JP2550809Y2 - Optical recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention relates to an optical recording apparatus for recording and reproducing information by irradiating a beam from a light source such as a gas laser or a semiconductor laser to an optical recording medium, and in particular, to an optical recording apparatus. The present invention relates to an improvement in an optical recording apparatus in which focus control accompanying a surface shake of an optical recording medium or the like is simple.

[Conventional technology]

As an optical recording apparatus of this type, as shown in FIG. 11, a light source (a) such as a semiconductor laser, a collimator lens (b) for converting a diffused beam from this light source (a) into a parallel beam, A beam shaping prism (c) that converts the beam spot shape from an elliptical shape to a substantially circular shape, and separates an incident beam incident on the optical recording medium (d) from a reflected beam reflected from the optical recording medium (d). Beam splitter (e), and a quarter-wave plate (f) that passes through the beam splitter (e) and converts a linearly polarized beam into circularly polarized light.
And an objective lens (g) movably provided to converge the beam that has passed through the quarter-wave plate (f) on the converging surface of the optical recording medium (d), and an objective lens (g) separated by the beam splitter (e). The principal part is constituted by a cylindrical lens (i) for causing the reflected beam to enter a four-division PIN photodiode (h) for obtaining a tracking error signal, a focusing error signal, and a reproduced RF signal. As an optical recording medium (d) incorporated in the apparatus, a transparent circular substrate (d1) and a recording layer provided on one side of the substrate (d1) as shown in FIGS. It is known that (d2) and a protective layer (d3) provided on the entire surface of the recording layer (d2) constitute a main part thereof.

In this type of optical recording apparatus, information is recorded spirally or concentrically on a recording layer (d2) of an optical recording medium (d), and an objective lens (g) is used to reproduce the recorded information. Is moved in the radial direction of the optical recording medium (d) (that is, in the track direction), and the optical head is moved in the focus direction in order to cope with surface deflection of the optical recording medium (d). Had to be done.

For this reason, in this type of optical recording device, the thirteenth
As shown in the figure, a movable body (k) on which an optical head (He) is mounted and which is guided by a guide member (j) and moves in a track direction (direction indicated by an arrow X in the figure); ), A track control drive coil (mt) that moves the movable body (k) in the track direction with energization
And a focus control drive coil (mf) attached to the optical head (He) for moving the optical head (He) in the focus direction (the direction indicated by arrow Y in the figure) upon energization. The drive system which constitutes was incorporated.

However, in an optical recording apparatus in which this type of drive system is incorporated, a focus control drive coil (mf) is attached to the optical head (He), which increases the weight. ) Has a drawback in that the time required to move the target track to a desired track of the optical recording medium, that is, the so-called access time, becomes long.

Therefore, in recent years, an optical recording apparatus that performs focus control using an air flow accompanying rotation of an optical recording medium has been developed.

That is, this type of optical recording apparatus is shown in FIGS.
As shown in the figure, a movable body (k) guided by a guide member (j) and moved in the track direction by energizing a track control drive coil (mt), and a movable body (k). An optical head (He) attached via a spiral spring (n) constitutes a main part of the optical head (He). The optical head (H) utilizes an air flow accompanying rotation of the optical recording medium (d).
Because of the configuration in which e) is floated, the distance between the optical recording medium (d) and the optical head (He) is maintained substantially constant regardless of the surface deflection of the optical recording medium (d), so that a focusing error is less likely to occur. And the optical head (H
Since the focus control drive coil (mf) does not need to be attached to e), the optical head (He) becomes lighter, and as a result, the access time can be shortened.

[Problems to be solved by the invention]

However, in this type of optical recording apparatus, the optical recording medium (d) incorporated therein is configured to rotate at a constant speed, and the optical recording medium (d) has its outer periphery and inner periphery that rotate at a constant speed. Since a difference occurs in the peripheral speed, the floating force acting on the optical head (He) fluctuates between the outer peripheral side and the inner peripheral side of the optical recording medium (d) as shown in FIGS. There was a problem that easily occurred.

FIG. 18 is a graph showing the relationship between the peripheral speed (m / s) of the optical recording medium (d) and the floating amount (μm) of the optical head (He). This was obtained for the optical head shown in FIG. 14, and the spring load of the spiral spring (n) was 9.5 g, and the width dimension of the slider surface (s) on which the floating force acted was 2.1 mm × 2 = 4.2 mm. ｝ Indicates that the floating amount of the optical head (He) decreases as the peripheral speed decreases toward the inner peripheral side.

