A method and system for detecting jitter of a motion platform

Abstract

The application provides a jitter detection method and system for a motion platform. A uniform motion area of the motion platform is used as a jitter detection area. The jitter detection area is divided into multiple sub-areas. Each sub-area is divided into multiple jitter detection areas. Actual clock pulse information corresponding to position information of a grating ruler read by a reading head in each jitter detection area is detected through a stable clock pulse. A first detection value of the jitter detection area is obtained according to the actual clock pulse information of each jitter detection area. A second detection value in the corresponding sub-area is obtained according to the first detection value of the jitter detection area. The second detection values of the sub-areas are integrated to obtain a third detection value of the jitter detection area. The third detection value is compared with a jitter threshold value to determine whether the motion platform is jittering. The jitter information of the motion platform is obtained in real time and quickly, and the motion platform is corrected in time to avoid workpiece scrap.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of processing equipment, and particularly relates to detection of shaking of a moving platform of a processing equipment. BACKGROUND

[0002] A moving platform of a processing equipment is usually driven by a linear motor, so that the moving platform can move linearly. For example, for an exposure processing equipment of a printed circuit board, a workpiece is placed on the moving platform, and the moving platform is driven by a linear motor to move linearly to the position below an exposure lens for scanning exposure operation.

[0003] Currently, during debugging of the processing equipment, motor parameters of the motor are modified to make the speed loop, position loop and current loop of the moving platform reach expected values, and the motor parameter data is saved for subsequent processing production. In the subsequent processing production, defects of the processed products are found to discover shaking of the moving platform, and the motor parameters are again modified through debugging for subsequent processing production. Due to the lag in discovering the shaking of the moving platform, a large number of processed workpieces are scrapped, and production cost is increased. SUMMARY

[0004] The present application aims to provide a method for detecting shaking of a moving platform in real time to avoid batch waste of processed workpieces.

[0005] To solve the above problem, the present application provides a method for detecting shaking of a moving platform, the moving platform comprising a grating ruler and a reading head, a uniform motion area of the moving platform is taken as a shaking detection area, the shaking detection area is divided into a plurality of sub-areas, each sub-area is divided into a plurality of shaking detection areas, actual clock pulse information corresponding to position information of the grating ruler read by the reading head in each shaking detection area is detected through stable clock pulses, a first detection value of the shaking detection area is obtained according to the actual clock pulse information of each shaking detection area, a second detection value in the corresponding sub-area is obtained according to the first detection value of the shaking detection area, the second detection values of the sub-areas are integrated to obtain a third detection value of the shaking detection area, and the third detection value is compared with a shaking threshold value to determine whether the moving platform shakes.

[0006] Further, the first detection value is compared with ideal clock pulse information to determine whether it exceeds the shaking threshold value range, and if it exceeds the shaking threshold value range, the count is 1, and if it does not exceed the shaking threshold value range, the count is 0.

[0007] Further, the second detection value is a cumulative value of the first detection values in the current sub-area and all sub-areas before the current sub-area.

[0008] Further, the third detection value is the number of different values in the second detection values.

[0009] Further, the first detection value is the actual clock pulse information with the smaller clock pulse information obtained in the sub-region.

[0010] Further, the second detection value is the smallest clock pulse information obtained in each sub-region.

[0011] Further, the third detection value is the speed range value or clock information range value obtained according to all second detection values.

[0012] Further, the actual clock pulse information is the number or time of the clock pulse corresponding to the jitter precision detection region.

[0013] The jitter detection system applied to the jitter detection method comprises a main control unit and a jitter detection unit, the jitter detection unit comprises a clock, a jitter precision region calculation unit and a sub-region data storage unit, the main control unit controls the jitter detection unit, the main control unit is used for setting the parameters of the motion platform, the detection region, the sub-region, the jitter detection region and the jitter threshold value, and judging according to the third detection value obtained according to the second detection value output by the jitter detection unit, the clock is used for outputting stable clock pulse, the jitter precision region calculation unit is used for sequentially obtaining the first detection value of the jitter precision region, and obtaining the second detection value in units of sub-regions, and the sub-region data storage unit is used for respectively corresponding storage of the second detection value.

