JP2003077141A - Optical head adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deal with two types of optical heads with an optical system of the same structure on the part of the adjusting device and to simply and easily realize the optical head adjustment with high accuracy. SOLUTION: The device is equipped with a collimator lens 3 in the optical head, a near infinity optical system composed of an image-forming lens 12 having a longer focal distance than the collimator lens 3, an image-pickup unit 13 for picking up the image formed by the image-forming lens 12, a lighting system including an illuminator 15 for projecting light to a light emitting element 2, an image processor 14, and a collimator lens driving means 16 to be controlled by the image processor 14. The image processor 14 uses difference-in- luminance information in a region near the emission point on the light emitting element image of the optical head which is irradiated with the lighting system; the image processor is thereby equipped with a calculating means for arithmetically processing the difference-in-luminance information, for the purpose of adjusting the position of the collimator lens 3 of the optical head by the collimator lens driving means 16.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to at least a light emitting element such as a laser diode that outputs laser light, a collimator lens that collects the laser light into parallel light, and an objective lens that collects the parallel light. The present invention relates to an optical head adjusting device for adjusting the position of a collimator lens in an optical head having a function of irradiating an information recording medium with laser light and converting the reflected light into an electric signal.

[0002]

2. Description of the Related Art A conventional example will be described below.

FIG. 16 is a block diagram of a conventional optical head adjusting device. Since a light emitting element such as a laser diode (hereinafter, also referred to as “LD”) used as a light source has a characteristic of astigmatic difference in which the light emitting point positions are different in the horizontal and vertical directions of the laser beam, the beam aspect ratio is different. (Aspect ratio of beam image) is significantly increased, resulting in an elliptical shape on the image.

Usually, the optical head corrects this,
It requires optical systems such as prisms and cylindrical lenses. However, the astigmatic difference may be slightly different depending on the light emitting element, or the characteristics of the optical element may vary.
"Astigmatism" occurs that the beam after passing through the objective lens has different focal lengths in the vertical and horizontal directions.

Therefore, if the beam condensed on the information recording medium (optical disk) in the optical disk device has astigmatism, it is affected by the information of the adjacent bits and tracks, and noise called crosstalk occurs. To do.
This astigmatism can be eliminated by finely adjusting the position of the collimator lens.

In the conventional adjustment of the optical head, the astigmatism is adjusted by observing the shape of the focused beam after passing through the objective lens and moving the position of the collimator lens. FIG. 16 shows an example of a conventional optical head adjusting device.

In the example shown in FIG. 16, the laser beam emitted from the light emitting element (for example, LD) 2 passes through the collimator lens 3 and advances in the optical head 1, and the laser beam changes its optical path by the mirror 4. Then, the beam spot focused by the objective lens 5 and reflected on the recording medium or the pseudo medium 11 simulating the recording medium is expanded,
The image formed by the imaging lens 12 is taken by the image pickup device 13. In addition, there is also one in which the laser beam after passing through the objective lens 5 is projected on a screen and the image is taken by the imaging device 13.

In this case, the image data picked up by the image pickup device 13 is taken into an image processing device such as a personal computer, and image processing is performed in the image processing device. Further, a collimator lens driving unit is provided which is capable of moving the collimator lens 3 in the optical axis direction. The collimator lens driving unit is controlled according to the image processing result of the image processing apparatus, and the collimator lens is driven by the driving unit. The astigmatism was adjusted while moving No. 3.

[0009]

SUMMARY OF THE INVENTION The above-mentioned conventional device has the following problems.

(1): 1 μm with astigmatism
Since it was very difficult to find the position of the focused beam spot below, there is a problem that the tact time (tact: man-hour, tact time: time required for working process) increases. Further, it is difficult to quantify the observed beam shape, and there is a problem that the adjustment result varies.

Further, in order to observe the shape of the beam spot condensed by the objective lens, an optical system for enlarging is indispensable, so the optical system becomes complicated and the optical system for observation and the optical axis of the optical head. Will be difficult to match. In order to solve these problems, it becomes a problem to take an image with a wide field of view and a simple optical system and quantify the adjustment state of the collimator lens from the taken image of the light emitting element.

(2): On the other hand, in an optical head using a light emitting element having a sufficiently small astigmatic difference, an optical system for aspect ratio correction is not necessary and it is not necessary to adjust astigmatism. It is not necessary to see the beam shape after passing through the lens.

Therefore, it is not desirable to separately develop optimum adjusting devices for optical heads having different optical systems depending on the astigmatic difference characteristics of the light emitting element, because the development cost and period increase. Therefore, on the adjustment device side, both types of the same optical system, that is, a type that does not require an optical system for aspect ratio correction and a type that requires an optical system for aspect ratio correction, The challenge is to be compatible with optical heads.

The present invention solves such a conventional problem and makes it possible for both the type 1 and type 2 optical heads to use an optical system of the same configuration on the adjusting device side. It is an object of the present invention to enable head adjustment with high accuracy, easily and easily.

[0015]

In order to achieve the above object, the present invention has the following constitution.

(1): In the optical head adjusting device, an infinity optical system (actually, the infinite optical system is composed of a collimating lens in the optical head and an imaging lens having a focal length longer than that of the collimating lens). Even if you make it, an error will occur, so in the following explanation it will be referred to as "substantially infinity optical system"),
An imaging device that captures an image formed by the imaging lens, an illumination system that includes an illumination device that illuminates a light emitting element in the optical head with illumination light for imaging, and an image is captured from the imaging device. With an image processing device that performs image processing in, and a collimating lens driving device that drives the collimating lens position based on image information processed by the image processing device, the image processing device, the illumination light by the illumination system. From the light emitting element image of the optical head imaged in the illuminated state, the luminance difference in the light emitting point vicinity region, which is the minimum range necessary for image processing, for adjusting the collimating lens position of the optical head by the collimating lens driving device. It is characterized in that it comprises a calculation means for calculating information.

(2): In the optical head adjusting device of (1), the image processing device is necessary for image processing on the light emitting element image with respect to the optical head having an optical element for aspect ratio correction. The astigmatism is controlled by driving the collimator lens by the collimator lens driving device by adjusting the ratio of the orthogonal component of the luminance difference information in the light emitting point vicinity region, which is the minimum range, to a predetermined value. It is characterized in that it is provided with a computing means for computing information for doing so.

(3): In the optical head adjusting device according to (1) or (2) above, the image processing device emphasizes the light emitting point, and therefore, the minimum necessary for image processing on the excited light emitting element image. Using the brightness difference information obtained from the area near the light emitting point, which is the range of 1), the collimator lens driving device is provided with arithmetic means for calculating information for adjusting the collimator lens position of the optical head. .

(4): In the optical head adjusting device of (3), the image processing device energizes the light emitting element in order to emphasize the light emitting point, and on the light emitting element image in an excited state,
Using the brightness difference information obtained from the vicinity of the light emitting point, which is the minimum range necessary for image processing, a calculating means for calculating information for adjusting the collimating lens position of the optical head by the collimating lens driving device is provided. It is characterized by being

(5): In the optical head adjusting device according to (3), the image processing device emphasizes the light emitting point without energizing the light emitting element, so that the light emission is in a state excited by the irradiation light from the lighting device. Information for adjusting the collimating lens position of the optical head by the collimating lens driving device is calculated by using the brightness difference information obtained from the light emitting point vicinity region which is the minimum necessary range for image processing on the element image. It is characterized in that it is provided with a computing means.

