Probe station and resistance adjustment method

Abstract

The present invention provides a probe station and resistance trimming method, relating to the technical field of thermal printhead equipment. The system comprises an industrial control system, a vacuum adsorption platform connected to the industrial control system, an XY-axis displacement mechanism, a Z-axis lifting mechanism, a rotation angle compensation mechanism, a visual positioning system, a needle washing device, a probe card, and a resistance trimming chassis. This device can improve resistance trimming uniformity and efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal print head equipment, and in particular to a probe station and a resistance adjustment method. Background Art

[0002] Existing thermal printheads require probes for resistance adjustment during resistance preparation to ensure that the resistance between each printed dot meets the required value. However, existing equipment suffers from poor uniformity, slow resistance adjustment, low stability, and poor reliability during resistance adjustment. Poor uniformity can lead to quality defects such as uneven ink density, while slow resistance adjustment affects adjustment efficiency. Furthermore, low stability and poor reliability can easily result in defective products. Summary of the Invention

[0003] The invention discloses a probe station, aiming to improve the problem of poor uniformity of an existing probe resistance adjustment mechanism.

[0004] The present invention adopts the following scheme:

[0005] A probe station includes an industrial control system and a vacuum adsorption platform connected to the industrial control system, an XY axis displacement mechanism, a Z axis lifting mechanism, a rotation angle compensation mechanism, a visual positioning system, a needle washing device, a probe card and a resistance adjustment chassis; wherein,

[0006] There are multiple resistance trimming probes on the probe card;

[0007] The vacuum adsorption platform is arranged on the XY axis displacement mechanism and is used to adsorb the thermal print head substrate to be adjusted in resistance;

[0008] The thermal print head substrate to be trimmed has a large number of hot spots densely distributed in the XY direction at preset intervals. By moving the XY coordinates, the hot spots to be tested are aligned one-to-one with the resistance trimming probes of the probe card to meet the positioning and alignment requirements. The hot spots on the thermal print head substrate are grouped and tested according to the number of probes on the probe card until all the hot spots are trimmed.

[0009] The visual positioning system is disposed above the vacuum adsorption platform and is used to identify and locate the hot spots of all thermal print heads and the conductive circuits of the hot spots on the substrate to be tested, so as to form an XY coordinate system. The deviation angle of the hot spots is calculated based on the XY coordinate system, which is used to calculate the angle of rotation of the probe card, thereby ensuring that the resistance adjustment probes of the probe card and the conductive circuits of the hot spots to be tested are consistent in the XY extension direction.

[0010] The Z-axis lifting mechanism is provided with a mounting platform suitable for mounting a probe card, and is suitable for driving the probe card to move up and down above the substrate so that each resistance adjustment probe on the probe card contacts the heating point electrode;

[0011] The mounting table is provided with a rotation angle compensation mechanism for driving the probe card to rotate according to the calculated angle of deviation of the hot spot in the XY direction; the XY axis displacement mechanism is suitable for driving the substrate to move under the probe card so that the hot spot electrode contacts the resistance adjustment probe on the probe card, ensuring that the resistance adjustment of each hot spot is completed one by one; a needle washing device is provided on the XY axis displacement mechanism, and the needle washing device is suitable for cleaning the probe needle tip on the probe card to remove oxides and contaminants and perform horizontal correction after passivation;

[0012] The probe card is connected to a resistance adjustment chassis, and the resistance adjustment chassis provides corresponding pulse voltages one by one according to the number of probes on the probe card to adjust the resistance of the corresponding heating point.

[0013] Furthermore, the visual positioning system includes a lifting device and a visual lens arranged on the lifting device. The visual lens is suitable for photographing and identifying the position of the hot spot electrode on the substrate, and can be moved to the probe position under the drive of the lifting device to obtain image information of the probe and transmit the image information to the industrial control system.

[0014] Furthermore, a fine-tuning mechanism is provided on the Z-axis lifting mechanism, and the fine-tuning mechanism is suitable for adjusting the height of the probe card; the industrial control system is configured to generate potential changes when testing the resistance adjustment based on the probe image information obtained by the visual lens and the industrial control system when testing the substrate. When the height of the bottom end of the probe is different and the potential fluctuation during the test exceeds a preset range, the needle washing device is driven to the bottom of the probe card for grinding to ensure the uniformity of the resistance adjustment.

