JP3159785B2 - Automatic adjustment device for optical reading unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically adjusting an optical reading unit.

[0002]

2. Description of the Related Art A conventional optical reading unit is adjusted by reading an optical chart with an image sensor, drawing a focus shift and a position shift of the image sensor on an oscilloscope as an output signal waveform, and checking an operator's waveform while checking this waveform. Adjustments are made by hand.

[0003]

However, the position adjustment of the image sensor includes focus adjustment, tilt adjustment, up / down / left / right shift adjustment, and rotation adjustment, and all adjustments must be within a specified range. However, in the above-described conventional method, there is a problem that the skill of an operator is required, and a long time is required for the adjustment because the positional shift occurs due to the fixation to the image sensor substrate after the position adjustment.

The present invention provides a quick and accurate image sensor.
Automatic adjustment of the optical reading unit for precise position adjustment
Provide equipment. Also, there is provided an automatic adjustment device of an optical reading unit capable of quick position adjustment in consideration of a position shift in fixing to an image sensor substrate after the position adjustment.

[0005]

In order to solve this problem, an automatic adjusting apparatus for an optical reading unit according to the present invention comprises a lens and an image sensor as basic components . Rank
This is an automatic adjustment device of the optical reading unit that adjusts the position, and shifts the position of the optical chart, which is the reference for position adjustment.
Moving means for moving, and a position moved by the moving means
The optical chart is read by the image sensor.
Based on the output signal of the image sensor.
Focus position detecting means for detecting the focus position of the lens;
The optical chart at the reference position is transferred to the image sensor.
Read thereby, varying calculating means for sending a control signal calculated by the positional deviation amount of the image sensor from an output signal of the image sensor, the position relative to the optical reading unit of the image sensor based on the control signal
A further driving means, is changed by the driving means located
Having a fixing means for fixing said image sensor
It is characterized by the following .

Here, the optical chart is further illuminated.
Lighting means. Also, focus, tilt, left and right,
Up and down and rotation position can be adjusted . The optical chart has a pattern for detecting a position shift in focus, tilt, left / right, up / down, and rotation directions, and the pattern of each position shift detection unit is light transmissive. Further, the illumination means has a diffusion plate for obtaining uniform illumination light. In addition, the lighting
The means transmits and illuminates the optical chart. In addition,
The driving unit controls the image sensor by the fixing unit.
The optical reading unit of the image sensor is adjusted so that the optimum position is obtained after fixing in consideration of the amount of displacement at the time of fixing.
Change the position relative to the unit. Further, the driving means includes:
It has three image sensor board holding pins and pins for performing initial position adjustment by abutting from the rear of the image sensor board. Also, the gripping pin is in a focus adjusting direction.
Slippery surface structure. Further, the fixing means,
It is possible to repeat the fixing operation and the releasing operation independently for each fixing point. Further, the fixing means is fixed at each of the fixing points.
The torque is variable.

[0007]

According to the present invention, an optical chart image serving as an adjustment reference is read as an image sensor output signal of an optical reading unit, and the focus, tilt, up / down, left / right, rotation, etc. of the optical reading unit are adjusted from this signal. detecting the position of the required image sensor, when the proper alignment of the image sensor to the proper direction, the reference position adjustment
Quick and accurate position adjustment of the image sensor by providing a moving means for moving the position of the optical chart
It can be performed.

[0008]

FIG. 1 is a block diagram showing the configuration of an automatic adjusting device for an optical reading unit according to an embodiment of the present invention, and FIG. 2 is a structural explanatory view of the automatic adjusting device.

1 is an image sensor, 2 is an image sensor substrate, 3 is a selfoc lens array, 4 is an image sensor position setting bracket, 5 is an optical reading unit, 6 is an image sensor position setting bracket fixing screw, and 7 is an image sensor. A board fixing screw, 8a is an image sensor position setting bracket screw driver, 8b is an image sensor board fixing screw driver, 9 is an optical chart, 10a is a side board holding pin,
10b is an upper substrate holding pin, 11a is a horizontal position adjustment stage, 11b is a focus position adjustment stage, 11c is a rotation position adjustment stage, 11d is a vertical position adjustment stage, 1
1e is a tilt position adjustment stage, 12 is an image sensor initial position setting pin, 13 is a light source, 14 is a diffusion plate, 15 is an optical rail, 16 is a downward contact pin, 17 is a sliding piece, 20 is a small computer, 21 is Image sensor signal, 2
2 is a drive instruction signal, 23 is a position adjustment stage (11a,
11b, 11c, 11d, 11e), grip claws (10
a, 10b) and screwing drivers (8a, 8b).

The structure of the optical reading unit 5 is such that the image sensor 1 is soldered to the image sensor substrate 2, and the image sensor substrate 2 is fixed to the image sensor position setting bracket 4 with image sensor substrate fixing screws 7,
The image sensor position setting bracket 4 is fixed to the optical reading unit 5 with an image sensor position setting bracket fixing screw 6. The focus and tilt directions are set by image sensor position setting metal fixing screws 6, and the left, right, up and down directions are set by image sensor substrate fixing screws 7. The SELFOC lens array 3 is fixed to the optical reading unit 5, and the optical adjustment is performed by adjusting the position of the image sensor 1.

The mounting position of the optical reading unit 5 is set by an optical rail 15, a lower abutment pin 16, and a sliding piece 17, and is fixed to the automatic adjusting device by an optical reading unit clamping mechanism (not shown). You. The position of the optical chart 9 is set to the position of the original for the optical reading unit 5, and the light source 13 and the diffusion plate 1 are set.
4, and the transmitted illumination is made more uniform. In order to prevent the optical reading unit 5 from picking up unevenness on the surface of the diffusion plate 14, the diffusion plate 14 is set at a position outside the depth of focus of the optical reading unit 5 and is not brought into close contact with the optical chart 9.

