WO2002019303A1 - Method and apparatus for enhancing led display's performance via thermal management thereof - Google Patents

Method and apparatus for enhancing led display's performance via thermal management thereof Download PDF

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Publication number
WO2002019303A1
WO2002019303A1 PCT/SG2001/000175 SG0100175W WO0219303A1 WO 2002019303 A1 WO2002019303 A1 WO 2002019303A1 SG 0100175 W SG0100175 W SG 0100175W WO 0219303 A1 WO0219303 A1 WO 0219303A1
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WO
WIPO (PCT)
Prior art keywords
optical module
module
led display
led
display system
Prior art date
Application number
PCT/SG2001/000175
Other languages
French (fr)
Inventor
Chinniah Viswanathan
Meng Kong Chan
Yong Lin Huang
Tah Ming Yuan
Fook Weng Ho
Original Assignee
Singapore Technologies Electronics Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Singapore Technologies Electronics Ltd. filed Critical Singapore Technologies Electronics Ltd.
Priority to AU2001284629A priority Critical patent/AU2001284629A1/en
Publication of WO2002019303A1 publication Critical patent/WO2002019303A1/en

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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • G09F9/33—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements being semiconductor devices, e.g. diodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L5/00—Local operating mechanisms for points or track-mounted scotch-blocks; Visible or audible signals; Local operating mechanisms for visible or audible signals
    • B61L5/12—Visible signals
    • B61L5/18—Light signals; Mechanisms associated therewith, e.g. blinders
    • B61L5/1809—Daylight signals
    • B61L5/1854—Mounting and focussing of the light source in a lamp, fixing means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B61—RAILWAYS
    • B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L2207/00—Features of light signals
    • B61L2207/02—Features of light signals using light-emitting diodes [LEDs]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V23/00—Arrangement of electric circuit elements in or on lighting devices
    • F21V23/02—Arrangement of electric circuit elements in or on lighting devices the elements being transformers, impedances or power supply units, e.g. a transformer with a rectifier
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/15—Thermal insulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2111/00—Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00
    • F21W2111/02—Use or application of lighting devices or systems for signalling, marking or indicating, not provided for in codes F21W2102/00 – F21W2107/00 for roads, paths or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • the present invention relates to low power semiconductor devices and the display systems that are made therefrom.
  • the present invention pertains to improved electronic display system is made from Light-Emitting Diodes (LED) for transportation systems.
  • LED Light-Emitting Diodes
  • incandescent or halogen lamps have been the optical sources for such display systems as they are inexpensive and reasonably easy to maintain and operate.
  • display systems employing LED devices have started to replace traditional display systems using incandescent or halogen lamps because the former consume only a fraction of the energy of the latter. For instance, one red LED traffic signal head that contains 196 individual LEDs operates on a 120 Volt ⁇ rcuft consumes less than 10 Watt, as compared with a 150 Watt incandescent lamp it is intended to replace.
  • LEDs have much longer rated lives than the incandescent lamps used in traffic signals systems: LEDs have average rated lives of over 100,000 hours as compared to 8,000 hours rated live of an incandescent traffic lamps. In terms of maintenance and operating costs, LEDs have a distinct advantage over the existing incandescent lamps.
  • LEDs appear to have certain advantages over incandescent lamps, incandescent lamp has a significant edge in terms of cost it cost $2.50 - $3.00 to replace an incandescent lamp, while a red LED head is about $100. Green LED head cost belween 2.5 and 5 times more than the red ones. Across the United States a number of electric utilities and public agencies have offered financial incentives to municipalities to install LED traffic signals with mixed success. The high initial cost appears to be a significant barrier to LED's wider adoption.
  • LEDs are sensitive to temperature changes in two significant ways: actual live and luminous output.
  • Existing LEDs are rated for operating temperatures of 25 degree C; at lower temperature they produce more light and at higher temperature, less. For example, at -40 degree C AllnGaP LEDs have an output that is 192% of the output at 25-degree C; at 55 degree C, the luminous output is 75% of that at 25 degree C.
  • One option LED manufacturers develop is to optimize for operation at higher temperature than those currently designed.
  • Another potential alternative is to vent the signal head or include a heat sink to decease the interior temperature.
  • an improved LED display system is realised that can achieve the expected energy saving and visibility performance consistently without increasing the payback period of the system.
  • the isolation of the optical module minimizes the fluctuation in temperature of the LED devices and hence ensures a greater luminous output from the optical module. As such, the chances of motorists and pedestrians missing the appropriate traffic signals in inclement weather conditions are reduced.
  • the compartmentalization of the power module not only offers better thermal management of the LED display system but allows upgrade of the transformer without the need to retire the optical module. It follows that the present invention permits the LED display system to meet ever stringent energy efficient standards and yet retaining its initial investment.
  • Rg. 1 is a perspective elevational view of an embodiment of a LED display employed in a traffic light module.
  • Rg. 2 is a side elevational plan view of the embodiment in g. 1 highlighting the segregation of the optical and power modules.
