300results about How to "Improve flickering" patented technology

An alternating current (AC) light emitting device includes an AC light emitting diode (LED) module and a waveform modulation unit. The AC LED module includes at least two sets of micro-diodes. The waveform modulation unit coupled between the AC LED module and an AC voltage source modulates a waveform of the AC voltage source.

This invention generally relates to solid state lighting control, and more particularly to a dimmer interface circuit and a method for reducing ringing on a drive signal to a solid state lighting device. An embodiment is a dimmer interface circuit for controlling brightness of a solid state light emission device, the interface circuit having an input to receive a brightness control voltage from a dimmer circuit and comprising: a voltage converter to provide a converter output voltage and having an inductive component and a charge store, the charge store controllably coupled to receive charge from the inductive component to thereby convert the brightness control voltage to the converter output voltage; and control circuitry comprising: an input to receive a voltage level indication of the brightness control voltage; an input to receive a voltage level indication of the converter output voltage; a comparison circuit to compare a said received brightness control voltage level indication and a said received converter output voltage level indication; and a transition detector to detect a transition of the brightness control voltage, said transition for turning a said solid state light emission device on, wherein the control circuitry is configured to control the voltage converter dependent on a said comparison of said level indications received at a time of a said transition in a first cycle of the brightness control voltage, such that a difference between the brightness control voltage and the converter output voltage at a time of a said transition in a second, later said cycle is closer to a target voltage difference or target voltage difference range than a said difference at the time of the transition in the first cycle.

An organic light emitting display device includes a display panel including and a plurality of pixels, a gate driver configured to a normal gate signal and an alternative gate signal to the pixels, a data driver configured to provide a data signal to the pixels, an emission control driver configured to an emission control signal to the pixels, and a controller configured to control the gate driver, the data driver, and the emission control driver. Each of the pixels is driven by the normal gate signal in a first driving mode and is driven by the alternative gate signal in a second driving mode. A threshold voltage of a first transistor is compensated in the first driving mode and the threshold voltage of the first transistor is not compensated in the second driving mode.

Disclosed are electronic control gears for LED light engines able to improve power factor by way of gearing up or down the LED current and the AC input current in response to and in synchronization with the AC input voltage. Moreover, the disclosed electronic control gears could further reduce flicker phenomenon and total harmonic distortion when used in collocation with disclosed valley fillers, filling the LED current valleys only during the dead time, and in conjunction with disclosed dummy loads, ramping up or down the AC input current only during the dead time.

The invention relates to a grid pulse modulation circuit and a shading modulation method thereof. The grid pulse modulation circuit is provided with an output end, a voltage modulation circuit and a comparison control circuit, wherein the voltage modulation circuit is coupled between a grid power supply voltage and a second preset voltage and receives control of a shading control signal so as to shade and make the output end output a voltage signal for shading; the comparison control circuit comprises a comparator and a switch component; and the first input end of the comparator is coupled to a node of the voltage modulation circuit, while the second input end is coupled to a first preset voltage. When the voltage modulation circuit performs shading operation, the relative magnitude relation between the voltage at the node point and the first preset voltage decides the switching on and switching off states of the switch component so as to decide the occasion that the first preset voltage is transmitted to the output end.

The disclosure relates to a pixel circuit and a driving method thereof. The pixel circuit comprises a first transistor and a second transistor whose control terminals receive first scanning signals; athird transistor and a fourth transistor whose control terminals receive second scanning signals; a fifth transistor whose control terminal is electrically connected to a first capacitor; a sixth transistor, a seventh transistor, and an eighth transistor whose control terminals receive control signals; and a light emitting diode. According to the pixel circuit and the driving method thereof, an electric leakage current can be reduced or reversely supplemented, the capacitance maintenance capability of the capacitor is improved, the flickering degree of images can be improved, and the stability of the displayed images is improved.

