JPS5914149A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a pickup having high resistance to environment and a low level in noise, by using a light transmissive cover to seal up the outlet of a focus actuator. CONSTITUTION:A transparent cover 31 made of a light transmissive glass, plastic, etc. is attached to a case 25 of an actuator to seal up the inside of a pickup device. Thus the sounds generated inside the pickup device are shut off, and at the same time the mixture of dust or waterdrops into the device. This improves the resistance to environment and reduces the level in noise for a pickup.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to dustproof and soundproof measures for a pickup device of an optical high information recording/reproducing device.

As a pick-up device for Kaede, the one shown in Figure 1 (shown here is rare.
) is a collimating lens, (3) is a diffraction grating, (4) is a polarizing beam sublime, (5) is a quarter-wave plate, (6)
is a rotating mirror, (7) is an objective lens, (8) is a recording disk, (9) is a convex lens, QO is a cylindrical lens, and Qυ is a light detector.

Next, the operation will be explained.

As is well known, for example, a semiconductor laser (1
) is provided, and this semiconductor laser (1) defines the starting point of the path of light emitted therefrom. Half 4 body laser (1)
A lens section consisting of a collimating lens (2) is first provided on the optical path from the semiconductor laser (1), and the light from the semiconductor laser (1) is made into parallel light by the collimating lens (2). From now on r@
In the previous issue, a diffraction grating (3) was installed to separate the parallel light coming from the collimating lens (2) into three beams.

The three beams pass through a polarizing beam splitter (4), a quarter-wave plate (5), are reflected by a rotating mirror (6), pass through an objective lens (7), and are directed to a recording disk (8). leading to. The beam passing through the objective lens (7) forms three focal spots on the recording disk (8) surface t.

Although not shown, the surface t of the recording disk (8) has rough irregularities called bits, and information is recorded in the form of bits. The recording disk (8) is rotating at a high speed, so that the light irradiated onto the recording disk (8) is reflected by intensity modulation depending on the presence or absence of bits and re-enters the objective lens.

The beam reflected by the recording disk (8) passes through the objective lens (7), is reflected by the rotating mirror (6), and returns along the optical path via the quarter-wave plate (5). The beam is reflected by the polarizing beam splitter (4), changed direction 90', passes through the convex lens (9) and the circumferential lens GO in sequence, and reaches the photodetector 0υ. This photodetector Q is a six-divided photodetector that has a sensitive area group divided into four in the center, and two sensitive areas sandwiched between it.

The eight beams reflected by the recording disk (8) are incident on the sensitive area group (2) and the sensitive areas I and (2), respectively. More specifically, the reflected beam corresponding to the center spot of the B condensed spots on the surface of the recording disk (8) enters the sensitive area 81, and is converted into an RF (ordinarily audio frequency) signal. A/F (A
Auto Focusing) signal is obtained. RF
The double signal is a signal representing information recorded on the recording disk (8), and the A/F signal is a signal representing information recorded on the recording disk (8).
), the focused spot is on the disk (8) surface t.
In order to avoid defocusing, the objective lens (7
) is used to control a focus actuator (not shown) that moves the lens L downward. In addition, the remaining two of the eight focused spots on the surface t of the recording disk (8) are incident on the sensitive areas (2) and 3, respectively, and the A/T (Au .

Tracking) signal is obtained. This A/T signal moves the focused spot in the radial direction of the recording disk (8) so that the focused spot always follows the track of the recording disk (8) h with respect to the eccentricity of the recording disk (8). It is used to control the rotating mirror (6).

Here, as an example of the focus actuator, the second
The figure shows a cross-sectional view of the sliding focus actuator. In the figure, eυ, ■ is the yoke material, @ is the magnet,
■ is the coil and coil holter 1) is the actuator case, (a) is the pace of the pickup device housing, and (b) is the gap between the case and the covered part @ body te, hl L, and nozzle. @(The entire actuator is shown.

The objective lens (7) is inserted into the yoke material eυ and is configured to be able to slide in the optical axis direction. The inside of υ is coated with Teflon or the like to reduce jl so that the objective lens (7) can move smoothly. In addition, the objective lens (7) is glued to the coil and the small coil holder ■, and according to the change in mtk flowing through the coil, the coil and the coil holder ~ (c) are the yoke material 3υ, ■
It is drawn into the magnetic circuit formed by the magnet 4,
be pushed out.

That is, the objective lens (7) is controlled in the downward direction t by flowing the m flow corresponding to the surface wobbling of the disk (8).

In conventional pickup devices, there was a gap (b) at the tip of the actuator, which caused dust to enter the surface of the optical components inside the pickup device and the sliding parts of the actuator, deteriorating the light focusing characteristics and impeding the regeneration function of the pickup device. The disadvantage was that the performance decreased or stopped.

