JPH04209327A - Optical disk driving device - Google Patents

Abstract

PURPOSE:To miniaturize a carriage and to stabilize seeking by installing a sensor counter plate under the carriage on the side where the objective lens is mounted on the carriage and installing a positional detection member on the chassis side countering the pattern. CONSTITUTION:A pattern consisting of reflective and non-reflective films of light is constituted on the counter plate 41 by providing the sensor counter plate 41 for positional detection of the carriage 22 under the carriage on the opposite side of the carriage 22 where the objective lens 23 is mounted. Furthermore, detection of a home position of the carriage 22 is carried out by providing a photosensor 42 consisting of a light emitting element and a light receiving element as positional detection members in the part countering a driving chassis 20 countering the pattern part of this counter plate 41. Thus, the counter plate 41 provided with the pattern part for positional detection does not project outside the carriage 22. Because of this, a stable focusing and pulling in of tracking can be carried out without spoiling the weight and rigidity of the carriage 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc drive device, and more particularly to an optical disc drive device equipped with means for detecting the moving position of a carriage.

[Conventional technology]

Conventionally, in optical disk drive devices, it is necessary to accurately detect where the carriage is located on the radius of the optical disk when performing a seek operation to move the carriage in the radial direction of the optical disk, such as trunk detection or tracking control. A linear encoder is normally used for this position detection, and the output of the linear encoder moves the carriage in the radial direction of the optical disk, thereby moving the objective lens to the target position.

In addition, when performing focusing to converge the spot on the track of the optical disc or tracking to position the spot on the track of the optical disc, the home position position is configured in advance in the linear encoder described above. Then, the above-mentioned movement fIr- is performed using that position as a reference.

To explain more specifically, as shown in FIGS. 3(a) and 3(b), the linear scale 4 is mounted on the carriage 2 side,
The first element consists of a light emitting element and a light receiving element. The second two position detection photosensors 5 and 6 are connected to the chassis 10 of the drive device.
The position of the carriage 2 is detected by irradiating light from the light emitting parts of the photosensors 5 and 6 onto the linear scale 4 and detecting the reflected light from the linear scale 4. .

In the figure, reference numeral 1 is an optical disk, 3 is an objective lens, 7 is a reflective part for detecting the home position of the linear scale, 8 is a position detection pattern in which non-reflective parts are arranged at equal intervals, and 9
is a motor for rotating an optical disk.

Here, FIGS. 4(a) and 4(b) show each photosensor 5.
, 6, and FIG.
b) shows the outputs of the second photosensor 6 that detects the position detection pattern 8, in the position detection method having the configuration shown in FIG.

The first photosensor 5 detects the home position, and the second photosensor 6 moves the objective lens 3 to a target trunk position on the optical disk 1.

Incidentally, some recent optical disk drive devices employ a method of directly counting the tracks of an optical disk using a track error signal instead of detecting the position using the second photosensor 6. That is,
It calculates how many tracks it takes to reach the target position from the current position, and counts the number of tracks crossed by the trunk error signal.

However, even with this method, it is essential to detect the reference home position. In other words, in an optical disk drive device, there are eight position detection devices that can directly detect the position of the carriage.

By the way, the photosensor used for the above-mentioned position detection has a configuration as shown in FIGS. 5(a) and 5(b). That is, the photosensor is of a photointerrupter type that includes a light emitting element and a light receiving element, and includes a light emitting part 11a that emits a luminous flux and a light receiving part 11b that receives the luminous flux. Then, as shown in FIG. 5(c), a reflective part 12b and a non-reflective part 12a are provided on the side of the mating member 12, and the light emitting part emits light and the light receiving part detects the reflected light from the mating part. The home position is detected by utilizing the fact that the sensor output is different between the reflective part and the non-reflective part.

That is, as shown in FIG. 5(d), the zero-crossing part of this output (the boundary between the reflective part and the non-reflective part) is compared as the home position, and the carriage is held at this position to move the predetermined track of the optical disc. Focusing and tracking pull-in operations are performed to converge the light spot.

Above, we have described two methods for detecting the position of the carriage: a method in which the home position and track position are detected using two photosensors, and a method in which only the home position is detected using one photosensor. Since either method may be used, in this article, for the sake of simplicity, we will describe only the method for detecting the home position, which will be described later.

Here, a specific example of the configuration of a conventional optical disc drive device is shown in FIGS. 6 and 7.