The invention discloses an organic electroluminescence display panel and a display device. The threshold voltage of the driving transistor drifts due to reasons such as process, device aging and the like, and the compensation transistor is arranged to compensate the threshold voltage before the pixel driving circuit controls the OLED to display, so that the saturation current of the driving transistor is irrelevant to the threshold voltage of the driving transistor. The orthographic projection of the third metal layer on the substrate covers the orthographic projection of the compensation transistor on the substrate; in this way, electric leakage of the compensation transistor due to illumination can be prevented, so that potential rise of the grid electrode of the driving transistor of the pixel driving circuit due to electric leakage of the compensation transistor in the light-emitting stage can be avoided, and the grid-source voltage of the driving transistor can be prevented from becoming small. Furthermore, attenuation of OLED brightness can be reduced, and the problem of image flickering of the display panel is effectively solved.

The light-emitting module according to one embodiment comprises first to Nth light-emitting element packages (wherein N is a positive integer greater than or equal to 1), which are connected in series to one another, and a current level regulator for regulating the level of current flowing through the Nth light-emitting element package. Each of the first to Nth light-emitting element packages comprises a light-emitting cell comprising a plurality of sub-cells, which comprise at least one light-emitting element and are connected in series or parallel to one another, and a flicker control unit, which is connected between the plurality of sub-cells and selectively forms the path or current flowing through the light-emitting cell according to the level of an external driving voltage. At least one of the first to Nth light-emitting element packages further comprises a first current control resistor connected to the output of the light-emitting cell.

The invention discloses a liquid crystal display which comprises a liquid crystal panel, a display control circuit and a data driven circuit, wherein the display control circuit is used for receiving an image signal and generating a time sequence signal and a data signal according to the image signal; the data driven circuit is used for receiving the time sequence signal and the data signal so asto form a plurality of data voltages; and before the data voltage for driving a non-polar inversed pixel is pre-output, the data driven circuit is used for adjusting the voltages of a plurality of data wires to be preset voltage, so that the electric charge quantity stored by a polar inversed pixel is the same as that stored by the non-polar inversed pixel for the same-gram scale frame. The liquid crystal display can be used for improving the phenomenon that the frame flashes when the image of the liquid crystal display is displayed and has a better display effect.

Disclosed herein are a driving circuit and a lighting apparatus for a light emitting diode capable of improving a flicker, light efficiency, and electrical characteristics. The disclosed driving circuit for a light emitting diode includes: a dimmer modulating an AC voltage input depending on a selected dimming level; a rectifier full-wave rectifying the modulated AC voltage output from the dimmer to generate and output a driving voltage; and a driving module receiving the driving voltage of the rectifier to detect the selected dimming level and controlling a driving mode of a plurality of light emitting diode groups depending on the detected dimming level, in which the driving module selects one of a resistance driving mode driving all the plurality of light emitting diode groups and a sequential driving mode sequentially driving the plurality of light emitting diode groups to improve light efficiency and electrical characteristics.

The present invention relates to a dynamic contrast ratio processing method and apparatus of a liquid crystal displaying apparatus. The method includes: performing a histogram statistics processing on input data of the present frame, dividing a statistics processing result into N gray groups, and calculating the a data amount corresponding to each gray group; setting gray groups whose corresponding data amounts are larger than or equal to a first threshold as gray groups with priority, and setting a gray group having the highest luminance in gray groups with priority as a main priority gray group; determining whether the luminance of the main priority gray group of the present frame is the same as that of the main priority gray group of a previous frame; if it is, comparing data amounts with corresponding tolerance values to determine whether it is necessary to change the luminance control parameter, otherwise, obtaining the luminance control parameter of the present frame according to the main priority gray group of the present frame; outputting the luminance control parameter of the present frame at last. The present invention improves flickering phenomenon effectively and enhances picture quality.

The invention discloses a display panel driving circuit and method. The display panel driving circuit comprises a time sequence controller, a data driving circuit and a scanning driving circuit; the display panel is a display panel with a zigzag structure; the polarities of the gray scale voltage signals on the data line in front and back adjacent frames of images are opposite; polarity of each row of sub-pixels in each frame of image is reversed at an interval of every m columns; the gray scale voltage signals of two adjacent data lines in the m columns of data lines correspond to a first signal and a second signal with opposite polarities, wherein the first signal is greater than a positive reference gray scale voltage signal, the second signal is less than a negative gray scale reference voltage signal, m is greater than or equal to 2, m is an even number, common electrode voltages on each row of sub-pixels are mutually offset, and the common electrode voltage offset is zero, so that the image flickering phenomenon of the display panel is improved.