[0015] Furthermore, the Z-axis lifting mechanism includes a lifting assembly arranged on a base, two guide rods parallel to the lifting direction of the lifting assembly, and the mounting platform is connected to the guide rods through a slider; the fine-tuning mechanism is fixed on the slider and one end of which is in contact and connected with the top of the lifting assembly, so that the lifting assembly acts on the fine-tuning mechanism, thereby driving the mounting platform to move up and down to adjust the initial height of the probe card.

[0016] Furthermore, a turntable for mounting a probe card is rotatably provided on the mounting platform, and gear teeth are provided on the turntable. The rotation angle compensation mechanism includes a rotating motor provided on the mounting platform, and the output shaft of the rotating motor is connected to a gear assembly suitable for matching the gear teeth, so as to drive the turntable to rotate through the rotating motor, thereby performing fine rotation adjustment of the probe card on the horizontal plane.

[0017] Furthermore, a probe card fixing mechanism is provided on the turntable, and the fixing mechanism includes a plurality of locking rods and fine-tuning rods. The locking rods are suitable for locking on two opposite sides of the probe card, and the fine-tuning rods are suitable for pressing the rear end position of the probe card. The probe card is kept level by the plurality of locking rods and fine-tuning rods.

[0018] Furthermore, an elastic fixing assembly is provided on one side of the mounting platform, and the elastic fixing assembly includes two pressing blocks installed on the cylinder, and each pressing block is provided with an elastic member to press the substrate onto the vacuum adsorption platform from above when the substrate is placed on the vacuum adsorption platform.

[0019] Furthermore, a spare conductive probe is provided on one side of the vacuum adsorption platform, and the spare conductive probe is connected to a flipping mechanism. The spare conductive probe is suitable for being flipped by the flipping mechanism when the substrate placed on the vacuum adsorption platform has no common electrode or the common electrode fails so that the spare conductive probe is connected to the electrode on the substrate.

[0020] Furthermore, a marking point mechanism is provided on the mounting table, and the marking point mechanism is provided on the side of the probe card to mark the marking point when the final resistance value of the heating point does not meet the preset target resistance value range.

[0021] The present invention also provides a resistance adjustment method, which uses the probe station and includes the following steps:

[0022] S1. Positioning: The visual positioning system is used to comprehensively scan the hot spots of the entire substrate, and then high-precision positioning and rotation angle compensation are performed to ensure that each probe can accurately contact the electrode of the hot spot for reading resistance and power-on resistance adjustment. Specifically, after the substrate is moved into place, the probe card moves down to measure the resistance at the hot spot. The industrial control system determines the actual resistance value measured and compares it with the set upper and lower resistance limits. When the preset upper and lower resistance limits are exceeded or the measured resistance value is abnormal, the probe card is lifted and moved left or right by a preset small displacement through the substrate, and then the needle is re-inserted to ensure that the probe is in accurate contact with the resistance adjustment electrode of the hot spot. If the resistance value read after repeated insertions exceeds a predetermined number, the location is marked.

[0023] S2. Resistance adjustment. The amount of resistance adjustment for each hot spot depends on the number of probes on the probe card. Each probe corresponds to a conductive circuit, and the conductive circuit is connected to the hot spot or the common electrode.

[0024] S21, before adjusting the resistance, make each probe of the probe card measure the resistance value of the standard resistor for calibration to ensure the accuracy of the resistance reading each time;

[0025] S22, when the measured actual resistance value is within the preset upper and lower limits, adjusting the resistance at each hot spot, the resistance value is adjusted by connecting the probe to the resistance adjustment chassis to output a pulse voltage to adjust the resistance value of each hot spot to be close to the preset target resistance value;

[0026] S23, repeating step S22 until the difference between the actual resistance value and the preset target resistance value is within the allowable difference range; in each cycle of step S22, when the difference between the actual resistance value of the corresponding hot spot and the preset target resistance value meets the standard, it is judged as qualified, and the qualified hot spot will not be energized for resistance adjustment in the next cycle; unqualified resistance values ​​are judged based on the resistance value of the last resistance adjustment after multiple cycles of power-on resistance adjustment, and those that do not meet the target resistance value are judged as bad and marked with a dot;

[0027] S3. Wash the probe. After repeating the above resistance adjustment process for a predetermined number of times, clean the probe tip to remove oxides and grind it flat so that the probe tip is on a horizontal surface to ensure the accuracy of the probe in measuring resistance each time.