The signal 21 of the image sensor 1 is analog /
The digitally converted data is stored in a memory in the small computer 20 via a high-speed buffer memory. The small computer 20 performs digital arithmetic processing on the image sensor signal 21,
The amount of displacement in each adjustment direction is calculated. Small computer 20
The drive signal 2 is sent to the drive mechanism 23 of each position adjustment stage, gripping claw, and screw tightening driver based on the amount of the position shift.
2 is output.

The position of the image sensor 1 is adjusted by gripping both side surfaces of the image sensor substrate 2 with the side substrate gripping pins 10a, supporting the upper surface with the substrate gripping pins 10b, adjusting the left and right positions with the left and right position adjustment stages 11a, and focusing. The position is adjusted by the focus position adjustment stage 11b, the rotation position is adjusted by the rotation position adjustment stage 11c, the vertical position is adjusted by the vertical position adjustment stage 11d, and the tilt position is adjusted by the tilt position adjustment stage 11e. Rotational position adjustment stage 11c
And the tilt position adjustment stage 11e are the image sensor 1
Are arranged so that the center of the rotation becomes the center of rotation, thereby reducing inter-axis interference during adjustment.

Image sensor position setting fitting fixing screw driver 8a and image sensor board fixing screw driver 8b
Are driven to rotate by a motor (not shown). The driver drive torque is controlled by switching the current flowing to the driver drive motor. The tips of the drivers 8a and 8b have a structure as shown in FIG.
2 is a flexible joint, 803 is an angle restoration rubber,
Reference numeral 804 denotes a driver bit pressing spring, and 805 denotes a driver driving shaft. The driver bit 801 can move freely in the swinging direction by providing the flexible joint 802, and can move freely in the expansion and contraction direction by the driver bit pressing spring 804. The posture of the driver bit 801 in the normal state is the angle restoring rubber 8
03 is coaxial with the driver drive shaft 805, and is in the state of being most protruded by the driver bit pressing spring 804. It can move with a weak force in these swinging and telescopic directions.

An adjusting method in the optical reading unit automatic adjusting device having the above configuration will be described with reference to an adjusting procedure in FIG.

<Step 4a> —Attaching Optical Read Unit First, the optical read unit 5 to be adjusted is set along the optical rail 15 and automatic adjustment is started. The optical reading unit 5 is clamped by an optical reading unit clamping mechanism (not shown) and fixed to the automatic adjusting device. At this time, the optical reading unit 5 includes the optical rail 15 and the downward contact pin 16.
And the sliding piece 17 (not shown).

<Step 4b>-Initial Stage Position Setting At the same time as the optical reading unit 5 is clamped, each of the adjustment stages 11a to 11b is moved to a predetermined initial position. This initial position is determined by origin search performed after the power is turned on. The origin is determined by moving each stage to a limit switch (not shown) and returning the stage position by the number of pulses determined based on the position as the origin.

<Step 4c> -Gripping of Image Sensor Board First, the image sensor position setting bracket driver 8a is lowered, and the tip of the driver is pressed against the head of the image sensor position setting bracket fixing screw 6. In this state, since the rotation angles of the screw head 6 and the end of the driver wire do not match, the tip of the image sensor position setting bracket fixing screw driver 8a cannot enter the screw head 6. Then, by driving a driver motor (not shown) with a small current, the driver is slowly rotated rightward with a small torque.
Since a hexagonal screw is used here, in principle, the angle between the image sensor position setting metal fixing screw 6 and the tip of the driver matches while the driver is rotated by 60 degrees, and the image sensor position setting metal fixing screw fixing screw driver 8a Tip of the screw enters the screw head. Actually, it is rotated to the right by 60 degrees or more in anticipation of play such as a flexible joint. Once the image sensor position setting bracket fixing screw driver 8a is set, the motor rotating with a weak torque does not rotate any more. This is because the temporarily fixed image sensor position setting metal fixing screw cannot be further tightened with a weak torque. The motor rotation angle is monitored by a rotary encoder (not shown) attached to the motor shaft. When the rotary encoder stops rotating any more, the motor stops, that is, the tip of the image sensor position setting bracket fixing screw driver 8a is securely attached to the screw head. To be set.

After the image sensor position setting metal fixing screw driver 8a is securely set, the motor current is switched to the maximum, and the image sensor position setting metal fixing screw driver 8a is rotated counterclockwise with a strong driver torque to fix the image sensor position setting metal fixing. Loosen screw 6. In this manner, the image sensor position setting bracket fixing screw 6 is loosened, and the focus position adjustment stage 11b moves forward in a state where the image sensor substrate 2 can freely move in the focus direction, and the image sensor initial position setting pin 12 is placed on the back side of the image sensor substrate 2. Strike. The image sensor initial position setting pins 12 are made of an insulator, and do not electrically interfere with the image sensor substrate 2. A sponge (not shown) is provided between the entire surface of the image sensor 1 and the optical reading unit 5, and the sponge surely presses the image sensor substrate 2 against the image sensor initial position setting pin 12, and the temporary fixing posture. First, the focus position of the image sensor substrate 2 is substantially mechanically positioned.

Next, the image sensor board fixing screw driver 8b moves forward and presses the tip of the driver against the image sensor board fixing screw 7. Similar to the setting of the image sensor position setting metal fixing screw driver 8a, the image sensor substrate fixing screw driver 8b
Is rotated to the right to set the screw on the screw head. After confirming that the rotary encoder is securely set, the motor drive current is switched to the maximum, the driver 8b is rotated to the left, and the image sensor board fixing screw 7 is loosened.

