Why did the heat dispersion fail?

In LED lighting, The designer will consider that heat dispersion with their experience. the heat dispersion is major problem for LED design 。

we have a few strange phenomenon during use. may be caused by heat dispersion . so what reason for heat dispersion fail? Here is three key point:

1.thermal resistance was too large and the metal-insulator transition temperature ( Tp) becomes unmeasurable. so led source’s not giving out any heat.
2.In design ,use the aluminium based plates to connecting led source. the aluminium based plates had multiple thermal . so led source’s not giving out any heat.
3. The designer have not set aside for heat dispersion buffer. so led source’s not giving out any heat.
Stated thus, good treatment measures for heat dispersion is necessary in design .