BACKGROUND [0002] Before an electronic device is delivered for sale the testing thereof is very important. The idea of testing is to ensure that an electronic de- vice, such as a mobile phone is in perfect working order and structurally fault- less. During testing, the electronic device under test is transferred into a test chamber through a door opening and is connected to a fixture thereof that holds the electronic device under test in position and operates as a user inter- face for the electronic device. The electronic device is controlled through the fixture and measurement signals are transferred from the electronic device to signal processing equipment.

[0003] The fixture may comprise sensors or actuators or the like that allow carrying out various tests. At the end of a test sequence the elec- tronic device, which has undergone testing, is transferred from the test cham- ber through the door opening and a new electronic device under test is admit- ted to the test chamber.

[0004] While testing is carried out the aim is to minimize external in- terference. The test chamber must therefore be a closed space that does not allow any external interference to enter and/or does not allow signals gener- ated during testing to exit the test chamber to interfere with other devices or tests.

[0005] Interference has been reduced by means of transfer open- ings in the test chamber, which can be opened and closed and through which electronic devices are fed into the test chamber or removed therefrom. It is common to employ a closing part provided with a slide that can be pulled out- wards in order to feed an electronic device from the transfer opening to the test chamber or to remove said device from the test chamber. Such a solution re- quires space to open a transfer opening. In addition, closing such an opening tightly so that no interference is allowed to exit or enter the closed opening to interfere with the testing nevertheless seems difficult or even impossible to im- plement in this way. A hinged door has also been used to close such an open- ing, but in this case too, opening the door requires space and preventing inter- ference from passing through the chink of a closed door is a difficult or impos- sible task.

BRIEF DESCRIPTION [0006] It is an object of the invention to provide an improved method and an arrangement implementing the method.

[0007] This object is achieved with a door arrangement of a test chamber for moving electronic devices under test to and from the test cham- ber, the test chamber comprising at least one door opening, at least one frame providing a frame for each door opening, at least one door, and at least one actuator arrangement for opening and closing the door. Furthermore, each ac- tuator arrangement comprises an opening and closing mechanism and a trans- fer mechanism for each door, whereof the opening and closing mechanism is arranged to move the door in a direction of the normal defining the surface of the door opening in front of the door opening in such a manner that the door is closed by pressing the door against the frame or opened by lifting off the door off the frame, and the transfer mechanism is arranged to transfer the open door in a perpendicular direction in relation to the direction of the normal defin- ing the surface of the door opening close to the door opening for closing, and the transfer mechanism is arranged to transfer the open door in the perpen- dicular direction in relation to the direction of the normal defining the surface of the door opening away from the door opening for transferring electronic de- vices to or from the test chamber.

[0008] The invention also relates to a method for opening and clos- ing a test chamber door for transferring electronic devices under test to and from the test chamber, in which method at least one door is opened and closed using at least one actuator arrangement. Furthermore, the method comprises moving each door using an opening and closing mechanism belonging to the actuator arrangement in a direction of the normal defining the surface of a door opening in front of the door opening in such a manner that the door is closed by pressing the door against the frame or opened by lifting the door off the frame, and transferring the open door using the transfer mechanism belonging to the actuator arrangement in a perpendicular direction in relation to the direc- tion of the normal defining the surface of the door opening close to the door opening for closing, and transferring the open door using the transfer mecha- nism belonging to the actuator arrangement in the perpendicular direction in relation to the direction of the normal defining the surface of the door opening away from the door opening for transferring electronic devices to or from the test chamber.

[0009] The preferred embodiments of the invention are disclosed in the dependent claims.

[0010] The method and arrangement of the invention provide sev- eral advantages. The door can be closed tightly in order to avoid interference from entering or exiting the test chamber or to reduce interference to a level that does not interfere with the testing. In addition, opening the door does not require a lot of space.

LIST OF DRAWINGS [0011] In the following the invention will be described in greater de- tail by means of the preferred embodiments with reference to the accompany- ing drawings, in which Figure 1 shows the structure of a test apparatus, Figure 2 shows a door arrangement on the wall of a test chamber, Figure 3 shows the control of a door arrangement, and Figure 4 is a flow chart showing the method.

DESCRIPTION OF THE EMBODIMENTS [0012] An arrangement according to the invention associated with closing and opening a test chamber is applicable to be used particularly with electronic devices, such as radio frequency testing of mobile phones, however, without being restricted thereto.

[0013] Let us first take a closer look at the structure of the test ap- paratus used in the testing shown in Figure 1. The test system comprises at least one item of measuring equipment 100 for testing electronic devices. The measuring equipment 100 may be placed in a test framework 102, for instance a 19"rack casing, in which the marking"refers to inches corresponding to 25,4 mm.

