Circuit etching method and device for thermal printing sheet

Abstract

The invention relates to the technical field of image processing, in particular to a line etching method and device for a thermal printing sheet, and the method comprises the steps: obtaining each structural region in an exposure image of the thermal printing sheet, carrying out the equal division of all pixel values in each structural region, and analyzing the pixel order change degree and the pixel value difference in the region, acquiring the pixel disorder degree of each structural area; the method comprises the following steps of: obtaining a plurality of structural areas, obtaining the angular point distribution difference degree of each structural area by utilizing the angular point characteristics in each structural area, taking the corresponding structural areas with the same angular point distribution difference degree as the same structural area of each structure, and further obtaining the search step length of the same structural area of each structure so as to carry out line etching on the thermal printing sheet. The circuit etching efficiency of the thermal printing sheet can be improved.

Description

Technical Field

[0001] This application relates to the field of image processing technology, specifically to a method and apparatus for etching lines on a thermal printing sheet. Background Technology

[0002] Thermal paper printing technology uses miniature heating elements within the printing sheet to transfer heat to designated areas of the thermal paper. This heat causes a chemical reaction between the leuco dye and the developer in the thermal paper, resulting in color. Therefore, the accuracy of the circuitry within the thermal printing sheet determines the performance of the thermal print. The heating element in thermal printing is a thin-film resistor, typically made of tantalum compounds or mixtures, and is fabricated through an exposure etching process.

[0003] For etching circuitry on thermal printed circuit boards, the resistive coating is typically etched using an exposure method. After etching, the exposure effect needs to be checked to ensure the continuity of subsequent circuitry. During the etching process, the image is enhanced, and the etching effect is determined based on the differences in pixels within the etched area. Traditional methods generally use Non-Local Means (NLM) filtering algorithms for noise reduction. However, due to the piecewise similarity of the circuit structure on thermal printed circuit boards, traditional NLM algorithms, when using a fixed search step size, are prone to generating unnecessary searches, thus increasing the computational load and detection time. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this application is to provide a method and apparatus for etching lines on a thermally printed wafer. The specific technical solution adopted is as follows: This application provides a method for etching lines on a thermal printing wafer, including the following steps: Obtain each structural region in the exposed image of the thermal print; By dividing all pixel values ​​in each structural region into equal parts, a symbol set for each structural region is obtained. The pixel values ​​in the symbol set of each structural region are arranged in ascending order. The pixel order variation of each structural region is obtained by using the difference sequence of the arranged sequence. Then, the pixel disorder of each structural region is obtained by combining the differences of all pixel values ​​in the symbol set of each structural region. By analyzing the differences between all corner points and the center point in each structural region, the corner point distribution difference of each structural region can be obtained. Structural regions with similar corner point distribution differences are designated as the same structural region for each type of structure. The degree of difference between any two corner points within the same structural region is statistically analyzed to obtain the structural distribution distance of each same structural region. This allows us to obtain the search step size for the same structural region for each type of structure, which is then used to etch lines onto the thermal printout.

[0005] Preferably, the method for obtaining each structural region of the thermal printing sheet is as follows: The exposed image captured by the camera is converted into a grayscale image to obtain the exposed image of the thermal printing sheet; Edge detection is performed on the exposed image of the thermal print sheet, and non-edge pixels in the edge image are merged to obtain multiple non-edge regions. These non-edge regions are used as masks to obtain each structural region in the exposed image of the thermal print sheet.

[0006] Preferably, the method for obtaining the symbol set of each structural region includes: All pixel values ​​in each structural region are divided into quartiles, and the pixel values ​​between the lower quartile and the upper quartile are used to form a symbol set for each structural region.

[0007] Preferably, the pixel level variation of each structural region is the mean of all elements in the difference sequence of each structural region.

[0008] Preferably, the pixel disorder of each structural region is positively correlated with the range of all pixel values ​​in the symbol set of each structural region and the pixel order variation of each structural region.

[0009] Preferably, the method for obtaining the center point is as follows: corner point detection is performed on each structural region, and the average value of the corner point pixel positions in each structural region is taken as the center point of each structural region.