Therefore, even in an optical head (He) utilizing an air flow, some type of focus control means, for example, as shown in FIG. 19, provided on the optical axis between a light source (a) such as a semiconductor laser and an objective lens (g) and focusing. It is necessary to incorporate a diffusion lens (p) or the like for adjusting the convergence position of the beam by moving on the optical axis based on the error signal, and the difference in the floating amount of the optical head (He) depends on the optical recording medium (d). Since it is larger than the surface runout, a wide focus drive range is required,
There has been a problem that the moving stroke of the diffusion lens (p) becomes long and the size of the apparatus cannot be reduced.

A method of setting the rotational speed of the optical recording medium to be variable so as to keep the floating force acting on the optical head constant is conceivable. However, in this case, there is a problem that the drive control for the shift becomes extremely complicated. there were.

[Means for solving the problem]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an optical recording apparatus in which focus control accompanying surface deflection of an optical recording medium is easy.

That is, the invention according to claim 1 includes a movable member which is arranged near a rotating optical recording medium, is guided by a guide member and is operated to move in the radial direction of the optical recording medium, and an elastic supporting member is provided on the movable member. An optical head mounted on the optical recording medium and floating by an air flow accompanying rotation of the optical recording medium and converging a beam from a light source to a converging surface of the optical recording medium. Has a gradient angle determined according to the difference between the floating amount of the optical head on the inner circumference side and the outer circumference side of the optical recording medium, and the distance between the optical recording medium surface and the inner circumference is The present invention is characterized in that a gradient is provided that continuously narrows toward the side.

In such technical means, the gradient provided on the guide member is appropriately set to a gradient value in consideration of the configuration of an optical recording device in which the guide member is incorporated. That is, the floating amount of the optical head is determined by the rotational speed of the optical recording medium incorporated in the apparatus, the spring load of the elastic support member holding the optical head, the shape and size of the slider surface forming a part of the optical head, and the like. Since the floating amount of the optical head and the difference between the floating amount of the optical head on the inner circumference side and the floating amount of the optical head on the outer circumference side of the optical recording medium differ for each device, the difference in the floating amount can be adjusted based on these data. The inclination angle of the guide member is set to an appropriate value within a suitable range.

Here, a general method of obtaining the gradient angle will be described as follows.

First, the optical recording medium is incorporated into an optical recording device and rotated, and the floating amount of the optical head in the device (μm)
The relationship between the speed and the peripheral speed (m / s) was measured to create a graph as shown in FIG.
Ask for.

Y = k × v (where Y is the floating amount (μm) and v is the peripheral speed (m / s)) Next, the outermost and innermost areas of the recording layer of the optical recording medium in the optical recording apparatus Is obtained, and this value is substituted into the above equation to determine the floating amount Y of the optical head at each part.

 That is, the peripheral speed v1 (m / s) in the outermost region is: v1 = 2 × π × r1 × z / 60 × 1/1000 (m / s) Y1 = k × v1 = k × 2 × π × r1 × z / 60 × 1/1000 (m / s) The peripheral speed v0 (m / s) in the innermost region is: v0 = 2 × π × r0 × z / 60 × 1/1000 (m / s) Y0 = k × v0 = k × 2 × π × r0 × z / 60 × 1/1000 (μm)

Here, z is the rotation speed (rpm) of the optical recording medium, r1 is the diameter value (mm) of the outermost area as shown in FIG. 12 (A), and r0 is the diameter value (mm) of the innermost area. Is shown.

Then, a difference (Y1-Y0) between the floating amounts is obtained, and a gradient angle (θ) of the guide member corresponding to the difference is obtained.

That is, Y1−Y0 = k × 2 × π × r1 × z / 60 × 1 / 1000−k × 2 × π × r0 × z / 60 × 1/1000 = k × 2 × π × z / 60 × 1 / 1000 × (r1−r0) θ = tan ⁻¹ (Y1−Y0) / (r1−r0) = tan ⁻¹ (k × 2 × π × z / 60 × 1/1000) A gradient is formed on the guide member. As a means for performing this, the guide member situation may be provided to be inclined with respect to the optical recording medium, or the guide member may be provided with a gradient by inclining a fixed base that supports the entire member such as the guide member and the movable body. Well optional.