In a state where the image sensor substrate fixing screw 7 is loosened and the image sensor substrate 2 can freely move in the vertical, horizontal and rotational directions, the image sensor substrate 2 is provided on the side of the image sensor substrate by the side substrate holding pins 10a. Not to grip the gripper. Thereafter, the image sensor substrate 2 is gripped at three points by gripping the substrate with the upper substrate gripping pins 10b. The side substrate holding portion (not shown) is cut into an oval shape so as not to slip even when the force of the upper substrate holding pin is applied. A large number of fine screw-shaped grooves are provided on the surface of the side substrate gripping pin 10a and the upper substrate gripping pin 10b in contact with the substrate, and the image sensor substrate is used when the focus direction adjustment is performed by the focus position adjustment stage 11b. The grip section 2 is prevented from slipping.

However, the attitude of the image sensor board 2 here does not match the attitude when the board is released by screwing. This is because the substrate is in the posture when the screws are loosened. Thus, the substrate is released once all the screws are tightened, and the substrate is gripped again in that posture.

First, the image sensor position fixing screw 6 is tightened. The image sensor position fixing screw driver 8a is rotated clockwise with a small torque and tightened. When the tightening with the weak torque is completed, the screw tightening motor (not shown) does not rotate any more. The rotation angle is monitored by a rotary encoder (not shown) to detect the completion of the tightening. After that, the torque is switched to a sufficiently large torque and retightening is performed. When the driver is rotated clockwise, the tip of the driver bit and the head of the screw remain biting. Therefore, after retightening, the driver is slightly counterclockwise rotated with a weak torque to eliminate biting.

The image sensor board fixing screw 8b is similarly tightened. Then, with the image sensor board 2 fixed, the side board holding pins 8a and the upper board holding pins 8b are released. Then, the focus position adjustment stage is slightly retracted so that the image sensor initial position setting pins 12 do not contact the image sensor substrate 2. Then, while keeping the posture of the image sensor substrate 2 in the same state as when the substrate is released, the side substrate gripping pin 10a and the upper substrate gripping pin 10b
Then, the substrate is gripped again.

<Step 4d>-Coarse adjustment in up, down, left, right, and rotation directions Position adjustment is performed from coarse adjustment in up, down, left, right, and rotation directions. First, the image sensor board fixing screw driver 8b is rotated counterclockwise with strong torque to loosen the image sensor board fixing screw 7,
Left / right position adjustment stage 11a, up / down position adjustment stage 1
1d, the image sensor substrate 2 is made to move according to the movement of the rotation position adjustment stage 11c.

Next, the output signal 21 of the image sensor 1 is read into the small computer 20, and the displacement amount is calculated from the signal. An image of the pattern of the optical chart 9 is formed on the image sensor 1, and a light amount signal on a light receiving surface of the image sensor 1 corresponding to a shift in each direction is obtained as an image sensor signal waveform. The optical chart 9 is configured as shown in FIG. 5A, and the image sensor signal 21 obtained here is obtained.
In the waveform of (a), a portion where light is applied to the image sensor 1 becomes a large light amount signal, and a portion where light is not applied has a low signal level, as shown in FIG. 5 (b) to FIG. 5 (f). Waveform. In capturing the image sensor signal 21, the signal is captured a plurality of times and averaged to reduce the noise level.

5 (b) to FIG. 5 (f).
The peak portions of 1, p2, p3, p4, p5, p6, and p7 correspond to the patterns 901, 902, 903, 904, 905, 906, respectively, of the optical chart shown in FIG.
907. FIG. 5B is a waveform when the best position is set in each of the directions of focus, tilt, up / down, left / right, and rotation. FIG. 5C shows a waveform when the focus and the tilt direction are not aligned. FIG. 5D shows the image sensor 1 which is in focus and in the tilting direction.
Is the waveform when it is shifted clockwise to the right and upward.
FIG. 5E shows a waveform when the image sensor 1 is shifted upward and clockwise. FIG. 5F shows a waveform when the image sensor 1 is shifted downward and clockwise.

In order to detect the amount of displacement in each direction from the image sensor signal 21, it is necessary to first find out which part of the optical chart corresponds to each peak of the obtained image signal 21. Therefore, the center of gravity of the light amount is obtained in a certain area near the center of the image sensor signal 21. The data area used for calculating the center of gravity at this time is an area in which only the central slit 904 enters even if the image sensor 1 in the initial state has the largest lateral displacement. Therefore, the center of gravity of the light quantity obtained here becomes the center of gravity of the center peak waveform p4 by the center slit 904. In order to further improve the accuracy of the center of gravity, the light amount center of gravity is obtained by narrowing down the data in the vicinity of the center peak waveform p4 obtained here, and is set as the position of the center slit 904 with respect to the image sensor 1. Hereinafter, the peak waveform p for each of the chart parts 901 to 907
Where 1 to p7 are in the image sensor signal 21 is
It is obtained by the relative position from the position of the center slit 904 obtained above.

Until now, the dark signal of the image sensor signal 21 has been ignored. However, subsequent calculations are:
The average of the pixel signals corresponding to the dark portions of the optical chart is defined as a dark signal, and a shift in each direction is calculated using the image sensor signal 21 obtained by subtracting the dark signal from the original signal of the average signal obtained by taking the plural times. .

Left-right position: center slit peak waveform p4 with respect to center pixel position n ₀ (pixel) of image sensor 1
The horizontal position x (μm) of the image sensor 1 from the barycenter pixel position n ₄ (pixel) is obtained by x = d · (n ₄ −n ₀ ). Here, d (μm) is the image sensor pixel pitch. When the position in the left-right direction is matched, the peak signal p4 is located at the center of the image sensor signal 21 as shown in FIG. 5B, so the left-right position is zero, but the image sensor 1 is shifted in the left-right direction. 5, the center slit peak waveform p4 is shifted from the center of the image sensor signal 21 as shown in FIG.

