Analysis of the causes of malfunction of the lighting device (LED, other light sources)

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8. Analysis of the causes of malfunction of the lighting device (LED, other light sources).
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Any supply or installation of lighting equipment directly at the facility may be associated with the occurrence of its malfunctions or failure both during the connection process and during operation, despite guarantees from the manufacturer or supplier.

Any supply or installation of lighting equipment directly at the facility may be associated with the occurrence of its malfunctions or failure both during the connection process and during operation, despite guarantees from the manufacturer or supplier.

Qualitatively, failure can be characterized as:

- complete inoperability of the lighting device

- the extinction of the LEDs, matrices

- significant (at times) decrease in luminous flux

- increase in pulsation of the light flux

- change in the spatial distribution of luminous intensity.

The reasons for the failure of lighting devices (light sources) can be many, for example:

- Inadequate mains voltage (light source power supply voltage)

- the presence of emissions or harmonics in the supply feeder

- malfunction or failure of the lighting device driver

- malfunction or failure of the lighting part (LEDs, other light sources)

- failure of auxiliary elements of the electrical circuit of the lighting device

In varying degrees, these reasons point to the corresponding responsibility for the occurrence of a similar situation both on the part of the consumer and on the part of the manufacturer (supplier). The proposed research program allows you to establish the true cause (because of what a malfunction arose: poor-quality LEDs and what is their defect, mismatch of power supply and causes of nonconformity, various influences, etc.) and a technical picture of failure or reconstruction of the malfunction scenario and thus determine the appropriate share of responsibility of the parties to the transaction. Also, this program can be used by developers of lighting devices to determine the causes of malfunctions in order to appropriately correct the design or electrical circuit of the product. This program can also be used to establish the operating conditions for lighting products or to restore the type of possible impacts during operation based on their results - the manifestation of a malfunction. For most products based on LEDs, in addition to analyzing the causes of inoperability, it is possible to study the quality of production (performance of manufacturing operations of the assembly, etc.) of LEDs and radiating crystals, the definition of the manufacturer of crystals and LEDs, their binic combination of parameters and its compliance with the specifications or the actual characteristics.

The Fault Analysis Protocol includes: a description of the malfunction, quality indicators, photographs, measurements of various photometric values ​​or electrical modes, explanations and comments with conclusions and conclusions about the causes of the malfunction.

Examples of visualization of the analysis of failed LEDs and the interpretation of their malfunction, which form the basis for describing the causes of the revealed malfunctions, are given in the illustrations and in the text fragments.

“In the luminaire, CREE HTT-E type LEDs are used, in which the emitting crystal is fixed on a ceramic substrate using the“ flip-chip ”method and does not have contact threads to ohmic contacts. A protective diode crystal is installed in parallel to the radiating device, working in the opposite direction and preventing the first from breaking through with high reverse voltage.

Analysis of faulty LEDs has shown that the described short circuit condition with zero internal resistance can be caused by ...

.... It should be recalled that the LED is a device capable of operating at frequencies up to 800 MHz. In this case, the protective diode remained intact, but to check the above version of the cause of the malfunction, it was excluded from the circuit by breaking its contact filament. ”

Examples of the study of malfunction LEDs with epoxy lens housing.
 

The study of the quality of the technological operation of the installation of the crystal in the body of the LED.