Test carrier capable of reducing test error and test method of circuit board assembly

Abstract

The invention discloses a test carrier capable of reducing test errors and a test method of a circuit board assembly. The test carrier is used for bearing a circuit board assembly. The circuit board assembly comprises a circuit board and a heat source arranged on one side of the circuit board. The test carrier comprises a housing and at least one heat conduction member. The shell is provided with a containing space used for containing at least part of the circuit board. The at least one heat conducting member is disposed and thermally coupled to the housing, and is at least partially located in the accommodating space. The at least one heat conducting member is used for contacting the circuit board and thermally coupled to the heat source. The test method of the circuit board assembly comprises the following steps: selectively switching the on-off state of at least one channel of at least one heat source of each circuit board assembly in a to-be-tested state according to the temperature value of each circuit board assembly;

Description

Technical Field

[0001] The present invention relates to a test vehicle and a test method for a circuit board assembly, and in particular to a test vehicle and a test method for a circuit board assembly capable of reducing test errors. Background Art

[0002] Optical modules can transmit and / or receive optical signals for applications such as, but not limited to, data centers, cable TV, and fiber-to-the-home (FTTH). Using optical modules for transmission can provide higher transmission rates and signal bandwidth over longer distances. To promote global compatibility of optical internet products and reduce maintenance burdens, organizations such as the Multi-Source Agreement (MSA), the Institute of Electrical and Electronics Engineers (IEEE), and the Optical Internetworking Forum (OIF) have developed several form factors suitable for different signal transmission rates. These form factors include, but are not limited to, XFP, SFP, QSFP (Quad Small Form Factor Pluggable), QSFP-DD (Double Density), OSFP (Octal Small Form Factor Pluggable), and CPO (Co-Packaged Optics).

[0003] Existing optical modules face challenges such as optical efficiency (power), space management, thermal management, insertion loss, and manufacturing yield. Summary of the Invention

[0004] The present invention provides a testing vehicle and a testing method for a circuit board assembly to solve the problems of existing optical modules.

[0005] A test carrier disclosed in one embodiment of the present invention is used to support a circuit board assembly. The circuit board assembly includes a circuit board and a heat source disposed on one side of the circuit board. The test carrier includes a housing and at least one thermally conductive member. The housing has a storage space for accommodating at least a portion of the circuit board. The at least one thermally conductive member is disposed and thermally coupled to the housing and is at least partially located in the storage space. The at least one thermally conductive member is configured to contact the circuit board and thermally couple to the heat source.

[0006] Another embodiment of the present invention discloses a circuit board assembly testing method comprising: placing a plurality of circuit board assemblies in an oven and placing the circuit board assemblies in a test state; obtaining a temperature value of each circuit board assembly in the test state through a temperature sensor of each circuit board assembly; and selectively switching the on / off state of at least one channel of at least one heat source of each circuit board assembly in the test state based on the temperature value of each circuit board assembly.

[0007] According to the test vehicle and the test method of the circuit board assembly disclosed in the above embodiment, in the test vehicle, the heat conductor can be used to contact the circuit board and be thermally coupled to the heat source. Therefore, the heat conductor can transfer the heat generated by the heat source to the housing, so that the temperature on the circuit board is more uniform. In this way, the temperature error between the circuit board and the heat source can be reduced, and heat sources with early failure or defective performance can be accurately screened out. Alternatively, in the test method of the circuit board assembly, the switch state of the channel of the heat source of the circuit board assembly in the test state can be selectively switched according to the temperature value of each circuit board assembly. The temperature of the circuit board assembly can be correspondingly increased or decreased by opening or closing the channel. Therefore, the above-mentioned method of switching the switch state according to the temperature value can reduce the temperature error between the circuit board and the heat source, and can accurately screen out heat sources with early failure or defective performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 FIG. 4 is a perspective view of a test vehicle and a circuit board assembly according to an embodiment of the present invention.

[0009] Figure 2 for Figure 1 Exploded view of the test vehicle and circuit board assembly.

[0010] Figure 3 for Figure 1 Top view of the test vehicle and circuit board assembly in Figure 1.

[0011] Figure 4 For testing carriers and circuit board components along Figure 3 The cross-sectional diagram is shown by the cutting line 4-4.

