JPS63301019A - Data generating device for scanning optical system - Google Patents

Abstract

PURPOSE:To generate lens data automatically by setting up coordinate conversion data on a scanning optical system by a function means which is set in a CPU according to information in an external storage device. CONSTITUTION:In the CPU 12, a 1st means 16 which generates coordinate conversion data at the reference position of the scanning system with the information in the external storage device 14 and a 2nd means 17 which generate coordinate conversion data at the rotary position of the scanning system are set functionally. Then the 1st means 16 generates the coordinate conversion data as to a scanning surface at the reference position of the scanning part member from information and a coordinate code which specify the scanning member in a virtual optical system where the optical axis of the scanning surface of the scanning member is aligned with the optical axis of an incidence optical system. The 2nd means 17 generates the coordinate conversion data on the scanning surface at the rotary position of the scanning member according to rotational angle information from the reference position. Consequently, the lens data is constituted automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a data creation device for a scanning optical system having a scanning member, such as a polygon mirror (rotating polygon mirror), in which the center of the scanning surface moves by rotation. .

Conventional Technology When designing an optical system, it is convenient to be able to display the behavior of light rays in the optical system by ray description, but in some optical systems, for example, optical systems using polygon mirrors, the state of the rays can be changed by a scanning member. There are things that change. When designing such a scanning optical system, it is desirable to draw a light beam corresponding to the movement of the scanning member on the same screen together with the scanning member.

In such a case, it is reasonable to use a computer to perform calculations such as ray tracing, but as a premise, data for a scanning system having a polygon mirror must be created. Conventionally, such lens data creation was performed individually by designers.

Problems to be Solved by the Invention However, in such a scanning optical system, the entire lens system does not share one optical axis (center axis of the lens), the optical axis is tilted, and moreover, due to rotation, Since the scanning plane is optically complex in that the center of the scanning plane moves, it is a very difficult task for the designer to create data for such a system. Moreover, considering that it is necessary to create not only lens data for the reference position (but also lens data corresponding to rotation), this task becomes extremely difficult.

Therefore, an object of the present invention is to automatically configure lens data for a scanning system by inputting data regarding the scanning member to the CPU under the assumption that the entire lens system shares one optical axis. It's about doing.

Means for Solving Problems A data creation device for a scanning member in which the center of a scanning surface moves by rotation, comprising: a CPU, an external storage device, an input device, and a computer that generates data based on information in the external storage device. and a functional means set within a virtual optical system, wherein the functional means specifies the scanning member in a virtual optical system in which it is assumed that the optical axis of the scanning surface of the scanning member coincides with the optical axis of the input optical system. As information, the surface number input by the input means, the distance from the rotation axis to the scanning surface, the reference reflection angle, the center coordinates, the cosine in the direction of the rotation axis, and the coordinate system code for specifying the center coordinates and the cosine in the direction of the rotation axis. first means for establishing coordinate transformation data for a scanning plane with the scanning member at a reference position; A data creation device for a scanning optical system, characterized in that the device is a second means for establishing coordinate transformation data for a scanning plane at a rotational position.

Coordinate conversion data for converting the coordinates of the working virtual optical system into the coordinates of the true optical system is stored in the first and second coordinates based on information in the external storage device.
Automatically determined by means.

Therefore, the designer only needs to input the simple information needed into the CPU. At that time, by adjusting the input standard reflection angle information and direction cosine information of the rotation axis, you can set a scanning member where the scanning plane and the rotation axis are parallel or non-parallel, or The installation direction and scanning direction can be changed.

Embodiment The scanning optical system to which the present invention is applied has a scanning member that has a large number of scanning surfaces (reflecting surfaces) such as polygon mirrors.
For example, it is a scanning system that includes a member that has only one scanning surface but is rotatable around a rotation axis and can deflect the incident light beam. Good too. However, in the following embodiments, a scanning optical system having a polygon mirror will be exemplified and explained. Prior to that, the outline of this type of scanning optical system will be explained using an example of use shown in FIG.