[0010] Preferably, the method for calculating the corner point distribution difference of each structural region is as follows: ; In the formula, The corner point distribution difference of the i-th structural region; Let be the number of all corner points in the i-th structural region; The mean of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; Let V be the variance of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; This is a preset constant.

[0011] Preferably, the method for obtaining the structural distribution distance of each homogeneous structural region is as follows: The Euclidean distance between any two corner points in the same structural region is calculated, and the square root of the sum of the squares of the maximum and minimum Euclidean distances is taken to obtain the structural distribution distance of each same structural region.

[0012] Preferably, the method for calculating the search step size of the same structural region for each structure is as follows: ; In the formula, Let be the search step size for the same structural region of the j-th structure; The mean pixel disorder of all structural regions in the same structural region of the j-th structure; The mean of the structural distribution distances of all structural regions within the same structural region of the j-th structure; It represents the maximum Euclidean distance between any two corner points in all structural regions; To find the summation normalization function; This is the rounding function.

[0013] This application embodiment also provides a circuit etching apparatus for thermal printed wafers, wherein the apparatus stores a computer program, and when the computer program is executed by a processor, it implements the steps of the circuit etching method for thermal printed wafers described in any of the above embodiments.

[0014] As can be seen from the above, the method and apparatus for etching lines on a thermal printing sheet provided in this application have at least the following beneficial effects: This application fully considers that during the etching of circuits on thermal printed wafers, traditional filtering methods for noise reduction, due to their fixed search step size, are prone to generating unnecessary searches. Therefore, an edge detection algorithm is used to divide the exposed image into structural regions, and the corner distribution difference of the structural regions is calculated based on the corner distribution status of the structural regions. This distinguishes the same structural regions in the exposed image of the thermal printed wafer, thereby processing the exposed image and helping to enhance the image, improve image clarity, and reduce noise in the image.

[0015] Furthermore, by utilizing the shape distribution of regions with similar structures, the search efficiency of the NLM algorithm can be improved, the search volume reduced, and the denoising time of the exposed image shortened, thereby reducing the time consumed in the exposure process of the thermal printed wafer. By improving the search step size of the NLM algorithm, the exposed image of the thermal printed wafer can be enhanced, enabling rapid identification and processing of noise in the exposed image. The enhanced image not only has higher clarity but also more accurately identifies defects and residual areas in the circuitry, thus achieving rapid secondary exposure of residual plating areas, shortening both exposure and etching times, and improving the efficiency of circuit etching on the thermal printed wafer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart illustrating the steps of a method for etching lines on a thermal printing sheet provided in this application. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a thermal printing wafer etching method and apparatus proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise specified and limited, terms such as “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the article or device that includes said element. Furthermore, the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0020] The following description, in conjunction with the accompanying drawings, details a specific scheme for a thermal printing plate line etching method and equipment provided in this application.

[0021] Please see Figure 1 It illustrates a flowchart of a method for etching lines on a thermally printed wafer according to an embodiment of this application, including the following steps: Step 1: Obtain each structural region in the exposure image of the thermal print.

[0022] The circuit structure of the thermal printing sheet includes wires, a heat storage layer, resistors, and voltage divider resistors. The wires transmit heating electrical signals to the heating element, activating it to heat up. The heat storage layer evenly distributes heat to the surface of the thermal paper. The resistors convert electrical energy into heat energy. The voltage divider resistors ensure that the generated heat is quickly dissipated by the ceramic substrate, preventing the formation of a heated image on the printing paper and solving the problem of complex high-resistivity thin-film processing.

[0023] For thermal printed wafers with pre-deposited resistive films, during exposure etching, the exposure unit uses a built-in positioning algorithm to determine the exposure area and performs exposure to remove the coating to be etched. Simultaneously, the image captured by a high-precision CCD camera after exposure is converted to a grayscale image using a weighted average method, yielding the exposure image of the thermal printed wafer.

