JP3166047B2 - Optical pickup device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device applied to a compact disk player, a laser disk player, a magneto-optical disk device, and the like.

[0002]

2. Description of the Related Art As is well known, an optical pickup device
Laser light from a light source is guided to an objective lens by an optical system, and the objective lens focuses the laser light and irradiates an information track on an optical disk. Further, by detecting the reflected light from the optical disc with a light receiving element or the like, information recording / recording is performed.
It is for regenerating.

As an example, Japanese Patent Application Laid-Open No. 2-68730 discloses that
A technique related to an optical pickup device is disclosed.

[0004]

In order to accurately transmit the reflected light from the optical disk to the detecting means, it is necessary to make the optical path of the emitted light of the laser light parallel to the moving direction of the objective lens.

FIG. 6 is an explanatory view showing an example of the operation of the optical pickup device. Reference numeral 50 denotes an objective lens, 51 denotes a fixed optical system having a light source and a photoelectric conversion element for detecting reflected light, and 52 denotes a fixed optical system. 5 shows a deflecting prism that changes the optical path of light emitted from the system toward the objective lens 50.

As shown in FIG. 6, when the moving direction M ₀ of the objective lens 50 is deviated from the optical path of the outgoing light deflected by the deflecting prism 52, the optical path L of the reflected light from the optical disk (not shown). ₁ changes depending on the moving position of the objective lens 50. Therefore, there occurs a problem that the reflected light does not enter the fixed optical system 51 through a certain optical path.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an optical pickup device provided with a mechanism for making an optical path of emitted light and a moving direction of an objective lens parallel. .

[0008]

[0009]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The present invention includes an objective lens for forming a light spot on the information recording surface of an information recording medium, a carriage for holding the deflection means or the like for guiding the light to the objective lens and the objective lens, the carriage of the information recording medium movable optical system comprising a seek base which movably supports the radial direction, and a front
Serial a light source for generating light to be sent to the objective lens, the optical pickup apparatus comprising a fixed optical system having a detection means that detects by receiving reflected light from the information recording medium, before
Serial rotatably mounted seek based on the drive base, further wherein on the rotation axis in the seek based on, features a light emitted from the fixed optical system that secures the deflecting prism for guiding the deflecting means in the carriage And

Further, the present invention is characterized in that a light receiving element for detecting light from a light source transmitted through the deflecting prism is fixed to a seek base.

Further, the light receiving element has at least two light receiving parts, and the light receiving element is provided with a detecting means for detecting a difference of a photoelectric conversion signal from the light receiving part and detecting a light receiving position on the light receiving element. It is characterized by.

Further, a condensing lens for condensing outgoing light from a fixed optical system provided between the deflecting prism and the light receiving element on the light receiving element, and receiving light on the light receiving element from an output of the light receiving element. Detecting means for detecting the position and the amount of received light.

Further, a cylindrical projection provided on the lower surface of the deflection base fixing portion of the seek base, a fitting hole of the cylindrical projection provided on the drive base and serving as a center of rotation of the seek base, And a screw hole corresponding to the elongated hole formed on the drive base, the elongated hole being formed on the seek base for rotating and fixing at a predetermined position.

[0014]

[0015]

By employing [acting] The configuration, the present invention, the positional relationship between the moving direction of the deflecting surface and the carriage of the deflecting prism while maintaining constant movement of the optical path of the objective lens of the light emitted from the fixed optical system The direction can be adjusted. That is, for example, when the seek base is rotated by the angle Δθ, as shown in FIG. 7, the moving direction M ₀ of the deflecting prism 4 and the objective lens is rotated by Δθ in the same direction, whereas the optical path L _{0 of the} emitted light is Rotates 2Δθ. Therefore, if the seek base is rotated, there is an angle θ at which the moving direction of the objective lens is parallel to M ₀ ′ and the optical path L ₀ ′ of the emitted light at a certain angle. Then, the adjustment is completed by fixing the seek base when rotated by the angle θ.