Figure 2 shows the optical system of a laser printer having a polygon mirror (1), (2) is a semiconductor laser light source, and the laser beam emitted from the light source (2) is collimated by a collimator lens (3). The beam is corrected by the light, and the difference in vertical and horizontal spread of the beam is corrected to a circular cross section by a cylindrical lens (4), and a polygon mirror (
1) Give. The polygon mirror (1) is configured to rotate around an axis (18), and provides the light beam (e) that hits its reflecting surface to the output lens system (6). Of the output lens system (7) is a toroidal lens that optically compensates for the inclination of the light beam due to mechanical backlash of the polygon mirror, and behind it is a toroidal lens that adjusts the beam scanning speed on the photoreceptor drum (11) at a constant speed. Three f-theta lenses (8), (9), and (10) are provided to achieve this. The laser beam finally converges on the surface of the photoreceptor drum (11) to form dots thereon, and the combination of these dots draws characters and figures.

The position of the reflected light of the light emitted from the light source (2) and hitting the polygon mirror (1) differs depending on the angle of the reflective surface of the polygon mirror (1). For example, the rotational position of a polygon mirror (
When the angle) is at a predetermined reference position, the reflected light passes through the center of the output lens system (6) as shown in Figure 2, but when it rotates in any direction from that position, the output lens corresponding to that direction passes through the center of the output lens system (6). Displaced toward one end of the system (6).

As mentioned earlier, in an optical system that includes a polygon mirror (1), the entire lens system does not share one optical axis, as shown in Figures 3 (b) and 4 (b). The two optical axes (X) (Xi) on the incident side and the reflective side are tilted to each other. Such a state is hereinafter referred to as "the surface is eccentric/inclined." In other words, the coordinate system of a certain surface is defined as its X axis (
This means that the coordinate system of the next surface cannot be obtained by moving parallel to the central axis of the lens. 20 "Coordinate system of a surface" means that the origin is the surface vertex of the surface (in the case of a reflective surface, the center point of the reflective surface), the X axis is taken in the normal direction to the surface vertex, and the A coordinate system formed by setting the Y-axis and Z-axis in a tangential plane.Normally, the Y-axis is placed in the plane of the paper, and the Z-axis is placed perpendicular to the plane of the paper.

For example, in Figure 3 (C), the B plane (scanning plane of the polygon mirror) is eccentric/inclined with respect to the rear surface (19) of the block, and the front surface (20) of block C is eccentric/inclined with respect to the B plane. . That is, the B surface is not in the coordinate system oxyz that is translated in parallel to the X-axis direction of the block A, but is tilted, and is eccentric/tilted, resulting in a hatched state. Also, the front surface of block C is at an angle ω/2 with respect to the X axis (xi axis) of surface B.
However, the coordinate system of the tilted surface is not on the X axis of surface B, and similarly eccentricity/
It is sloping.

On the other hand, in FIG. 3(a), the rear surface of block A,
The next surface, the virtual polygon scanning surface B (a dummy surface, where the medium on both sides of the surface is essentially "air"), is not eccentric/inclined. If Figure 3 (b) and Figure 4 (b) are imitated in Figure 2, (2) is the light source, and block A is the input including lenses (3), (4), etc. in Figure 2. Lens system block C is an output lens system (6). Furthermore, block D is a photosensitive drum (11).

Next, a mathematical expression of the eccentricity/inclination will be described. Now, suppose that the old coordinate system o-xyz is eccentric/inclined and becomes new coordinates 0"-X'Y'Z' as shown in FIG.

An arbitrary point P expressed in both the new and old coordinate systems is (X', Y
', Z'), (X, Y, Z), (X',
Y', Z'), (X.

