WO2005014240A1

WO2005014240A1 - Micro-assembly and test station applied for the chip and bar tester application

Info

Publication number: WO2005014240A1
Application number: PCT/CA2004/001492
Authority: WO
Inventors: Jean-Bernard Dambrin; Nicolas Pelletier; Stéphane PROVOST
Original assignee: MINDREADY SOLUTIONS Inc
Current assignee: MINDREADY SOLUTIONS Inc
Priority date: 2003-08-11
Filing date: 2004-08-11
Publication date: 2005-02-17
Anticipated expiration: 2006-02-11

Abstract

Manipulator for use in the field of robotics are currently limited in their range of movements. A manipulator (10) to enable a wider range of movements comprises a first positioning member (11) having a free end (117) and a lower positioning resolution, and a second positioning member (22) mounted on the free end of the first positioning member and having a higher positioning resolution. In operation, the first positioning member provides for coarser positional adjustment while the second positioning member provides for finer positional adjustment so that the second positioning member mounted on the free end of the first positioning member improves the positioning resolution of the manipulator from the lower positioning resolution to the higher positioning resolution. A corresponding method of improving a positioning resolution of a manipulator with a first positioning member (11) having a free end (117) and a first positioning resolution, comprises mounting on the free end of the first positioning member a second positioning member (22) having a second positioning resolution higher than the first positioning resolution.

Description

MICRO-ASSEMBLY_.AND TEST STATION APPLIED FOR THE CHIP AND BAR TESTER APPLICATION

FIELD OF THE INVENTION

[0001] The present invention relates to the field of robotics. More precisely but not exclusively, the present invention is concerned with the field of robotics applied to micro-assembly and test station system.

BACKGROUND OF THE INVENTION

[0002] Industrial robots are well known and currently used to perform repetitive tasks in many industrial or manufacturing processes.

[0003] However, many industrial and manufacturing processes require high positioning resolution. Industrial robots with high positioning resolution are not only expensive but sometimes still have too low a positioning resolution.

[0004] Micro-robots using piezoelectric elements are known to reach positioning resolution in the order of the micron. Although micro-robots are efficient to perform small-range movements, they are incapable of performing large-range movements.

[0005] Accordingly, there is a need for a manipulator capable of performing, in combination, the large-range movements of an industrial robot and the small- range movements of a micro-robot.

SUMMARY OF THE INVENTION [0006] The present invention relates to a manipulator having a positioning resolution, comprising: a first positioning member having a free end and a lower positioning resolution; and a second positioning member mounted on the free end of the first positioning member and having a higher positioning resolution. In operation, the first positioning member provides for coarser positional adjustment while the second positioning member provides for finer positional adjustment so that the second positioning member mounted on the free end of the first positioning member improves the positioning resolution of the manipulator from the lower positioning resolution to the higher positioning resolution.

[0007] The present invention also relates to a method of improving a positioning resolution of a manipulator with a first positioning member having a free end and a first positioning resolution, comprising mounting on the free end of the first positioning member a second positioning member having a second positioning resolution higher than the first positioning resolution whereby, in operation, the first positioning member provides for coarser positional adjustment while the second positioning member provides for finer positional adjustment so that the second positioning member mounted on the free end of the first positioning member improves the positioning resolution of the manipulator from the first positioning resolution to the second positioning resolution.

[0008] Also in accordance with the present invention, there is provided a method for positioning an object by means of the above described manipulator, comprising: performing a coarser positioning of the object using the first positioning member having a lower positioning resolution; and performing a finer positioning of the manipulator comprising: mounting a light detector on the object using the second positioning member mounted on the free end of the first positioning member and having a finer positioning resolution.

[0009] Further in accordance with the present invention, there is provided a method for performing a Farfield test on an optical device transmitting light along an optical axis using the above described second positioning member; controlling the first and second positioning members to cause rotation of the light detector about two axes situated in a plane generally perpendicular to the optical axis; and measuring at different angular positions of the light detector about the two axes a Farfield distribution of the light transmitted along the optical axis by the optical device.

[0010] The present invention is still further concerned with a method for testing light output characteristics of an optical device using the above described manipulator, comprising: providing a vision system; providing an optical detector; performing a first scan by displacing the vision system through the first positioning member to determine a rough location of the optical device; moving the optical detector to the rough location using the first positioning member; and measuring the light output characteristics of the optical device through the optical detector manipulated through the second positioning member.

