Abstract: An automatically testable obscuration detector incorporates one of an electrically controllable filter or a mechanically selected filter. Filtered outputs can be compared to expected outputs by control circuitry to automatically assess detector operation.

Abstract: A method for creating large numbers of high-quality optical traps in arbitrary three-dimensional configurations and dynamically reconfiguring the traps under computer control. The method uses computer-generated diffractive optical elements to convert one or more optical tweezers into one or more optical vortices. The method involves combining the optical vortex technique with the holographic optical tweezer technique to create multiple optical vortices in arbitrary configurations.

Abstract: The present invention relates to an apparatus and method for imaging time resolved fluorescence in biochemical and medical samples. In a primary aspect, the device includes a lens of large aperture, a flash lamp in the illumination path, a fast-acting solid state shutter or a gated detector in the emission path, a device for delivering homogenous monochromatic illumination to a plurality of wells distributed within a microwell plate, a digital camera of high quantum efficiency, and a computer under computer control, the lamp is pulsed at short intervals. The fast-acting emission shutter or gated detector operates to limit exposure of the camera to a period some microseconds after the extinction of each lamp pulse, during which only delayed fluorescence is transmitted to the camera. The invention achieves simultaneous time resolved imaging of a plurality of samples, with high sensitivity and high throughput.

Abstract: An interior rearview mirror system suitable for use in a vehicle includes a interior rearview mirror assembly adapted for attachment to an interior portion of the vehicle. The interior rearview mirror assembly includes a housing and a reflective element included within the housing. The mirror system further includes a video device (which includes an imaging sensor) and a control. The imaging sensor is positioned at the interior rearview mirror assembly and has a field of view forward and through the windshield. The imaging sensor is operable to at least sense precipitation at an interior and/or exterior surface of the windshield. The control receives a signal from the imaging sensor and is operable to control at least one of a headlamp of the vehicle, a windshield wiper of the vehicle, a defogging system of the vehicle and a movable window of the vehicle in response to the signal.

Abstract: An optical moisture detector for determining a value corresponding to ambient light conditions and comparing that value to a predetermined value. The detector includes an optical moisture sensor and a processor. The optical moisture sensor can be a photo array, a CCD or a CMOS. The processor can be a microprocessor. The processor can emit a control signal to engage or disengage a light generating device based on the result of the comparison of the value to the predetermined value.

Abstract: The present invention relates to a method of determining at least one energy property of a gaseous mixture which consists in:

Abstract: The present invention relates to a method and an apparatus for use in performing a quantitative analysis of a turbid pharmaceutical sample, e.g. a tablet, a capsule or a similar sample forming a pharmaceutical dose. A pharmaceutical, turbid sample (24) is irradiated with an excitation beam (20) of radiation, e.g. near infrared radiation. The intensity of emitted radiation (30) from the sample (24) is detected as a function of both the wavelength of the emitted radiation and the photon propagation time through said sample (24). Optionally, the intensity of the emitted radiation (30) from the sample (24) is also detected in a spatially resolved manner.

Abstract: Described is an optical element having plural electrodes and, disposed therebetween, a stimuli-responsive polymer gel, a liquid which can be absorbed therein and an ion supplying material. As the ion supplying material, preferred is a material showing a volumetric change, in the form of the element, of 0 to 100% under external stimuli. According to the present invention, a novel optical element showing a large change in light transmittance, reflectance or absorption amount and exhibits stable optical properties in repetition can be provided.

Abstract: A particle sizing method and apparatus of the PIDS type uses randomly polarized radiation to irradiate a particle sample. Portions of the resulting side scattering pattern are decomposed to simultaneously produce, for each decomposed portion, first and second linearly polarized beams of radiation in which the respective planes of polarization of the two beams are mutually perpendicular. Each of the polarized beams is focused onto a photodetector, and the respective photodetector outputs are differentiated to provide PIDS signals that are useful in calculating a particle size distribution for the sample.

Abstract: The invention relates to a transmission sensor (1) for measuring the turbidity of a fluid, comprising a first and a second measuring section (2, 3). A transmitter (6) emits electromagnetic radiation into the two measuring sections (2, 3). A first receiver (14) is allocated to the first measuring section (2) and a second receiver (15) is allocated to the second measuring section (3). The transmitter (6) is inserted into a transmitter carrier (8) in such a way that the transmitter (6) is forced to adopt a predetermined oriented position. The receivers (14, 15) are inserted into a receiver carrier (18) in such a way that each of said receivers (14, 15) is forced to adopt a predetermined oriented position. A transmitter carrier holder (9) forcibly positions the transmitter carrier (8) in a predetermined location and a receiver carrier holder (19) forcibly positions the receiver carrier (18) in a predetermined location.