[0028] Beneficial effects:

[0029] The above-mentioned method can solve the quality defects of existing thermal print heads, such as uneven ink density due to poor uniformity in resistance preparation, as well as the technical problems of slow resistance adjustment, low stability and poor reliability during resistance preparation. It can also achieve high-speed resistance adjustment, consistent rhythm and high utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of a probe station according to an embodiment of the present invention;

[0031] Figure 2 1 is a schematic structural diagram of an XY-axis displacement mechanism of a probe station according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic structural diagram of a resistance adjustment mechanism of a probe station according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic structural diagram of a probe station with a mounting platform hidden in an embodiment of the present invention;

[0034] Figure 5 This is a schematic structural diagram of a marking point mechanism of a probe station according to an embodiment of the present invention;

[0035] Icons: base 100, vacuum adsorption platform 110, XY-axis displacement mechanism 120, Z-axis lifting mechanism 130, lifting assembly 131, guide rod 132, fine-tuning mechanism 140, visual positioning system 150, probe card 160, needle washing device 170, flipping mechanism 181, spare conductive probe 182, mounting table 191, marking point mechanism 192, turntable 193, fixing mechanism 194, locking rod 1941, fine-tuning rod 1942, elastic fixing assembly 195, rotation angle compensation mechanism 196. DETAILED DESCRIPTION

[0036] Example 1

[0037] Combine Figures 1 to 5As shown, this embodiment provides a probe station, including an industrial control system and a vacuum adsorption platform 110 connected to the industrial control system, an XY axis displacement mechanism 120, a Z axis lifting mechanism 130, a rotation angle compensation mechanism 196, a visual positioning system 150, a needle washing device 170, a probe card 160, a flip electrode and a resistance adjustment chassis; wherein, there are multiple resistance adjustment probes on the probe card 160; the vacuum adsorption platform 110 is arranged on the XY axis displacement mechanism 120, and is used to adsorb the thermal print head substrate to be adjusted in resistance, and the thermal print head substrate to be adjusted in resistance is arranged in the XY direction according to a preset spacing. , densely covered with a large number of hot spots, by moving the XY coordinates, the hot spots to be tested are made to form a one-to-one correspondence with the resistance adjustment probes of the probe card 160 to meet the requirements of positioning and alignment, and the hot spots on the thermal print head substrate are grouped and tested according to the number of probes on the probe card 160 until all the resistance adjustment is completed; the visual positioning system 150 is set above the vacuum adsorption platform 110 to identify the hot spots of all thermal print heads on the substrate to be tested and the conductive circuits of the hot spots to form an XY coordinate system, and the deviation angle of the hot spots is calculated based on the XY coordinate system to calculate the required rotation The angle of the probe card 160 is adjusted so that the resistance adjustment probe of the probe card 160 is consistent with the conductive circuit of the hot spot to be measured in the XY extension direction, ensuring that the resistance adjustment probe can accurately dock with the hot spot; the Z-axis lifting mechanism 130 is provided with a mounting platform 191 suitable for mounting the probe card 160, and is suitable for driving the probe card 160 to rise and fall above the substrate so that each resistance adjustment probe on the probe card 160 contacts the hot spot electrode; the mounting platform 191 is provided with a rotation angle compensation mechanism 196 for driving the probe card 160 to rotate a predetermined angle; the XY-axis displacement mechanism 120 is suitable for The substrate is driven to move under the probe card 160 so that the hot point electrode contacts the resistance adjustment probe on the probe card 160, ensuring that the resistance of each hot point is adjusted one by one; a needle washing device 170 is provided on the XY axis displacement mechanism 120, and the needle washing device 170 is suitable for cleaning the probe needle tip on the probe card 160 to remove oxides, contaminants or to perform horizontal correction on the probe after passivation; the probe card 160 is connected to the resistance adjustment chassis, and the resistance adjustment chassis provides corresponding pulse voltages one by one according to the number of probes on the probe card for adjusting the resistance value of the corresponding hot point.

[0038] Combine Figures 1 to 2As shown, in this embodiment, the XY-axis displacement mechanism 120 and the Z-axis lifting mechanism 130 are arranged on the base 100, and the vacuum adsorption platform 110 is detachably arranged on the XY-axis displacement mechanism 120. The vacuum adsorption platform 110 is also provided with clamping devices on all sides. On the one hand, it can be used to correct the position of the substrate placed on the vacuum adsorption platform 110, and on the other hand, it is also used for auxiliary clamping to avoid displacement during machine displacement or resistance adjustment. The needle washing device 170 is arranged on the XY-axis displacement mechanism 120, and is used to move to the bottom of the probe card 160 when needle washing is required, and to move so that the probe on the probe card 160 is smoothed on the needle washing device 170. In one embodiment, the needle washing device 170 can be sandpaper, which is used to smooth the end of the probe. Preferably, a blowing device is provided on one side of the sandpaper, which can blow air while washing the needle to prevent probe debris from adhering to the end of the probe and affecting subsequent testing and resistance adjustment effects.