Vertical position: The vertical reference position is determined by the signal p by the triangular portions 902, 903, 905, and 906.
2, p3, p5 and p6 are almost eliminated.
When the image sensor 1 is shifted upward with respect to this reference, the signals p2 and p6 of the downward triangular portions 902 and 906 become large, and the signals p3 and p5 of the upward triangular portions 903 and 905 become zero. An image sensor signal waveform such as e is obtained. Conversely, when the image sensor 1 shifts downward, the signals p2 and p6 of the downward triangle units 902 and 906 become zero, and the signals p3 and p5 of the upward triangle units 903 and 905.
Becomes large, and a waveform like f in FIG. 5 is obtained. Since the shapes of the triangular portions 902, 903, 905, and 906 are tapered, the amount of light increases in proportion to the amount of vertical displacement.

Therefore, the optical chart triangular portions 902 and 90
3 as an example, the peak waveform p2 of the downward triangle 902
Let i _{2 be} the light amount of the peak waveform p3 of the upward triangular portion 903 and i ₃ be the light amount of
₂₃ (μm) becomes y ₂₃ = y ₀ (i ₂ −i ₃ ) / i _o . Here, i ₀ is a unit light amount, and y ₀ (μm) is a vertical shift amount per unit light amount. The light amount of each peak waveform is obtained as the sum of the light amounts of the pixels near the peak waveform. Here, the light amounts i ₁ , i of the slit portions 901, 904, 907 are set as i _0.
4, the average of i _7, with _{i 0 = (i 1 + i} 4 + i 7) / 3, to offset changes in light amount due to light source intensity change with the use of the width of the slit portion 901,904,907 as y _0.

The same applies to the triangular portions 905 and 906 of the optical chart.
Vertical displacement y detected₅₆Is y₅₆= Y₀ (I₆ 
−i_Five ) / I₀ Becomes Where i₆ Is the downward triangle 9
06, the light quantity of the peak waveform p6, i_Five Is the upward triangle 90
5 is the light amount of the peak waveform p5. Therefore, image
The vertical position y (μm) of the sensor 1 is the optical chart triangle.
Vertical position y in parts 902 and 903_{twenty three}And the triangle 905,
Vertical position y at 906 ₅₆From the average of y = (y_{twenty three}+
y₅₆) / 2.

Rotation direction position... The rotation direction position θ (rad) of the image sensor 1 is determined by the vertical position y ₂₃ and the triangular portions 905 and 906 in the optical chart triangular portions 902 and 903 which are intermediate results when the vertical position is obtained. Vertical position y ₅₆
From the ^{difference, θ = tan -1 ((y} 56 -y 23) / d 1) ≒ (y 56 -
y ₂₃ ) / d ₁ Here, d ₁ is a distance between the center of the downward triangle 902 and the upward triangle 903 on the left side of the optical chart, and the downward triangle 906 and the upward triangle 9 on the right.
This is the interval (μm) to the center position 05.

A drive instruction is issued to the left / right position adjustment stage 11a only for the left / right position x obtained above, and the left / right position correction is performed. At the same time, a drive instruction is issued to the vertical position adjustment stage 11d for the vertical position y, and to the rotational position adjustment stage 11c for the rotational direction θ, and the respective positions are corrected. Here, the left / right position adjustment stage 11a and the up / down position adjustment stage 11b are perpendicular to each other, the rotation center of the rotation position adjustment stage 11c is substantially coincident with the center of the image sensor 1, and the respective adjustment axes do not interfere with each other. .

<Step 4e> -Is the adjustment standard? Because the center of the image sensor 1 and the rotation center of the rotation position adjustment stage 11c are not completely aligned or due to a measurement error, it may not be possible to adjust the position within sufficient positional accuracy by performing the position adjustment once. Therefore, the signal 21 of the image sensor 1 is read, the amount of displacement is calculated, and the position adjustment is repeated until the required position accuracy is obtained. If the deviation is within the required position accuracy at the time of calculation,
The rotation direction coarse adjustment is completed, and the process proceeds to the next adjustment procedure. However, if the number of repetitions is equal to or greater than the specified number, the adjustment is impossible and the process ends.

After the coarse adjustment in the vertical, horizontal, and rotational directions is completed, the screw 7 for fixing the image sensor substrate is tightened. From the difference between the image sensor position in the up / down, left / right, and rotation directions after screwing and the image sensor position before screwing, position shifts in the up / down, left / right, and rotation directions caused by the screw tightening are determined. Used for fine adjustment of left and right, rotation direction.

<Step 4f> -Adjustment of Focus and Tilt Direction To adjust the focus and tilt direction, first, the image sensor position setting bracket fixing screw 6 is loosened, and the image sensor substrate 2 and the image sensor position setting bracket 4 are integrated. Make it movable in the focus direction.

The focus is detected at the slits 901 904 907 of the optical chart. When the camera is in focus and tilt, all the peak waveforms of the image sensor signal 21 are sharp, such as the peak waveforms p1, p4, and p7 in FIG. However, when the image is out of focus, the waveform becomes dull and spread like the peak waveforms p1, p4, and p7 in FIG. 5C. FIG. 5C shows a waveform in the case where there is also a shift in the tilt direction. The image sensor 1 shows an image sensor signal when the focus shift on the slit 901 side is large and the slit 907 side is smaller than that. . Therefore, the peak waveform p1 of the slit 901 is a waveform that is more dull and spread than the peak waveform p7 of the slit 907. Paying attention to the peak waveform of the slit portion, it can be seen that the light amount of the entire peak is concentrated at the center when the object is in focus. Therefore, this is defined as the degree of focus (degree of focus).