Further, by providing the light receiving element on the seek base, the amount of rotation of the seek base can be controlled by the output of the light receiving element. Therefore, before attaching the movable optical system to the main body, for example, a laser light from a laser light source corresponding to a fixed optical system is incident on the movable optical system, and the optical path of the laser light and the moving direction of the objective lens are parallel. The output of the light receiving element is detected and recorded. Then, the movable optical system is placed on the apparatus main body, and the position is adjusted and fixed so that the light receiving element is detected and output in advance, so that the optical path of the light emitted from the fixed optical system is fixed. The movable optical system is installed such that the direction of movement of the objective lens is parallel to the moving direction of the objective lens.

Further, since the light receiving element has at least two light receiving parts, and by taking the difference between the signals from these light receiving parts, the irradiation position on the light receiving element of the fixed optical system can be detected. The relative tilt amount between the seek base and the fixed optical system can be determined.

Further, by providing a condenser lens between the deflecting prism and the light receiving element, a brighter and smaller light spot is formed on the light receiving element.

Further, by providing a cylindrical projection on the seek base and fitting the cylindrical projection into a reference hole provided on the drive base, the seek base becomes rotatable, and the rotation causes the optical path of the light emitted from the fixed optical system to be adjusted. After making the moving direction of the objective lens parallel, the position adjustment is completed by screwing the seek base to the drive base through the elongated hole.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a schematic configuration of an optical disk device including an embodiment of the present invention, wherein 1 is an optical disk, and 2 is a fixed optical system. Inside the fixed optical system 2, there are provided a light source, a collimating lens that converts diffused light from the light source into parallel light, a light receiving element that detects reflected light from the optical disk 1, and the like.

Reference numeral 3 denotes a movable optical system. Reference numeral 4 denotes a deflecting prism, 5 denotes an objective lens, 6 denotes a carriage, 7 denotes a seek base, 8 denotes a seek rail, 9 denotes a light receiving element, and 10 denotes a condenser lens. The carriage 6 includes an actuator (not shown) for supporting the objective lens 5 and performing a tracking and focusing operation, and a reflection mirror (described later) for guiding light from the fixed optical system 2 to the objective lens 5. Is provided.

The seek base 7 is formed with seek rails 8, 8, and the carriage 6 is mounted on the seek rails 8, 8 so as to move linearly. Further, a deflection prism 4 is provided on the seek base 7, and a light receiving element 9 is provided beside the deflection prism 4.
A condensing lens 10 is provided on a side surface of the deflecting prism 4 on the light receiving element 9 side.

The parallel light emitted from the fixed optical system 2 is deflected by the deflecting prism 4 and guided to a later-described reflecting mirror in the carriage 6 (hereinafter, particularly the deflecting prism 4).
The optical path of the outgoing light between the optical axis
). A part of the parallel light passes through the deflecting prism 4 as it is, is condensed by the condenser lens 10, and is sent to the light receiving element 9.

Reference numeral 11 denotes a pair of coils wound on a bobbin, which is a rectangular parallelepiped cylindrical body. The coils 11, 11 are fixed to both side surfaces of the carriage 6.

The movable optical system 3 configured as described above is screwed and fixed on the drive base 14 through the fan-shaped elongated holes 13 together with the fixed optical system 2 and the spindle motor 12 for driving the optical disk 1 to rotate. You.

15 passes through the coil 11 and the seek rails 8 and
The inner yoke 16 installed in parallel with 8, the inner yoke 15
At both ends, a U-shaped outer yoke fixed so as to cover the coil 11 is shown. Reference numeral 17 denotes a permanent magnet attached to the outer yoke 16 so as to face the coil 11. The outer yokes 16, 16 are fixed to the drive base 14. Then, the carriage 6 is driven by the action of the magnetic force of the coil 11 and the permanent magnet 17.

