Patent Application
20050174808
The present invention is directed to diode-based light devices, and more particularly, to quick attachment testing and power connections for diode-based light devices.
A variety of light-emitting devices exist that utilize diode-based light sources. For example, such devices utilize light emitting diodes (LEDs) that are configured to emit visible light, infrared (IR) diodes for emitting IR light, and ultraviolet (UV) diodes for emitting UV light.
In light devices that utilize a diode-based light source, the diode may include pins that are connected to electrical wiring for providing power to the diode. Other devices use surface-mounted diodes, in which each diode is affixed to a mounting plate that includes solder pads. Electrical power connections may be soldered onto these pads to provide the LED power. Examples of such surface-mounted LEDs include the LUXEON™ Star LED module in the LUXEON Star/O LED module, which are currently available on the commercial market.
Various types of testing equipment are used for measuring the performance of LED devices. An example is an integrating sphere, which is a small sphere whose interior surface has a white reflective coating. The sphere is connected via fiber optic cable to a compact array spectrometer. Specifically, an LED device is fixed in relation to an opening of the integrating sphere, and light emitted from the LED device reflects the interior surface to the detector. Accordingly, various measurements of the LED device may be made, including luminous flux, wavelength, chromaticity, and spectral distribution.
To ensure the accuracy of measurements made by an integrating sphere, as well as other types of LED measurement devices, the location of the LED during testing must be known to a high degree of precision. Accordingly, a fixture must be used to secure the LED at a known location relative to the testing equipment.
However, it is also desirable to utilize testing equipment, such as the integrating sphere, to perform repeated measurements on multiple LED devices. However, while conducting repeated testing on a large number of LED devices, the process of securely placing each LED device into testing position with conventional fixtures is very time consuming. Also, another problem exists in that a constant emitter junction temperature must be maintained for each of the LED devices being tested in order to obtain accurate results.
Exemplary embodiments of the present invention utilize quick disconnect fixtures capable of securely fixing each of a plurality of diode light sources into position for repeatable testing, while providing thermo-electric cooling (TEC) for maintaining each of the tested diode light sources at a constant emitter junction temperature.
According to an exemplary embodiment, a quick attachment device for placing a diode light source into position for repeatable testing includes a quick attachment module having a fixed location with respect to the repeatable testing position, and a mounting assembly on which each diode light source is mounted during testing. The mounting assembly is operably connected to the quick attachment module via a quick disconnect hinge. The mounting assembly includes a thermo-electric cooling device capable of cooling the diode light source being tested. In this exemplary embodiment, the quick attachment module may include two locating pins to provide a locational transition (LT) fit connection between the quick attachment module and the mounting assembly when diode light sources are moved into the repeatable testing position.
In another exemplary embodiment, the mounting assembly includes a thermistor for detecting a temperature of the mounting assembly. The thermoelectric cooling device may be controlled based upon this detected temperature in order to maintain each of the diode light sources at a constant junction temperature during testing.
According to another exemplary embodiment, the mounting assembly may include a thermally insulating module with two slots, each slot configured to receive a corresponding one of the locating pins in an LT fit connection. The thermally insulating module may be comprised of two modular wear blocks, each of which includes one of the slots for receiving the locating pins.
In further exemplary embodiments, the mounting assembly may include other means of dissipating heat. For example, a heat sink may operably connected to a mounting plate on which each diode light source is mounted during testing. In another exemplary embodiment, an electric fan may be connected to the heat sink.
In an exemplary embodiment, the quick attachment module includes another fastener, e.g., a second quick disconnect hinge, to be engaged with a fastening mechanism on the mounting assembly when the diode light sources are moved into fasting position. Based on the LT fit connection between the two locating pins and the thermally insulating module, exemplary embodiments of the present invention need only two fasteners (or quick disconnect hinges) to securely and accurately place each diode light source in testing position when repeatable testing is being performed for a large number of diode light sources. When modular wear blocks (e.g., made of plastic) are used in the thermally insulating module, any eventual loosening of the LT fit can be eliminated by merely replacing these modular wear blocks.
According to an exemplary embodiment, the mounting assembly may include a low-conductive plate, which becomes positioned between the mounting plate and the quick attachment module when a diode light source is moved into testing position. For example, a low-conductive plate may be fastened to the mounting plate of the mounting assembly. A low-conductance material (e.g., semiconductor material) may cover up electrical pathways to the diode light source that provide power during testing. Thus, when the quick attachment module is comprised of a metallic or other electrically conductive material, the low-conductive plate may help prevent short circuiting or electric shocks during testing.
