444results about How to "Guaranteed linearity" patented technology

The invention provides an illuminating device. The objective of the invention is to inhibit overshoot current flowing over semiconductor light source and hold linear relationship between ON duty of determined light consumption and light consumption amount. In conduction of light emitting diodes LEDs 1 to 4, a switching signal 101 is converted into a voltage V 2 or 0V through a signal converter 26 in accordance with a logic level thereof The voltage obtained by the conversion is compared with a voltage V 1 on both ends of a resistor R 1 through an operational amplifier 20 to open / close an output loop by an NMOS transistor 22, a current If of the light emitting diodes LEDs 1 to 4 is limited to a current If 1 so as not to exceed a maximum current, and a current defined with an ON duty of the switching signal 101 is caused to flow as a mean current to the light emitting diodes LEDs 1 to 4 to inhibit an overshoot current from flowing to the light emitting diodes LEDs 1 to 4 while the output loop is closed.

Provided is a multi-mode multi-frequency power amplifier (100), comprising: a controller (120) for receiving and outputting control signals based on external signals; a broadband amplifier channel (110) for receiving single-frequency or multi-frequency radio-frequency (RF) signals via an input end, conducting power amplification on the RF signals, and outputting the signals via an output end; a fundamental wave impedance convertor (170) comprising a first segment (130) shared by RF signals in respective frequency bands, a second segment (150) dedicated for RF signals in each frequency band, and a switch circuit (140), the switch circuit (140) being controlled by the controller (120) to switchably separate the RF signals with amplified power to the second segment (150) for multiple outputs.

A package device for applying pre-stress on a fiber grating sensor comprises, on a pedestal, a left mounting base connected with a left moving stage, a right mounting base connected with a right moving stage, a platform lifting rod sleeve arranged between the left mounting base and the right mounting base, a left lifting sleeve arranged on the left moving stage, a right lifting rod sleeve arranged on the right moving stage, a translation conversion mechanism arranged on the left and the right moving stages, a left lifting rod arranged on the top of the left lifting rod sleeve and connected with a left clamp frame, a right lifting rod arranged on the top of the right lifting rod sleeve and connected with a right clamp frame, and a platform lifting rod arranged on the upper end of the platform lifting rod sleeve and connected with a platform. The package device has the advantages of simple mechanical structure, small size, low cost, easy operation, etc., and can be used in a temperature range of subzero 25 DEG C to above-zero300 DEG C to achieve high-temperature curing package when applying pre-stress to a fiber grating. The fiber grating sensor packaged by the device has no chirp and waveform aberration, thus ensuring the repeatability and the linearity of the sensor.

The invention discloses a wireless surface acoustic wave temperature measurement system reader-writer, which consists of a signal generating unit 101, an amplifier unit 102, a band-pass filter 103, a radio frequency switch 104, a crystal oscillator 105, a local oscillator 106, a band-pass filter 107, a low noise amplifier 108, a filter 109, an intermediate frequency amplifier 110, an analog-digital conversion module 111 and a digital signal processing module 112. The reader-writer has a double phase-locked loop structure, ensures that the expected frequency can be achieved during transmission and receiving, and provides guarantee for accurately measuring temperature.

The invention provides a method for improving the sensitivity and linearity of a latex reagent. An adopted detection kit comprises a reagent R1 and a reagent R2. The method is characterized in that the latex reagent is a latex reagent mixed with latexes with large and small particle sizes, and is processed to prepare a C-creative protein latex turbidimetric detection kit, and the kit comprises the reagent R1 and the reagent R2. The method comprises the following steps: (1) directionally coating latex microspheres with large particle sizes with mouse to-be-tested antigen monoclonal antibodies; (2) directionally coating latex microspheres with small particle sizes with rabbit or sheep to-be-tested antigen monoclonal antibodies; (3) mixing the coated latex microspheres with the large particle sizes and the coated latex microspheres with the small particle sizes.