FIG. 2 is a sectional view taken along the line AA of FIG. 1 showing a state in which the seek base 7 is mounted. Reference numeral 18 denotes a cylindrical projection formed on the lower surface of the seek base 7 and coaxial with the central axis of the deflecting prism 4. , 19 are formed in the drive base 14, a reference hole into which the projection 18 fits, 20 is formed in the drive base 14 ,
A screw hole for fixing the seek base 7 with the screw 21 through the elongated hole 13 is shown.

The seek base 7 is rotatable about the reference hole 19 by the length of the elongated hole 13.

FIG. 3 is a sectional view taken along the line BB of FIG.
A hard sphere 23 interposed between the carriage 6 and the seek rail 8 and smoothing the seek movement of the carriage 6 is used to transfer the light emitted from the fixed optical system 2 deflected by the deflecting prism 4 shown in FIG. 3 shows a reflecting mirror for guiding.

As shown in FIG. 3, the movable optical system 3 is installed by fixing the seek base 7 to the drive base 14. Further, a slight allowance is provided between the inner peripheral surface of the coil 11 and the outer peripheral surface of the inner yoke 15 so that the seek base 7 does not come into contact with each other by a rotational operation for position adjustment described later. I have.

Next, the drive base 14 of the seek base 7
The work of attaching to the device will be described.

As described above with reference to FIG. 7, the optical path L ₀ (optical axis L ₀ ) of the light emitted from the fixed optical system 2 and the moving direction M ₀ of the objective lens 5 (the description will be simplified below). when "moving shaft" referred to.) and do not match for, so that the optical path L ₁ of the reflected light is not constant. Therefore, it is necessary to know the amount of deviation between the optical axis L ₀ and the movement axis M ₀ in advance.

FIG. 4 is an explanatory diagram for explaining an apparatus and an operation procedure for detecting the above-mentioned shift amount.
Denotes a light source attached to a jig (not shown), and 25 denotes a collimating lens that converts light from the light source 24 into parallel light. This light source 24,
The collimator lens 25 corresponds to the fixed optical system 2 shown in FIG. 26 denotes a hole provided in the jig, into which the projection 18 shown in FIG. 2 is fitted. This hole 26 corresponds to the reference hole 19 shown in FIG. Reference numeral 27 denotes a jig for condensing the reflected light transmitted through the deflecting prism 4 in the reflected light from a reflecting plate (not shown) provided on the jig corresponding to the optical disk 1 shown in FIG. Reference numeral 28 denotes a light-receiving element for detecting light from the condenser lens 27. The light receiving element 28 uses the same light receiving element as the light receiving element 9 shown in FIG.

FIG. 5 is an explanatory diagram showing the configuration of the light receiving element 9 and the light receiving element 28. Since the light receiving element 9 and the light receiving element 28 have the same configuration, only one of the light receiving elements 9 will be described.
9a and 9b indicate photoelectric conversion elements, and 9c indicates a dividing line separating the photoelectric conversion element 9a and the photoelectric conversion element 9b. The light-receiving element 9 has a condenser lens 10 (a condenser lens 27 for the light-receiving element 28).
As a result, a light spot larger than the dividing line 9c is formed.
The light receiving element 9 is connected to a difference circuit for calculating a difference between the outputs of the photoelectric conversion elements 9a and 9b.

Next, the working procedure will be described. First,
The movable optical system 3 is mounted on a jig, the light source 24 emits light, and the deflecting prism 4 is irradiated with parallel light. Next, the seek base 7 is rotated, and the carriage 6 is further linearly moved, and the output of the light receiving element 28 at that time is detected. Optical axis L by light source 24
And the moving axis M is shifted, the output B of the light receiving element 28 changes. Next, rotation and linear movement are repeated,
28 is adjusted to a position where the output B becomes constant.

When the adjustment is completed, the output A of the light receiving element 9 at that position is recorded.

Next, the movable optical system 3 is placed on the drive base 14 by removing the movable optical system 3 from the jig and fitting the projection 18 into the reference hole 19 on the drive base 14. The fixed optical system 2 is fixed to the drive base 14 in advance, and the fixed optical system 2 is positioned and fixed so that the emitted light is directed toward the reference hole 19.