According to an exemplary embodiment, the low-conductive plate may be a power card that provides power, during testing, to a surface-mounted diode light source whose mounting plate includes a solder pad-type power interface. In such an embodiment, the power card may include solder pad contacts that are adaptable to a relative height differential of the solder pads in the surface-mounted diode light source, thereby maintaining contact with these pads. The power card may further include electrically-insulated electrical pathways connecting each solder pad contact to an external power source connector on the power card. In an exemplary embodiment, the electrical pathways are insulated from the quick attachment module by the low-conductance substrate of the power card. The electrical pathways are further electrical insulated from the mounting plate of the diode light source, e.g., with an insulating electrical tape.
The power card may further include flexible tabs, on which each solder pad contact is disposed. The tabs may allow the contacts to adapt to the height differential between the solder pads of the surface-mounted light source. In such an embodiment, each of these tabs is configured to displace its solder pad contact a suitable distance, using spring-loaded tension, in order to maintain contact with the corresponding solder pad of the surface-mounted diode light source.
Further advances in scope of applicability of the present invention will become apparent from the detailed description provided hereinafter. However, it should be understood that the detailed description and specific embodiments therein, while disclosing exemplary embodiments of the invention, are provided by way of illustration only.
A more complete understanding of the present invention will become apparent in the following description taken in conjunction with the accompanying drawings, wherein:
Exemplary embodiments of the present invention are disclosed in the following description.
The present invention is directed to a device for fixating diode light sources to a specific testing position relative to measurement devices. According to exemplary embodiments, the device has a quick disconnect configuration that allows for the repeated testing of a high number of diode light sources. Furthermore, this fixture device is operable to adjust a junction temperature of each diode light source in order to maintain a constant temperature for all of the light sources being tested.
Exemplary embodiments of the present invention allow for each of the plurality of diode light sources to be quickly attached to the fixture device and moved into testing position. Thus, the fixture device will hereinafter be referred to a “quick attachment device.” However, this term is used for purposes of description only and should not be construed as limiting the present invention in any way.
According to an exemplary embodiment, the quick attachment device includes means for providing power to each of the diode light sources during testing. However, the diode light sources being tested may be of the type utilizing solder pad connections to receive power. In such cases, it is usually required for these connections to be soldered to the solder pads located on the diode light sources, which could be a very time consuming process. Thus, an exemplary embodiment of the present invention includes a diode light source power card that obviates the need for soldering power connections to diode light sources utilizing solder pads.
Although not shown in
Operation of the quick attachment device according to the exemplary embodiments shown in
The quick attachment module 10 includes two quick disconnect hinges 110A and 110B, each of which includes a corresponding one of the locating pins 120A and 120B. These components allow for the mounting assembly 20 to be quickly attached to the quick attachment module 10 according to a locational transition (LT) fit connection between the locating pins 120A and 120B and the slots 232A and 232B of the mounting assembly 20. Each of the quick disconnect hinges 110A and 110B of the quick attachment module 10 are engaged with a corresponding one of fastening mechanisms 234A and 234B on the mounting assembly 20. For example, the length of each of the fastening mechanisms 234A and 234B may be compressed by squeezing the illustrated handles so that the fastening mechanism will fit within the corresponding hinge 110A, 110B.
As shown in
It should be noted that the quick attachment module 10 and mounting assembly 20 may include other types of quick disconnect mechanisms, as will be contemplated by those of ordinary skill in the art. For example, the two quick disconnect hinges 110A and 110B of quick attachment module 10 may be replaced with any type of fixture that includes two locating pins 120A and 120B and two fasteners or latches, capable of quickly being fastened and unfastened with corresponding parts of the mounting assembly 20 during repeated testing. Such configurations may include one quick disconnect hinge, utilized in combination with another type of fastener.
As stated above,
According to an exemplary embodiment, the slots 232A and 232B may be located within a thermally insulating module at the mounting assembly 20. In the exemplary embodiments as shown in
Prolonged repeated testing at diode light sources 30 using the quick attachment device may cause the LT fit connection to loosen, based on the wear on the slot 232A and 232B. Accordingly, the modular wear blocks 230A and 230B may be easily replaced when such loosening occurs. The use of relatively inexpensive materials facilitates the replacement of the modular wear blocks 230A and 230B when needed.
Although the above embodiments describe the locating pins 120A and 120B as having an LT fit connection with the corresponding slots 232A and 232B, it should be noted that the present invention covers other types of fits. The type of connection fit between the locating pins 120A, 120B and slots 232A, 232B may be any one of a location clearance fit, locational interference fit, a press fit, etc. However, this list is not exhaustive, and any other suitable connection fit may be used, as will be contemplated by those of ordinary skill in the art.