Also, since the difference in the floating amount of the optical head that determines the inclination angle of the guide member changes according to the set rotation speed of the optical recording medium, the inclination angle can be changed according to the set rotation speed of the optical recording medium. May be formed.

In this case, the means for providing the guide member with a gradient is arbitrary as described above.

Next, regarding the configuration of the optical head mounted on the movable body, when this technical means is applied to an optical recording device such as a "drilled type", a "valve type" or a "phase change type",
The main part is composed of a floating body that floats by the air flow accompanying the rotation of the optical recording medium, and an objective lens that is attached to the opening for the optical path of the floating body and converges the beam from the light source to the converging surface of the optical recording medium. When this technical means is applied to an optical recording apparatus of the "magneto-optical recording type", the floating main body and the objective lens, and the optical system mounted near the optical path opening of the floating main body. The main part is constituted by magnetic field generating means such as a coil for forming a magnetic field toward the converging surface of the recording medium. The floating body needs to have at least a slider surface and an air introduction surface on its bottom side in order to efficiently receive the floating pressure from the optical recording medium. In order to stabilize the floating movement of the floating body, a concave groove for allowing air to escape along the length direction of the floating body, that is, a central relief portion may be formed. In this case, the number and shape of the grooves can be arbitrarily set according to the purpose.

Further, when this technical means is applied, the distance between the optical recording medium and the optical head can be kept substantially constant, so that it is not necessary to provide a diffusion lens or the like for focus control. Naturally, a method of disposing a diffusion lens composed of a convex lens, a concave lens, and the like disclosed in Japanese Patent Laid-Open No. 61-284836 and Japanese Patent Laid-Open No. 62-66428 may be used. In this case, in addition to the diffusion lens, a collimating lens for converting the beam diffused by the diffusion lens into a parallel beam may be provided on the optical axis between the diffusion lens and the objective lens.

[Action]

According to the invention of claim 1, the guide member for guiding the movable body is provided with a gradient such that the distance between the guide member and the optical recording medium surface continuously decreases from the inner peripheral side to the outer peripheral side. The difference between the floating amount of the optical head on the outer peripheral side and the floating amount of the optical head on the inner peripheral side is adjusted by the distance difference between the guide member on the outer peripheral side and the inner peripheral side on the optical recording medium surface. Can be kept substantially constant.

When the inclination angle of the guide member is formed so as to change in accordance with the set rotation speed of the optical recording medium, the optical heads on the outer circumference side and the inner circumference side of the optical recording medium are set according to the set rotation speed of the optical recording medium. Even if the floating amount difference changes,
Correspondingly, the gap difference between the guide member on the outer peripheral side and the inner peripheral side of the optical recording medium surface can be changed, and the optical recording medium and the optical head can be moved irrespective of the difference in the set rotation speed of the optical recording medium. Can be kept substantially constant.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

That is, the optical recording apparatus according to this embodiment
As shown in FIG. 9 to FIG. 9, a movable body (2) arranged near the optical disk (1), and an optical head (4) mounted on the movable body (2) via a spring material (3). And a drive section (5) for moving the movable body (2) in the track direction of the optical disk (1), and its main part is constituted.

First, the movable body (2) is composed of a bobbin-less drive coil (20) formed by integrally joining a wound coil with an epoxy adhesive and being formed as shown in FIGS. 2 and 4. A coil main body (22) formed into an elliptical cylindrical shape and having a substantially square opening (21) on the side surface facing the optical disk (1), and an opening (2) in the coil main body (22).
1) The inner wall (2) of the coil body (22)
3) and a pair of reinforcing coil walls (25) forming an insertion portion (24), and on the inner wall surface facing the opening (21) in the coil body (22). Is provided with a mirror (26) for introducing a laser beam from a light source (not shown) to the optical disk (1) side.

