JPH02265034A - Optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce the distortion of a half mirror and to prevent deviation caused by vibration and impact by fixing a viscoelastic body on the half mirror abutting part of a leaf spring and adding pressing force to the half mirror through the viscoelastic body. CONSTITUTION:The viscoelastic bodies 30a and 30b consisting of rubber material are respectively fixed on the necessary parts of an L-shaped bend part 22a and a U-shaped bent part 22b on the leaf spring 21. By making the spring 21 abut on the half mirror 3, the pressing force of the spring 21 is added to the mirror 3 through the viscoelastic bodies 30a and 30b. Since the coefficient of friction of the viscoelastic bodies 30a and 30b is large, the deviation of the mirror 3 caused by the vibration and impact is prevented and the distortion of the mirror 3 is reduced even when the pressing force of the spring 21 is small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical component in an optical information recording/reproducing device, particularly to a holding means for a half mirror.

[Conventional technology]

3 to 8 show conventional optical information recording and reproducing devices. In FIGS. 3 to 8, 1 is a light source that emits a light beam, 2 is a diffraction grating, and 3 is a half mirror 14. A collimating lens 5 is a light beam emitted from a light source 1, which is transmitted through a diffraction grating 2, reflected by a half mirror 3, and becomes a parallel beam when transmitted through a collimating lens 4.

6 is an objective lens, 6a is a track drive device, and 6b is a focus drive device, and arrows B, B', and A respectively.
, A' direction.

Reference numeral 7 denotes a disk as an information recording carrier, which is rotated by a drive source 8 such as a motor. Reference numeral 9 denotes an information bit of the disc 7, in which information content is recorded depending on the presence or absence of a recess, the length, etc.

Ioa, 10b, and 1oc are light spots irradiated onto the disk 7, which are separated by the diffraction grating 2 and condensed by the objective lens 8.

11 is a sensor lens, and 12 is a photodetector.

13 is the reflected light from the disk 7, and the objective lens 6,
The light passes through the collimator lens 4 and the half mirror 3, is further converged by the sensor lens 11, and is focused on the photodetector 12. 14 is an actuator barrel, and 15 is an optical system body.

In FIG. 7, 16 is a holder A that holds the light source 1, and is fixed to the optical system main body 15. As shown in FIG. 1F diffraction grating 2
This is a holder B that holds the optical system body 15, and is held in the optical system main body 15 so as to be rotatable about the light beam 5. 1
8 is an elastic material interposed between holder A and holder B, 19 is a holder C that holds the sensor lens 11, and is configured to be able to slide linearly in parallel to the reflected light 13 in the directions of arrows F and F'. is held in the optical system main body 15. Reference numeral 20 denotes a 45° surface provided on the optical system main body 15, on which the nof mirror 3 is held.

In FIGS. 5 to 8, reference numeral 21 denotes a leaf spring, which forms a U-shaped bent portion 22a, L-shaped bent portions 22b, 22c, and the half mirror 3 is connected to the U-shaped bent portion 22a.

45° of the optical system main body 15 at the L-shaped bent portions 22b and 220
It is pressed and held on the surface 20.

Reference numerals 23B and 23b are positioning holes provided in the plate spring 21, which are fitted into bosses 24a and 24b on the optical system main body 15 for positioning and holding at the same time. 25 is photodetector 1
2, and is held so as to be able to slide on the flat part 26 of the optical system main body 15 in the direction of the arrow. 6th
In the figures to FIG. 8, L is the thickness of the half mirror 3.

Next, the operation will be explained. A light beam 5 emitted from a light source 1 is transmitted to a diffraction grating 2. Half mirror 3° collimating lens 4. It passes through the objective lens 6 and is irradiated onto the disk 7.
Light spots (10a, 10b, toe) are formed on the disk 7.

On the other hand, on the disk 7, information pits 9 representing information signal contents, for example, in terms of length, are sequentially arranged concentrically or spirally to form an information track.

The reflected light 13 from the top of the disk 7 rotated by the drive source 8 travels backward along the incident optical path to the top mirror 3.
The light passes through the sensor lens 11 and enters the photodetector 12, where it is converted into an electrical signal.

By processing the output signal from the photodetector 12, the information recorded on the disc 7 is reproduced.

On the other hand, based on the output signal of the photodetector 12, it is also possible to extract a shift signal of the optical spots 10a, 10b, lQc on the disk 7 in the focus direction (arrow A, A' direction).

When the disk 7 rotates, vertical vibrations in the directions of arrows A and A' and eccentric movements in the directions of arrows B and B' occur. Therefore, a focus drive device 6b is provided for the vertical vibration, and a track drive device 6a is provided for the heart-breaking motion.
This track drive device 6a not only drives the objective lens 6 in the radial direction of the disk 7 (in the directions of arrows B and B'), but also drives the optical system body 15 using a known drive source.
By driving each disk 7 in the radial direction, the deviation from the track position is corrected.

By the way, in order to perform the above information recording and reproduction with high precision, it is necessary to devise the above-mentioned optical components and optical component arrangement using known optical system design methods. There is a method to reduce the thickness L8 of -3.