[0024] Since each region in the coated thermal PCB has a different function, the circuit structures are not connected, and there are obvious layers between different structures, the Canny edge detection algorithm is used to detect edges in the exposed image of the thermal PCB to obtain the edge image of the exposed image. Non-edge pixels in the edge image are then merged to obtain multiple non-edge regions. These non-edge regions are then used as masks to extract their corresponding regions in the exposed image, which are used as each structural region in the exposed image of the thermal PCB to characterize each functional region in the thermal PCB. Preferably, in this embodiment, the weighted average method and the Canny edge detection algorithm are both well-known techniques, and the specific process will not be described in detail.

[0025] Step 2: By dividing all pixel values ​​in each structural region into equal parts, a symbol set for each structural region is obtained. The pixel values ​​in the symbol set of each structural region are arranged in ascending order. The pixel order variation of each structural region is obtained by using the difference sequence of the arranged sequence. Then, the pixel disorder of each structural region is obtained by combining the differences of all pixel values ​​in the symbol set of each structural region.

[0026] For each structural region of the thermal printout, structures of the same functional type exhibit similarities and homogeneity, while distinct boundaries exist between different structures. After exposure, no plating should remain within the voltage divider resistor area to ensure the accuracy of the voltage divider resistor after etching, thereby guaranteeing the stability of the entire circuit performance. Since the functionality of each location within each structural region is identical, and each region is manufactured using the same material, the pixels at each location within each structural region should be identical. However, due to noise, the pixel values ​​of pixels within a region can vary, causing the pixel values ​​to become less identical. Furthermore, noise points can lead to pixel values ​​that are too large or too small, deviating from the overall pixel value level.

[0027] Therefore, all pixel values ​​in each structural region are divided into quartiles, and the pixel values ​​between the lower and upper quartiles are used to form a symbol set for each structural region to represent the overall pixel distribution of the corresponding structural region, thereby removing the influence of noise.

[0028] Furthermore, the pixel values ​​of different values ​​in the symbol set of each structural region are arranged in ascending order, and the arranged sequence is subjected to first-order difference calculation to obtain the difference sequence of each structural region. Then, the mean of all elements in the difference sequence of each structural region is used as the pixel order variation of each structural region. Preferably, in this embodiment, the calculation of quartiles and the first-order difference algorithm are well-known techniques, and the specific process will not be described in detail.

[0029] Based on the above analysis, and considering the differences in pixel values ​​within the symbol set of each structural region, combined with the pixel order variation of each structural region, the pixel disorder degree of each structural region is calculated. In this embodiment, the specific calculation formula is as follows: ; In the formula, Let be the pixel disorder degree of the i-th structural region; Let be the range of all pixel values ​​in the symbol set of the i-th structural region; Let be the pixel level variation of the i-th structural region.

[0030] in, This represents the overall pixel difference variation in each structural region; This indicates the degree of gradient difference in pixel value changes within each structural region. The smaller the difference in pixel values ​​within a structural region, the smaller the difference in surface material within that region, resulting in better exposure and a smaller pixel gradient value, which in turn reduces pixel disorder. A lower pixel disorder value leads to better etching results, ensuring the functionality of the thermal printing pad's circuitry, allowing for more efficient heat dissipation during printing, and ultimately, better printing quality.

[0031] Step 3: Obtain the corner point distribution difference degree of each structural region by measuring the differences between all corner points and the center point in each structural region.

[0032] Because the same manufacturing materials and processes are used in structural regions with the same function, the distribution of structural regions with the same function on the thermal printing sheet is consistent, resulting in the same pixel value distribution under normal conditions, and consequently, the same pixel disorder in the structural regions.

[0033] Furthermore, each structural region strives for smoothness, meaning that the distribution of pixels in each structural region is similar, which may result in similar or identical pixel disorder levels among different structural regions. However, due to the different functions of different structural regions, their shapes and sizes vary, leading to significant structural differences between them. Meanwhile, within the same type of structure, the structural state is also the same due to the repetition of circuits.