[0039] In this embodiment, a large number of hot spots are densely distributed on the thermal print head substrate to be adjusted in resistance in the XY direction according to a preset spacing. By moving the XY coordinates, the hot spots to be tested are made to form a one-to-one correspondence with the resistance adjustment probes of the probe card 160 to meet the requirements of positioning and alignment, and the hot spots on the thermal print head substrate are grouped and tested according to the number of probes of the probe card 160 until all resistance adjustment is completed. The visual positioning system 150 can be used to identify the hot spots of all thermal print heads on the substrate to be tested and the conductive circuits of the hot spots to form an XY coordinate system, and the deviation angle of the hot spots is calculated from this XY coordinate system. The hot spot coordinate data obtained by the visual positioning system 150 is used to control the XY axis displacement mechanism 120 and the rotation angle compensation mechanism 196 to adjust the position through the industrial control system, so that the hot spots are accurately docked with the resistance adjustment probes.

[0040] Combine Figures 1 to 4As shown, the Z-axis lifting mechanism 130 includes a lifting assembly 131 disposed on the base 100, two guide rods 132 parallel to the lifting direction of the lifting assembly 131, and the mounting platform 191 is connected to the guide rods 132 via a slider; the fine-tuning mechanism 140 is fixed to the slider and one end of which is in contact with the top of the lifting assembly 131, so that the lifting assembly 131 acts on the fine-tuning mechanism 140, thereby driving the mounting platform 191 to move up and down. Here, the fine-tuning mechanism 140 can be adjusted by a high-precision gear set in conjunction with a motor-controlled micrometer assembly. The lifting assembly 131 includes a linear motor, which is disposed on one side of the two guide rods 132 and is used to drive the slider to rise. When the extended shaft of the linear motor retracts, the slider and the mounting platform 191 descend due to their own gravity. The end of the micrometer assembly on the fine-tuning mechanism 140 contacts the end of the extended shaft of the linear motor, which is used to support the slider. Therefore, when the micrometer assembly is adjusted, the mounting platform 191 and the probe card 160 on the mounting platform 191 can be controlled to fine-tune up and down. This is because the accuracy of the linear motor or other lifting mechanism is difficult to meet the requirements of adjusting the fine spacing. When the distance between the probe on the probe card 160 and the hot spot on the substrate is very small, the potential fluctuation will be large during the resistance measurement, and the measured resistance value will also fluctuate, and the fluctuation is large. The reason for the fluctuation may be that the contact point between the probe and the hot spot is small, or it may be that the probe tip descends to a large height, causing the tip to bend (the tip is flexible). At this time, if the linear motor is directly activated to lift and lower, the probe may completely separate from the substrate, or the probe may move downward a large amount, causing the probe to be damaged. Therefore, by providing a fine-tuning mechanism 140 for adjustment, the accuracy can reach 1um, which can effectively prevent the occurrence of the above situation.

[0041] Combine Figures 1 to 5As shown, the visual positioning system 150 includes a lifting device and a visual lens arranged on the lifting device, the visual lens is suitable for photographing and identifying the position of the hot spot electrode on the substrate, and can be moved to the probe position under the drive of the lifting device to obtain the image information of the probe, and transmit the image information to the industrial control system. The visual lens is provided with a fine-tuning component for adjusting the position and height of the visual lens. After a period of use and after the rotation angle compensation mechanism 196 is adjusted, when the industrial control system can still detect that the resistance or potential fluctuation of some of the measured hot spots exceeds the preset range, it may be that the probe card 160 has not moved into place. At this time, the visual lens can be driven to descend to the probe position for photographing and identification. According to the probe image information obtained by the visual lens, when it is found that the probe is not completely in contact with the hot spot of the substrate, the probe card 160 is driven to descend a certain scale distance through the fine-tuning mechanism 140 until the resistance or potential fluctuation detected by the industrial control system becomes smaller, or the fluctuation range is within the preset range; if the visual lens recognizes that the needle tip of the probe is partially bent, then This means that the probe card 160 has descended to a large height. In this case, the fine-tuning mechanism 140 can be used to control the probe card 160 to rise a certain distance until the resistance or potential fluctuation detected by the industrial control system becomes smaller, or the fluctuation range is within the preset range. If the fine-tuning mechanism 140 cannot reduce the resistance or potential fluctuation detected by the industrial control system, or cannot make the fluctuation range within the preset range, it means that the probes on the probe card 160 are of different lengths. At this time, the needle washing device 170 is driven to the bottom of the probe card 160 for grinding and cleaning to ensure that the needle tip height of each probe is consistent, thereby improving the uniformity of the resistance value when adjusting the resistance. In addition, the needle washing device 170 can also be used to perform overall correction after the resistance adjustment probe is passivated to improve the accuracy of the resistance adjustment.

