Typically, an apparatus (handler) for handling and testing electronic circuits includes a loading area, a testing area comprising a tester and a tester manipulator, a sorting area and a discharge area; and a transport system for successively moving the electronic circuits from the loading area to the testing area, and from the testing area to the sorting area and the discharge area. In a handler of this type electronic circuits loaded at the loading area and carried by the transport system to the testing area are successively received by the tester manipulator and displaced to a test position. In the test position a tester is connected to a electronic circuit, and the test is performed. A tested electronic circuit is moved by the transport system to the sorting area in which the tested electronic circuit is sorted according to its test results. The electronic circuits are discharged at the discharge area which can be divided in sections.

Background of the invention There are generally two forms of the above-mentioned handler, a vertical transfer handler wherein electronic circuits to be tested slide under their own weight along vertical or inclined rails, and a horizontal transfer handler wherein electronic circuits are transferred in a horizontal direction by a transport mechanism.

A typical handler of the second form disclosed in US 5,865,319 is intended for testing IC devices. This handler includes a loading area (loader), a testing area including a tester and a tester manipulator (carrier), a sorting area and a discharge area (unloader) ; and a transport system for successively moving the printed circuit boards from the loading area to the testing area, and from the testing area to the discharge area, the transport system being constituted by carriers mounted on

movable arms. Located on a flat horizontal surface, said areas are respectively accessible to said carriers.

In this handler, the handling process includes several pick-and-place operations which are known to be time-taking. Thus, handling of each IC device takes quite a lot of time, and the handler throughput is correspondingly low.

A typical handler of the first form is disclosed in US 5,954,205. This handler is particularly adapted for handling and testing of memory modules typically being referred to as SIMM boards or SIMM's. This handler includes a loading area comprising a magazine assembly, a testing area including a tester with a tester manipulator (transport assembly), a sorting area and a discharge area (bins or containment vessels). A transport system for successively moving the printed circuit boards from the loading area to the testing area, and from the testing area to the discharge area is based on gravity and includes corresponding guideways (rails, chutes, etc.) for guiding memory modules sliding down. It shall be noted that said motion of the memory modules from the loading area to the tester manipulator takes place substantially within a single plane, and said tester manipulator (transport assembly) is adapted to receive a memory module and displace it transversely to this plane to the testing position.

Memory modules to be tested are manually inserted into an inclined sleeve of the magazine assembly to slide down by gravity. A singulator mechanism is used for successively dispensing the circuit boards stored within the sleeve onto the surface on which the tester manipulator (transport assembly) and tester are mounted. Here, the memory modules are successively received and displaced to a test position by the tester manipulator (transport assembly). In the test position a tester is connected to a memory module, and the test is performed. A tested memory module is sorted sliding down a tilt tray to one of two exit chutes and falling to a corresponding one of two bins or containment vessels located at a discharge area.

In this handler, the handling is not as time-taking as in US 5,865,319 because no"pick-and-place"operations are involved here.

However, in US 5,954,205 handler, sorting out into two (good/bad) grades is available. It shall be noted that sorting into more grades is often required.

In many known handlers including US 5,954,205 memory modules in their way through get in hard contact with each other and with some handler structural elements (such as housing top surface or containment vessels). This can damage components of a memory module.

Further, the embodiment of the apparatus presented in Figs. 2 and 3 of US 5,954,205 can hardly be called"operator-friendly". In fact, it seems that, to load or discharge the memory modules, an operator will have to approach the handler from different sides and, probably, extend his hands and bend down.

As is well known, in gravity handlers such as US 5,954,205, a distortion of a memory module or a slight discordance in dimensions between a memory module and a rail may cause jamming. The problem of jamming is much discussed in US 5,954,205 (see columns 2,3, and 4), but not solved completely. Thus, no measures preventing jamming, say, in the magazine assembly are proposed in US 5,954,205.

Summary of the invention The object of the invention is to overcome the drawbacks of both the above- mentioned forms of prior art handlers and provide a high-throughput, reliable and "operator-friendly"handler which allows handling without any jamming or damaging and in which the tested memory modules can be sorted out into an unlimited number of grades.