The optical disk drive device having the configuration shown in FIGS. 6 and 7 is a so-called separate pickup, in which a light source system and a detection system are arranged in a fixed part (drive chassis 20) of the drive device, and an objective lens 23 to optical disc 2
It has a configuration in which it is arranged on a carriage 22 that is movable in the radial direction of 1.

In addition, FIG. 6 is a plan view showing the schematic configuration of the optical pickup when viewed from the optical disk side.
The diagram above line -H is a diagram with the objective lens and focus drive system removed.

Further, FIG. 7 is a diagram showing a cross section taken along the line VI-Vl in FIG. 6.

Here, the objective lens 23 is fixedly held by an objective lens holder 39, supported by the carriage 22 via a plate spring 38 having a surface extending in the tracking direction, and is movable in the focus direction. The motor that drives the objective lens 23 in the focus direction is connected to the drive chassis 2.
A magnetic circuit consisting of a magnet 3G and a yoke 35 is fixed on the o side, and the objective lens holder 3 is placed in the magnetic gap of this magnetic circuit.
It is constructed by arranging a movable coil 37 fixed on the 9 side.

Note that the magnetic gap is formed long in the moving direction of the carriage 22 (X direction in the figure), so that the objective lens 23
The objective lens 23 can perform a focusing operation no matter where in the recording area of the optical disc 21 the objective lens 23 is located.

The drive unit that drives the objective lens 23 in the theta direction (X direction in the figure) has a movable coil 33 i2 placed on the carriage 22 side where the fixed part of the leaf spring 38 described above is arranged, and a magnet on the drive chassis 2o side. A so-called linear motor system is adopted in which the magnetic circuit composed of the magnetic circuit 31 and the yoke 32 is divided into two.

Further, the supporting portion of the carriage 22 includes a guide rail 30 as a theta direction guide member fixed to the driver and drive chassis 20, and the guide rail 30 and the carriage'.
The carriage 22 is configured with a bearing 34 hidden between 3 elements and a guide rail 3.
0 in the theta direction.

Furthermore, the objective lens 2 inside Kiyama J7/C22
A deflection prism 24 for bending the light beam in a direction perpendicular to the light beam of the objective lens 23 is disposed in the lower part of the lens 3.

Note that this configuration is a separate pickup configuration as described above, so a light source system and a detection system (not shown) for recording and reproducing information are arranged and fixed on the drive chassis 20 side. The light beam emitted from the system is deflected by the deflection prism 24 of the carriage 22 toward the objective lens 23 and condensed onto the optical disk 21 via the objective lens 23.

The reflected light from the optical disk 21 is reflected by an objective lens 23.
The information signal is deflected by the deflection prism 24 toward the detection system, where it enters the detection system, where the information signal is detected.

Here, the detection system and the emission light source system are arranged on the right side of the 611ffl carriage and are fixed to the drive chassis 20. Although the configuration of the carriage portion is different from that shown in FIG. 6, FIG. 8 shows a diagram of an apparatus having the same configuration of the detection system and the output light source system 45 as a reference example.

By the way, in FIGS. 6 and 7, the home position detection device of the carriage 22 is shown in FIG.

First, the sensor facing plate 28 is fixedly placed on the carriage 22 side. This sensor facing plate 28 is a T-shaped plate having a long plate fixed in the theta direction to the tip of a plate extending from the carriage 22 through the upper part of the seek movable coil 33 to the outside of the outer yoke 35a of the yoke 32. It is assumed that the pattern 29 is shaped like a letter and includes a reflective portion and a non-reflective portion on the plate side of the distal end that is elongated in the theta direction. The pattern 29 consisting of one reflective part and one non-reflective part is like a plate material with a film attached thereto.

A photosensor support stand 27 is fixed on the side of the drive chassis 20 facing the pattern 29 consisting of reflective parts and non-reflection parts. A photosensor 25 consisting of an element and a light receiving element is fixed.

Now, by providing the home position detection device with the above configuration, when the carriage 22 moves in the theta direction, a zero cross point similar to that shown in FIG. 5(d) can be detected from the output of the photosensor 25. , the home position is detected from this zero cross point, and the carriage 22
is held at the home position, and focusing and tracking of the optical spot on the optical disk 21 can be performed.