(Operation) (a): In the above (1), since the laser beam after passing through the collimator lens is observed, the position of the collimator lens can be adjusted before attaching the objective lens. Further, in the conventional example, in order to image the laser beam after passing through the objective lens, it is necessary to search for a beam spot of 1 μm or less, which increases the takt time. However, in the present invention, before focusing by the objective lens. Since the laser beam is imaged, the tact time can be shortened.

(B): In the above (2), the ratio of the orthogonal component (horizontal component and vertical component) of the brightness difference information in the vicinity of the light emitting point on the light emitting element image with respect to the optical head having the aspect ratio correction optical system. It becomes possible to control astigmatism by adjusting to a predetermined value.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the brightness difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

(C): In (3), since the light emitting point in the LED light emitting state or the photoluminescence light emitting state is observed,
Even if the grayscale difference in the vicinity of the light emitting point is not sufficient, it becomes possible to accurately search for the light emitting point by applying a pattern search method such as template matching or maximum brightness search. It can be calculated with high accuracy.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the luminance difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

(D): In the above (4), since the light emitting point in the LED light emitting state or the photoluminescence light emitting state is observed,
Even if the grayscale difference in the vicinity of the light emitting point is not sufficient, it becomes possible to accurately search for the light emitting point by applying a pattern search method such as template matching or maximum brightness search. It can be calculated with high accuracy.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the luminance difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

(E): In the above (5), since the light emitting point in the LED light emitting state or the photoluminescence light emitting state is observed,
Even if the grayscale difference in the vicinity of the light emitting point is not sufficient, it becomes possible to accurately search for the light emitting point by applying a pattern search method such as template matching or maximum brightness search. It can be calculated with high accuracy.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the brightness difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

§1: Outline of Optical Head Adjusting Device An outline of the optical head adjusting device will be described below with reference to FIGS.

(1): In the apparatus shown in FIG. 1A, the light emitting element 2 and the collimating lens 3 are provided on the adjusted device side (optical head side), but the aspect ratio correction optical system is provided. Absent. A type in which the device to be adjusted (optical head side) does not have an aspect ratio correction optical system is hereinafter referred to as “type 1”.

In the apparatus shown in FIG. 1B, the aspect ratio correction optical system 19 is provided on the adjusted device side (optical head side) in addition to the light emitting element 2 and the collimating lens 3. The type in which the aspect ratio correction optical system 19 is provided on the device to be adjusted side (optical head side) in this way is hereinafter referred to as “type 2”.

The type 1 and type 2 adjusting devices are provided with a light source such as a halogen lamp, and an illumination system including an illuminating device 15 for illuminating the light emitting element 2, an imaging lens 12, An image pickup device 13, an image processing device (for example, a personal computer) 14, a collimator lens driving device 16, and a light emitting element driving device 17 are provided.

In the types 1 and 2, the collimating lens 3 in the optical head and the imaging lens (imaging lens group) 12 having a focal length longer than that of the collimating lens 3 constitute a substantially infinite optical system. An image pickup device 13 for picking up an image formed by the image lens 12 and a lighting device 15 for outputting an illumination light for picking up an image pick up a light emitting element image of an optical head, and the image processing device 14 uses the lighting system. The brightness difference information for adjusting the position of the collimator lens 3 of the optical head by the collimator lens driving device 16 is used by using the brightness difference information of the area near the light emitting point on the light emitting element image of the optical head captured in the state of being illuminated by Compute information.

Then, the collimator lens driving device 16 moves the position of the collimator lens 3 based on the information (luminance difference information) output from the image processing device 14.

(2): Also, type 2 shown in FIG. 1B.
As described above, when the optical head has the aspect ratio correction optical system 19, the ratio of the orthogonal component (horizontal component and vertical component) of the brightness difference information is adjusted to be a predetermined value. . Here, the “horizontal direction” refers to the correction direction by the aspect ratio correction optical system 19, and the vertical direction refers to the direction orthogonal to the horizontal direction. It should be noted that the configuration of the adjusting device side does not change even for the optical head including the aspect ratio correction optical system 19 like the type 2.

Here, as for the brightness difference information, if there is a pattern peculiar to the periphery of the light emitting point on the light emitting element image, the brightness difference information obtained directly from this pattern may be used.
Alternatively, an extremely weak current is applied to the light emitting element 2 to illuminate the brightness difference information of the light emitting pattern of the light emitting element 2 in the LED light emitting state, the illumination light from the lighting device 15, and the like to emit light in the photoluminescence light emitting state. It is also possible to use the brightness difference information of the light emission pattern of the element 2.

(3): FIG. 2 is an explanatory diagram of the image processing apparatus, FIG. A is a block diagram of the image processing apparatus, and FIG. The image processing device 14 inputs the output image of the imaging device 13 shown in FIG. 1 and performs image processing. In this case, the image processing device 14 is composed of, for example, a personal computer (PC), and internally has a CPU 21,
Program storage means (hard disk device, ROM, etc.)
22, an image memory 23 for storing an input image,
A work memory 24 and the like used by the CPU 21 for work are provided.

Then, the CPU 21 reads out the program from the program storage means 22 and executes it to perform image processing and the like (including control of the collimator lens driving device 16 and the light emitting element driving device 17) described below. The process shown in FIG. 2B shows the flow of the process for obtaining the brightness difference information, and S100 to S102 show each process step.

First, in the image processing device 14, the image pickup device 1
Input the image captured by 3 and use this image in the CPU
It is temporarily stored in the image memory 23 under the control of 21. After that, the CPU 21 acquires the end face image of the light emitting element 2 from the images stored in the image memory 23, and acquires the work memory 24.
(S100).

Next, the CPU 21 extracts an image near the light emitting point from the image in the work memory 24 (S101). Then, the brightness difference information is calculated from the extracted image. In this case, the CPU 21 searches for the light emitting point from the light emitting element image to obtain the brightness difference information only for the light emitting point, and calculates the brightness difference information from the region near the light emitting point (S102).

As described above, by forming the substantially infinite optical system including the collimating lens 3 in the optical head and the image forming lens 12 having a focal length longer than that of the collimating lens 3, the light emitting element 1 is laterally moved. Since it is possible to magnify and observe the magnification and the vertical magnification, the resolution of the brightness difference information of the image in which the position of the collimator lens 3 is observed is high, and the adjustment can be performed accurately.

Since the beam after passing through the objective lens 5 is not observed, the field of view can be set wide. A complicated optical system for expanding the beam spot after passing through the objective lens 5 is not required, and the optical axes of the optical head and the imaging system can be easily aligned.

By adjusting the ratio of the orthogonal component (horizontal component and vertical component) of the brightness difference information to a predetermined value, astigmatism can be achieved with respect to the optical head including the aspect ratio correction optical system 19. Aberration can be adjusted. In this case, since the LED light emission pattern or the photoluminescence light emission pattern can be used, the light emission point position can be detected and the brightness difference information can be acquired without a specific pattern near the light emission point of the light emitting element.

§2: Detailed description of specific example Hereinafter, specific examples will be described in detail.