[0042] Combine Figures 1 to 5As shown, a turntable 193 for mounting the probe card 160 is rotatably mounted on the mounting platform 191. The turntable 193 is provided with gear teeth. The rotation angle compensation mechanism 196 includes a rotary motor mounted on the mounting platform 191. The output shaft of the rotary motor is connected to a gear assembly adapted to mate with the gear teeth. The rotary motor drives the turntable 193 to rotate, thereby fine-tuning the probe card 160 left and right. A probe card 160 fixing mechanism 194 is mounted on the turntable 193. The fixing mechanism 194 includes a plurality of locking rods 1941 and fine-tuning rods 1942. The locking rods 1941 are adapted to lock opposite sides of the probe card 160. The fine-tuning rods are adapted to compress the rear end of the probe card 160. The locking rods 1941 and fine-tuning rods 1942 are used to maintain the probe card 160 level. In this embodiment, the probe card 160 is mounted within the fixing mechanism 194, and the locking rod 1941 is adjusted to lock it, and then fine-tuned using the fine-adjustment rod 1942 to maintain the probe card 160 level within the fixing mechanism 194. An elastic fixing assembly 195 is provided on one side of the mounting platform 191. The elastic fixing assembly 195 comprises two pressure blocks mounted on a cylinder, each of which is equipped with an elastic member to press the substrate against the vacuum adsorption platform 110 from above when the substrate is placed on the vacuum adsorption platform 110. A marking mechanism 192 is provided on the mounting platform 191. The marking mechanism 192 is located on the side of the probe card 160 and is used to mark a hot spot at a corresponding position on the substrate when abnormal resistance is detected.

[0043] In this embodiment, by providing a rotation angle compensation mechanism 196, it can cooperate with the fine-tuning mechanism 140. When the difference between the measured actual resistance value and the set target resistance value exceeds the preset target value or the measured resistance value reading is abnormal, the probe card 160 is lifted by the lifting mechanism, and then the rotation angle compensation mechanism 196 controls the probe card 160 to move left and right respectively for fine-tuning. The fine-tuning range is about 1 to 10 μm, and the left and right fine-tuning needles are repeated. If the resistance reading is normal and the difference between the actual resistance value and the set target resistance value is within the preset target value allowable range, the resistance can be adjusted. If the reading is still not normal after repeated fine-tuning or the difference between the actual resistance value and the set target resistance value still exceeds the preset target value, it is determined that there is a major problem with the hot spot in the area, and the marking mechanism 192 is used to mark the hot spot without performing the resistance adjustment action. Here, the rotation angle compensation mechanism 196 can adjust the problem of the probe not being accurately aligned with the hot spot due to the position error between the probe and the hot spot, and repeat the left and right fine-tuning to ensure that the probe is accurately aligned with the hot spot. During the test, the resistance adjustment chassis collects resistance values ​​in real time.

[0044] Combine Figure 1 and Figure 2As shown, in another embodiment, a spare conductive probe 182 is provided on one side of the vacuum adsorption platform 110. The spare conductive probe 182 is connected to the flip mechanism 181. The spare conductive probe 182 is suitable for flipping through the flip mechanism 181 when the substrate to be adjusted for resistance placed on the vacuum adsorption platform 110 does not have a common electrode or the common electrode fails so that the spare conductive probe 182 is connected to the electrode on the substrate. Here, by providing the spare conductive probe 182, the mechanism can adapt to different types of substrate testing, in particular, it can be applied to substrates with common electrodes and substrates without common electrodes. Here, when the substrate with a common electrode is adjusted for resistance, the common electrode on the substrate is electrically connected to the resistance adjustment chassis, and the probe is used as another electrode to form a loop with the common electrode, so that the resistance of the hot point can be measured, and then the resistance adjustment chassis outputs a pulse voltage for resistance adjustment. When adjusting the resistance, each hot point is adjusted independently from one end to the other. When the resistance value meets the requirements, the hot point does not need to be adjusted. For hot points with larger resistance values, pulse voltage is required for resistance adjustment. The method of adjusting resistance by pulse voltage is a prior art and will not be described in detail here. When the substrate does not have a common electrode, the flip mechanism 181 flips the spare conductive probe 182 to a position close to the substrate, so that the substrate is connected to the spare conductive probe 182, and the spare conductive probe 182 serves as one of the electrodes of the substrate.

