JP2002251753A - Error detecting method, error detector, return light flux division optical element, optical pickup device and optical information processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an error detecting method and its device efficient for minimization of an optical pickup device. SOLUTION: In this method to detect a focusing error and a tracking error based on a return light flux in the optical pickup device to perform one or more of recording, reproduction and deletion of information to an optical information recording medium to generate an interference pattern in a return light flux, the return light flux FX to move toward a return light detecting part is made incident on a return light flux division optical element 10, optically divided into a first light flux part FX1 in which density of the interference pattern in the zero-th order light of the return light flux does not change, second and third light flux parts FX2, FX3 in which the density of the interference pattern reciprocally changes by the return light flux division optical element 10, the focusing error is detected by using the first light flux part FX1 and the tracking error is detected by using the second and third light flux parts FX2, FX3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical pickup device, an error detection method / error detection device in the optical pickup device, a return beam splitting optical element used in the error detection device, and an optical information processing device using the optical pickup device.

[0002]

2. Description of the Related Art Optical pickup devices are mounted on various optical information processing devices such as CD players and DVD players, and are becoming indispensable in modern life. Since the optical pickup device is mounted on such various devices, there is a strong demand for downsizing the optical pickup device.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an error detecting method and apparatus effective for downsizing an optical pickup device.

[0004]

An error detection method according to the present invention is described in an optical pickup apparatus for performing at least one of recording, reproducing, and erasing of information on an optical information recording medium that causes an interference pattern in a return light beam. How to detect focusing and tracking errors based on light flux "
It is.

The “return light beam” is a light beam reflected by the recording surface of the optical information recording medium. The present invention is directed to an optical information recording medium that generates an "interference pattern in a return light beam". The interference pattern in the return light beam is generated by extremely minute regular irregularities on the recording surface.

That is, if there are regular minute irregularities on the recording surface, diffraction occurs in the reflected light, and the reflected light portion reflected as 0-order light and the reflected light portion reflected as + 1-order light interfere with each other. Thus, the first pattern is formed, and the reflected light portion reflected as the zero-order light and the reflected light portion reflected as the minus first light interfere with each other to form the second pattern.

The "density" or brightness of these first and second patterns changes reciprocally, and when one pattern becomes bright, the other pattern becomes dark. For example, the "push-pull method" widely known as tracking control
Is the "reciprocal change in density" of the first and second patterns
Is used to generate a tracking error signal.

[0008] For example, CD-R
As in the case of the OM, "when the track is formed by a row of concave or convex pits", as in the case of a CD-R, "when the track is formed as a groove on both sides thereof", In the case where the pit is formed with a depth in the track portion formed as described above, the interference pattern is generated in the return light beam.

The error detecting method according to the first aspect has the following features. That is, the return light beam directed to the return light detecting unit is made incident on the return light beam splitting optical element, and the return light beam splitting optical element causes the first light beam of the interference pattern in the zero-order light of the return light beam to remain unchanged (brightness). Optically divided into a portion and second and third light flux portions where the density of the interference pattern changes reciprocally.

Then, a focusing error is detected using the first light beam portion, and a tracking error is detected using the second and third light beam portions.

The "return light detecting unit" is a device portion (of the optical pickup device) that detects at least a part of the return light beam in order to detect a focusing error and a tracking error.

[0012] The "tracking error detection" in the error detection method according to the first aspect of the present invention is a method of "tracking error detection" in which the second and third light beam portions are received by light receiving portions that are separate from each other, and the "push" is performed by a difference in light receiving amount between the light receiving portions. Detect by "pull method"
(Claim 2) Further, each of the second and third light flux portions is received by a light receiving portion divided into two in a direction parallel to the track, and detected by a “phase difference detection method”. 3) It is also possible to further separate each of the second and third light flux portions into two in the direction parallel to the track by the return light beam splitting optical element, and separate each of the separated light fluxes by a separate light receiving unit. (4) The light is selectively received and detected by performing a predetermined operation on the output of each light receiving section.
You can also.

[0013] In the "detection of a focusing error" in the error detecting method according to the first aspect of the present invention, the returning light beam splitting optical element separates the first light beam portion into two focused light beams having different focusing distances. Detection is performed by a double beam size method using two focused light beams (claim 5).
Further, it is also possible to generate astigmatism in the first light beam portion by the return light beam splitting optical element and detect the astigmatism by the astigmatism method (claim 6).

The "condensing distance" is the "distance from the return beam splitting optical element to the condensing position" of each of the separated condensed light beams.
Say

In the error detecting method according to the fifth aspect, each of the light receiving units for receiving the two converged light beams is divided into two in a direction orthogonal to the track, and the track offset amount is determined based on the output from one of the light receiving units. It can be detected (claim 7).

Further, in the error detection method according to the present invention, the four-divided light receiving portion for receiving the first light beam portion provided with astigmatism is provided with two light beams in a direction orthogonal to the track.
The track offset amount can be detected based on the difference between the outputs of the two light receiving surfaces (claim 8).

In these error detection methods, the tracking error is detected by the following method.
The method can be performed by any one of the above-described claims 2 or 3 or 4.

The return light beam splitting optical element according to claim 9 is
A return beam splitting optical element used for implementing the error detection method according to claim 1, having the following features.

That is, the return light beam splitting optical element is integrally formed of a transparent material, and the return light beam is converted into a first light beam portion where the density of the interference pattern in the zero-order light does not change, and the density of the interference pattern changes reciprocally. The first and second light beam portions are configured to be optically split, and at least the portion that splits the first light beam portion has a lens function of positive power.

In the return light beam splitting optical element according to the ninth aspect, the portion for splitting the second and third light beam portions may have no lens function (claim 10).
The portions that divide the second and third light flux portions may also have “the same positive power lens action” (claim 11).

In the return light beam splitting optical element according to the ninth aspect, the portion for splitting the first light beam portion is "two lens surface portions arranged in a direction parallel to the track".
The positive power of each of these lens surface portions can be made different so that the first light beam portion can be divided into two focused light beams having different focusing distances from each other (claim 12). With this configuration, it is possible to detect a focusing error by the double beam size method using two focused light beams having different focused distances.

According to a ninth aspect of the present invention, the return light beam splitting optical element has an anamorphic lens surface for splitting the first light beam portion, and has a lens function of giving astigmatism to the first light beam portion. (Claim 13).

According to a ninth aspect of the present invention, the return light beam splitting optical element further divides each of the portions for splitting the second and third light beam portions into two lens surface portions for separating each light beam portion in a direction parallel to the track. The configuration can be as follows (claim 14).

In this case, the portion that divides the first light beam portion is, as in the case of the twelfth aspect, "two lens surface portions arranged in a direction parallel to the track, and the positive The power may be made different and the first light beam portion may be divided into two converged light beams having different focusing distances from each other. Alternatively, as in the case of claim 13, the anamorphic lens surface may be used. It has a lens function of giving astigmatism to one light flux portion. "

The return beam splitting optical element may be constituted by a "reflective element" in addition to a transparent element as described in the above-mentioned claims 9 to 14. In addition, the return light beam splitting optical element can be constituted not only by a shape-imparting condensing lens, but also by an optical element having a condensing function such as a grating or a hologram element, or can be constituted by combining them.