Y, Z), the relationship expressed by equation (1) shown in FIG. 12 occurs. Here, the coordinates of the new point 0' expressed in the old coordinate system 0-XYZ are 0° (Xo, Y,, ZO), the old coordinate axes (OX, OY, OZ) and the new coordinate axis (0° , O
'Y', O'Z') (7) The direction cosine of each angle is α
When the unit hectare on the new coordinate axis is expressed in the old coordinate system, the equation (2) in FIG. 12 is obtained. Next, when the rotation matrix in (1) 2 and the origin movement matrix are multiplied, equation (1) becomes equation (3) in FIG. 12.

Therefore, 12 pieces of data representing origin movement and rotation Xo+Y
o+Zo*α1 blind αlit α13+α21+α22+
α23. α, 1. If α3□ and α33 are given, any coordinate transformation can be calculated from equation (3). From now on, the matrix of equation (3) will be referred to as the "eccentricity/tilt matrix."

For example, considering the movement of the origin in the X-Y plane and the rotation of θ around the Z axis, the eccentricity/inclination matrix becomes as shown in equation (4) shown in FIG.

In the present invention, lens data is established by determining the eccentricity/inclination matrix described above for the scanning optical system as shown in FIG. 3 (B) and FIG. 4 (B). The schematic configuration is shown.

In Fig. 1, (12) is a CPU (central processing unit), (13) is an input means such as a keyboard, and (14) is an external storage device such as a floppy disk. / Built-in program information for determining the slope matrix.

Although (15) is a CRT display, this is not necessarily necessary for the configuration of the present invention. CPU (1
2) a first means (16) for establishing a coordinate transformation data eccentricity/inclination matrix at a reference position of the scanning system;
) and a second means (17) for creating coordinate transformation data at the rotational position of the scanning system are functionally set.

The first means (16) inputs the input means as information for specifying a scanning member such as a polygon mirror in a virtual optical system in which the optical axis of the scanning surface of the scanning member coincides with that of the incident optical system. The surface number input by , the distance from the center to the scanning surface (e.g. radius of the inscribed circle), the center coordinates, the cosine in the direction of the rotation axis, the reference reflection angle, and the coordinate system for specifying the center coordinates and the cosine in the direction of the rotation axis. Establishing coordinate transformation data for the scanning plane at the reference position of the scanning member from the code.

Further, the second means (17) establishes coordinate transformation data of the scanning surface at the rotational position of the scanning member based on the rotational angle information from the reference position also inputted by the inputting means (13).

The operation of the data creation device shown in FIG. 1 will be described below with reference to flowcharts and the like.

In FIG. 10, before the CPU (12) operates,
First, various data are input using the input means (13). As for the data, first, the lens surface number (Ll) (L2)...(
L6), the curvature of each surface, the interplanar spacing, and the refractive index (representing the medium). In addition to these data, the reference reflection angle (ω), the center position (center coordinates) of the polygon mirror (1), the diameter of the inscribed circle (d) [see Figure 4 (c)], and the direction of the rotation axis (18) Enter cosine, rotation angle, etc. Here, the reference reflection angle is the surface in front of the scanning surface (B) of the polygon mirror (1) in the optical system in FIG. 3 (B), that is, the rear surface (1) of the block (A).
9) and the surface one after the scanning surface (B), that is, the front surface (20) of the block (C). If the scanning member is not a polygon mirror but has only one reflective surface, for example, the distance from the center of rotation to the reflective surface is input instead of the diameter of the inscribed circle.

Furthermore, data to be input includes a coordinate system code, and the center coordinate and direction cosine are input with respect to this coordinate system code. For example, consider the following three types of coordinate system codes.

Coordinate system code 1: Coordinate system 0□- regarding the previous surface of the virtual polygon scanning surface [the rear surface of block A in Figure 3 (a)]
Xz Yz Zz Coordinate system code 2: Coordinate system 0I-x, y, z regarding the first surface of the lens system [the front surface of block A in FIG. 3 (a)].