On the other hand, the optical head (4) floats by an air flow accompanying rotation of the optical disk (1) and has an alumina opening provided with an optical path opening (40) for introducing a laser beam from a light source toward the optical disk (1). A floating body (41) made of ceramics, and a laser beam from a light source attached to an optical path opening (40) of the floating body (41) and an optical disk (1)
Plastic objective lens (4
2) and a taper (43) (4) at the air inflow end and the air outflow end of the surface of the floating body (41) facing the optical disc (1) to smoothly inflow and outflow of air.
4), a central relief portion (46) for stabilizing the floating traveling of the optical head (4) is provided substantially at the center of the slider surface (45), and as shown in FIG. It is attached to the opening (21) of the movable body (2) via a spring material (3) made of phosphor bronze as shown.

The drive section (5) includes an aluminum carriage (50) attached to the bottom surface of the movable body (2).
A linear bearing (51) into which the carriage (50) is fitted to guide the movable body (2) in the track direction of the optical disk (1); and an optical disk (1) inserted through the insertion portion (24) of the movable body (2). ), A pair of pure iron magnetic yokes (53) and (53) disposed along the track direction, and a rare earth iron-based permanent magnet disposed along the length direction of these magnetic yokes (53) and (53). Arc-shaped magnets (54) and (54) formed by the above, a pure iron magnetic holder (55) holding these magnets (54) and (54), the carriage (50), and the linear bearing (51) The main part is constituted by a magnetic fixing table (56) made of pure iron which supports the entire member such as the above. The magnetic fixing table (56) as shown in FIGS. ) To the slope angle (θ)
Is provided, so that the distance between the linear bearing (51) corresponding to the guide member and the surface of the optical disk (1) continuously decreases from the inner peripheral side to the outer peripheral side of the optical disk (1). (In this case, the gap difference between the inner peripheral side and the outer peripheral side is adjusted to about 1.9 μm). A hard thin film of chromium metal or the like is formed on the contact surface side of the carriage (50) with the linear bearing (51) to improve durability, and a bearing (57) is fitted to reduce frictional force. Is embedded.

In the optical recording apparatus thus configured, the movable body (2) moves in the track direction of the optical disc (1) by the electromagnetic force accompanying the energization of the driving coil (20), as in the conventional apparatus. Accordingly, the optical head (4) is also moved to perform track control, while focus control is performed using the floating phenomenon of the optical head (4).

Here, the optical disk (1) incorporated in the optical recording apparatus is rotated at a rotation speed of 1800 rpm, and the outermost area of the recording apparatus has a diameter of 120 m.
m, while its innermost region corresponds to a region with a diameter of 60 mm.

 The peripheral speed of each part is the outermost region, and v1 = 2 × π × 120/2 × 1800/60 = 2 × 3.14 × 60 × 30 = 11.304 × 1000 (mm / s) = 11.3 (m / s) In the innermost area, v0 = 2 × π × 60/2 × 1800/60 = 2 × 3.14 × 30 × 30 = 5.652 × 1000 (mm / s) = 5.7 (m / s).

Therefore, when the floating amount of the optical head (4) at each part is obtained from the graph of FIG.
m, about 2 μm in the innermost region, the difference is 1.9 μm, which causes a focus error.

However, in this optical recording device, a gradient of the gradient angle (θ) is provided on the magnetic fixed base (56) constituting a part of the drive section (5), and the gradient corresponds to a guide member. The distance between the linear bearing (51) and the surface of the optical disk (1) is continuously narrowed from the inner peripheral side to the outer peripheral side of the optical disk (1), and the distance between the inner and outer peripheral sides is about 1.9 μm. Has been adjusted.

Therefore, the difference (approximately 1.9 μm) in the floating amount of the optical head (4) between the outer peripheral side and the inner peripheral side of the optical disk (1) is equal to the linear bearing (51) on the outer peripheral side and the inner peripheral side of the optical disk (1).
Because it is adjusted by the gap difference (approximately 1.9 μm)
As shown in FIGS. 9 to 12, the distance between the optical disk (1) surface and the optical head (4) can be kept substantially constant, which has the advantage of not causing a focus error.

The data shown in the graph of FIG. 18 relates to a conventional apparatus in which the magnetic fixed base (56) is not provided with a gradient as described above, and the magnetic fixed base (56) is provided with a gradient. The floating condition applied to the optical head (4) is slightly different from that of the optical recording apparatus according to the embodiment. However, under a gradient condition in which the distance between the outer circumference and the inner circumference of the optical disc (1) is only about 1.9 μm, the difference between the floating conditions was almost negligible.