According to one aspect of the present invention, claimed is a printed circuit board handling and testing apparatus comprising a loading area, a testing area including a tester for supplying test signals to an electronic circuit under test and receiving response signals, and a tester manipulator adapted to successively receive the electronic circuits in the testing area and displace them to the testing position, a sorting area, a discharge area, and a transport system for successively moving the electronic circuits from the loading area to the testing area, and from the testing area to the sorting area and the discharge area, wherein said motion of said electronic circuits from the loading area to the testing area takes place substantially within a single plane, with the electronic circuits oriented transversely to said single plane, and said displacement of electronic circuits to the testing position takes place transversely to said single plane, wherein the transport system includes at least one movable

holder for receiving at least one electronic circuit to be tested, the transport system futher including a transport mechanism for effecting said motion of said at least one electronic circuit received in said holder, said single plane is horizontal, said motion of said electronic circuits from the testing area to the discharge area also takes place substantially within said horizontal plane, and the loading area and the discharge area occupy overlapping sections of said horizontal plane.

Thus, the transport system is based on a transport mechanism rather than gravity. This system eliminates guideways along which electronic circuits slide and, therefore, eliminates jamming.

By properly spacing the holders, any mechanical contact between the electronic circuits is eliminated. Therefore, the electronic circuits are not damaged while handling.

Overlapping loading area and discharge area make the operator's work convenient because he can easily reach both areas to load and discharge electronic circuits. Thus, a constant and convenient operator's workplace can be arranged.

Preferably, the holder is adapted to receive, in side-by-side relation, two or more electronic circuits. In such a holder the memory modules are arranged with a suitable spacing to avoid their contacting and damaging. Further, in this embodiment the transport mechanism is adapted to move the holder stepwise, successively placing each said electronic circuit to a position to be received by the tester manipulator.

Preferably, at least one buffer station is located between the loading area and the tester manipulator, and at least one buffer station is located between the tester manipulator and the discharge area. Thus, movable holders from the loading area come to the testing area through the buffer area, not directly which makes the loading operation relatively independent from the testing operation. The buffer station between the tester manipulator and the discharge area makes the discharge operation relatively independent from the testing operation. Thus, there is no need to synchronize loading/discharging operations with the testing operation, and the handler operation is simplified.

Preferably, said motion of said electronic circuits is effected following a substantially rectangular transport path, said discharge area being arranged within one side of said rectangular transport path.

The tester manipulator is preferably arranged on the opposite side of said rectangular transport path.

Preferably, the sorting area and said discharge area occupy overlapping sections of said horizontal plane.

Said electronic circuit is preferably a memory module.

According to another aspect of the present invention, claimed is a method of handling electronic circuits in a handling and testing apparatus, the method comprising the following steps: a) loading electronic circuits to be tested into a movable holder which holds them in a vertical orientation ; b) horizontally moving the holder with the electronic circuits received therein to the testing area to place one of the electronic circuits in a position to be received by the tester manipulator; c) receiving said one electronic circuit by the tester manipulator, removing it from the movable holder and displacing it downwards to the testing position ; d) testing the electronic circuit; e) transfer of the electronic circuit from the testing position back to the movable holder by the tester manipulator; f) horizontally moving the holder to put the next electronic circuit in a position to be received by the tester manipulator ; g) repeating steps"c"to"f"until the last electronic circuit in the carrier is tested; h) horizontally moving the holder with the tested electronic circuits received therein to the place they were loaded ; i) discharging the tested electronic circuits from the movable holder in a sequence corresponding to their grades determined by the test.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood with reference to the following more detailed description of its preferred embodiment and accompanying drawings in which : Figs. 1 a-1 c are general perspective views of a handler of the present invention wherein the movable holders are in subsequent operating positions; Fig. 2 is a schematic perspective view illustrating the transport system of the handler presented in Fig. 1a ; Fig. 3 is an expanded perspective view showing mechanisms of the transport system of Fig. 2 ; Fig. 4 is an expanded perspective view showing a mechanism for a stepwise movement of the movable holders as seen in Fig. 3; Figs. 5a and 5b are perspective views showing the tester manipulator in a receiving position and a depressed position, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION According to Figs. 1a, 1b and 1c, a handler 100 comprises a top plate 101 on which four identical movable holders 301-304 are placed. Vertically-oriented memory modules 500 are received in the movable holders which, together with a transport mechanism 200 (Fig. 2) further described in more detail, constitute a transport system of the handler. Each movable holder presented in the drawings accomodates 32 memory modules. However, most of the memory modules are not shown in the drawings for clarity. Only several inserted modules 500 are shown in Figs. 1 a, 1 b and 1c. Further, to simplify the drawings, no electronic components are shown on the board (PCB) constituting the base of each electronic component. Thus, these memory modules are presented in the drawings as rectangular plates. It shall be noted that the orientation of a memory module is understood here as the orientation of a plane within which this plate lies.

