JP4620971B2 - Display method and display device - Google Patents

Description

  The present invention relates to an electric field analysis result display method.

  Conventionally, electronic devices and precision devices have been designed for the purpose of high efficiency and high performance through analysis using electric field simulation. Typical simulation methods include the finite element method and the difference method. In such a technique, a two-dimensional electric field simulation is actively performed on the assumption that the analysis target is infinitely long in the depth direction. The reason is that the time required for the simulation is short, and there are many cases that can be handled in two dimensions. For example, an analysis object taken up in “Konaga: Two-dimensional simulation of charging roller for electrophotography, Japan Hardcopy 1999 paper” relates to an electrophotographic image forming apparatus used in a printer or a copying machine. In this image forming apparatus, the charging, exposure, development, transfer, and fixing processes are mainly performed around a cylindrical photosensitive drum that is long in the axial direction. There are many problems that can be handled. In the above-described example, the two-dimensional electric field simulation is applied to the charging process, and sufficient problems can be solved.

  On the other hand, in order to evaluate the results of these two-dimensional electric field simulations, equipotential lines (potential contour lines) are drawn from the potentials that are the simulation results, or the potential values between the equipotential lines are color-coded in stages. There has been used a method of performing graphic drawing by drawing a solid image or drawing an electric field direction and intensity (electric field vector) with an arrow or the like. However, with this method, the value of the charge density accumulated on the boundary line between different objects (which becomes a boundary surface when considering the depth direction of the actual object but becomes a boundary line when viewed in a two-dimensional section) Could not display. The reason will be described with reference to FIG. 2, which is an example of the above-described electrophotographic charging process. In FIG. 2, reference numeral 120 denotes a charging roller having electrical conductivity and relative dielectric constant, 121 denotes an air region, and 122 denotes a photoreceptor constituting the surface of the photosensitive drum. Further, 123 is a boundary line on the inner side of the charging layer, 124 is a boundary line between the photosensitive member and the air region, 125 is a boundary line between the charging roller and the air region, and 126 is a boundary line on the inner side of the charging roller. It is. Here, FIG. 2 is a cross-sectional view (xy plan view) when the cylindrical roller is cut perpendicular to the axial direction, and shows only the vicinity where the charging roller 120 and the photosensitive member 122 are in contact with each other. In FIG. 2, when a negative potential of 0 V is applied to 123 and 126 of the boundary lines, charges are accumulated only on the boundary lines 123, 124, 125, and 126. Here, it is important for the operator to grasp the distribution state of these charged charges in addition to the potential distribution, and it is desirable to display the charge density distribution in graphics. However, when the charges on the boundary line are color-coded for each value and displayed in graphics, there is a drawback that it is very difficult to see because the lines are only color-coded.

In order to solve such a problem, in “Kamonaga et al .: Simulation of peeling discharge in paper transport transfer belt system, Japan Hardcopy 2001 paper”, the boundary line has a thickness that is not actually in the xy plane on the display. A virtual surface is created on a two-dimensional plane and the charge density is displayed in different colors, and the charge density on the boundary surface is easily displayed and displayed in graphics.
Kamonaga et al .: Simulation of peeling discharge in paper transport transfer belt system, Japan Hardcopy 2001 Proceedings

  However, the above method has a problem. The reason will be explained. If the above-mentioned method is applied to the model of FIG. 2, it will become like FIG. In FIG. 3, 131 is a virtual surface when the boundary line 123 is thick in the negative y direction, and 132 and 133 are virtual surfaces when the boundary lines 125 and 126 are thick in the center direction of the roller 120, respectively. Surface. All these virtual planes are created in the xy plane. At this time, the charge density is color-coded and displayed on the virtual planes 131, 132, and 133. For example, when the charge density and the equipotential line are to be viewed simultaneously, the charge density or the equipotential line is displayed on the virtual plane. Only one of them can be drawn, or it will be displayed overlapping and difficult to see.