Coordinate system code 3: Set the vertex 0 of the virtual polygon scanning plane [Fig. 3 (A), Fig. 4 (A)] as the origin 03, and set the X3 axis parallel to the optical axis (center axis) of block C after folding. A coordinate system having 03

In addition, in Figures 3 and 4, the rear side of the polygon scanning plane (B) of the virtual optical system shown in Figure (A) is folded back around the point (0) of the virtual polygon scanning plane (B) of the virtual optical system shown in Figure (B). shall be taken as a thing. At this time, point (0) is not necessarily the actual point through which the light beam passes. The relative position of the portion behind the polygon scanning plane (B) is assumed to be the same as before folding. The polygon mirror (1) rotates around the rotation axis, but the front surface (20
) does not change its position from before rotation. In FIG. 3 and FIG. 4, the direction of the rotation axis of the polygon mirror (1) is different, and the scanning direction is also different.

Here, when inputting each data manually, the external storage device (1) is displayed on the screen of the CRT display (15) shown in FIG.
The table shown in FIG. 9 is displayed based on the information in 4). Here, symbols (a) to (m) shown in parentheses and (
n2) to (n+.) are added for convenience and are blank on the actual screen. This blank area is an input area and will be referred to as a "field" hereinafter. The three coordinate system codes mentioned above are already prepared, and all you have to do is select them with numbers 1, 2, and 3. When code 0 is displayed in the polygon mirror setting status code field at the top of the screen, the current situation is as shown in Figures 3 and 4 (a), where there is no wrapping, and code 1 is displayed. The time indicates that the current situation is at a turning point as shown in Figure (b).

PF at the bottom of the screen indicates a faction, and if you select PFil when the polygon mirror setting situation is set to code 1,
This situation is erased, the polygon mirror setting situation code becomes 0, and a situation where there is no turning back is set. Data input by the input means (13) is performed sequentially while looking at the screen and specifying an input location with a cursor.

However, the lens surface number, curvature of each surface, surface spacing, refractive index, etc. are input separately. These are basic lens data and are always input when designing any lens.

When the above various data are input, the CPU (1
2) First, read the surface number you want to make into a polygon mirror in (#1). It is checked in (#2) whether or not it is a virtual polygon scanning plane. The judgment is made based on the refractive index on both sides of the lens surface number of the input data, and when both sides have the refractive index of air, the specified surface is determined to be a virtual polygon surface,
Proceed to the next step (113), but if not, an error message is issued to notify the necessity of data replacement.

In that case, the operator re-enters field (b) on the screen of FIG. 9 so that it is the correct plane number that will be the polygon scanning plane.

(#3), the diameter of the inscribed circle of the polygon mirror is obtained from field (d) in Figure 9, field (g) (h) (i)
The center coordinates of the polygon mirror are read, the coordinate system code is read from the field (f), the reference reflection angle ω is read from the field (m), and the cosine of the rotation axis direction is read from the fields (j), (k), (I!,).

Although it has been explained here that data is read from the fields on the screen for convenience, in reality, data is read from memory locations in the memory corresponding to these fields.

Next, in (#4), the center coordinates of the polygon mirror are changed to the coordinate system (0-XYZ) of the virtual polygon scanning plane before folding.
). Note that the operation in (#4) will be explained in detail later.

After the above coordinate transformation, the actual coordinates of the surface vertices and the inclination angle of the surface of the polygon mirror are determined in (#5) with respect to the coordinates o-xyz. The inclination angle of the surface is ω from the standard reflection angle ω and the law of reflection.
/2. On the other hand, the coordinates of the surface apex can be determined from the relationship among the center coordinates of the polygon mirror, the direction cosine of the rotation axis, the diameter of the inscribed circle, and the inclination angle of the reflecting surface.

Using the coordinates of the new surface apex found in (#5) and the inclination angle of the reflecting surface, the reference position (0"-
Find the eccentricity/inclination matrix of the polygon mirror surface at (X'Y'Z').

Next, in (#7), the B surface is made a reflective surface (typical processing includes the refractive index after the B surface, the distance value between the surfaces,
(reverses the sign of the radius of curvature of the surface).