[0014] Further, the jitter precision region calculation unit comprises a comparator and a counter, and the result of the comparator is counted by the counter.

[0015] Further, the jitter precision region calculation unit comprises a comparator, and the comparator is used for comparing the obtained actual clock pulse information with the smaller clock pulse information obtained in the sub-region to obtain the first detection value.

[0016] The direct writing exposure system applied to the jitter detection system, the direct writing exposure system comprises a motion platform, a main control system, a synchronization board and a spatial light modulator control board (DGB), the main control system controls the motion platform, the synchronization board and the spatial light modulator control board (DGB), the main control system comprises the main control unit of the jitter detection system, and the jitter detection unit of the jitter detection system is arranged on the synchronization board.

[0017] Compared with the prior art, through the jitter detection method and system, the motion platform can be detected in real time during the workpiece processing of the motion platform, and the workpiece can be avoided from being scrapped due to the jitter of the motion platform. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the motion platform.

[0019] Figure 2 This is a schematic diagram of the detection area.

[0020] Figure 3 This is a schematic diagram of the sub-region.

[0021] Figure 4 A schematic diagram of an embodiment for determining the jitter detection area.

[0022] Figure 5 A flowchart illustrating an embodiment for determining the jitter detection area.

[0023] Figure 6 This is a schematic diagram of an embodiment of a jitter detection system.

[0024] Figure 7 This is a schematic diagram of another embodiment for sub-region detection and determination.

[0025] Figure 8 This is a schematic diagram of another embodiment of the jitter detection system.

[0026] Figure 9 This is a schematic diagram of a jitter detection system applied to a direct-write exposure system. Detailed Implementation

[0027] To make the technical solution of the present invention clearer, embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the specific description of the embodiments is only for teaching those skilled in the art how to implement the present invention, and is not intended to exhaustively describe all feasible methods of the present invention, nor is it intended to limit the specific scope of the present invention.

[0028] like Figure 1 As shown, the motion platform includes a carrying platform, a drive mechanism, a control mechanism, and a position detection mechanism. The control mechanism sends commands to the drive mechanism, instructing the drive mechanism to move the carrying platform. The drive mechanism includes a platform controller and a drive motor; the position detection mechanism includes a grating ruler and a reading head. When the drive motor moves the carrying platform, it moves the reading head along the grating ruler. The platform controller obtains the position information of the grating ruler through the reading head. Based on the resolution of the grating ruler (the smallest change that the grating ruler can recognize), the reading head outputs a position data signal for each minimum change it moves.

[0029] When performing vibration detection on the motion platform, a stable clock is used to keep track of the time. The actual detection time is compared with the ideal detection time to determine whether the motion platform is vibrating.

[0030] like Figures 2-3 As shown, the vibration detection of a motion platform moving at a constant speed is illustrated. First, the detection area of ​​the motion platform is determined. The detection area is positionally detected using a grating ruler, and then divided into M sub-regions, each with the same length. Each sub-region is then divided into J vibration accuracy detection regions, each with the same length. The length d of each vibration accuracy detection region is an integer multiple of the resolution of the grating ruler. Alternatively, the length of the vibration accuracy detection region can be determined first, followed by the lengths of the sub-regions.

[0031] Based on the defined jitter accuracy regions and the motion platform's operating path, the actual number of clock pulses of the motion platform is sequentially obtained. For each sub-region, the actual number of clock pulses within the jitter accuracy region is sequentially obtained. This actual number of clock pulses is compared with the previously obtained number of clock pulses or a set range of clock pulses to obtain a first detection value. The second detection value for the corresponding sub-region is then obtained based on the first detection value of the jitter detection region. A third detection value for the detection region is determined based on the second detection value of each sub-region, and the motion platform is judged to be jittery based on the third detection value.