Abstract: A preferred embodiment of a system for measuring a level of a fluid comprises a light source adapted to generate light having a predetermined wavelength, an optical waveguide slab at least partially filled with a material adapted to fluoresce when illuminated by the light having a predetermined wavelength, and a light pipe. The light pipe is adapted to transmit the light having a predetermined wavelength to the optical waveguide slab at an angle that causes the light to be internally reflected only within a portion of the optical waveguide slab located above the fluid thereby illuminating the fluorescent material within the portion of the optical waveguide slab located above the fluid. The preferred embodiment also comprises a photo-multiplier tube adapted to generate an electrical output in response to the fluorescence of the fluorescent material.

Abstract: A rain sensor for a motor vehicle is proposed, having a transmitter (16) emitting radiation, a receiver (18), and a holographically embodied diffractive element (22a, 22b) that has a linear-grating-like structure.

Abstract: Fiber-optic-based systems and methods for monitoring physical parameters using a remotely deployed circulator are disclosed. In a preferred embodiment the circulator is remotely deployed with respect to an optical source/detector and coupled thereto by two dedicated fiber optical cables: a forward line for passing light from the source through the circulator to fiber-optic-based sensors, and a return line for passing light reflected from the sensors through the circulator back to the detector. By using separate forward and return lines in conjunction with the circulator, backscattering phenomenon experienced on the forward line will not interfere with the reflected light signals coming from the sensors. The circulator, and hence the sensors, may therefore be remotely deployed from the source/detector present at a monitoring station, greatly expanding distances which optical sensing systems can span.

Abstract: A rain sensor for a vehicle including a light emitting device and a light receiving device that receives a portion of light reflected by a windshield is provided. The rain sensor comprises a variable resistor device and a control unit. The variable resistor device realizes a specific resistance that relates to an output value of the rain sensor. The control unit is configured to calculate infrared ray transmissivity of the windshield based on one or more parameters of the rain sensor, and to control the variable resistor device such that the resistance of the variable resistor device is determined according to the calculated transmissivity.

Abstract: An optical sensor includes a sample cell through which a fluid flows, an optical sensor formed by an optical emitter and an optical detector. The sample cell and the optical sensor use light refraction to determine the presence and size of a bubble passing through the sample cell. A housing may also be included to provide better control over light refraction and to protect the optical sensor.

Abstract: A mobile gas detector comprising a laser transmitter and signal analyser carried on a vehicle, the vehicle having an exterior, a laser absorption cell carried on the exterior of the vehicle, a light guide connecting light from the laser transmitter into the laser absorption cell, a photo-detector mounted with the laser absorption cell exterior to the vehicle to convert light that has traversed the laser absorption cell into electrical signals, and a cable connecting the photodetector to the signal analyser.

Abstract: An unsealed optical encoder does not function properly in a fluid other than air because the optics do not function when interfaced with a medium having an index of refraction significantly higher than air. The collimating lens of an optical encoder has two refracting surfaces, at least one of the refracting surfaces being convex. An orthogonal cap of the present invention is attached over an optical encoder's collimating lens to create a sealed air cavity between the convex refracting surface of the collimating lens and the orthogonal cap. This placement of the orthogonal cap is such that the collimated light leaving the sealed air cavity may enter the surrounding medium at an angle that is normal to the surface of the medium, such as transparent oil, so that the collimated light does not bend even though the light is traveling from air to a much slower medium.

Abstract: A system is provided for positioning separate portions of a sample in elongate, parallel channels of a sample chamber and for irradiating a sample in the chamber to create a diffraction pattern where the sample and chamber differ in refractive index. The system also can measure absorption of electromagnetic radiation by a sample in the chamber, and can measure the absorption simultaneously with measurement of diffraction by the sample.

