JPH0358324A - Optical head transfer device - Google Patents

Abstract

PURPOSE:To improve the efficiency of an optical head transfer device by quickening the mean seek time by performing positioning by abutting the lower plane of a cartridge which holds a disk-shaped recording medium with the upper plane of the yoke of a linear motor. CONSTITUTION:Generally, as for relation between the height of a linear motor unit 12 and the mean seek time, the more increased the height H, the more magnetic flux density at a magnetic circuit can be increased. Therefore, thrust can be increased by eliminating a gap between an upper yoke 3 and the cartridge 34 and increasing the height H of the linear motor unit 2 itself by that share, which accelerates the mean seek time. Furthermore, the frequency characteristic of the linear motor can be improved by conforming the center of gravity of a movable part to an operating point, and the thrust can be efficiently improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical head transfer device, and more specifically, the present invention relates to an optical head transfer device, and more specifically, a light beam is irradiated onto the surface of a disk-shaped recording medium (hereinafter simply referred to as a disk) to convey information. The present invention relates to an optical head transfer device for an optical information recording/reproducing device capable of recording, reproducing, or erasing information.

[Conventional technology] In recent years, with the development of electronics, optical beams have been used to randomly record audio or image information with high performance. Optical information recording and reproducing devices that can reproduce or erase information have been commercialized.

For example, in optical video equipment, an optical head detects recorded information consisting of a pattern of protrusions (pits) on a disk surface made of transparent acrylic resin, transparent polycarbonate, etc., converts it photoelectrically, and then adjusts the gain to an appropriate level using an amplifier. However, the data can be further converted into a predetermined analog value via a reproduction circuit such as a DA converter, and then outputted using an output device. By the way, the current HDD (hard drive)
For example, in the case of a 5IA inch disk size, the disk drive) is 82.5 x 146 x 203 mm.
There is a fixed volume (full height size),
Within such a fixed volume, various structural changes are made in optical discs as well.

FIG. 4 shows an example of an optical head 21 and a linear motor unit 22 for moving the optical head in such a conventional optical disk drive. The optical head 21 shown here includes everything from the laser 23 to the actuator unit 24 and further to the detection system 25, and is configured as one optical head. Because of the large size, it is not possible to arrange linear motor units on both sides (left and right), and the linear motor unit 22 is arranged only on one side. Therefore, the center of gravity of the optical head 2l cannot be used as the point of action, which is a major factor in slowing down the access time. In addition, in FIG. 4, 26 is a spindle motor unit for rotating a disk (not shown);
27 has that turntable.

On the other hand, FIG. 5 shows an example of a so-called separated optical type in which the movable part is lightened and the detection part is separated. That is, in the wooden example, members including the detection section, the laser 23, etc. are fixed as a fixed head section 28, and a carriage 29 portion on which an actuator unit (not shown) is attached is configured as a movable section. Therefore, in the case of a wooden example, an advantage of faster access time can be obtained compared to the integrated optical head 21 shown in FIG.

FIG. 6 shows a cross section taken along the line A-A in FIG. 5, in which the actuator unit 24 is mounted on the carriage 29.
& has been. 30 is a guide shaft that guides the carriage 29 mounted on the actuator unit 24, 3l is a bearing that holds the carriage 29 on the guide shaft 30, and 32 is a leaf spring that pushes up and maintains the bearing 3l from below. The left and right linear motor units 22 are respectively attached to both sides of the carriage 29 and include a motor bobbin 1 around which a coil (not shown) is wound, a center yoke 2 that penetrates the motor bobbin 1 and keeps the bobbin 1 movable, and It is composed of an upper yoke 3, a lower yoke 4, and permanent magnets 5 attached to the upper and lower yokes, respectively. Further, 6 indicates each linear motor unit 24 as shown in FIG.
This is an assembly screw to maintain the positioning between each yoke. In addition, FIG. 7 shows one linear motor unit 2.
2 as viewed from the side.

By being assembled in this manner and by arranging the near motor unit 22 on both sides of the carriage 29 holding the actuator unit 24, the carriage 29 and the actuator unit 24 can be moved along the radial direction of the optical disc 33. Note that 34 is a cartridge that houses and holds the optical disc 33.

[Problems to be Solved by the Invention] However, although the conventional information recording device equipped with a separating optical type movable part as shown in FIG. 5 is designed to quantify the movable part, As shown in FIG. 2, since the upper actuator unit 24 is heavy, the center of gravity of these movable parts is higher than the level of the point of action, which generates a vertical rotational moment that pushes up and supports the bearing 31 from below. A resonant mode occurs in the leaf spring 32 that is being held. In addition, the efficiency of the near motor decreases due to the rotational moment acting on it, slowing down the access time, and posing an obstacle to downsizing the optical disk drive in the height direction. In addition, in FIGS. 6 and 7, H indicates the net height of the linear motor unit 22 itself, and since the screw head of the assembly screw 6 protrudes, conventionally, the height is above the linear motor unit 22 itself. Approximately 2 m
A gap G of about /m was maintained.