  • Rg. 3 is a exploded, perspective elevational view of the components of a traffic light module incorporating the present invention.
  • the present invention seals the optical and power modules
  • Patent No. 6,036,336 where the LED display head is exposed to ambient temperature, the present invention is more likely to achieve the expected rated live and luminous output.
  • Fig. 1 is a perspective elevational view of an embodiment of a LED display employed in a traffic light head.
  • a LED display head 5 comprises at least one protective cover 2; at least one optical board 6 and at least one optical module cover 8.
  • the protective cover 2 can be made of any synthetic material that is transparent In the preferred embodiment of the present invention, the protective cover 2 is made of clear, dirt and scratch resistant polycarbonate material.
  • the optical board 6 can be made of any surface mount material or similar substrate. In the preferred embodiment of the present invention, the optical board 6 is a printed circuit board made from FR4 material and having a plurality of LED devices 38 inserted through said board.
  • the optical module 5 is sealed with the cover 8; in the preferred embodiment of the present invention, the optical module cover is made from polycarbonate material.
  • the power module is shown only partially with a power module cover 12 coupled to the optical module. Details of the power module will be elaborated further below in connection with the description of Rgs 2 and 3 respectively.
  • Rg. 2 is a side elevational plan view of the embodiment in Rg. 1 highlighting the segregation of the optical module 9 and the power module 15 with a plurality of spacers 40.
  • Prior art LED signal heads integrate the optical module with the power module as manufacturers of LED traffic signal systems did not appreciate the effects of temperature have on low-power and low-current semiconductor devices such as LEDs. As mentioned briefly in the background section above, the luminous output of LEDs changes with temperature: the lower the temperature, the higher the luminous output and vice versa. It was therefore not surprising that few of the LED signals heads in production approached the performance benchmarks of the prototype LED signal heads.
  • the LED optical head 5 of the present invention comprises separate optical module 9 and power module 15. Furthermore, the optical module 9 isolates the LED board 6 from the environment by encasing it with the protective cover 2 and the optical module cover 8. A plurality of legs 42 also raise the LED board 6 away from the optical module cover 8. Disposed on the surface opposing the LED board are a plurality of spacers 40 for coupling detachably the optical module 9 with the power module 15.
  • the power module 15 comprises at least one transformer (not shown in Rg. 2 but in Rg.3) that is encased with a power module cover 12 and a power module housing 24.
  • a power cord 44 provides sources of electric power to the power module 15. Although the power module emits comparatively large amounts of heat, the effects it has on the optical module 9 are minimized because of the isolation of the two modules and the sealing of the two modules.
  • Rg. 3 is an exploded, perspective elevational view of the components of a LED signal head 5 incorporating the present invention.
  • the LED signal head 5 comprises two distinct modules: the optical module 9 and power module 15, respectively.
  • the optical module 9 further comprises the protective cover 2, an O-ring 4, the LED board 6 and the optical module cover 8.
  • the optical module 9 is sealed such that it is weather proof against moisture, air and dust by encapsulating the LED board 6 with the protective cover 2 and the optical module cover 8 with the O-ring 4.
  • Power to the LED board 6 is provided by an optical power cord 10 that terminates at the optical module cover 8. The sealing of the optical module minimizes fluctuation of operating temperature of the LED.
  • the immediate benefit is the greater luminous output of the LEDs - a key factor in determining the visibility of LED traffic signal h inclement weather.
  • LED traffic signal do not suffer from sun- phantom effect Sun-phantom effect arises when reflection of the sun on the reflectors of the traffic signals using incandescent lamps creates an illusion that the traffic light is activated when it is not
  • a secondary and long term advantage is the ability of the optical module to achieve the rated live - another key financial consideration h determining the acceptance and also payback period of adopting LED display for traffic signal systems.
  • the stability h temperature within the optical module 9 also minimizes condensation therein irrespective of any fluctuation in ambient temperature.
  • the power module 15 of the LED signal head 5 further comprises the power module cover 12, a membrane 14, insulators 16, a transformer 20, an optional washer 18, a driver board 22 and a power module housing 24.
  • the power module 15 is sealed securely with the membrane 14. Power to the power module 15 is provided by the power cord 26 via the driver board 22.
  • the power module of the present invention is segregated from tiie optical module 9 in order to reduce the thermal toad the LED board 6 is subjected.
  • One of the major advantages of having a separate power module is the ability of cities and or municipalities to upgrade the power module without retiring the optical module to meet ever stringent energy efficiency regulations such as the harmonic current emissions standards in major industrialised countries.
  • the LED signal head of the present invention is adapted for replacing existing traffic signals using incandescent or halogen lamps. Furthermore, the replacement can be accomplished in a piece meal fashion: for instance, in view of the higher costs of green LED signal heads, some cities or municipalities may elect to replace the red traffic signals initially before deciding on those for amber and green traffic signals.
  • the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are, therefore, to be embraced therein.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Traffic Control Systems (AREA)
  • Led Device Packages (AREA)

