JPH02214037A - Optical information processor - Google Patents

Abstract

PURPOSE:To attain the miniaturization, light weight, and low cost of a device by reducing the area of a light receiving element by setting the width of a beam of light on a light emitting element side limited by an aperture member equal or narrower in a first direction and equal or wider in a second direction for the width of the light receiving element. CONSTITUTION:A LED 102 provided with the light emitting element 4 and a collimator part 101 is fixed on a side opposite to that of an objective lens 3 centering a rotary shaft 2, and almost parallel beams of light 9 are emitted from the LED. The beams of light 9 are limited by a rectangular aperture slit 103 extending in a tangential direction, and irradiates the light receiving element 104 extending in a tracking direction. By employing such a constitution, the element 104 can be miniaturized. In figure (a) where the beams of light 9 are positioned at the intermediate part of the light receiving elements 104a and 104b, the differential signal of them goes to (a), and in figures (b)-(c), a signal goes up to lens position output, then, is flattened, and after that, it is reduced in figures to (e), then, it goes to 0 after figure (e). A reverse result is obtained when the beams of light 9 move in a reverse direction, and the differential signal goes to a negative level. And the range of linear change can be used actually. An activity range can effectively be taken widely in such a constitution.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention comprises an objective lens actuator having means for detecting the position of an objective lens that converges and irradiates a light beam onto an information recording medium. It is related to the device.

[Conventional technology]

Generally DRAW (Dlr@ct Read After
In the original disk device of the r Write ) type or the rewritable type, a spiral tracking guide groove is previously provided on the disk. The pitch of the guide groove is 1μ
Since it is very small, on the order of m, diffraction occurs when a light spot is irradiated, and the diffracted light is scattered in a direction perpendicular to the track. The Butsugur type tracking device detects changes in brightness in the pattern of the 0th order and ±1st order diffracted light on the tracking detector.

It is extracted as a king error signal and used for tracking servo.

By the way, in optical disk devices that perform tracking surveillance by moving an objective lens that condenses a minute spot on a predetermined track relative to a detector for tracking, if there is a large eccentricity on the disk, it will cause problems on the detector. The center of the track and track moves, causing an offset in the tracking error signal, making it difficult to accurately track and track. Regarding this, Figure 4+11, (ii)
Let's briefly explain using.

FIG. 4(1) shows a part of the optical disk device necessary for performing the tracking search. Semiconductor lede (
A light beam 10 from a disk (not shown) is focused by an objective lens (e3) onto a predetermined track of a disk 8 having a tracking guide groove (not shown). The objective lens 3 is moved by an actuator (not shown) according to the eccentricity of the disk (9)
Track the truck in the racking direction.

When the eccentricity of the disk 8 is extremely small, the original axis of the objective lens and the center of the light beam from the radar almost coincide, and there is an asymmetry in the ±1st-order diffraction source that corresponds to the positional deviation between the track and the spot. The diffracted light flux enters the objective lens 3 again./% -7 The light flux reflected by the mirror 15 reaches the two-split detector 14as14b. ) on the 7'' itector are located symmetrically with respect to the dividing line as shown in Figure 4+11(b), and the j5 tracking error is due to the asymmetry of the ±1st-order diffracted light on 14m and 14b. This will generate a signal.

If the disk 8 is eccentric by D, the objective lens 3 will track it, so the center of the light beam from the radar will be incident with a deviation from the center of the objective lens by D. As a result, the spot on the detector will also be incident asymmetrically with respect to the dividing line, as shown in Figure 4 (b) or (c).

The differential output of 14a, 14b produces an offset δ. If you perform a search based on the tracking error signal that caused the offset δ, will the original beam be correctly aligned? 11
The inability to retain information makes it difficult to record and reproduce accurate information.

Still another conventional example is shown in FIG. 4+11, trr).

In FIG. 4, the actuator that drives the objective lens 3 in the front and rear directions is, for example, an objective lens holding member 1t.
-Rotation center 2'j&: It is rotated around the center. 16 is a counterweight of the objective lens 3. In addition, in the direction of the 7 orcus, the objective lens holding member 1 is rotated at the center of rotation 2.
In the type shown in FIG. 5 (1), the light beam from the light emitting element 4 such as an IJD fixed outside the actuator is shaped by passing through the entire aperture 5, and then the light beam is divided into two parts fixed to the objective lens holding member 1. 6 is a diagram showing projection of a spot 9 onto a detector 6. FIG. By differentially detecting the output of the two-split detector using the differential amplifier 12, the position of the objective lens 3 can be known. In addition, in FIG. 5 (11), the lens is fixed to the lens holding member 1 for safety! jy) 5't'' to project the luminous flux from the light emitting element 4 fixed outside the actuator to the two-split detector 6 as a spot 9.The output of the two-split detector 6 is transmitted to the differential amplifier 12. By detecting it, the entire tracking position of the objective lens 3 can be known in the same way.

