Because when the LED lamp operating temperature rises, their life and luminous efficiency are may decrease, and produce a color shift and light failure degree will improve, and for the 200W led Flood light can cause quite a bad influence, so how to LED light bulb in limited space, in the most efficient way to heat, has long been are 200W led Flood light industry research and development design key point.
Generally speaking, LED bulb light the diode in which waste heat, can through the Slug, Board... , and other components of the guide, then emissions to the atmosphere of the surrounding environment, heat transfer in the diode and Slug, Slug and between Board, mainly by heat conduction type, as for the Board transfer to atmospheric environment, it is heat conduction, heat convection and heat radiation three. 200W led Flood light industry in the planning of product thermal design, can be this conduction process cooling analysis, so as to calculate each a link to the heat resistance, and then according to the size of the worse part to improve. To solve this problem is the practice of heat can see effect.
Analysis of heat conduction form solve LED heat dissipation problems
With the improvement of the heat transfer efficiency as an example, we can try to increase through Slug/Board geometric size area, also or direct selects high thermal conductive materials to make cooling element way, in order to reduce this part of the thermal resistance. For the diode and Slug, Slug and between Board because of the size difference and temperature distribution is uneven and derived by the diffusion resistance, is recommended by JianGuoXiang can reduce the area ratio, increase element plate thickness, improve the material itself and strengthen the coefficient of heat conduction, heat convection effect... The level to laid hands on him. Increasing the thickness of the floor is a common practice. When the thickness increases, because the area is greater than that of differences caused by effect can be reduced, heat to vertical direction and horizontal diffusion speed to both sides will tend to be more consistent, so that the diffusion heat resistance the impact of the problem becomes.
If limited by space considerations, plate thickness can no longer increases, the operator may by adding heat pipe... Etc, and strengthen the floor horizontal heat conduction coefficient, in order to shorten the vertical and horizontal heat conduction difference. This means that plate thickness thin, increase its lateral heat conduction coefficient of the high efficiency. Although the thickness increase will reduce the diffusion heat resistance, but relative to also can make one dimensional thermal resistance increase. Operators must be through the experiment and calculation way, try to get a balance between the bottom, in order to find the best thickness. But generally speaking, when the diode and Slug, Slug and Board of the difference between the area, also can have the best thickness increases with the trend.
As for the heat convection, because in addition to the needs of the environment, we must use fan... Etc for forced convection besides, general industry to avoid increase its product cooling element volume and manufacturing cost, usually using natural convection way design. When the Board geometric area is larger, or thermal convection coefficient is higher, the heat convection heat resistance is small. But unfortunately, usually the Board geometric area, heat convection coefficient is relatively worse. So people in the planning LED bulb layout, general will take its Board geometric area and heat convection coefficient multiplication after the maximum value for design.
In addition to the design of the cooling fins, due to the heat from the bottom end to the way of heat dissipation, so the coefficient of heat conduction, heat convection coefficient and the thickness value, will affect the cooling fins of the optimal size. In the general case, when cooling fins thickness, the higher the coefficient of heat conduction, fins the cooling efficiency is better; And in contrast, when the heat convection coefficient is higher, fins the cooling efficiency will be worse. In other words, if the heat convection effect is very good, the cooling fins need and the size of the smaller. So generally adopt natural convective cooling fins usually is tall, and fins and fins between should keep distance would also more wide.
LED bulb heat treatment should be practical application requirement
In addition to the heat conduction and heat convection outside, thermal radiation is also LED bulb cooling is an important mechanism. The effect of heat radiation and material quality of the surface condition. With cooling fins for example, in size and spacing fixed condition, the aluminum surface quality whether there is a polishing, or have been oxidation, for its thermal radiation effect there is a big difference. On the other hand, also because of the heat radiation surface must have temperature difference, and can directly see each other, to heat transfer, so for some style of lamps and lanterns, heat radiation to come loose hot effect, sometimes even better than the other two.
The lamps and lanterns of different design and lighting needs, should the cooling technology will also be different. Like a luminous efficiency, semiconductor material, light source distribution, heat transmission distance, external can come into contact with air environment... And such variables, the design of the cooling element for the lamps and lanterns that have great influence. For instance, if the LED lamp luminous efficiency can be up to 90%, to let the current converted into heat, or reduce the semiconductor material in a higher temperature can still run normally, nature can reduce cooling element for the area of the occupied. "And some lamps and lanterns (such as downlight) will be in a relatively closed space, some (such as reflectoscope) can be directly exposed to air or cold room under the environment." So specific LED bulb heat processing design way, should according to the demand with the situation and decide.