[0011] Finally, the present invention relates to a method for measuring light output characteristics of an optical device, comprising: mounting an optical detector on a micro-robot; operating the micro-robot to repeatedly execute a plurality of orbits of the optical detector in order to measure light output characteristics of the optical device; wherein operating the micro-robot comprises measuring light output characteristics of a current orbit and determining the position of a subsequent orbit using the light output characteristics of the current orbit.

[0012] The foregoing and other objects, advantages and features of the present invention will become more apparent upon reading of the following non- restrictive description of an illustrative embodiment thereof, given by way of example only with reference to the accompanying drawings:

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a front, perspective view of a high precision manipulator including features in accordance with the illustrative embodiment of the present invention; [0014] Figure 2 is a side, perspective view of the high precision manipulator of Figure 1 ;

[0015] Figure 3 is a perspective view of a test assembly of the high precision manipulator of Figures 1 and 2, equipped with sensors;

[0016] Figure 4 is a perspective view of a control station for the high precision manipulator of Figures 1 and 2;

[0017] Figure 5 illustrates a Farfield test console;

[0018] Figure 6 illustrates an infrared beam detection console;

[0019] Figure 7 illustrates a 3D curve, real time scan of a light beam using quartz; and

[0020] Figure 8 is a Light Voltage Intensity (LVI) test console.

[0021] It will be noted that throughout the appended drawings, like elements are identified by like reference numerals.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT

[0022] In the following specification, the illustrative embodiment of the present invention will be described in relation to a high precision manipulator, for example a high precision manipulator robot. The present invention could equally be applied to many other types of "manipulators".

[0023] Also, this illustrative embodiment of the present invention will be described in relation to the use of the high precision manipulator for bar (for example a Germanium or Silicon bar forming a junction in semiconductor, or a crystal in certain lasers) and chip testers in the optoelectronic industry. However, it should be kept in mind that the high precision manipulator could also be used for various other applications, for example in the telecommunication or medical industry. [0024] Referring to Figures 1 and 2, the high precision manipulator 10 comprises an industrial robot 11. Still referring to Figures 1 and 2, the industrial robot 11 comprises a stationary base 12 resting on the top face of a table or other platform 13. Table 13 can be movable both horizontally and vertically as indicated by the orthogonal axes 14.

[0025] The industrial robot 11 further comprises an articulated arm 112 formed by arm sections 15, 16, 17 and 117 mounted on the stationary base 12. More specifically, the horizontal arm section 15 has a proximal end pivotally mounted on top of the stationary base 12 about a vertical pivot (not shown). Arm section 16 has a proximal end pivotally mounted on the distal end of arm section 15 through a horizontal pivot 18. Arm section 17 has a proximal end pivotally mounted on the distal end of arm section 16 through a horizontal pivot 19. It should further be mentioned that the distal end of arm section 17 comprises a pair of laterally opposite, flat, parallel spaced apart brackets 20 and 21. Finally, arm section 117 is pivotally mounted between the brackets 20 and 21 of arm section 17 through a horizontal pivot 23.

[0026] Those of ordinary skill in the art will understand that the arm sections 15, 16, 17 and 117 are motorized under the control of a computerized control station 24 (see Figure 4) in order to perform the desired task.

[0027] As a non-limitative example, the industrial robot 11 can be a 5 or 6-axis robot commercialized under the trademark Fanuc™. Those of ordinary skill in the art will appreciate that a 5 or 6-axis Fanuc™ robot is adequate to cover an area of 600x600 mm.

[0028] Industrial robots are otherwise well known to those of ordinary skill in the art and, accordingly, will not be further described in the present specification.

[0029] Still referring to Figures 1 and 2, the high precision manipulator 10 comprises a micro-robot 22 pivotally mounted on the distal end of the arm 117 through a motorized vertical pivot (not shown). Those of ordinary skill in the art will understand that the micro-robot 22 is motorized to rotate about this vertical pivot under the control of the computerized control station 24 (see Figure 4) in order to perform the desired task.

[0030] As a non-limitative example, the micro-robot 22 can be the P-611 NanoCube™ manufactured and commercialized by the Pl-Polytec Group. The P- 611 Nanocube™ is a closed-loop, multi-axis Piezo-NanoPositioning system having a 100 x 100 x 100 μm, XYZ tri-axial positioning and scanning range and coming in an extremely compact package of only 44 x 44 x 44 mm. Equipped with a zero-stiction, zero-friction guiding system, the NanoCube™ provides motion with ultra-high resolution and settling times of only a few milliseconds.