(1): Specific Example of Optical Head Adjusting Device FIG. 3 is an explanatory view of the device, showing a specific example of the optical head adjusting device. As shown in FIG. 3, the optical head includes a fixed optical system 26 including a light emitting element 2, a light receiving element, a collimating lens 3 and the like, an objective lens 5 and the like, and a movable optical system that is movable in the radial direction of the recording medium. It is composed of 27.

The optical head adjustment device includes an illumination system 29 including the half mirror 32 and the illumination device 15, an imaging system 28 including the imaging lens 12, the image pickup device 13 and the image processing device 14, and a collimator lens drive device 16. And a light emitting element driving device 17, a mirror 4 and the like.

In the above construction, in order to avoid interference with the movable optical system 27, the optical axis is deflected by the mirror 4. In the configuration of FIG. 3, the mirror 4 is arranged at two places. The mirror 4 is not essential because it only considers the ease of disposing the imaging device 13 and the illumination device 15. Further, for the same reason, the arrangement order of the illumination system 29 including the mirror 4 and the illumination device 15 may be reversed.

The collimator lens driving device 16 is composed of an actuator for driving the collimator lens 3, a servomotor for driving the actuator, a control circuit for controlling the driving of these, and the like.
The collimator lens 3 is configured to be movable in the optical axis direction (arrow direction in the drawing) based on the output signal from the image processing device 14.

The light emitting element driving device 17 is composed of an actuator for driving the light emitting element 2, a servomotor for driving the actuator, a control circuit for controlling the driving of the actuator, and the like. Processor 1
The light emitting element 2 can be moved in the direction orthogonal to the optical axis (the direction of the arrow in the figure) based on the output signal from the optical disc 4.

The collimator lens driving device 16
Is a known device as described in, for example, Japanese Patent Laid-Open No. 7-249235, and the light emitting element driving device 17
Also, since it has the same structure as the collimator lens driving device 16 and is a known device, detailed description thereof will be omitted.

(2): FIG. 4 is an explanatory view of an arrangement example, and FIG.
FIG. 3D is a diagram three-dimensionally showing the arrangement of each part shown in the configuration of the specific example of FIG. As shown in FIG. 4, the optical axes of the collimator lens 3 and the imaging lens 12 are preliminarily positioned so as to coincide with each other, and on the adjusted device side, the collimator lens 3 should be moved in the optical axis direction. It has a structure that allows The camera 31 (a specific example of the imaging device 13) and the imaging lens 12 are positioned so that the optical axis thereof coincides with the center of the imaged image. A monitor 33 is connected to the image processing apparatus 14, and an image to be image-processed or the like can be displayed on the screen of the monitor 33.

(3): In the image processing by the image processing device 14, when the light emitting point is on the optical axis, A in FIG.
As shown, the light emission point 34 is located at the center of the image. The light emitting point vicinity region 35 is shown by a portion surrounded by a thick frame in the figure. Further, the image pickup element surface (in this example, the CCD element surface) of the image pickup device 13 is made to coincide with the focal length of the imaging lens 12. By arranging in this way, a substantially infinity optical system is constructed, and therefore the observation target is the collimator lens 3
The sharpest image is obtained at the focal length of.

However, when the work of moving the position of the collimator lens 3 is being performed, it is possible that the object to be imaged moves on the screen as shown in FIG. 5B. As a factor thereof, when the collimator lens driving device 16 comes into contact with the collimator lens 3 or the lens barrel of the collimator lens 3,
Since a certain amount of force is applied to the optical head,
It is conceivable that the optical axis of the optical head may be slightly displaced from the optical head adjusting device.

For example, although not shown, if there is a cushioning mechanism between the optical head and the table that supports the optical head, or if there is a gap between the collimator lens 3 and the base of the optical head, the optical The case where distortion occurs in the head or the lens barrel of the collimator lens 3 may be mentioned. In such a case, the light emitting point position (the position of the light emitting point 34) on the screen is tracked as the light emitting point search processing (processing by executing the program) in the processing flow shown in FIG. 2B. To do.

In order to perform the tracking process, the image of the light emitting point vicinity area 35 prepared in advance or the image of the light emitting point vicinity area 35 at the initial position is used as a template, and the image is compared with the template by a matching method such as a cross correlation method. A place with a high degree of coincidence is detected as a light emitting point position.

For image processing such as search processing and luminance difference information calculation processing, a pattern peculiar to the light emitting point around the light emitting element 2,
Either the light emitting pattern of the light emitting element in the LED light emitting state or the light emitting pattern of the light emitting element in the photoluminescence light emitting state is used. When the brightness of the light emitting point is higher than the surrounding brightness, the maximum brightness value may be regarded as the light emitting point and the search process may be performed.

When the light emitting point is at the focal position of the collimator lens 3, the light from the light source on the light emitting point 34 becomes parallel light after passing through the collimator lens 3, and the image picked up becomes the clearest (FIG. 6). (See Figure A). On the contrary, when the light emitting point is not located at the focal position of the collimator lens, the captured image is blurred (see FIG. 6B). Temporarily, an image of a stepwise pattern of brightness is picked up and the boundary is focused.

At this time, as shown in FIG. 7, the brightness difference between adjacent pixels across the boundary becomes smaller as the image blurs, and becomes maximum when the image looks clearest. As shown in FIG. 7C, the change in the brightness difference information depending on the position of the collimator lens 3 is maximum when the collimator lens 3 is at the in-focus position, and the brightness difference information increases as the distance from the in-focus position increases. Becomes smaller.

As shown in FIG. 8, since the brightness difference information is distributed in the range along the boundary, it is necessary to calculate the representative value. In an ideal situation, the brightness difference is as shown in FIG.
Since the distribution is as shown in FIG. B, the maximum value may be used as the representative value. However, since the maximum value of the acquired image varies due to quantization error, thermal noise, etc., the accuracy may deteriorate.

Therefore, the variation may be reduced by using the average value of the values in the vicinity of the maximum value. In order to obtain a value near the maximum value, it is necessary to search for a pixel having the maximum value of the brightness difference. This process takes time and only local information can be obtained.
It is also possible to create a histogram for the luminance difference and to obtain the average luminance difference value for a predetermined number of pixels from the larger value.

By doing so, it is possible to more reflect the brightness difference on the ridge. Further, if there is an influence of vibration of the floor or the air, or an influence of illumination fluctuation, a moving average of the brightness difference information for several frames may be used. Although the above description is an example of type 1, type 2 is as follows.

That is, in the case of type 2, the collimating lens 3 of the optical head including the aspect ratio correction optical system 19
When the position of is adjusted, the magnification differs in the orthogonal direction (horizontal direction and vertical direction), and the light emitting element 2 has astigmatism.
As shown in the schematic diagram of FIG. 9, for example, even if the vertical (vertical) edge is sharpest, the horizontal (horizontal) edge may be blurred.

In this example, in the luminance difference information, the horizontal component (horizontal component) corresponding to the edge in the vertical direction (vertical direction) becomes strong as shown in the schematic diagram of FIG. The (vertical component) becomes weaker as shown in the schematic diagram of FIG. Therefore, it is necessary to observe the luminance difference information separately for the orthogonal component (vertical component and horizontal component).