Each movable holder 301-304 is generally in the form of a frame in which memory modules 500 are held by pairs of opposite holding members 311,312 spaced along the opposite holding bars 313,314 of the frame. A pair of holding

members 311,312 is configured to hold a memory module 500, i. e. to restrict its movement in any direction except the upwards direction. Thus, a memory module 500 can be inserted against stop from above and withdrawn by pulling upwards. However, each pair of holding members 311,312 is adapted to be drawn apart to release the memory module 500 held therebetween. Spaced along the bottom face of each holding bar 313,314 are rectangular recesses 320 (see Fig. 3), the pitch of the recesses being equal to the pitch of the holding members 311,312.

In the central part of one edge of the top plate 101 (see Figs. 1a, 1b, 1c) a control panel 401 is located. It shall be understood that, in operation, an operator seated by the side of the top plate 101 is facing the control panel 401. Next to the control panel, in the forward direction as seen by the operator, is a movable holder station 102 which receives the movable holder 301-304 under loading, sorting or discharging operation. Thus, in the station 102 a loading area, sorting area and discharge area overlap. The control panel 401 and the movable holder station 102 constitute the operator interface area 400. Next to the operator interface area 400, in the forward direction as seen by the operator, is a testing area comprising a tester manipulator 600. Sitting in his workplace, the operator can bserve and control the process of handling, as well as perform loading, sorting and discharging operations.

Thus, the claimed apparatus is in fact operator-friendly.

In Fig. 2 the top plate 101 and most handler parts (including fastening devices) are omitted, thus making visible the transport mechanism 200 disposed under the top plate 101 and adapted to move the movable holders 301-304 (also shown in Fig. 2) from the station 102 to the testing area, and from the testing area to the station 102 (not shown in Fig. 2).

In motion, the movable holders slide on the surface of the top plate 101 driven by driving members of the transport mechanism 200 and guided by guides 103-107 (Fig. 1b). This motion is effected following a rectangular path marked in Fig. 1a by four arrows : F (forward direction), B (backward direction), L (left direction), and R (right direction). It can be seen that these directions are defined as seen by the operator. The same relates to the definitions herein regarding directions such as "front end"or"left side", etc. Besides,"F"or"B"directions can further be referred to

as"longitudinal direction", and"L"and"R"directions can further be referred to as "transversal direction".

Control buttons 402 are disposed to be handy on the control panel 401 of the operator interface area 400. Further, the operator interface area includes 32 indicators 408 and 32 photon-coupled-circuits (PCD) 410 spaced along the"L" direction in two equally spaced parallel rows, each PCD 410 opposing an indicator 408 electrically coupled thereto (Fig. 1a). Each indicator 408 is a dual-colour emitter which can be dark, green and red. Each PCD 410 consists of a light-emitting diode (LED) and a photodiode (PD). The number (32) and spacing of the pairs"indicator- PCD"are the same as the number and spacing of the memory modules 500 in the movable holder 301-304. The PCDs 410 can be displaced between a lowered position in which they allow the passage of the movable holder 301-304, and a raised (operative) position in which each memory module 500 inserted into the movable holder 301-304 resting in the station 102, is between the LED and the PD of a corresponding PCD, thus blocking the light from the LED to the PD. Thus, the memory module presence in or absence from, the movable holder 301-304 can be detected by the PCDs 410 and indicated by the indicators 408.

