JPS5835736A - Actuator for hologram lens - Google Patents

Abstract

PURPOSE:To reduce the weight of a moving part, by forming a hologram lens and a coil pattern for driving on the same board. CONSTITUTION:A hologram lens 18 is formed at a center of a board 17 made of glass and optical plastic by using bichromate gelatin, and coil patterns C1, C2 are formed with aluminum vapor-deposition to form a moving plate 20. The moving plate 20 is supported with a spring 23 so that the coil patterns C1 and C2 are located in a magnetic gap of magnetic circuits M1 and M2. Since the moving plate 20 is moved in parallel upward and downward by flowing a current to the coil patterns C1 and C2, focusing can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical disk reproducing apparatus using the IIA hologram lens.

Generally, a laser light source 1. as shown in Fig. 1 is used. Beam expander 2. Beam fritter 3. 174 wavelength plate 4. Cellar 5. Hodaram lens 6. It is in the optical system of an optical disk reproducing device using a hologram lens consisting of an optical signal detector 7, and when the disk 8 rotates, the hologram lens 6 follows the surface wobbling that occurs at tIK so that the beam is focused on the bit (2). When the focus servo is controlled, the eccentricity of the disc 8 makes one turn! It is necessary to provide various servo mechanisms such as a tracking servo that controls the beam A to follow the track deflection occurring in the radial direction P so that the beam traces an integral track.

Conventionally, as a two-dimensional actuator that performs focus servo and tracking servo of a hologram lens, as shown in FIG. A focus drive unit in the form of a near motor, consisting of a hologram, and a tracking drive IIB consisting of a magnet 13° tracking wheel 14 and springs 15 and 16 that move the hologram melodies in parallel in the left and right direction are integrated. It is used.

However, in a conventional hologram lens actuator like this, the moving part of the hologram lens 60 is heavy, which places a burden on the servo system and lowers its controllable frequency, making it difficult to focus and track with good NF:. This has the disadvantage that the reproduced signal is degraded because it cannot be performed.

The present invention has been made in consideration of the above points, and by making the movable part of the hologram lens have a special structure, it is possible to reduce the weight of the hologram lens and perform highly accurate 7-orcasing, tracking, etc. A hologram lens actuator with a simple structure is provided.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the attached documents.

Figure 3 shows an actuator for a one-dimensional hologram lens that can perform focusing.A hologram material such as dichromate gelatin is placed in the center of a rectangular substrate 17 made of glass or optical plastic. A hologram lens is formed using a hologram lens, and a pattern of a pair of coils CI and C2 in which the directions of winding are opposite to each other is formed by one continuous line by vapor deposition means such as aluminum on both sides of the hologram lens. 19 (see m4FIA) is mounted between a pair of magnetic circuits M1 and M2, each consisting of a magnet 21 and a yoke 22, via a spring n, as shown. In this case, the movable plate part and the magnetic circuit are arranged so that the optical axis B passes perpendicularly through the center of the hologram lens magazine and the coils CI and C2 are located between the gaps 11 and 11 of the respective magnetic circuits Ml and M2, respectively. Roads Ml and M2 are provided.

Therefore, in the one-dimensional actuator configured in this way, if a current of an appropriate magnitude is supplied to the coil pattern 19, the gaps gl, gj of the magnetic circuits Ml, M2 can be reduced.
A repulsive force or an attractive force in the same direction acts on each of the movable plate portions in the vertical direction along the optical axis IK. k), thereby making it possible to perform focusing.

Further, as shown in FIG. 6, a movable plate part' having a hologram lens tin formed at the center of the circular substrate 17' surface and one coil pattern 19' formed around its periphery 11 is used. The movable plate part' is a magnetic path M consisting of a substantially cylindrical slit 4' with a gap g formed opposite to a ring-shaped magnet 21' provided with a circle 11K as shown in FIG.
The structure is such that it is mounted on the 3rd circle via a spring n (the trap is arranged so that the gap flaK coil pattern 19' is aligned).