As in the calculation of the degree of focus, the signal 21 of the image sensor 1 is read into the small computer 20, and the degree of focus is calculated from the signal, as in the case of calculating the position in the vertical, horizontal, and rotational directions. First, the image sensor signal 21 is fetched and averaged a plurality of times to obtain an image sensor signal 21 with a reduced noise level. In order to detect the degree of focusing from this, it is necessary to first find out which part of the optical chart corresponds to each peak of the obtained image sensor signal 21. Therefore, similarly to the case of calculating the displacement in the vertical, horizontal, and rotational directions, the center of the light quantity of the peak waveform p4 of the central slit 904 is determined. Thereafter, where the peak waveforms p1 and p7 for the chart slit portions 901 and 907 are located in the image sensor signal 21 is determined by the relative position from the position of the central slit 904 obtained above. Further, using the image sensor signal 21 obtained by subtracting the dark signal from the original signal of the average signal of the above-described multiple-time signal taking as an average of the pixel signals corresponding to the dark portion of the optical chart as a dark signal, each slit portion 901, 904, The degree of focus at 907 is obtained.

Each of the slit portions 901, 904, 90
7 also has a width corresponding to one pixel of the image sensor. When the focus is ideally focused, the slit light forms an image on one pixel or over two pixels of the image sensor. Taking an example of the slit portion 901, the degree of focus u ₁ at this position
Is determined by u ₁ = j ₁ / i _1, which is the ratio of the light amount j ₁ of the central two pixels to the light amount i ₁ of the entire peak. Focus degree u
_The value 1 becomes the maximum value 1 when the subject is in focus, and the value is similarly reduced when the subject is out of focus before or after the subject is out of focus.

The degree of focus u of the slit section 904_Four And slip
Degree of focus u of G part 907₇ Similarly, u_Four = J_Four / I
_Four , U₇ = J₇ / I₇ Asking. Where i_Four Is
The light amount of the entire peak waveform p4 of the slit portion 904, j_Four Is
Light amount of two pixels at the center of the peak waveform of the slit portion 904, i₇ 
Is the total light amount of the peak waveform p7 of the slit portion 907, j
₇ Is the light amount of the two pixels at the center of the peak waveform of the slit portion 907.
is there.

The above-mentioned degree of focus is measured at several points near the position where the focus is best, and the best position is obtained from the focus characteristics. First, the focus position adjustment stage 11b is driven to the first focus degree measurement position, and the image sensor 1 is moved in the focus direction. However, because the stage has backlash, when the stage is stopped while the stage is moving forward and when the stage is stopped while moving backward, even if the command value instructed by the small computer 20 is the same, the stage stops by the amount of the backlash. The position is different. Therefore, when it is desired to stop the position adjustment stage with high accuracy, only the stop is performed while the stage is moving forward or only when the stage is moving backward. Here, it will be stopped while the stage is moving forward. Therefore, here, when the focus position adjustment stage 11b is driven to stop at a desired position, and when the stop position is ahead of the present, the command value corresponding to the distance is simply transmitted from the small computer 20 to the focus position adjustment stage 11b. Should be given to Conversely, when the target position is behind the current position, a command value to move the target position to the rear by a distance larger than the backlash by a sufficient amount in addition to the distance to the target position is sent to the focus position adjustment stage 11b, and then to the target position. Is sent to the focus position adjusting stage 11b, so that the stage always stops while the stage is moving forward.

After the image sensor has moved to the measurement position,
The optical chart slit portions 901, 904,
The in-focus degree 907 is calculated. FIG. 6 shows characteristics when the degree of focusing is measured at nine steps (9 points) before and after the focal position. The measured values are indicated by black dots, and the solid line is the approximate curve. When the camera is in focus, the signal of the slit portion has a sharp peak waveform as shown in FIG. 6B, and the degree of focus approaches one. On the other hand, at the out-of-focus position, the slit image has a widened waveform as shown in FIGS. 6A and 6C, so that the degree of focusing has a small value. In the vicinity of the focal point, this characteristic curve is almost symmetrical and can be regarded as a quadratic curve. Therefore, a secondary approximation curve is obtained from the measured values, and the center of the approximation curve is set as the position where the focus is best.

However, if the focus position deviation from the center of the focus degree measurement range is large, the accuracy of the calculation of the focus position is deteriorated. Therefore, if the center of the calculated approximate curve is ahead of the center of the measurement range by more than a half-step interval of the focus position measurement, it advances one more step and measures the degree of focus additionally. Using the nine measured values including this measured value, the focal position is calculated again from the approximate curve. If the calculated focal position is still more than half a step forward from the center of the measurement range, the above procedure is repeated. Repeat the additional measurement of the degree of focus. Conversely, if the center of the calculated approximate curve is located at least one half-step interval away from the center of the measurement range at the focus position measurement, the focus degree is additionally measured at a position one step back from the measurement start position. The focal position is calculated again from the approximate curve using the nine measured values including this measured value, and if the calculated focal position is more than half a step interval behind the center of the measurement range, it is further retracted by one step. Then, the additional measurement of the degree of focus is repeated according to the above procedure.

According to the above procedure, the characteristic curve of the degree of focusing finally measured has a distance between the center of the curve and the center of the measuring range substantially equal to or less than the half step interval of the focusing position measurement as shown in FIG. Calculation errors can be reduced.

Here, taking the optical chart slit section 901 as an example, first, a focusing degree characteristic curve at this position is represented by a quadratic curve u ₁ (t), and u ₁ (t) = a ₁ t ² + b ₁ t + c. Approximate by ₁ . Here, t is the sensor position in the focus direction, a
₁ , b ₁ and c ₁ are coefficients of the quadratic curve, and can be obtained from the measured values by the least square method. Then the slit 9
Since the focal position z ₁ at 01 is the center of the quadratic curve, z ₁ =
-B ₁ / (2a ₁ ).