According to a fifteenth aspect of the present invention, there is provided an error detecting apparatus, comprising: an optical pickup device that performs at least one of recording, reproducing, and erasing of information on an optical information recording medium that causes an interference pattern in a returning light beam. "A device for detecting a focusing error and a tracking error", comprising a return beam splitting optical element, a light receiving unit, a focusing error signal generating unit, and a tracking error signal generating unit.

The "return light beam splitting optical element" receives the return light beam directed to the return light detection unit, and returns the return light beam to the return light beam.
A first light beam portion where the density of the interference pattern in the next light does not change, and a second light beam portion where the density of the interference pattern changes reciprocally.
And a third light beam portion.

The "light receiving means" has a plurality of light receiving portions for receiving each light beam split by the return light beam splitting optical element.

"Focusing error signal generating means"
Generates a focusing error signal using the photoelectric conversion output of the light receiving unit that receives the first light beam portion.

"Tracking error signal generating means"
A tracking error signal is generated using the photoelectric conversion output of the light receiving unit that receives the second and third light flux portions.

According to a fifteenth aspect of the present invention, there is provided an error detecting apparatus using the above-mentioned tenth or eleventh aspect as the return beam splitting optical element, and using the two light receiving means for receiving the second and third light flux portions. Having a light-receiving part of
The tracking error signal generating means may be configured to generate a push-pull tracking error signal using the photoelectric conversion outputs of the two light receiving units.
(Claim 16) Claim 1 as a return light beam splitting optical element.
0 or 11 or 14 is used as the light receiving means, "a part where the light receiving portions of the second and third light beams have light receiving portions separated into two in a direction parallel to the track" is used. It is also possible to employ a configuration in which the tracking error signal of the phase difference detection method is generated by the tracking error signal generating means using the photoelectric conversion outputs of the “four light receiving units that receive the second and third light flux portions”. (Claim 17).

The error detecting device according to the fifteenth aspect further employs the return light beam splitting optical element according to the twelfth aspect, and uses the light receiving means as "a first focused light beam separated into two focused light beams having different focusing distances from each other." The light receiving portion of each light beam portion is a three-divided light receiving portion that is divided into three in a direction parallel to the track ”, and the focusing error signal generating means outputs the photoelectric conversion output of each of the three divided light receiving portions. To generate a focusing error signal of the double beam size method (claim 18). The return light beam splitting optical element according to claim 13 can be used, and "light astigmatism" can be used as the light receiving means. Is given by dividing the light receiving surface into four parts by dividing lines that are at 45 degrees to the track direction and that are orthogonal to each other. A focusing error signal is generated by the focusing error signal generating means by using the photoelectric conversion output of the four-divided light receiving unit (claim 19). Can also.

[0033] The error detecting device according to the fifteenth aspect also includes:
The return light beam splitting optical element according to claim 12 is used as a light receiving means, wherein a portion of each of the first light beam portions separated into two focused light beams having different condensing distances from each other receives the respective focused light beams in a track. A six-divided light receiving unit divided into three in the parallel direction and divided into two in the track orthogonal direction ”, and the focusing error signal generating means uses the photoelectric conversion output of each of the six divided light receiving units to generate a double beam size. In addition to generating a focusing error signal, a track offset amount signal can be generated (claim 20). Further, the return light beam splitting optical element according to claim 13 can be used as the light receiving means. "A part that receives the first light beam part provided with astigmatism is divided at 45 degrees to the track direction and orthogonal to each other. And a focusing error signal generating means for generating a focusing error signal of the astigmatism method using the photoelectric conversion output of the four-divided light receiving unit. It may be configured to generate a track offset amount signal (claim 21).

In the error detecting device according to claim 18 or 19 or 20 or 21, the generation of the tracking error signal can be performed in the same manner as in the error detecting device according to claim 16 or 17.

An optical pickup device according to a twenty-second aspect is an optical pickup device that performs at least one of recording, reproducing, and erasing of information on an optical information recording medium that causes an interference pattern in a return light beam. An error detecting device according to claim 15 is used as a device for detecting a focusing error and a tracking error based on the above.

In the optical pickup device according to the twenty-second aspect, the error detecting device according to any one of the sixteenth to nineteenth aspects can be used (claim 23). It can also be used (claim 24).

The optical information processing apparatus according to the present invention is an "optical information processing apparatus which performs at least one of recording, reproducing and erasing of information on a disk-shaped optical information recording medium which causes an interference pattern in a return light beam". , A holding unit, a driving unit, an optical pickup device, and a displacement driving unit.

The "holding unit" is set with an optical information recording medium. The “driving unit” rotationally drives the optical information recording medium set in the holding unit. 23. The optical pickup device according to claim 22, wherein the optical pickup device performs at least one of recording, reproducing, and erasing on the optical information recording medium set in the holding unit.
Those described in any one of 24 are used.

The "displacement driving means" drives the optical pickup device to be displaced in the radial direction of the optical information recording medium.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An outline of an optical pickup device will be described with reference to FIG. In FIG. 13A, a divergent light beam emitted from a semiconductor laser 1 as a light source is converted into a substantially parallel light beam by a collimator lens 2, and a light beam cross-sectional shape is formed by a beam shaping element 3 combining a pair of prisms. Polarized beam splitter 4 shaped into a substantially circular shape
Through the 波長 wavelength plate 5 and incident on the objective lens 6, converted into a focused light beam by the action of the objective lens 6 and incident on the optical information recording medium 9, transmitted through the transparent substrate and recorded. The light is focused on the surface 9A as a light spot.

The light beam reflected on the recording surface of the optical information recording medium 9 becomes a “return light beam”, passes through the objective lens 6 and is returned to a substantially parallel light beam, and is transmitted through the quarter-wave plate 5 to the polarization beam splitter 4. Then, the light is reflected by the polarization beam splitter 4 and enters the return light detection unit 8.

The return light detector 8 detects a focusing error and generates a focusing error signal based on the return light flux, and detects a tracking error to generate a tracking error signal.

The focusing error signal and the tracking error signal are sent to a control unit (not shown), and the control unit controls the actuator 7 in accordance with the error signals.
The objective lens 6 is displaced and driven, and focusing control is performed by adjusting the position of the objective lens 6 in the optical axis direction so that the light spot is always focused on the recording surface, and the objective lens 6 is moved in a direction orthogonal to the track. The light spot follows the track by position adjustment (tracking drive).

In this way, any of the recording, reproduction, and erasure of information is performed on the optical information recording medium 9 while performing the focusing control and the tracking control. In addition,
In the example of FIG. 13, when the reproduction is performed, the return light detecting unit 8
A reproduction signal is generated based on the return light beam received by the.

FIG. 13B is a diagram for explaining the occurrence of an interference pattern in the return light beam. As described above, the interference pattern of the return light beam is caused by minute irregularities on the recording surface of the optical information recording medium. In the example shown in FIG. 13B, the unevenness of the recording surface is due to “a step between a track formed as a groove and portions on both sides thereof”. Since the interval between adjacent tracks is extremely small, light reflected by the recording surface 9A undergoes diffraction.

As shown in FIG. 1B, the reflected light beam is divided into a zero-order light Fx0, a + 1st-order light Fx + 1, and a -1st-order light Fx-1 by diffraction. Then, interference occurs at a portion PT1 where the 0th-order light Fx0 and the + 1st-order light Fx + 1 overlap and at a portion PT2 where the 0th-order light Fx0 and the -1st-order light Fx-1 overlap.

