JPS6027225B2 - Pattern sheet for sensor position adjustment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sensor position adjustment pattern sheet used when positioning a solid-state image sensor such as a CCD with respect to an optical axis of a lens system.

In contrast to the light beam of a lens system, an image sensor such as a CCD has a total of 5 points: the direction of the optical axis (focus) and its inclination, the longitudinal direction of the sensor in a plane perpendicular to the optical axis, the direction perpendicular to the longitudinal direction of the sensor, and its frame. Directional position adjustment is required.

For example, in the solid-state scanning manuscript scanning method used in facsimile machines and the like, as shown in FIG. I'm starting to look down on the statue.

In this case, the original 1 is fed in the direction (A) perpendicular to the line sensor 3 at equal pitches of 4 equal to the 1-bit reading width of the line sensor 3, and the original surface is sequentially scanned by the line sensor 3, so that the entire original surface is scanned. be read.

With respect to the document surface reduced by this lens system 2, as shown in FIG.
8. Optical axis direction (Z) of the lens system 9 and its direction (Z)
It is necessary to adjust in 5 directions. Conventionally, the position adjustment work for the line sensor 3 has been performed by placing a position adjustment pattern sheet on the document surface and monitoring the output of the line sensor that has read each direction adjustment pattern.

An example of a conventional sensor position adjustment pattern sheet is shown in FIG. In FIG. 3, 11 is a striped pattern for focus adjustment, 12 is a horizontal line pattern for adjusting the direction perpendicular to the longitudinal direction of the sensor and its inclination, 13 is a vertical line pattern for adjusting the longitudinal direction of the sensor, and 14 is a pattern sheet.

These patterns shift their positions at each stage of adjustment, resulting in errors in repeated pattern positioning.
This was one of the causes of decreasing sensor position adjustment accuracy.

Furthermore, it was not possible to check two or more types of patterns at the same time, and the checking and correction work took time.

The present invention was invented in view of the above points, and its purpose is to provide a pattern sheet for sensor position adjustment that allows the position of the sensor to be adjusted in five directions without shifting the position of the pattern. .

The feature of the present invention is that three types of patterns for focus adjustment, sensor longitudinal direction adjustment, and sensor longitudinal direction adjustment are combined to form a composite pattern within the same field of view from the sensor surface through the lens system. It is that you are.

Other objects and features of the present invention will become apparent from the following description of embodiments.

FIG. 4 is a pattern diagram of a pattern sheet for sensor position adjustment showing an embodiment of the present invention.

In FIG. 4, 15 is a pattern sheet, 16 is a striped pattern for focus direction (Z direction) adjustment, 17 is a striped pattern for focus direction tilt (Z' direction) adjustment, and 18 is a striped pattern for adjusting focus direction (Z' direction).
is a black strip pattern for sensor longitudinal direction (x direction) adjustment, 19
is the horizontal line pattern for adjusting the direction perpendicular to the sensor longitudinal direction (Y direction),
20 is a horizontal line pattern for adjusting the inclination in the direction perpendicular to the longitudinal direction of the sensor (Y' direction).

The black strip pattern 18 is used for adjusting the longitudinal position of the sensor, as will be described later. The horizontal line patterns 19 and 2 rivers are provided in contact with both sides of the black belt pattern 18, respectively, and the striped patterns 16 and 17 are provided on both sides of the horizontal line patterns 19 and 20 and are provided at some distance apart. , the rope patterns 16 and 17 are divided into a plurality of groups, as shown in the example for 16, and the pitch interval (pitch P) between each group is narrower than the stripe pattern interval P within the group. Each pattern will be explained below using FIGS. 5 to 8. For a large black band pattern 18 as shown in FIG. 5, the output of the sensor 3 becomes a trapezoidal wave 21 as shown in FIG. The range in which the output signal indicates the black pattern level 22 becomes less than half the width of the actual black pattern image. On the other hand, on the focus point, the 6th
The result is a rectangular wave 24 shown in the figure, and the range of black pattern level 2 almost matches the width 23 of the black pattern image.

Therefore, in order to roughly adjust the position of the sensor 3 in the X direction 6 before focus adjustment (Z, Z' directions),
It should be similar to the wide black band pattern 18 shown in FIG. The patterns 16 and 17 for position adjustment in the Z direction 9 and the Z direction 10 correspond to the white pattern reduced by the lens system 2 when the bit 26 of the sensor 3 is on the focus point, as shown in an example in FIG. The black and white striped pattern is such that the width of the stripe 27 and the black pattern image 28 is equal to the width 29 of one bit of the sensor 3.

Further, as shown in FIG. 4, the striped patterns 16 and 17 are each divided into eight groups, and the pitch between each group is narrowed to the extent that the pitch of the patterns is narrower. For X of sensor 3
Even if the position in the direction 6 is shifted, as shown in FIG.
is projected onto a portion of 15/16 or more of the area of the bit 26.