Similarly, the focal positions z ₄ ,
The focal position z ₇ of the slit portion 907 is z ₄ = −b ₄ /
(2a ₄ ), z ₇ = −b ₇ / (2a ₇ ) Here, a ₄ and b ₄ are approximate expressions of the focusing degree characteristic curve at the slit portion 904, coefficients of u ₄ (t) = a ₄ t ² + b ₄ t + c ₄ , and a ₇ and b ₇ are coefficients at the slit portion 907. approximate expression of focus level characteristic curve, a coefficient of _{u 7 (t) = a 7} t 2 + b 7 t + c 7.

The focus position z of the image sensor 1 is determined by the focal position z of each of the slit portions 901, 904 and 907.
_1, z _4, the average of _{z 7, z = (z 1} + z 4 + z 7) / 3
The tilt position φ is the focal position z of the slit portion 901
_From the difference between ₁ and the focal position z ₇ of the slit portion 907, φ =
tan ^-1 ((z ₁ -z ₇ ) / d ₂ ) ≒ (z ₁ -z ₇ ) / d ₂
Is calculated as Here, d ₂ is the interval between the slit 901 and the slit 907.

When the focus position and the tilt position are calculated by the above procedure, the focus position adjustment stage is at the focus position measurement point at the frontmost position or at the focus position measurement point at the rearmost position. Then, the focus position adjustment stage is driven to the obtained focus position, and the tilt position adjustment stage is driven to the tilt position. The center of rotation of the tilt position adjustment stage 11e is made substantially coincident with the center of the image sensor 1 so as not to interfere with other adjustment axes.

<Step 4g> —Is the adjustment standard? Here, if the detected focus position and the tilt position are within the adjustment standard, the process proceeds to the next adjustment procedure. If not, the focus degree is measured again, and the focus position and the tilt position are calculated and adjusted again. . However, in the second and subsequent focusing degree measurement ranges, measurement is performed with the focus position calculated last time as the center. If the focus adjustment does not fall within the adjustment specification even after the prescribed number of times, the adjustment is impossible and the process ends.

After the focus position and the tilt position can be adjusted within the standard, the image sensor position setting metal fixing screw 6 is tightened. Thereafter, the screw is kept tightened, so that the screwdriver 8a for fixing the image sensor position setting bracket rises and the driver is separated from the head of the screw.

<Step 4h> Position Adjustment in Up / Down, Left / Right, and Rotation Directions First, in order to perform position adjustment in the up / down, left and right, and rotation directions, the image sensor substrate fixing screws 7 are loosened. Then, as in the case of coarse adjustment in the vertical, horizontal, and rotational directions, the image sensor signal 21 is read, and the positional deviation in the vertical, horizontal, and rotational directions is calculated. Here, taking into account the amount of deviation due to screw tightening that has been measured during screw tightening after coarse adjustment in the vertical, horizontal, and rotational directions, the image sensor position of the screw tightening value is exactly the adjustment target position. Then, a stage drive instruction in each direction is issued. The left-right direction indication amount x _V , the vertical direction indication amount y _V , and the rotation direction indication amount θ _V are x, y, θ of the detected current position, respectively, and the deviation amount at the time of screw tightening measured during the coarse adjustment. Are x _d y _d and θ _d respectively, x _V = x−x _d , y _V = y−y _d , θ _V = θ−
the θ _d. The stage is driven by the left-right direction amount x _V , the vertical direction amount y _V , and the rotation direction amount θ _V.
Tighten the image sensor board fixing screw 7. Since the positional deviation at the time of screw tightening has reproducibility, it is effective to adjust the position in consideration of the deviation at the time of screw tightening.

In the fine adjustment in the up / down, left / right, and rotation directions, the position of the image sensor is detected while the image sensor substrate 2 is released. First, the image sensor board fixing screw driver 8b moves backward and separates from the screw head. Then, the side board holding pin 10a holding the image sensor board 2 and the upper board holding pin 10b are released.
Further, in order to remove and reposition the entire optical reading unit caused by the screw tightening, the optical reading unit clamp mechanism (not shown) is once released and gripped again. In this state, the image sensor signal 21 is fetched, and the image sensor position shift amount in the vertical, horizontal, and rotational directions is calculated. If this is within the standard, the process proceeds to the next adjustment procedure. The image sensor substrate 2 is gripped by the side grip pins 10a and the upper grip pins 10b, and the image sensor substrate fixing screw driver 8b moves forward to insert the driver tip into the screw head.

At this time, the angle of the driver is the same as the angle of the screw head because the angle at the time when the driver was previously pulled out is preserved. Therefore, the clockwise rotation with a small torque, which is performed in the above-described driver insertion procedure, is not necessary here. Then, the image sensor substrate fixing screw driver 8b is rotated counterclockwise with a strong torque to loosen the image sensor substrate fixing screw 7, and the stage 11b, 11a issues a position adjustment instruction for the vertical, horizontal, and rotational displacements read when the substrate is opened. , 11d, and after adjusting the position in the vertical, horizontal, and rotational directions, the image sensor substrate fixing screw 7 is tightened. Then, the image sensor substrate fixing screw driver 8b retreats again, releases the grip of the image sensor substrate 2, repositions the mounting of the optical reading unit 5, and reads the vertical, horizontal, and rotational displacement of the image sensor.

<Step 4i> —Is the adjustment standard? If the vertical, horizontal, and rotational position deviations detected here fall within the specifications, the process proceeds to an adjustment procedure. If not, the image sensor substrate 2 is gripped again and the above adjustment is repeated. However, when the number of repetitions of the vertical, horizontal, and rotation direction fine adjustments is equal to or greater than the specified number, the adjustment is impossible and the process ends.

After the position adjustment in all the adjustment directions is completed, the position of each direction of the image sensor after the adjustment is displayed, the accuracy of the optical reading unit alone is guaranteed, and the clamp of the optical reading unit is released. Finish the adjustment normally.