Here, the position of the objective lens 5 which is the focal point with respect to the collimator lens position draws different loci as shown in FIG. 10A, and the objective lens 5 becomes the same position at a certain specific position. . That is, it is possible to make an adjustment to cancel astigmatism. When the difference between the in-focus position of the vertical component (vertical component) and the in-focus position of the horizontal component (horizontal component) is called astigmatism, the position of the collimator lens 3 is e, and the focal length of the collimator lens 3 is Fc, the focal length of the objective lens 5 is fo, and the aspect ratio correction optical system 1
Assuming that the lateral magnification (horizontal direction) of 9 is γ (> 0) and the astigmatic difference of the light emitting element is δ, the astigmatism value D is approximately:

[0067]

[Equation 1]

Thus, as shown in FIG. 10B, the position of the collimator lens 3 is uniquely determined. Further, assuming that the focal length of the imaging lens 12 is f, the same relationship can be derived because it is simply replaced with f _{0 in} the above equation. Therefore, if the relationship between the orthogonal components (vertical component and horizontal component) of the brightness difference information at the position of the collimator lens 3 where the astigmatism is 0 can be obtained in advance, the adjustment can be performed without the objective lens. .

However, the value of the brightness difference information itself changes if the amount of illumination light from the illuminating device 15 or the light and shade of the light emitting point pattern is different. For example, when an LED light emission pattern is used, the light emission intensity may be different depending on the characteristics of individual light emitting elements even when the same current is applied. In order to cancel the change in the intensity of the illumination light and the change in the density of the light emission pattern, the ratio of the orthogonal component (vertical component and horizontal component) of the luminance difference information is used. Hereinafter, the ratio will be referred to as a “luminance difference information ratio”.

As shown in FIG. 11, since there is a difference in the astigmatic difference of the light emitting element 2 and the magnification by the aspect ratio correction optical system 19, the luminance difference information has orthogonal components (vertical component and horizontal component).
With different characteristics. Therefore, the luminance difference information ratio has sensitivity depending on the position of the collimator lens 3.

However, since the brightness difference information ratio forms a curve, when the movable range of the position of the collimator lens 3 is wide, the same value may be obtained at the positions of the collimator lens 3 having different brightness difference information ratios. As shown in FIG. 11, the brightness difference information has a vertical direction component (vertical direction component) or a horizontal direction component (horizontal direction component) even if the brightness difference information ratio has the same value.
Since the values of are different, it is possible to determine the position where the astigmatism is zero.

In FIG. 11, the dotted curve shown on the upper side of the figure is the horizontal component of the luminance difference information, and the solid line is the vertical component of the luminance difference information. Further, the curve shown on the lower side of FIG. 11 is a curve showing the ratio of the vertical component and the horizontal component.

FIG. 12 shows the relationship between the astigmatism and the luminance difference information, and the point where the curve representing the ratio of the vertical component to the horizontal component intersects the line of astigmatism value 0 is the objective lens. It is illustrated that the beam after transmission has luminance difference information with zero astigmatism.

§3: Detailed description of processing of image processing apparatus In the processing shown in FIGS. 13 to 15 described below, the CPU 21 of the image processing apparatus 14 (for example, a personal computer) shown in FIG. 2 executes a program. This is a process performed by reading a program from the storage unit 22 (for example, a hard disk device).

The position of the collimator lens is moved by driving the collimator lens driving device 16 based on the information (control information of the image processing result) output from the image processing device 14 (for example, driving of a servo motor). By driving the actuator). Further, the position of the light emitting element is moved by driving the light emitting element driving device 17 based on the information (control information of the image processing result) output from the image processing device 14 (for example,
This is performed by driving the actuator by driving the servo motor).

(1): Description of Process 1 FIG. 13 is a process flowchart for coarse adjustment of the collimator lens and adjustment of the light emitting elements in the optical heads of types 1 and 2. Hereinafter, the process of coarse adjustment of the collimator lens and adjustment of the light emitting element in the optical heads of types 1 and 2 will be described with reference to FIG. Note that S1 to S11 indicate processing steps.

Optical head (type 1) without aspect ratio correction optical system 19 and aspect ratio correction optical system 1
In both of the 9 optical heads (Type 2), it is necessary to position the light emitting element 2 so that the light emitting points coincide with each other. This is because the further the distance from the optical axis, the greater the influence of aberration, so that the image is not focused on the entire image.

Therefore, the light emitting element 2 is positioned and adjusted before the position of the collimator lens 3 is adjusted. Then, the position of the collimator lens 3 is adjusted (this is referred to as "coarse adjustment") so that the light emitting element image is focused to some extent.

Here, it is necessary to perform a process suitable for the process (S4) of detecting the light emitting position depending on the image pickup conditions. In the process of FIG. 13, the process is performed in a state in which an operating current is passed through the light emitting element 2 to cause laser emission, or in a state in which a weak current equal to or less than a threshold current is passed through the light emitting element 2 to cause LED emission.

When the optical axis direction is the Z direction, the collimator lens 3 is movable only in the Z direction, and the light emitting element 2 is movable in the XY plane orthogonal to the Z direction. The image pickup surface is a surface parallel to the XY plane and is calibrated so that the optical axis coincides with the center of the image.

First, in S1, parameters such as deviation are initialized, and in S2, each element is moved to the initial position. In S3, the image of the end surface of the light emitting element 2 is acquired from the image pickup device 13 and stored in the image memory 23. S4
The coarse adjustment of the collimator lens 3 is performed in S8 to S7, and S8 to S
At 11, the position of the light emitting element 2 is adjusted. In this processing, the position of the light emitting element is adjusted while confirming the position of the collimator lens 3 in S5 and S6, but immediately after initialization, it is determined in S6 that it is not in focus, and S5 is processed between S6 and S7. Thus, the procedure may be such that the position of the collimator lens 3 is not confirmed after the coarse adjustment of the position of the collimator lens 3.

Since the luminance distribution at the light emitting point shows a Gaussian distribution in which the value decreases from the center to the outside, the pixel having the maximum luminance value on the image is regarded as the light emitting point for detecting the light emitting point position in S4. Realized by In the case of detecting the position with higher accuracy than the pixel unit arranged in a grid, the brightness center in the vicinity of the pixel having the maximum brightness value on the image may be set as the light emitting point position.

Here, the "neighborhood" refers to an area which is connected to a pixel having a maximum brightness value and includes a pixel having a brightness of 1/2 or 1 / e ² of the maximum brightness value. The e is the base of the natural logarithm and has a value of e = 2.7182818.

The focus state calculated in S5 is represented by the maximum brightness value or the area of the area near the pixel having the maximum brightness value. That is, the maximum luminance value decreases and the area increases as the position of the collimator lens 3 moves out of focus.

At S6, it is determined whether the position of the collimator lens 3 is at the in-focus position based on the in-focus information calculated at S5. In the case where the maximum brightness value is used for determination, the position of the collimator lens 3 having the largest value among the maximum brightness values measured for each position of the collimator lens 3 is determined to be the in-focus point.

