Surprisingly Affordable Heat Spreader
We ran a somewhat tongue in cheek ad several years ago questioning the use of heat pipes over our patented one piece vapor chamber in heatsink designs. While we believe wholeheartedly in heat pipes for certain applications, Celsia’s one piece heat spreaders offer some compelling benefits.
We began the early work on this design nearly a decade ago. The goal was to meaningfully cost reduce a traditional two piece design while maintaining thermal performance characteristics and adding some unique capabilities. During the course of development, our engineering teams experimented with hundreds of component and manufacturing process combinations to arrive at a device portfolio that has shipped in millions of commercially available products since 2008. It was the first vapor chamber, of any kind, to be used in high performance heatsinks for graphics cards, DRAM memory modules, and notebook computers.
Like heat pipes, our one piece product begins its life as a copper tube, has an internal wick structure attached to the inside walls, moves liquid around the system using capillary, and has lower manufacturing costs. Like traditional two-piece designs, one piece vapor chambers make direct contact with the heat source, have a radial heat flow, and can support high clamping forces.
From large diameter tube stock, a wicking structure is attached to the inside walls using various density and porosity formulations. Then a wafer thin micro-perforated spacer is inserted to aid in vapor flow while enhancing structural rigidity. As with all two phase devices, a liquid is added and the device is vacuum sealed. This process requires no stamping or machining and reduces the number of secondary operations, driving cost down to near parity with heat pipe solutions.
While a one piece vapor chamber heat sink design is almost always a square or rectangle, it has a number of advantages when compared with both two piece designs and heat pipes. These included:
Advantages of One Piece vs. Two Piece Vapor Chambers
- Post production bending in the Z-direction while maintaining nearly all of their thermal transport characteristics.
- Fast and comparatively inexpensive prototype and production costs with quick cycle times and high yield rates.
- Thinner product for space constrained environments – down to 1mm.
Advantages of One Piece Vapor Chambers vs. Heat Pipes
- Ability to make direct contact with the entire heat source, reducing thermal resistance.
- Multi-directional heat spreading versus linear heat transport. This enables more uniform heat distribution into the heat sink and reduces hot spots on the heat source (Tcase temp).
- The surface area can be embossed to reach a recessed heat source.
- Able to be made thinner and wider – as thin as 1mm and as wide as 100mm.
- 3 to 4 times the maximum heat transport capacity.
|Heat Pipe||One Piece VC||Two Piece VC|
|Min/Max Thickness||~2.0mm if flattened||>1.0mm||>2.0mm|
|Maximum Bending Angle||3x diameter||R~10 (inner circle base)||No|
|Shapes: X and Y Direction||Yes – Post Production
|No: Square or Rectangle
|Max Heat Transport Capacity||5 watts @ 2mm
1kw @ 25mm
|10watts @ 1mm
500 watts @ 4mm
|10watts @ 1mm
500 watts @ 4mm
|Allowable Operating Temp.||10 to 150 C||10 to 125 C||10 to 125 C|
|Storage Temperature||-40 to 100 C||-40 to 100 C||-40 to 100 C|
|Storage Humidity (%RH)||5~90%RH||5~90%RH||5~90%RH|
|Life||>100,000 hours||>100,000 hours||>100,000 hours|
|Through Holes||Not Applicable||No||Yes|