[0032] The comparison method for the actual number of clock pulses obtained from the jitter accuracy region in each sub-region can be as follows: compare it with the ideal number of clock pulses to determine if it is within the difference threshold range; if it exceeds the difference threshold range, perform a count; or directly obtain the clock pulse count threshold range based on the ideal clock pulse count, compare the actual number of clock pulses with the clock pulse count threshold range, and perform a count for jitter accuracy regions that exceed the threshold range. The jitter accuracy regions within each sub-region are cumulatively counted, and each sub-region of the detection area is cumulatively counted, with each sub-region outputting a count value corresponding to the current sub-region. Based on the count value of each sub-region, determine the number of different values ​​among the M count values ​​obtained from the sub-regions in the detection area. Compare the number of different values ​​with the jitter threshold; if it is not greater than the jitter threshold, it is considered normal; if it is greater than the jitter threshold, it is considered jitter. The jitter threshold is set according to the accuracy required for the processed product.

[0033] The ideal number of clock pulses N0 is obtained based on the frequency F of the clock pulse, the ideal speed V of the motion platform, and the length d of the jitter accuracy detection area. The calculation formula is N0 = F × d / V.

[0034] The comparison manner of the actual clock pulse number obtained by each sub-region can adopt the manner of comparing the actual clock pulses obtained by two adjacent jitter precision regions, outputting the actual clock pulse number obtained by the jitter precision region with smaller value, sequentially comparing, and outputting the minimum actual clock pulse number in the sub-region after detecting all the jitter precision regions in the sub-region; or the comparison manner of comparing the actual clock pulses obtained by two adjacent jitter precision regions, outputting the actual clock pulse number obtained by the jitter precision region with larger value, sequentially comparing, and outputting the maximum actual clock pulse number in the sub-region after detecting all the jitter precision regions in the sub-region. According to the M clock pulse numbers obtained by each sub-region, the speed value corresponding to each clock pulse number is calculated, and whether the speed value in the detection interval is within the allowable fluctuation range is judged. If it is within the fluctuation range, it is determined to be normal, and if it is not within the fluctuation range, it is determined to be jitter. The fluctuation range is the jitter threshold, and the fluctuation range is the speed interval set according to the required precision of the processed product or the clock pulse number interval obtained according to the speed interval. The speed value Vn corresponding to the clock pulse number Nn is obtained by the frequency F of the clock pulse and the length d of the jitter precision detection region, and the calculation formula is Vn=F×d / Nn. The fluctuation range is the jitter threshold.

[0035] As Figures 4-6 The first embodiment is described in detail below. The motion line of the motion platform is divided into an acceleration section, a uniform speed section and a deceleration section, and the uniform motion speed is set as V. The detection region is located in the uniform speed section of the motion line and has a starting position and an end position. The detection region is divided into M sub-regions, which are sub-region A1, sub-region A2, sub-region A3, …, and sub-region Am. The length of each sub-region is a. Each sub-region is sequentially divided into J jitter precision regions, which are jitter precision region D Ai1 , jitter precision region D Ai2 , jitter precision region D Ai3 ……, and jitter precision region D Aij , where i is the number of the sub-region corresponding to the jitter precision region, and the length of each jitter precision detection region is d. The frequency of the clock pulse for detecting the actual clock pulse number when the motion platform moves at a uniform speed is F. As described above, the ideal clock pulse number N0=F×d / V of the jitter detection region is obtained according to the set uniform motion speed V of the motion platform, the determined frequency F of the clock pulse, and the length d of the jitter precision detection region.