  In addition, since the geometrical shape of the virtual surface and the analysis model are displayed on the same xy plane, the geometrical shape displayed including the virtual surface is different from the actual object shape, and results are misunderstood or evaluation errors. Could cause. Further, since the photosensitive member 122 is very thin, a virtual surface cannot be created. For this reason, in order to display the charge density of the boundary line 124 in addition to the virtual surfaces 131, 132, and 133 shown in FIG. There was a drawback that it would be difficult to view the faces simultaneously.

  The present invention has been made in view of these problems, and an object of the present invention is to make it possible to draw other information such as equipotential lines simultaneously and accurately with respect to the charge density as a result of the two-dimensional electric field simulation. .

  In order to achieve the above object, according to the present invention, a display device for analysis results of a two-dimensional electric field includes a CPU, a memory, an input means, and a display means, and the CPU passes through the input means. Reading the position, potential and charge density of each node belonging to the boundary line between different objects in the two-dimensional electric field into the memory, and the CPU based on the position and potential of each node Of the electric field analysis result, the potential distribution is drawn on a plane parallel to the xy plane in the space displayed on the display means in three-dimensional graphics, and the CPU is on the plane on which the potential distribution is drawn. An input for designating a boundary line that is a display target of the charge density distribution in the analysis result of the two-dimensional electric field and a depth length of the boundary surface created based on the boundary line is input via the input unit. Received from the operator, the CPU extends the boundary line in the z direction in the space where the three-dimensional graphics are displayed by the depth length, creates the boundary surface, and the CPU determines the position of each node. Based on the charge density, a charge density distribution on the boundary line is drawn on the boundary surface in a space displayed on the display means in three-dimensional graphics.

  In the display method and display device for displaying the results of the two-dimensional physical analysis, the physical quantity on the boundary surface is displayed on the surface obtained by extending the boundary surface of the analysis model in the three-dimensional direction. The contour lines can be displayed easily. In addition, the two-dimensional geometric shape of the analysis model can be displayed without being changed. Furthermore, since the depth length of the boundary surface can be changed, even if the charge density of a plurality of boundary lines is displayed, the boundary surface can be displayed easily. Therefore, the physical quantity on the boundary as the two-dimensional physical analysis result and the contour line of the physical quantity in the xy plane can be drawn simultaneously and accurately.

  Embodiments of the present invention will be described below.

(First embodiment)
FIG. 4 is a configuration diagram of an input device, an output device, and a computer for performing the display method according to the embodiment of the present invention. In the figure, reference numeral 1 denotes a keyboard or mouse, which is an input device for specifying a result file of a two-dimensional electric field simulation, specifying a boundary line for displaying a charge density distribution, and operating a viewpoint and position in three-dimensional graphics. Reference numeral 2 denotes a display device for drawing the analysis model, the equipotential diagram, and the result of the charge density distribution with graphics. 3 is a computer. An input / output circuit (I / O) 4 reads a signal from the input device 1 and outputs a signal to the output device 2. A ROM 5 stores a processing program and fixed data for displaying the result as three-dimensional graphics. Reference numeral 6 denotes a RAM which is a data memory for storing processing data, and reference numeral 7 denotes a central processing unit (CPU) which executes the processing program.

  Next, the operation of the present embodiment will be described.

  FIG. 5 is a flowchart showing the operation of the present embodiment. First, the file names of the two-dimensional mesh data, boundary data, and simulation result data are input from the keyboard or selected by the mouse, read by the I / O 4, and stored in the RAM 6 (S1). Here, the two-dimensional mesh data refers to the node numbers i (= 1, 2,..., Np: total number of nodes) and the two-dimensional coordinate values ( xi, yi). The boundary data is information indicating which boundary line each node of the mesh data belongs to, and the simulation result data is the potential (V1, V2,..., Vnp), charge at each node of the mesh. Information on density (q1, q2,..., Qnp).