In the case of using the area of the above-mentioned neighboring region, conversely, the position of the collimator lens 3 having the smallest value is determined to be the in-focus point. However, when the light emission intensity of the light emitting element 2 is high and the image pickup device 13 is saturated, the determination cannot be made only by the maximum luminance value, and therefore the determination is made using the ratio of the two. For example, if the maximum brightness / near area area is used as the focus information, the collimating lens 3 having the largest value is obtained.
The position of is determined to be the in-focus point.

The position movement interval of the collimator lens 3 in S7 must be smaller than the depth of focus at the position of the collimator lens 3. In S8, the deviation of the light emitting point position on the image is calculated with reference to the optical axis position. That is, the numbers of pixels in the horizontal and vertical directions from the center of the image are calculated.

In S9, the deviation e obtained in S8, the optical magnification β obtained from the collimating lens focal length f1 and the imaging lens focal length f2, and the interval p between the light receiving cells arranged in a lattice on the image sensor are determined. The distance D for moving the light emitting element is calculated from the following equation. Here, e and D are norms.

D = e · p / β Equation (1) (where β
= F2 / f1) When the tilt angle of the laser beam with respect to the ideal optical axis is defined, this angle δ is calculated from the distance D by the following equation.

Δ = tan ⁻¹ (f2 / D) (Equation (2)) In S10, if δ is greater than or equal to the specified value, the light emitting element is moved in S11, and if less than the specified value, adjustment is completed. .

The above processing is summarized as follows. First, after the process is started, an initialization process is performed (S1), and the positions of the light emitting element and the collimator lens are moved to the initial position (S).
2).

In this case, the collimating lens driving device 16 and the light emitting element driving device 17 are driven by the control information from the image processing device 14, and the light emitting element 2 and the collimating lens 3 are driven.
To start scanning.

Next, an image of the end face of the light emitting element is acquired from the image pickup device and stored in the memory (work memory 24) (S3),
The light emitting point position is detected (S4). Next, the focus position is calculated (S5), and it is determined whether the collimator lens position is located at the focus position (S6). As a result, when the collimator lens position is not located at the in-focus position, the position of the collimator lens is moved (S7), and the process proceeds to S3.

In the process of S6, when the collimator lens position is located at the in-focus position, the deviation of the light emitting point position on the image with respect to the optical axis position is calculated (S8), and the deviation is calculated. The deviation based on the optical axis is calculated from the parameters of the optical system (S9). Next, it is judged whether or not the tilt of the optical axis exceeds the threshold value (S10), and if it exceeds the threshold value, this processing is terminated. If not, the light emitting element is moved so that the positional deviation becomes zero. Then (S11), the process proceeds to S3.

(2): Description of Process 2 FIG. 14 is a process flowchart for fine adjustment of the collimator lens in the type 1 optical head. Below, FIG.
Based on the above, the processing for fine adjustment of the collimator lens in the type 1 optical head will be described. Note that S21 to S31
Indicates each processing step. Note that this process is a process performed after the process of FIG. 13 is completed.

First, an example of an optical head (type 1 optical head) without an aspect ratio correction optical system will be described. As shown in FIG. 10, the brightness difference information has a characteristic that it takes a maximum value at the in-focus position of the light emitting element image with respect to the position of the collimator lens 3. Therefore, adjustment is performed by moving the collimator lens 3 to a position where the brightness difference information has the maximum value.

The movement interval of the collimator lens 3 is as shown in FIG.
Based on the above, the interval (fine adjustment interval) is made smaller than the value used for the rough adjustment described above. Collimating lens 3
It suffices that the moving range of is about several times the depth of focus of the collimator lens 3 with respect to the position of the collimator lens 3 positioned by rough adjustment.

Here, as the image pickup condition, in order to increase the brightness difference and increase the resolution, the light emitting element 2 is set to the excited light emission state by the illumination light from the illumination device 15 or the excited light emission state by the weak current. Since the light emitting point is emphasized, it is necessary to use the former illumination light having a wavelength shorter than the light emission wavelength of the light emitting element 2 by several nm to several tens nm.

For example, when the light emitting element 2 is a laser diode which emits visible laser light, and the emission wavelength is in the band of 650 to 700 nm which is widely used in optical disk devices, a white light source such as a halogen lamp is used. On the other hand, the light emitting element 2 is excited by using the illumination light having a wavelength longer than 600 nm by the low-pass filter having a cutoff of 600 nm. This is called the photoluminescence phenomenon.

On the other hand, when a weak current that does not exceed the threshold current is passed, laser emission does not occur, but an electroluminescence phenomenon occurs in which the laser is excited as in the LED. Any excitation light is observed over the entire active layer formed on the light emitting element 2, but since the brightness at the light emitting point is higher than that of the surroundings, the light emitting point is emphasized on the image.

Since the collimator lens 3 is usually a single lens and has a chromatic aberration in which the focal length differs depending on the transmission wavelength, when it is desired to focus only on the light emitting point, it is necessary to simply image the light emitting point with illumination light. The position adjustment accuracy of the collimator lens 3 deteriorates.

For example, when white light is emitted through the collimating lens 3 having a chromatic aberration characteristic of 10 μm / nm, the sensitivity range of the image pickup device (eg CCD) is 4
Considering that an image obtained by using the imaging device 13 having a wavelength of 00 nm to 700 nm has a width of a focal length of 3 mm, compared with the fact that the depth of focus of the collimator lens 3 is several μm, the adjustment accuracy Degradation is obvious.

Here, the reason why the laser is not emitted is that when the light emitting point in the state where the laser is emitted is imaged, the light intensity becomes stronger as the position of the collimator lens 3 gets closer to the in-focus position. Since the saturation is exceeded, the in-focus state cannot be accurately determined, and if an attenuation filter is inserted so that the brightness of the light emission point on the image in the in-focus state falls within the dynamic range of the image sensor, it will be slightly out of focus. There is a problem in image processing such that the laser light cannot be detected by the image pickup device only when it is out of the range. On the other hand, it is easy to adjust the illumination light amount and the weak current so that the light emitting element in the weak excited light emitting state falls within the dynamic range of the image pickup element.

Step S21 is an initialization process, which performs processes such as parameter and initial position movement of the collimator lens driving device 16 for the subsequent process. For the processing of S24, which will be described later, an image of a region including a characteristic brightness undulation near the light emitting point is stored in the work memory 24 as a template. However, it is premised that the position of the collimator lens 3 is roughly adjusted by the above-described procedure (processing of FIG. 13).

S22 and S31 are commands (scan start command / scan stop command) to the collimator lens driving device 16, S23 to S25 are image processing for calculating the brightness difference information from the image, and S26 to S30 are brightness. This is data processing for determining the adjustment state of the collimator lens 3 using the difference information.

At S22, a driving system for scanning the position of the collimator lens 3 (collimator lens driving device 1
Send a scan start command to 6). However, collimating lens 3
When the image is picked up while moving the, the image picked up is disturbed due to vibration or the like. Synchronize, such as pause. This turbulence means the imaging device 13
This occurs because the image pickup timing is slightly different between the even field and the odd field when the image is picked up.
For example, the "RS17" format differs by about 16.7 msec.

In step S24, the light emitting point position is detected by performing template matching using the template produced in the initialization of step S21, and the light emitting point vicinity region is detected. Here, the “region near the light emitting point” is a region including a range in which the boundary line around the light emitting point is blurred and widened when the position of the collimator lens 3 deviates from the in-focus position. At least, it is a range expanded from the periphery of the light emitting point by several pixels.