Abstract: A method and apparatus for spectrochemical analysis of liquids, including molten metals, using laser-induced plasma spectroscopy. The apparatus preferably comprises a high power pulsed laser focused on the surface of a liquid stream flowing in a measurement cell, and an optical spectrometer-detector assembly, which receives, detects and analyzes the radiation emitted by the high temperature plasma thereby excited. The measurement cell, and optional pump, establish laminar flow of the liquid flow, thereby permitting the laser to repeatedly sample a fresh un-perturbed surface, while also ensuring that bubbles formed in the liquid are removed from the focal volume Preferably, a blower prevents aerosols and matter ejected from the sample responsive to the incident energy from interacting with subsequent laser pulses, and from accumulating on the optic.

Abstract: A method for creating large numbers of high-quality optical traps in arbitrary three-dimensional configurations and dynamically reconfiguring the traps under computer control. The method uses computer-generated diffractive optical elements to convert one or more optical tweezers into one or more optical vortices. The method involves combining the optical vortex technique with the holographic optical tweezer technique to create multiple optical vortices in arbitrary configurations.

Abstract: In an apparatus for the conversion of a continuous liquid stream into a stream of liquid droplets, which are discharged from a discharge nozzle of the capillary through which the liquid stream is conducted, a flow acceleration device is disposed on the capillary near the discharge nozzle thereof for accelerating the droplet stream depending on a first electrical signal, which is applied to the acceleration device, and a second electrical signal which is generated by a laser detection means provided for sensing laser light of a beam directed through the travel path of the droplets to the detection means for sensing the passage of a droplet and means for generating from the first and second electrical signals a time &Dgr;t which indicates the time needed for a liquid droplet to travel from the discharge nozzle to the laser light beam.

Abstract: Devices for the measurement of volumetric flow rate of a gas in a conduit are described. A vane arrangement is subjected to airflow and is displaced I response thereto. The vane arrangement forms a light guide, and one end of the vane arrangement receives an encoded light source, the encoding being over the range of displacement of the vane. In one form, the encoding can be achieved by a light source and a mask, the mask being shaped to provide for variance of the light transmitted therethrough as a function of the vane displacement range. One form of mask can be a tapered arrowhead. Embodiments of the flow rate measurement device offer good dynamic response. The measuring device can be incorporated in CPAP or ventilatory assist devices for the control thereof.

Abstract: A diffracting portion is composed of optical elements including an optical element, and diffracts light. A drive unit rotates the optical element. An angle detector detects a rotation angle of the optical element. A reference wavelength light source includes a light source and an absorption cell sealed with a plurality of gasses of different kinds having mutually different absorption line wavelengths, and emits the reference light of a specific wavelength depended on the absorption cell toward the diffracting portion. A reference photodetector converts a diffracted light from the diffracting portion into an electric signal. A signal processor receives a rotation angle issued by the angle detector when detecting a predetermined value of the electric signal, and determines the predetermined rotation angle corresponding to the specific wavelength determined depending on the plurality of gases.

Abstract: A method and apparatus for spectrochemical analysis of liquids, including molten materials, using laser-induced plasma spectroscopy. The apparatus preferably comprises a high power pulsed laser focused on the surface of a liquid stream flowing in a measurement cell, and an optical spectrometer-detector assembly, which receives, detects and analyzes the radiation emitted by the high temperature plasma thereby excited. The measurement cell, and optional pump, establish a steady flow of liquid, thereby permitting the laser to repeatedly sample a fresh unperturbed surface, representative of the liquid volume, while also ensuring that bubbles and waves formed in the liquid are removed from the focal volume. Gas (usually air) blown above the liquid prevents aerosols and matter ejected from the sample responsive to the incident energy from interacting with subsequent laser pulses, and from accumulating on the optics.

Abstract: An optical detection system for flow cytometry that uses two or more light sources positioned laterally at different distances from a central axis of a flow stream for providing light through different parts of the flow stream. One or more lenses are used to focus the light from the two or more light sources through the flow stream and onto a common focal point or region on the opposite side of the flow stream. One or more light detectors are then placed at, near or around the common focal point or region. A processor or the like receives at least one output signal from the one or more light detectors to analyze and determine selected characteristics of the flow stream.

Abstract: A fiber optic liquid level detector uses optical fibers to detect the presence or absence of liquids. The waveguide properties of optical fibers tends to deviate from the normal dielectric interfaces so that a fiber immersed in a liquid has a reflection coefficient smaller than when surrounded by air. This is caused by the differences in refractive indices of liquid and air and is used to measure the amount of light transmitted or reflected by the fiber in the preserve or absence of a liquid.