[0012] Figure 5 For testing carriers and circuit board components along Figure 3 The cross-sectional diagram is shown by the cutting line 5-5 in FIG.

[0013] Figure 6 FIG. 1 is a schematic diagram illustrating a method for testing a circuit board assembly according to an embodiment of the present invention.

[0014] Figure 7 FIG. 4 is a flow chart of a method for testing a circuit board assembly according to an embodiment of the present invention.

[0015] [Description of Reference Numerals]

[0016] 10: Test Vehicle

[0017] 100: Shell

[0018] 110: Base

[0019] 111: Baseboard

[0020] 112: Side panels

[0021] 1120: Limiting groove

[0022] 1121: Positioning convex part

[0023] 115: First positioning structure

[0024] 116: Elastic Arm

[0025] 117: Card bump

[0026] 118: Fixed end

[0027] 119: Active end

[0028] 120: Press cover

[0029] 125: Second positioning structure

[0030] 130: Pressure component

[0031] 131: Pressure plate

[0032] 132: Elastic element

[0033] 133: Limit column

[0034] 134: Fixed end

[0035] 135: Limit end

[0036] 150: Accommodation space

[0037] 200: Thermal Conductor

[0038] 20: Circuit board assembly

[0039] 21: Circuit Board

[0040] 22,23: Heat source

[0041] 24: Temperature sensor

[0042] 28: Positioning groove

[0043] 30: Object under test

[0044] 40: Oven

[0045] 41: Shelves

[0046] S01~S06:Steps DETAILED DESCRIPTION

[0047] The following detailed description of the features and advantages of the embodiments of the present invention is sufficient to enable those skilled in the art to understand the technical content of the embodiments of the present invention and implement them accordingly. Furthermore, based on the disclosure, scope of protection, and accompanying drawings of this specification, those skilled in the art can easily understand the relevant objectives and advantages of the present invention. The following embodiments further illustrate the concepts of the present invention and are not intended to limit the scope of the present invention in any way.

[0048] Generally speaking, lasers packaged using chip-on-board (COB) packaging, such as vertical-cavity surface-emitting lasers (VCSELs), directly modulated lasers (DMLs), and electro-optically modulated lasers (EMLs), are more complex to manufacture. Consequently, these lasers are prone to reliability issues and shorter lifespans.

[0049] To ensure the reliability and lifespan of lasers, they must undergo a burn-in test before leaving the factory. During the burn-in test, the circuit board equipped with the laser is placed in an oven and a high current is applied. However, this burn-in test has a large temperature error and cannot accurately screen out lasers that fail early or have performance defects. Furthermore, due to process limitations, it is difficult to directly measure the actual temperature of the laser during the burn-in test. Therefore, the laser temperature is usually monitored indirectly through a temperature sensor in the circuit board assembly. However, there is often a temperature error between the temperature value measured by the temperature sensor and the actual temperature of the laser. This temperature error makes it difficult for the burn-in test to accurately screen out lasers that fail early or have performance defects. Specifically, this temperature error is usually greater than 5 degrees Celsius.

[0050] According to one embodiment of the present invention, in a test vehicle, a thermal conductor can be used to contact a circuit board and thermally couple to a heat source. Therefore, the thermal conductor can transfer heat generated by the heat source to the housing, making the temperature of the circuit board assembly more uniform. In this way, the temperature error between the circuit board assembly and the heat source can be reduced, and heat sources with early failure or performance defects can be accurately screened out. According to actual tests, using the test vehicle of the above embodiment, the temperature error between the temperature measured by the temperature sensor of the circuit board assembly and the actual temperature of a heat source such as a laser can be reduced to within 1.5 degrees Celsius.

[0051] According to one embodiment of the present invention, in a circuit board assembly testing method, the on / off state of a heat source channel of a circuit board assembly under test can be selectively switched based on the temperature value of each circuit board assembly. The opening or closing of the channel can cause the temperature of the circuit board assembly to rise or fall accordingly. Therefore, this method of switching the on / off state based on the temperature value can reduce the temperature error between the circuit board and the heat source, allowing for the precise screening of lasers with premature failure or performance defects. According to actual tests, using the test vehicle of the above embodiment, the temperature error between the temperature measured by the temperature sensor of the circuit board assembly and the actual temperature can be reduced to within 0.5 degrees Celsius.