  After each data is read in S1, the equipotential lines in the xy plane are displayed in graphics in S2. In the equipotential line drawing at S2, the drawing potential value Vxi (i = 1, 2,..., 16) obtained by dividing the maximum value and the minimum value of the potential of each node into N (here, N = 15) is obtained. The calculation is performed by the central processing unit (CPU), and the output device 2 draws equipotential lines at these drawing potential values Vxi in the xy plane. Here, the equipotential lines are represented as straight lines within each element. This drawing method is general in equipotential line drawing technology. Since the equipotential line to be drawn is a straight line within each element, the respective coordinate values (X1j, Y1j) and (X2j, Y2j) (j = 1, 2,... , Na: number of equipotential lines in all elements), and the information is stored in the RAM 6. Further, here, in drawing, the minimum potential value level is black, the maximum potential value level is white, and the color is grayed out according to the potential level between equipotential lines (gray scale). This is also a known technique. .

  In the process parameter input S3, the boundary line for displaying the charge density distribution is designated by the keyboard or the mouse, and the depth length of the surface for displaying the charge density of the boundary line is designated, and the data is stored in the RAM 6. To store. Here, the boundary line 124 and the depth length D among the boundary lines 123, 124, 125, and 126 are designated in FIG. Next, the nodes on the boundary line 124 are rearranged in ascending order of the x-coordinate values to obtain coordinate values (xpk, ypk) (k = 1, 2,..., Nb: the number of nodes on the boundary line 124). Such a node Npk and the charge density value qpk of the node are stored in the RAM 6. That is, the boundary line 124 is a set of sides composed of two points of the node Npk: coordinate value (xpk, ypk) and Np (k + 1): coordinate value (xp (k + 1), yp (k + 1)).

  Next, in S4, the charge density distribution of the boundary line 124 designated in S3 is displayed. First, coordinate values (xi, yi) in the input two-dimensional mesh data, coordinate values (xpk, ypk) on the boundary line 124, coordinate values (X1j, Y1j) and (X2j, Y2j) representing equipotential lines Are expanded to three-dimensional coordinate values (xi, yi, 0), (xpk, ypk, 0), (X1j, Y1j, 0), (X2j, Y2j, 0), respectively. Next, with respect to the coordinate values on the boundary line 124, a surface is created in a three-dimensional direction while newly generating a node that becomes Npk ′ (xpk, ypk, D). The result is shown in FIG.

  In FIG. 6, reference numeral 100 denotes a three-dimensional virtual surface obtained by extending the boundary line 124 in the z direction by a depth length D. This virtual surface includes four nodes (1) Npk: coordinate values (xpk, ypk, 0), (2) Npk ′: coordinate values (xpk, ypk, D), (3) Np (k + 1) ′: coordinate values (xp (k + 1), yp (k + 1), D), (4) Np (k + 1): coordinates It is a set of surface elements composed of values (xp (k + 1), yp (k + 1), 0).

  Furthermore, the newly generated charge density value qpk ′ of Npk ′ is set to the same value as the charge density value qpk at all the nodes Npk on the boundary 124. These pieces of information are created by a central processing unit (CPU) and stored in the RAM 6. At this time, the elements constituting the three-dimensional virtual surface 100 are composed of four nodes, and each of the four nodes has a charge density value.

  Using these values, contour lines of the charge density in the element plane are drawn, and the space between the contour lines is filled with a color corresponding to the value of the charge density. As described above, a technique for drawing and painting contour lines in an element plane composed of nodes having values to be displayed is already known. Here, when the charge density value is q, the color value to be filled is obtained by dividing the difference between the minimum charge density value qmin and q by the difference between the minimum charge density value qmin and the maximum charge density value qmax. Since the color value ranges from 0 to 1, the color may be determined on a gray scale, with black indicating the minimum value being 0 and white indicating the maximum value being 1.

