The present invention relates to LED structures and, more particularly, to active blue light leakage preventing LED structures.
The earth is more and more consumed and damaged by people when the progress of living keeps advancing. Hence comes the need for the everlasting existence of the earth with the increasing demands for energy saving and environmental protection solution. Out of those demands, light-emitting diodes (LEDs) advantageously feature small physical volume, high brightness, low power consumption, and ease of use and replacement and become the most rapidly growing application.
Wherein the life span or life limit of LED, known as L70, is commonly defined as the light emitted by a LED reduces to about 70% of its stable emission value. However, in actual applications, the luminous efficiency of most white light LEDs will reduce even before L70 is reached due to the heat generated that the absorption and transformation of the fluorescent material decrease accordingly. The reduction in luminous efficiency then generates more heat. With such cycling mutual effect of heat and efficiency reduction keep going on and on, massive blue light is then inevitably leaked.
On the other hand, with the increasing usage of LEDs, more and more researches and papers about the destructive effect of blue light to human eyes are published to warn that irreversible damages will occur while human eyes are exposed to blue light for more than certain amount or for certain duration.
In view of the above, it has been a common goal and progress of the LED industries and the lighting industries to create a practical, effective and easy-to-use lighting LED structure that can rapidly, accurately and actively detect abnormal status and turn off the white light LED before massive heat is generated and great amount of blue light is emitted, and thus the protection of human eyes and life quality are thus desirably achieved, while at the same time informing the user the need of replacement of lighting device.
The present invention discloses active blue light leakage preventing LED structures to turn off the LED when it reaches its usage life span limit thus avoiding the damage to human from the massive release of blue light.
The present invention provides an active blue light leakage preventing light-emitting diode (LED) structure, comprising: a circuit board having an upper surface; at least one blue LED die fixedly provided on the upper surface and electrically connected to the circuit board; a wavelength conversion layer fixedly provided on and covering a light output surface of the blue LED die; a power source electrically connected to the blue LED die; and a thermal sensor provided adjacent to the blue LED die, wherein when a temperature of the blue LED die rises, the thermal sensor reduces or turns off power supply from the power source to the blue LED die to prevent blue light from leaking out.
Implementation of the present invention at least involves the following inventive steps:
The features and advantages of the present invention are detailed hereinafter with reference to the preferred embodiments. The detailed description is intended to enable a person skilled in the art to gain insight into the technical contents disclosed herein and implement the present invention accordingly. In particular, a person skilled in the art can easily understand the objects and advantages of the present invention by referring to the disclosure of the specification, the claims, and the accompanying drawings.
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The circuit board 10 of the active blue light leakage preventing LED structure 100 comprises an upper surface 11, and the circuit board 10 can be a FRP, ceramic, or flexible circuit board that contains at least one set of circuit path.
At least one blue light LED die 20 is provided on an upper surface 11 of the circuit board 10 and is electrically connected to the circuit board 10. The number or size or even the specification or grade of the said blue light LED die 20 that emits blue light can be chosen as required in actual applications.
The wavelength transformation layer 40, which is provided and set also on the upper surface 11 of the circuit board 10, covers the blue light LED die 20 and the thermal sensor 30. The said wavelength transformation layer 40 can be a phosphor powder layer, a quantum dot layer, or any material layer formed with photoluminescence material.
Further, the phosphor powder layer used as the wavelength transformation layer 40 can be a yellow color phosphor powder layer, a red-green mixed color phosphor powder layer, or an orange-green mixed color phosphor powder layer.
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Wherein the said packaging lens 60 or the said wavelength transformation layer 40 can be glued on the upper surface 11 of the circuit board 10 with a gasket.
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The power source 50 is electrically connected to the blue LED die 20 and serves mainly to provide the electric power needed by the blue LED die 20 during operation.
The thermal sensor 30 is provided adjacent to the blue LED die 20. When the temperature of the blue LED die 20 rises during operation, the wavelength conversion layer loses its intended effect gradually, and the amount of blue light leaking out increases as a result. The thermal sensor 30, therefore, is configured to reduce or turn off power supply from the power source 50 to the blue LED die 20 when detecting a rise in the temperature of the blue LED die 20, thereby preventing blue light from leaking out.
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The embodiments described above are intended only to demonstrate the technical concept and features of the present invention so as to enable a person skilled in the art to understand and implement the contents disclosed herein. It is understood that the disclosed embodiments are not to limit the scope of the present invention. Therefore, all equivalent changes or modifications based on the concept of the present invention should be encompassed by the appended claims.