Although this optical recording apparatus does not include a diffusion lens or the like for focus control, it goes without saying that the present invention may be applied to an apparatus having a diffusion lens or the like. In this case, since the movement stroke of the diffusion lens or the like becomes extremely small, there is an advantage that the size of the apparatus can be reduced.

Further, in the optical recording apparatus according to this embodiment,
The magnetic fixed table (56) is provided with a gradient, and the linear bearing (51) corresponding to the guide member is inclined by the gradient. Instead of providing the magnetic fixed table (56) with a gradient, the linear bearing (51) is used. It goes without saying that a configuration in which the same gradient is provided for itself may be used.

Further, as shown in FIG. 10, an optical device having a driving portion (7) for driving and guiding a spring-like suspension (6) having an optical head (4) attached to one end thereof at a gradient angle (θ). Naturally, the present invention can be applied to a recording device.

[Effect of the invention]

According to the first aspect of the present invention, the difference between the floating amount of the optical head on the outer peripheral side and the inner peripheral side of the optical recording medium is adjusted by the distance difference between the guide members on the outer peripheral side and the inner peripheral side of the optical recording medium surface. Therefore, the distance between the optical recording medium and the optical head can be kept substantially constant.

Therefore, it is not always necessary to provide a diffusion lens or the like for focus control, which has the effect of simplifying focus control. In addition, when the diffusion lens or the like is incorporated, the movement stroke can be extremely reduced. This has the effect that the size can be reduced.

[Brief description of the drawings]

1 to 10 show an embodiment of the present invention. FIG. 1 is a schematic partial perspective view of an optical recording apparatus according to the embodiment, and FIG.
The figure is a sectional view taken along the line II-II in FIG. 1, and the figure 3 is a III-III in FIG.
FIG. 4 is a schematic partial perspective view of an optical recording apparatus in which an optical head and a spring material are omitted in FIG. 1, and FIG. 5 is a perspective view of a carriage and a linear bearing which are constituent members of the apparatus. , FIG. 6 is a plan view of a spring material applied in the embodiment, FIG. 7 is a schematic overall perspective view of an optical recording apparatus according to the embodiment, and FIG. 8 is a simplified sectional view taken along the line VIII-VIII in FIG. 9 is a partially enlarged view of FIG. 8, FIG. 10 is a schematic partial overall view of an optical recording apparatus according to a modification, and FIGS. 11 to 19 show a conventional example. FIG. 11 is an explanatory view of a configuration of a conventional optical recording apparatus, FIG. 12 (A) is a perspective view of an incorporated optical recording medium, and FIG. 12 (B) is a view B of FIG. 12 (A). FIG. 13 is a partial perspective view of a conventional optical recording apparatus, FIG. 15 is a cross-sectional view of the XV-XV plane of FIG. 14, and FIG. Kouki Illustrates the relationship between the medium, FIG. 17 is a partially enlarged view of FIG. 16, FIG. 18 a peripheral speed (m / s) and floating amount of the optical head of an optical recording medium (mu
FIG. 19 is a graph showing the relationship with m), and FIG. 19 is a diagram illustrating the configuration of a conventional optical recording device incorporating a diffusion lens. [Description of Symbols] (1) Optical disk (2) Movable body (3) Spring material (4) Optical head (5) Drive unit (51) Linear bearing

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kaoru Yasukawa 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd.Ebina Office (72) Inventor Daisuke Iguchi 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Corporation In-house (56) References JP-A-1-307030 (JP, A) JP-A-2-94115 (JP, A) JP-A-1-151025 (JP, A) JP-A-1-227232 (JP, A) JP-A-64-62836 (JP, A) JP-A-61-160844 (JP, A) JP-A-2-11516 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A movable body which is arranged near a rotating optical recording medium and is guided by a guide member to be moved in a radial direction of the optical recording medium, and is mounted on the movable body via an elastic support member. An optical recording device comprising: an optical head that floats by an air flow accompanying rotation of the optical recording medium and converges a beam from a light source to a converging surface of the optical recording medium. It has a gradient angle determined according to the difference between the floating amount of the optical head on the inner circumference side and the outer circumference side, and the interval with the optical recording medium surface is continuously changed from the inner circumference side to the outer circumference side. An optical recording device having a narrowing gradient.