[0034] Therefore, the Harris corner detection algorithm is used to detect corners in each structural region, obtaining all corners of each structural region. The mean value of the pixel positions of all corners in each structural region is calculated, and the pixel position corresponding to the mean value is used as the center point of each structural region. Then, the mean Euclidean distance between all corners and their corresponding center points in each structural region is calculated to represent the distribution length of each structural region. The variance of the Euclidean distance between all corners and their corresponding center points in each structural region is calculated to represent the distribution uniformity of each structural region. Preferably, in this embodiment, the Harris corner detection algorithm is a known technique, and the specific process will not be described in detail.

[0035] Based on the above analysis, the number of all corner points in each structural region is counted. Combined with the average level and fluctuation of the distance between all corner points and their corresponding center points in each structural region, the corner point distribution difference in each structural region is calculated. In this embodiment, the specific calculation formula is as follows: ; In the formula, The corner point distribution difference of the i-th structural region; Let be the number of all corner points in the i-th structural region; The mean of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; Let V be the variance of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; This is a preset constant. However, because the circuitry in the thermal printout may have symmetrical structures such as squares, the variance of the distance between all corner points and their corresponding center points in the symmetrical structure region may be 0, resulting in zero variability in the corner point distribution. To avoid this situation, The value range is [1, 10], and it is set to 1 in this embodiment.

[0036] The more complex the structure of the circuitry in a thermal printout, the more complex its shape, the more corner points are formed in the corresponding structural regions, the more uneven the distribution of corner point positions, and the greater the distance from the corner point to the center point. At the same time, the variance of the distances from all corner points to the center point will also be greater. Therefore, the difference in the distribution of corner points in the structural regions is greater, making the feature distinction between different structural regions obvious and facilitating the identification of each structural region.

[0037] Step 4: Select structural regions with the same degree of difference in corner point distribution as the same structural region for each type of structure, and count the degree of difference between any two corner points in the same structural region to obtain the structural distribution distance of each same structural region, so as to obtain the search step size of the same structural region for each type of structure, and then perform circuit etching on the thermal printed sheet.

[0038] Furthermore, since regions of the same type are structurally similar, the difference in corner point distribution between two regions is the same. Therefore, regions with the same value of difference in corner point distribution are denoted as regions of the same type, and multiple regions of the same type are obtained. For each type of region of the same type, the Euclidean distance between any two corner points in the region of the same type is calculated to characterize the difference in structural distance in each region. The square root of the sum of the squares of the maximum and minimum Euclidean distances is then calculated to obtain the structural distribution distance of each region of the same type, which is used to characterize the distribution difference in each region of the same type.

[0039] Based on the above analysis, and considering the average level of structural distribution distance among all structural regions of the same type for each structure, combined with the average level of pixel disorder among all structural regions of the same type for each structure, the search step size for the same structural region of each structure is calculated. In this embodiment, the specific calculation formula is as follows: ; In the formula, Let be the search step size for the same structural region of the j-th structure; The mean pixel disorder of all structural regions in the same structural region of the j-th structure; The mean of the structural distribution distances of all structural regions within the same structural region of the j-th structure; It represents the maximum Euclidean distance between any two corner points in all structural regions; To find the summation normalization function; This is the rounding function.

[0040] Specifically, the larger the structural shape of a region, the more likely the pixel distribution within that region is to be chaotic, and the greater the distance between the structural distributions. Therefore, using a longer step size can effectively find similar pixels in the exposed image, improving image denoising efficiency, thereby enhancing the image quality of the thermal printing plate circuitry, better identifying the exposure effect of the resistive regions in the circuitry, ensuring the functionality of the thermal printing plate circuitry, and improving printer efficiency.

[0041] Therefore, the exposed image and the search step size of all structural regions within the exposed image are used as input to the NLM algorithm, and the output is an enhanced image of the exposed image. By identifying the differences between similar structural regions in the enhanced image, such as pixel value differences between similar structural regions, areas with incomplete exposure and residual coating can be identified. Based on the location of these structural regions, the thermal print sheet is then subjected to a second exposure. Further, the second-exposed thermal print sheet is etched using an etching machine with etching solution, and then acid-washed, thus realizing a method for etching circuits on a thermal print sheet. The NLM algorithm is a well-known technique, and its specific process will not be elaborated further.