Abstract

An LED display system including an optical module (9) and a power module (15), said optical module comprising at least one LED board (6), at leat one protective cover (2), at least one optical module cover (8) forming a seal for encapsulating said optical module against fluctuation in operating temperature within said module, a spacer arrangement (40) interposed between said optical module and said power module to minimise thermal effects of the power module.

Description

METHOD AND APPRATUS FOR ENHANCING LED DISPLAY'S PERFORMANCE VIA THERMAL MANAGEMENT THEREOF
FIELD OF THE INVENTION
The present invention relates to low power semiconductor devices and the display systems that are made therefrom. In particular, the present invention pertains to improved electronic display system is made from Light-Emitting Diodes (LED) for transportation systems.
BACKGROUND OF THE INVENTION
Motorists and pedestrians have been relying on optical display systems such as signage or traffic lights for managing and directing flow of automobiles or humans for decades. Hitherto, incandescent or halogen lamps have been the optical sources for such display systems as they are inexpensive and reasonably easy to maintain and operate. Since the middle 1990s, display systems employing LED devices have started to replace traditional display systems using incandescent or halogen lamps because the former consume only a fraction of the energy of the latter. For instance, one red LED traffic signal head that contains 196 individual LEDs operates on a 120 Volt άrcuft consumes less than 10 Watt, as compared with a 150 Watt incandescent lamp it is intended to replace. Published estimates of the energy savings that can be achieved due to the replacement of a red signal head with an LED unit range from 82% to 93%. See, Optimizing the Design and Use of Light- Emitting Diodes for Visually Critical Applications Transportation and Architecture, Lighting Research Center, Rensselaer Polytechnic Institute; November 1999.
LEDs have much longer rated lives than the incandescent lamps used in traffic signals systems: LEDs have average rated lives of over 100,000 hours as compared to 8,000 hours rated live of an incandescent traffic lamps. In terms of maintenance and operating costs, LEDs have a distinct advantage over the existing incandescent lamps.
Although LEDs appear to have certain advantages over incandescent lamps, incandescent lamp has a significant edge in terms of cost it cost $2.50 - $3.00 to replace an incandescent lamp, while a red LED head is about $100. Green LED head cost belween 2.5 and 5 times more than the red ones. Across the United States a number of electric utilities and public agencies have offered financial incentives to municipalities to install LED traffic signals with mixed success. The high initial cost appears to be a significant barrier to LED's wider adoption.
A further key to the possible wider acceptance of LED traffic signal system is the ability of the LED industry to address the visibility issue. LEDs are sensitive to temperature changes in two significant ways: actual live and luminous output. Existing LEDs are rated for operating temperatures of 25 degree C; at lower temperature they produce more light and at higher temperature, less. For example, at -40 degree C AllnGaP LEDs have an output that is 192% of the output at 25-degree C; at 55 degree C, the luminous output is 75% of that at 25 degree C. One option LED manufacturers develop is to optimize for operation at higher temperature than those currently designed. Another potential alternative is to vent the signal head or include a heat sink to decease the interior temperature.
OBJECT OF THE INVENTION
It is an object of the present invention to enhance the performance of LED display system without imposing any physical or electrical overhead to LED traffic signal system.
It is another object of the present invention to reduce the fluctuation of temperature within the LED traffic signal heads in order for the LED to achieve optimal visibility criteria.
It is yet another object of the present invention to isolate the optical module from the power module of LED traffic signal heads in order to prolong the rated live of LED optical module.