Note that the focusing operation is performed by the motor that drives the objective lens 23 mentioned above, but the tracking operation during recording and reproducing information is performed using, for example, a galvanometer mirror system as shown in FIG. This galvano mirror system is provided between the carriage 22 and the light source/detection system 45, and is composed of a mirror 61, a mirror holder 63 to which the mirror 61 is fixed, and a plate spring 62 that holds the mirror holder 63. The rotating mirror base 60 is supported through the rotating mirror base 60, a magnetic circuit consisting of a magnet 67 and a yoke 66 fixed to the rotating mirror base 60 side, and a movable coil 68 fixed to the mirror holder 63 side vibrate the mirror. and a light emitting element 64 such as an LED fixed to the mirror holder 63 side.
The mirror 61 is driven in accordance with a tracking error signal, and has a pressure detection section that detects the vibration state of the mirror. It is designed to perform tracking operations. Note that this galvano mirror system is arranged on the side of a fixed part such as the drive chassis 20.

[The problem that the invention aims to solve]

An example of the configuration of a conventional optical disc drive device has been described above, but in one illustrated example of the optical disc drive device,
As shown in FIGS. 6 and 7, the position pressure detection part of the carriage 22 is located at the outer yoke 35 of the yoke 32 of the seek motor.
It was placed outside of a. However, in a placement position such as the second one.

There is a disadvantage that the moving part during seek becomes larger by the size of the sensor facing plate 28, and the drive device becomes six inches larger in the Y direction in the figure.

Furthermore, since the mechanism for focusing the objective lens 23, especially the movable coil 37 and the leaf spring 38, move together with the objective lens 23 in the focusing direction (two directions in the figure), the sensor facing plate 28 gets in the way of the movement. However, the focusing mechanism must be provided considerably above the sensor facing plate 28, and there is also the problem that the sensor facing plate 28 affects the height of the drive device.

Furthermore, since the sensor facing plate 28 extends from the carriage 22 in a cantilevered manner, the rigidity of the carriage 22 is reduced, and the control accuracy for positioning the carriage, that is, the seek operation, is poor. In addition, when controlling the carriage to hold the home position used when focusing and tracking the optical disc 21, the control signal is detected at the tip of the beam as described above, so the detection M degree is improved. In order to do this, it is necessary to use a material with high rigidity for the sensor facing plate 28, which causes the weight of the carriage 22 to become heavy, and also causes the sealing and opening during access. Note that if a lightweight material with low rigidity is used for the sensor facing plate 28, the tip of the sensor facing plate 28 will vibrate, making it difficult to control the hold of the carriage 22 to the home position, resulting in problems such as focusing, track retraction, etc. The problem arises that it becomes impossible to do so.

The present invention has been devised in view of the drawbacks of the conventional devices described above, and aims to reduce the size and weight of the carriage of an optical disk drive device, stabilize seek control, stabilize optical spot focusing, and stabilize tracking pull-in. The company has pledged to make optical disk drive devices smaller and thinner.

[Means for solving Section 2] In order to achieve the above agreement, five light sources: ±, a device for optically recording information on an information recording carrier or reading information recorded on an information recording carrier, which uses a light source. , an objective lens for converging the light flux from the second light source onto the information record carrier; a pressure detection section for detecting the pressure of the reflected light from the information record carrier;
In an optical disk drive device including a carriage supported so as to be movable in the direction of the carrier and on which the objective lens is mounted, there is a reflectance of light on the side of the carriage opposite to the side on which the objective lens is mounted. Alternatively, a pattern in which the transmittance changes is arranged, and an optical position detection member for emitting and detecting light is arranged on the chassis side of the drive device facing the pattern.

Further, in the above-mentioned optical disk drive device, the position detection member is arranged on the substrate on which the circuit pattern is arranged, and the chassis of the drive device facing the pattern on the carriage side is provided with the position detection member on which the pattern on the carriage side is arranged when the carriage moves. A window portion of a size approximately corresponding to the movement range is provided, and the board on which the position detection member is arranged is fixed so as to cover the Z section of the chassis. ! It is characterized by being

[For production]

According to the present invention, a pattern in which the reflectance of light changes or the transmittance changes is arranged on the lower surface side of the carriage opposite to the side on which the objective lens is mounted, and the drive device faces the pattern. By placing two optical position detecting members on the chassis side of the system, the position detecting pattern part can not protrude outward from the carriage in a cantilever manner as in conventional devices. Because it disappears,
The weight and rigidity of the carriage are not impaired, and the optical disc drive device can be made smaller.

Further, the position detection member is placed on the board on which the circuit pattern is arranged, a window is provided on the chassis side of the drive device that faces the pattern on the carriage side, and the board on which the position detection member is arranged is placed on the window of the chassis. Since the position detecting member is fixedly placed so as to cover the optical disc drive device, the position detecting member hardly protrudes from the chassis surface, the height direction of the optical disk drive device is less restricted by the position detecting member, and the device can be made thinner.