[0036] According to the starting position of the detection region, the position of the motion platform is measured by reading the data of the grating ruler through the reading head. The jitter detection is started when the motion platform moves to the starting position. According to the starting position and the set length of the jitter precision detection region, the first jitter precision region DA11 The actual number of clock pulses N A11 The actual number of clock pulses N in the jitter accuracy region A11 The count is compared with the ideal clock pulse count N0. If the difference between the two is within a specified difference threshold range, the count is 0; if the difference exceeds the specified difference threshold range, the count is 1. The count of 0 or 1 is the first detection value. The difference is taken as the absolute value, and the difference threshold is a positive number; or the difference can be positive or negative, and the difference threshold is a range. As the motion platform moves, it enters the second jitter accuracy detection area D. A12 D is obtained through clock pulses A12 The actual number of clock pulses N in the jitter accuracy region A12 , and the jitter accuracy detection area D A11 Similarly, it is compared with the ideal clock pulse count N0. If the difference between the two is within the specified difference threshold range, then it is compared with the jitter accuracy detection area D. A11 If the counts are the same, and the difference between the two exceeds the specified difference threshold, then in the jitter accuracy detection area D... A11 Add 1 to the count. The motion platform moves at a constant speed to the third jitter accuracy detection area D. A13 D is obtained through clock pulses A13 The actual number of clock pulses N in the jitter accuracy region A13 The actual number of clock pulses N A13 Compare the result with the ideal clock pulse count N0. If the difference between the two is within the specified difference threshold range, then compare it with the jitter accuracy detection area D. A12 If the counts are the same, and the difference between the two exceeds the specified difference threshold, then in the jitter accuracy detection area D... A12 The count is incremented by 1. The remaining jitter accuracy range is then checked sequentially until the jitter accuracy range D is reached. A1j jitter accuracy area D A1j The actual clock pulse N A1j Compare the result with the ideal clock pulse count N0. If the difference between the two is within the specified difference threshold range, then compare it with the jitter accuracy detection area D. A1（j-1） If the counts are the same, and the difference between the two exceeds the specified difference threshold, then in the jitter accuracy detection area D... A1（j-1） Add 1 to the count to obtain the count K1 of sub-region A1, which is the second count.

[0037] Next, sub-region A2 is detected, and the process is the same as for sub-region A1, starting from the first jitter accuracy region D of sub-region A2. A21 Start detection and obtain the first jitter accuracy region D in sub-region A2. A21 The actual number of clock pulses NA21 The actual number of clock pulses N in the jitter accuracy region A21 The value is compared with the ideal clock pulse count N0. If the difference is within the specified difference threshold range, the count is K1; if the difference exceeds the specified difference threshold range, the count is K1+1. The second jitter accuracy region D in sub-region A2 is then obtained. A22 The actual number of clock pulses N A22 The actual number of clock pulses N in the jitter accuracy region A22 The value is compared with the ideal clock pulse count N0. If the difference between the two is within the specified difference threshold range, then it is compared with the jitter accuracy detection area D. A21 If the counts are the same, and the difference between the two exceeds the specified difference threshold, then in the jitter accuracy detection area D... A21 The count is incremented by 1. This process is repeated for all jitter accuracy areas in sub-region A2, with the last jitter accuracy area D in sub-region A2 being counted. A2j The final count is obtained by counting K2 in subregion A2.

[0038] Continue detecting sub-regions A3 to Am to obtain counts K3 to Km for sub-regions A3 to Am. Among K1, K2, K3...Km, find the number of different numbers. This number of different numbers is the third detection value. For example, if K1=5, K2=7, K3=7, K4=10, K5=10, K6 to K10 are all 14, and K11 to Km are all 17, then the number of different values ​​among the M counts obtained from the M sub-regions in the detection area is 5. Compare this number of different values ​​(5) with a set jitter threshold. If it is greater than the jitter threshold, it is determined to be jitter; if it is less than the jitter threshold, it is determined to be normal.