The transport mechanism 200 is shown in Fig. 2 in which the top plate 101 is not shown, the mechanism comprising a pair of transport devices 210,230 for moving the movable holder 301-304 in the"F"and"B"directions, respectively. These motions are quite similar, and therefore transport devices 210,230 are identical. Further, the transport mechanism 200 comprises a pair of transport devices 250,270 (see Figs. 2, 3,4) for moving the movable holder 301-304 in the"L"and"R"directions, respectively. In Fig. 2, each of two movable holders 302 and 303 is shown with one its angle part omitted, thus making visible the transport device 250 and 270, respectively, positioned right below this angle part.

The transport device 270 for moving the movable holder 301-304 to the right is designed to cooperate with the tester manipulator. Thus, the device 270 is adapted to move the movable holder 301-304 stepwise, successively placing each memory module 500 held therein to a position to be received by the tester manipulator. It can be seen that such a stepwise or indexing motion is unnecessary when moving the

movable holder 301-304 in the left direction. However, in the present embodiment of the invention the transport device 250 is identical with said transport device 270, resulting in a simplier and cheaper construction. The transport devices 250,270 are hereinafter also referred to as"indexers". It shall be understood that another transport device 250 not providing for a stepwise motion may be used for moving the movable holder 301-304 in the left direction.

The indexer 250 will now be described with reference to Figs. 1,3 and 4. It shall be noted that Fig. 3 is viewed from the side opposing the operator's side, therefore the arrow indicating the L-direction shows right, and the arrow indicating the B-direction shows forward in Fig. 3. Omitted for clarity in Fig. 3 are the same elements as in Fig. 2, as well as the most part of the movable holder 301 of which only the holding bar 314 is seen. Further, in Fig. 3 the movable holders 301,302 are in the same position as in Figs. 1a and 2.

As best seen in Fig. 4, the indexer 250 comprises a bracket 256 having two lugs 257,258. Pivotally mounted in the lugs 257,258 is a hollow cylindrical member 251 provided with a tooth 252 projecting backwards and an axially elongated slot 253 facing upwards. Fixed inside the cylindrical member 251 is a pneumatic cylinder 260 having a driving finger 261 projecting upwards through the slot 253 and a corresponding opening 255 (Fig. 1b) in the top panel 101, and adapted, on actuation of the cylinder 260, to shift axially (in the L-direction) within the slot 253 to a distance equal to the pitch of the holding members 311,312. The pneumatic cylinder 260, as well as other pneumatic cylinders described below, is connected via not shown means to an air compressor (not shown) and actuated by feeding compressed air thereto. The cylindrical member 251 is adapted to pivot by means of a pneumatic cylinder 254 to set the tooth 252 in a position in which it projects upwards through the opening 255. The tooth 252 and the driving finger 261 are axially dimensioned so that the tooth 252 and finger 261 can enter the rectangular recesses 320 in the bottom of the movable holder 301-304.

The operation of the indexer 250 will now be described starting from the moment when the movable holders 301 and 302 are in the position shown in Figs. 1a, 2 and 3, i. e. the movable holder 301 is in its rightmost position, and the movable

holder 302, adjacent thereto, is in the station 102. In this position, the indexer 250 is in the above-described state (Fig. 3) wherein the tooth 252 is facing backwards, and the finger 261, located at the right end of the slot 253, is received in the leftmost recess 320 of the movable holder 301. Thus, the indexer 250 is ready to move the movable holder 301 in the L-direction. On actuation of the cylinder 260, the driving finger 261 shifts within the slot 253 in the L-direction, to the left end of the slot 253, thus pushing in the same direction the movable holder 301, with its adjacent movable holder 302, to a distance equal to the pitch of the holding members 311,312. Then, the pneumatic cylinder 254 is actuated, causing the cylindrical member 251 to pivot, so that the finger 261, turning forward, disengages the leftmost recess 320, while the tooth 252 turns up, entering the next recess 320 and thus locking the movable holder 301 in its new position. The cylinder 260 is now disconnected from compressed air, and the driving finger 261, drawn by a spring (not shown), returns back to the right end of the slot 253. Now, the cylinder 254 is disconnected from compressed air, and the cylindrical member 251, under the force of a not-shown spring, turns to its initial position wherein the tooth 252 is facing backwards, and the upwards-projecting finger 261 is received in the recess 320 which is next to the leftmost recess of the movable holder 301. In this position the indexer 250 is ready to move the movable holders 301 and 302 a step further by repeating the above operations. Thus, a step-by-step motion of the movable holders 301 and 302 is achieved, resulting in reaching the position shown in Fig. 1b wherein the movable holder 301 is in the station 102, and the movable holder 302 is set against the guide 104.