[0045] This solution sets the fine-tuning mechanism 140 as the rotation angle compensation mechanism 196, which can cooperate with the industrial control system to fine-tune the position of the probe card 160 before adjusting the resistance, thereby effectively solving the problem of poor resistance adjustment reliability. At the same time, in conjunction with the needle washing device 170, it can improve the uniformity of resistance adjustment and solve the quality defects of existing thermal print heads in the uneven thickness of printed ink dots due to poor uniformity in resistance preparation.

[0046] Example 2

[0047] The present invention also provides a resistance adjustment method, which uses the above-mentioned probe station and includes the following steps:

[0048] S1. Positioning: The visual positioning system is used to comprehensively scan the hot spots of the entire substrate, and then high-precision positioning and rotation angle compensation are performed to ensure that each probe can accurately contact the electrode of the hot spot for reading resistance and power-on resistance adjustment. Specifically, after the substrate is moved into place, the probe card moves down to measure the resistance at the hot spot. The industrial control system determines the actual resistance value measured and compares it with the set upper and lower resistance limits. When the preset upper and lower resistance limits are exceeded or the measured resistance value is abnormal, the probe card is lifted and moved left or right by a preset small displacement through the substrate, and then the needle is re-inserted to ensure that the probe is in accurate contact with the resistance adjustment electrode of the hot spot. If the resistance value read after repeated insertions exceeds a predetermined number, the location is marked.

[0049] S2. Resistance adjustment. The amount of resistance adjustment for each hot spot depends on the number of probes on the probe card. Each probe corresponds to a conductive circuit, and the conductive circuit is connected to the hot spot or the common electrode.

[0050] S21, before adjusting the resistance, make each probe of the probe card measure the resistance value of the standard resistor for calibration to ensure the accuracy of the resistance reading each time;

[0051] S22, when the measured actual resistance value is within the preset upper and lower limits, adjusting the resistance at each hot spot, the resistance value is adjusted by connecting the probe to the resistance adjustment chassis to output a pulse voltage to adjust the resistance value of each hot spot to be close to the preset target resistance value;

[0052] S23, repeating step S22 until the difference between the actual resistance value and the preset target resistance value is within the allowable difference range; in each cycle of step S22, when the difference between the actual resistance value of the corresponding hot spot and the preset target resistance value meets the standard, it is judged as qualified, and the qualified hot spot will not be energized for resistance adjustment in the next cycle; unqualified resistance values ​​are judged based on the resistance value of the last resistance adjustment after multiple cycles of power-on resistance adjustment, and those that do not meet the target resistance value are judged as bad and marked with a dot;

[0053] S3. Wash the probe. After repeating the above resistance adjustment process for a predetermined number of times, clean the probe tip to remove oxides and grind it flat so that the probe tip is on a horizontal surface to ensure the accuracy of the probe in measuring resistance each time.

[0054] In this embodiment, in step S23, after multiple cycles of resistance adjustment, the resistance value of the last adjustment is used for determination, which is the first determination. If the first determination is unqualified, the probe card is lifted and slightly displaced to the left for a second resistance measurement and adjustment, which is the second determination. If the second determination is still unqualified, the probe card is lifted and the unqualified hot spot is returned to the initial position, and then slightly displaced to the right for a third resistance measurement and adjustment. If any of the three determinations are qualified, the product is deemed qualified. If the resistance value is still unqualified after the third determination, a dot mark is performed. This solution can reduce the probability of false detection and reduce substrate waste caused by false detection.

[0055] In this embodiment, when several probe stations are provided on the entire device, cross-testing is performed within a predetermined time, that is, after resistance adjustment is completed on one of the probe stations, it is transferred to another probe station for testing, and only testing is performed on the other probe station without resistance adjustment, so as to determine the accuracy of the resistance value of the substrate adjusted by the probe station. If the resistance values ​​measured between the two probe stations are significantly different, it means that one of the probe stations has a problem and needs to be repaired.

