JPH025227A - Optical information processing device - Google Patents

Abstract

PURPOSE:To reduce the weight of an optical information processor by fixing a collimator lens on a flexible printed board to change the luminous fluxes received from the light emitting and receiving elements into the parallel luminous fluxes. CONSTITUTION:A concentrical or point-containing positioning land pattern part 26 is prepared on a flexible printed board 20. Then a collimator lens 21 is positioned and fixed on the board 20 with a guide of the outer circumference part of the part 26. While a light emitting element 27 is fixed with conduction before the lens 21 is positioned with a guide of only the part 28 or a positioning recessed part 29, as well. Thus it is possible to reduce the size and the weight of various optical elements needed for detection of the position of an objective lens and also to improve the detecting accuracy for the position of the objective lens.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an optical information processing device equipped with an optical system driving device having means for detecting the position of an optical system for irradiating an information recording medium with a light beam. It is related to the device.

[Conventional technology]

Generally, DRAW (Dirsct Read After
In a rewritable type optical disk device or a rewritable type optical disk device, 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. In the Gutshuguru type tracking device, tracking surging is performed by extracting changes in the brightness of the zero-order and ±1st-order diffracted light/mother turns on a tracking detector as a tracking error signal.

By the way, in an optical disk device that performs tracking sensor closing by moving an objective lens that condenses a minute spot on a predetermined track relative to a tracking day shifter, if there is a large eccentricity on the disk, it may cause problems on the detector. The spot center moves, causing an offset in the tracking error signal, making it difficult to perform accurate tracking. This will be briefly explained using FIGS. 4 and 5.

FIG. 4 shows a part of the optical disk device necessary for performing tracking servo. A light beam 40 from a semiconductor radar (not shown) is focused by an objective lens 83 onto a predetermined track of a disk 88 having a tracking guide groove (not shown). The objective lens 83 tracks the track in the tracking direction by an objective lens drive device (not shown) as the disk decenters. disk 88
When the eccentricity of The light enters the objective lens 83. The nine beams are reflected by the no-f mirror 45 and reach two divided detectors 44m and 44b. The spots on the detector are located symmetrically with respect to the dividing line as shown in No. 5N6), and a tracking error signal is generated due to the asymmetry of the ±1st order diffracted light on 448 and 44b.

For example, if the disk 88 has an eccentricity D as shown in FIG. 4, the objective lens 83 will track this, so the center of the light beam from the laser will be incident with a deviation from the center of the objective lens by D. As a result, the spot on the r-itector is also incident asymmetrically with respect to the dividing line, as shown in FIG.

The differential output of 44b produces an offset δ as shown in the graph of the figure. If the offset δ is generated and the search is performed based on the tracking error signal, the light beam spot 41 cannot be correctly kept on the track, making it difficult to accurately record and reproduce information.

A conventional example for solving this problem is shown in FIG. 6(a).

Shown in (b). In FIG. 6, the objective lens driving device that drives the objective lens 83 in the tracking direction rotates the objective lens holding member 81 around a rotation center 82, and the objective lens holding member 81 rotates in the focusing direction.
The explanation will be given assuming that 1 is of a type that slides around a center of rotation 82Ka. In the conventional example shown in FIG. 6-), a light beam from a light emitting element 84 fixed to a base or the like outside the objective lens driving device is shaped through an aperture 85, and then fixed to an objective lens holding member 81 and directed onto a 7t2 split detector 86. It is irradiated as a spot 89. By differentially detecting the output of the two-split detector 86 using the differential amplifier 42.

The position of the objective lens 83 in the tracking direction can be known. Further, in the conventional example shown in FIG. 6(b), a slit 85 fixed to a lens holding member 81 is used to irradiate a light beam from a light emitting element 84 fixed outside the actuator to a t-2 split detector 86 as a spot 89. do. By differentially detecting the output of the two-split detector using the differential amplifier 42, the position of the objective lens 83 in the tracking direction can be similarly determined.