As shown in Fig. 1 b, the movable holders 303 and 304 have also been moved by the transport system. This motion was effected by the indexer 270. The operation of the indexer 270 is identical with the operation of the indexer 250 just described. In operation, the indexer 270 successively places each memory module 500 to a position to be received by the tester manipulator 600. The tester manipulator 600 co- operating with the indexer 270 is described below.

In the position shown in Fig. 1b, the movable holder 302 is ready to be transferred in the"F"direction by the transport device 210 best seen in Figs. 2 and 3,

and the movable holder 304 is ready to be transferred in the"F"direction by the transport device 230.

The transport device 210 includes driving pins 218,219 protruding upwards from longitudinal slots 108,109 formed in the top plate 101. The driving pins 218,219 are driven by a pneumatic cylinder 214 via a mechanism further described in detail.

This mechanism is necessary to ensure a precise coordination in the motion of the driving pins 218,219 to avoid any distortion and, as a result, jam of the movable holder 301-304.

A longitudinally extendable rod 215 of the pneumatic cylinder 214 is connected with a movable rack 221 engaged with a rack pinion 222 fitted on a shaft 223 having its ends respectively mounted in the front ends of two fixed side-bars 212,213.

Further, the shaft 223 has two front wheels 224,225 fitted on its ends. The front wheels 224,225 and two rear wheels 226,227 mounted at the rear ends of the side- bars 212,213 are respectively passed over by belts 228,229. The upper parts of the belts 228,229 extend right under the slots 108,109, respectively, the driving pins 218,219 being attached to the belts 228,229 and thus, projecting upwards through the slots 108,109.

The operation of the transport device 210 resulting in the transition of the movable holder 302 from the position shown in Fig. 1b to the position shown in Fig.

1c will now be described. In the position shown in Fig. 1b, the rod 215 of the pneumatic cylinder 214 is extended, the movable holder 302 is in its leftmost position, and the driving pins 218,219 are at the rear ends (located under the guide 103) of the slots 108,109, so that the driving pins 218,219 are set against the rear or outer side of the holding bar 314 and housed in two respective recesses (not seen in the drawings) in the guide 103. When the pneumatic cylinder 214 is activated, the rod 215 starts retracting, driving backwards the movable rack 221 connected thereto. This motion of the rack causes rotation of the rack pinion 222 together with its shaft 223 and front wheels 224,225 and, via the belts 228,229, of the rear wheels 226,227. As a result, the upper parts of the belts 228,229, together with the driving pins 218,219, move forward, the driving pins 218,219 pushing forward the movable holder 302 (guided by guide 104) into the position (presented in Fig. 1c) in which it is adjacent to

the movable holder 303 resting in the testing area. On reaching this position, the driving pins 218,219 are at the front ends of the slots 108,109, and the rod 215 of the pneumatic cylinder 214 is retracted.

Preferably, the transport device 230 is operated simultaneously with the transport device 210, so that the movable holders 302 and 304 are transferred in"F" and"B"directions, respectively, at the same time, reaching the position shown in Fig. 1c. The transport device 230 for moving the movable holder 301-304 in the B- direction acts generally in the same way, but in the reversed sequence, i. e. rod 215, initially retracted, extends to push the movable holder 301-304 backwards. Another distinction in the operation of the transport device 230 is that its driving pins push against the inner side of the holding bar 314, not its outer side.