[0039] As mentioned earlier, the actual number N of clock pulses in the jitter accuracy region is determined. Ai1 Another method to determine whether the actual clock pulse count N exceeds a threshold range is to directly add or subtract the absolute value of the difference threshold from the ideal clock pulse count to obtain the clock pulse count threshold. This clock pulse count threshold is the range between the absolute values ​​of the ideal clock pulse count plus or minus the difference threshold, used to determine the actual clock pulse count N. Ai1 Is it within the threshold range for the number of clock pulses? If the actual number of clock pulses N Ai1 If the count is within the threshold range for the number of clock pulses, the count is incremented by 0. If the actual number of clock pulses N... Ai1 If the count exceeds the threshold for the number of clock pulses, the count is incremented by 1.

[0040] Corresponding to the above method of detecting jitter by counting, the jitter detection system of the motion platform comprises a main control unit and a jitter detection unit, the jitter detection unit comprises a sub-control unit, a clock device, a comparator, a counter and a register. The main control unit communicates with the sub-control unit, the comparator and the register, the sub-control unit obtains information of the clock device and the reading head, controls the comparator, the register and the counter. The comparator receives information of the main control unit and the sub-control unit, the counter receives information of the comparator, and the register receives information of the counter.

[0041] The main control unit is used for setting the motion speed of the motion platform, the number and / or length of the sub-regions in the detection region, the number and / or length of the jitter precision regions, the jitter precision threshold and the jitter threshold, dividing the detection region into sub-regions and jitter precision detection regions, and obtaining the ideal clock pulse number N0 according to the clock pulse frequency F of the clock device, the speed V of the ideal motion platform and the length d of the jitter precision detection region, and determining whether to jitter according to the feedback result.

[0042] The sub-control unit is used for receiving instructions of the main control unit, sequentially reading the actual clock pulse number of each jitter precision region according to the instructions of the main control unit, and outputting the clock pulse number to the comparator according to the jitter precision threshold.

[0043] The clock device is used for outputting stable clock pulses.

[0044] The comparator is used for receiving the jitter precision threshold output by the main control unit and the clock pulse number output by the sub-control unit.

[0045] The counter is used for recording the number of jitter precision detection regions exceeding the threshold.

[0046] The register is used for storing the cumulative count corresponding to the sub-region, and the number of registers corresponds to the number of sub-regions divided in the detection region. Each register stores the cumulative count of the corresponding sub-region.

[0047] The jitter precision threshold is a difference threshold or a clock pulse number threshold obtained based on the ideal clock pulse number and the difference threshold. When the jitter precision threshold is a difference threshold, the main control unit outputs the difference threshold to the comparator and outputs the ideal clock pulse number to the sub-control unit. The sub-control unit obtains the difference between the actual clock number and the ideal clock pulse number and outputs the difference clock pulse number to the comparator. When the jitter precision threshold is a clock pulse number threshold, the main control unit outputs the clock pulse number threshold to the comparator, and the sub-control unit outputs the actual clock pulse number to the comparator after obtaining the actual clock pulse number.

[0048] According to the above detection method, the jitter precision threshold is taken as an example to illustrate the number of clock pulses.

[0049] The main control unit sets the motion speed of the motion platform, the detection area, the number and / or length of the sub-areas, the number and / or length of the jitter precision areas, the jitter precision threshold and the jitter threshold, divides the detection area into a plurality of sub-areas, divides the sub-areas into a plurality of jitter precision detection areas, and obtains the ideal number of clock pulses N0 according to the clock pulse frequency F of the clock, the speed V of the ideal motion platform and the length d of the jitter precision detection area.

[0050] The secondary control unit receives the instructions of the main control unit and the data of the reading head, reads the position of the motion platform through the reading head according to the jitter precision areas and sub-areas divided by the main control unit, obtains the actual number of clock pulses output by the clock when the motion platform passes through the jitter precision area, and outputs the difference between the actual number of clock pulses and the ideal number of clock pulses or directly outputs the actual number of clock pulses to the comparator.