In the case of (1), these conventional devices have a two-part sensor at
In the case of -ti), since the slit 5 is attached to the objective lens holding member 1 of the actuator, there is a problem that the weight of the actuator movable part increases. Further, since the two-part sensor 6, the slot, and the slot 5 are all attached to the end of the sensor 1, there is a problem in that a large moment of inertia is generated, making it difficult to maintain dynamic balance.

A light emitting element 4 and a light receiving element 6 are provided outside the agitator unit.
The ninth problem with arranging the head is that the entire original head becomes spatially large.

Furthermore, in humans, the light-receiving element moves on the circumference, and in B, when all the light-emitting elements, such as LEDs, are used, the emitted light beam generally diverges, so the IJ of the objective lens position signal
This has the problem of deteriorating the quality.

In order to overcome the drawbacks of these two examples, we focused on the fact that the aforementioned rotary actuator requires a counterweight 16 at a position symmetrical to the objective lens 3 around the rotation axis 2 in order to ensure its dynamic performance. However, there is a conventional example in which an element (for example, a light emitting element, a slit, a light receiving element, etc.) necessary for rounding the objective lens position detection is used instead of the counterweight or as a part of the counterweight.

In FIG. 2 (1), 1 is an objective lens holding member.

2 is the center of rotation. 3 is the objective lens. 4 is a light emitting element. A collimator lens 17 converts the light beam 9 from the light emitting element 4 into a parallel light beam. 5 is a slit. 6 is a two-part light receiving element. 7 is the actuator mounting base.

8Fi optical disk. 9 digits 4 to 5'ft: The luminous flux that reaches 6 through 9 ft. 10 is a luminous flux from a semiconductor radar (not shown). 11 is a former beam spot. 12 is a differential amplifier. 13 is a summing amplifier. FIG. 2 (1) is a plan view of the conventional example. Figure 2 is a sectional view taken along line x-x' in Figure 2 (11).

FIG. 2(iii) is an electrical circuit diagram for obtaining an objective lens position signal.

In FIG. 5, on the side of the counterway 16 indicated by orj, there is a collimator lens 17 which converts the light beam 9 from the light emitting elements 4, 4 into a parallel light beam in FIG. The light flux from the arranged detector 4 is shaped into an appropriate shape by 5 and then reaches a two-split detector 6. The two-split detector 6 has a dividing line perpendicular to the tracking direction. When the center of the objective lens 3 and the optical axis of the light beam 10 from the radar coincide (in the case of eccentricity O), 6
If the output from each detector a and 6b is adjusted to be equal, when the objective lens is decentered, the spot 9 on 6 will move and a specific output will be generated in proportion to the objective lens position as shown in Figure 3. do.

[Problem to be solved by the invention]

However, in the conventional example as described above, the light beam 9 limited by the slots 5 (rectangular in this example) has a width in the tracking direction and a width in the tangential direction of the light receiving element 6, as shown in FIG. 2 (611). Both the width and the bottom are narrower,
In addition, even if the objective lens holding member 1 rotates during tracking operation and the light beam 9 moves in the tracking direction, the light beam 9 always enters the light receiving element 6 and is designed so that it does not come out. . For this reason, the light i of the light beam 9 is sufficiently secured, and the movement 1tt of the light beam 9 plus the width on the dividing plate and the width in each of the front, king, and tangential directions, which takes into account assembly errors, are received. This is necessary for the element 6, and there is a problem in that the enlargement of the light receiving element 6 results in an increase in the size of the device and a reduction in cost.

Furthermore, in this example, the light-receiving element 6 is not enclosed in a protective cage or the like, so it is vulnerable to changes in the environment.
Since the light receiving element 6 itself is large, a problem arises in that the package also becomes larger accordingly. Furthermore, the +7- wire (not shown) from the light receiving element 6 to the outside is complicated because it has to be fixed to a base (not shown) for all the light receiving elements, and then connected to the IJ- wire using a wire or the like. , making it difficult to reduce costs.