In addition, the operating sound of the actuator may be heard in the gap @ or the lens (7).
) is also rarely transmitted directly from the tip.

Furthermore, there was also the problem that moisture entered through the gaps, making the surface of the optical components inside the pickup extremely thin and rendering it inoperable. This was done in order to eliminate the drawbacks of conventional ones, such as by covering and sealing the exit of the focus actuator with a transparent material such as glass or plastic that allows laser light to pass through, thereby preventing dust and dirt from forming on the surface of the optical components inside the pickup device. The purpose is to prevent moisture from entering, prevent leakage from gaps before operation, and direct sound transmission from the tip of the lens, and obtain a pick-up that is environmentally friendly and has low noise. .

An embodiment of this invention will be described below with reference to the drawings. 8th
In the figure, C3υ is a transparent lid for dustproofing and soundproofing. This transparent lid 6υ is made using normal transparent optics of 0.1 to 0.5 mm.

In the figure, a transparent lid 0υ is attached to the case of the 7-cut unit, sealing the inside of the pickup device. But-
), the sound emitted from inside the pickup device is blocked and direct transmission of sound from the tip of the lens is also prevented.

Further, the place where small dust, water droplets, etc. may adhere is limited to the dust-proof and sound-proof transparent lid 6, and there is no chance of damage to the optical components inside the pickup device.

Note that the transparent lid 0υ must be set at a position where it will not collide with the force generated by the vertical movement of the objective lens (7) or the vibration of the disk, but the position between the tip of the lens and the lens side of the disk must be set. The distance between the surfaces (working distance) is usually 2 mm, so it is quite possible.

In the example described above, the transparent lid 6υ was attached to the actuator case, but it was designed so that it could be completely covered over the actuator, and the base (7) of the pickup device twh
You can also attach it to Furthermore, the actuator case (c) and the transparent lid (v) may be integrated.

The first four diagrams show the second U of Saral et al.

The figure shows the essential parts of the entire pickup including the actuator section shown in Figure 2 and Factor 8. As described in 6a, since the lens portion is shielded by the transparent lid Gelυ, moisture does not enter into the pickup casing (6). However, if the temperature of the swirl decreases, the vapor pressure of the internal air will drop, which may cause wire connections in optical components. In the figure, - indicates a moisture absorbent housed in a breathable partition wall. This completely prevents dew condensation inside the pickup.

Of course, the same effect can be achieved by filling the inside of the pickup with dry air or N2 gas.

In addition, in the embodiment described above, a slide type actuator without a spring was used as the actuator, but
It may be a spring-type actuator. In addition, the same effect is obtained not only for pickups for playback, but also for pickups for six-ball pickups used in writable disk devices, and pickups for recording and playback. Furthermore, as for the transmission characteristics of the transparent lid, the light from the growth of optical fibers is not absorbed, and the light of other wavelengths is reflected or absorbed. This means that even if the outside light is strong, no light will enter the inside of the light source, so the light will be stronger than that in broad daylight.

As described above, according to this invention, the actuator of the pickup device is made of a transparent material such as glass or plastic that does not affect the playback function.
Since the cover is configured to be closed, it is possible to simplify the problem of uncontaminated fabric that degrades the performance of the pickup device, which has the effect of increasing the reliability and lifespan of the device. It also has the effect of reducing i-sound generated inside the pickup device.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a conventional pickup device, Fig. 2 is a sectional view showing a sliding focus actuator,
FIG. 8 is a diagram showing the structure of a sliding focus actuator with a dustproof and soundproof lid according to one embodiment of the present invention, and FIG. 41A is a diagram showing the structure of a moisture-proof pickup according to another embodiment 1 of the present invention. It is a diagram. (In the figure, (1) is the semiconductor laser, (7) is the objective lens, (8) is the d-axis disk, - is the actuator, and c
Iυ is a transparent lid. In the figures, the same reference numerals indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 1 Figure 2 Figure 3 Figure 4 31'/

Claims (1)

[Claims] A photonic lens for irradiating a recording carrier with laser light emitted from a tlJ laser source to form a light spot;
The information recording and reproducing device is equipped with an actuator that moves this optical lens for focusing and track tracking, and is characterized by an optically transparent lid provided at the tip of the actuator. Optical #-flt reporting ball-Nyu device. (2J) The transparent liquid described in j is transparent only at the light source wavelength, and other wavelengths are reflected or absorbed and are not transparent.
The optical m-information reproducing device according to any one of claims 1 to 8, characterized in that the optical m-information reproducing device is used for hunting. (3) r-=a = Dry air or inert gas is filled in the circular part of the pickup that is closed due to food.
IPIn analogy ♀Llself sphere P) Pressure fitting. Device.