The portions PT1 and PT2 where interference occurs differ in density (light intensity) from the other portions due to interference, but this density changes reciprocally between the portions PT1 and PT2.
As one density becomes higher (darker), the other density becomes lower (brighter). The return light beam in which interference has occurred in this way is taken in by the aperture of the objective lens having the “zero-order light intensity” and guided to the return light detection unit 8.

FIG. 1 is a diagram for explaining an embodiment of an error detecting device used in the return light detecting section. In FIG. 1A, reference sign FX indicates “return light beam”. The cross section of the return beam FX is shown. Return beam F
X has an interference pattern due to the above-described interference. The returning light beam is substantially “parallel light beam”.

In this interference pattern, the reference numeral FX1 indicates a "portion where the density of the return light flux in the zero-order light does not change", and the reference numeral FX2 and FX3 indicates "the density of the interference pattern changes reciprocally." Part ".

As described above, the return light beam FX having the interference pattern in the light beam cross section first receives the return light beam splitting optical element 1.
Incident at 0. The return beam splitting optical element 10 is integrally formed of a transparent material such as glass or plastic. The return light beam splitting optical element 10 is a transparent parallel flat plate as a whole, and has a flat surface on the side where the return light beam FX is incident.

As shown in the drawing, four lens surface portions DL1, DL2, DL3 and DL4 are formed on the exit side of the return beam splitting optical element 10 at the portion where the return beam FX exits. Lens surface portions DL1, DL2, DL3, DL
4 have positive power, but their optical axes are separated from each other. The lens surface portions DL3 and DL4 have the same power, respectively, and mainly act on the light beam portions FX2 and FX3 in the return light beam FX, and the lens surface portions DL1 and DL2 have different powers from each other. The lens function is mainly applied to the light flux portion FX1.

Since the optical axes of the lens surface portions DL1 to DL4 are separated from each other as described above, the return light beam transmitted through the return light beam splitting optical element 10 is separated from the light beam portion transmitted through each lens surface. Will be.

Since the lens surface portions LD1 and LD2 have "positive powers different from each other", these lens surface portions L1 and LD2 have different positive powers.
The light flux transmitted through D1 and LD2 is separated into two focused light fluxes having different focusing distances.

That is, the return light beam splitting optical element 10 is integrally formed of a transparent material, and the portion where the return light beam FX directed to the return light detection unit enters the return light beam FX is converted into the density of the interference pattern in the zero-order light. It is optically split into a first light beam portion that does not change (mainly the zero-order light portion FX1) and second and third light beam portions (mainly the light beam portions FX2 and FX3) in which the density of the interference pattern changes reciprocally. Thus, the portions (the lens surface portions DL1 and DL2) that divide the first light beam portion have a lens function of positive power.

The portion of the return light beam splitting optical element 10 that splits the first light beam portion is composed of two lens surface portions DL1 and DL2 arranged in a direction parallel to the track.
The positive power of each of the lens surface portions DL1 and DL2 is different, and the first light beam portion (mainly the zero-order light portion FX
1) is separated into two focused light beams having different focusing distances.

In FIG. 1A, reference numeral 12 denotes "light receiving means". The light receiving means 12 has a plurality of light receiving sections PD1, PD2, PD3, PD4 as shown in the figure. The light receiving portions PD1 and PD2 correspond to the lens surface portions DL1 and DL2 in the return light beam splitting optical element 10, and are separated by the lens surface portions DL1 and DL2, respectively (condensed light beams having different light condensing distances). Is received.

The light receiving portions PD3 and PD4 correspond to the lens surface portions DL3 and DL4 of the return light beam splitting optical element 10, and the second and third light beam portions (condensed light beams) divided by the lens surface portions DL3 and DL4. ) Is received. The output of each light receiving portion of the light receiving means 12 is input to the calculating means 14.

FIG. 1B shows the state of each light receiving section in the light receiving means 12. The light receiving unit PD1 has light receiving surfaces A, B, and C arranged in a direction parallel to the track (the vertical direction in the drawing).
And output signals: a, b, c from the respective light receiving surfaces A, B, C
Is output. The light receiving section PD2 is in a direction parallel to the track.
The light receiving surfaces D, E, and F are arranged in the vertical direction in the figure, and output signals: d, e, and f are output from the light receiving surfaces D, E, and F, respectively.

The light receiving section PD3 has a single light receiving surface G and outputs an output signal: g. The light receiving section PD4 has a single light receiving surface H
And outputs an output signal: h.

The light receiving means 12 includes the return light beam splitting optical element 1
The two focused light fluxes having different focusing distances separated by the 0 lens surface portions DL1 and DL2 are arranged at “positions where the light flux cross sections are substantially the same”. That is, the light receiving unit PD
The light beam incident on the light receiving unit PD1 is in the state of “light is being collected”, and the light beam incident on the light receiving unit PD1 is in the “divergent state after light collection”. Since the lens surface portions DL3 and DL4 have the same power, the cross-sectional sizes of the light beams incident on the light receiving units PD3 and PD4 are substantially the same.

Therefore, the light receiving sections PD1 to PD4
Are input to the calculating means 14 and the calculating means 1
4, the tracking error signal: TE as "TE =
gh ”, the signal is a tracking error signal by the well-known push-pull method.

The calculating means 14 sets "TF = (a + c + e)-(b
+ D + f) ", this signal is a focusing error signal by the well-known" double beam size method ".

Therefore, focusing control and tracking control can be executed by these error signals. When reproducing information, "a + b + c + d + e + f"
An operation of “a + b + c + d + e + f + g + h” is performed to obtain a reproduced signal.

FIG. 2 is a diagram for explaining another embodiment of the error detecting device. (A) shows the return light beam splitting optical element 20. The return light beam splitting optical element 20 is, like the return light beam splitting optical element 10 described above, based on a transparent parallel flat plate, and has a surface on the side from which the return light beam exits as shown in FIG.
As shown in (b), the lens surface portions DL1 ', DL2',
DL3 'and DL4' are formed.

Each of the lens surface portions DL1 'to DL4' has a positive power. Lens surface portion DL3 ', DL4'
Are arranged in a direction perpendicular to the tracks and have equal power. These lens surface portions DL3 ', DL4'
Divides the return light beam FX into a second light beam portion F2 and a third light beam portion F3 in which the density of the interference pattern changes reciprocally, and makes these light beams incident on the light receiving means as condensed light beams.

The "light receiving means" is the light receiving means 1 shown in FIG.
2 and the light receiving unit PD1 as shown in FIG.
To PD4, and outputs from these light receiving units as shown in the figure:
a to h are output. Lens surface portions DL1 ', DL2'
Has positive powers different from each other, and separates the first light flux portions in which the density of the interference pattern in the zero-order light does not change as two focused light fluxes F1-1 and F1-2 having different focusing distances.

When "the light spot is located on the track in the focused state", the detection pattern on the light receiving units PD1 to PD4 (the cross section of the light beam on the light receiving means) is as shown in FIG. 2C.

Therefore, similarly to the embodiment of FIG. 1, the outputs: a to h of the light receiving sections PD1 to PD4 are input to a not-shown calculating means (the same as the calculating means 14 in FIG. 1). Tracking error signal: TE
Is calculated by calculating “TE = gh”, this signal is a tracking error signal by a well-known push-pull method.