[0056] In this embodiment, during the testing phase, if an abnormal resistance value is detected, fine-tuning can be performed in four directions (up, down, left, and right) using the rotation angle compensation mechanism 196 and the fine-tuning mechanism 140 to prevent abnormal resistance values ​​due to position errors. If, after adjustments using the fine-tuning mechanism 140 and the rotation angle compensation mechanism 196, the resistance value of a certain hot spot still exhibits an abnormality or exhibits significant resistance fluctuations, the probe tip on the probe card 160 is smoothed using the needle cleaning device 170 to address the issue of inaccurate detection of certain hot spots due to varying probe heights.

[0057] During the resistance adjustment stage, the resistance is adjusted through multiple cycles of needle insertion, and the resistance value of the last adjustment is used to determine whether it meets the target resistance value. If it does not meet the target resistance value, a mark is made.

[0058] It should be noted that in this embodiment, each substrate includes multiple thermal print heads, each with multiple heating points. The probe card 160 adjusts the resistance of one of the thermal print heads at a time. If a non-compliant thermal print head is detected, it is marked and the remaining thermal print heads are tested for resistance adjustment. After a certain number of resistance adjustments, the probe tips are cleaned to remove oxides and ground flat, ensuring they are level.

[0059] Through the solution of this embodiment, better resistance uniformity can be achieved, so that the color saturation of the ink dots in the printing effect is guaranteed and the printing is refined, and high-speed resistance adjustment, consistent beats and high utilization rate can be achieved.

[0060] It should be understood that the above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention.

[0061] The above description of the drawings used in the implementation manner only shows certain embodiments of the present invention and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without making any creative efforts.

Claims

1. A probe station, characterized in that It includes an industrial control system and a vacuum adsorption platform, an XY axis displacement mechanism, a Z axis lifting mechanism, a rotation angle compensation mechanism, a visual positioning system, a needle washing device, a probe card and a resistance adjustment chassis connected to the industrial control system; wherein, There are multiple resistance trimming probes on the probe card; The vacuum adsorption platform is arranged on the XY axis displacement mechanism and is used to adsorb the thermal print head substrate to be adjusted in resistance; The thermal print head substrate to be trimmed has a large number of hot spots densely distributed in the XY direction at preset intervals. By moving the XY coordinates, the hot spots to be tested are aligned one-to-one with the resistance trimming probes of the probe card to meet the positioning and alignment requirements. The hot spots on the thermal print head substrate are grouped and tested according to the number of probes on the probe card until all the hot spots are trimmed. The visual positioning system is disposed above the vacuum adsorption platform and is used to identify and locate the hot spots of all thermal print heads and the conductive circuits of the hot spots on the substrate to be tested, so as to form an XY coordinate system. The deviation angle of the hot spots is calculated based on the XY coordinate system, which is used to calculate the angle of rotation of the probe card, thereby ensuring that the resistance adjustment probes of the probe card and the conductive circuits of the hot spots to be tested are consistent in the XY extension direction. The Z-axis lifting mechanism is provided with a mounting platform suitable for mounting a probe card, and is suitable for driving the probe card to move up and down above the substrate so that each resistance adjustment probe on the probe card contacts the heating point electrode; The mounting table is provided with a rotation angle compensation mechanism for driving the probe card to rotate according to the calculated angle of deviation of the hot spot in the XY direction; the XY axis displacement mechanism is suitable for driving the substrate to move under the probe card so that the hot spot electrode contacts the resistance adjustment probe on the probe card, ensuring that the resistance adjustment of each hot spot is completed one by one; a needle washing device is provided on the XY axis displacement mechanism, and the needle washing device is suitable for cleaning the probe needle tip on the probe card to remove oxides and contaminants and perform horizontal correction after passivation; The probe card is connected to a resistance adjustment chassis, and the resistance adjustment chassis provides corresponding pulse voltages one by one according to the number of probes on the probe card to adjust the resistance of the corresponding heating point.

2. The probe station according to claim 1, characterized in that The visual positioning system includes a lifting device and a visual lens arranged on the lifting device. The visual lens is suitable for photographing and identifying the position of the hot point electrode on the substrate, and can be moved to the probe position under the drive of the lifting device to obtain image information of the probe and transmit the image information to the industrial control system.

3. The probe station according to claim 2, characterized in that The Z-axis lifting mechanism is provided with a fine-tuning mechanism, which is suitable for adjusting the height of the probe card; the industrial control system is configured to generate potential changes when testing resistance adjustment based on the probe image information obtained by the visual lens and the industrial control system when testing the substrate. When the height of the bottom end of the probe is different and the potential fluctuation during the test exceeds a preset range, the needle washing device is driven to the bottom of the probe card for grinding to ensure the uniformity of the resistance adjustment.