〔Example〕

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1(a) is a plan view showing a schematic configuration of essential parts of an optical disk drive device showing an embodiment of the present invention, and FIG. 1(b) is a cross-sectional view taken along line 11B in FIG. 1(a). It is a diagram.

The optical disc drive device has the configuration shown in FIG.

The optical disc drive device is configured in substantially the same manner as the conventional optical disk drive device having the configuration shown in FIGS. 6 and 7 described above.
A focus drive unit that drives the objective lens 23, an objective lens support unit that supports the objective lens 23, and a carriage 2
Components with the same reference numerals as in FIGS. 6 and 7, such as a support portion that supports the drive unit 2 movably with respect to the drive chassis 20 and a drive portion that drives the drive unit in the theta direction, have the same functions and effects. Therefore, the explanation will be omitted.

In addition, the reference numeral 45 in the figure is a light source system and an aspect ratio system for recording and reproducing information that are fixed to the chassis 2o side.
A tracking device such as a galvano mirror system shown in the figure is also included.

In addition, in FIG. 1(a), the diagram above H-Hl is a diagram excluding the objective lens and focus drive system.

Here, the optical disk drive device according to the present invention is characterized in that a sensor facing plate 41 for detecting the position of the carriage 22 is provided on the lower surface of the carriage 22 on the side opposite to the side on which the objective lens 23 is mounted. A pattern consisting of a light reflecting and non-reflecting film is formed on the opposing plate 41,
A photosensor 42 consisting of a light emitting element and a light receiving element is provided as a position detecting member on the opposite part of the drive chassis 20 side facing the pattern part of the sensor facing plate 41 to detect the home position of the carriage 22. be.

This will be explained in more detail below.

As shown in the figure, the sensor facing plate 41 provided on the carriage 22 side is fixedly placed 2 on the lower surface side of the carriage further below the deflection prism 24 on the side opposite to the side on which the objective lens 23 is mounted on the carriage 22.

On the surface of the second sensor facing plate 41 facing the photosensor 42, a pattern portion consisting of a reflective film and a non-reflective film is formed, similar to the conventional technology, and the boundary between the reflective film and the non-reflective film, that is, the sensor output. The carriage 22 is held with the zero cross point as the home position, so that the focusing of the light spot onto the optical disk 21 and the tracking pull-in operation can be performed.

Further, as shown in FIG. 2, a window 44 of a size approximately corresponding to the movement range of the carriage side pattern when the carriage is moved is provided at a position facing the sensor facing plate 41 on the drive chassis 2o side. and this window 4
4, a photosensor substrate 43 to which a photosensor 42 is attached is fixedly arranged. A conductive pattern 46 is formed on this photosensor substrate 43 so that power can be supplied to the outside. In addition to the conductive pattern 46, it is also possible to mount electrical components such as resistors and capacitors on the substrate 43 as long as they are of a size that does not interfere with the movement of the carriage 22.

Now, in the optical disc drive device having the position detection procedure configured as described above, the drawbacks of the conventional device can be sufficiently eliminated.

That is, by arranging the photosensor facing plate 41 on the lower surface side of the carriage 22 and arranging the photosensor 42 at a position of the drive chassis 20 facing the reflective/non-reflective pattern portion of the sensor facing plate 41, as shown in FIG. Since the sensor facing plate does not protrude from the carriage as in the conventional device shown in FIG. 7, the space required for this protruding part is no longer necessary, and the drive device can be made smaller by this space. I can do it.

Further, since the sensor facing plate 41 is arranged at a position where it does not affect the active part of the focusing actuator at all, it does not affect the design of the drive device in the height direction (two directions in the figure). That is, in the configuration shown in FIG. 1, the constraint in the height direction of the carriage 22 is the movable coil 33 that constitutes the seek motor, and the position detection sensor portion is restricted by the two movable coils 33 of the seek motor. Since it is located in the open position, it has almost no effect.

Furthermore, in the configuration of the present invention, since the sensor opposing plate 41 is fixed to substantially the entire lower surface of the carriage 22 (the surface facing the drive chassis 20), the sensor opposing plate 41 hardly affects the rigidity of the carriage. None. Therefore, stable focusing and tracking can be achieved.

Further, since the sensor facing plate 41 can be fixed on the entire surface of the carriage in this way, the sensor facing plate 41 can be made extremely thin, so that it does not affect the weight of the carriage 220.

Furthermore, in the present invention, a window 44 is provided on the chassis 20 side of the drive device as shown in FIG. There is no possibility of intrusion of anything that would affect signal deterioration.