It is a further object of the present invention to segregate the optical module from the power module of LED traffic signal heads such that the power module can be replaced with more energy efficient transformers without retiring the optical module.
It is an additional object of the present invention to seal the optical module of a LED traffic signal head for all weather conditions and attaining superior performance. SUMMARY OF THE INVENTION
By segregating the optical and power modules of a LED traffic signal head and sealing each against all weather conditions, an improved LED display system is realised that can achieve the expected energy saving and visibility performance consistently without increasing the payback period of the system. The isolation of the optical module minimizes the fluctuation in temperature of the LED devices and hence ensures a greater luminous output from the optical module. As such, the chances of motorists and pedestrians missing the appropriate traffic signals in inclement weather conditions are reduced. The compartmentalization of the power module not only offers better thermal management of the LED display system but allows upgrade of the transformer without the need to retire the optical module. It follows that the present invention permits the LED display system to meet ever stringent energy efficient standards and yet retaining its initial investment.
BRIEF DESCRIPTION OF THE DRAWINGS
Rg. 1 is a perspective elevational view of an embodiment of a LED display employed in a traffic light module.
Rg. 2 is a side elevational plan view of the embodiment in g. 1 highlighting the segregation of the optical and power modules.
Rg. 3 is a exploded, perspective elevational view of the components of a traffic light module incorporating the present invention. DETAILED DESCRIPTION OF THE INVENTION
Central to the present invention is the concept of improving the thermal management of LED display by separating the optical module from the power module. Unlike prior art disclosed in U.S. Patent No. 5,636,057 where the optical and power module are integrated as one unitary head, the present invention is less susceptible to fluctuation of internal temperature of the optical module.
Furthermore, the present invention seals the optical and power modules
• against all weather conditions. In contrast with prior art such as that taught in U.S.
Patent No. 6,036,336 where the LED display head is exposed to ambient temperature, the present invention is more likely to achieve the expected rated live and luminous output.
PREFERRED EMBODIMENT OF THE INVENTION
Fig. 1 is a perspective elevational view of an embodiment of a LED display employed in a traffic light head. A LED display head 5 comprises at least one protective cover 2; at least one optical board 6 and at least one optical module cover 8. The protective cover 2 can be made of any synthetic material that is transparent In the preferred embodiment of the present invention, the protective cover 2 is made of clear, dirt and scratch resistant polycarbonate material. The optical board 6 can be made of any surface mount material or similar substrate. In the preferred embodiment of the present invention, the optical board 6 is a printed circuit board made from FR4 material and having a plurality of LED devices 38 inserted through said board. Rnally, the optical module 5 is sealed with the cover 8; in the preferred embodiment of the present invention, the optical module cover is made from polycarbonate material. The power module is shown only partially with a power module cover 12 coupled to the optical module. Details of the power module will be elaborated further below in connection with the description of Rgs 2 and 3 respectively.
Rg. 2 is a side elevational plan view of the embodiment in Rg. 1 highlighting the segregation of the optical module 9 and the power module 15 with a plurality of spacers 40. Prior art LED signal heads integrate the optical module with the power module as manufacturers of LED traffic signal systems did not appreciate the effects of temperature have on low-power and low-current semiconductor devices such as LEDs. As mentioned briefly in the background section above, the luminous output of LEDs changes with temperature: the lower the temperature, the higher the luminous output and vice versa. It was therefore not surprising that few of the LED signals heads in production approached the performance benchmarks of the prototype LED signal heads.