4. The probe station according to claim 3, characterized in that The Z-axis lifting mechanism includes a lifting component arranged on a base and two guide rods parallel to the lifting direction of the lifting component. The mounting platform is connected to the guide rods through a slider; the fine-tuning mechanism is fixed on the slider and one end of the slider is in contact with the top of the lifting component, so that the lifting component acts on the fine-tuning mechanism, thereby driving the mounting platform to move up and down to adjust the initial height of the probe card.

5. The probe station according to claim 1, characterized in that A turntable for mounting a probe card is rotatably provided on the mounting platform, and gear teeth are provided on the turntable. The rotation angle compensation mechanism includes a rotating motor provided on the mounting platform, and the output shaft of the rotating motor is connected to a gear assembly suitable for matching the gear teeth, so that the turntable is driven to rotate by the rotating motor, thereby performing fine rotation adjustment of the probe card on the horizontal plane.

6. The probe station according to claim 5, characterized in that A probe card fixing mechanism is provided on the turntable, and the fixing mechanism includes a plurality of locking rods and fine-tuning rods. The locking rods are suitable for locking on two opposite sides of the probe card, and the fine-tuning rods are suitable for pressing the rear end position of the probe card. The probe card is kept level by the plurality of locking rods and fine-tuning rods.

7. The probe station according to claim 5, characterized in that An elastic fixing assembly is provided on one side of the mounting platform. The elastic fixing assembly includes two pressing blocks installed on a cylinder. Each pressing block is provided with an elastic member to press the substrate onto the vacuum adsorption platform from above when the substrate is placed on the vacuum adsorption platform.

8. The probe station according to claim 5, characterized in that A spare conductive probe is provided on one side of the vacuum adsorption platform and is connected to a flipping mechanism. The spare conductive probe is suitable for being flipped by the flipping mechanism when a substrate placed on the vacuum adsorption platform has no common electrode or the common electrode fails so that the spare conductive probe is connected to the electrode on the substrate.

9. The probe station according to claim 5, characterized in that The mounting table is provided with a marking point mechanism, which is arranged on the side of the probe card to mark the marking point when the final resistance value of the heating point does not meet the preset target resistance value range.

10. A resistance adjustment method, characterized in that: The method of using the probe station according to any one of claims 1 to 9 comprises the following steps: S1. Positioning: The visual positioning system is used to comprehensively scan the hot spots of the entire substrate, and then high-precision positioning and rotation angle compensation are performed to ensure that each probe can accurately contact the electrode of the hot spot for reading resistance and power-on resistance adjustment. Specifically, after the substrate is moved into place, the probe card moves down to measure the resistance at the hot spot. The industrial control system determines the actual resistance value measured and compares it with the set upper and lower resistance limits. When the preset upper and lower resistance limits are exceeded or the measured resistance value is abnormal, the probe card is lifted and moved left or right by a preset small displacement through the substrate, and then the needle is re-inserted to ensure that the probe is in accurate contact with the resistance adjustment electrode of the hot spot. If the resistance value read after repeated insertions exceeds a predetermined number, the location is marked. S2. Resistance adjustment. The amount of resistance adjustment for each hot spot depends on the number of probes on the probe card. Each probe corresponds to a conductive circuit, and the conductive circuit is connected to the hot spot or the common electrode. S21, before adjusting the resistance, make each probe of the probe card measure the resistance value of the standard resistor for calibration to ensure the accuracy of the resistance reading each time; S22, when the measured actual resistance value is within the preset upper and lower limits, adjusting the resistance at each hot spot, the resistance value is adjusted by connecting the probe to the resistance adjustment chassis to output a pulse voltage to adjust the resistance value of each hot spot to be close to the preset target resistance value; S23, repeating step S22 until the difference between the actual resistance value and the preset target resistance value is within the allowable difference range; in each cycle of step S22, when the difference between the actual resistance value of the corresponding hot spot and the preset target resistance value meets the standard, it is judged as qualified, and the qualified hot spot will not be energized for resistance adjustment in the next cycle; unqualified resistance values ​​are judged based on the resistance value of the last resistance adjustment after multiple cycles of power-on resistance adjustment, and those that do not meet the target resistance value are judged as bad and marked with a dot; S3. Wash the probe. After repeating the above resistance adjustment process for a predetermined number of times, clean the probe tip to remove oxides and grind it flat so that the probe tip is on a horizontal surface to ensure the accuracy of the probe in measuring resistance each time.

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