[0014] The test framework 102 may comprise for instance two test units 104-106, test apparatuses 108-110, a test controller 112, a monitor 114 and a conveyor 116. The test unit may comprise measuring equipment, a test unit controller, a control bus, a power source etc. (not shown in Figure 1). The measuring equipment measure the electronic device under test controlled by the test controller 112 and the unit controller. The unit controller provided with a microprocessor and appropriate programs may also be used for pre- processing signals, for instance filtering and signal processing. However, a unit controller is not necessarily required. A test controller 112 may function as the control means of each test unit through the control bus. Both the electronic parts of the test unit and the electronic device under test may receive the elec- tric power employed from the power source of the test unit.

[0015] The structure of the test apparatus may comprise cabling (not shown in Figure 1), by which the electronic device under test (DUT) and the test electronics of the test unit are connected to one another through a fix- ture and a test handler connector interface belonging thereto. Data transmis- sion of the test handler and the test system control is carried out through the cabling.

[0016] The mechanical parts of the fixture enable to fasten the elec- tronic device under test firmly to the testing and to establish the required elec- trical, mechanical and optical connections well enough. The fixture may include sensors, contact surfaces, optical and acoustic components or actuators that allow performing mechanical tests.

[0017] The electronic device under test can be placed in either of the test units 104-106, in which different test apparatuses 108-110 of the measuring equipment, such as sensors and possibly mechanical testers, are used to measure and test the operation of an electronic device. Testing is con- trolled by a test controller 112, which may also store the test results. A per- sonal computer or the like controlling and carrying out corresponding digital signal processing may function as the controller 112. Test results and other information associated with the testing and serving the user can be shown on the monitor 114. The devices under test can be transferred through a test ap- paratus structure 100 from the testing or to the following test apparatus struc- ture using door openings 116 and conveyors 118 placed in the test apparatus structure 100. The electronic devices under test are fed into the test units 104- 106 of the test apparatus structure 100 through door openings 120-122 in the test apparatus structure. The electronic devices under test can also be put out from the test apparatus structure 100 through the same door openings 120- 122, but generally the test apparatus structure 100 is on opposite sides thereof also provided with door openings for outputting the electronic devices. In gen- eral, the aim is to make the test unit, which may also be referred to as the test chamber, a completely closed space for the duration of the test in order to re- duce interference. Especially when radio frequencies are tested the walls and doors of the test unit should prevent the radio frequency radiation from exiting the test unit and from entering the test unit. The walls and doors of the test unit may be made of a material that conducts electricity, such as metal, or of an adequately small-sized wire mesh. Isolation is also required in optical and acoustic testing.

[0018] In the prior art the door openings 120-122 can be closed for instance using a closing part 132 that is fastened to a slide 134. An actuator arrangement (not shown in Figure 1) may by means of the slide 134 move the closing part 132 back and forth as shown by the arrow. The closing part 132 can thus be pressed against the door opening 120-122 or the closing part 132 can be pulled backwards in order to transfer the electronic devices to or from the test chamber 104-106.

[0019] Figure 2 allows us to study the presented solution, in which the test chamber 104-106 comprises a door opening 200 that corresponds to the door openings 120-122 shown in Figure 1. In general, the walls or panels 250 of the test chamber 104-106 may be provided with more than one door opening 200. The frame 202 that provides a frame for each door opening 200, may comprise seals 2020 and possibly also a step-shaped structure 2022 in order to improve sealing and isolation. Thus, the door 204 may also include a similar step-shaped structure. In order to close each door 200 the door ar- rangement is also provided with one additional door 204. To open and close each door 204 the door arrangement comprises at least one actuator ar- rangement 190, each one of which including for each door an opening and closing mechanism 206 as well as a transfer mechanism 208.

[0020] The opening and closing mechanism 206 is arranged to move the door 204 in a direction of the normal 210 defining the surface of the door opening 200 in front of the door opening 200 in such a manner that the door 204 is closed by pressing the door against the frame 202 or opened by lifting the door 204 off the frame 202. The opening and closing mechanism 206 may comprise a pneumatic or hydraulic compression cylinder 220 that pushes the door 204 into a closed position against the frame 202 or lifts the door 204 off the frame 202. An electric motor can also be used to move the door 204 instead of the compression cylinder 220.