Also, the calculating means sets the focusing error signal: TF as "TF = (a + c + e)-(b + d
+ F) ", this signal is a focusing error signal by the well-known double beam size method.

Therefore, focusing control and tracking control can be executed by these error signals. When reproducing information, for example, “a +
An operation of “b + c + d + e + f” can be performed to obtain a reproduced signal.

FIG. 3 shows only a characteristic portion of a modification of the embodiment shown in FIGS. The feature of this mode resides in "light receiving means". That is, in this embodiment, the light receiving means includes light receiving sections PD1, PD2 and PD3 'and P3.
D4 '.

The light receiving sections PD1 and PD2 are the same as those of the light receiving means in FIGS. Light receiving unit PD3 ', PD
4 ′ is “the light receiving surface is divided into two in the direction parallel to the track to obtain light receiving surfaces G1, G2 and light receiving surfaces H1, H2”.
It is. The light receiving surfaces G1, G2, H1, and H2 output outputs: g1, g2, h1, and h2, respectively.

The track of the optical information recording medium is a "pit row"
In the tracking control by the push-pull method, there is a problem that the tracking error signal is weakened depending on the depth of the pit. However, the light receiving means is configured as shown in FIG. By calculating the signal “TE = (g1 + h2) − (g2 + h1)”, a “tracking error signal of the phase difference detection method” can be generated.

This is a method for calculating the “change in the interference pattern of the diffracted light when the light spot hits the edge of the pit”. Even if the light receiving portion arrangement of the light receiving means is as shown in FIG. 3, in the case of an optical information recording medium having a step due to a track groove, TE = (g1 + g2) + (h1 + h2) and "tracking error signal by push-pull method" You can also get

Also in the embodiment shown in FIG. 3, the focusing error signal is based on the "double beam size method" and is calculated and calculated in the same manner as in the embodiment shown in FIGS.

FIG. 4 shows a modification of the embodiment shown in FIG. In this embodiment, the return beam splitting optical element 40 is
As shown, six lens surface portions DL1, DL2, DL3
-1, DL3-2, DL4-1, DL4-2, and the light receiving means 42 includes six light receiving units PD1, PD2, PD3-
1, PD3-2, PD4-1 and PD4-2.

The return light beam splitting optical element 40 includes two lens surface portions DL3-1 and DL3-1 in the direction parallel to the track, respectively, in the direction parallel to the track. DL3-2,
DL4-1 and DL4-2, and accordingly, the light receiving section of the light receiving means 12 is also divided into two light receiving sections PD3-1, PD3-2, PD4-1 and PD4-2. I have.

Therefore, the return light beam FX is split into six light beams by the return light beam splitting optical element 40 and received by the corresponding light receiving portion. Light receiving unit PD3-1, PD3-2, PD
4-1 and the output of PD 4-2 are set to g as in the case of FIG.
1, g2, h1, h2, the heterodyne signal “T
By calculating E = (g1 + h2)-(g2 + h1), a "tracking error signal of the phase difference detection method" can be generated, and TE = (g1 + g2) + (h1 + h).
As 2), a “tracking error signal by the push-pull method” can be obtained.

In each of the embodiments described above with reference to FIGS. 1 to 4, the detection of the focusing error is based on the “double beam size method”. Of course, the detection of the focusing error is not limited to the double beam size method. Below,
A case where the focusing error is detected by the “astigmatism method” will be described.

FIG. 5A shows a return beam splitting optical element used in this case. Return beam splitting optical element 50
Has three lens surface portions DL5, DL6, and DL7 long in a direction parallel to the track on one surface of a transparent parallel flat plate (the surface on the side where the return light beam exits toward the light receiving means).

Of these lens surface portions, lens surface portions DL5 and DL7 are the same as lens surface portions DL3 'and DL4' in return beam splitting optical element 20 shown in FIG. It is optically divided into second and third light flux portions whose densities change reciprocally "and condensed toward a light receiving unit for tracking error detection.

The lens surface portion DL6 divides the “first light beam portion where the density of the interference pattern in the zero-order light of the returned light beam does not change” from the returned light beam, and has a positive power. The power is different in the orthogonal direction, and “astigmatism” is given to the divided first light flux portion.

FIG. 5B shows the arrangement of the light receiving section in the "light receiving means". The light receiving means is a lens surface portion D
L5, DL6, and DL7, corresponding to the light receiving units PD5 and PD
6. It has PD7.

The second and third light receiving sections PD5 and PD7 are provided.
The light flux portion is incident as shown in the figure, and these incident states (detection patterns) are shown on the figure according to the defocus state (the image forming position of the light spot is closer to the objective lens than the recording surface).
It changes from middle (focused state) to below (the image forming position of the light spot is located on the back side of the recording surface).

When a tracking error occurs, the light receiving section P
Since the amounts of light received by D5 and PD7 change, a tracking error signal of the push-pull method: TE = q−r can be generated using the outputs: q, r of these light receiving units PD5, PD7.

On the other hand, the light receiving portion PD6 that receives the “condensed light beam with astigmatism”, which is the first light beam portion, has an angle of 45 degrees with respect to the track direction (the vertical direction in FIG. 5B). The light receiving surface is divided into four light receiving surfaces J, K, M, and N by dividing lines orthogonal to each other.

The output from each divided light receiving surface is represented by j,
Assuming that k, m, and n are used, a focusing error signal of the astigmatism method is used: TF = (j + k)-(m +
n) can be generated.

In this case, the light receiving surfaces of the light receiving sections PD5 and PD7 are divided into two in the “direction parallel to the track” as shown in FIG. 6, and the output from each divided light receiving surface is q1,
Assuming that q2, r1, and r2, the heterodyne signal “TE =
By calculating (q1 + r2)-(q2 + r1), a “tracking error signal by the phase difference detection method” can be generated, and a “tracking error signal by the push-pull method” can be obtained as TE = (q1 + q2) + (r1 + r2). it can.

Further, as in the embodiment shown in FIG.
Each of the lens surface portions of the return light beam splitting optical element 50 'that divide the second and third light beam portions from the return light beam is divided into two lens surface portions DL5- in a direction parallel to the track.
1, DL5-2 and DL7-1 and DL7-2, and the light receiving unit for tracking error detection is a light receiving unit P
Even if it is composed of D5-1, PD5-2, PD7-1, and PD7-2, "tracking error signal by phase difference detection method" and "tracking error signal by push-pull method" in the same manner as in FIG. Can be generated.

The generation of various error signals is performed by "calculating means (not shown) to which the output of each light receiving unit of the light receiving means is inputted".

To summarize each of the embodiments described above,
Each of the return light beam splitting optical elements 10, 20, 40, 50, 50 'used in each embodiment is integrally formed of a transparent material, and the return light beam FX is converted to the density of the interference pattern in the zero-order light. It is configured to optically divide into a first light beam portion that does not change and second and third light beam portions in which the density of the interference pattern changes reciprocally, and at least a portion that splits the first light beam portion ( The lens surface portions DL1, DL2, DL1 ', DL2', DL6) have a positive power lens function (claim 9).

The return light beam splitting optical elements 10, 20,.
In 50, the portions (the lens surface portions DL3, DL4, DL3 ', DL4', DL4) for dividing the second and third light flux portions
5, DL7) has a lens function of "same positive power" (claim 11).

