Provided is a display apparatus having an LED module composed of a plurality of LED grids and mounted on a display panel; an LED driver module; a touch sensor mounted on the display panel; a control module configured to control an operation of the LED module; and a drawing device, assigned an identifier which indicates a unique color, and configured to grasp the grid coordinates of the LED grids corresponding to contact points with the display panel through light emitted from the LED module, wherein the control module receives the identifier assigned to the drawing device and the grasped grid coordinates from the drawing device, grasps position coordinates of the contact points through the touch sensor, specifies the identifier based on a comparison result between the received grid coordinates and the grasped position coordinates, and then displays a unique color at the contact point of the position coordinates.

Provided is a display apparatus having an LED module composed of a plurality of LED grids and mounted on a display panel; an LED driver module; a touch sensor mounted on the display panel; a control module configured to control an operation of the LED module; and a drawing device, assigned an identifier which indicates a unique color, and configured to grasp the grid coordinates of the LED grids corresponding to contact points with the display panel through light emitted from the LED module, wherein the control module receives the identifier assigned to the drawing device and the grasped grid coordinates from the drawing device, grasps position coordinates of the contact points through the touch sensor, specifies the identifier based on a comparison result between the received grid coordinates and the grasped position coordinates, and then displays a unique color at the contact point of the position coordinates.

A method for driving LEDs involves arranging the LEDs in a matrix. The LEDs are designed as RGB LEDs and are driven by means of a duty cycle control protocol.

An image detection device includes: a liquid resonant lens system whose focal point is cyclically changed; an image detector configured to detect an image of an object through the lens system; a pulsed illuminator configured to provide pulsed illumination to the object in synchronization with the focal point; and an illumination controller configured to control the pulsed illuminator, in which the pulsed illuminator includes a main illumination section and a supplementary illumination section, and the illumination controller is configured to provide pulsed illumination to the object with the main illumination section and supplement illuminance on the object with the supplementary illumination section when the illuminance on the object by the main illumination section is equal to or less than a predetermined threshold.

A charge voltage calibration system comprises a power supply, a light string, a driver, and a calibration circuit. The driver comprises a capacitor, a switch, and a sense resistor. The switch, sense resistor, and light string are coupled in series to form a discharge path coupled in parallel with the capacitor. The calibration circuit comprises a controller, a DAC, a comparator, a memory device. The controller is configured to control the DAC to provide a reference voltage to the comparator, cause the power converter to supply a first charge voltage to the driver, cause the switch to transition from an off state to an on state to discharge stored energy in the capacitor through the discharge path, and store a value of the first charge voltage in the memory device in response to detection of voltage generated across the sense resistor being greater than or equal to the reference voltage.

A system and method to determine a health status of a LED light string. The system (100) includes a circuit that includes a LED light string (110) and a pulsed current driver (115) of the LED light string. The circuit is connected to a power source (105). The system includes a current sensor (120) measuring a current through the circuit. The system includes a detecting device (130) determining a state of the circuit. The detecting device determines an expected current expected to be passing through the circuit where the expected current is associated with the state. The detecting device receives a current measurement from the current sensor during a time when the circuit is in the state. The detecting device determines a comparison between the current measurement and the expected current. The detecting device generates an output indicative of a health status of the circuit based on the comparison.

A system and method to determine a health status of a LED light string. The system (100) includes a circuit that includes a LED light string (110) and a pulsed current driver (115) of the LED light string. The circuit is connected to a power source (105). The system includes a current sensor (120) measuring a current through the circuit. The system includes a detecting device (130) determining a state of the circuit. The detecting device determines an expected current expected to be passing through the circuit where the expected current is associated with the state. The detecting device receives a current measurement from the current sensor during a time when the circuit is in the state. The detecting device determines a comparison between the current measurement and the expected current. The detecting device generates an output indicative of a health status of the circuit based on the comparison.

An LED driving system for synchronizing two LED driving integrated circuits to drive LED strings. The LED driving system sequentially activates the LED strings driven by the first LED driving integrated circuit and then outputs a downstream enabling signal from the first LED driving integrated circuit to the second LED driving integrated circuit to activate the LED strings driven by the second LED driving integrated circuit.

An LED driving system for synchronizing two LED driving integrated circuits to drive LED strings. The LED driving system sequentially activates the LED strings driven by the first LED driving integrated circuit and then outputs a downstream enabling signal from the first LED driving integrated circuit to the second LED driving integrated circuit to activate the LED strings driven by the second LED driving integrated circuit.

Examples are disclosed that relate to monitoring an emission state of light sources. One example provides a light emitting circuit comprising a power source, one or more light sources connected to an output of the power source, and a control circuit comprising a pulsed voltage source and a control transistor configured to regulate a current through the light sources based upon an output of the pulsed voltage source. The light emitting circuit further comprises a monitor transistor comprising a gate connected to an output of the light sources such that a voltage at the output of the light sources controls an output of the monitor transistor, and a monitor transistor detector connected to the output of the monitor transistor. The monitor transistor detector is configured to monitor a state of the one or more light sources based upon a state of the output of the monitor transistor.