The invention relates to a pressure sensor, in particular to a fully symmetric miniature silicon resonant pressure sensor. The fully symmetric miniature silicon resonant pressure sensor is based on lateral drive and can solve the problem of nonlinear driving force in an upper and lower planar plate driving structure and the problem of coupling between the driving force and a pressure sensitive diaphragm. The pressure sensor is provided with a resonant structure, four frustum-shaped silicon islands, a square silicon pressure sensitive diaphragm, a silicon frame and a lower glass layer; the inside of the silicon frame and the square silicon pressure sensitive diaphragm are connected into a whole; the four frustum-shaped silicon islands are symmetrically arranged on the diagonals of the square silicon pressure sensitive diaphragm; the four sides of the four frustum-shaped silicon islands are parallel to the four sides of the square silicon pressure sensitive diaphragm; the four frustum-shaped silicon islands suspend the resonant structure above the square silicon pressure sensitive diaphragm in parallel via four support beams connected with the four frustum-shaped silicon islands; and four lead electrodes on the four diagonals on the upper surface of the silicon frame are connected with the resonant structure via four flexible beams, thus realizing the electrical connection between the resonant structure and the outside.

The embodiment of the invention discloses a level switching circuit which comprises two operational amplifiers and a common-mode feedback loop. A substrate and a PMOS source follower which is connected with a source electrode are inserted in a P point of each operational amplifier, so that big difference oscillation amplitude 3.3V high common-mode level is horizontally moved to 1.2V low common mode level with low degree of distortion, and the difference oscillation amplitude is kept unchanged. The common-mode feedback loop receives output signals of the two operational amplifiers, common-mode taking operation is conducted on the two output signals, an obtained common-mode value is compared to a set reference voltage, and the comparison result is used as a feedback signal to be output to the two operational amplifiers. The embodiment of the invention further provides the operational amplifiers and a programmable gain amplifier. According to the level switching circuit, the operational amplifiers and the programmable gain amplifier, the function of switching from low level to high level and the function of switching from the high level to the low level can be achieved at the same time, and the demand for large outputting oscillation amplitude and high linearity is met.

The embodiment of the invention discloses a crest clipping method and crest clipping equipment for a multiband broadband signal. By applying the technical scheme of the embodiment of the invention, a crest value of a received multiband multi-carrier signal which is processed by a digital to analog converter (DAC) is forecasted; corresponding crest pre-clipping processing is performed according to a forecast result, and a crest factor of the received multiband multi-carrier signal processed by the DAC is ensured; therefore, the problem of the crest factor of the signal because the single channel of the conventional base station equipment adopts a broadband power amplifier and supports multiple bands at the same time is solved; the linearity and the efficiency of the power amplifier are guaranteed by using a digital predistortion scheme; and a multiband application technology of the same system, a common mode technology of different systems and a common platform implementation technology are feasible.

The invention discloses a capacitance sensor, comprising a sensor gauge head, inner electrodes and an outer electrode, wherein the inner electrode is composed of a plurality of independent electrodes; the inner electrodes are the same in inner and outer diameters and are coaxially arrayed; the inner electrodes respectively comprise a top compensation electrode, a multi-section measurement electrode and a bottom compensation electrode from top to bottom; each two sections of electrodes are connected through a connecting piece which is made of an insulating material; the outer electrode is sleeved at the outer parts of the inner electrodes through screw threads, is coaxially mounted with the inner electrodes and is commonly shared by each section of the electrode in the inner electrodes; and the sensor gauge head is connected with the outer electrode. According to the capacitance sensor disclosed by the invention, the influences on liquid level measurement of temperature, pressure, mediums and the like are eliminated and the precision of the liquid level measurement is improved; and furthermore, an electricity leakage phenomenon can be effectively avoided and the linearity of the sensor is guaranteed.

The present invention provides a receiving / transmitting switching device which is used for realizing the receiving / transmitting switching of the TDD wireless communication system. The receiving / transmitting switching device comprises a power amplifier, a low-noise amplifier and a circulator, and also comprises the following components: a quarter-wave microstrip which is used for impedance conversion and has a first end connected to the third port of the circulator and a second end connected to the input end of the low-noise amplifier; a first switching element which has a negative pole connected to the third port of the circulator and a positive pole connected to the first end of the inductor; a second switching element which has a negative pole connected to the second end of the quarter-wave microstrip and a negative pole earthed; a load resistor which absorbs the reflected wave of the transmitted signal and the leakage signal of the circulator and coverts to heat energy, wherein the first end of the load resistor is connected to the positive pole of the first switching element and the second end is earthed; and an inductor which operates a high resistance function to the radio frequency through the direct current bias thereby guaranteeing that the low-noise amplifier will not be damaged by the large signal at any working time.