[0051] The comparator receives the actual number of clock pulses output by the secondary control unit and the jitter precision threshold received from the main control unit, and outputs the comparison result. If the actual number of clock pulses is within the jitter precision threshold range, 0 is output, and if the actual number of clock pulses exceeds the jitter precision threshold range, 1 is output.

[0052] The counter counts according to the output information received from the comparator. When the actual number of clock pulses exceeds the jitter precision threshold range, the counter is incremented by 1. After completing the detection of all jitter precision areas in a sub-area, the counter outputs data to the register corresponding to the current sub-area.

[0053] After completing the detection of all sub-areas, the main control unit reads the cumulative counts of each sub-area stored in each register, analyzes the number of different values in all stored cumulative counts, compares the number of different values in the cumulative counts with the jitter threshold, and determines that it is normal if the number of different values is not greater than the jitter threshold, and determines that it is jitter if the number of different values is greater than the jitter threshold.

[0054] The jitter detection unit can also only include a clock, a comparator, a counter and a register. The main control unit directly obtains the information of the clock and the reading head, and controls the comparator, the register and the counter.

[0055] As Figures 7-8As shown, the second implementation method will be described in detail below. Similar to the first embodiment, the detection area is divided into M sub-regions, namely sub-region A1, sub-region A2, sub-region A3...sub-region Am, each sub-region having a length of a. Each sub-region is then sequentially divided into J jitter accuracy regions, namely jitter accuracy regions D... Ai1 Jitter accuracy area D Ai2 Jitter accuracy area D Ai3 ...Jitter precision area D Aij Where i is the number of the sub-region corresponding to the jitter accuracy region, and the length of each jitter accuracy detection region is d. The frequency of the clock pulse used to detect the actual number of clock pulses when the motion platform moves at a constant speed is F. As mentioned above, the ideal number of clock pulses N0 = F × d / V for the jitter detection region is obtained based on the set speed V of the motion platform moving at a constant speed, the determined frequency F of the clock pulse, and the length d of the jitter accuracy detection region.

[0056] Based on the determined starting position of the detection area, the position of the motion platform is measured by reading data from the grating ruler using the reading head. Once the motion platform has moved to the starting position, vibration detection begins. Based on the starting position and the length of the set vibration accuracy detection area, the first vibration accuracy area D in sub-region A1 is obtained. A11 The actual number of clock pulses N A11 As the motion platform moves, it enters the second jitter accuracy detection area D. A12 , obtain D A12 The actual number of clock pulses N in the jitter accuracy region A12 , and the jitter accuracy detection area D A11 The actual number of clock pulses N A11 The values ​​are compared, and the number of actual clock pulses with the smaller value is retained. The motion platform moves at a constant speed to the third jitter accuracy detection area D. A13 D is obtained through clock pulses A13 The actual number of clock pulses N in the jitter accuracy region A13 , with a smaller value N A11 Or N A12 Similarly, the number of actual clock pulses with smaller values ​​is retained. The remaining jitter accuracy range is then checked sequentially, up to jitter accuracy range D. A1j jitter accuracy area D A1j The actual clock pulse N A1j By comparing the smaller number of actual clock pulses left in the previous (j-1) jitter accuracy detection areas, the smallest number of actual clock pulses N1 in all jitter accuracy detection areas in sub-region A1 is obtained.

[0057] Then the sub-region A2 is detected, and the first jitter accuracy region D in the sub-region A2 is detected in the same way as the sub-region A1 A21 The detection is started, and the actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained A21 The detection is continued, and the actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained A21 The actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained A22 The actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained A22 The actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained A22 The actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained A21 The actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained A21 The actual clock pulse number N of the first jitter accuracy region D in the sub-region A2 is obtained