〔the purpose〕

The present invention was developed in view of the problems of the prior art described above, and its purpose is to appropriately adjust the luminous flux on the light emitting element side that is limited by the aperture member.

Provides a single-source information processing device that can reduce the area of the light-receiving element, can be made smaller even if it is made into a molded motherboard, can be easily wired, can be made lighter, and can reduce costs. It's about doing.

[Means to solve the problem]

According to the present invention, the above object includes: an actuator that drives a movable part that holds an objective lens that converges and irradiates a light beam onto an information recording medium; a light emitting element or a light receiving element fixed to the movable part; A light-receiving element is fixed to a fixed part in the device when the light-emitting element is provided in the movable part, and a light-emitting element is fixed to the fixed part in the device when the light-receiving element is provided in the movable part. Don't do it.

Detecting the luminous flux emitted by the light emitting element with the light receiving element,
In a source information processing device that detects the entire position of the objective lens in the direction to be detected; out of the light flux emitted by the light emitting element, the light flux in the first direction to be detected is the same as that of the first direction of the light receiving element. and the luminous flux width of the light emitting element in a second direction perpendicular to the direction in which the detection is based is equal to the width of the light receiving element in the second direction. This is achieved by a former information processing device, characterized in that it is or is widely used.

〔Example〕

Hereinafter, embodiments of the present invention will be described specifically and in detail based on the drawings.

Note that the same numbers are given to the parts used in the conventional example and also used in the present invention, and the description thereof will be omitted.

FIG. 1 (1) is a plan view of the present invention, (11) is an x-x' sectional view inside, and (iii) is an electric circuit diagram for obtaining an objective lens position signal.

In the figure, the rotation axis 2'! ! - objective lens 3 as the center
9L with a light emitting element 4 and a collimator section 101 on the opposite side.
A gD 102 is fixed, and a substantially parallel light beam 9 is emitted from this LED 102.

Next, as seen in the same figure (iii), this luminous flux 9 is
A rectangular opening slit 103 long in the tangential direction
On the contrary, the light is irradiated onto a rectangular light-receiving element 104 that is elongated in the front and back directions. With this configuration, the second conventional example
As shown in the figure, the drawback that the light receiving element 6 always had to be large due to the light beam 9 limited by the aperture 5 is eliminated, and the light receiving element 104 can be made small.

In this embodiment, the light receiving element 104 is mounted in a molded package 105 made of almost transparent resin.

It is caged and has a structure that is resistant to environmental changes.

! ff1106 is molded and sealed at the same time as the mold package 105, and this electrode is connected to the bonding wire 1.
09 to the upper end of the light receiving element.

Saraniden ff1l O6i, photodetector 104m, 104
It is electrically connected to the backside battery case (not shown) of b with a conductive adhesive or the like.

Furthermore, as shown in FIG. (as shown). In this embodiment, the electrode 106 and the flexible printed circuit board (not shown) are connected by soldering.

Due to the movement of the light beam 9 in the tracking direction, the objective lens 3
The center of and the optical axis of the light beam 1o from the laser coincide with -f. !
By adjusting the output from each light receiving element of i4m and 104b to be equal, when the objective lens moves in the eccentric direction, that is, in the center and king directions, the The light beam 9 on each light receiving element moves, and as shown in the graph of FIG. 3 mentioned above, the specific output αD (V) is proportional to the objective lens position ff1t D (tm).
'! occurs in

Next, Figure 6 (a), (b), (c), (d
How the lens position output changes as the objective lens moves in the tracking direction will be explained with reference to FIGS.

As shown in Fig. 6 (1), the light beam 9 is transmitted to the light receiving elements 104m and 104.
When located between (middle) b, 104m and 104
The differential signal of b is shown in FIG. 7 (al).

FIG. 6 (Up to the position bl, that is, one end (f) of the light beam 9 is 1
Until it was located between 04m and 104b.

The differential signal between 104m and 104b increases to the lens position output B (V) in FIG. 7(b).

Until the position shown in FIG. 6(c), that is, the other end of the luminous flux 9 (gl is 1
04b, the differential signal between 104& and 104b remains constant from bl to (c) in FIG.

Furthermore, the differential signal between 104a and 104b decreases until one end (f) of the light beam 9 is located at the end of 104b, passing through FIG. 6(d) and reaching the position shown in FIG. Figure 7 (d
), (as shown in @l, and the differential signal becomes O from FIG. 7(e) onwards.