A radiofrequency power amplifier device and a radiofrequency power amplification method. The radiofrequency power amplifier device comprises an N-number of parallel-connected power branches; each power branch comprises phase shifters and Doherty power amplifiers, where N is an integer greater than 1. The phase shifters are configured to perform phase compensation on a signal. The present solution performs combination of two or more Doherty power amplification, performs phase adjustment on the combined Doherty power amplification, and introduces the phase shifters into a combiner Doherty circuit to perform phase compensation on the signal, thus ensuring indicators such as efficiency and linearity while increasing the efficiency of power amplification, while at the same time, allowing for increased convenience and easiness in debugging, for improved consistency of the device, and for improved operational reliability. The present solution also meets new requirements of users, such as the requirements for increased power and increased peak-to-average power ratio.

The invention relates to the field of analog integrated circuit design of microelectronics in order to further expand and improve an input range and linearity of the traditional time domain ADC and reduce a delay matching error, and adopts the technical scheme that a time domain ADC (Analog to Digital Converter) based on a cycle time digital converter consists of three circuit modules. The circuit module I is a voltage-time converter VTC comprising two sampling switches Sh, two discharge switches Sd, two sampling capacitors CH or CL and Cref, two current supplies I and two comparators Com1 and Com2; one end of the first sampling switch Sh is connected with an analog input VH or VL; and the other end of the first sampling switch Sh is connected with one end of the sampling capacitor CH or CL and one end of the first discharge switch Sd. The other end of the sampling capacitor CH or CL is earthed. The ADC is mainly applied to the analog integrated circuit design.

An MEMS accelerometer comprises a substrate, an acceleration sensitive chip and an integrated circuit, wherein the acceleration sensitive chip and the integrated circuit are arranged on the substrate, a temperature sensor is further arranged on the substrate and is adjacent to the acceleration sensitive chip, and the acceleration sensitive chip comprises a plurality of measurement bodies. Each measurement body comprises a mass block and a comb tooth structure, wherein the comb tooth structure comprises movable comb teeth extending from the mass block and fixed comb teeth, the movable comb teeth and the fixed comb teeth are arranged at intervals and form a difference detection capacitor, the comb tooth structure is divided into multiple groups, the multiple groups of comb teeth structures are divided into a first part and a second part, the variation direction of movable intervals of the comb tooth structure of the first part and the variation direction of movable intervals of the comb tooth structure of the second part are opposite, and one group of the comb tooth structure and one group of the comb tooth structure of the second part respectively output an electric signal. The MEMS accelerometer resolves the problems that a traditional MEMS accelerometer is large in temperature factor and large in temperature hysteresis.

The invention provides a pushing device used for mounting elevated frames and bridges and a pushing method of the pushing device. A bridge box girder is circularly jacked through a pushing unit and a jacking unit to move; when used, the pushing device does not permanently produce horizontal thrust on a pier, cost is reduced while smoothness, safety and linearity of the bottom of the bridge box girder in pushing the bridge box girder are guaranteed at the same time, and the affect of special landform conditions on the positions across the structure of the bridge box girder upon slide construction is effectively avoided.

The invention discloses a portable rapid water quality detector and a water quality detection method, and belongs to the technical field of water quality analysis and detection. The portable rapid water quality detector comprises an LED light source and a detection assembly, wherein the detection assembly comprises a four-light-transmitting cuvette, an LED light source intensity detection module,an ultraviolet absorption light intensity detection module and a fluorescence light intensity detection module; the LED light source is used for emitting ultraviolet light to the four-light-transmitting cuvette; the ultraviolet absorption light intensity detection module is used for detecting the light intensity of ultraviolet light which is not absorbed after passing through the four-light-transmitting cuvette; the fluorescence light intensity detection module is used for detecting the light intensity of the fluorescence light which is excited by a to-be-detected liquid passing through the four-light-transmitting cuvette; and the LED light source intensity detection module is arranged between the LED light source and the corresponding light transmission surface and is used for detecting the light intensity of ultraviolet light emitted by the LED light source in real time. The portable rapid water quality detector can be used after startup, and the water quality detection by the devicecan more accurately reflect the substance composition contained in the to-be-detected liquid.