Abstract: A fiber optic sensor for measuring level of fluid consists of an ordered array of multiple optical fibers. Each fiber contains a single sensitive element located on a specific level within the range of fluid level change that transmits different light signals depending on either the sensitive element is immersed in the fluid or located above the level of liquid. The input of the fiber bundle is illuminated by an encoded light beam. A decoding system provides detection of the light patterns at the output and processes it to display the readings. Number of fibers in the bunch determines the number of sensitive sections positioned at different levels and, correspondingly, the accuracy of level measurement.

Abstract: A raindrop detecting apparatus has a temperature sensor, an EEPROM, a processor and a raindrop sensor. A temperature characteristic data is defined by a first temperature data of the temperature sensor and a first output data of the raindrop sensor produced at a first temperature condition, and stored in the EEPROM. The processor updates a raindrop detection threshold by using the stored characteristic data, a second temperature data and a second output data produced at a second temperature, when an engine is started under no-raindrop condition. The processor compares an output data of the raindrop sensor with the raindrop detection threshold to detect a raindrop, while converting at least one of the characteristic data and the output data in correspondence with a temperature data produced at a raindrop detection time.

Abstract: A raindrop detection apparatus has an amplifier circuit, including a plurality of resistors and resistor selection switches. The control circuit performs the first adjustment to an output of the amplifier circuit, roughly adjusting the output to a target value. The first adjustment is made by selecting one of or a combination of resistors. The control circuit then performs the second adjustment to the output, closely adjusting the output to the target value. The second adjustment is made by adjusting a driving instruction signal, which actually adjusts a light emitting device driving current. These adjustments are performed after an IG switch and an AUTO mode switch of a wiper switch are turned on.

Abstract: An automatic transmission fluid tester determines the remaining service life of automatic transmission fluid. The tester includes a radiation source for emitting radiation in the direction of an automatic transmission fluid sample under test, and a radiation receiver for detecting radiation passed through the sample. Based on the output of the radiation receiver, the tester measures the opacity of the sample. The remaining service life of the automatic transmission fluid is determined as a function of the measured opacity.

Abstract: An apparatus (10) and method for detecting and analyzing the spectra of light emitted by a plasma (36) in a plasma duct (16) having a plurality of windows (40) formed therein. In one embodiment, the apparatus includes an optical system (50) arranged adjacent each window that directs light emanating from the plasma and passing through each window to two or more optical filters (F1, F2) having different bandwidths so that different portions of the light spectra (S1, S2) can be measured. The filter light is incident respective two or more detectors (D1, D2), which produce an electrical signal representative of the intensity of light incident thereon, and thus is a measure of the content of a select band of the light spectrum. Performing this measurement for different regions (R) of the plasma yields different spectra and thus provides information about the plasma properties, thereby allowing for adjustment of those properties.

Abstract: The present invention provides a method for spectrophotometric analysis of a beverage, which method comprises analyzing the beverage while contained in a closed end consumer container. The present invention also provides a device for analyzing a beverage that comprises an analyzing means for analyzing the beverage while contained in a closed end consumer container. The analyzing means comprises a detector arranged for detecting electromagnetic radiation which has been transmitted through the beverage.

Abstract: An optical fuel level sensor for providing an electronic signal representative of the fuel level within a fuel tank, generally comprising a waveguide body, a photo source, and a photo receiver. The waveguide body can either be of a dual-tapered or single-taper shape and includes numerous tiered facets, which are angled surfaces located on the outer periphery of the waveguide. When the fuel level within the fuel tank is above a particular tiered facet, light that impinges that facet will refract out of the waveguide, conversely, when the fuel level is below that facet, impinging light will be reflected back into the waveguide such that it is received by the photo receiver. In this manner, the fuel level sensor is able to utilize the reflected light received by the photo receiver to provide an electronic signal representative of the fuel level. Furthermore, a calibration feature may be included which provides calibration information indicating when the fuel level has reached a known, predetermined level.