In these conventional devices, the two-split sensor 86 in the case of FIG. 6 (1) and the slit 85 in the case of FIG. There is a problem that the weight of the parts increases. Further, since both the two-split sensor 86 and the slit 85 are attached to the end of the holding member 81, a relatively large moment of inertia is generated, and there is a problem that dynamic balance is difficult to maintain.

Further, there is a problem in that the light emitting element 84 and the light receiving element 86f are rounded and arranged outside the actuator, and the entire optical head becomes spatially large.

Furthermore, in Figures 7(a) and (a), the light-receiving element moves on the circumference, and in Figures 8(a) and (b), when an LED or the like is used as the light-emitting element, As a result, the emitted light beam diverges, and the linearity (accuracy) of the objective lens position signal deteriorates.

In order to ensure the dynamic performance of the above-mentioned rotary type objective lens drive device shown in FIG. With a focus on
Used as a guard for a t-counterweight or as part of a counterweight. As a result, in this conventional example, (1) the deterioration in actuator performance due to the weight of the element attached to the objective lens holder phase required for detecting the objective lens position is minimized; (2) The dynamic balance of the moment of inertia generated by the elements necessary for detecting the position of the objective lens attached to the objective lens holding member can be easily balanced. (3) Make the optical head more compact. (4)
Improve objective lens position output linearity.

It is possible to detect the objective lens position which makes it possible to solve the above four problems.

Examples of this prior art are factor 7 (island), (b), (C), and FIG. 8 (a).

(b). In FIGS. 7(a), 7(c), 81 is an objective lens holding member. 82 is the center of rotation.

83 is an objective lens. 84 is a light emitting element.

85 is a slit. 86 is a two-split light receiving element.

87 is an actuator mounting base.

88 is an optical disc. Reference numeral 89 denotes a light beam that passes from the light emitting element 84, passes through the slit 85, and reaches the two-split light receiving element 86. 40 is a light beam from a semiconductor laser (not shown). 41 is a light beam spot. 42 is a differential amplifier. 43ii addition amplifier. FIG. 7(,) is a plan view of a conventional example.

79(b) is a sectional view taken along line x-x' in FIG. 7(&). FIG. 7(e) is an electrical circuit diagram for obtaining an objective lens position signal. As shown in the figure, light emitting elements 84 and 8 are attached to the counterweight 46 in FIG.
A slit 85 is arranged to limit the light flux from 4. The light beam from the light emitting element 84 is shaped into a suitable shape by 85 and then reaches a two-split detector 86 . The r-itector 86 has a dividing line perpendicular to the tracking direction. When the center of the objective lens 83 and the optical axis of the light beam 400 from the laser coincide (in the case of eccentricity O), 86m, 86b
If the output of each detector is adjusted to be equal, the spot 89 on 86 will move when the objective lens is decentered, and an output proportional to the objective lens position will be generated as shown in Figure 10. do.

APC (Auto Pow@rCon
Trol) control can be performed to reduce output fluctuations due to temperature changes of the LED and to accurately detect the objective lens position.

Another conventional example is shown in FIGS. 9(a), 9(c).

The conventional light emitting elements shown in FIGS. 7 and 8 are generally LEDs, and the LEDs emit a diverging light beam. Accordingly, in FIG. 9, a collimator lens 47 is added to the objective lens holding member 81, and the light beam 89t'' from the light emitting cord 84 is made into a parallel light beam.This partially improves the linearity of the objective lens position output.

[Problem to be solved by the invention]

However, in the conventional examples described above, LEDs as shown in FIGS. 11, 12, and 13 have been used.

FIG. 11 shows the resin mold type, and the lead pin 54
A chip (light emitting element) 551 is mounted on top, and the whole is molded with a transparent resin 5, such as epoxy resin.