(#8), block C regarding the coordinate system o-xyz
Find the coordinates of the surface vertices and the inclination angle of the surface in front of the surface. From the geometrical relationship, the surface vertex X = -tcosω, Y = -t
With sinω, the slope of the surface becomes φ−ω. Here, L is the third
This is the distance value between the virtual polygon scanning plane (B) specified in the diagram (A) and the front surface of block C.

Next, in (#9), the eccentricity/inclination matrix of the front surface of block C is determined. One method will be described using FIG. In Figure 8, the coordinate system of the polygon mirror surface is 0°-x'
y'z', eccentricity/
The coordinate system of the front of block C when it is not tilted is ○,
-X, Y, Z4, and the coordinate system of the front surface of block C in the eccentric/tilted state is 04° -X, 'Y, 'Z4'.

Using the result of (#8) to find P corresponding to the matrix of equation (3), equation (5) in FIG. 12 is obtained.

Also, the eccentricity/inclination matrix obtained in (l16) is
Then, equation (6) in FIG. 12 holds true.

Here, o'-x'y'z" and o, -x, y, z4
Find the matrix R. This Ma[・Rinox R is a simple translation of the coordinate system in the X-axis direction (3)
It can be easily obtained from the equation, as shown in equation (7) in FIG.

From equations (5), (6), and (7), the eccentricity/inclination matrix P·(R-Q)-' of the front surface of block C is determined as shown in equation (8) in FIG.

Next, at (#lO) in the flowchart, the height H of the polygon surface is determined from the field (c) in FIG. 9 [FIG. 4 (
b), see FIG. 6(a)], and determine the shape and size of the polygon mirror surface from these and the diameter of the inscribed circle to limit the range through which the light rays can pass. This is a generally necessary condition for regulating light flux in the configuration of a lens system. In addition, instead of reading the number of polygon faces and the quotient of the polygon mirror in (#10), it is also possible to read them in the previous (#3), but for practical purposes, it is preferable to read them in (#3).
It shall be read with . Next, the process proceeds to (#11), and rotation angle data of the polygon mirror from the reference position is read from fields (n2) to (r++.). At this time, if rotation angle data has not been input, the process ends.

If rotation angle data is included, the number of rotation angles (
Repeat #12) to (#14). Polygon mirror is
It rotates around the rotation axis, and by making it possible to specify the direction cosine of the rotation axis, the setting direction of the polygon mirror can be changed as shown in Figures 3 (B) and 4 (B). Is possible. At this time, the cosine in the direction of the rotational axis is input in one of the three coordinate systems shown in (4). (Il13) calculates the eccentricity/inclination matrix when the polygon mirror is rotated by θ from the reference position.
Therefore, one method will be described here.

First, find the transformation matrix S between the coordinate system 0"-x'y'z" at the reference position and the coordinate system O""-x"y"z" when rotated by θ.The equation is shown in Figure 12. (
9) Shown as equation. Coordinate system of virtual polygon surface 0-xyz
Find the transformation matrix between θ-rotated coordinates 0”-X゛Y”Z”.
It is expressed by equation (10) in the figure. When rotated by θ in this manner, the eccentricity/inclination matrix becomes S·Q.

Next, in (#14), the eccentricity/inclination matrix of the next surface of the polygon mirror surface, that is, the front surface of block C is determined. The eccentricity/inclination matrix for the front surface of block C is determined assuming that the absolute position remains unchanged from before the rotation. One method for this will be described below.

First, the coordinate system of the front surface of block C before rotation is 0,'-
A transformation matrix W between X4'Y4'Z,' and the coordinate system 0+XIYlZ+ of the first surface (front surface of block A) is determined. This is shown as equation (11) in FIG. This matrix W does not change even after θ rotation.