The invention relates to an in vitro diagnostic kit and in particular relates to a D-dimmer latex-reinforced immunonephelometry detection kit cooperatively adopting an ion stabilizer and a suspension stabilizer. The D-dimmer latex-reinforced immunonephelometry detection kit cooperatively adopting the ion stabilizer and the suspension stabilizer comprises two components, namely a reagent R1 and a reagent R2, wherein the reagent R1 mainly consists of a buffer solution 1, a stabilizer 1, a preservative 1, a coagulation accelerator and a protective agent 1; the reagent R2 mainly consists of a buffer solution 2, two polystyrene latex microspheres crosslinked with different D-dimmer monoclonal antibodies, a stabilizer 2, a protective agent 2 and a preservative 2, and the stabilizer 2 in the reagent R2 adopts the ion stabilizer and the suspension stabilizer which are used cooperatively. Compared with the prior art, the D-dimmer latex-reinforced immunonephelometry detection kit cooperatively adopting the ion stabilizer and the suspension stabilizer has the advantages that a latex-reinforced immunonephelometry method is adopted, and detection can be carried out under the condition that wavelength is 400-800nm, so that the detection is easier and the D-dimmer latex-reinforced immunonephelometry detection kit cooperatively adopting the ion stabilizer and the suspension stabilizer can be applied in clinical more easily.

The invention discloses a flow two dimension velocity field measurement method and a flow two dimension velocity field measurement device based on near field scattering. The flow two dimension velocity field measurement device based on the near field scattering comprises a laser, a space filter, a collimating lens, a lens group, a CCD (charge coupled device) camera and a computer. Compared with the prior art, the flow two dimension velocity field measurement device based on the near field scattering has the advantages of being pretty simple in structure, low in demand for light path centering, and capable of achieving the purpose of effectively removing stray light under the circumstance that a complex device for eliminating central light strength is not needed. The particle diameter of tracer particles needed by a measurement technology used in the flow two dimension velocity field measurement method based on the near field scattering can be less than the wavelength of incident light emitted from the laser, and concentration of the tracer particles is high, and therefore the measurement technology can be used in measurement of a nanometer fluid flow two dimension velocity field. The measurement technology is simple and quick in data analysis, can achieve online measurement, and guarantees that accuracy and linearity of the flow two dimension velocity field measurement method based on the near field scattering are not limited by the particle diameter and the concentration of the tracer particles by using a differential processing method.

The invention discloses a wireless respiration monitoring device, comprising a monitoring circuit, a piezoelectric film sensor and an antenna, wherein the control circuit is respectively and electrically connected with the piezoelectric film sensor and the antenna. In the wireless respiration monitoring device, the piezoelectric film sensor is used for sensing respiratory movement and converting the respiratory movement into corresponding charge signals, the control circuit is used for processing the charge signals to obtain a corresponding monitoring result, and the antenna is used for transmitting the monitoring result out. Because the piezoelectric film sensor adopted in the invention has the favorable characteristics of high response speed, high sensitivity and good linearity, the accuracy and the correctness of respiration signals are guaranteed; and in addition, because the antenna is used for transmitting the monitoring result out and cables or other transmission lines are avoided being used, the wireless respiration device provided by the invention has a simple structure and is easy to produce and manufacture.

The present invention discloses a gain fluctuation adjusting circuit which consists of a first resonance circuit that is connected with the 90 Dgr phase end of a 3dB bridge and a second resonance circuit that are connected with the 0 Dgr phase end of the 3dB bridge and both are connected in series. The present invention also discloses a gain fluctuation adjusting method, the signals are divided into two groups after entering the 3dB bridge and the two groups enter the first resonance circuit and the second resonance circuit respectively. The two resonance circuit processes the signals and return theses signals back to the 3dB bridge which reunify the two groups of signals and then sent out. The present invention can adjust the variable capacitance of the two resonance circuit so as to adjust the in-band gain fluctuation of the circuit. The present invention can compensate the inclination of the gain of the amplifier within the range of the frequency domain through changing the resonance point of the resonance circuit by adjusting the variable capacitance, which improves the index of the in-band wave and ensures linearity of the power amplifier and normal work. Furthermore, the present invention is convenient to be controlled and easy to be carried out with low cost.

The invention relates to a mechanical plate shearing machine, in particular to a mechanical plate shearing machine utilizing a swing guide rod mechanism. The structure is that a cover plate is fixedly installed at the upper end of a lateral support I and a lateral support II of the plate shearing machine. T-shaped supports are symmetrically installed at two ends on the lower side of the cover plate, the upper ends of the T-shaped supports are fixed with the cover plate, and the lower ends of the T-shaped supports are sleeved on two sides of a spindle in empty mode. Execution mechanisms are symmetrically installed on the spindle section between the lateral support I and one T-shaped support and between the lateral support II and the other T-shaped support. The mechanical plate shearing machine has the advantages of being novel in structure, convenient to modify, low in cost, safe, good in economy and safety and the like, thereby being a novel mechanical plate shearing machine integrating economy and practicability.