[0031] The P-611 NanoPositioners are equipped with low-voltage piezoelectric drives (0 to 100 V) integrated into a sophisticated flexure guiding system. The force exerted by the piezoelectric drives pushes a multi-flexure parallelogram via an integrated motion amplifier. The flexures are FEA (finite element analysis) modeled for zero-stiction and zero-friction, ultra-high resolution and exceptional guiding precision. Integrated strain gauge position feedback sensors provide nanometer-scale resolution in closed-loop operation (with PI control electronics).

[0032] Micro-robots are otherwise well known to those of ordinary skill in the art and, accordingly, will not be further described in the present specification.

[0033] In operation, the industrial robot 11 will provide for coarser positional adjustment while the micro-robot 22 will provide for finer positional adjustment. In this manner, the industrial robot 11 will ensure pick-up and positioning capability of the high precision manipulator 10 while the micro-robot 22 will improve the i positional accuracy of the overall high precision manipulator 10.

[0034] Thanks to a dedicated software in the adapted computerized control station 24 of Figure 4, the high precision manipulator 10 can be used to perform very position-accurate tasks like, without limitation, alignment, measurement, test, manipulation, etc., for example, not only in the field of bar and chip testers in the optoelectronic industry but also in many other fields including the telecommunication and medical industries. [0035] This type of dedicated software and adapted computerized control station 24 are well known to those of ordinary skill in the art and will not be further described in the present specification. For example, the control station 24 may comprise a computer, a Fanuc™ controller, a PI NanoCube™ controller, etc.

[0036] Bar or chip tester system

[0037] In a non-limitative example of bar or chip tester system:

- The industrial robot 11 is a 5 or 6-axis robot commercialized by Fanuc*™*, and capable of covering an area of 600x600 mm.

- The micro-robot 22 is a P-611 NanoCube™ manufactured and commercialized by the Pl-Polytec Group and forming a multi-axis Piezo- NanoPositioning system having a 100 x 100 x 100 μm, XYZ tri-axial positioning and scanning range. This micro-robot 22 can be used to manipulate or move some very small detectors such as, without limitation, an optical fiber or a gripper.

[0038] As shown in Figure 3, the high precision manipulator 10 comprises a test assembly 25 including various sensors and elements displaced and manipulated through both the industrial robot 11 and micro-robot 22. These sensors and elements may comprise, for example and without limitation, a vision system in the infrared (IR) frequency band 26, a vision system in the visible frequency band 27, an optical fiber 28, a load cell (not shown), a photodiode 29, an InGaS large area detector 30, and a pneumatic head (not shown) for picking- up, manipulating and placing small components.

[0039] Figure 4 illustrates the control station 24, for controlling operation of the high precision manipulator 10. In the non-limitative example, the control station 24 comprises, amongst others, a National Instrument*™* analog card, a computer, a Fanuc™ controller, a PI NanoCube™ controller, a wave meter, an optical power meter, an Optical Spectrum Analyser (OSA), etc.

[0040] In the non-limitative example of the bar and/or chip tester, the test assembly 25 and control station 24 comprises the following off-the-shell elements that, those of ordinary skill in the art, will know how to assemble and how to operate:

PI Controller PZT servo controller PI controller LVPZT Amplifier PI NanoCube π ^{I M}vπ: P61135 Vision Camera by Watec. I R Camera by Laser Physics Area detector Heason Robot SN 15099 Heason Technologies controller Mod: 881012 SN: 01 012 013 Computer monitor SN: MH73J1005852 National Instrument Chassis PXI-1000B National instrument Card Analog output Number: 6711 National instrument Card Multifunction Number: 6040E National instrument Card motion controller Number: 7344 National instrument Computer Number 8776. PXIT source measure module Card: PX2000-305 PXIT optical power meter card: PX2000-306. Light wave multimeter HP8153A Optical head interface HP 81533A Keithly 2400 (source meter) Keithly 2510 (Tec Source meter) Keithly 2400 (source meter) Keithly 2400 (source meter) Fanuc Robot LR MATE 100 iB Fanuc System R J3iB MATE Fanuc Handle Keyboard Compact computer board Computer mouse. OSA: Optical spectrum analyzer- Black metallic optical table

[0041] Mechanical characteristics of the high precision manipulator 10

[0042] In order to measure the accuracy of the high precision manipulator 10, various techniques could be used.