As a well-known example, the optical system body 15 of 8-FUMIJI 3
As means for holding the 5° plane 20, there are a holding method using a leaf spring 21 as shown in FIGS. 5 to 8, and a holding method using an adhesive. The holding method using an agent is inappropriate because it tends to distort the half mirror 3 and deteriorate the optical performance of the light beam 5 reflected by the half mirror 3. Therefore,
A method of holding the leaf spring 21 by reducing the pressing force is used, but if the pressing force is too small, the half mirror 3 may shift in the directions of arrows H and H' in the figure due to vibrations and shocks applied to the optical system main body 15. , the reflection angle of the light beam 5 and the reflected light 1
The refraction angle during transmission of 3 changes slightly, and light detection 812
Since the photo-electric conversion characteristics in the photoelectric conversion process would deteriorate, it was necessary to pay sufficient attention to this.

[Problem to be solved by the invention]

Since the conventional optical information recording/reproducing device is configured as described above, in order to suppress the distortion of the half mirror 3, the leaf spring 21, which is a means for holding the half mirror 3 against the 45° plane 20 of the optical system main body 15, is used. The pressing force must be small, and if the friction coefficient of the contact area between the leaf spring 21 and the half mirror 3 is small, the half mirror 3 will shift when vibrations or shocks are applied, and the optical performance will deteriorate. There were problems such as: There is also a method of holding the half mirror 3 using a combination of the leaf spring 21 and an adhesive, but there is a problem in that it is difficult to control the amount of adhesive applied.

B's invention was made to solve the above problems, and it is possible to avoid distortion even when the thickness of the half mirror becomes thinner, and to prevent the half mirror from shifting due to vibrations, shocks, etc. An object of the present invention is to obtain an optical information recording/reproducing device equipped with a half mirror holding means.

[Means to solve the problem]

Optical information recording and reproducing device according to the invention of B [Yo, a viscoelastic body is fixed to the half-mirror contact portion of the plate spring, and the pressing force of the plate spring is applied to the half mirror via the viscoelastic body. This is what I did.

[Effect]

In the optical information recording/reproducing device according to the invention of B, since the viscoelastic body is fixed to the contact portion of the half mirror of the plate spring, the friction coefficient of the viscoelastic body is small even if the pressing force of the half mirror by the plate spring is small. Because it is large, it is possible to prevent the half mirror from shifting due to vibrations and shocks, and to reduce distortion to the half mirror.

〔Example〕

An embodiment of the present invention will now be described.

1 and 2, FIG. 1 is a configuration diagram showing a half mirror holding means according to the present invention, and FIG. 2 is a plan view seen from the direction of arrow E in FIG. 1.

In each figure, the same reference numerals as in FIGS. 3 to 8 indicate the same or equivalent parts, and 30a and 30b are the half mirrors 3 at the U-shaped bent portion 22a and the L-shaped bent portion 22b of the leaf spring 21, respectively.
It is a viscoelastic body with a large coefficient of friction that is integrally fixed to the abutting portion of the body, and in this embodiment, it is made of a rubber material.

As shown in FIGS. 1 and 2, the optical information recording and reproducing apparatus according to the present invention uses a plate spring (11) as a holding means for the half mirror 3 with respect to the optical system main body 15. 8-A contact portion with Fumiji 3, that is, an L-shaped bent portion 22a.

Viscoelastic bodies 30a, 30b made of rubber material are fixed to key points of the U-shaped bent portion 22b, respectively, and the viscoelastic bodies 30a, 3
The plate spring 21 and the half mirror 3 are brought into contact with each other through the 0b, and the pressing force of the plate spring 21 is controlled by the viscoelastic bodies 30a, 30.
It is applied to the half mirror 3 via b.

As a result, since the friction coefficient of the viscoelastic bodies 30a and 30b is large, even if the pressing force of the leaf spring 21 is small, the half mirror
3 can be prevented from shifting due to vibration and impact, and distortion of the half mirror 3 can be suppressed to a minimum.

In addition, in the above embodiment, the optical system main body 1 of the half mirror 3
5, a viscoelastic body 30a is placed on the plate spring 21 as a holding means for the plate spring 21.
, 30b are shown fixed, but the leaf spring 21 itself may be made of a viscoelastic material having a large coefficient of friction.

〔Effect of the invention〕

As described above, according to the present invention, in the means for holding the half mirror to the optical system main body, it is possible to suppress distortion imparted to the half mirror, and moreover, it is possible to suppress distortion caused by vibrations, shocks, etc.
It is possible to suppress misalignment of fumidji, and an inexpensive and reliable device can be obtained.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a holding means for a half mirror and an optical system main body according to the present invention, Fig. 2 is a plan view seen from the direction of arrow E in Fig. 1, and Fig. 3 is a configuration of an optical information recording/reproducing device. 4 is a sectional view showing the shape of a light spot on an information recording medium, FIG. 5 is a perspective view showing the main body of the optical system, FIG. 6 is a side view seen from the direction of arrow C in FIG. 7 is a sectional view of the center side in FIG. 6, and FIG. 8 is a configuration diagram of the sixth drawing section. In the figure, 3 is a half mirror, 15 is a light beam, 7 is a disk, 15 is a leaf spring, and 30a and 30b are viscoelastic bodies. Note that the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] In an optical information recording and reproducing device that records and reproduces information by irradiating a light beam onto an information recording carrier, a viscoelastic material is mounted on a plate spring that presses and holds a half mirror that reflects and transmits the light beam against the optical system body. Hold your body together,
An optical information recording/reproducing device characterized in that the pressing force of the leaf spring is applied to the half mirror via the viscoelastic body.