Abstract: This specification discloses a method and apparatus for the mobile and remote detection of a gas, such as methane, in the atmosphere. The apparatus includes a TDL based Light Detection and Ranging (LIDAR) driven at carrier frequency lying within the absorption line of the gas. The apparatus also drives the TDL with a modulation frequency to generate upper and lower sidebands in the output of the TDL and with a low ramp frequency to sweep the output of the TDL across twice the width of the pressure-broadened absorption line of the gas, preferably the first overtone absorption line in the case of methane detection. The apparatus include reference and calibration cells or chambers, and includes a light collector and detectors to detect the quantity and modulation of the light that passes the reference or calibration cells and that is received by the apparatus after reflection back toward the apparatus from an uncooperative target.

Abstract: A method of and system for analyzing image data representative of a sequential set of images of a spray plume, each of the images being representative of a density characteristic of the spray plume (i) along a geometric plane that intersects the spray plume, and (ii) at a predetermined instant in time, that in one aspect comprises sequentially displaying the set of images so as to exhibit a time evolution of the spray plume along the geometric plane. The invention may further integrate the set of images so as to exhibit a time-average representation of the images. In one embodiment, the invention comprises a general purpose computer executing software that receives and sequentially displays the set of images so as to exhibit a time evolution of the spray plume along the geometric plane, and provides a user interface for measuring one or more spray plume parameters associated with the spray plume within one or more of the images.

Abstract: The present invention pertains to a sensor, suitable for use in the detection of an analyte in a fluid, comprising: a tube (4) defining a flow path for the fluid; a generally planar member (3) mounted in the flow path (→) such that the plane is in the direction of flow, wherein the member has, bound thereto, a ligand that interacts with the analyte, wherein interaction causes the member to flex; and means (1, 2) for the detection of the flexing.

Abstract: A liquid measuring cell for measuring optical properties of liquids, with a measuring chamber (16), which is adjoined on one side by a transparent window (11), and with a reflector (30) disposed on the opposite side of the measuring chamber (16), which reflects the light striking it toward the outside through the measuring chamber (16) and the window (11), is particularly easy to clean and permits favorably reproducible measurements if another transparent window (33) is disposed between the reflector (30) and the measuring chamber (16) and this window (33) adjoins the measuring chamber (16) on the other side.

Abstract: A method and apparatus for measuring fluid motion with micron scale spatial resolution has been developed. Here, micron or submicron solid fluorescent particles are injected into the fluid body. The particles are chosen to closely follow the motion of the fluid. Pulses of light, at the excitation wavelength, broadly illuminate the test device and the fluorescent particles, The flourescent particles absorb the excitation light and emit pulses of fluorescent light, at the emission wavelength. The fluorescent light is collected by a microscope objective lens, and relayed through a fluorescent filter to an image recording device, such as a CCD camera. Subsequently, discrete images of discrete particles at two or more instances in time are recorded. These images can then be analyzed using correlation analysis to obtain velocity measurements.

Abstract: A smoke detector includes a housing defining a dark chamber admitting test atmosphere. A light receiver is disposed within the chamber. A scatter emitter is positioned within the chamber such that light strikes the receiver when reflected off particles suspended in the test atmosphere. An obscuration emitter is positioned within the chamber such that light emitted is directed to the receiver unless obstructed by particles suspended in the test atmosphere. A smoke detect signal is generated responsive to a measurement made responsive to the scatter emitter and/or the obscuration emitter.

Abstract: The object is to provide a technique whereby a non-operating nozzle can be detected with higher accuracy. The present invention resides in a printer for printing images by ejecting ink droplets from a plurality of nozzles, wherein an optical path in which light from a light-emitting element 40a for emitting light is focused by a first focusing element 41, allowed to pass through a focusing aperture 43a that is substantially circular and smaller than the area illuminate by the light, and transmitted through the focusing aperture 43a to a light-receiving element 40b for receiving light is laid out according to a configuration in which an intersection is formed with the path described by the ink droplets ejected by the nozzles. The light-emitting element 40a is energized and caused to emit light.

Abstract: A photo expansion gas detector includes a radiation emitter, a sample gas, an expansion gas hermetically sealed in a chamber, and a capacitive diaphragm for sensing pressure changes. The radiation emitter may be constant or may be cycled on and off. Radiation passes through the sample and into the expansion gas. The expansion gas expands according to the intensity of the radiation received. The capacitive diaphragm is impacted directly by the expansion gas. The capacitive diaphragm deflects relative to a fixed capacitive plate, resulting in changes in capacitance representing expansion and contraction of the expansion gas. The electrical signal generated by the changes in capacitance represent changes in the gas composition of the sample. The electrical signals are then processed to activate control systems.