[0043] A mechanical Heidenhain probe has been used in order to define the resolution of the linear movement of the high precision manipulator 10. A corresponding control card (not shown) has also been used to obtain the data coming from the mechanical probe. [0044] An interferometer has also been used in order to quantify potential vibrations originating from the industrial robot 11. As the measurement is based on the phase shift reflected from a laser beam, no mechanical perturbation could be attributed to a contact point during the measurement.

[0045] _/ Accuracy

[0046] The following table shows results obtained by using the above mentioned mechanical Heidenhain probe and an interferometer on the industrial robot 11.

[0047] The above results show that the piezoelectric micro-robot 12 can be used within the accuracy of the industrial robot 11.

[0048] A 20 nm resolution for the piezoelectric micro-robot 22 has been measured using an interferometer, whereby a 50 nm resolution can be achieved for the overall high precision manipulator 10.

[0049] Test capabilities and characteristics

[0050] Farfield test

[0051] The high precision manipulator 10 can be used to perform the Farfield test which is a classical test in the optoelectronic industry. The test consists of measuring the power of the light at various angles about the axis of the light or laser beam. [0052] A multimeter and a photodiode (for example photodiode 29 of Figure 3) are used in order to perform the Farfield test. Using the high precision manipulator 10, and more precisely the angular property of the manipulator 10 as well as the large area detector 30 (Figure 3) to detect the optical chip, it is possible to manipulate the photodiode 29 (Figure 3) to measure the power of the light at various angles about the axis of the beam by performing the two rotations required for this Farfield test, that is rotations of the photodiode 29 about, for example, axes X and Y perpendicular to each other and located in a plane generally perpendicular to the axis Z corresponding to the axis of the light or laser beam. A rotation of the photodiode 29 is therefore performed around the two main axis X and Y which are perpendicular to the optical axis Z of the optical chip to test to determine the Farfield distribution of the light transmitted along the optical axis Z (see for example the graph of Figure 5). Time and money are therefore saved when performing the test using the high precision manipulator 10.

[0053] Wavelength test

[0054] In order to measure the wavelength of the light coming out from an optical chip (not shown), the optical fiber 28 of Figure 3, for example a 8-micron optical fiber, needs to be aligned with the light or laser beam coming out from the optical chip.

[0055] Conventionally, an expensive and very accurate robot is used together with complex software in order to perform some search to find the power peak. However such approach takes time and fail in many instances.

[0056] According to the illustrative embodiment of the present invention, the vision system in the IR band 26 (Figure 3), for example an IR camera is operated through the industrial robot 11 and has a field of view large enough to cover all potential areas where the light or laser beam to locate could be. A first scan of the vision system through the industrial robot 11 will determine a rough location of the optical chip, including the light or laser beam.

[0057] The IR camera 26 will detect the light of the beam with an accuracy of 30 microns. With this information and knowing the offset between the position of the fiber 28 and the middle of the camera image, it is just needed to bring the optical fiber 28 automatically to the rough location of the optical chip through the industrial robot 11. However, at this point, the fiber 28 is not yet aligned but the power peak is close.

[0058] In order to complete the alignment, a 100X100 micron scan is performed using the micro-robot 22 in order to localize the power peak.

[0059] Improvements comprise the scanning capability and the use of the IR camera, which reduce by 10 the time required for the alignment. More precisely, instead of requiring the conventional alignment time of 60 to 120 seconds, the alignment can be done within 6 seconds.

[0060] The use of a dedicated IR camera 26 in order to locate the beam from the light source before adjusting the position of the detector, for example the optical fiber 28, presents a great advantage.

[0061] The accuracy of detection within the IR vision system 26 can reach 30 microns.

[0062] Figure 6 shows the detection of the light or laser beam by the IR vision system 26. Figure 7 shows the auto scan concept. During auto scan, an analog signal controls the quartz oscillation of the piezoelectric elements of the micro- robot 22 and the National Instrument*™ card synchronizes the overall movement with the input signal. By having both information like the distance and the signal power synchronized, it is possible to draw in real time the 3D characteristic of the power of the light or laser source signal.

[0063] It will further be appreciated that using the curve of Figure 7, within milliseconds, information such as maximum optical power, power at -3db, etc may be extracted.

[0064] It will be appreciated that the capability to align very quickly an optical fiber with a light or laser source will enable to obtain sufficient power to measure and test the wavelength of the light or laser source. [0065] LVI (Light Voltage intensity) test

[0066] A classical test in the optoelectronic industry is to check the characteristics of a laser chip. More precisely, current must be controlled within the chip to be tested and the measurement is typically performed very quickly.