Then, the parallel light is emitted from the fixed optical system 2 and the deflecting prism 4 is irradiated with the parallel light. Next, the seek base 7 is rotated, and adjustment is performed so that the output A of the light receiving element 9 matches the output recorded in the adjustment by the jig.

When the adjustment is completed, the seek base 7 is fixed to the drive base 14 by fixing the screw to the screw hole 20 via the elongated hole 13 at that position.

The present embodiment has the following operational effects by being configured as described above.

First, since the fixed optical system 2 and the movable optical system 3 are independent units, they are assembled and adjusted in units, and then mounted on the apparatus main body. Become. Further, when a defect or breakage occurs, the unit can be replaced in units, so that the yield or the serviceability can be improved.

Since the deflecting prism 4 is fixed on the central axis of the projection 18, when the movable optical system 3 is mounted on the drive base 14, the deflecting prism 4 is inevitably on the central axis of the reference hole 19. Will be located. Therefore, the reference hole 19
By setting the position where the fixed optical system 2 is fixed by using the index as an index, when the fixed optical system 2 and the movable optical system 3 are mounted on the drive base 14, the parallel light from the fixed optical system 2 The position is adjusted so that the deflection prism 4 can be accurately irradiated.

Further, by rotating the movable optical system 3 about the reference hole 19, the adjustment can be performed so that the optical axis L and the moving axis M are parallel. Therefore, the optical disk 1
Can be adjusted so that the optical path of the reflected light from
The reflected light can be detected accurately. Furthermore, since the adjustment between the optical axis L and the movement axis M is performed by the fine movement adjustment of the movable optical system 3, the fixed optical system 2 can be directly and strongly fixed to the drive base 14. . Therefore, the movement of the fixed optical system 2 or the optical components inside the fixed optical system over time is reduced, and the reliability of the device is improved.

Since the deflecting prism 4 is fixed on the center axis of rotation, the light emitted from the fixed optical system 2 always irradiates a fixed point on the deflecting surface. The shift of the reflection position of the emitted light that occurs can be reduced.

The seek base 7 is provided with a deflecting prism 4.
Is provided, the amount of rotation of the seek base 7 can be made to correspond to the output of the light-receiving element 9 by providing the light-receiving element 9 for receiving the parallel light from the fixed optical system 2 that has passed through the light-receiving element 9. Also, it can be used as a monitor of the light emitted from the fixed optical system 2.

Further, the light receiving element 28 provided on the jig has two photoelectric conversion elements 28a and 28b, and the difference between the outputs of the two photoelectric conversion elements 28a and 28b is detected, whereby the light receiving element 28 on the light receiving element 28 is detected. The position of the light spot can be detected. Therefore, if the formation position of the light spot is greatly shifted,
Since the moving direction of the objective lens 5 and the radial direction of the optical disc 1 are largely displaced, defective products can be determined at the time of rotation adjustment of the movable optical system 2.

Further, by providing the condenser lens 10 between the deflecting prism 4 and the light receiving element 9, the diameter of the light spot formed on the light receiving element 9 is reduced, so that the light receiving area may be small. Further, a highly sensitive output can be detected.

In the present embodiment, the position is adjusted so that the output A of the light receiving element 9 becomes 0 after the output B of the light receiving element 28 is adjusted to be constant. And the movable optical system 3 is placed on the drive base 14,
When performing the position adjustment, the rotation may be adjusted so that the output A of the light receiving element 9 becomes zero.

[0049]

The present invention has the following effects by being configured as described above.

[0050]

According to the first aspect of the present invention, the reflected light from the optical disk can return to the fixed optical system through a stable optical path, and an accurate optical pickup can be realized.

