JPH0550028B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a printed wiring board having a conductor circuit composed of lines and lands, and a pattern film required for manufacturing this printed wiring board. For creating the original pattern film
This relates to a method for deleting unnecessary lands from CAD data.

(Prior Art) In order to form a necessary conductor circuit on a printed wiring board, no matter what method is used, there must be a source for the conductor circuit. Usually, a material corresponding to the conductive circuit, that is, a pattern film on which a pattern is drawn, is used as the source of the conductive circuit. To create this pattern film, it is necessary to create a pattern design drawing, which is the basis of the pattern film, from a given circuit diagram. In other words, in order to form the conductor circuits necessary for printed wiring boards,
First, it is necessary to create a pattern design drawing from the circuit diagram, and then create a pattern film from this pattern design drawing.By using this pattern film, it is finally possible to create the necessary conductor circuits on the printed wiring board. It can be formed.

Generally, the following method is generally adopted as a method for creating printed wiring board pattern film data. First, an operator creates a pattern design drawing from a given circuit diagram while considering the placement of parts and the layout of the pattern. After checking and correcting this pattern design drawing, data for creating a pattern film is created using a CAD system (a system that includes a digitizer), and this pattern film is created.

A more specific explanation of the method for creating pattern film creation data using this CAD system is as follows. In general, pattern film creation data is data corresponding to components to be mounted on a printed wiring board, that is, component land data (data that is automatically determined once the components to be used are determined) as shown in Figure 10. Registration data consisting of data for determining the position of this component on the printed wiring board, that is, origin coordinate data as shown in FIG. 11, is used. Component land data is used to form lands on the printed wiring board to which terminals of components to be mounted are connected, and includes the relative coordinates from the component reference land to other lands and the size of the lands. It has data indicating the land diameter to be determined. Further, the origin coordinate data indicates the position of the reference land of the above-mentioned component land data in absolute coordinates. The CAD system mentioned above is
By arithmetic processing of registration data consisting of component land data and origin coordinate data, multiple lands for mounting components are automatically digitized and generated.

By the way, in order to create a multilayer printed wiring board, it is necessary to form patterns not only in the outer layer but also in the inner layer, and the patterns in each layer must be electrically connected with through holes. Therefore, they are formed to have a mutually related positional relationship. When creating data for creating a pattern film for the outer layer among these, as described above, each land data for component holes is automatically generated from component data registered in the CAD system. This is because inputting each component land one by one using a digitizer etc. increases the work time, and there is a possibility of data errors due to input errors.Also, if the specifications of each component are different (inch parts, metric parts) This is because input requires a great deal of effort. On the other hand, when creating data for creating a pattern film for the inner layer, all lands are automatically generated from registered component data for the same reason as for the outer layer.

However, in the outermost layer pattern of the board, as shown in Figure 8, a land is required for the conductive through-hole, but in the inner layer, as shown in Figure 9, a land is required only when there is a conductive pattern. It's just that. In other words, lands are generally used for two purposes: to establish continuity with through-holes, and to improve solder paste during soldering, but in the inner layer, they are used to establish continuity with through-holes. It is only necessary for

Therefore, there are many unnecessary lands in the inner layer pattern film creation data automatically created by the method described above. This unnecessary land unnecessarily wears out the drill during drilling using a drill, and also causes serious problems such as shorting between the land and the pattern within the inner layer pattern.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances, and the problems to be solved are caused by unnecessary component hole lands formed in the inner layer of a multilayer printed wiring board. Drill wear during drilling of printed distribution boards and shorting of lands and patterns within the inner layer pattern.

(Means for Solving the Problems) The means taken by the present invention to solve the above problems are as follows: ``A pattern consisting of lands and lines is formed on each layer of a multilayer printed wiring board from a given circuit diagram. When creating a pattern film for forming a pattern on the multilayer printed wiring board using the pattern film creation data formed from the pattern design diagram, The land data for component holes in the film creation data is automatically generated for all lands from the registered component data, and after the pattern data is completed, only the inner layer pattern film creation data is generated, including the land data consisting of the center coordinates and radius of the land, and the land data as described above. Decomposes the pattern design into line data consisting of the coordinates of the end points of the line, its radius, and data indicating that these end points are continuous, and decomposes the pattern design drawing into predetermined sections, and the land data that falls within the sections. , memorize line data for each ward,
One set of land data that falls within this section and another set of line data that falls within the same section are selected, the distance between them is calculated, and from this calculated distance, the inner land is A deletion method for a multilayer board, characterized in that it is determined whether or not the land is connected to a pattern, and for inner land lands that are not connected, the land data is deleted from the pattern film creation data.

Next, the principle of the present invention will be schematically explained using the drawings. The principle used in this invention is as follows. The basic idea of this invention is the third
The pattern (conductor circuit) on the printed wiring board as shown in the figure is divided into a circle (land 10) and a band with semicircular or square ends (true If you think of it as line 20 (padded), then it is. If you think of a pattern in this way, no matter how complex the pattern is, you can reliably realize the pattern by combining the circle (land 10) and the band (true line 20, padded) described above. It is.

Taking as an example the case where a pattern as shown in FIG. 3 is formed on a printed wiring board, this pattern is first used as a land 10 where a terminal of an electronic component is inserted or a through hole is formed. , and a true line 20 as a pattern for electrically connecting these lands 10. In this case, if the true line 20 is bent, another true line is assumed to extend from the bent part. The pattern shown in FIG. 3 is composed of two lands 10 and three true lines 20.

Figures 4A and 4B show the land 10 and true line 20 separately.
As a numerical method for land 10 and true line 20,
First, for the land 10, it is represented by its center coordinates and the radius of the land 10 itself, and for the true line 20, the coordinates of the end point of the true line 20, the thickness (or width), and both end points of the true line 20 are connected. By representing this with data indicating this, each data providing the land 10 and the true line 20 can be used as data consisting of vector quantities.