In S25, the brightness difference information is calculated for the light emitting point vicinity region extracted in S24. Here, the “brightness difference information” is an integration of values having sufficiently large values among the brightnesses of adjacent pixels. As shown in FIG. 6, when the image blurs, the inclination of the boundary line gradually decreases. However, the boundary line becomes an inflection point of the brightness change. As shown in FIG. 7B, the value on the boundary line is the largest on the line orthogonal to the boundary line, and the sensitivity to the displacement of the position of the collimator lens 3 is the highest. That is, there is a very high possibility that a pixel having a sufficiently large difference in brightness will coincide with the boundary line.

Therefore, in order to enhance the sensitivity with respect to the position of the collimator lens 3, the number of pixels to be integrated is made equal to the number of pixels on the boundary line surrounding the light emitting point. The image sensor is
Due to thermal noise and differences in characteristics between the even line field and the odd line field, the brightness difference for each pixel includes variations. The integration of the brightness difference has the effect of reducing such variations. As a method of calculating the brightness difference, a Sobel operator or the like can be used.

In the processing of S25, in order to further reduce the variation and improve the resolution, the calculated luminance difference information is stored in the work memory 24, and the time average of a plurality of values processed at the same position of the collimating lens 3 is obtained. May be calculated.

In step S26, the position of the collimator lens 3 having the highest luminance difference information is detected, so a comparison process is performed to hold a value larger than the luminance difference information calculated in the immediately preceding loop, and the result of the comparison. If the value is large, the value held in S27 is updated. The above processing is performed until the set moving range of the collimator lens 3 has completed one cycle.

In S28, it is determined whether or not there is one round, and if it has, the threshold value is calculated in the next S29. After the threshold value is calculated, while further scanning the collimator lens 3, the brightness difference information calculation process, the maximum update process, and the threshold value update process from S23 to S29 are performed, and when it is determined in S30 that the brightness difference information exceeds the threshold value. Adjustment is complete.

The above processing is summarized as follows. First, after the start of processing, initialization processing is performed (S21), and scanning of the light emitting element and collimating lens positions is started (S2).
2).

In this case, the collimating lens driving device 16 and the light emitting element driving device 17 are driven by the control information from the image processing device 14, and the light emitting element 2 and the collimating lens 3 are driven.
To start scanning.

Next, the CPU 21 acquires an image of the end face of the light emitting element from the image pickup device and stores it in the memory (image memory 23 and work memory 24) (S23). Next, a region near the light emitting point is extracted by template matching (S2
4) The brightness difference information is calculated (S25).

Then, it is judged whether or not the brightness difference information exceeds the maximum value of the brightness difference information (S26). If it does not exceed, the process proceeds to S23, and if it exceeds, the process proceeds to S27. In the process of S27, the maximum value of the brightness difference information is updated (S27), and it is determined whether the collimator lens position has been scanned (S28).

As a result, if the collimator lens position has not been scanned, the process proceeds to S23. If the collimator lens position has been scanned, a threshold value is calculated from the maximum value of the brightness difference information (S29), and the brightness difference information is calculated. Is determined to exceed the threshold value (S30). As a result, if the brightness difference information does not exceed the threshold value, the process proceeds to S23, and if the brightness difference information exceeds the threshold value, the collimator lens position scanning is stopped. Then, this process ends.

(3): Description of Process 3 FIG. 15 is a process flowchart for fine adjustment of the collimator lens in the type 2 optical head. Below, FIG.
Based on the above, processing at the time of fine adjustment of the collimator lens in the type 2 optical head will be described. Note that S41 to S47
Indicates each processing step.

This process is a process performed after the process of FIG. 13 is completed. In this example, the adjustment is completed by matching the ratio of the luminance difference information of the orthogonal components with a predetermined value. This "predetermined value" is ideally the ratio of the brightness difference information measured at the position of the collimator lens 3 when the astigmatism becomes 0 in the laser light after passing through the objective lens. Alternatively,
It may be the ratio of the brightness difference information measured with respect to the optical head of the device having the lowest error rate.

In this procedure, a case will be described in which a weak current is applied to the light emitting element 2 as an imaging condition to bring it into the electroluminescence state. S41 is an initialization process,
Parameters and the initial position movement of the collimator lens driving device 16 are performed for the subsequent processing. S42 and S47 are data processing for determining the adjustment state of the collimator lens 3 using the brightness difference information.

In step S42, a scanning start command is sent to the collimator lens driving device 16 to scan the position of the collimator lens 3. Here, the same synchronization process is performed between the collimator lens driving device 16 and the imaging device 13 as in the example for the optical head (type 1) without the aspect ratio correction optical system. In S44, a region near the light emitting point is extracted.

The maximum luminance value is used for the search for the light emitting point as in the position adjustment of the light emitting element 2. Then, the region near the detected light emitting point is extracted. The vicinity area is defined in the same manner as the example for the optical head (type 1) without the aspect ratio correction optical system.

In S45, the brightness difference information is calculated as shown in FIG. 9 with the brightness difference between the pixels adjacent in the horizontal direction of the image as the horizontal component and the brightness difference between the images adjacent in the vertical direction as the vertical component. Both aspect ratio correction optical systems 19 act on the horizontal component,
Different characteristics as shown in FIG. 11 are exhibited depending on the astigmatic difference in the light emitting device.

In this example, the aspect ratio correction optical system 19
In the light emitting element image picked up due to the presence of, the lateral magnification is affected, and the lateral magnification is low. That is,
Since the magnification is lower than that in the vertical direction, the resolution of the brightness difference information is also low, and the sensitivity due to the position of the collimator lens 3 is low. Therefore, as shown in FIG. 11, the horizontal component of the brightness difference information changes more than the vertical component. Is getting smaller.

In order to utilize such a difference in characteristics, the ratio of each component of the brightness difference information is calculated in S46, and the above-mentioned predetermined value is compared and the position of the collimator lens 3 is scanned until they match with each other, S43. ~ The process of S46 is performed. However, since the ratio of each component shows the characteristic shown on the lower side of FIG. 11, there may be two positions of the collimator lens 3 where the ratio of each component of the brightness difference information has the same value. Therefore, the position of the collimator lens 3 is determined by using any value of the brightness difference information.

For example, paying attention to a vertical component having high sensitivity, even if the ratio has the same value, the vertical component has different values. Therefore, as shown by the up arrow in FIG. 11, the two values of the vertical component at the position of the collimator lens 3 where the ratio has the same value are compared, and the one with the larger value which is considered to be more in focus is compared. To adopt.

The above processing is summarized as follows. First, after the start of processing, initialization processing is performed (S41), and scanning of the collimator lens position is started (S42). In this case, the collimating lens driving device 16 and the light emitting element driving device 17 are driven by the control information from the image processing device 14 to start scanning of the light emitting element 2 and the collimating lens 3.

Next, an image of the end face of the light emitting element is acquired from the image pickup device and stored in the memory (image memory 23 and work memory 24).
(S43). Next, the region near the light emitting point is extracted (S44), and the brightness difference information is calculated for each component (S4).
5). Next, it is determined whether or not the ratio of the brightness difference information of each component matches a predetermined value (S46). If they do not match, the process proceeds to S43. If they match, the collimating lens position scanning is stopped (S47), This process ends.

(Additional Remarks) In addition to the above description, the following constitutions will be remarked.

(Supplementary Note 1) An infinity optical system composed of a collimator lens in the optical head, an image forming lens having a focal length longer than that of the collimator lens, and an image formed by the image forming lens. An imaging device, an illumination system including an illumination device that illuminates a light emitting element in the optical head with illumination light for imaging, an image processing device that captures an image from the imaging device and performs image processing, and the image processing The image processing device includes a collimator lens driving device that drives the collimator lens position based on image information processed by the device, and the image processing device is a light-emitting element image of an optical head captured in a state where illumination light is emitted by the illumination system. From the above, the minimum range necessary for image processing for adjusting the collimating lens position of the optical head by the collimating lens driving device An optical head adjusting apparatus characterized by comprising a calculating means for calculating a luminance difference information at a certain light-emitting point region.

(Supplementary Note 2) In the image processing apparatus, an optical head having an optical element for aspect ratio correction is used.
On the light emitting element image, the ratio of the orthogonal components of the brightness difference information in the area near the light emitting point, which is the minimum range necessary for image processing,
It is characterized in that it is provided with a computing means for computing information for controlling the astigmatism by driving the collimating lens by the collimating lens driving device by adjusting to a predetermined value. ) The optical head adjusting device described above.

(Supplementary Note 3) In order to emphasize the light emitting point, the image processing apparatus uses the brightness difference information obtained from the light emitting point vicinity area on the excited light emitting element image, which is the minimum range necessary for image processing. The optical head adjusting device according to (Additional remark 1) or (Additional remark 2), characterized in that the optical head adjusting device is provided with a calculating means for calculating information for adjusting the collimator lens position of the optical head by the collimator lens driving device. .

(Supplementary Note 4) In the image processing apparatus, in order to emphasize the light emitting point, the light emitting element is energized and the vicinity of the light emitting point which is the minimum range necessary for image processing on the light emitting element image in the excited state The optical device according to (Note 3), further comprising a computing unit that computes information for adjusting the collimating lens position of the optical head by the collimating lens driving device using the brightness difference information obtained from the area. Head adjustment device.

(Supplementary Note 5) Since the image processing apparatus emphasizes the light emitting point without energizing the light emitting element, the minimum necessary for image processing on the light emitting element image excited by the irradiation light from the illumination device. Using the brightness difference information obtained from the area near the light emitting point, which is the range of 1), the collimator lens driving device is provided with arithmetic means for calculating information for adjusting the collimator lens position of the optical head. (Appendix 3) The optical head adjusting device according to item 3.

(Supplementary Note 6) The image processing apparatus is characterized by having a function of detecting a region near the light emitting point of the light emitting element, which is a minimum range necessary for image processing, by template matching. 1) The optical head adjusting device as described above.

In this case, it has a function to be used when the optical head of the type 1 is provided, and provides a function to be used for extracting the light emitting point vicinity region. Further, even when the position of the light emitting point changes on the image due to the movement of the light emitting element or the collimating lens, it is possible to accurately search for the light emitting point by applying the pattern search method by template matching. The difference information can be calculated easily and with high accuracy.

(Supplementary Note 7) The image processing apparatus is characterized in that it has a function of detecting a region in the vicinity of a light emitting point of a light emitting element, which is a minimum range necessary for image processing, based on a maximum luminance value ( The optical head adjusting device according to attachment 1).

In this case, it has a function to be used when the optical head of the type 2 is provided, and provides a function to detect a region near the light emitting point. Further, even when the position of the light emitting point changes on the image due to the movement of the light emitting element or the collimating lens, it is possible to accurately search for the light emitting point by applying the pattern search method by the maximum brightness search. The brightness difference information can be easily calculated with high accuracy.

(Supplementary Note 8) In the image processing apparatus, when two collimator lens positions having the same ratio of the orthogonal components (horizontal component and vertical component) of the luminance difference information can be taken, one of the orthogonal components can be taken. The optical head adjusting device according to (Appendix 2), which has a function of adjusting the collimator lens to a desired position by using the value of.

In this case, it has a function used when it has the type 2 optical head and provides a function of adjusting the collimator lens to a desired position. That is, even if there are two collimator lens positions where the ratio of the orthogonal component (horizontal component and vertical component) of the brightness difference information can be the same, by using either one of the orthogonal components, the collimator lens can be obtained. Can be adjusted to a desired position.

[0141]

As described above, the present invention has the following effects.

(1): In claim 1, an infinity optical system composed of a collimating lens in the optical head and an image forming lens, an image pickup device for picking up an image formed by the image forming lens, The image processing device includes an illumination system including an illumination device, an image processing device, and a collimator lens driving device. The image processing device drives the collimator lens from the light emitting element image of the optical head captured in a state where the illumination light is emitted by the illumination system. The apparatus is provided with a calculating means for adjusting the position of the collimator lens of the optical head, for calculating the brightness difference information in the light emitting point vicinity area which is the minimum range necessary for image processing.

Therefore, since the laser beam after passing through the collimator lens is observed, it is possible to adjust the position of the collimator lens before attaching the objective lens. Further, in the conventional example, in order to image the laser beam after passing through the objective lens, it is necessary to search for a beam spot of 1 μm or less, and the tact time increases, but in the present invention, the laser beam before being focused is collected. The tact time can be shortened because an image of the light emitting element is captured.

(2): According to a second aspect of the present invention, the image processing apparatus has an optical head having an optical element for aspect ratio correction, and emits light within a minimum range necessary for image processing on the light emitting element image. Information for controlling the astigmatism is calculated by driving the collimator lens by the collimator lens driving device by adjusting the ratio of the orthogonal component of the luminance difference information in the area near the point to a predetermined value determined in advance. Equipped with calculation means.

Therefore, with respect to the optical head having the aspect ratio correction optical system, the ratio of the orthogonal component (horizontal component and vertical component) of the luminance difference information near the light emitting point on the light emitting element image is adjusted to a predetermined value. This makes it possible to control astigmatism.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the luminance difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

(3) In the third aspect, the image processing apparatus obtains from the light emitting point vicinity area which is the minimum necessary range for image processing on the excited light emitting element image in order to emphasize the light emitting point. A calculation unit is provided for calculating information for adjusting the collimator lens position of the optical head by the collimator lens driving device using the brightness difference information.

In this case, since the light emitting points in the LED light emitting state and the photoluminescence light emitting state are observed, pattern search methods such as template matching and maximum brightness search are applied even when the light and shade difference in the vicinity of the light emitting point is not sufficient. ,
It becomes possible to search for the light emitting point with high accuracy, and the brightness difference information can be easily calculated with high accuracy.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the brightness difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

(4): According to claim 4, the image processing device energizes the light emitting element in order to emphasize the light emitting point, and within the minimum necessary range for image processing on the light emitting element image in the excited state. A calculation means is provided for calculating information for adjusting the collimating lens position of the optical head by the collimating lens driving device, using the brightness difference information obtained from a region near a certain light emitting point.

In this case, since the light emitting points in the LED light emitting state and the photoluminescence light emitting state are observed, pattern search methods such as template matching and maximum brightness search can be applied even when the light and shade difference in the vicinity of the light emitting point is not sufficient. ,
It becomes possible to search for the light emitting point with high accuracy, and the brightness difference information can be easily calculated with high accuracy.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the brightness difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

(5) According to the fifth aspect, the image processing apparatus emphasizes the light emitting point without energizing the light emitting element. Therefore, the image processing is performed on the light emitting element image excited by the irradiation light from the illumination device. A calculation unit is provided for calculating information for adjusting the collimator lens position of the optical head by the collimator lens driving device, using the brightness difference information obtained from the light emitting point vicinity region which is the above minimum necessary range.

In this case, since the light emitting point in the LED light emitting state or the photoluminescence light emitting state is observed, the pattern searching method such as the template matching or the maximum brightness search is applied even when the light and shade difference near the light emitting point is not sufficient. ,
It becomes possible to search for the light emitting point with high accuracy, and the brightness difference information can be easily calculated with high accuracy.

Further, since the ratio of the orthogonal component (horizontal component and vertical component) is used for the brightness difference information, when the light and shade of the light emission pattern due to the LED light emission intensity or the photoluminescence light emission intensity varies depending on the individual light emitting elements. Also, even when the amount of illumination light changes with time, these are canceled out, and stable adjustment becomes possible.

(6): According to the first to fifth aspects, the infinity optical system including the collimator lens in the optical head and the imaging lens having a focal length longer than that of the collimator lens is formed, whereby Since the lateral magnification and the vertical magnification can be enlarged for observation, the resolution of the brightness difference information of the image in which the position of the collimator lens is observed is high, and the adjustment can be performed accurately.

Since the beam after passing through the objective lens is not observed, the field of view can be set wide. Further, a complicated optical system for expanding the beam spot after passing through the objective lens is not required, and the optical axes of the optical head and the image pickup system can be easily aligned.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of an optical head adjusting device in an embodiment of the present invention, FIG.
FIG. B is an explanatory diagram of the type 2 configuration.

FIG. 2 is an explanatory diagram of an image processing apparatus according to an embodiment of the present invention, FIG. A is a configuration diagram of the image processing apparatus, and FIG. B is a diagram showing a processing outline.

FIG. 3 is an explanatory diagram of an apparatus according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of an arrangement example according to the embodiment of the present invention.

FIG. 5 is a schematic diagram (part 1) of a light emitting element image according to an embodiment of the present invention, in which FIG.

6A and 6B are schematic views (No. 2) of a light emitting element image according to an embodiment of the present invention, where FIG. 6A is a light emitting element image when the light emitting point is in focus, and FIG. It is a figure which shows the light emitting element image when it is not.

FIG. 7 is a diagram showing an example of the relationship between the collimator lens position and luminance difference information in the embodiment of the present invention, FIG. A showing Example 1, B showing Example 2 and C showing Example 3. is there.

FIG. 8 is an explanatory diagram of luminance difference information according to the embodiment of the present invention.

FIG. 9 is a diagram showing luminance difference information in the case of an optical head including an aspect ratio correction optical system according to an embodiment of the present invention.

FIG. 10 is a diagram showing a relationship between a collimator lens position and astigmatism in the embodiment of the present invention, FIG. A is a relationship between the collimator lens position and the objective lens position, and B is a collimator lens position and the astigmatism. It is a figure which shows the relationship with an aberration.

FIG. 11 is a diagram showing a relationship between collimator lens position and luminance difference information in the embodiment of the present invention.

FIG. 12 is a diagram showing a relationship between astigmatism and luminance difference information in the embodiment of the present invention.

FIG. 13 is a processing flowchart at the time of rough adjustment of the collimator lens and adjustment of the light emitting element in the optical heads of types 1 and 2 in the embodiment of the present invention.

FIG. 14 is a processing flowchart at the time of fine adjustment of the collimator lens in the type 1 optical head according to the embodiment of the present invention.

FIG. 15 is a processing flowchart at the time of fine adjustment of the collimator lens in the type 2 optical head according to the embodiment of the present invention.

FIG. 16 is a configuration diagram of a conventional optical head adjustment device.

[Explanation of symbols]

1 Optical head 2 light emitting element 3 Collimating lens 4 mirror 5 Objective lens 6 Light receiving element 11 Pseudo medium 12 Imaging lens 13 Imaging device 14 Image processing device 15 Lighting equipment 16 Collimating lens drive 17 Light emitting device driving device 19 Aspect ratio correction optical system 21 CPU (Central Processing Unit) 22 Program Storage Means 23 Image memory 24 work memory 26 Fixed optical system 27 Movable optical system 28 Imaging system 31 camera 32 half mirror 33 monitors

Continued front page    F term (reference) 5D117 AA02 CC07 HH01 KK13 KK17                 5D119 AA38 BA01 EB03 EC02 FA05                       JA02 JC07 PA01                 5D789 AA38 BA01 EB03 EC02 FA05                       JA02 JC07 PA01

Claims (5)

[Claims] 1. An infinity optical system composed of a collimator lens in an optical head, and an imaging lens having a focal length longer than that of the collimator lens, and an imaging device for picking up an image formed by the imaging lens. An illumination system including an illumination device that illuminates the light emitting element in the optical head with illumination light for imaging; an image processing device that captures an image from the imaging device and performs image processing; With a collimator lens driving device that drives the collimator lens position based on the processed image information, the image processing device, from the light emitting element image of the optical head imaged in a state where illumination light is irradiated by the illumination device,
It is characterized by further comprising a calculating means for calculating the brightness difference information in the light emitting point vicinity region which is a minimum range necessary for image processing for adjusting the collimator lens position of the optical head by the collimator lens driving device. Optical head adjustment device. 2. The image processing apparatus, wherein an optical head having an optical element for aspect ratio correction is used, a luminance difference in a light emitting point image near a light emitting point which is a minimum range necessary for image processing on a light emitting element image. By adjusting the ratio of the orthogonal component of the information to a predetermined value, the collimating lens driving device drives the collimating lens to calculate information for controlling the astigmatism. The optical head adjusting device according to claim 1, wherein: 3. The image processing device, in order to enhance a light emitting point, on an excited light emitting element image,
Using the brightness difference information obtained from the vicinity of the light emitting point, which is the minimum range necessary for image processing, a calculating means for calculating information for adjusting the collimating lens position of the optical head by the collimating lens driving device is provided. The optical head adjusting device according to claim 1, wherein the optical head adjusting device is provided. 4. The image processing apparatus, in order to emphasize a light emitting point, energizes a light emitting element and detects a light emitting element from an area near a light emitting point, which is a minimum range necessary for image processing, on a light emitting element image in an excited state. 4. The optical head adjusting device according to claim 3, further comprising a computing unit that computes information for adjusting the collimating lens position of the optical head by the collimating lens driving device using the obtained brightness difference information. . 5. The image processing apparatus emphasizes a light emitting point without energizing a light emitting element, and therefore, a minimum range necessary for image processing on a light emitting element image excited by irradiation light from a lighting device. 7. A calculation means for calculating information for adjusting the collimating lens position of the optical head by the collimating lens driving device by using the brightness difference information obtained from the light emitting point vicinity area is provided. 3. The optical head adjusting device according to item 3.