An object of the present invention is to focus on the above-mentioned conventional problems, and in order to solve the problems, the center of gravity of the linear motor unit is raised relative to the actuator unit and the carriage, and the center of gravity of the movable part is adjusted to the effect of the linear motor. It is an object of the present invention to provide an optical head transfer device that can shorten seek time and increase efficiency by making the points coincide with each other.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a method for recording/reproducing information and/or erasing information using a light beam on a disk-shaped recording medium rotatably held in a cartridge. In order to drive a carriage equipped with an optical head capable of It is characterized in that it is brought into contact with.

[Function] According to the present invention, the uppermost surface of the yoke constituting the magnetic circuit and the lower surface of the cartridge are brought into contact with each other so as to eliminate the vertical gap between the two, so that the magnetic circuit structure element relative to the carriage is removed. By increasing the relative height of the linear motor unit, the center of gravity of the movable parts including the carriage can be aligned with the point of action of the near motor, and by increasing the height of the linear motor unit itself by the gap, the seek time can be reduced. It is possible to provide a shortened and efficient optical head transfer device.

[Examples] Examples of the present invention will be described below in detail and specifically based on the drawings.

1 and 2 show one embodiment of the invention. This example differs from the conventional example shown in FIGS. 6 and 7 in that the upper yoke 3
The gap G between the upper yoke 3 and the cartridge 34 is eliminated, and the height of the wood-glued near motor unit lz itself is increased accordingly, so that the lower surface of the cartridge 34 remains in contact with the upper yoke 3. . Therefore, in the wooden example glue near motor unit l2, its height +1A can be made approximately 2 mm higher than the example shown in Fig. 6, and therefore the center of gravity of the entire movable part is raised by that amount, so that it almost coincides with the point of action. can do.

By the way, there is generally a relationship as shown in FIG. 3 between the height H of the linear motor unit 12 and the average seek time, and the higher the height H, the higher the magnetic flux density in the magnetic circuit. As shown in the wooden example, by increasing the height HA, the thrust increases, and therefore the seek time becomes faster on average.

Furthermore, by making the center of gravity of the movable part coincide with the point of action as described above, the frequency characteristics of the linear motor are improved, and the thrust can be efficiently improved.

Note that in order to eliminate the gap G on the upper yoke 3 as in this example, it is necessary to eliminate the heads of the screws 6 for assembling the linear motor. This can be easily solved by forming a screw head such that the entire screw head is sunk from the upper surface of the upper yoke 3, or by using a countersunk screw.

Furthermore, in this embodiment, the cartridge is positioned in the vertical direction by bringing the bottom surface of the cartridge 34 into contact with the top surface of the upper yoke 3 of the beam near motor unit l2. 34
is not limited by the loading method of
Furthermore, it goes without saying that the cartridge 34 and the upper yoke 3 do not need to be in full contact with each other;
It is easier to maintain positioning accuracy in the height direction by maintaining contact within a specific range.

Furthermore, although the embodiments described above are based on the case where a head with a separation optical system is used, it goes without saying that the present invention can also be applied to a case where an integrated head as shown in FIG. 4 is used. do not have.

[Effects of the Invention] As explained above, according to the present invention, the lower surface of the cartridge holding the disk-shaped recording medium is brought into contact with the upper surface of the yoke, which is a component of the magnetic circuit of the linear motor, for positioning. , it is possible to speed up the average seek time and increase efficiency.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of the optical head transfer device of the present invention. Fig. 2 is a block diagram showing Fig. 1 viewed from the direction of the arrow. Fig. 3 Characteristics showing the relationship between the height of the beam near motor and the average seek time. 4 is a perspective view showing the configuration of a video disc device equipped with a conventional integrated optical head; FIG. 5 is a perspective view showing the configuration of a video disc device equipped with a conventional separated optical system head; 6 is a sectional view taken along the line A-A in FIG. 5, and FIG. 7 is a configuration diagram showing the relative relationship between a conventional linear motor and a cartridge. DESCRIPTION OF SYMBOLS 1... Linear motor bobbin, 2... Center yoke, 3... Upper yoke, 4... Lower yoke, 5... Magnet, 6... Assembly screw, 12... Linear motor unit, 21... Optical head, 24... Actuator unit, 29... Carriage, 33... Optical disk, 34... Cartridge.

Claims (1)

[Claims] For driving a carriage equipped with an optical head capable of recording, reproducing, and/or erasing information using a light beam on a disk-shaped recording medium rotatably held in a cartridge. , an optical head transfer device having a magnetic circuit constituted by a plurality of yokes and magnets parallel to the lower surface of the cartridge, characterized in that the lower surface of the cartridge is brought into contact with the uppermost surface of the plurality of yokes. Optical head transfer device.