Abstract: A precipitation sensor has a prism bonded to a front windshield, a beam transmitter, and a beam receiver. The prism has an entry-side prism wall, a connection wall, and an exit-side prism wall. The entry-side prism wall of the prism parallelizes light transmitted from the beam transmitter by refracting them on a convex lens face. The parallelized light is reflected from a parabolic outer face of the prism wall toward the inner face of the windshield. The parallel beams reflected from the inner face of the front windshield are reflected from a parabolic outer face of the exit-side prism wall and then focused on the beam receiver through a convex lens face of the prism wall. The convex shapes of the lens faces form arcs, the centers of which are aligned with the beam transmitter and the beam receiver, respectively.

Abstract: In an isotopic gas analyzer, a gas injector (21) is provided for pressurizing a gas specimen in cells (11a,11b). The pressurization of the gas specimen virtually produces the same effect as increasing the concentration of carbon dioxide in the gas specimen, thereby improving an S/N ratio for the analysis and hence data reproducibility.

Abstract: An apparatus for measuring the velocity of a droplet of a liquid includes a laser to generating a beam of light and projecting the beam along a first path. A lens is along the first path for forming the beam into the shape of a thin sheet. A beam divider is along the first path for dividing the beam into two separate beams which extend along second and third paths. The second and third paths lie in a common plane. Along the second and third paths is means for projecting a droplet of liquid across the second and third paths so that the droplet passes through both of the divided beams. AT least one photodetector is along the second and third paths to receive the divided beams and provide an electrical signal corresponding to the beams.

Abstract: For adjusting output voltages of a turbidity sensor which is used for measuring the turbidity of a medium by means of a radiation at least partially propagating through the medium being emitted from a sender and being received by a receiver, ohmic loads for the receiver on its output side are adjusted such that desired output voltages are obtained.

Abstract: The present invention relates to a method of building instrument variation tolerance into calibration algorithms for spectroscopic devices for chemical composition analysis with spectroscopic methods. The method of the present invention is particularly suitable for blood glucose, cholesterol and other chemical components prediction based on near-infrared spectrophotometry measurements. A method includes developing a calibration algorithm on a first instrument; applying the calibration algorithm to a second instrument; calibrating the second instrument and adjusting the calibration algorithm to account for differences between the first instrument and the second instrument; and repeating the step of applying (above) in respect of (n) further instruments to provide a calibration algorithm which may then be used on other instruments.

Abstract: A method and assembly for sensing moisture on the exterior surface of a sheet of glass (14) comprising the steps of emitting light rays from an illuminator (12) on an illuminator axis (I) intersecting the glass (14) at an illuminator angle of incidence I&thgr; to reflect the light rays on a reflection axis (R) at an angle (R&thgr;) of reflection to the glass (14) and capturing on an imaging axis (C) the reflected light rays including reflections of moisture (19) on the exterior surface of the glass (14). The method is characterized by isolating the reflection of moisture (19) from the direct reflection of the illuminator (12) to prevent the capture of the direct reflection of the illuminator (12). This can be accomplished by offsetting the imaging axis (C) from the reflection axis (R), or by stopping the direct reflection of the illuminator (12) from being captured, as with a beam stop (24).

Abstract: A method and assembly for sensing moisture on the exterior surface of a sheet of glass (16) by capturing an ambient image (A) of light rays passing through the glass (16) from the exterior to the interior surfaces thereof under ambient light conditions. The invention is characterized by illuminating (18) the glass with pulses of light rays, capturing an illuminated image of the glass containing the ambient image (A) plus the illuminated image (B) containing the reflected light from the illuminating (18) of the glass (16) between the ambient images (A), and subtracting each ambient image (A) from the next adjacent illuminated image (B) to produce a moisture signal (30).

Abstract: An optical sensor includes a sample cell through which a fluid flows, an optical sensor formed by an optical emitter and an optical detector. The sample cell and the optical sensor use light refraction to determine the presence and size of a bubble passing through the sample cell. A housing may also be included to provide better control over light refraction and to protect the optical sensor.

Abstract: The present invention provides a highly universal out-of-liquid sensor that allows an out-of-liquid condition to be accurately detected for a long time, and provides a liquid supply device using the same.