Focusing servo control can be performed in exactly the same way as in the case described above.

jl! Figure 7 shows another embodiment of the present invention, in this case a two-dimensional hologram lens that can perform servo control for servo control and tracking. - shows eta.

In other words, in this case, as shown in the line drawing 111IK, when a hologram lens is formed at the center S of the rectangular substrate 1711, one continuous line on both sides of the hologram lens can be formed alternately.
A pair of coils CI whose spring direction is opposite to /%,
The pattern 1 of C2 is formed, and a pair of independent coil patterns 25 with the same %-10,000@l are formed on both sides of the coil pattern crane, respectively, and nine movable plates 26N- are used. As shown in Figure 7, the movable plates are a pair of magnetic 111 mm 4. i
It is configured such that it is mounted on the AS connection via a spring 29.

In addition, in this case, each magnetic path M4. When the coils CI and C2 are located in the gap g3 of the l-shaped portion Y1 in M5, the movable plate and Magnetic path M4. MS is installed. In addition, especially in the relationship between each filter section Y2 and the coils C3 and C4, the pitch between the centers of each coil Y2 is smaller than the pitch 11 between the centers of each coil Y2. KWI & is set so that the pitch t2 between the centers is shorter by )t, and when no current is applied to the coils C3 and C4, the distribution is 4t/2 on both the left and right sides due to the action of spring 4. The optical axis B is set so that it passes directly through the center of the hologram lens.

Even with a two-dimensional actuator configured in this manner, focusing servo control can be performed in exactly the same way as in the case of AISA.

The tracking servo control is performed as follows. That is, when the maximum current t- is applied only to the coil C3, the action of the generated magnetic field causes the movable plate 26F! When the movable plate 26 is moved to the left by 4t/2 minutes as shown in Fig. 9(b) K, and the maximum current is applied only to the coil C4, the movable plate 26 is moved by the action of the generated magnetic field as shown in Fig. 9(c) K. It will move to the right by At/2 minutes. Therefore, coil C3 also 1Jc4 K
By adjusting the magnitude of the supplied current V, the movable plate 2
It becomes possible to carry out tracking by appropriately horizontally moving left or right within the range of It/2.

Although not shown in II#, the seventh
Needless to say, by adopting a configuration similar to that shown in the figure, tangential servo control can be easily performed.

As described above, in the actuator for a hologram lens according to the present invention, a movable plate having a coil pattern formed on the same substrate forming the hologram lens is placed in a special air circuit so that the coil pattern is located in the gap part. The movable plate is disposed via a spring and moved by the action of the magnetic field generated when current is supplied to the coil pattern, effectively reducing the weight of the movable part in the actuator and achieving high precision focusing. It has the excellent advantage that servo control such as tracking and tracking can be performed easily.

[Brief explanation of drawings]

A simplified diagram showing an example of the configuration of an optical system of a general optical disc playback device, Volume 2 B4! Figure 3 is a front view showing the actuator of the hologram lens according to Mfll, which is a part of the present invention; Figure 4 is a plan view of the movable plate in the same embodiment; Fig. 5 is a front sectional view showing another embodiment of the present invention;
The figure is a plan view of the movable plate in the same embodiment, FIG. 7 is a front sectional view showing still another embodiment of the present invention, FIG. 8 is a plan view of the movable plate in the same embodiment, and FIG. a), 佽), (c)
FIG. 6 is a diagram illustrating tracking and operating states in the same embodiment. Intestines...Hologram lens 19.19', 24.25
... Coil path J-y 20.20', 26-Movable plate 21, 21', 27... Magnet 22, 22'
, 28...York 23.29...Spring Applicant Kiyoshi Torii Figure 1 Figure 2 Figure 6

Claims (1)

[Claims] A movable plate on which a coil pattern is formed on the same substrate that forms the hologram lens is placed in a magnetic circuit via a spring so that the coil pattern is located in the gap, and the coil pattern is A hologram lens attacher whose movable plate is moved by the action of the magnetic field generated when a current is supplied.