The invention discloses a high-speed linear frequency-sweeping laser source. The high-speed linear frequency-sweeping laser source comprises a tunable laser, a first optical switch, a polarization controller and a frequency shift ring, wherein the frequency shift ring is formed by sealing a first input port and a first output port of an optical fiber coupler; an optical isolator, a frequency shifting device, an optical amplifier, a second optical switch, a band-pass filter and the polarization controller are successively connected in series in the frequency shift ring through an optical fiber; then pulsed laser enters the optical fiber coupler; the laser is split in the optical fiber coupler; part of optical signals are directly output by a second output port of the optical fiber coupler; the other part of the optical signals are subjected to frequency shift again in the frequency shifting ring through the first output port of the optical fiber coupler; the optical signals subjected to frequency shift are split again by the optical fiber coupler. The process is recycle repeatedly; the frequency shift of laser is achieved in each cycle; the laser is output at different time, so that the high-speed, single-direction and K-space linear output of the frequency-sweeping laser with discrete wavelength, tunable wavelength interval and extremely narrow instant line width is achieved.

The invention relates to a fin cutting machine for a plate-fin heat exchanger, which is characterized by comprising a bracket, a cutting device, a cutting guide device, a cutting power device and a pressing device, wherein the bracket is provided with a fin cutting platform; the cutting device is used for cutting fins, and comprises a cylinder, a tool post and a cutting blade; the tool post is fixed on a piston rod of the cylinder; the cutting blade is arranged on the tool post; the cutting guide device comprises guide rods fixed on the bracket; the cylinder is arranged on the guide rods and can slide leftwards and rightwards along the guide rods; the cutting power device is arranged on the bracket, and is used for driving the cylinder to slide leftwards and rightwards along the guide rods; and the pressing device is arranged on the fin cutting platform, and is used for pressing the fins in the cutting process of the cutting blade to prevent the fins from moving forwards. The fin cutting machine is particularly suitable for cutting the fins of the plate-fin heat exchanger, and can cut the fins more efficiently and accurately.

The invention provides an integrated differential silicon capacitor microphone employing two or four differential MEMS sensitive elements which are in parallel connection and share one sound cavity. The microphone comprises a housing and a substrate, which are combined together. Moreover, one of the housing and the substrate is provided with a sound incoming hole. The microphone also comprises the two or four differential MEMS sensitive elements which are matched with each other; an integrated circuit; and a sound cavity. The integrated circuit is used for the buffering / amplification and output of an electric signal which is formed by the conversion of a sound wave through the sound incoming hole, the sound cavity and the differential MEMS sensitive elements. The electrical arrangement and connection mode between the integrated circuit and the differential MEMS sensitive elements are in axial symmetry or mirror symmetry relation. Through the means provided by the invention, the microphone improves the linearity and the maximum sound pressure level.

A stroke amount detecting device includes a first magnetic field generation member (21, 25), a second magnetic field generation member (22, 26), and a magnetic sensor unit (7, 8). The first magnetic field generation member (21, 25) and the second magnetic field generation member (22, 26) are opposed to each other with respect to a direction perpendicular to a straight stroking axis of a stroking object, and magnetized in opposite directions. The magnetic sensor unit (7, 8) is movable in an area between the first magnetic field generation member (21, 25) and the second magnetic field generation member (22, 26), along a straight traveling axis (X) that is parallel to the straight stroking axis relative to the first magnetic field generation member (21, 25) and the second magnetic field generation member (22, 26) in accordance with a stroke motion of the stroking object. The magnetic sensor unit (7, 8) has a magnetosensitive surface (5a, 6a) facing a direction parallel to the traveling axis (X), thereby to detect an amount of stroke of the object.