In the return light beam splitting optical elements 10, 20, and 40, the portions that split the first light beam portion are two lens surface portions DL1, DL2 arranged in a direction parallel to the track.
2, DL1 'and DL2', each lens surface portion having a different positive power, and separates the first light beam portion into two focused light beams having different focusing distances from each other (claim 12).

The return optical split optical elements 50 and 50 '
Then, a portion that divides the first light beam portion (the lens surface portion D
L6) has a lens function of giving astigmatism to the first light beam portion on an anamorphic lens surface.
3).

Further, in the return light beam splitting optical elements 40 and 50 ', the portions for splitting the second and third light beam portions are lens surface portions DL3-1 for separating the respective light beam portions in a direction parallel to the track. DL3-2, DL4
-1, DL4-2 and DL5-1, DL5-2, DL
7-1 and DL7-2 (claim 18).

In the embodiment shown in FIG. 1, the error detection device is an optical pickup device that performs at least one of recording, reproducing, and erasing of information on an optical information recording medium that causes an interference pattern in a returning light beam. A first light beam portion in which a return light beam directed to a return light detection unit is incident, and a density of an interference pattern in a zero-order light of the return light beam does not change, based on the light beam; Return beam splitting optical element 10 for optically splitting into second and third light beam portions where the density of the interference pattern changes reciprocally, and return beam splitting optical element 1
A focusing error signal is generated using the light receiving means 12 having a plurality of light receiving portions PD1 to PD4 for receiving each light beam divided by 0, and the photoelectric conversion outputs of the light receiving portions PD1 and PD2 for receiving the first light beam portion. And a tracking error signal generating unit 14 that generates a tracking error signal using the photoelectric conversion output of the light receiving units PD3 and PD4 that receive the second and third light flux portions. 15).

The embodiment shown in FIG. 2 uses a return beam splitting optical element 20 instead of the return beam splitting optical element 10 in the embodiment shown in FIG. The error detection device according to the embodiment shown in FIGS. 1 and 2 uses the “second light beam splitting optical elements 10 and 20
And the portion that divides the third light beam portion has the same positive power lens action ”(Claim 11).
2 for receiving the second and third light flux portions as light receiving means
PD3, PD4 or PD3 ', PD4'
The tracking error signal generation means generates a tracking error signal of the push-pull method by using the photoelectric conversion outputs of the two light receiving units (claim 16).

The error detecting device according to the embodiment shown in FIGS. 3 and 4 uses the return light beam splitting optical element according to the above-mentioned claim 11, and the second and third light receiving means.
The light receiving surfaces G1, G2, H1, H2 are respectively separated into two portions in the direction parallel to the track.
Or PD3-1, PD3-2, PD4-1, PD4
A tracking error signal of the phase difference detection method is generated by the tracking error signal generation means using the photoelectric conversion outputs of the four light receiving units that receive the second and third light flux portions (the tracking error signal is generated by the tracking error signal generation means). Claim 17) is possible.

In the error detecting device according to the embodiment shown in FIGS. 1 to 4, the return light beam splitting optical element has two lens surfaces in which a portion for splitting the first light beam portion is arranged in a direction parallel to the track. Part DL1, DL2 or DL1 ',
DL2 ', which separates the first light flux portion into two focused light fluxes having different focusing distances from each other, wherein the positive powers of these lens surface portions are different from each other. The portions PD1 and PD2 that receive the respective focused light beams of the first light beam portion separated into two focused light beams having different light distances are divided into three in the track parallel direction.
A focusing error signal of a double beam size method is generated by a focusing error signal generating unit using a photoelectric conversion output of each of the three divided light receiving units by using a divided light receiving unit.

The error detecting device of the embodiment shown in FIGS. 5, 6 and 7 has a structure in which the returning light beam splitting optical element is such that “the first light beam splitting portion is an anamorphic lens surface DL6, The first light beam portion has a lens function of providing astigmatism (Claim 13), and as the light receiving means, the portion for receiving the first light beam portion provided with astigmatism is provided in the track direction. The light-receiving surface is divided into four by a dividing line that is at 45 degrees to each other and is orthogonal to each other.
The focusing error signal of the astigmatism method is generated by the focusing error signal generating unit using the photoelectric conversion output of the four-divided light receiving unit PD6.
(Claim 19).

Therefore, according to each of the embodiments described with reference to FIGS. 1 to 7, one of information recording / reproducing / erasing is performed on an optical information recording medium which causes an interference pattern in a return light beam.
In the optical pickup device performing the above, based on the return light flux, a method for detecting a focusing error and a tracking error, the return light flux toward the return light detection unit,
Return beam splitting optical element 10, 20, 40, 50, 50 '
And the first and second light flux portions where the density of the interference pattern in the zero-order light of the return light beam does not change and the density of the interference pattern changes reciprocally by the return light beam splitting optical element. An error detection method (claim 1) for optically dividing the light into a first light beam portion, detecting a focusing error using the first light beam portion, and detecting a tracking error using the second and third light beam portions. .

In the embodiments shown in FIGS. 1, 2 and 5, the second and third light flux portions are separated from each other by the light receiving portions P.
An error detection method for detecting a tracking error by a push-pull method based on a difference in the amount of light received by each of the light receiving units is performed.

In the embodiments shown in FIGS. 3, 4, 6, and 7, the light receiving portions PD3 ', PD4', and PD3 'each of which divides the second and third light flux portions into two in the track orthogonal direction.
-1, PD3-2, PD4-1, PD4-2, etc., an error detection method (claim 3) for detecting a tracking error by a phase difference detection method is implemented.

In the embodiment shown in FIGS. 1 to 4, the return light beam splitting optical elements 10, 20, and 40 separate the first light beam portion into two focused light beams having different focusing distances from each other. An error detection method (claim 5) for detecting a focusing error by a double beam size method using a light beam is performed.

In the embodiments shown in FIGS. 5 to 7, astigmatism is generated in the first light beam portion by the return light beam splitting optical elements 50 and 50 ', and a focusing error is detected by the astigmatism method. An error detection method (claim 6) is performed.

By the way, the second and third light flux portions in the return light beam are “light flux portions where the density of the interference pattern, that is, the light intensity changes reciprocally”. Thus, the second,
In the third light beam portion, the brightness changes reciprocally when the light spot is deviated from the track. Therefore, in order to generate the tracking error signal, the light receiving means needs the second and third light beam portions. It is not always necessary to detect the total amount of light.

From this point of view, of the return light beam, the portion that divides the second and third light beam portions does not necessarily need to have a lens function. The return light beam splitting optical element 10A in the embodiment shown in FIG. 8 is an example of such a case. This return beam splitting optical element 10A is
In addition, the portion that divides the third light beam portion is configured to have "no lens action" (claim 10), so that the return light beam simply passes through this portion. In the light receiving means, light receiving sections PD3A and PD4 for receiving the second and third light flux portions
A has a light receiving area smaller than the light beam cross section (detection pattern) of the second and third light beam portions so that a change in density in the interference pattern can be detected.

In the embodiment shown in FIG. 9, the return light beam splitting optical element 10B splits the lens surface portions DL1 and DL2 for splitting the first light beam portion from the return light beam, and splits the second and third light beam portions. The lens surface portions DL3 and DL4 are formed separately on the front and back of the transparent parallel plate.