The function of the TEC device 260 is to further cool the mounting plate 220 as heat is being generated during testing, in order to maintain a constant junction temperature for the plurality of diode light sources 30. According to an exemplary embodiment, a thermistor (not shown) may be included in the mounting assembly 20 to detect the temperature of the mounting plate 220. For example, the thermistor may be directly attached to the mounting plate 220. Signals from the thermistor may be sent to a control unit (not shown). The control unit may be a processor located somewhere on the quick attachment device or, alternatively, positioned at a remote location. Based on the signals from the thermistor, the control unit may control the operation of the TEC device 260, for example, by controlling the TEC device 260 to turn on and off. The control unit may also be configured to control other operations of the TEC device 260 such as the degree of cooling.
The mounting assembly 20 may further include an electric fan 250 connected to the heat sink 240, as illustrated in
As described above, the low-conductive plate 210 may be positioned on the mounting assembly 20, so as to cover the front of the mounting plate 220. Accordingly, when the quick attachment device is in the closed position, as illustrated in
In such an embodiment, the mounting plate 220 does not have direct contact with the quick attachment module 10. Accordingly, when the quick attachment module 10 and the mounting plate 220 are made of electrically conductive material (e.g., metal), the low-conductive plate 210 protects against potential electric shocks or short circuits during testing of diode light sources 30. However, the use of the low-conductive plate 210 may not always be required, especially in situations where other precautionary measures are taken to protect against electric shock and short circuits.
As shown in
In the exemplary embodiments illustrated by
In addition, various modifications may be made to the embodiments of the quick attachment device shown in
As shown in
The quick attachment device may further include means for providing power to the diode light sources 30 during testing. The power source may be located on the quick attachment device (e.g., a battery pack connected to the mounting assembly). Alternatively, an external source may be used.
Exemplary embodiments of the present invention are directed to means for performing repeated testing on a plurality of diode light sources 30, which is both quick and accurate. Accordingly, it will be advantageous for the power source to be quickly connected to, and disconnected from, each of the diode light sources 30.
Some types of diode light sources 30 are equipped with power interfaces that utilize solder pads. The process of soldering power leads to these solder pads to provide power to the diode light source 30 is time consuming, and may result in exposed power connections creating a possible electrical hazard.
Therefore, in an exemplary embodiment, the non-conductive plate 210 may further be configured as a power supplying device for use with diode light sources 30, whose power interface utilizes solder pads.
In particular,
Referring to
As shown in
The placement of contact pads 213 on flexible tabs 214 allow for the power supply device 210 to compensate for a relative height differential with respect to the solder pads of a diode light source module.
In order for the solder pad contacts 213 of power supply device 210 to remain in contact with the corresponding solder pads 513A and 513B of the diode light source module 500, each of the solder pad contacts 213 are located on one of the flexible tabs 214. Thus, based on this spring-loaded tension of the tabs 214, each tab 214 will be displaced a necessary distance in order for the corresponding solder pad contacts 213 to remain in contact with, and provide power to, the corresponding solder pads 513A and 513B. Thus, the presence of these flexible tabs 214 on the power supply device 210 provide a degree of tolerance with respect to a relative height differential of solder pads 513A and 514A of the diode light source module 500.
As shown in
According to an exemplary embodiment, the power supply device 210 is mounted to the mounting plate 220, e.g., by driving screws through screw holes 211. The location of the screw holes 211 is aligned with the location of corresponding screw holes in the mounting plate 220 at the diode light source module 500 being tested.
According to an exemplary embodiment, the power connections 215 of the power supply device 210 may be electrically insulated. For example, these electrical pathways 215 may be covered by an insulating electrical tape, or other suitable insulating material, on the rear surface of the power supply device 210. Furthermore, the low-conductive material used in substrate 212 will insulate these pathways 215 from any conductive surface in contact with the power supply device's 210 front surface.
Accordingly, when implemented in the mounting assembly 20 of the quick attachment device illustrated in
In the above exemplary embodiments, which are illustrated in
For example, the power supply device described above in connection with
Furthermore, such a power device may be easily adapted to provide a permanent power connection for a diode light source module by soldering the contacts 213 to the corresponding solder pads 513A and 513B. Such a modification may be advantageous when insulation of the power connections to the module 500 is required.
It should be noted that the above-described power supply device 210 may be modified for use with LED devices other than the LUXEON Star and Star/O emitters. According to such modifications, the power supply device 210 may be operable to provide power to LED devices attached to TO-66 power packages, and other types of leaded LED components. These and similar modifications will be readily apparent to those of ordinary skill in the art.