[0067] Various techniques are used to perform this LVI test. Examples comprise using the PXIT board from PXIT™, using synchronization of two Keithly source meters, and the use of a pulse mode of a current generator.

[0068] It will be appreciated that the use of the high precision manipulator 10 reduces the time required to perform this LVI test. Those of ordinary skill in the art will also appreciate that, at the mechanical level, the merge of the two technologies, the Fanuc™ robot and PI NanoCube™, based on a set of piezoelectric quartz elements, works and improves drastically the resolution of the overall robot 10. The resolution achieved typically reaches 50 nanometers.

[0069] Synchronization of the output signal controlling the piezoelectric quartz elements, for instance a sinusoid, and the input signal coming from the power meter representing in this case the optical power is of great advantage with respect to the conventional systems. In the case where it is possible to generate and to acquire both signals at the same time, a direct link is therefore created between the movement of the manipulator 10 and the impact on the signal received. By having both information, it becomes possible to draw a 3D curve representing the power variation of a light or laser beam for example at a 350 milliseconds refresh rate. It becomes therefore possible to visualize the 3D curve in real time. Such feature is of great advantage during the process development and the assembly of an optical package.

[0070] A raster scan option will enable a very quick scan of an area of 100X100 microns. The Z-axis may be controlled too. Also some scan in different planes within a cube may be performed.

[0071] Alternatively, some spiral or orbit may be performed by applying a sinusoidal signal to the X and Y axes of the piezoelectric quartz elements. A circular oscillation of the quartz can have a frequency much higher than any conventional robot; this property, which can be used to produce circular movement, is due to the fact that the piezoelectric micro-robot 22 has a low mechanical inertia. Such capability is very useful in order to track in real time a beam of light moving in space, because each orbit performed by the fiber 28 will be associated to a signal power; then after each current orbit it is just needed, to determine the location of the subsequent orbit, to define the direction of the gradient of light to which is in fact the direction which has to be followed in order to find the power peak.

[0072] It will further be appreciated that, at the test level, the time required for testing has been drastically reduced. In the case of the LVI curve (Figure 8), 1 to 3 seconds are required depending on the number of points and the configuration selected. In the case of the Farfield test (Figure 5), the time required for the test and the curve construction is about 10 seconds.

[0073] It will further be appreciated that the time for aligning a fiber using the IR camera and the real time scanning system is 3 seconds instead of the conventional 1 to 4 minutes depending on the configuration.

[0074] At the software level, the software used to control the overall station is preferably based on an event-driven concept. This means that an operator is able to interact with the system and to take the control whenever he wants. A complex recovery procedure has further been implemented due to this event driven concept.

[0075] Those of ordinary skill in the art will appreciate that, using the high precision manipulator 10, cost is saved and mechanical capability is increased. More precisely, the traditional approach is to use an expensive XYZ Cartesian robot in order to perform the alignment. As the Cartesian robot needs to be very accurate on a minimum travel of 100 millimeters, users have to invest into an expensive robot when the real useful part is 100 microns on the side. In addition a robot of 100 millimeters travel with a resolution of 50 nanometers is very expensive and 98% of the application requires only to be accurate on one or two millimeters. [0076] Furthermore, those of ordinary skill in the art will appreciate that the high precision manipulator 10 disclosed in the foregoing description enables the use of tests that are traditionally done using different expensive equipments and more than one station.

[0077] Although the present invention has been described in the foregoing description by way of a non-restrictive illustrative embodiment, this embodiment can be modified at will, within the scope of the appended claims, without departing from the scope and nature of the invention.

Claims

WHAT IS CLAIMED IS:

1. A manipulator having a positioning resolution, comprising: a first positioning member having a free end and a lower positioning resolution; and a second positioning member mounted on the free end of the first positioning member and having a higher positioning resolution; whereby, in operation, the first positioning member provides for coarser positional adjustment while the . second positioning member provides for finer positional adjustment so that the second positioning member mounted on the free end of the first positioning member improves the positioning resolution of the manipulator from the lower positioning resolution to the higher positioning resolution.

2. A manipulator as defined in claim 1 , wherein the first positioning member comprises an articulated arm of an industrial robot, the articulated arm having said free end.