Referring again to Rg. 2, the LED optical head 5 of the present invention comprises separate optical module 9 and power module 15. Furthermore, the optical module 9 isolates the LED board 6 from the environment by encasing it with the protective cover 2 and the optical module cover 8. A plurality of legs 42 also raise the LED board 6 away from the optical module cover 8. Disposed on the surface opposing the LED board are a plurality of spacers 40 for coupling detachably the optical module 9 with the power module 15. Again in Rg. 2, the power module 15 comprises at least one transformer (not shown in Rg. 2 but in Rg.3) that is encased with a power module cover 12 and a power module housing 24. A power cord 44 provides sources of electric power to the power module 15. Although the power module emits comparatively large amounts of heat, the effects it has on the optical module 9 are minimized because of the isolation of the two modules and the sealing of the two modules.
Rg. 3 is an exploded, perspective elevational view of the components of a LED signal head 5 incorporating the present invention. As mentioned above, the LED signal head 5 comprises two distinct modules: the optical module 9 and power module 15, respectively. The optical module 9 further comprises the protective cover 2, an O-ring 4, the LED board 6 and the optical module cover 8. The optical module 9 is sealed such that it is weather proof against moisture, air and dust by encapsulating the LED board 6 with the protective cover 2 and the optical module cover 8 with the O-ring 4. Power to the LED board 6 is provided by an optical power cord 10 that terminates at the optical module cover 8. The sealing of the optical module minimizes fluctuation of operating temperature of the LED. The immediate benefit is the greater luminous output of the LEDs - a key factor in determining the visibility of LED traffic signal h inclement weather. As compared with traffic signals employing either incandescent or halogen lamps, LED traffic signal do not suffer from sun- phantom effect Sun-phantom effect arises when reflection of the sun on the reflectors of the traffic signals using incandescent lamps creates an illusion that the traffic light is activated when it is not A secondary and long term advantage is the ability of the optical module to achieve the rated live - another key financial consideration h determining the acceptance and also payback period of adopting LED display for traffic signal systems. Rnally, the stability h temperature within the optical module 9 also minimizes condensation therein irrespective of any fluctuation in ambient temperature.
Referring again to Rg.3, the power module 15 of the LED signal head 5 further comprises the power module cover 12, a membrane 14, insulators 16, a transformer 20, an optional washer 18, a driver board 22 and a power module housing 24. In the preferred embodiment of the present invention, the power module 15 is sealed securely with the membrane 14. Power to the power module 15 is provided by the power cord 26 via the driver board 22. Unfike prior art LED signal heads, the power module of the present invention is segregated from tiie optical module 9 in order to reduce the thermal toad the LED board 6 is subjected. One of the major advantages of having a separate power module is the ability of cities and or municipalities to upgrade the power module without retiring the optical module to meet ever stringent energy efficiency regulations such as the harmonic current emissions standards in major industrialised countries.
It should be understood by one skilled in the art that the LED signal head of the present invention is adapted for replacing existing traffic signals using incandescent or halogen lamps. Furthermore, the replacement can be accomplished in a piece meal fashion: for instance, in view of the higher costs of green LED signal heads, some cities or municipalities may elect to replace the red traffic signals initially before deciding on those for amber and green traffic signals. The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are, therefore, to be embraced therein.