[0058] The detection is continued on the sub-region A3 to the sub-region Am, and the minimum actual clock pulse number N3 to Nm of the sub-region A3 to the sub-region Am is obtained. According to the calculation formula Vn=Fxd / Nn, the maximum speed value corresponding to each sub-region is obtained, and it is judged whether the maximum speed value of all sub-regions in the detection interval is within the allowed jitter threshold range. If it is within the jitter threshold range, it is determined to be normal, and if it is not within the jitter threshold range, it is determined to be jitter. Or according to the required speed jitter threshold, the jitter threshold of the corresponding clock pulse number is calculated, and according to the obtained minimum actual clock pulse number N1 to Nm, it is judged whether it is within the clock pulse number fluctuation range, and it is determined whether it is jitter. In addition to obtaining the minimum actual clock pulse number of each sub-region, the maximum actual clock pulse number of each sub-region can also be obtained, which is opposite to the way of obtaining the minimum actual clock pulse number. When comparing, the larger actual clock pulse number is obtained.

[0059] Corresponding to the above method of detecting jitter by obtaining the maximum or minimum clock pulse number, which is different from the foregoing embodiment, the jitter detection unit includes a secondary control unit, a clock device, a comparator, and a register. The main control unit communicates with the secondary control unit, the comparator, and the register, the secondary control unit obtains information of the clock device and the reading head, and controls the comparator and the register. The comparator receives information of the main control unit and the secondary control unit, and the register receives information of the comparator.

[0060] The main control unit is configured to set the motion speed of the motion platform, the number and / or length of the sub-regions of the detection region, the number and / or length of the jitter accuracy regions, and the jitter threshold, divide the detection region into sub-regions and jitter accuracy detection regions, and obtain the ideal clock pulse number N0 according to the clock pulse frequency F of the clock device, the ideal motion speed V of the motion platform, and the length d of the jitter accuracy detection region.

[0061] The secondary control unit is configured to receive the instructions of the main control unit, read the actual clock pulse number of each jitter accuracy region according to the instructions of the main control unit, and output the actual clock pulse number of the jitter accuracy region to the comparator.

[0062] The clock device is configured to output stable clock pulses.

[0063] The comparator is configured to receive the actual clock pulse number output by the secondary control unit and compare the actual clock pulse number with the previously stored clock pulse number.

[0064] The register is configured to store the minimum clock pulse number corresponding to the sub-region, and the number of registers corresponds to the number of sub-regions of the detection region, and each register stores the minimum clock pulse number corresponding to the sub-region.

[0065] According to the above detection method, the main control unit sets the motion speed of the motion platform, the detection region, the number and / or length of the sub-regions, the number and / or length of the jitter accuracy regions, and the jitter threshold, divides the detection region into a plurality of sub-regions, divides the sub-regions into a plurality of jitter accuracy detection regions, and obtains the ideal clock pulse number N0 according to the clock pulse frequency F of the clock device, the ideal motion speed V of the motion platform, and the length d of the jitter accuracy detection region.

[0066] The secondary control unit receives the instructions of the main control unit and the data of the read head, reads the position of the motion platform through the read head according to the jitter accuracy regions and sub-regions divided by the main control unit, obtains the actual clock pulse number output by the clock device when the motion platform passes through the jitter accuracy region, and outputs the actual clock number to the comparator.

[0067] The comparator receives the actual clock pulse number output by the secondary control unit, compares the actual clock pulse number with the smaller actual clock pulse number stored in the comparator, and stores the smaller actual clock pulse number. After completing the detection of all the jitter accuracy regions of a sub-region, the comparator outputs the smallest actual clock pulse number in the sub-region to the register corresponding to the current sub-region.

[0068] After detecting all sub-areas, the main control unit reads the minimum actual clock pulse number of each sub-area stored in each register, judges whether it meets the jitter threshold, and if it meets the judgment, it is normal, and if it does not meet the judgment, it is jitter.

[0069] Similarly, the jitter detection unit can also only include a clock, a comparator, a counter and a register, and the main control unit directly obtains the information of the clock and the reading head, and controls the comparator, the register and the counter.