[0021] The transfer mechanism 208 is arranged to transfer the open door 204 in a perpendicular direction 212 in relation to the direction of the normal 210 defining the surface of the door opening 200 close to the door opening 200 for closing. Alternatively the transfer mechanism 208 is arranged to transfer the open door 204 in the perpendicular direction 212 in relation to the direction of the normal 210 defining the surface of the door opening 200 away from the door opening 200 in order to transfer electronic devices to or from the test chamber. The transfer mechanism 206 may comprise a pneu- matic or hydraulic compression cylinder 222 that transfers the door 204. The compression cylinder 222 may be a bellow cylinder. An electric motor can also be used to transfer the door 204 instead of the bellow cylinder 222.

[0022] The actuator arrangement 190 may comprise a controller structure 2060 that controls the door 204 to move straight and evenly in the direction of the normal defining the surface of the door opening. The controller structure 2060 may comprise a pin-like projecting part 2062 fastened to the door 204 and a hole 2064 as a counterpart for the projecting part 2062, into which the projecting part 2062 fits perfectly. The hole 2064 may be located in the transfer mechanism 208, which allows transferring the door 204 in the per- pendicular direction in relation to the direction of the normal defining the sur- face of the door opening. When the door 204 is moved in the direction 210 of the normal defining the surface of the door opening 200, the projecting part 2062 moves in the hole 2064, but the projecting part 2062 prevents the door 204 from moving sideways. When the transfer mechanism 208 transfers the door 204 away from the door opening 200, the hole 2064 in the transfer mechanism 208 pulls the door 204 with it by means of the projecting part 2062.

Other control structures may also be used for moving the door instead of the pin and the hole.

[0023] The transfer mechanism 208 may comprise a sliding struc- ture 2080, which controls the door 204 to move straight and evenly in the per- pendicular direction in relation to the direction of the normal defining the sur- face of the door opening. Each sliding structure 2080 may comprise at least one sliding base 2082 and a sliding part 2084, whereof the sliding base 2082 is fastened to a wall 250 of the test chamber and the sliding part 2084 belongs to the door 204. As shown in Figure 2 the sliding bases 2082 may be located at different ends of the door opening 200, whereby the door 204 moves along the sliding bases 2082 vertically (or horizontally or sideways in general) sup- ported on the sliding parts 2084 in front of the door opening 200. The sliding base 2082 may be provided with a groove shaped as desired, into which the sliding part 2084 of the door 204 is arranged. Then, the door 204 may slide with the sliding part 2084 thereof in the groove of the sliding base 2082 in the direction of one dimension.

[0024] Let us now take a closer look at the door arrangement shown in Figure 3. The door arrangement may comprise a controller 300 for control- ling the opening and closing mechanism 206 as well as the transfer mecha- nism 208 in accordance with the test operations. The controller 300 may be the same as the controller 112 or a part of the controller 112 shown in Figure 1.

When the electronic device under test is to be placed into an empty test cham- ber, the controller 300 signals a request to the opening and closing mechanism 206 to lift the door 204 off the frame 202. The controller 300 also signals a re- quest to the transfer mechanism 208 to transfer the door 204 placed in front of the door opening 200. When no obstacles are placed in front of the door 200, the electronic device under test can be placed into the test chamber. Before starting the test, the controller 300 signals a request to the transfer mechanism 208 to transfer the door 204back in front of the door opening 200. When the door 204 is placed in front of the door opening 200 the controller signals a re- quest to the opening and closing mechanism 206 to press the door 204 against the frame 202 of the door opening 200. At the end of the test the door 204 is opened controlled by the controller 300 as shown above and the device under test is removed from the test chamber. When a new electronic device under test is placed into the test chamber the door 204 is closed controlled by the controller as shown above.

[0025] A flow chart of the method is shown in Figure 4. In order to open and close each door each actuator arrangement is provided with an opening and closing mechanism as well as a transfer mechanism for each door. In step 400, each door is moved using the opening and closing mecha- nism belonging to the actuator arrangement in the direction of the normal de- fining the surface of the door opening in front of the door opening in such a manner that the door is closed by pressing the door against the frame or opened by lifting the door off the frame. In step 402, the open door is trans- ferred using the transfer mechanism in the perpendicular direction in relation to the direction of the normal defining the surface of the door opening close to the door opening for closing. In step 404, the open door is transferred using the transfer mechanism in the perpendicular direction in relation to the direction of the normal defining the surface of the door opening away from the door open- ing in order to transfer the electronic devices to or from the test chamber.

[0026] Even though the invention has above been described with reference to the examples shown in the drawings, it is apparent that the inven- tion is not restricted thereto but can be amended in various ways within the scope of the accompanying claims.