Claims

We claim: 1. In a LED display system including at least an optical module and a power module for displaying signals by providing power source to said system, an apparatus for enhancing the performance of said LED display system, said apparatus comprising:
a seal for encapsulating said optical module against fluctuation h operating temperature within said module, said module further comprising at least one LED board, at least one protective cover and at least one optical module coven and
a spacer arrangement interposed between said optical module and said power module for further minimising the effects of thermal toad generated from said power module on said optical module,
whereby said apparatus maximizes tiie luminous output from said optical module while achieving the rated live of said optical module.
2. An apparatus for enhancing the performance of LED display system wherein said power module is sealed to isolate the heat emission therefrom.
3. An apparatus for enhancing the performance of LED display system wherein said spacer arrangement comprises an extension of said optical module cover.
4. An apparatus for enhancing the performance of LED display system wherein said spacer arrangement comprises an extension of said power module.
5. In a LED display system including at least an optical module and a power module for displaying signals by providing power source to said system, a method for enhancing the performance of said LED display system, said method comprising the steps of: sealing said optical module against fluctuation in operating temperature within said module, said module further comprising at least one LED board, at least one protective cover and at least one optical module cover; and
providing a spacer arrangement between said optical module and said power module for further minimising the effects of thermal load generated from said power module on said optical module,
whereby said method maximizes the luminous output from said optical module while achieving the rated live of said optical module.
5. A method for enhancing the performance of LED display system wherein said power module is sealed to isolate the thermal load generated therefrom.
6. A method for enhancing the performance of LED display system wherein said spacer arrangement comprises an extension of said optical module cover.
7. A method for enhancing the performance of LED display system wherein said spacer arrangement comprises an extension of said power module.
PCT/SG2001/000175 2000-09-01 2001-08-31 Method and apparatus for enhancing led display's performance via thermal management thereof WO2002019303A1 (en)

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SG200005006A SG104261A1 (en) 2000-09-01 2000-09-01 Method and apparatus for enhancing led display's performance via thermal management thereof

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Cited By (7)

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WO2003098574A1 (en) * 2002-05-18 2003-11-27 Obshestvo S Ogranichennoi Otvetstvennostiu 'va Instruments' Optical signal device
FR2875632A1 (en) * 2004-09-23 2006-03-24 Farhad Shadabi Traffic signal has housing containing LEDs of different colours to show stop, warning and direction arrows in addition to speed limits
EP1711739A1 (en) * 2004-01-28 2006-10-18 Tir Systems Ltd. Directly viewable luminaire
EP2191197A1 (en) * 2007-08-27 2010-06-02 Dialight Corporation Led based hazardous location light with versatile mounting configurations
WO2012039786A1 (en) * 2010-09-24 2012-03-29 Cree, Inc. Led lamp
DE102017203203A1 (en) 2017-02-28 2018-08-30 Zumtobel Lighting Gmbh Gear tray for light
CN113593438A (en) * 2021-08-09 2021-11-02 路特迩科技(杭州)有限公司 All-weather variable information signboard based on liquid crystal display screen and safety management method thereof

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US5785418A (en) * 1996-06-27 1998-07-28 Hochstein; Peter A. Thermally protected LED array
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WO2000036336A1 (en) * 1998-12-17 2000-06-22 Koninklijke Philips Electronics N.V. Light engine
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US5264997A (en) * 1992-03-04 1993-11-23 Dominion Automotive Industries Corp. Sealed, inductively powered lamp assembly
US5785418A (en) * 1996-06-27 1998-07-28 Hochstein; Peter A. Thermally protected LED array
JP2000149610A (en) * 1998-11-17 2000-05-30 Transportation Systems Electric Corp Multiple lamp color light signal
WO2000036336A1 (en) * 1998-12-17 2000-06-22 Koninklijke Philips Electronics N.V. Light engine
US6161910A (en) * 1999-12-14 2000-12-19 Aerospace Lighting Corporation LED reading light

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003098574A1 (en) * 2002-05-18 2003-11-27 Obshestvo S Ogranichennoi Otvetstvennostiu 'va Instruments' Optical signal device
EP1711739A1 (en) * 2004-01-28 2006-10-18 Tir Systems Ltd. Directly viewable luminaire
EP1711739A4 (en) * 2004-01-28 2008-07-23 Tir Technology Lp Directly viewable luminaire
US7654703B2 (en) 2004-01-28 2010-02-02 Koninklijke Philips Electronics, N.V. Directly viewable luminaire
FR2875632A1 (en) * 2004-09-23 2006-03-24 Farhad Shadabi Traffic signal has housing containing LEDs of different colours to show stop, warning and direction arrows in addition to speed limits
EP2191197A4 (en) * 2007-08-27 2013-01-09 Dialight Corp Led based hazardous location light with versatile mounting configurations
EP2191197A1 (en) * 2007-08-27 2010-06-02 Dialight Corporation Led based hazardous location light with versatile mounting configurations
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