Next, the rotated coordinate system 0"'-x'y'" Z゛° and the coordinate system 0 of the first surface. -X, Y, Z, and the transformation matrix U is obtained as shown in equation (12) in FIG. Said (11)
From equation (12), equation (13) 2 in FIG. 12 is obtained. From this, the eccentricity/inclination matrix of the front surface of block C after θ rotation becomes wu-'.

In the above manner, the eccentricity/tilt matrix at the reference position and the eccentricity/tilt matrix at each rotational position are determined.

This matrix becomes coordinate conversion data when converting position coordinates in the virtual optical system to position coordinates in the true coordinate system.

Incidentally, here is a supplementary explanation regarding step (#4) in the above flowchart.

In (#4), the input center coordinates are, for example, (Xc',
Yc'.

Zc'), this is converted into coordinate values (Xc, Yc, Zc) in the coordinate system ○-xyz of the virtual polygon surface, but the three coordinate system codes mentioned above (see Figure 9) The conversion process differs slightly depending on which method you use to input the center coordinates. First, when there is one coordinate system code, the virtual polygon scanning plane is eccentric/(not oblique), so Xc=Xc' −Lp−+ (tp−+ is )Yc
=Yc'Zc=Zc'. When the coordinate system code is 2, the coordinate transformation matrix T is initialized to a unit matrix. Repeat the following (I) (■) from the second surface to the virtual polygon scanning surface (B). (
j=2~P).

(1) Find the coordinate transformation matrix Tj from the (j-1)th plane to the jth plane. This is equation (4) where θ=0, Yo=Z
It can be found by setting o=O. This Tj is expressed as (14) in Figure 12.
Shown in 2. If the j-th plane is eccentric/(approximately oblique), then T j -D j -T j where t, -1 is the distance between the (j-1) plane and the j plane, Dj
is the eccentricity/tilt matrix of the j-plane.

(n) Update coordinate transformation matrix T (T-Tj・T)
do.

Next, using this matrix T, (Xc, Yc,
Zc) is determined as shown in (I5) 2 in FIG.

Finally, if the coordinate system code is 3, first of all (
16) Find the locus type transformation matrix T by (-ω) rotation as shown in the equation. This equation (16) is θ--ω, Xo=Yo=Z in the matrix of equation (4).

It can be found by substituting =0. Using the coordinate transformation matrix T obtained in this way, (Xc, Yc, Zc) is calculated using equation (17) in FIG. FIG. 11 shows a flowchart including the cases of each of the three coordinate system codes mentioned above.

Although the data structure in the case where the polygon surface is eccentric/tilted has been described above, there are cases where it is desired to examine the characteristics in a state where the polygon surface is not eccentric/tilted. For example, this is the case when it is desired to evaluate the pupil aberration of an optical system. In a decentered optical system [for example, Fig. 3 (b)], the optical axis after folding moves due to rotation (the reference moves), so there is little point in evaluating longitudinal aberrations. should be evaluated in the system. Therefore, there may be cases where it is desired to return the configuration of a data system such as an eccentricity/inclination matrix once created to the configuration of the virtual optical system.

In that case, function PF11 shown in FIG. 9 may be selected.

FIG. 13 shows a flowchart that takes such a function into consideration. After selecting a key in (1101), in (1101)
In step 02), it is checked whether the system is in the folded state B (eccentric/inclined state), and if NO, the process goes to (Q), after which the process continues to the flow shown in FIG. 10 described above. (#.

If YES in 2), the eccentricity/inclination matrix of the polygon mirror surface and the eccentricity/(kJl oblique matrix of the front surface of the bronc C) are both returned to unit matrices at (+103).

This restores the system to its non-eccentric/untilted state.

Next, it is checked whether the key pressed at (+104) is PFII, and if YES, the process ends; if NO, (
Proceed from Q) to the flow shown in Figure 10.

