49results about How to "Solve the problem of strobe" patented technology

The invention discloses an organic light-emitting device with long service life. The organic light-emitting device comprises a first electrode, a second electrode and an organic light-emitting element containing a phosphorescent light emitting layer or a delayed fluorescence light emitting layer between the first electrode and the second electrode. The organic light-emitting device further comprises a pulse alternating-current drive circuit driven by forward pulse voltage V1 or forward pulse current I1 so that the organic light-emitting element can emit light. The pulse alternating-current drive circuit applies inverse pulse transient pulse voltage V2 reverse to the forward pulse voltage V1 or the forward pulse current I1 after applying the forward pulse voltage V1 or the forward pulse current I1. The application control time of the inverse pulse transient pulse voltage V2 in each cycle is less than or equal to 10 micro seconds. According to the organic light-emitting device with long service life, the service life of a screen of the organic light-emitting device is effectively prolonged on the condition that stroboflash is reduced.

A healthy and smart classroom lighting system comprises a server, a host computer and a plurality of classroom overall light systems. The server is connected with the host computer. The host computeris connected with each classroom overall lighting system through a local area network; the classroom overall lighting system includes a central processor, a control device and a plurality of lamp systems installed in the classroom, and the central processor is connected to the host computer; the lamp system includes a ZigBee receiving control module, a driving power supply, a load lamp, a light color control processor MCU, and a light color sensor; and the lamp system includes a blackboard light system in a blackboard lighting zone, a teacher light system in a teacher teaching zone, and a classroom light system in a student learning zone. The healthy and smart classroom lighting system solves the problems of stroboscopic flash, glare, illumination and light color coordination, and uses anintelligent control system to adapt the visual requirements of the students in different classroom activity scenes through an intelligent natural light compensation module and a mode preset control function.

The invention discloses a low frequency ripple suppression circuit and a control method. The low frequency ripple suppression circuit comprises an energy buffer and ripple suppression unit and an AC-DC power factor correction type constant current source circuit, wherein the energy buffer and ripple suppression unit is connected in parallel to a constant current source output voltage Vled of the front stage AC-DC power factor correction type constant current source circuit; the AC-DC power factor correction constant current source circuit is used for realizing power factor correction while providing a constant current output for the load; the energy buffer and ripple suppression unit is used for realizing front stage output voltage Vled low ripple; when the output voltage Vled of the frontstage AC-DC power factor correction type constant current source circuit rises instantaneously, energy on a second capacitor is transferred onto a first capacitor to charge the first capacitor; and when the output voltage Vled of the front stage AC-DC power factor correction type constant current source circuit drops instantaneously, the energy on the first capacitor is transferred onto the second capacitor to discharge the first capacitor. Through adoption of the low frequency ripple suppression circuit, LED load ripple can be reduced while ensuring no energy loss and increasing the system efficiency.

The invention discloses a circuit capable of solving the problem of strobing of an LED high-voltage linear constant-current driving scheme. The circuit comprises a rectifying circuit body, a high-voltage linear constant-current driving IC body, an LED lamp string and a capacitor charging and discharging circuit body. The rectifying circuit body converts directly-input alternating-current voltage signals into pulse direct-current signals. The high-voltage linear constant-current driving IC body converts the pulse direct-current signals into voltage applicable to each segment of LEDs in a sectional mode and proper constant currents are provided for the LEDs. The LED lamp string comprises the LEDs and an isolating diode. The capacitor charging and discharging circuit body comprises a capacitor charging circuit and a capacitor discharging circuit. When the high-voltage linear constant-current IC body is connected, a capacitor is charged. When the high-voltage linear constant-current driving IC body is disconnected, the capacitor discharges to provide energy for the LEDs connected with the capacitor in parallel. Thus, it can be guaranteed that each segment of the LEDs is always turned on in the whole input voltage cycle, and the whole circuit solves the problem of strobing of an LED device on the condition that the input power factor and harmonic waves are not affected.

The invention relates to an LED linear dimming drive circuit which comprises an input module, a rectifier module connected with the input module, a voltage regulator module and a power control module connected with the rectifier module, and an LED load module. The LED linear dimming drive circuit further comprises a regulation module of which a first end is connected with the voltage regulator module and a second end is connected with the power control module. According to the LED linear dimming drive circuit, commercial power is converted into steady DC power, the DC power is compared with the current of a regulator through an operational amplifier, the magnitude of current flowing through the LED load module is controlled linearly, and thus, the luminous brightness of LED is regulated. The problem of LED light flickering caused by other nonlinear ways of dimming is avoided. The service life of LED is prolonged.