In the above explanation, only the case where the home position is detected by providing reflective and non-reflective patterns on the sensor facing plate 41 has been described, but the sensor facing plate 41 on the side of the carriage 22 may be formed of equally spaced bright and dark patterns. A linear scale is provided, and a second scale is provided on the photosensor board 43 on the chassis side.
It is also possible to provide a photo sensor and use it as a linear scale.

〔Effect of the invention〕

As described above, in the optical disk drive device according to the present invention, the sensor facing plate has a pattern in which the reflectance of light changes or the transmittance changes on the lower surface side of the carriage opposite to the side where the objective lens is mounted. By arranging a position detection member consisting of a photosensor that emits and detects light on the chassis side of the drive device facing the pattern, the sensor facing plate having the pattern portion for position detection is different from that of the conventional device. Since it no longer protrudes outward from the carriage in a cantilevered manner, stable focusing and tracking retraction can be achieved without sacrificing the weight or rigidity of the carriage.

Furthermore, since the sensor facing plate does not protrude from the carriage, it is possible to easily downsize the optical disc drive device.

In addition, the position detection member is placed on the board on which the circuit pattern is arranged, and a window is provided on the chassis side of the drive device that faces the pattern on the carriage side, and the board on which the position detection member is arranged is placed on the chassis side. Since the first position detecting member is fixedly arranged so as to cover the window, it hardly protrudes from the chassis surface, so that the height direction of the optical disk drive device is less restricted by the position detecting member, and the device can be made thinner.

Therefore, according to the present invention, the carriage of an optical disc drive device equipped with a carriage position detection member can be small and
It can reduce weight, stabilize seek control, focus the light spot, and stabilize tracking pull-in.
Moreover, the optical disc drive device can be made smaller and thinner.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing a schematic configuration of main parts of an optical disk drive device showing one embodiment of the present invention, and FIG.
) is Mlm (a) I-1,! A cross-sectional view, and FIG. 2 shows the mounting of the position detection member of the same optical disk drive device as shown in Example 2.
Figures 5 to 5 show the method of detecting the position of the carriage, Figure 6.
The figure is a plan view showing a schematic configuration of essential parts of an optical disk drive device as an example of the prior art, FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6, and FIGS. - A reference diagram for explaining the i12 overlap position a of the galvanometer mirror system for racking and the light source system/detection system. 2Q... Chassis of the drive device, 21... Optical disk, 22... Carriage, 23... Objective lens, 24... Deflection prism, 41... Position detection pattern equipped with a sensor facing plate, 42...photo sensor as a position detection member, 43... sensor substrate, 44... window section, 45... light source and detection section,
46...Circuit pattern, X...Theta direction. 7'f) 5 Illustrations I Act 7 Daysai 6 Vision (and) Procedural amendment written form) % form % 1. Display of the incident 1990 Patent Application No. 65779 2. Name of the invention Optical disk drive device 3. Amendment Relationship with the case of the patent applicant Address: 1-3-6 Nakamagome, Ota-ku, Tokyo Name (67)
4) Ricoh Co., Ltd. -4, Agent 5, Date of amendment order - Shipping address: October 22, 1991 6, "Brief explanation of drawings" column of the specification subject to amendment. 7. Contents of amendment (1) "Fig. 8..." on page 23, lines 15 to 17 of the specification was changed to [Fig. 8 (a) and (b) are galvanometer mirrors for tracking]. FIG. 3 is a diagram for explaining the arrangement positions of the system and the light source system/detection system. ”.

Claims (1)

[Scope of Claims] 1. A device for optically recording information on an information recording carrier or reading recorded information, comprising a light source and an objective lens for converging a light beam from the light source onto the information recording carrier. an optical disc drive device comprising: a detection unit that detects reflected light from the information recording carrier; and a carriage supported movably in a radial direction of the information recording carrier and on which the objective lens is mounted. , a pattern in which the reflectance or transmittance of light changes is arranged on the opposite side of the carriage to the side where the objective lens is mounted, and an optical position is provided for emitting and detecting light to the chassis side of the drive device facing the pattern. An optical disc drive device characterized in that a detection member is arranged. 2. The optical disc drive device according to claim 1,
The position detection member is arranged on the board on which the circuit pattern is arranged, and the chassis of the drive device facing the pattern on the carriage side has a size approximately corresponding to the movement range of the pattern on the carriage side when the carriage moves. 1. An optical disk drive device, wherein a window portion of the chassis is provided, and the substrate on which the position detection member is disposed is fixedly arranged so as to cover the window portion of the chassis.