Patent Application
20240295802
The present invention is directed to a system for cooling a laser phosphor wheel, and more particularly to a hermetically sealed, compact, closed loop, aerodynamic cooling and mounting system for a laser phosphor wheel.
A laser phosphor system consists of a rotating wheel with an annular strip of phosphor glued onto it using an adhesive. A lens focuses a laser spot on the phosphor which results in increased temperature that can deteriorate performance of the phosphor.
It is known to blow air perpendicular to the wheel for impingement cooling to maintain the temperature of the phosphor below a threshold value. In such systems, the air is recirculated in a closed system using a fan and is cooled using heat pipes. Existing designs typically require multiple fans due to high pressure losses because of the flow path design and need for high air flow rate to provide adequate cooling. The high flow rate and multiple fans lead to high noise levels as well as consuming significant space.
The following prior art is relevant to this specification: U.S. Pat. No. 7,841,721B2: Projector with a sealed structure having an air-circulation path; JP6261061B2: Cooling structure of illumination optical system and projection display device; WO2021116206A1: A laser reflection unit; U.S. Pat. No. 10,303,046: Projector with hermetic housing and air guide wall therein; U.S. Pat. No. 8,845,134B2: Cooling system for light emitting device and light emitting device using the same; U.S. Pat. No. 10,845,686: Phosphor wheel, and phosphor wheel device, light conversion unit, and projection display apparatus, each provided with phosphor wheel.
It is an aspect of the present invention to provide a system for cooling a laser phosphor wheel that addresses the problem of high pressure loss and need of multiple fans.
In an embodiment, a cooling and mounting system is provided for a laser phosphor wheel system and optical elements which is compact and aerodynamic in shape. In one aspect, the cooling and mounting system ensures high efficiency cooling near the optical elements notwithstanding only a small gap between the laser phosphor wheel and the optical elements, as well as low power consumption which enables use of a single small sized fan, along with the optimized flow path for compactness.
In an aspect, the system for cooling the laser phosphor wheel comprises a conduit surrounding the laser phosphor wheel that is oriented to direct a flow of air tangential to rotation of the laser phosphor wheel for absorbing heat therefrom, and at least one heat pipe passing through the conduit for extracting and dissipating heat absorbed by the flow of air.
In another aspect, a lens seat is provided that allows for cooling of the gap between the wheel and the optical elements.
In another aspect, the system is hermetically sealed for closed loop cooling wherein air blown onto the laser phosphor wheel is recirculated back into the fan after cooling via one or more heat pipes.
These together with other aspects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.
With reference to
At least one heat pipe assembly 145 is provided comprising at least one heat pipe 147 that passes through the conduit 120 for extracting heat absorbed from the phosphor wheel 110 by the flow of air, and dissipating the heat externally of the enclosure 115 via cooling fins 150 in the condenser section to improve heat transfer. An additional fan may also be deployed in the condenser section to further improve heat transfer. The enclosure air path around the phosphor wheel 110 follows the circular shape of the wheel so as to occupy minimal space and be aerodynamic in nature to lower pressure losses. The system 100 is hermetically sealed for closed loop cooling such that air blown onto the laser phosphor wheel 110 is recirculated back into the 130 fan after cooling via the one or more heat pipe 145 assemblies.
A lens seat 165 is provided for housing an optical lens 175 that directs light from a laser (not shown) onto an annular strip of phosphor 170 glued to the phosphor wheel 110, and allows for a jacket of air around the lens seat 165 to cool the small gap 180 between the wheel and the lens 175 and adjacent to the hotspot on the wheel where the laser is focused.
The flow direction from the recirculating fan 130 can be either along the direction of fan rotation (co-rotating) or against (contra-rotating), as shown by arrows 185 and 190, respectively.
In the co-rotating configuration (arrows 185), the air flows from supply channel 135 across the wheel 110 to return channel 140 so that the direction of flow impinging on the wheel is along the direction of rotation of the wheel.
In the contra-rotating configuration (arrows 190), the air flows from supply channel 140 across the wheel 110 to return channel 135 so that the direction of flow impinging on the wheel 110 is opposite to the direction of rotation of the wheel.
The one or more heat pipe assemblies 145 can be placed in the path of both or either of the supply and return channels 135, 140 or around the phosphor wheel 110 (
In
In
The various embodiments described above and shown in
As shown in the drawings, one or more heat pipe assemblies 145 may be provided, each having one or more heat pipes 147 and a plurality of fins 150. Thus, although the illustrated embodiments show heat pipe assemblies 145 each having three heat pipes 147, it is contemplated that each heat pipe assembly 145 can include a single heat pipe a47, two heat pipes 147 or more than three heat pipes 147. Also, although,
The many features and advantages of the invention are apparent from the detailed specification and, thus, it is intended by the appended claims to cover all such features and advantages of the invention that fall within the true spirit and scope of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