The invention relates to a paper defect detection method based on the local brightness invariance priori, which comprises the following steps of 1, photographing the surface of paper to be detected byusing a color area array camera, and capturing a frame of color image with a pixel format of RGB components; 2, carrying out nonlinear graying operation on all pixels of the color image in the mask of the convolution template by using a convolution template with local brightness invariance priori, and finally obtaining pixels corresponding to the convolution window; according to the 1*1 convolution operation and the 3 * 3 convolution operation, obtaining two gray level images respectively; 3, carrying out corresponding position pixel division on the two grayscale images to obtain a grayscaleimage; 4, performing 3 * 3 Fourier convolution operation on the grayscale image; 5, performing gradient morphological operation on an operation result; 6, performing thresholding processing to obtaina paper defect detection result. According to the present invention, a common light source and an area array camera can be used for detecting paper defects, and a detection system is low in complexity, high in accuracy and low in cost.

The invention discloses a parking stall guiding method and device. The method includes obtaining a plurality of vehicle-free state frame images of a parking stall, and adding to a background queue; when stroboflash of a parking stall indicator light is judged to occur, obtaining a current frame image of the parking stall; calculating Euclidean distance between an HOG feature of the current frame image and an HOG feature of each vehicle-free state frame image in the background queue, and determining a parking stall state of the current frame image; and controlling the turning-on state of the parking stall indicator light through the parking stall state of the current frame image. The method solves the problem of stroboflash of the indicator light.

The invention provides an LED driving circuit. The LED driving circuit is characterized by comprising a resonance transformation main circuit and a control circuit. The control circuit comprises a comparison circuit, a setting circuit and a parameter transformation circuit. The control circuit detects output currents and output voltages of the resonance transformation main circuit, superposes the output currents and the output voltages as currently superposed values in the setting circuit, according to the size relation between the currently superposed values and a reference superposed value, decides whether the parameter transformation circuit is at a rapid loop state or a slow loop state, and accordingly controls the response speed of the comparison circuit in outputting control signals. In such a way, when the output currents are quite small and the output voltages are quite low, the resonance transformation main circuit, if entering a hiccup mode, can enable the control circuit to rapidly respond to the output voltages and the output currents of the resonance transformation main circuit so that the hiccup efficiency is improved, current ripples output by the resonance transformation main circuit are reduced, and the stroboscopic or scintillation phenomenon of an LED load connected with an LED driver is solved.

The invention relates to an LED driving module. The LED driving module comprises a PWM detection circuit which is used for detecting and outputting a PWM dimming signal; a linear dimming circuit whichis used for controlling the sampling voltage to be reduced along with the reduction of the duty ratio of the PWM dimming signal according to the PWM dimming signal; a PWM processing circuit which isused for outputting a first level when the duty ratio of the PWM dimming signal exceeds a set value, and outputting a second level when the duty ratio of the PWM dimming signal does not exceed the setvalue; and a selection circuit which is used for inputting the PWM dimming signal into the control end of the switching tube for PWM dimming when the PWM processing circuit outputs the first level, and starting the linear dimming circuit for linear dimming when the PWM processing circuit outputs the second level. By combining PWM dimming with linear dimming, the problems of stroboflash and dimming depth in PWM dimming can be solved to the maximum extent, and the LED dimming effect is optimized.

The invention provides a lighting system, which comprises an integrating circuit, a driving circuit and a light source. A pulse width modulation signal is connected into the input end of the integrating circuit, and the integrating circuit is used to convert the pulse width modulation signal into an analog signal. The control end of the driving circuit is connected into the output end of the integrating circuit. The output end of the driving circuit is connected with the light source. The duty cycle corresponding to the pulse width modulation signal is directly proportional to the voltage corresponding to the analog signal. The lighting system of the invention avoids the stroboflash problem of the light source caused by direct PWM dimming. At the same time, because the voltage value of theanalog signal output by the integrating circuit is directly proportional to the duty cycle of the input pulse width modulation signal, the process of adjusting the brightness of the light source through the analog signal is synchronized with the PWM dimming signal. Therefore, flicker-free dimming is realized on the premise of ensuring the dimming accuracy, and the damage to the human body causedby the stroboflash of the light source is avoided.

The invention relates to a display brightness adjusting device and a display device. The display brightness adjusting device comprises a first polarizer, a polarization adjusting layer and a second polarizer; the polarization adjusting layer is arranged at one side of the first polarizer, and is used for changing the polarization direction of light penetrating through the first polarizer; and thesecond polarizer is arranged at one side of a polarization direction adjusting layer away from the first polarizer. The display brightness can be adjusted by enabling the light emitted from a displaypanel to pass through the first polarizer, the polarization adjusting layer and the second polarizer, wherein the polarization state of the light emitted by the display panel changes after passing through the polarization adjusting layer, thus the brightness of the light emitted from the second polarizer can be adjusted, so that the display brightness is adjusted, and the problem that the displaydevice is stroboscopic caused by adjusting the brightness of the display device through PWM is solved.