In this example, by adjusting the reference angle and the direction cosine of the rotation axis in the input data, a polygon whose scanning plane (B) and rotation axis (18) are tilted non-parallel as shown in FIG. Mirrors can be set. This is because the scanning plane is mainly determined by the reference reflection angle ω, and the rotation axis (
1 day) is determined by the direction cosine. Also, by changing the cosine in the direction of the rotational axis in the same way, Figure 3 (
As shown in FIG. 4(b) and FIG. 4(b), the installation direction of the polygon mirror (1) and its scanning direction can be changed. In this way, the present invention not only allows data on an eccentric/inclined optical system to be established from data on a virtual optical system, but also enables setting of scanning members of various shapes according to the values of the input data, as well as the arrangement and scanning direction of the scanning member. This is convenient because it can be set arbitrarily. The apparatus shown in FIG. 1 can be constructed by connecting an external storage device (14) containing a program that performs the above operations to an existing computer.

Note that after establishing the data of the eccentric/inclined scanning system using the device of the present invention, it is possible to perform, for example, ray tracing calculations depending on the intention of the optical system designer, but these ray tracing and other processes may be performed separately. This is done according to the program.

However, data establishment of the scanning optical system and processing such as ray tracing can also be performed as a series of systems. At that time, the external storage device (14) may be replaced with an external device containing a program dedicated to ray tracing and ray depiction, or the above-described program for configuring the present invention and the ray tracing program may be stored in the same external storage device. It is also possible to have it built-in.

Effects of the Invention According to the present invention, once the necessary data is input, the coordinate transformation data of the scanning optical system is established by the functional means set in the CPU based on the information in the external storage device. This is extremely advantageous when designing optical systems.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the configuration of a data creation device of the present invention, and FIG. 2 is a diagram showing an outline of a scanning optical system using a polygon mirror. FIG. 3 is a diagram showing an example of a scanning optical system having a polygon mirror to which the present invention is applied, and FIG. 4 is a diagram showing another example. FIG. 5 is a diagram showing the reference position and rotated position of the polygon mirror. FIG. 6 is a diagram showing a modification of FIG. 4. FIG. 7 is a diagram for explaining the relationship between the eccentric/inclined coordinate system and the original coordinate system. FIG. 8 is an explanatory diagram for calculating coordinate transformation data of a block behind a polygon mirror. FIG. 9 is a diagram showing a table displayed on the screen that serves as a guideline when inputting data. FIG. 10 is a flowchart of this embodiment, and FIG. 11 is a flowchart showing a part of it in detail. FIG. 12 is a diagram summarizing mathematical formulas used to explain the present invention. FIG. 13 is a flowchart with a function for returning to the virtual optical system. (1)...polygon mirror, (12)...CP
U. (13)...Input means, (14)...External storage device, (16)...First means, (17)...Second means, (18)...Rotating shaft, (B )...
Scanning plane, (ω)...Reference reflection angle, (d)...
・Inscribed circle diameter.

Claims (4)

[Claims] (1) A data creation device for a scanning member whose center of a scanning surface moves by rotation, comprising a CPU, an external storage device,
input means and the C based on the information of the external storage device.
and a functional means set in the PU, and the functional means specifies the scanning member in a virtual optical system assuming that the optical axis of the scanning surface of the scanning member coincides with the optical axis of the input optical system. The information inputted by the input means includes the surface number, the distance from the rotation axis to the scanning surface, the reference reflection angle, the center coordinates, the cosine in the direction of the rotation axis, and the coordinate system code for specifying the center coordinates and the cosine in the direction of the rotation axis. a first step of establishing coordinate transformation data for the scanning plane with the scanning member at a reference position;
means, and second means for establishing coordinate transformation data for the scanning plane at the rotational position of the scanning member based on the data established by the first means and the rotation angle information input by the input means. A scanning optical system data creation device characterized by: (2) The coordinate transformation data is an eccentricity/inclination matrix formed by the product of a rotation matrix regarding the rotation of the scanning member and an origin movement matrix regarding the center of the scanning surface. The data creation device described. (3) The data creation device according to claim 1, wherein the scanning member is a polygon mirror. (4) The data creation device according to claim 1, wherein the scanning member has a single scanning surface.