[0052] According to a test vehicle or a test method disclosed in an embodiment of the present invention, the temperature difference between these heat sources can be reduced to within 0.5 degrees Celsius, thereby further reducing the temperature error between the circuit board and the heat source.

[0053] Part or all of the technical features disclosed in one or more embodiments of the present invention may be configured in combination to achieve corresponding effects.

[0054] The term "coupled" or "coupled" refers to any connection, linking or similar relationship. Unless otherwise specified, objects that are "coupled" or "coupled" to each other do not need to be directly connected to each other and may be separated by intermediate objects.

[0055] See also Figure 1 and Figure 2 . Figure 1 FIG. 4 is a perspective view of a test vehicle and a circuit board assembly according to an embodiment of the present invention. Figure 2 for Figure 1 Exploded view of the test vehicle and circuit board assembly.

[0056] The test vehicle 10 can be used to carry a circuit board assembly 20. The circuit board assembly 20 may include a circuit board 21 and multiple heat sources 22 and 23 disposed on one side of the circuit board 21, as well as a temperature sensor 24. The heat source 22 may be a laser, such as a vertical cavity surface emitting laser (VCSEL), a directly modulated laser (DML), or an electro-optically modulated laser (EML). The heat source 23 may be a transimpedance amplifier (TIA). The temperature sensor 24 may be a thermistor and may monitor the temperature of the circuit board assembly 20 using a DDMI (Digital Direct Motion Interference Measurement) method.

[0057] See also Figures 2 to 5 . Figure 3 for Figure 1 Top view of the test vehicle and circuit board assembly in Figure 1. Figure 4 For testing carriers and circuit board components along Figure 3 The cross-sectional diagram is shown by the cutting line 4-4. Figure 5For testing carriers and circuit board components along Figure 3 The cross-sectional diagram is shown by the cutting line 5-5 in FIG.

[0058] The test vehicle 10 may include a housing 100 and two heat conducting members 200. The housing 100 may include a base 110, a pressing cover 120, and two pressing assemblies 130. The base 110 may include a bottom plate 111 and two side plates 112. The two side plates 112 may stand on opposite sides of the bottom plate 111.

[0059] Furthermore, in this embodiment, each of the two side plates 112 may have a retaining groove 1120 for retaining the circuit board 21. Furthermore, in this embodiment, each of the two side plates 112 may be provided with a positioning protrusion 1121. The two positioning protrusions 1121 may be respectively positioned in the two positioning grooves 28 of the circuit board 21. The design of the retaining grooves 1120 and the positioning protrusions 1121 further ensures that the circuit board 21 is fixed in place on the test vehicle 10. In other embodiments, the retaining grooves 1120 and the positioning protrusions 1121 may be omitted.

[0060] The pressing cover 120 can be movably mounted on the two side panels 112. When the pressing cover 120 is attached to the base 110, the pressing cover 120 can abut against the two side panels 112. The pressing cover 120, the bottom panel 111, and the two side panels 112 can collectively form a receiving space 150. The receiving space 150 can accommodate at least a portion of the circuit board 21.

[0061] The pressing assembly 130 can be located in the accommodating space 150, and the pressing cover 120 can be used to press the circuit board 21 through the pressing assembly 130. The pressing assembly 130 can include a pressing plate 131, two elastic elements 132 and two limiting columns 133. The pressing plate 131 can be movably disposed on the pressing cover 120 through the two elastic elements 132. The pressing plate 131 can be, for example, approximately in the shape of a letter "ㄇ" and can be used to press the circuit board 21. The two elastic elements 132 can be respectively mounted on the two limiting columns 133. The limiting column 133 can include a fixed end 134 and a limiting end 135 opposite to each other. The fixed end 134 can be fixed to the pressing cover 120. A portion of the pressing plate 131 can be located between the limiting end 135 and the pressing cover 120 and limited by the limiting end 135.

[0062] The two heat conducting members 200 can be separated from each other and can be springs. The heat conducting member 200 can be arranged and thermally coupled to the housing 100. In detail, the heat conducting member 200 can protrude from the bottom plate 111 and can be at least partially located in the accommodating space 150. In this embodiment, the heat conducting member 200 and the base 110 can be integrally formed. The heat conducting member 200 can be used to contact the side of the circuit board 20 away from the heat sources 22 and 23 and can be thermally coupled to the heat sources 22 and 23. In other embodiments, the heat conducting member can also contact the side of the circuit board where the heat source is arranged.