The tester manipulator 600 will now be described with reference to Figs. 5a, 5b. The manipulator 600 comprises two posts 601,602 mounted on the top plate 102, each post 601,602 comprising a pneumatic cylinder 604 having a retractable rod 605. The posts 601,602 are bridged by a cross-bar 603 having its ends fixed at respective top ends of the retractable rods 605. The cross-bar 603 is arranged transversely to"L"direction, the posts 601,602 being spaced to allow the passage of the movable holder 301-304 therebetween. Mounted on the cross-bar 603 is a clamping device 610 comprsing two clamping arms 606,607 respectively provided with clamping members 611,612 adapted to perform opposing motions to clamp a memory module 500 positioned therebetween. Further, the tester manipulator 600 includes two levers 620 adapted to draw apart the holding members 311,312 to release a memory module 500 held therebetween. The motions of the clamping members 611,612 and levers 620 is effected by means of corresponding pneumatic cylinders. It shall be noted that, to fit memory modules having other dimensions, the clamping device can be adjusted by shifting the clamping arm 607 on the cross-bar 603.

As discussed earlier, the indexer 270 successively places memory modules 500 to a position to be received by the tester manipulator, that is, between the clamping members 611,612. This occurs in the above-described stage where the indexer tooth turns up, entering the rectangular recess in the bottom of the movable

holder and thus locking it in its position. In this stage, the clamping members 611, 612 move towards each other clamping the memory module 500 positioned therebetween. On the contrary, the holding members 311, 312 are drawn apart by the levers 620 to release the memory module 500 as shown in Fig. 4a. Thus, the memory module 500 is received by the tester manipulator. The next stage is actuating the cylinders 604 and thus retracting the rods 605 that will result in depressing the clamping device with the memory module 500. This causes the memory module 500 enter a test socket (not shown) of a tester (not shown) which then conducts a test (or a number of tests) according to a predetermined procedure. Generally, the tester applies test signals of a predetermined pattern to the memory modules under test, receives response signals, attributes each tested memory module, according to its quality determined by the test, to this or that grade and stores this information in memory. Testers having a vertically-oriented socket, e. g. testing stations commercially available from Acuid Corporation may be used with the handler of the present invention. On the end of the test, the rods 605 are extended, and the clamping device is raised. The holding members 311,312 take hold of, and the clamping members 611, 612 release, the memory module 500. Now, the indexer 270 positions the next memory module 500 between the clamping members 611,612, and the above-described operations are repeated.

Generally, the handler operates as follows. The operator inserts memory modules 500 into the movable holder (e. g. 302 as shown in Fig. 1a) resting in the station 102. Each module 500, when inserted, breaks the light from a cooresponding LED to its PD, thus making its corresponding indicator 408 change its colour or switch off. By means of the indexer 250, the loaded movable holder 302 moves to its leftmost position, while the next movable holder 301 takes its place in the station 102.

This leftmost position can be regarded as a buffer station which facilitates in decoupling the motion in"L"direction from the motion in"R"direction and thus, allows the operator in his work to be relatively independent from the tester. Further, the movable holder travels to the testing area and undergos a test as already described, thus moving to the rightmost positioon in its travel in the"R"direction. This rightmost position can be regarded as another buffer station which facilitates in decoupling the

motion in"L"direction from the motion in"R"direction. The movable holder finishes its closed-circuit motion returning back to the operator interface area where the operator can display the test results stored in memory and perform sorting and discharging operations. E. g., the operator wishes to sort out the memory modules to which one specific grade of several grades was assigned. By the operator's command, the information (stored in memory) on the memory modules to which this specific grade was assigned is fed to the control panel, and indicators 408 adjacent these memory modules turn green. The memory modules marked with green lights are easily drawn out by the operator to be placed together. It shall be noted that the number of grades is practically unlimited. This means that even slight variations in quality of the tested memory modules can be distinguished.

The handler according to the preferred embodiment of the present invention is particularly intended for testing memory modules. However, the principles of the invention may be used to design a handler for any other type of electronic circuits by adjusting the dimensions of the movable holders and other handler parts to match the dimensions of the electronic circuits to be processed.

Further, loading and discharging the memory modules can be done by a suitable pick-and place system rather than an operator.

In general, numerous alternative embodiments or variations can be made. The invention shall be limited only by the spirit and scope of the appended claims.