[0070] As shown in Figure 9 The jitter detection method and the jitter detection system are applied to a direct writing exposure system, which comprises a motion platform, a main control system, a synchronization board and a spatial light modulator control board (DGB). The main control system controls the motion platform, the synchronization board and the spatial light modulator control board (DGB). The main control system comprises the main control unit of the jitter detection system, and the jitter detection unit of the jitter detection system is arranged on the synchronization board. During the movement of the motion platform, the jitter information of the motion platform is rapidly obtained in real time, and the motion platform is corrected in time to avoid the rejection of the workpiece.

Claims

1. A method for detecting the jitter of a motion platform, the motion platform comprising a grating ruler and a reading head, characterized in that... Using the uniform motion area of ​​the motion platform as the jitter detection area, the jitter detection area is divided into multiple sub-regions, each with the same length. Each sub-region is further divided into multiple jitter precision detection areas, each with the same length. A stable clock pulse is used to detect the actual clock pulse information corresponding to the grating ruler position information read by the reading head in each jitter precision detection area. Based on the actual clock pulse information of each jitter precision detection area, a first detection value of the jitter precision detection area is obtained. Based on the first detection value of the jitter precision detection area, a second detection value of the corresponding sub-region is obtained. The second detection values ​​of the sub-regions are integrated to obtain a third detection value of the jitter detection area. The third detection value is compared with a jitter threshold to determine whether the motion platform is jittering. The first detection value is determined by comparing the actual clock pulse information with the ideal clock pulse information to see if it exceeds a threshold range. If it exceeds the threshold range, the count is 1; if it does not exceed the threshold range, the count is 0. The second detection value is the cumulative value of the first detection values ​​in the current sub-region and all sub-regions before the current sub-region. The third detection value is the number of different values ​​in the second detection value. Alternatively, the first detection value is obtained by comparing the actual clock pulse information with the smaller or larger clock pulse information already obtained in the sub-region, and the first detection value is the actual clock pulse information with the smaller or larger value of the two; the second detection value is the minimum or maximum clock pulse information obtained in each sub-region; the third detection value is the speed range value or clock information range value obtained based on all the second detection values. The ideal clock pulse information is obtained according to the formula N0=F×d / V, where N0 is the number of ideal clock pulses, F is the frequency of the clock pulses, V is the ideal speed of the motion platform, and d is the length of the jitter accuracy detection area.

2. The jitter detection method according to claim 1, characterized in that: The actual clock pulse information is the number or duration of clock pulses corresponding to the jitter accuracy detection area.

3. A jitter detection system applied to the jitter detection method according to any one of claims 1-2, characterized in that: It includes a main control unit and a jitter detection unit. The jitter detection unit includes a clock, a jitter accuracy region calculation unit, and a sub-region data storage unit. The main control unit controls the jitter detection unit and is used to set the parameters of the motion platform, detection area, sub-region, jitter detection area, and jitter threshold. It also obtains a third detection value based on the second detection value output by the jitter detection unit for judgment. The clock is used to output a stable clock pulse. The jitter accuracy region calculation unit is used to sequentially obtain the first detection value of the jitter accuracy region and obtain the second detection value in units of sub-regions. The sub-region data storage unit is used to store the second detection value respectively.

4. The jitter detection system according to claim 3, characterized in that: The jitter accuracy region calculation unit includes a comparator and a counter, and the counter counts the result of the comparator.

5. The jitter detection system according to claim 3, characterized in that: The jitter accuracy region calculation unit includes a comparator, which is used to compare the acquired actual clock pulse information with the smaller clock pulse information already acquired in the sub-region to obtain a first detection value.

6. A direct-write exposure system using the jitter detection system of any one of claims 3-5, characterized in that: The direct-write exposure system includes a motion platform, a main control system, a synchronization board, and a spatial light modulator control board. The main control system controls the motion platform, the synchronization board, and the spatial light modulator control board. The main control system includes the main control unit of the jitter detection system, and the jitter detection unit of the jitter detection system is disposed on the synchronization board.

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