According to the second aspect of the present invention, the output of the photoelectric conversion element detected when the position of the optical path of the fixed optical system and the moving direction of the objective lens are adjusted by another adjustment jig is output to the fixed optical system in the apparatus main body. Can be used as a reference signal at the time of adjusting the position of the movable optical system with respect to, so that the position adjustment of both can be easily performed. It can also be used as a monitor for the amount of light emitted from the fixed optical system.

According to the third aspect of the present invention, since the light receiving position on the photoelectric conversion element can be detected, the relative tilt amount between the seek base and the fixed optical system can be determined from the output, and the amount of rotation required for adjustment can be determined. And the direction can be known, so that the adjustment is easy.

According to the structure of claim 4 , the photoelectric conversion element generates an output signal with high sensitivity, and the position where the light spot is formed becomes clearer.

According to the fifth aspect, even when the seek base is rotated and adjusted, the irradiation position of the light emitted from the fixed optical system on the deflecting surface of the deflecting prism becomes constant, and the optical path is enlarged by the rotation of the seek base. It will not shift. After the adjustment, the seek base can be easily fixed to the apparatus main body.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an optical disk device according to one embodiment of the present invention.

FIG. 2 is a view showing a state in which a seek base is mounted; FIG.
It is A sectional drawing.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

4 is a plan view of the movable optical system shown in FIG. 1 for explaining a configuration of a jig for making an optical path of emitted light and a moving direction of an objective lens parallel, and an adjustment operation.

FIG. 5 is an explanatory diagram illustrating a configuration of a light receiving element in FIGS. 1 and 3.

FIG. 6 is an explanatory diagram for explaining a problem of a conventional optical pickup device.

FIG. 7 is an explanatory diagram illustrating the principle of adjusting the optical path of emitted light and the moving direction of an objective lens according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Fixed optical system, 3 ... Moving optical system, 4 ... Deflection prism, 5 ... Objective lens, 6 ... Carriage, 7 ... Seek base, 8 ... Seek rail, 9
... Light receiving element, 10 ... Condenser lens, 13 ... Long hole, 14 ... Drive base, 18 ... Protrusion, 19 ... Reference hole, 20 ... Screw hole, 21 ... Screw.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 7/08 G11B 7/085

Claims (5)

(57) [Claims] 1. An objective lens for forming a light spot on an information recording surface of an information recording medium, and the objective lens and the objective lens.
A carriage for holding the deflection means or the like for guiding the light to the lens, the movable optical system comprising a seek base for movably supporting the carriage in the radial direction of the information recording medium, and pre
Rotating a light source for generating light to be sent to the serial objective lens, the optical pickup apparatus comprising a fixed optical system having a detection means that detects by receiving reflected light from the information recording medium, said seek base on the drive base Mounted as possible
And further fixed on the rotation axis on the seek base.
Light emitted from the constant optical system is sent to the deflection unit in the carriage.
An optical pickup device, wherein a guiding deflecting prism is fixed. 2. A light from a light source transmitted by a deflecting prism.
The light receiving element to be detected is fixed to the seek base.
The optical pickup device according to claim 1, wherein 3. A light receiving element comprises at least two light receiving portions.
A photoelectric conversion signal from the light receiving portion to the light receiving element
The light receiving position on the light receiving element.
3. The optical pickup device according to claim 2, further comprising a detecting unit . 4. A light source provided between a deflecting prism and a light receiving element.
Focusing outgoing light from the fixed optical system on the light receiving element
A condenser lens and the light receiving element based on an output of the light receiving element.
Detecting means for detecting the light receiving position and the light receiving amount on the
The optical pickup apparatus according to claim 2 or 3, wherein further comprising a. 5. The lower surface of a seek-based deflection prism fixing part.
On the drive base and the cylindrical projection on the drive base.
And the cylinder serving as a center of rotation of the seek base
Rotating the seek base with the fitting hole of the projection, and
Slots formed on the seek base to be fixed in place
And the slot corresponding to the slot formed on the drive base.
The optical pickup apparatus according to claim 1, characterized by having a threaded hole that.