[Second Embodiment] Instead of the triangular portions 902, 903, 905, and 906 of the pattern diagram a of the optical chart of the above embodiment, an oblique slit as shown in FIG. 7 may be used. In this case, the vertical displacement is determined by oblique slits 912 and 913 or oblique slit 91.
5 and 916 are detected as a set. Oblique slits 912, 9
13, the position of the center of gravity of the peak waveform of the image sensor signal 21 by the oblique slit 912 and the oblique slit 9
If the difference from the position of the center of gravity due to 13 is equal to or more than the reference value, the image sensor 1 is shifted upward. If the difference is less than the reference value, it is understood that the image sensor 1 is shifted downward. can get.

[Third Embodiment] An optical chart 9 in which a fixed optical chart 9 is formed three-dimensionally and a focus detection slit is provided at a focal position serving as a document position in the above-described embodiment and at defocus positions before and after the focal position. A chart may be used. FIG. 8 shows an example in which an optical chart is divided into a plurality of glass substrates, created, and then laminated to form one optical chart. The focus position includes a pattern 9 for detecting the vertical, horizontal, and rotational positions.
22, 923, 924, 925, 926 are provided. For focus detection, a slit pattern 921 is set at the focal position.
b, 927b, and slit patterns 921a, 921c, 927a,
927c is provided. And the slit portions 921a, 921
b, 921c, and 927a, 927b, and 927c, the focus position is obtained at three points in the focus direction and the focus position is calculated, so that the focus position can be detected while both the image sensor 1 and the optical chart 9 are fixed.

Further, the set position of the optical chart 9 in the above embodiment may be made variable by a position adjustment stage (not shown) to detect the focus position. In this case, instead of scanning the image sensor 1 in the defocus direction, the optical chart 9 is scanned in the defocus direction, and the focus position can be confirmed from the change in the degree of focus of the optical chart slits 901, 904, 907. By doing so, the focus position can be detected while the image sensor 1 is fixed.

By changing the position of the optical chart 9 with the position adjustment stage, the position of the optical chart can be easily adjusted to the reference original position of the optical reading unit. Become.
Further, it is possible to easily adjust the position of the optical chart on the adjuster side with reference to the standard optical reading unit.

[Fourth Embodiment] The surface of the substrate holding portion of the substrate holding pin of the above embodiment may be made of a material having a large friction such as rubber. Further, the substrate holding pin may also serve as the image sensor initial position setting pin. Further, the substrate gripping pins are only used to adjust the vertical, horizontal, and rotational directions of the image sensor 1, and when adjusting the position in the focus and tilt directions, a separately provided pin is inserted into a predetermined hole of the image sensor position setting bracket to adjust the position. Alternatively, the vertical, horizontal, and rotational directions, and the focus and tilt directions may be positioned by independent position drive pins.

According to the above embodiment, the position in each adjustment direction is not
Adjustment using only one optical chart with a detection pattern.
By changing the dedicated chart for each adjustment item,
And eliminate the error of replacing the chart every time.
You. In addition, the position shift detection pattern of the optical chart is
Enables transillumination by making it transmissive and uses transillumination
When the focal length of the optical reading unit is short due to
However, an optical system configuration that can easily obtain uniform illumination light can be obtained. Ma
The diffuser is located outside the depth of focus of the optical reading unit
By keeping the optical chart in close contact with the optical chart,
Optical unit is obtained, and the optical unit is
La is not affected. In addition, the image sensor
Providing means for detecting the amount of deviation from the optimal position;
Fixing and releasing the image sensor board for each fixed location
A mechanism can be provided to repeatedly fix and release the image sensor board
The position before fixing the image sensor board and fixing
Read the difference when fixing the image sensor board from the difference
The image sensor base
By correcting and adjusting the amount of displacement when fixing the plate, the position after fixing
Positioning accuracy can be guaranteed. Also, image sensor
Use three pins to grip the board and the gripper does not slip
With this structure, the image sensor board is
The position can be adjusted by holding
By setting the attitude when adjusting the board position to the attitude when opening the board,
It is possible to prevent a displacement before and after opening the substrate after the adjustment. Also,
Initial position regulation by abutting from the back of the image sensor board
Provision of a pin for adjusting the position of the board mechanically
The initial temporary fixing position of the image sensor board
Each time, the image sensor board can be held at almost the same position every time,
The position adjustment can be started from the same initial position every time . Also,
By making the image sensor fixing means variable in torque,
Weak when setting the reading means in the optical reading unit
Rotate with torque to increase the load torque when the set is completed.
Rotation stops, and confirms that the fixing means has been set.
You. Also, fix multiple fixing points on the image sensor board.
When fixing is completed, the part where fixing is completed first
The force transmitted to the place causes the board to be misaligned.
By fixing with high torque, the force is weak and small
Temporary fixing can be performed with the amount of board displacement suppressed, and then each
When fixing the fixing part, the board and board
Because of the contact friction between the mounting parts,
Compared to the case where the image sensor board is fixed,
The amount can be reduced. The present invention may be applied to a system including a plurality of devices or an apparatus including a single device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus.

[0064]

I to the present invention lever, of the image sensor quickly
In addition, it is possible to provide an automatic adjustment device for an optical reading unit that can perform accurate position adjustment.

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an automatic adjustment device for an optical reading unit according to the present embodiment.

FIG. 2 is a perspective view showing a structure of a mechanical part of the automatic adjustment device of the optical reading unit according to the embodiment.

FIG. 3 is a structural view of a driver tip portion.

FIG. 4 is a flowchart of an adjustment procedure.