In the embodiments shown in FIGS. 8 and 9, the second and third light flux portions are respectively returned to the return light beam splitting optical element 10A.
Alternatively, an error detection method of dividing the beam into two in the direction perpendicular to the track by 10B, individually receiving the light beams by separate light receiving units PD3A and PD4A, performing a predetermined calculation on the output of each light receiving unit, and detecting a tracking error ( Claim 4) can be implemented.

When the lens surfaces of the return light beam splitting optical element are formed on the front and back surfaces, the lens surfaces formed on each surface are, for example, cylindrical surfaces, and the “anamorphic lens action” is provided by the front and back lens surfaces. It can be realized.

By using the return light beam splitting optical element 10 and the light receiving means 12 in the error detection device of the embodiment of FIG. 1 as, for example, the return light detection unit 8 in FIG. An optical pickup device for performing at least one of recording, reproducing, and erasing of information on an optical information recording medium 9 for generating a pattern, wherein the device detects a focusing error and a tracking error based on a return light beam. An optical pickup device using the error detection device according to the fifteenth aspect can be implemented. Similarly, by using the embodiments of FIGS. 1 to 9, an optical pickup device (claim 23) using the error detection device according to any one of claims 16 to 19 can be implemented.

FIG. 10 is a diagram for explaining an embodiment of the error detecting apparatus according to the twentieth aspect. In this error detecting device, the part that divides the first light beam part is arranged in a direction parallel to the track.
A return beam splitting optical element that includes two lens surface portions, separates the first light beam portion into two focused light beams having different focusing distances from each other, and the positive power of each lens surface portion is different.

As such a return beam splitting optical element,
1, 2 and 3, return light beam splitting optical elements 10, 2
Although 0 and 40 are shown, FIG. 10 assumes the use of the return beam splitting optical element 10 shown in FIG.

As shown in FIG. 10 (a), the light receiving means receives the respective focused light fluxes of the first light flux portion divided into two focused light fluxes having different focusing distances from each other. A focusing error is generated by using the six-divided light receiving unit PD1 ′ (which outputs photoelectric conversion outputs: a1 to c2) and PD2 ′ (which outputs photoelectric conversion outputs: d1 to f2) which are divided and divided into two in the track orthogonal direction. The signal generating means generates the focusing error signal of the double beam size method using the photoelectric conversion outputs of the six-divided light receiving units PD1 'and PD2', and uses the photoelectric conversion output of one of the six-divided light receiving units to track offset. Generate a signal.

In FIG. 10A, reference numerals PD3 and PD4
Is a light receiving section for receiving the second and third light flux portions split from the return light flux (the same as those shown in FIG. 1)
The light receiving units PF1 ′ and PD2 ′ are located on the same plane, and these light receiving units constitute light receiving means.

When the light spot is focused on the recording surface and positioned on the track, the "detection pattern" formed on the light receiving means is as shown in FIG. 1 (b). When the objective lens has not been shifted in the “direction perpendicular to the track (the left-right direction in FIG. 10)” by the tracking drive, the return light beam incident on the return light beam splitting optical element is “shifted” in FIG. As shown as “no return beam”, the center of the beam is the lens surface portion DL1 to D1 of the return beam splitting optical element.
It matches the center of L4.

When the objective lens shifts in the “direction perpendicular to the track” by the tracking drive, the return light beam incident on the return light beam splitting optical element becomes a light beam as shown as “shifted return light beam” in FIG. 10B. The center is shifted from the center of the lens surface portions DL1 to DL4. At this time, the “detection pattern” formed on the light receiving means is as shown in FIG.
(a).

In this state, the aforementioned tracking error signal: TE = gh has a tendency to “decrease the sensitivity”. Such “weakness of sensitivity” is due to “track offset” accompanying the shift of the objective lens. To perform good tracking control, it is better to correct the weakness of sensitivity due to track offset.

For example, the outputs of the light receiving unit PD1 ': a1 to c
2, the signals: A = a1 + b1 + c1, B = a2 + b2 + c2 are generated, and the difference: AB is generated. The signal: AB is proportional to the "track offset amount". Considering TE = gh + K (A−B) as a tracking error signal: TE using a coefficient: K, this signal has a track offset amount:
When AB is small, it matches the above-mentioned tracking error signal: gh.

Therefore, in a situation where a track offset actually occurs, a tracking error signal: TE = g
By setting the coefficient: K so that −h + K (AB) is optimized, good tracking control can be performed regardless of the presence or absence of a track offset.

That is, when the objective lens is shifted in the direction perpendicular to the track by the tracking drive,
The track offset amount signal: A indicates the “track offset amount with respect to the return light beam splitting optical element when the return light beam captured by the objective lens enters the return light beam splitting optical element”.
-B, and corrected by an electrical coefficient: K which has been set experimentally in advance, and a correction value: K (A
By adding -B), a tracking error signal taking into account the track offset amount is obtained.

The track offset amount is the above AB
Not limited to, a1-a2, b1-b2, d1-d2, e1
-E2 etc. can also be used. That is, the second and third light flux portions of the return light beam are shifted by the tracking drive, and the track offset amount is detected based on the difference between the portions entering the lens surface portions DL1 and DL2 and the opposite portions.

In the above example, the tracking error signal itself was corrected by using the track offset amount signal: AB. However, the signal: AB was replaced by “the seek drive servo signal for driving the entire optical pickup device. The optical pickup device may be servo-driven so that the offset does not affect the objective lens.

As shown in FIG. 10A, when there is a track offset, the amount of light incident on the light receiving units PD1 'and PD2' changes, so that the sensitivity of the focusing error signal also becomes weak due to the influence of the track offset.

To avoid this problem, as the focusing error signal: FE, for example, FE = C {(a1 + c1 + e2)-(b1 + d2 + f2)} +
D {(a2 + c2 + e1)-(b2 + d1 + f1)} may be used. Here, C and D are comparators 10
1 and 102.

The comparators 101 and 102 compare the magnitude relationship between the photoelectric conversion outputs: e1 and e2, and “C = 1 and D = 0 when e1 ≧ e2”, and “C = 0 and D = when e1 <e2”.
1 "is output.

FIG. 11 shows a return light beam splitting optical element.
FIG. 3 is a diagram for explaining “case in which the influence of track offset is reduced” when the return beam splitting optical element 20 shown in FIG. 2 is used.

FIG. 11 (a) shows the return light beam splitting optical element 20.
(B) indicates a state in which the return light beam is shifted.
Shows the state of the “detection pattern” in the light receiving means in the state of FIG. The light receiving sections PD1 'and PD2' of the light receiving means are the same as those in FIG.
Are the same as in FIG.

Also in this case, the tracking error signal TE = gh + K (AB) and the focusing error signal FE = FE = C {(a1 + c1 + e2)-(b1 + d2 +), just like the embodiment of FIG.
f2)} + D {(a2 + c2 + e1)-(b2 + d1 + f1)}, the effect of the track offset can be reduced to perform the focusing control and the tracking control.

In the embodiment shown in FIGS. 10 and 11, each of the light receiving portions PD1 'for receiving the first light beam portion divided by the return light beam splitting optical element and separated into two converged light beams,
The PD2 'is divided into two in the direction parallel to the track, and an error detection method (claim 7) for detecting the track offset amount: AB based on the output from one of the light receiving sections PD1' is performed.