The invention discloses a high-precision, high-field strength and capacitive sensor device for measuring a miniature electric field based on a piezoelectric effect. The sensor device comprises a piezoelectric membrane layer. An upper electrode layer is attached below the piezoelectric membrane layer. The upper electrode layer is supported by a supporting layer. A fixed reference layer is arrangedbelow the upper electrode layer. The fixed reference layer is electrically connected with an impedance detection apparatus. The upper electrode layer is electrically connected with the impedance detection apparatus through an electrode guiding column. The beneficial effect is that: the device has a large electric field measurement range, a high response and sensitivity, and an adjustable linearity; the device can also meet the requirements for monitoring power grid steady state operation and identifying overvoltage fault transient signals except for real-time monitoring large electrical equipment in industrial production.

The invention discloses a low-range and high-sensitivity micro-electromechanical system (MEMS) pressure sensor which comprises a monocrystalline silicon layer (1), a porous silicon / silicon composite membrane structure (6), a porous silicon voltage dependent resistor (7) and a metal layer (8), wherein the back surface of the monocrystalline silicon layer (1) is provided with a concave cavity; the porous silicon / silicon composite membrane structure (6) is formed in the concave cavity in the back surface of the monocrystalline silicon layer (1); the porous silicon voltage dependent resistor (7) is formed on the front surface of the monocrystalline silicon layer (1); the metal layer (8) is deposited on the porous silicon voltage dependent resistor (7) and has a function of metal interconnection. The invention further discloses a manufacture method of the low-range and high-sensitivity MEMS pressure sensor. Porous silicon materials have excellent piezoresistive performance and mechanical performance, and therefore, the porous silicon MEMS pressure sensor adopting the structure can keep degree of linearity and improve sensitivity simultaneously, and can be applied within a superlow pressure range by means of flexible structure design.

The image reading unit is provided with: a xenon lamp; a frame 601 having first and second side walls 60a (60b); a reflection unit for reflecting light reflected on an original; a lens unit for forming an image from the light reflected on the reflection unit; an image sensor for converting the light forming the image in the lens unit to electric signals; first and second supporting plates 750a (750b) disposed on the outer side of the first and second side walls 60a (60b) for supporting the reflection unit. The first reinforcing plate forms a guide unit for supporting the other side of the scanning unit in the main scanning direction and guiding the scanning unit in the sub-scanning direction. The driving source and the drive transmitting unit are fixed to the second reinforcing unit.

A distributed antenna device includes a plurality of transmit antenna elements (12), a plurality of receive antenna elements (30) and a plurality of amplifiers (14, 140). One of the amplifiers (14) is a relatively low power, linear amplifier operatively coupled with each of the transmit antenna elements (12) and mounted closely adjacent to the associated transmit antenna element (12), such that no appreciable power loss occurs between the power amplifier (14) and the associated antenna element (12). At least one of the amplifiers (140) is a low noise amplifier and is built into the distributed antenna device for receiving and amplifying signals from at least one of the receive antenna device for receiving and amplifying signals from at least one of the receive antenna elements (30).

The invention provides a closed-loop envelop tracking system calibrating method. The method comprises the following steps: transmitting a wireless signal in a wireless system by a wireless transmitter with a radio frequency (RF) module utilizing an envelope tracking (ET) adapting a power amplifier (PA) supply voltage with a PA target response; obtaining a reference signal on-the-fly, wherein the reference signal is a baseband digital signal of the transmitted wireless signal using a modulation signal specified by the wireless system; obtaining a detection signal on-the-fly through a coupler, wherein the detection signal is a partial feedback from down-sampled PA outputs; computing a difference between a measured response and the PA target response based on the reference signal and the detection signal; and adjusting a PA supply voltage compensation look up table (LUT) based on the computed difference to maintain the linearity of the ET. Accordingly, the invention also provides a closed-loop envelop tracking system calibrating apparatus, in order to improve the linearity of the ET.

The invention provides a lens holder driving device whch is aimed at ensuring the linearity of driving characteristics in a wide scope. A lens holder driving device includes a lens holder in which a lens assembly is mounted, a driving coil fixed to the lens holder at outside circumference thereof, an outer yoke including an outer hollow cylindrical portion and an ring-shaped end portion disposed an upper end of the outer hollow cylindrical portion, a magnet disposed to an inner wall surface of the outer hollow cylindrical portion so as to be opposite to the driving coil, an elastic member supporting the lens holder in a direction of an optical axis shiftably, and a base disposed at a lower side of the lens holder. The lens holder driving device includes a contact area reduction arrangement (146a) reducing a contact area between the ring-shaped end portion of the outer yoke and an upper end portion of the lens holder.