5A and 5B are a conceptual diagram of an optical chart and a diagram showing an output signal waveform of an image sensor. FIG. 5A is a conceptual diagram of an optical chart, FIG. 5B is a waveform after adjustment, and FIG. The waveform when the camera is not in focus, (d) is in focus and in the tilt direction, but the image sensor 1 moves to the right, up,
The waveform when the image sensor 1 is displaced clockwise, (e) is the waveform when the image sensor 1 is displaced clockwise, and (f) is the waveform when the image sensor 1 is displaced downward and clockwise. It is a figure showing a waveform.

FIG. 6 is a diagram illustrating a degree of focus when scanning is performed in a focus direction.

FIG. 7 is a diagram showing an optical chart pattern according to a second embodiment.

FIG. 8 is a diagram showing an optical chart configuration according to a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image sensor, 2 ... Image sensor board, 3 ... Sef Foc lens array, 4 ... Image sensor position setting bracket, 5 ... Optical reading unit, 6 ... Image sensor position setting bracket fixing screw, 7 ... Image sensor substrate fixing screw, 8a: Image sensor position setting bracket fixing screw driver, 8b: Image sensor board fixing screw driver, 9 ...
Optical chart, 10a ... side board holding pin, 10b ... upper board holding pin, 11a ... left / right position adjustment stage, 11
b: Focus position adjustment stage, 11c: Rotation position adjustment stage, 11d: Vertical position adjustment stage, 11e: Tilt position adjustment stage, 12: Image sensor initial position setting pin, 13: Light source, 14: Diffusing plate, 15: Optical rail , 16 ... lower contact pin, 17 ... sliding piece, 20 ...
Small computer, 21 ... Image sensor signal, 22 ... Drive instruction signal, 23 ... Position adjustment stage, gripper and tightening driver, 801 ... Driver bit, 802 ... Flexible joint, 803 ... Angle restoring rubber, 804 ... Driver bit pressing spring, 805: Driver drive shaft, 90
1: optical chart slit section 1, 902: optical chart lower triangular section 2, 903: optical chart upper triangular section 3, 904
... Optical chart slit section 4, 905. Optical chart upper triangular section 5, 906. Optical chart lower triangular section 6, 907.
Optical chart slits 7 and 911: Optical chart slits 1 and 912 according to the second embodiment. Optical chart oblique slits 2 and 913 according to the second embodiment. Optical chart oblique slits 3 and 914 according to the second embodiment. Optical chart slits 4, 915: Optical chart oblique slits 5, 916 according to the second embodiment Optical chart oblique slits 6, 917: Optical chart slits 7, 921a according to the second embodiment According to the third embodiment Optical chart slits 1, 921b: Optical chart slits 1, 921c according to the third embodiment. Optical chart slits 1, 922 according to the third embodiment. Lower triangular portions 2, 923, optical chart according to the third embodiment. Optics according to the third embodiment. Upper triangular portion 3, 924 of the chart: optical chart slit portion 4 according to the third embodiment 925: Upper triangular portion 5, 926 of the optical chart according to the third embodiment, lower triangular portion 6, 927a of the optical chart according to the third embodiment, optical chart slit portion 7, 927b according to the third embodiment, optical chart slit portion 7, according to the third embodiment, 927c... Optical chart slit portion 7 according to the third embodiment

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-288484 (JP, A) JP-A-2-48868 (JP, A) JP-A-63-124021 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G05D 3/00-3/20 G02B 7/00 G02B 27/00-27/64

Claims (11)

(57) [Claims] 1. The image for an optical reading unit having a lens and an image sensor as basic components.
An automatic adjustment device for an optical reading unit for adjusting a position of a sensor, wherein the position of an optical chart serving as a reference for position adjustment is moved.
Moving means, and the optical chuck at a position moved by the moving means.
The image sensor is read by the image sensor.
The focal position of the lens is detected based on the output signal of the sensor.
A focus position detecting means for outputting the optical chart at a predetermined reference position.
To read the sensors, calculating means for sending a control signal to calculate a positional deviation amount of the image sensor from an output signal of the image sensor, the optical of the image sensor based on the control signal
Specifically a drive means for changing the position relative to the reading unit, the automatic adjustment device of the optical reading unit and having a, a fixing means for fixing the image sensor to the changed position by said driving means. 2. An illumination system for illuminating the optical chart.
2. The optical device according to claim 1, further comprising a light source.
Automatic adjustment device for the objective reading unit. 3. The automatic adjustment device for an optical reading unit according to claim 1, wherein the focus, tilt, left / right, up / down, and rotation positions can be adjusted. 4. The optical chart includes a focus, a tilt,
4. The automatic adjustment device for an optical reading unit according to claim 3 , further comprising a pattern for detecting a position shift in the left, right, up, and down directions, and wherein the pattern of each position shift detector is light transmissive. 5. The automatic adjustment device for an optical reading unit according to claim 2 , wherein said illumination means has a diffusion plate for obtaining uniform illumination light. 6. The illumination means transmits the optical chart.
The light according to claim 2, wherein the light is over-illuminated.
Automatic adjustment device of the biological reading unit. 7. The driving means is moved forward by the fixing means.
Serial so that optimum position after fixation in anticipation of displacement amount in fixing an image sensor, wherein said image sensor
The automatic adjustment device for an optical reading unit according to claim 1, wherein a position of the optical reading unit with respect to the optical reading unit is changed . 8. The optical reading device according to claim 1, wherein said driving means has three image sensor substrate holding pins and a pin for performing initial position adjustment by abutting from behind the image sensor substrate. Unit automatic adjustment device. 9. The gripping pin slides in a focus adjustment direction.
9. The surface structure according to claim 8, wherein the surface structure is difficult.
Automatic adjustment device for optical reading unit. 10. The automatic adjustment device of the optical reading unit according to claim 1, wherein the fixing means can repeat a fixing operation and a releasing operation independently for each fixing position. 11. The fixing means according to claim 1, wherein
11. The method according to claim 10, wherein the constant torque is variable.
Automatic adjustment device for optical reading unit