Although the lens portion 53 can be formed to provide directivity, the deviation between the light emission center of the chip 7'55 on the lead pin 54 and the optical axis center of the lens portion 53 is large and is approximately ±0.3 w. , it is difficult to obtain uniform parallel light,
When the lead wire (not shown) is taken out from the lead pin 54, it must be soldered to the resin end A at a distance of about 2 to 3 meters [H], which poses the problem of making it difficult to downsize. FIG. 12 shows a ceramic stem type in which a chip 62 is mounted on a ceramic stem 61 and coated with a translucent resin 63. This example also uses the lead pin G4 as in FIG. 11, which makes it difficult to reduce the size, and the use of ceramics also makes it difficult to reduce the weight.

FIG. 13 shows a camping package tie fy2, in which a chip 72 is mounted on a metal stem 71, and a window is provided, shielded by a companion bag 73. 74 beams - Dovin. The shape of the glass lens 74 of the cage has high directivity, and compared to other pine cages, it has excellent moisture resistance,
Excellent heat resistance and corrosion resistance.

However, because it uses glass and metal, it is inevitably heavy, and it is difficult to produce small, precise parts.

As described above, in the conventional example, there are problems in that it is difficult to accurately position the chip, which is a light emitting element, and the directionality of light emission is also poor, making it difficult to reduce weight and facilitate the removal of lead wires. was.

〔the purpose〕

The present invention was developed in view of the problems of the prior art described above, and its purpose is to make it possible to reduce the size and weight of various optical elements necessary for detecting the position of an objective lens, and to An object of the present invention is to provide an optical information processing device that can further improve the accuracy of position detection.

[Ninth means to solve the problem]

According to the present invention, the above-mentioned object has a movable member that holds an objective lens, the movable member has a flexible printed circuit board whose one end is connected to the 7 members, and the glint A light emitting element and a collimator lens that converts the light beam emitted by the light emitting element into a parallel light beam are fixed to the substrate, and the device includes a light receiving element fixed relative to the movable member. This is achieved by an optical information processing device that detects the position of the objective lens by detecting, with the light receiving element, a parallel beam of light emitted from the light emitting element and passing through a collimator lens.

[Effect]

According to the above means, the light emitting element in the light emitting part for detecting the tracking direction of the objective lens and the collimator that converts the light beam from the light emitting element into a fully parallel light beam are constructed and fixed on the flexible printed circuit board, thereby making it possible to scan the object. It can be lighter in weight than package type or ceramic stem type LEDs.

In particular, since it does not use lead pins and uses a flexible substrate, it has the advantage of being lightweight by the weight of the lead pins, and that it is easy to route the lead wires.

In addition, as in the example described later, when a collimator is glued using the main turn of a flexible printed circuit board as a mark,
When fitting and gluing a flexible printed circuit board into a collimator, the center of the optical axis of the collimator and the center of the light emitting pattern of the light emitting element can be aligned and fixed with high accuracy, so the output of the light receiving section has the effect of excellent linearity. .

〔Example〕

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

FIG. 1 is an exploded perspective view of an objective lens driving device to show an embodiment of the optical information processing device of the present invention.

In FIG. 1, the objective lens holder l is inserted into the support shaft 11 via a bearing 31. As shown in FIG. In the vicinity of the bearing 31, there are attached the objective lens 2, a weight 12 having approximately the same weight as the objective lens 2 in order to maintain the weight balance, and a weight 51 to maintain the weight balance in the vertical direction. A focusing coil 3 is wound around the outer periphery of the objective lens holder 1, and substantially rectangular tracking coils 4m and 4b (not shown 4c and 4a) are attached thereon.

The support shaft 11 is fixed to the ferromagnetic yoke 9 by direct press-fitting or the like. In addition, the yoke 9 has a tracking coil of 4 m, 4
A tracking permanent magnet 7a is disposed near the outer periphery of the objective lens holder l so as to face b and (not shown 4c and 4d).
and 7b, 7c and 7d are fixed respectively.