  FIG. 1 shows a graphic display as a bird's eye view through the processes of S1 to S4. In the normal two-dimensional display, the portion 124 where charges are accumulated is only displayed as a line, which is difficult to see. However, as shown in FIG. 1, the charge density is displayed on the surface 100 extended by the depth length D in the z direction, and a bird's eye view. The charge density and the equipotential diagram of the xy planes 120 and 121 can be displayed simultaneously. In order to view the equipotential lines of the two-dimensional plane (photosensitive member 122 shown in FIG. 2) hidden in the three-dimensional virtual surface 100 in FIG. 1, for example, the coordinate values (x1, y1, z1) of the current viewpoint are used. However, the viewpoint may be changed so as to see from (x1, -y1, z1). To change the viewpoint, a mouse or a keyboard may be used. Such a viewpoint change can be easily realized with current graphics technology. Furthermore, since the virtual plane is created by extending in the z direction and the geometric shape on the two-dimensional plane (xy plane) is not changed, there is no misrecognition of results and evaluation errors in the displayed geometric shape.

(Second Embodiment)
An embodiment in which there are a plurality of boundary lines for performing charge density display described in Embodiment 1 will be described. The apparatus for carrying out the display method according to the present embodiment is the same as that of the first embodiment.

  Next, the operation of the present embodiment will be described.

  Flows S1 to S2 shown in FIG. 5 are the same as those in the first embodiment.

  In the processing parameter input S3, the boundary line for displaying the charge density distribution is specified by the keyboard or the mouse, and the depth length D of the surface for displaying the charge density of the boundary line is designated, and the data is stored in the RAM 6. Store. Here, among the boundary lines 123, 124, 125, and 126 in FIG. 2, the boundary lines 124 and 123 are designated as depth lengths D and D ', respectively. However, D '> D. Next, the nodes on the boundary line 124 are rearranged in ascending order of the x coordinate values to become coordinate values (xpk, ypk) (k = 1, 2,..., Nb: the number of nodes on the boundary line 124). Such a node Npk and the charge density value qpk of the node are stored in the RAM 6. Further, the nodes on the boundary line 123 are rearranged in ascending order of the x coordinate values so that the coordinate values (xqk, yqk) (k = 1, 2,..., Nc: the number of nodes on the boundary line 123) are obtained. A random node Nqk and the charge density value qqk of that node are stored in the RAM 6. That is, the boundary line 124 is a set of sides composed of two points of node Npk: coordinate value (xpk, ypk) and Np (k + 1): coordinate value (xp (k + 1), yp (k + 1)). Reference numeral 123 denotes a set of sides composed of two points: node Nqk: coordinate value (xqk, yqk) and Nq (k + 1): coordinate value (xq (k + 1), yq (k + 1)).

  Next, in S4, the charge density distribution of the boundary lines 123 and 124 designated in S3 is displayed. First, the coordinate values (xi, yi), the coordinate values (xpk, ypk) on the boundary line 124, the coordinate values (xqk, yqk) on the boundary line 123, and equipotential lines in the input two-dimensional mesh data are expressed. The coordinate values (X1j, Y1j) and (X2j, Y2j) are converted into three-dimensional coordinate values (xi, yi, 0), (xpk, ypk, 0), (xqk, yqk, 0), (X1j, Y1j, 0), respectively. ), (X2j, Y2j, 0).

  Next, with respect to the coordinate values on the boundary lines 124 and 123, a new node is generated as Npk ′ (xpk, ypk, D) and Nqk ′ (xqk, yqk, D ′). create. The result is shown in FIG. In FIG. 7, reference numeral 100 denotes a three-dimensional virtual surface obtained by extending the boundary line 124 by a depth length D in the z direction. This virtual surface includes four nodes (1) Npk: coordinate values (xpk, ypk, 0), (2) Npk ′: coordinate value (xpk, ypk, D), (1) Np (k + 1) ′: coordinate value (xp (k + 1), yp (k + 1), D), (4) Np (k + 1): coordinate It is a set of surface elements composed of values (xp (k + 1), yp (k + 1), 0).

  Furthermore, the charge density value qpk ′ of the newly generated Npk ′ is set to the same value as the charge density value qpk at all the nodes Npk on the boundary 124. Reference numeral 101 denotes a three-dimensional virtual surface obtained by extending the boundary line 123 by a depth length D ′ (D ′> D) in the z direction. This virtual surface includes four nodes (1) Nqk: coordinate value (xqk, yqk, 0), (2) Nqk ′: coordinate values (xqk, yqk, D ′), (3) Nq (k + 1) ′: coordinate values (xq (k + 1), yq (k + 1), D ′), (4 ) Nq (k + 1): A set of plane elements composed of coordinate values (xq (k + 1), yq (k + 1), 0). Further, the newly generated charge density value qqk ′ of Nqk ′ is set to the same value as the charge density value qqk at all nodes Nqk on the boundary 123.

  These pieces of information are created by a central processing unit (CPU) and stored in the RAM 6. At this time, the elements constituting the three-dimensional virtual surfaces 100 and 101 are composed of four nodes, and each of the four nodes has a charge density value. Therefore, using these values, the contour lines of the charge density may be drawn in the same manner as in the first embodiment.

  In this way, the depth length D of the three-dimensional virtual surface 100 and the depth length D ′ of the three-dimensional virtual surface 101 are different from each other, and the depth length of the virtual surface 101 that is far from the viewpoint is increased, By setting D ′> D, the virtual surface 101 is not hidden and displayed in 100, and even if there are a plurality of virtual surfaces, it is not difficult to see.

Figure showing a display example Diagram showing charger model Diagram showing conventional charge density display Configuration diagram of an apparatus according to an embodiment Figure showing a flowchart Illustration of creating a virtual surface in 3D display The figure explaining the virtual surface when there are multiple virtual surfaces

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Three-dimensional virtual surface 120 Charging roller 121 Air area 122 Photoconductor 124 Photosensitive drum surface

Claims (2)

In a method for displaying a two-dimensional electric field analysis result by a display device comprising a CPU, memory, input means, and display means ,
The CPU reads the position, potential and charge density of each node belonging to the boundary line between different objects in the two-dimensional electric field into the memory via the input means;
The CPU draws the potential distribution of the analysis result of the two-dimensional electric field on a plane parallel to the xy plane in the space displayed on the display means by the three-dimensional graphics based on the position and potential of each node. A first drawing step,
The CPU includes a boundary line that is a display target of a charge density distribution in the analysis result of the two-dimensional electric field on a plane on which the potential distribution is drawn, and a depth length of a boundary surface created based on the boundary line An input step of accepting an input for designating from an operator via the input means;
A creation step in which the CPU extends the boundary line by the depth length in the z direction in the space where the three-dimensional graphics are displayed, and creates the boundary surface;
A second drawing step in which the CPU draws a charge density distribution on the boundary line on the boundary surface in a space displayed in three-dimensional graphics on the display unit based on the position of each node and the charge density; display method characterized in that it comprises and. In the display device of the analysis result of the two-dimensional electric field, a CPU, a memory, an input means, and a display means are provided,
The CPU reads, via the input means, the position of each node belonging to the boundary line between different objects in the two-dimensional electric field, the potential, and the charge density into the memory,
The CPU draws a potential distribution in the analysis result of the two-dimensional electric field on a plane parallel to the xy plane in the space displayed in the three-dimensional graphics on the display unit based on the position and potential of each node. And
The CPU includes a boundary line that is a display target of a charge density distribution in the analysis result of the two-dimensional electric field on a plane on which the potential distribution is drawn, and a depth length of a boundary surface created based on the boundary line Input from the operator via the input means,
The CPU extends the boundary line by the depth length in the z direction in the space where the three-dimensional graphics are displayed, and creates the boundary surface.
The CPU draws a charge density distribution on the boundary line on the boundary surface in a space displayed in three-dimensional graphics on the display unit based on the position of each node and the charge density. Display device.

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