FIG. 12 is a diagram for explaining an embodiment of the error detecting device according to the twenty-first aspect. In this error detection device, the “partial portion that divides the first light beam portion is an anamorphic lens surface, and has a lens function of giving astigmatism to the first light beam portion. An element is used.

Such return light beam splitting optical elements are shown as return light beam splitting optical elements 50 and 50 'in FIGS. 5 and 7, but in the embodiment shown in FIG. Is assumed. Fig. 5
It is the same as that of (b).

As shown in FIG. 12, the light receiving means is configured such that “a portion for receiving the first light beam portion given astigmatism is
A four-divided light receiving unit PD6 in which the light receiving surface is divided into four by a dividing line that is at 45 degrees to the track direction and is orthogonal to each other.

The focusing error signal generating means generates a focusing error signal of the astigmatism method and a track offset amount signal using the photoelectric conversion output of the four-divided light receiving unit PD6.

In such a configuration of the return light detecting section, the track offset is “tracking error signal
It acts to weaken the "sensitivity of the focusing error signal". To reduce the influence of the track offset, the following may be performed.

That is, the output of the light receiving unit PD6: difference between m and n:
mn is used as a "track offset amount signal" to detect the track offset amount.

A tracking error signal: TE is a coefficient:
Using K ′, TE = ef + K ′ (m−n), and a coefficient: K ′ is experimentally set so that this signal is optimized. By doing so, good tracking control can be performed regardless of the presence or absence of a track offset.

Also in this case, the track offset amount signal:
The tracking error signal itself was corrected using mn, but the above signal: mn was defined as "a part of the seek drive servo signal for driving the entire optical pickup device", and the light was controlled so that the offset of the objective lens did not affect the signal. The pickup device may be servo-driven.

To reduce the influence of the track offset in the focusing control, for example, FE = (k + j) −2 (E × c + F × d) may be used as the focusing error signal FE. The outputs m and n are input to two comparators in the same manner as the outputs e1 and e2 in the case of FIG. 10, and the outputs E and F of these two comparators. For example, when m ≧ n, E = 1, F = 0, E = when m <n
0, F = 1.

In this way, even if m and n change from the original output due to the track offset, twice the larger amount of received light is replaced by the value of m + n. There is no effect.

In the embodiment shown in FIG. 12, the four-division light receiving means PD6 for receiving the first light beam portion given astigmatism is used.
An error detection method (claim 8) for detecting the track offset amount based on the difference between the outputs of the two light receiving surfaces in the direction orthogonal to the track: mn. The tracking error signal itself may be corrected using the detected track offset amount, or the optical pickup device may be used so that the offset of the objective lens does not affect the seek drive servo signal for driving the entire optical pickup device. May be servo-driven.

The light receiving portions PD3A and PD3A for receiving the second and third light beams divided by the return light beam splitting optical elements 10A and 10B in the embodiments of FIGS. 8 and 9 described above.
If the light receiving area is smaller than the detection patterns of the second and third light beam portions as in D4A, even if the return light beam is shifted with respect to the return light beam splitting optical element due to the tracking drive, the light receiving portions PD3A and PD4A are not Since it is included in the detection pattern, the tracking control / focusing control can be executed with the normal tracking error signal and focusing error signal without being affected by the track offset.

Further, by using the embodiment shown in FIGS. 10 to 12, an error detecting device as claimed in claim 2 is provided.
An optical pickup device using the optical pickup device according to the present invention can be implemented.

FIG. 14 is a diagram showing an embodiment of the optical information recording and processing apparatus of the present invention.

The optical information processing apparatus is an optical information processing apparatus that performs at least one of recording, reproducing, and erasing of information on a disk-shaped optical information recording medium that causes an interference pattern in a return light beam. Holder 61 on which medium 60 is set
And a motor M as a “driving unit” that rotationally drives the optical information recording medium 60 set in the holding section 61, and performs one of recording, reproduction, and erasing on the set optical information recording medium 60.
It has an optical pickup device 62 for performing the above, and a displacement driving means 63 for driving the optical pickup device 62 to be displaced in the radial direction of the optical recording medium 60.

As the optical pickup device 62, the device using any one of claims 22 to 24 described in the above embodiments is the same as that of the optical information processing device according to claim 25. is there. The control means 64 in FIG.
Is configured by a microcomputer or the like, and controls each unit of the optical information processing apparatus.

The return light beam splitting optical elements 10, 20, 40, 50, 50 ', etc. shown in the above embodiments may be formed by plastic molding or special surface shape generation described in JP-A-9-146259. It can be manufactured by a known appropriate method such as a method, and the size can be appropriately set according to the light beam diameter of the returning light beam and the optical layout of the optical pickup device.

[0148]

As described above, according to the present invention, a novel error detecting method, an error detecting device, a returning light beam splitting optical element, an optical pickup device, and an optical information processing device can be realized.

The return light beam splitting optical element of the present invention can split the return light beam into a light beam portion necessary for tracking error detection and focusing error detection, and can give the split light beam a necessary light beam form.

Therefore, the error detection method and apparatus using the return light beam splitting optical element can reduce the size of the return light detection section and promote the miniaturization of the optical pickup device and optical information processing device of the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of an error detection device.

FIG. 2 is a diagram for explaining another embodiment of the error detection device.

FIG. 3 is a diagram for explaining another embodiment of the error detection device.

FIG. 4 is a diagram for explaining another embodiment of the error detection device.

FIG. 5 is a diagram for explaining another embodiment of the error detection device.

FIG. 6 is a diagram for explaining another embodiment of the error detection device.

FIG. 7 is a diagram for explaining another embodiment of the error detection device.

FIG. 8 is a diagram for explaining another embodiment of the error detection device.

FIG. 9 is a diagram for explaining another embodiment of the error detection device.

FIG. 10 is a diagram for explaining another embodiment of the error detection device.

FIG. 11 is a diagram for explaining another embodiment of the error detection device.

FIG. 12 is a diagram for explaining another embodiment of the error detection device.

FIG. 13 is a diagram illustrating an optical pickup device.

FIG. 14 is a diagram illustrating an optical information processing apparatus.

[Explanation of symbols]

 10 Return beam splitting optical element 12 Light receiving means FX Return beam

Claims (25)