Using the above vector data, divide the vector data into sections for each inner layer, use a computer to calculate the intersection of lands 10 and lines in each section, and select lands 10 that do not intersect with at least one line. By deleting the data from the film production data, it is possible to effectively reduce wear on the drill during drilling and prevent short circuits between the land 10 and the pattern during the manufacturing process.

(Example) Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a drawing corresponding to the scope of the claims, and shows the steps according to the present invention in order. This FIG. 1 corresponds to the portion from step C to step E in FIG. 2. The procedure shown in Figure 2 shows the procedure for forming a pattern film from a circuit diagram. In step A, a circuit diagram in which necessary electronic components are combined and electrically connected is created using a normal design method. do.

From the circuit diagram created in this way, a pattern design drawing is created in Step B while taking into consideration the size and position of the electronic components, the size of the printed wiring board, and the layout of various electronic components arranged thereon. Thereafter, in step C, data for creating a pattern film is created from the pattern design drawing so that the pattern film can be easily formed using a digitizer or by arithmetic processing. At this time, lands 10 are generated on the inner layers of all parts at once.

Then, in step D, the unnecessary inner layer land 10
Delete. Furthermore, a pattern film is formed using an automatic drawing device at step E based on the data after unnecessary lands 10 have been deleted.

The method of the present invention includes the above steps D shown in FIG.
This will be explained in detail using FIGS. 1 to 9. First, step a in Figure 1
In this step, the lands 10 and true lines 20 are digitized using a digitizer or the like from a pattern design drawing created based on a circuit diagram. At this time, all lands 10 are generated on the inner layers of all parts at once. In this case, each land 10 and true line 20 are decomposed into true line 20 data consisting of the center coordinates and radius of the land 10 and converted into numerical values, as described above.

Next, in step b, the vector data described above is divided into predetermined sections for each layer and stored. Then, in steps c, d, and e, calculation processing to determine whether a set of lands 10 and the true line 20 intersect in a certain section of each layer is performed for all sets and all inner layers, and lands 10 that intersect with the pattern are searched and stored. do. Then, in step f, data other than land 10 is deleted from the pattern film creation data. Examples of deletion of land data other than the intersecting land data are shown in FIGS. 5 to 9. Fifth
7 to 7 show examples of cross-sectional views of a four-layer printed circuit board.

In FIG. 5, data was created using a CAD system that automatically generates lands 10 in the first, second, third, and fourth layers when a component hole is created. FIG. 6 shows the pattern data created after that. In FIG. 6, no pattern is connected to the lands 10 of the third layer. Therefore, at this stage, the isolated land 10 of the third layer is deleted from the film production data. The deleted figure is FIG. 7, and the method of searching for the isolated land 10 is as described above.

Next, an example of displaying the state of each layer in a two-dimensional manner is shown in the eighth section.
9 and 9. FIG. 8 is a partial example of an inner layer in which patterns data have been created after lands 10 have been generated in all layers in correspondence with component holes. Lands A, B, shown in FIG.
Among C, D, E, and F, C and D are isolated lands 10 that are not connected to other patterns. Therefore, at this stage, C and D are selected from the film creation data.
Delete isolated land 10.

The state after deletion is shown in FIG. By eliminating the isolated lands 10 shown in the above figures, it is possible to effectively reduce drill wear during drilling and prevent short circuits between the lands 10 and the pattern during the manufacturing process.

(Effects of the Invention) The effects obtained by the method according to the present invention described above are listed below.

1. Reduce the rate of drill wear in the manufacturing process by eliminating unnecessary inner land 10.

2. By removing unnecessary inner layer lands 10, pattern short circuits with lands 10 before removal can be prevented.

3 Land 10 on all inner layers when creating part data
, the number of parts data to be created is small, and the data creation time is reduced.

4. Since the number of parts data to be created is small, defects due to data creation errors are reduced.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing the procedure for explaining the method according to the present invention, Fig. 2 is a flowchart showing the procedure from creating a pattern film from a circuit diagram, and Fig. 3 is a flowchart showing the procedure for creating a pattern film from a circuit diagram. FIG. 4 is an exploded plan view showing the lands and true lines; FIGS. 5 to 7 are partially enlarged cross-sectional views showing cross-sectional examples of printed circuit boards; FIG. 9 and 9 are plan views showing examples of layer planes of the printed circuit board. Also, Fig. 10 is a plan view showing an example of component land data in numerical form, Fig. 11 is a plan view showing origin coordinate data in numerical form, and Fig. 12 shows the relationship between origin coordinates and component lands. FIG. Explanation of symbols: 10...Land, 20...True line.

Claims (1)

[Claims] 1 Create a pattern design drawing for forming a pattern consisting of lands and lines on each layer of a multilayer printed wiring board from a given circuit diagram, and use data for creating a pattern film formed from this pattern design drawing to create the multilayer printed wiring board. When creating a pattern film to form a pattern on a printed wiring board, all lands are automatically generated from the registered component data for land data for component holes in the pattern film creation data, and the pattern data is completed. After that, only the inner layer pattern film creation data is divided into land data consisting of the center coordinates and radius of the land, and line data consisting of the coordinates of the end point of the line, its radius, and data indicating that these end points are continuous. disassemble the pattern design drawing into predetermined sections, and store the land data and line data that fall within the sections for each section;
One set of land data that falls within this section and another set of line data that falls within the same section are selected, the distance between them is calculated, and from this calculated distance, the inner land is A method for deleting unnecessary lands in a multilayer board, characterized by determining whether or not they are connected to a pattern, and deleting the land data of unconnected inner layer lands from the pattern film creation data.