The invention discloses a stroboflash-free active power factor correcting circuit applied to LED drive. The stroboflash-free active power factor correcting circuit applied to LED drive comprises a rectifying circuit, a filtering capacitor, a first-level inductor, a control chip, a power tube, a transformer and an LED load circuit and is characterized by further comprising an energy storage capacitor, a first switch tube and a second switch tube, wherein one end of the first-level inductor is connected with the output end of the rectifying circuit, the other end of the first-level inductor is connected with the drain electrode of the power tube and the positive pole of the energy storage capacitor, the transformer comprises at least one main coil, one end of the main coil of the transformer is connected with the source electrode of the power tube through a sampling resistor, and the other end of the main coil of the transformer is in parallel connection with the negative pole of the energy storage capacitor. The stroboflash-free active power factor correcting circuit provides direct current constant source through the energy storage capacitor, two times of ripple waves of power frequency are eliminated, no stroboflash is output while power factor correction, the circuit is simplified, and cost is reduced.

The invention relates to a stroboflash-free high-precision constant-current LED (light emitting diode) drive circuit and an operating method thereof. The high-precision constant-current LED drive circuit comprises an LED drive and an energy storage unit connected with the LED drive, the LED drive is internally provided with an MOS (metal oxide semiconductor) tube and a feedback signal input end, and the energy storage unit is coupled with a feedback circuit to acquire feedback signals which are inputted into the feedback signal input end. The stroboflash-free high-precision constant-current LED drive circuit has the advantages that by the aid of the LED drive internally provided with the MOS tube and the feedback signal input end, integrity of the drive circuit is improved, and the problem of LED stroboflash can be avoided only by one LED drive; a peripheral circuit of the LED drive circuit is more simplified by an internal overvoltage protector, and high reliability is achieved; the LED drive is free of hiccups and is directly locked when an output voltage is higher than an overvoltage protection reference voltage, so that the LED drive is further protected.

The invention provides an intelligent lighting system comprising a first control module used for receiving a control instruction of a user and converting the control instruction into corresponding light source demand information; the second control module is connected with the first control module, and the second control module is used for receiving the light source demand information and generating a corresponding PWM control signal at regular time according to the light source control information; and converting the PWM control signal into a corresponding direct-current voltage signal through a GP8500 chip so as to control the target illuminating lamp to emit light with corresponding color temperature and illuminance value. Therefore, the PWM wave is used as the output to control the dimming of the target illuminating lamp, and the conversion with the direct-current voltage is realized through the GP8500 chip, so that the stroboflash problem in the PWM dimming is effectively solved.

The invention discloses a stroboflash-free eye protection table lamp control system. The system comprises a micro-control unit module, and the micro-control unit module is electrically connected withan LCD display module, a touch key module, a power supply management module, an LED light source driving module, a learning time timing module and a sitting posture adjusting module. The power supplymanagement module is unidirectionally and electrically connected with an LED light source, and the LED light source is bidirectionally and electrically connected with the LED light source driving module. The stroboflash-free eye protection table lamp control system is equipped with an LED light source module, a stroboflash-free LED driving module and a stroboflash test module, the stroboflash problem of an LED eye protection table lamp can be well solved; after the brightness and the color temperature of the LED desk lamp are adjusted, the fluctuation depth of the luminous intensity of the LEDeye protection desk lamp is small, the change of the brightness is small, and the stroboflash-free effect can be basically achieved; the test measurement of the fluctuation depth and a stroboflash curve can be completed by a low-cost method, and a better use prospect is brought.

The invention discloses an LED driving power supply which comprises a filter circuit, a first non-isolated DC/DC power supply circuit and a second non-isolated DC/DC power supply circuit which are connected in sequence. The main power switch tubes in the first non-isolated DC/DC power supply circuit and the second non-isolated DC/DC power supply circuit are arranged on a bus, one is arranged at ahigh-voltage end, and the other is arranged at a low-voltage end. Under the condition that the cost is not increased, the main power switch tube in the non-isolated DC/DC power supply circuit not onlymeets the normal work of the LED driving power supply, but also blocks the electric leakage of the LED driving power supply, so that the problem that the dimmable LED driving power supply in the prior art cannot truly realize the dimming turn-off function is solved; in addition, the stroboflash problem of the LED driving power supply can be effectively solved, the PF value is increased, the lossis reduced, and the input and output range of the LED driving power supply is wide.