A system and method of testing High Brightness LED (HBLED) is provided, and more particularly, a system and method of Controlled Energy Testing of HBLED with improved accuracy and repeatability is provided. In one embodiment, the system includes a programmable constant power source for providing a constant power to a Device Under Test (DUT), in this case, an HBLED, wherein the programmable constant power source adjusts an output voltage or an output current to ensure that a given amount of power is supplied to the HBLED for a predetermined amount of time and to provide precise control of a junction temperature of the HBLED for the duration of the test sequences; a Parametric Measurement Unit (PMU) including a processor for executing a plurality of HBLED test sequences, and a spectrometer for measuring a set of HBLED parameters including power and color (wavelength) of an optical output of the HBLED; and a controller for coordinating timing of acquiring the set of measured HBLED parameters. In another embodiment, a photodetector is implemented to measure the integrated power of the optical output of the HBLED.

System and method of testing high brightness led (hbled)

The existing diodes in an LED or laser diode package are used to measure the junction temperature of the LED or laser diode. The light or laser emissions of a diode are switched off by removing the operational drive current applied to the diode package. A reference current, which can be lower the operational drive current, is applied to the diode package. The resulting forward voltage of the diode is measured using a voltage measurement circuit. Using the inherent current-voltage-temperature relationship of the diode, the actual junction temperature of the diode can be determined. The resulting forward voltage can be used in a feedback loop to provide temperature regulation of the diode package, with or without determining the actual junction temperature. The measured forward voltage of a photodiode or the emissions diode in a diode package can be used to determine the junction temperature of the emissions diode.

Temperature measurement and control for laser and light-emitting diodes

A light device includes a housing and a tip structure configured to be removably coupled with the housing. The tip structure includes a light emitting device that is operable for emitting light positioned at a distal end of the tip structure and a body for housing the light emitting device. The housing is formed of an autoclavable material capable of withstanding autoclaving. A power supply circuit is positioned in the housing and coupled to the light emitting device to power the device when the tip structure is coupled with the housing. The power supply circuit is rechargeable and includes at least one ultracapacitor element for being charged and the power supply circuit configured to discharge the ultracapacitor as a current source to drive the at least one light emitting device.

Curing light device

A curing light device includes a body with a tip portion that has a plurality of elements for providing electrical energy to the distal end of the tip and for removing heat from the distal end of the tip. A light engine includes at least one light emitting element operable for emitting light and is positioned on the distal end of the tip portion. A power supply is positioned in the body and is rechargeable and includes at least one ultracapacitor element. Spring electrical contacts are positioned in the body and electrically coupled with the ultracapacitor element. The spring electrical contacts are spaced along the length of the body and configured for electrically engaging the tip portion along its length for delivering power to the light engine and for provide a spring alignment of the tip portion in the body.

Dental light device

The invention relates to a non-contact high-power light-emitting diode (LED) junction temperature test method which comprises the following steps: (A) obtaining a temperature sensitivity coefficient curve of LED junction voltage along with temperature changes when a current is small, (B) providing a normal working current for an LED and measuring the LED junction voltage after a temperature is balanced, (C) rapidly switching the normal working current into a small current and measuring an LED junction temperature at the moment by using a small current junction temperature measuring method, (D) fitting LED junction temperatures and junction voltages under different heat sink temperatures and obtaining an LED temperature sensitivity coefficient under the current, (E) changing the numerical value of the normal working current and repeating B-D to obtain LED temperature sensitivity coefficients under different working currents, and (F) measuring an LED junction voltage under an actual working state and obtaining an LED junction temperature at the moment according to an LED temperature sensitivity coefficient under the working current. Compared with the existing large current junction temperature test method, the non-contact high-power LED junction temperature test method is simple in operation, high in test accuracy and easy to use in practice.

Non-contact high-power light-emitting diode (LED) junction temperature test method

The present invention is a non-invasive method and associated apparatus for determining the junction temperature for an LED or laser diode (collectively “LED”) First a sample LED is placed in a heat chamber and the change of the LED's peak wavelength is recorded over time, as is the change in the temperature in the heat chamber Since the heat chamber supplies the major component to the junction temperature, dwarfing the other components, it is a reasonable proxy for true junction temperature The data is compiled to determine change of peak wavelength as a function of temperature and that function can then be used to determine junction temperature of similar LEDs that are installed in a system or manufactured The invention may also be used to measure other useful data, such as power, output power changing with the junction temperature and intensity of the LED over time and may be used to estimate failure rate

Desen Cao

Papers

Method and testing equipment for LEDs and laser diodes