Further, permanent focusing magnets 6a and 6b are fixedly attached below the tracking permanent magnets 7a to 7d of the yoke 9 so as to face the focusing coil 3. Tracking permanent magnets 71 to 7d and focusing permanent magnets 6 m +
Inner yokes 8m and 8b are provided as opposing magnetic poles of the objective lens holder 1 near the inner periphery of the objective lens holder 1 and facing the inner periphery thereof.

The objective lens driving device according to this embodiment includes a focusing coil 3 and a tracking coil 4.

4b are attached separately, so the 7 orcus permanent magnets 6m and 6b and the tracking permanent magnets 7a to 7
The distance between d and the inner yokes 8a and 8b can be narrowed, increasing the magnetic flux density.

Focusing permanent magnets 6a, 6b, racking permanent magnets 7a to 7d, inner yokes 8a, 8b.

is directly attached to the yoke 9 with adhesive or the like.

Pins 14a and 14b for positioning a cover member (not shown) are provided at the upper portions of the inner yokes 8a and 8b.

In this embodiment, the support shaft 11 is provided with a downward sliding range of the objective lens holder 1 that is limited to approximately 0.8 to 1 - below the focal position of the objective lens 2. A limiter 15 is press-fitted or bonded to the yoke 9 to prevent it from coming into direct contact with the yoke 9 and cause it to be damaged or worn out, and also to maintain a sound-deadening effect.

A parallel light LED 25 according to the present invention is fixed at a position symmetrical about the support shaft 11 of the objective lens 2 shown in the figure, together with the slit 22, in a positioning hole 26 at the lower part of the objective lens holder l. Parallel light LED 25.

It is composed of a flexible printed circuit board 20, a backing plate 23, a light emitting element (not shown) on the flexible printed circuit board 20 (lower part of the figure), and a collimator lens 21 positioned and fixed on the flexible printed circuit board 20.

In this parallel light LED 25, the part A of the flexible printed circuit board 20 is fixed to the outer periphery of the objective lens holder l like the positioning hole 26t-through part D A/, and a land pattern is provided in this part. In invention at least 1
The lead wire 24, which is made of a wire that is longer than a regular wire, is soldered. An elastic member (not shown) such as silicone rubber is mounted on the soldering portion sb to prevent the lead wire 24 from being cut when the objective lens holder 1 moves vertically and horizontally.

FIG. 2 is an exploded perspective view of a parallel light LED 25 according to the present invention. On the yoke 9 side, a two-split sensor (not shown) serving as a light receiving section is provided. From the same figure, backing plate 2
The flexible printed circuit board 20 reinforced with 3 has a positioning land which is concentric or has a point.
A turn portion 26 is provided, and the collimator lens 21 is positioned and fixed using the outer peripheral portion of the land pattern portion 26 as a mark. In front of this, the light emitting element 27 is also electrically fixed using only the positioning land/mother turn portion 28 or further using the positioning recess portion 29 as a mark. 24 is a lead wire composed of twisted wires.

101 and 102 are respectively 7 orcus coils 3 and tracking coils 4 and 4d which are stretched and soldered. 103, the exposed land portion 104 is the positioning hole 26
This is a land for discharging static electricity from the objective lens holder 1 toward the base by contacting and conducting with the inner surface.

FIGS. 3(a) and 3(b) are diagrams for explaining another embodiment of the present invention.

This is a diagram of the positioning F'i of the light emitting element 27 on the flexible printed circuit board 131 in the example shown in FIG. 2.

The part of the Flexi-1 Luglint board 131 reinforced by the backing plate 132 is cut into a circular shape with high precision. The collimator lens 133 is connected to the flexible printed circuit board 13
After being positioned in a lens fixing jig (not shown), it is fitted and fixed to the circular cut part of the flexible print i[131.

As shown by the dotted line 9, the slit 122 is precisely positioned and fixed to the collimator lens 133 on two planes and on the zero or E plane.