[Claims] An optical pickup device for performing at least one of recording, reproducing, and erasing of information on an optical information recording medium that causes an interference pattern in a return light beam, based on the return light beam,
A method for detecting a focusing error and a tracking error, comprising: causing a return light beam directed to a return light detection unit to enter a return light beam splitting optical element, and using the return light beam splitting optical element, an interference pattern of zero-order light of the return light beam. It is optically divided into a first light beam portion where the density does not change and second and third light beam portions where the density of the interference pattern changes reciprocally, and a focusing error is reduced using the first light beam portion. Detecting a tracking error using the second and third light flux portions. 2. The error detection method according to claim 1, wherein the second and third light flux portions are received by light receiving portions that are separate from each other, and a tracking error is detected by a push-pull method based on a difference in the amount of light received by each light receiving portion. Error detection method. 3. The error detecting method according to claim 1, wherein each of the second and third light beams is received by a light receiving section divided into two in a direction parallel to the track, and a tracking error is detected by a phase difference detection method. An error detection method characterized by detecting. 4. The error detecting method according to claim 1, wherein each of the second and third light flux portions is separated into two in a direction parallel to the track by a return light beam splitting optical element, and each of the separated light fluxes is separated. An error detection method characterized in that light is individually received by separate light receiving units, a predetermined calculation is performed on the output of each light receiving unit, and a tracking error is detected. 5. The error detecting method according to claim 1, wherein the first light beam portion is separated into two focused light beams having different focusing distances by a return light beam splitting optical element.
An error detection method characterized by detecting a focusing error by a double beam size method using two focused light beams. 6. The error detection method according to claim 1, wherein astigmatism is generated in the first light beam portion by the return light beam splitting optical element, and a focusing error is detected by the astigmatism method. Error detection method. 7. The error detecting method according to claim 5, wherein each of the light receiving portions for receiving the two converged light beams is divided into two in a direction orthogonal to the track, and a track offset amount is determined based on an output from one of the light receiving portions. An error detection method comprising: detecting an error. 8. The error detection method according to claim 6, wherein a difference between outputs of two light receiving surfaces in a direction orthogonal to a track of a four-division light receiving unit that receives the first light beam portion provided with astigmatism. An error detection method, wherein a track offset amount is detected based on the following. 9. A return beam splitting optical element used for implementing the error detection method according to claim 1, wherein the return beam is formed integrally with a transparent material, and the return beam does not change in the density of the interference pattern in the zero-order light. It is configured to optically divide into a first light beam portion and second and third light beam portions in which the density of the interference pattern changes reciprocally, and at least a portion that divides the first light beam portion is positive. A returning light beam splitting optical element having a lens function of the following power: 10. The return light beam splitting optical element according to claim 9, wherein a portion for splitting the second and third light beam portions has no lens function. 11. The return light beam splitting optical element according to claim 9, wherein the portions for splitting the second and third light beam portions have the same positive power lens action. element. 12. The return light beam splitting optical element according to claim 9, wherein the portion for splitting the first light beam portion comprises two lens surface portions arranged in a direction parallel to the track. A returning light beam splitting optical element, wherein the first light beam portion has different positive powers and is split into two focused light beams having different focusing distances. 13. The return light beam splitting optical element according to claim 9, wherein the portion for splitting the first light beam portion is an anamorphic lens surface, and a lens function for giving astigmatism to the first light beam portion. A return light beam splitting optical element, comprising: 14. The return light beam splitting optical element according to claim 9, wherein the portions for splitting the second and third light beam portions are respectively:
A returning light beam splitting optical element, wherein each light beam portion is divided into two lens surface portions for separating the light beam portions in a direction parallel to a track. 15. An optical pickup device for performing at least one of information recording, reproduction, and erasure on an optical information recording medium that causes an interference pattern in a return light beam, wherein a focusing error and a tracking error are detected based on the return light beam. An apparatus, which receives a return light beam directed to a return light detection unit, and converts the return light beam into a first light beam portion in which the density of the interference pattern in the zero-order light of the return light beam does not change, and the density of the interference pattern is opposite. Return light beam splitting optical element for optically splitting the light beam into second and third light beam portions that change in a continuous manner, and light receiving means having a plurality of light receiving sections for receiving each light beam split by the return light beam splitting optical element Focusing error signal generating means for generating a focusing error signal using a photoelectric conversion output of a light receiving unit for receiving the first light beam portion The error detecting apparatus characterized by comprising a tracking error signal generating means for generating a tracking error signal using a photoelectric conversion output of the light receiving portion for receiving the second and third light beam portions of. 16. An error detecting device according to claim 15, wherein the return light beam splitting optical element is the one described in claim 10 or 11, and the light receiving means receives the second and third light beam portions. An error detection device comprising: a light receiving unit having a plurality of light receiving units; and a tracking error signal generating means for generating a tracking error signal of a push-pull method by using photoelectric conversion outputs of the two light receiving units. 17. An error detecting apparatus according to claim 15, wherein the return light beam splitting optical element is the one described in claim 10 or 11 or 14, and the light receiving means receives the second and third light beam portions. Each of the light receiving portions has a light receiving portion separated into two portions in a direction parallel to the track, and the tracking error signal generating means performs photoelectric conversion of the four light receiving portions receiving the second and third light flux portions. An error detecting device for generating a tracking error signal of a phase difference detection method using an output. 18. An error detecting apparatus according to claim 15, wherein the return light beam splitting optical element is the one described in claim 12, and the light receiving means is a second light beam split into two focused light beams having different focusing distances. The portion of each light beam portion that receives each converged light beam is divided into three portions in a direction parallel to the track.
An error detecting apparatus, wherein a splitting light receiving unit is used, and a focusing error signal generating unit generates a focusing error signal of a double beam size method using the photoelectric conversion output of each of the three divided light receiving units. 19. An error detection device according to claim 15, wherein the return light beam splitting optical element is the one described in claim 13, and the light receiving means receives a first light beam portion provided with astigmatism. The light receiving surface is divided into four parts by dividing lines that are at 45 degrees to the track direction and are orthogonal to each other.
An error detecting apparatus, wherein a focusing error signal is generated by an astigmatism method using a photoelectric conversion output of the four-divided light receiving unit by a focusing error signal generating unit using a divided light receiving unit. 20. An error detection device according to claim 15, wherein the return light beam splitting optical element is the one described in claim 12, and the light receiving means is divided into two converged light beams having different focusing distances from each other. A portion of each light beam portion that receives each converged light beam is divided into three in a direction parallel to the track,
A focusing error signal of a double beam size method is generated by using a photoelectric conversion output of each of the six divided light receiving units by a focusing error signal generating unit using a six-divided light receiving unit divided into two in a direction orthogonal to the track. An error detection device that generates the track offset amount signal using the photoelectric conversion output of one of the six-divided light receiving units. 21. The error detecting device according to claim 15, wherein the return light beam splitting optical element is the one described in claim 13, and the light receiving means receives a first light beam portion provided with astigmatism. The light receiving surface is divided into four parts by dividing lines that are at 45 degrees to the track direction and are orthogonal to each other.
A focusing error signal generating means for generating a focusing error signal of an astigmatism method and a track offset amount signal by using a photoelectric conversion output of the four-division light receiving unit by using a divided light receiving unit; An error detection device characterized by the above-mentioned. 22. An optical pickup device for performing at least one of recording, reproducing, and erasing of information on an optical information recording medium that causes an interference pattern in a return light beam, wherein a focusing error and a tracking error are detected based on the return light beam. An optical pickup device using the error detection device according to claim 15 as a device for detecting. 23. The optical pickup device according to claim 22, wherein the error detection device is any one of claims 16 to 19. 24. The optical pickup device according to claim 22, wherein the error detection device according to claim 20 or 21 is used. 25. Recording / reproduction / reproduction of information on / from a disc-shaped optical information recording medium which causes an interference pattern in a return light beam.
An optical information processing apparatus for performing at least one of erasing, a holding unit on which the optical information recording medium is set, a driving unit for rotating and driving the optical information recording medium set on the holding unit, Recording / reproducing /
25. An optical pickup device for performing at least one of erasing, and a displacement driving means for driving the optical pickup device to be displaced in a radial direction of the optical information recording medium. An optical information processing apparatus using the device described in (1).