[0063] In addition, the thermal conductivity of the base 110 and the thermal conductive member 200 may be greater than that of the pressing cover 120 . Therefore, the heat generated by the heat sources 22 and 23 can be more effectively transferred to the base 110 and the thermal conductive member 200 .

[0064] Furthermore, when the pressing cover 120 is placed on the base 110, it can be used to press the circuit board 21 to ensure contact between the thermal conductive element 200 and the circuit board 21. The design of the pressing assembly 130 allows the thermal conductive element 200 to be in closer contact with the circuit board 21, allowing the heat generated by the heat sources 22 and 23 to be more effectively transferred to the thermal conductive element 200.

[0065] In this embodiment, the base 110 may have two first positioning structures 115, and the pressing cover 120 may have two second positioning structures 125. The first positioning structure 115 may include an elastic arm 116 and a locking protrusion 117. The elastic arm 116 may include a fixed end 118 and a movable end 119 opposite to each other. The fixed end 118 may be fixed to the base 110. For example, the fixed end 118 may stand on the bottom plate 111. The locking protrusion 117 may protrude from the movable end 119. The second positioning structure 125 may be a locking hole. When the pressing cover 120 is covered on the base 110, the two locking protrusions 117 can be used to respectively lock with the two second positioning structures 125, thereby preventing the pressing cover 120 from opening relative to the base 110.

[0066] The thermal conductor 200 contacts the circuit board 21 and is thermally coupled to the heat sources 22 and 23. Therefore, the thermal conductor 200 transfers the heat generated by the heat sources 22 and 23 to the housing 100, thereby achieving a more uniform temperature across the circuit board 21. This reduces the error between the temperature measured by the temperature sensor 24 on the circuit board 21 and the actual temperature of the heat source 22, allowing for the precise screening of heat sources 22 with premature failure or performance defects.

[0067] In addition, the base 110 can fix the circuit board assembly 20 at a desired position, so that the circuit board assembly 20 can be connected to an external electrical connector (not shown).

[0068] In addition, since the heat conducting member 200 and the first positioning structure 115 are both in the form of springs, they have the advantage of being structurally stable and reliable, and can be repeatedly used without failure.

[0069] Furthermore, the spring-shaped thermal conductive element 200 can better fit the circuit board 21, thereby increasing the efficiency of transferring heat generated by the heat sources 22 and 23 to the thermal conductive element 200. In this embodiment or other embodiments, a thermal conductive medium, such as a thermally conductive pad, can be added between the thermal conductive element 200 and the circuit board 21 to further increase the efficiency of transferring heat generated by the heat sources 22 and 23 to the thermal conductive element 200.

[0070] Next, please refer to Figure 2 , Figure 6 and Figure 7 , Figure 6 FIG. 1 is a schematic diagram illustrating a method for testing a circuit board assembly according to an embodiment of the present invention. Figure 7 FIG. 4 is a flow chart of a method for testing a circuit board assembly according to an embodiment of the present invention. Figure 1 The testing method of the circuit board assembly 20 may be a burn-in test, and may include the following steps.

[0071] First, step S01 is performed to place a plurality of circuit board assemblies 20 in an oven 40 and place the circuit board assemblies 20 in a state to be tested. In this embodiment, a plurality of objects to be tested 30 including a test carrier 10 and circuit board assemblies 20 can be placed on a plurality of shelves 41 of the oven 40. More specifically, in this embodiment, the circuit board assemblies 20 can be placed in the test carrier 10 to form the objects to be tested 30, and then the objects to be tested 30 can be placed on the shelves 41 of the oven 40. Figure 6 In order to simplify the drawings, the appearance of the DUT 30 including the test carrier 10 and the PCB assembly 20 is simplified. In this embodiment, the heat source 23 of each PCB assembly 20 may have multiple channels. When the PCB assembly 20 is under test, some of the channels in the heat source 23 of each PCB assembly 20 may be set to an open state, while the remaining channels may be set to a closed state.