3. A manipulator as defined in claim 1 , wherein the second positioning member comprises a micro-robot.

4. A manipulator as defined in claim 3, wherein the micro-robot is a piezoelectric micro-robot.

5. A manipulator as defined in claim 2, wherein the second positioning member comprises a micro-robot.

6. A manipulator as defined in claim 5, wherein the micro-robot is a piezoelectric micro-robot.

7. A manipulator as defined in claim 2, wherein the articulated arm comprises a plurality of pivotally interconnected arm sections.

8. A manipulator as defined in claim 5, wherein the articulated arm of the industrial robot is capable of covering an area of 600x600 mm, and the micro-robot has a 100 x 100 x 100 μm tri-axial positioning and scanning range.

9. A manipulator as defined in claim 2, wherein the second positioning member comprises a micro-robot pivotally mounted on the free end of the articulated arm of the industrial robot.

10. A manipulator as defined in claim 1 , further comprising sensors manipulated through the first and second positioning members.

11. A manipulator as defined in claim 5, further comprising sensors manipulated through the articulated arm of the industrial robot and the micro-robot.

12. A. manipulator as defined in claim 1 , further comprising a control station for controlling operation of the first and second positioning members.

13. A method of improving a positioning resolution of a manipulator with a first positioning member having a free end and a first positioning resolution, comprising mounting on the free end of the first positioning member a second positioning member having a second positioning resolution higher than the first positioning resolution whereby, in operation, the first positioning member provides for coarser positional adjustment while the second positioning member provides for finer positional adjustment so that the second positioning member mounted on the free end of the first positioning member improves the positioning resolution of the manipulator from the first positioning resolution to the second positioning resolution.

14. A method of improving a positioning resolution of a manipulator as recited in claim 13, wherein: the first positioning member comprises an articulated arm of an industrial robot, the articulated arm having said free end; and mounting a second positioning member comprises mounting a micro-robot on the free end of the articulated arm of the industrial robot.

15. A method of improving a positioning resolution of a manipulator as recited in claim 14, wherein mounting a micro-robot comprises pivotally mounting a micro-robot on the free end of the articulated arm of the industrial robot.

16. A method of improving a positioning resolution of a manipulator as recited in claim 14, comprising providing the articulated arm of the industrial robot with a coverage area of 600x600 mm, and providing the micro-robot with a tri-axial positioning and scanning range of 100 x 100 x 100 μm.

17. A method of improving a positioning resolution of a manipulator as recited in claim 13, comprising manipulating at least one sensors through the first and second positioning members.

18. A method for positioning an object by means of the manipulator of claim 1 , comprising: performing a coarser positioning of the object using the first positioning member having a lower positioning resolution; and performing a finer positioning of the object using the second positioning member mounted on the free end of the first positioning member and having a finer positioning resolution.

19. A method for performing a Farfield test on an optical device transmitting light along an optical axis using the manipulator of claim 1 , comprising: mounting a light detector on the second positioning member; controlling the first and second positioning members to cause rotation of the light detector about two axes situated in a plane generally perpendicular to the optical axis; and measuring at different angular positions of the light detector about the two axes a Farfield distribution of the light transmitted along the optical axis by said optical device.

20. A method for performing a Farfield test as defined in claim 16, wherein the two axes perpendicular to the optical axis are also perpendicular to each other.

21. A method for testing light output characteristics of an optical device using a manipulator as defined in claim 1, comprising: providing a vision system; providing an optical detector; performing a first scan by displacing the vision system through the first positioning member to determine a rough location of said optical device; moving the optical detector to the rough location using the first positioning member; and measuring the light output characteristics of the optical device through the optical detector manipulated through the second positioning member.

22. A method for testing light output characteristics of an optical device as defined in claim 21, wherein measuring the light output characteristics comprises moving the optical detector through the second positioning member in order to align the optical detector with the optical device.

23. A method for testing light output characteristics of an optical device as defined in claim 21 , wherein measuring the light output characteristics comprises: operating the second positioning member to repeatedly execute a plurality of orbits of the optical detector.

24. A method for testing light output characteristics of an optical device as defined in claim 23, wherein operating the second positioning member comprises: providing light output characteristics corresponding to a current orbit; and determining the position of a subsequent orbit from the light output characteristics of the current orbit.

25. A method for measuring light output characteristics of an optical device, comprising: mounting an optical detector on a micro-robot; operating the micro-robot to repeatedly execute a plurality of orbits of the optical detector in order to measure light output characteristics of the optical device; wherein operating the micro-robot comprises measuring light output characteristics of a current orbit and determining the position of a subsequent orbit using the light output characteristics of the current orbit.