[0042] Based on the same inventive concept as the above method, this application embodiment also provides a circuit etching apparatus for thermal printed sheets, wherein the apparatus stores a computer program, and when the computer program is executed by a processor, it implements the steps of any of the above-described circuit etching methods for thermal printed sheets.

[0043] In addition, a circuit etching device for thermal printed wafers includes a data acquisition unit, an exposure machine, a residue detector, an etching machine, and an acid pickling machine. The data acquisition unit is used to collect data during the exposure and etching process of the thermal printed wafer; the exposure machine is used to expose the thermal printed wafer; the residue detector is used to detect the plating residue in the exposed areas of the thermal printed wafer; the etching machine is used to etch the exposed areas of the thermal printed wafer; and the acid pickling machine is used to clean the etching solution.

[0044] It is understood that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0045] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0046] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the protection scope of this application.

Claims

1. A method for etching lines on a thermal printing sheet, characterized in that, Includes the following steps: Obtain each structural region in the exposed image of the thermal print; By dividing all pixel values ​​in each structural region into equal parts, a symbol set for each structural region is obtained. The pixel values ​​in the symbol set of each structural region are arranged in ascending order. The pixel order variation of each structural region is obtained by using the difference sequence of the arranged sequence. Then, the pixel disorder of each structural region is obtained by combining the differences of all pixel values ​​in the symbol set of each structural region. By analyzing the differences between all corner points and the center point in each structural region, the corner point distribution difference of each structural region can be obtained. Structural regions with similar corner point distribution differences are designated as the same structural region for each type of structure. The degree of difference between any two corner points within the same structural region is statistically analyzed to obtain the structural distribution distance of each same structural region. This allows us to obtain the search step size for the same structural region for each type of structure, which is then used to etch lines onto the thermal printout.

2. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining each structural region of the thermal printing sheet is as follows: The exposed image captured by the camera is converted into a grayscale image to obtain the exposed image of the thermal printing sheet; Edge detection is performed on the exposed image of the thermal print sheet, and non-edge pixels in the edge image are merged to obtain multiple non-edge regions. These non-edge regions are used as masks to obtain each structural region in the exposed image of the thermal print sheet.

3. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining the symbol set of each structural region includes: All pixel values ​​in each structural region are divided into quartiles, and the pixel values ​​between the lower quartile and the upper quartile are used to form a symbol set for each structural region.

4. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The pixel-level variation of each structural region is the mean of all elements in the difference sequence of each structural region.

5. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The pixel disorder of each structural region is positively correlated with the range of all pixel values ​​in the symbol set of each structural region and the pixel order variation of each structural region.

6. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining the center point is as follows: corner point detection is performed on each structural region, and the average value of the pixel positions of all corner points in each structural region is taken as the center point of each structural region.

7. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for calculating the corner point distribution difference of each structural region is as follows: ； In the formula, The corner point distribution difference of the i-th structural region; Let be the number of all corner points in the i-th structural region; The mean of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; Let V be the variance of the Euclidean distances between all corner points and their corresponding center points in the i-th structural region; This is a preset constant.

8. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for obtaining the structural distribution distance of each region with the same structural type is as follows: The Euclidean distance between any two corner points in the same structural region is calculated, and the square root of the sum of the squares of the maximum and minimum Euclidean distances is taken to obtain the structural distribution distance of each same structural region.

9. The method for etching lines on a thermally printed wafer as described in claim 1, characterized in that, The method for calculating the search step size of the same structural region for each type of structure is as follows: ； In the formula, Let be the search step size for the same structural region of the j-th structure; The mean pixel disorder of all structural regions in the same structural region of the j-th structure; The mean of the structural distribution distances of all structural regions within the same structural region of the j-th structure; It represents the maximum Euclidean distance between any two corner points in all structural regions; To find the summation normalization function; This is the rounding function.

10. A circuit etching apparatus for thermally printed wafers, the apparatus storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the line etching method for a thermal printed sheet as described in any one of claims 1-9.

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