In this embodiment, K is used to drive the objective lens.

The support method uses bearing means such as a support shaft and a bearing to slide up and down and rotate left and right. The method of driving the objective lens is not particularly limited.

In this example, the material of the collimator lens is a styrene-based special polymerization type thermoplastic molding resin having the characteristics shown in the table in FIG. However, the present invention is not limited to this, and any material having excellent heat resistance, transparency, and moldability such as polycargenate resin may be used. Bye.

A resin such as a liquid crystal polymer that can also block light through slits? The materials, such as reamer, 4-licargonate, and I-XI, are not limited in terms of percentage.

Although the flexible/lint board is also soldered with υ wire lead wires, for example, the flexible/lint board may be extended and electrically connected directly to the base (not shown).

Further, the present invention does not limit the slit member to be a separate member, and methods such as molding the collimator lens in two colors, leaving it in the shape of a slit and painting the rest with paint are also possible.

Another possible method for positioning the collimator lens on the flexible printed circuit board is to provide a positioning hole or groove in the flexible/lint circuit board, provide a pin-shaped or convex portion on the collimator lens side, and fix it by fitting positioning K. .

Incidentally, it is also possible to do the opposite of the above, with the 1 positioning hole or groove provided on the collimator lens side and the pin-shaped or convex portion 7 provided on the Lexiglusolint side.

〔Effect of the invention〕

As explained in detail above, by configuring and fixing on a flexible printed circuit board a light emitting element in a light emitting section for detecting the tracking direction of an objective lens and a collimator lens that converts the light beam from the light emitting element into a parallel light beam, It is lighter in weight compared to the Can/Mother Cage type and Ceramic Distem type LEDs. In particular, it has the effects of reducing the weight of a rounded lead bin using a flexible substrate without using a lead wire, miniaturizing it, and making it easy to run the lead wire.

When gluing a collimator lens using the mother turn of a flexible printed circuit board as a guide, or when fitting and gluing a flexible printed circuit board onto a collimator lens, the center of the optical axis of the collimator lens and the center of the light emitting turn of the light emitting element are aligned. The linearity (accuracy) of the output from the light receiving section is improved because it can be precisely aligned and fixed with adhesive.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of an objective lens driving device to show an embodiment of the optical information processing device of the present invention, FIG. 2 is an exploded perspective view of a parallel light LED 25 according to the present invention, and FIG. 3 (A)
, tb> is a diagram showing another embodiment of the parallel light LED of the present invention, and FIG. 4 is a tracking sensor. 5(a) = (bl*(cl) is a diagram showing the spot on the detector and a graph showing its differential output, FIG. 6(a) *(bl 7(a) e (b) *(cl is a diagram showing a conventional example, FIG. 8(a); tb+ is a diagram showing a conventional example, FIG. 9 ta) e tb)
-(e) is a diagram showing a conventional example; FIG. 10 is a graph showing the relationship between objective lens position and output; FIGS. 11, 12, and 13 are cross-sectional views each showing a conventional LED; The figure is a table showing the characteristics of resin for thermal qf plastic molding. 1... Objective lens holder, 2... Objective lens, 20
...Flexible printed circuit board, 21...Collimator lens, 22...Slit %25...LED. Figure 1-12 Agent Patent Attorney Minoru Yamashita Heiban lt: Figure 10 Figure 1010 (C) Figure Figure 1 Figure Figure 1

Claims (1)

[Claims] (1) It has a movable member that holds an objective lens, and the movable member has a flexible printed circuit board with one end connected to the member, and the printed circuit board includes a light emitting element and a flexible printed circuit board. A collimator lens that converts the light emitted from the light emitting element into a parallel light beam is fixed thereto, and the device has a light receiving element fixed relatively to the movable member, and the collimator lens emitted from the light emitting element An optical information processing device that detects the position of the objective lens by detecting a parallel light beam that has passed through the light receiving element.