[0072] Next, step S02 is performed, where the temperature sensor 24 of the circuit board assembly 20 obtains an average temperature value of the circuit board assemblies 20 in the test state. It should be noted that after step S01, a period of time (e.g., 20 minutes) may be waited before step S02 to ensure that the oven 40 has fully heated the circuit board assemblies 20.

[0073] Next, step S03 may be performed to adjust the temperature of oven 40 based on the average temperature value. Specifically, the average temperature value may be compared with a reference temperature value, and a determination may be made as to whether the difference between the average temperature value and the reference temperature value is within an error range. If the difference between the average temperature value and the reference temperature value is within the error range, step S04 may be performed to obtain a temperature value of each circuit board assembly 20 in the test state via the temperature sensor 24 of each circuit board assembly 20. If the difference between the average temperature value and the reference temperature value is outside the error range, step S05 may be performed to adjust the temperature of oven 40 based on the difference between the average temperature value and the reference temperature value, and step S02 may be performed again. It should be noted that after performing step S05, a period of time (e.g., 20 minutes) may be waited before performing step S02 again to ensure that oven 40 has sufficiently heated circuit board assemblies 20.

[0074] Steps S03 and S05 ensure that the oven 40 controls the temperature of the circuit board assembly 20 to be within a range close to the reference temperature. However, in other embodiments, if the difference between the temperature of the oven and the temperature of the circuit board assembly is small, steps S03 and S05 may be omitted.

[0075] After step S04, step S06 can proceed to selectively switch the on / off state of the channels of the heat source 23 of each circuit board assembly 20 under test based on the temperature value of each circuit board assembly 20. Specifically, the temperature value of each circuit board assembly 20 is compared with at least one critical temperature value, and based on the comparison result, at least one of the channels set to an open state can be closed or at least one of the channels set to a closed state can be opened. The opening or closing of the channels can cause the temperature of the circuit board assembly to rise or fall accordingly. Therefore, this method of switching the on / off state based on the temperature value can reduce the error between the temperature measured by the temperature sensor 24 on the circuit board 21 and the actual temperature of the heat source 22, thereby accurately screening out heat sources 22 with premature failure or performance defects. Because different channels in the heat source 23 of the same circuit board assembly 20 can have different heat outputs, different channels can be compared with different critical temperature values ​​to more accurately control the temperature of the circuit board assembly 20 through switching.

[0076] In this embodiment, since the on / off state of the channel of the heat source 23 serving as a transimpedance amplifier is switched, the heat source 22 serving as a laser can be accurately tested without affecting the operation of the heat source 22 serving as a laser.

[0077] Furthermore, steps S04 and S05 may be repeated until the temperature value of each circuit board assembly 20 in the test state has been adjusted to be within a desired error range according to whether the channel is opened or closed.

[0078] It should be noted that, in other embodiments, the temperature of a single circuit board assembly may be adjusted by switching a single channel of a single heat source of a single circuit board assembly on and off.

Claims

1. A test vehicle, characterized in that: The test vehicle is used to carry a circuit board assembly, the circuit board assembly including a circuit board and a heat source disposed on one side of the circuit board. The test vehicle includes: a housing having a receiving space for receiving at least a portion of the circuit board; and At least one heat conducting member, disposed and thermally coupled to the housing and at least partially located in the accommodating space; The at least one heat conducting element is used to contact the circuit board and be thermally coupled to the heat source.

2. The test carrier according to claim 1, wherein: The at least one heat conducting member is used for contacting a side of the circuit board away from the heat source.

3. The test carrier according to claim 1, wherein: The at least one heat conducting component is a spring.

4. The test carrier according to claim 1, wherein: The shell includes a base and a pressing cover. The pressing cover is movably arranged on the base and forms the accommodating space together with the base. The at least one heat conductive member protrudes from the base. When the pressing cover is covered on the base, the pressing cover is used to press the circuit board to ensure the contact between the at least one heat conductive member and the circuit board.

5. The test carrier according to claim 4, wherein: The base includes a bottom plate and two side plates, the two side plates are respectively erected on opposite sides of the bottom plate. When the pressing cover is covered on the base, the pressing cover abuts against the two side plates, and the at least one heat conducting member protrudes from the bottom plate.

6. The test carrier according to claim 4, wherein: The base has at least one first positioning structure, and the pressing cover has at least one second positioning structure. When the pressing cover is covered on the base, the at least one first positioning structure and the at least one second positioning structure are positioned with each other to prevent the pressing cover from opening relative to the base.

7. The test carrier according to claim 6, wherein: The at least one first positioning structure includes an elastic arm and a locking protrusion, the elastic arm includes a fixed end and a movable end opposite to each other, the fixed end is fixed to the base, and the locking protrusion protrudes from the movable end. The at least one second positioning structure is a locking hole. When the pressing cover is covered on the base, the locking protrusion is used to lock with the at least one second positioning structure.

8. The test carrier according to claim 4, wherein: The thermal conductivity of the base and the at least one heat conducting member is greater than the thermal conductivity of the pressing cover.

9. The test carrier according to claim 4, wherein: The housing further includes at least one pressing component. The at least one pressing component is disposed on the pressing cover and located in the accommodating space. The pressing cover is used to press the circuit board through the at least one pressing component.

10. The test carrier according to claim 9, wherein: The at least one pressing assembly includes a pressing plate, an elastic element and at least one limiting column. The pressing plate is movably arranged on the pressing cover through the elastic element. The pressing plate is used to press the circuit board. The limiting column includes a fixed end and a limiting end opposite to each other. The fixed end is fixed to the pressing cover. A portion of the pressing plate is located between the limiting end and the pressing cover and is limited by the limiting end.

11. A method for testing a circuit board assembly, characterized in that: Include: Placing a plurality of circuit board assemblies in an oven and placing the plurality of circuit board assemblies in a test state; Acquiring a temperature value of each of the plurality of circuit board components in the test state through a temperature sensor of each of the plurality of circuit board components; as well as According to the temperature value of each of the plurality of circuit board components, the on / off state of at least one channel of at least one heat source of each of the plurality of circuit board components in the test state is selectively switched.

12. The method for testing a circuit board assembly according to claim 11, wherein: Before the step of obtaining the temperature value of each of the plurality of circuit board components in the test state through the temperature sensor of each of the plurality of circuit board components, the method further includes: Obtaining an average temperature value of the plurality of circuit board assemblies in the test state through the plurality of temperature sensors of the plurality of circuit board assemblies; and The temperature of the oven is adjusted according to the average temperature value.

13. The method for testing a circuit board assembly according to claim 12, wherein: The step of adjusting the temperature of the oven according to the average temperature value comprises: The average temperature value is compared with a reference temperature value. If the difference between the average temperature value and the reference temperature value is within an error range, the step of obtaining the temperature value of each of the plurality of circuit board assemblies in the test state through the temperature sensor of each of the plurality of circuit board assemblies is performed. If the difference between the average temperature value and the reference temperature value is outside the error range, the temperature of the oven is adjusted according to the difference between the average temperature value and the reference temperature value, and the step of obtaining the average temperature value of the plurality of circuit board assemblies in the test state through the plurality of temperature sensors of the plurality of circuit board assemblies is performed again.

14. The method for testing a circuit board assembly according to claim 11, wherein: The at least one heat source of each of the plurality of circuit board assemblies has a plurality of channels. When the plurality of circuit board assemblies are in the test state, in the at least one heat source of each of the plurality of circuit board assemblies, some of the channels are set to an open state, and the remaining channels are set to a closed state. The step of selectively switching the on / off state of the at least one channel of the at least one heat source of each of the plurality of circuit board assemblies in the test state according to the temperature value of each of the plurality of circuit board assemblies comprises: The temperature value of each of the plurality of circuit board components is compared with at least one critical temperature value, and at least one of the plurality of channels set to an open state is closed or at least one of the plurality of channels set to a closed state is opened according to the comparison result.

15. The method for testing a circuit board assembly according to claim 11, wherein: The at least one heat source of each of the plurality of circuit board assemblies is a transimpedance amplifier.

16. A method for testing a circuit board assembly, characterized in that: Include: Placing at least one circuit board assembly in an oven and placing the at least one circuit board assembly in a test state; obtaining a temperature value of the at least one circuit board assembly in the test state through a temperature sensor of the at least one circuit board assembly; as well as The on / off state of at least one channel of at least one heat source of the at least one circuit board assembly in the test state is switched according to the temperature value.

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