Therefore, using striped patterns 16 and 17, sensor 3
When adjusting the position of the sensor 3 in the Z direction 9 and the Z' direction 10, even if the position of the sensor 3 in the x direction 6 is shifted, the striped pattern 1
A sensor 3 detecting images 27 of white patterns 6 and 17
The fluctuation value of the maximum output voltage value of bit 26 is 1/1 of the maximum value.
Since it is guaranteed to be 16 or less, it is stable in the Z direction 9 and Z
Position adjustment in direction 10 is performed. Furthermore, when checking the position after adjusting the position in the Z direction 9 and the Z' direction 10, the fluctuation width of the output voltage of the sensor 3 due to the phase shift between the striped patterns 16 and 17 and the bit 26 of the sensor 3 is the maximum output voltage. Since it is less than 1/16 of the value, Z direction 9 and Z'
The position detection error in the direction 10 can be kept small, and the sensor 3 and the striped patterns 16 and 17 are not moved.
That is, it is possible to improve the accuracy of position confirmation using a static method.

Next, in the images 19A and 20A of the Y-direction and Y-direction adjusting edge line patterns 19 and 20 shown in FIG.
and satisfies the allowable tilt amount of the bit string 30 in the Y direction (not shown).

Therefore, if the position of the sensor 3 is adjusted so that the horizontal line pattern detection bit detects the horizontal line pattern 19, the position adjustment of the sensor 3 in the Y and Y directions is completed.

Further, by monitoring the output voltage value of the blind line pattern detection bit of the sensor 3, the Y and Y direction positions can also be confirmed. The tangential pattern 19 can also be used for adjustment in the x direction 6. If the sensor 3 is precisely adjusted in the
Since the image 18A of the black belt pattern 18 is projected in focus, the position of the center of the horizontal line pattern 19 and the image of the black belt pattern 18 in the x direction 6 and the center of the sensor 3 in the x direction 6 can be calculated. If they are combined, the adjustment in the X direction 6 is performed. The composite pattern shown in FIG. 4 is a combination of the phase adjustment patterns in each direction as described above based on FIGS. 5 to 8. If the sensor 3 specifies the bits 26 for detecting each pattern of the composite pattern, the position adjustment in each direction becomes possible even if the pattern sheet I5 is fixed. In the explanation of the above embodiment, Z, Z
'The adjustment was made by looking at the change in the output voltage level of the sensor for the white pattern image, but this can also be done by looking at the sensor output for the black pattern image, or by comparing the bit that detects the white pattern image with the adjacent black pattern image. This can also be done by looking at changes in the output voltage difference between adjacent bits of the bit to be detected.

As described above, according to the present invention, since the composite pattern is fixed, it is possible to eliminate the sensor position adjustment error caused by the repeated positioning error of the conventional simple pattern, and improve the adjustment accuracy.

Further, according to the present invention, the position in each direction can be checked statically,
Adjustment reliability is improved. Brief explanation of the drawings Figure 1 is a schematic configuration diagram showing the positional relationship between the document, lens system, and sensor, Figure 2 is an explanatory diagram to explain the sensor position adjustment direction, and Figure 3 is the conventional sensor position. FIG. 4 is a diagram showing an example of a pattern sheet for adjusting the sensor position according to the present invention, and FIGS. 5 to 8 are used to explain FIG. 4. , FIG. 5 is a perspective view showing the positional relationship between the black belt pattern 18, the lens system, and the sensor. FIG. 6 is a diagram showing changes in the black belt pattern reading signal due to deviation in the focus direction of the sensor. FIG. 7 is a diagram showing the sensor bits. FIG. 8 is a diagram showing the positional relationship between the image of the black band pattern, the image of the square line pattern, and the sensor bit.

15... Pattern sheet, 16, 17... Striped pattern,
18...Black obi pattern, 19,20...
・Horizontal line pattern.

Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. In a pattern sheet for sensor position adjustment used when adjusting the position of a solid-state image sensor with respect to the optical axis of a lens system, when placed in the center and projected onto the sensor, the width is wider than the width of 1 bit of the sensor. A black strip pattern for rough adjustment of the longitudinal position of the sensor having a sufficiently large width is provided, and when it is placed in contact with both sides of the black strip pattern and projected onto the sensor, it has a width corresponding to one pitch of the sensor. Horizontal line patterns for finely adjusting the longitudinal position of the sensor and for adjusting the position and inclination in the direction perpendicular to the longitudinal direction of the sensor and having substantially equal widths are provided, and are arranged at positions on both sides of the horizontal line pattern and away from the horizontal line pattern, When projected onto the
It is divided into n groups consisting of multiple vertical line patterns each having a width of 1 bit, and the interval between each group is set to 1/n.
A striped pattern for position and inclination adjustment in the focus direction that is shifted by a pitch is provided, and the black strip pattern, the horizontal line pattern, and the striped pattern are placed within the same field of view from the sensor through the lens system, and the black strip pattern is placed above the lens system. A pattern sheet for sensor position adjustment, characterized in that the striped pattern is positioned at the center of the same field of view and at both ends of the same field of view.