When the light beam 9 moves in the tracking direction in the opposite direction to that described above, the opposite result will occur, and the differential signal will become negative.

What is actually used is shown in Fig. 7 (h) - (al -
(b) is the range. The longer this range and the longer the range with good linearity, the better. It is desirable that at least the above conditions are satisfied within the actual operating range of the objective lens. Therefore, the width of the light receiving element in the tangential direction is By making the length shorter than before, there is a great advantage.

The present invention may be modified in addition to the embodiments described above, and the present invention includes such modifications as long as they do not depart from the scope of the claims.

In this embodiment, an objective lens actuator of a type that slides and rotates about the central axis is used. However, the present invention is not limited to this, and also includes a type that is supported by a leaf spring or a wire. However, the objective lens actuator method is not used.

In this embodiment, the light beam from one light emitting element is shaped into a parallel light beam using a collimator, but within the scope of the claims, it is also possible to use diverging light or converging light without using a collimator. or,
Position f of the light emitting element, collimator, aperture member, and light receiving element
Is it? The light-receiving element is placed on the bottle side, and the light-emitting element is placed on the base side.
A collimator and an aperture member may be provided.

The electrodes of the molded package of this embodiment may be used as a 7-lexiple printed circuit board and the light-receiving element may be arranged on the board. It's advantageous.

In addition, as shown in FIG. 8, due to assembly errors or component errors, the light beam may not be aligned with the light receiving element 1 in the tangential direction.
Even if a missing portion occurs on 04a and 104b, the level of the differential signal will decrease, but it can still be used.

In this embodiment, for example, a photodiode divided into two in the tiger and king directions is used as the light receiving element, but the invention is not limited to this.
1-division (one) at least one-dimensional position sensor (PSD: Po@1tionS@n5itive
Def@ctor) etc. may be used, and the light emitting element may also be
It is not limited to ED.

〔Effect of the invention〕

As explained in detail above, among the light fluxes on the light emitting element side after being restricted by the aperture member, the width of the light flux in the tracking direction is set to be equal to or narrower than the width of the light receiving element in the tracking direction, By setting the beam width in the tangential direction to be equal to or wider than the width of the light receiving element in the tangential direction, the area of the light receiving element can be reduced, the cost can be reduced, and the mold/'? ,
Even if it is made into a cage, it is possible to reduce the size, and it is possible to provide an optical information processing device that is easy to wire and lightweight.

[Brief explanation of the drawing]

FIG. 1 (1) is a plan view of an embodiment of the present invention, and FIG. 1 (11) is a cross-sectional view taken along the x-x' line in FIG. 1. FIG. 3 is an electrical circuit diagram for obtaining an objective lens position signal of the invention. Fig. 2 (1) is a plan view of the conventional example, Fig. 2 (11) is a cross-sectional view taken along the line X-X in Fig. 2 (1), and Fig. 2 (llll is the objective lens of the conventional example). FIG. 3 is a graph showing the relationship between the objective lens position and the lens position output. FIG. 4 is an optical diagram of a conventional optical disk device. Zutaku no (al, (b), (a)
is a differential output diagram on the detector in FIG. 4. FIG. 5(1) is a perspective view of a bottle, each showing a conventional example. Figure 6 (at, (b), (cl, (di)
, (al) and FIG. 8 are plan views showing the positional relationship between the light flux and the light receiving element of the present invention. FIG. 7 is a graph showing the relationship between the objective lens position and the lens position output of the present invention. 1 : Objective lens holding member. 2: Rotation shaft, 3: Objective lens, 4: Light emitting element, 104m, 104b: 2-split light receiving element.

Claims (1)

[Claims] (1) an actuator that drives a movable part that holds an objective lens that converges and irradiates a light beam onto an information recording medium;
A light-emitting element or a light-receiving element fixed to the movable part, a light-receiving element fixed to a fixed part in the device when the light-emitting element is provided to the movable part, and a light-receiving element fixed to the fixed part in the apparatus. a light emitting element fixed to a fixed part in the device; detecting the light flux emitted by the light emitting element with the light receiving element;
In an optical information processing device that detects a position of the objective lens in a direction to be detected; of the luminous flux emitted by the light emitting element, a width of the luminous flux in the first direction to be detected is equal to the width of the luminous flux in the first direction of the light receiving element. and the luminous flux width of the light emitting element in a second direction perpendicular to the direction to be detected is equal to or wider than the width of the light receiving element in the second direction. An optical information processing device characterized by: