JPS6295746A - Optical information processor - Google Patents

Abstract

PURPOSE:To attain mass-production and uniformed quality by making a casing fitted with a light source, a converging optical system, a reception optical system and an objective lens drive mechanism with a metallic plate subject to press work, and further providing a casing rib, a half blanking and a burring tap. CONSTITUTION:The casing 22 is made of a metallic plate, subject to press work and formed into a box with a bottom and the plate thickness (t) is selected as 0.5mm<t<2mm. Plural ribs 23 are provided incorporatedly to a part or all of fold parts and the half blanking 24 is provided to the bottom or side face. The slot of the half blanking 24 has a size having a minute clearance to the width and length of the optical component constituting the converging optical system and the reception optical system and used as a positioning stopper in fitting the optical components. Further, at least one burring tap 25 for mount is provided projectingly inward to the side face of the casing 22 and uniform casings 22 by press work are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical information processing device used for reading or writing audio, video signals, etc. from an optical information recording medium.

[Background Art and its Problems] Conventionally, an optical information processing device is configured as shown in FIGS. 7 to 10, with FIG. 7 showing the optical system and FIGS. 8 and 9 showing the internal structure. , FIG. 10 shows the casing taken out.

That is, the emitted light from the light source 10 made of a semiconductor radar is separated into three beams by the diffraction grating 11, passes through the polarizing beam splitter 12, and becomes a parallel beam by the collimating lens 13. This light beam is bent at a right angle by a prism-shaped mirror 14, passes through a quarter-wave plate 15 (omitted in FIG. 7), and enters an objective lens 16. A minute spot (about 1.6 μm in diameter) is formed on the top. This light spot is reflected and diffracted by the bit of the optical disk 17, and is reflected by the objective lens 16.1.
/4 wavelength plate 15, prism mirror 14, collimating lens, e13f return beam, polarized beam splitter 12, and after passing through astigmatism lens 18, a spot (diameter of approx. 100 to 150 μm) is formed, and an audio or video signal is generated by an electric circuit system (not shown) using a photoelectric conversion electric signal, and a focus error signal for causing the convergent light from the objective lens 16 to follow the information recording row (pit). and a tracking error signal are obtained. Each error signal is power amplified, and the objective lens 1
6 is added to the drive IIh mechanism, that is, the actuator 20, and the servo? system? configuration, and can obtain stable tracking performance. In this example, the actuator 20 is of the shaft sliding rotation mechanism type, and uses electromagnetic force generated between a moving coil and a static magnetic field generated by a permanent magnet to perform focusing and tracking. Since there is no such thing, I will omit the details.

Incidentally, the optical components and actuator 20 from the light source 10 to the photodetector 19 are each fixed to a casing 21 shown in FIG. 10 by adhesive, screws, or a holding plate.

In this type of optical information processing device, the casing 21 is a mount base for optical components, especially the actuator 20.
Since the permissible value of the angle of inclination of the light beam entering the objective lens 16 attached to the objective lens 16 with respect to the optical axis is small (approximately 20 minutes or less), the actuator 20 of the reflected light beam from the prism-shaped mirror 13 should be mounted perpendicularly to the surface. It is necessary to do this within a few minutes. To this end, the optical component mounting surface of the casing 21 must be parallel to the center of the imaginary optical axis, free from undulations, and free from warping and distortion even with temperature changes (-30 to +80°C). It is necessary to have a difficult structure.

Currently, this is achieved by die-casting with aluminum alloy, cutting with a machining center, or a special machine.

However, as shown in FIG.
Since it is not possible to machine one chuck on a surface, it is not easy to reduce the number of man-hours. In addition, such a structure prevents astigmatism, especially when adjusting the photodetector 19 and the astigmatism lens 18 (the photodetector 19 has two axes of X and Y, and the astigmatism lens 18 has two axes). The inner diameter clearance and surface roughness of the lens insertion hole are advantageous for adjustment time, and the clearance is 20μ.
If it becomes more than m, adjustment becomes virtually impossible. The machining accuracy is at the level of several micrometers, and the management aspects such as wear management of cutting and galling tools and product inspection are also major factors that affect cost and cost.

Furthermore, as is usual with Guicasting, as the number of castings increases, the source of aluminum deteriorates.
The incidence of cho is higher. For this reason, when the cutter comes into contact with the cutting part during cutting, there will be some interrupted cutting.
If the ants are large, part of the component mounting reference surface may be missing, which may cause a decrease in product yield.

For the reasons mentioned above, it is difficult to reduce the product price while maintaining the product performance.

In order to solve this problem, attempts have been made to manufacture the casing 21 using engineering glass, but as it is necessary to confirm long-term reliability including resistance to temperature changes and humidity, currently only a portion of the component holder is manufactured. Recruitment has stopped at a limited level. In particular, tapping and planarity are difficult to achieve with engineering plastics.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical information processing device that can be mass-produced, has uniform quality, and can be manufactured at a low cost.

[Summary of the invention]

This invention is an optical information processing device in which a casing for mounting and fixing a light source, a converging optical system, a light receiving optical system, an objective lens driving mechanism, etc. is made of a metal plate by a press working method, and the casing is further provided with ribs. , half blanking, burring tap, etc.

[Embodiments of the invention]

In order to achieve the above object, this invention improves the casing, and only the vicinity of the casing will be explained.

That is, the optical information processing device of the present invention is configured as shown in FIG. Light source 1 for irradiating a light beam onto the optical disc 17
0, a convergent optical system including at least an objective lens 16, a diffraction grating 11, a polarizing beam splitter 12, a collimating lens 13, a prism mirror 14, and at least the objective lens 16 that receives the reflected light beam from the optical disk 17. Detector 19'f, including a light receiving optical system, and at least the objective lens 16? An objective lens drive mechanism claw actuator 20 for holding the original disk 17 in a predetermined positional relationship is fixedly attached to the casing 22.

This casing 22 is constructed as shown in Fig. 2, and is formed into a bottomed box shape using a metal plate by press working, and the plate thickness t is set in the range of 0.5≦t≦2m. There is. Also, this casing 22 has multiple glues on some or all of the bent parts! 23 is integrally provided, and the height H of this rib 23 is set in the range of 2t to 5t, and the width W is set in the range of 2t to 8t. Further, a half blanking 24 is provided on the bottom or side surface of this casing 22, and the groove of this half blanking 24 is minute compared to the width or length of the optical components constituting the converging optical system and the light receiving optical system. It is set to a width and length with a clearance, and is used as a positioning stopper when fixing optical components. or,
On the side surface of the casing 22, at least one burring tap 25 for attachment is provided so as to protrude inward.

Now, as mentioned above, a metal plate is used as the material for the casing 22, and examples of the metal plate include Al alloy plate, brass plate, stainless steel plate, mild steel plate, zinc steel plate, nickel silver plate, and titanium alloy plate. Although these metal plates can be applied, they must be selected in consideration of the shape of the device (small size, thinness), space for mounting parts, material price, press workability, post-processing, etc. It is.

The practical range is 25 kg in rolling direction tensile strength.
/m or more, copper plate is better in terms of material price, and aluminum in terms of workability.
Alloy plates, mild steel plates, etc. are good. When considering post-treatment, austenitic stainless steel sheets are most suitable, followed by galvanized steel sheets (
SPG) Derurou.

When configuring the casing 22 from these rolled materials, considering the natural frequency (FO) of the casing 22 and the use of the optical information processing device, there is no particular problem, especially in static conditioning for home use. However, if it is used as a portable or in-vehicle device. It is estimated that it is necessary to set the frequency to ≥200Hz (Nikkei Mechanical 1985.4.8.p, p65
-69). As a result, the casing 22 (N construction)
Although it depends on the parameter, the minimum practical plate thickness is 0.5
m, and the thicker one has a limit of about 2fi depending on the press accuracy (springback, amount of burrs, size of sag, warping, bending, hole spacing, etc.).

In addition, in order to keep the squareness of the four sides of the casing 22 within ±0.2°, the press tool is made with springback in mind, but the rib structure also allows for high-precision squareness. I can't do it.

[Modified example of the invention]

Figures 3 to 5 show modified examples of this invention.
The same effects as in the above embodiment can be obtained.

That is, in the case of FIG. 3, the reinforcing material 26 made of Al, for example.
() It is attached to the A, B, and 0 faces of the casing 22 by screwing, welding, or adhesive to join some of the four corners of the casing 22 and strengthen the rigidity of the casing 22.

In addition, FIG. 4 shows a reinforcing material 27 that also serves as a bearing part,
The reinforcing member 26'ff is attached to the B and 0 faces of 2 by screwing, welding, or adhesive to join a part of the 2 corners of the casing 22.

is used in combination to further strengthen the rigidity of the casing 22.

Also, FIG. 5 shows four corner parts 22a, 2 of the casing 22.
2b, 22e, 22d' (joined by drawing 9 processing,
It has improved rigidity.

〔Effect of the invention〕

The optical information processing device of the present invention includes a light source, a converging optical system,
A casing 22 for mounting and fixing a light receiving optical system, an objective lens drive mechanism, etc. is made of a metal plate due to its press workability, and is further provided with ribs 23, half blankings 24, and burring taps 25. As a result, the following excellent effects can be obtained.

(1) Material costs have been significantly reduced to about one-tenth of conventional costs.

(2) Processing costs have been significantly reduced to about one-twentieth of conventional costs.

(3) Assembly man-hours were also significantly reduced.

(4) Automatic assembly is now possible.

The effects of (1) to (3) above are approximately 5.5% in total compared to the conventional method.
The cost can be reduced to one-ninth, and this effect is extremely large. In addition, the above (4) has a great effect of accelerating the introduction of Roget in the future, making it possible to mass-produce it, and providing a stable supply with uniform quality and low prices.

More specifically, since the ribs 23t are provided, the four sides of the casing 22 can be bent at right angles with high precision. This effect further improves the rigidity of the housing and contributes to increasing the natural frequency. rib 2
If the height jH and width W of No. 3 are about twice the plate thickness t, the effect will be small and hardly expected. Moreover, if the height Hi5 is increased above, the flatness of the surface (B surface) for mounting a photodetector and the surface (A surface) for semiconductor mounting will deteriorate (approximately 5/10
0 wx), which is undesirable as it causes problems during assembly and adjustment. The width W is related to the space with the internally mounted parts, and in the current situation where there is a strong demand for miniaturization, a width of 8 is the limit.

Furthermore, it is useful to provide a half blanking 24 on a part of the bottom or side surface of the casing 22. This effect helps improve rigidity, but when a vertical force is applied to the bottom surface, which tends to crease due to the stress generated when bending, it dents and retains its state, but vice versa. When side force is applied, it returns to its original state. When this phenomenon is used to adhesively fix optical components such as prism-shaped mirrors and beam splitters to the bottom of the casing 22, the direction of the optical axis changes, which not only causes a problem, but also causes adhesive peeling, which can be fatal. with damage. In order to absorb the stress of this extended bottom surface, the above-mentioned no.
By providing 7-planking with 24-karat gold, it was possible to maintain flatness against external force distortion.

Furthermore, by using the convex part of this half blanking 24 as a positioning guide for the full predum mirror 7 and beam splitter 8, and as a slide guide for the collimating lens 9, actuator 5, etc., no special assembly jig is required.
This was highly effective in reducing assembly man-hours.

Improving the rigidity of the casing 22 is important for stabilizing the focusing and tracking performance of optical information processing devices, but is it particularly important to improve resistance to external disturbances (shocks)? In order to strengthen the 4 folds of the casing 22,
It is effective to firmly join a portion of the corner. Figure 6 shows the following three types of casings (
Finite element method (NA) when considering a), (b), and (c)
The results of studying the stiffness ratio in a computer simulation using STRAN are shown below.

The type of casing is A: 4 side bent state (approximately Fig. 2)...Dense processing only B: 4 side corner portion (approximately Fig. 3)...After dance processing,
Welding C: Joining reinforcing material to sides A and B (approximately Fig. 4) This model was made using 0.8m and 1.0mm mild steel plates.

In this case, assuming type (A) to be 1, the inherent 5PjIh number is calculated to be 209 Hz and actually measured to 230 Hz, and it can be seen that the rigidity is improved by 5 times and 7.4 times for types (B) and (C), respectively. Also, when the thickness of the casing is increased by 1.25 times, when the thickness of type (A) is increased to t, and when the thickness is increased to 7 paces, each becomes 1.
．． The rigidity can be improved by 5 times, 7.5 times, and 10.8 times. Therefore, it is considered that it can withstand use even as a vehicle.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an optical information processing device according to an embodiment of the present invention, FIG. 2 is a perspective view showing a casing used in the optical information processing device of the present invention, and FIGS. 3 to 5 are A perspective view showing a modification of this invention, FIG. 6 is a characteristic curve diagram showing the analysis results of the stiffness ratio when three types of plate thickness of the casing are used as parameters, and FIG. 7 is a general optical information processing device. Schematic configuration diagram showing the optical system of FIGS. 8 and 9
The figure shows a plan view and a cross-sectional view of a conventional optical information processing device.
FIG. 10 is a perspective view showing a casing in a conventional optical information processing device. 10... Light source, 11... Diffraction grating, 12... Polarizing beam splitter, 13... Collimating lens, 14
...Prism mirror, 16...Objective lens, 17
... Optical disc, 18... Astigmatism lenses, 19.
...Photodetector, 20...Actuator, 22...
Casing, 23...Rib, 24...Half blanking, 25...Burning tap, 26...Reinforcement material, 27...Reinforcement material that also serves as the bearing part.

Claims (10)

[Claims] (1) A light source for irradiating a light beam onto an optical information recording medium, a converging optical system including at least an objective lens, at least the objective lens and a photodetector for receiving the reflected light beam from the optical information recording medium. and an objective lens drive mechanism for holding at least the objective lens in a predetermined positional relationship with respect to the optical information recording medium, each of which is mounted and fixed to a casing, the optical information processing device comprising: An optical information processing device characterized in that the casing is formed using a metal plate using a press working method. (2) The optical information processing device according to claim 1, wherein a rib is provided on a part or all of the bent portion of the casing. (3) When the plate thickness of the casing is t, the height of the rib is set in the range of 2t to 5t, and the width is set in the range of 2t to 8t. Information processing device. (4) The optical information processing device according to any one of claims 1 to 3, characterized in that a half blanking is provided on the bottom or side surface of the casing. (5) The half-blanking groove is set to a width and length that provides a minute clearance with respect to the width or length of the optical components constituting the converging optical system and light-receiving optical system. 5. The optical information processing device according to claim 4, further comprising a stopper for positioning when the device is fixed. (6) The casing is made of any one of an Al alloy plate, a brass plate, a stainless steel plate, a mild steel plate, a zinc steel plate, a nickel silver plate, and a titanium alloy plate. The optical information processing device according to item 5. (7) The thickness t of the above casing is 0.5mm≦t≦2m
7. The optical information processing device according to claim 1, wherein the optical information processing device is set to a range of m. (8) The optical information processing device according to any one of claims 1 to 7, wherein at least one mounting burring tap is provided on a side surface of the casing and projects inward. (9) The optical information processing device according to any one of claims 1 to 8, characterized in that reinforcing materials are fixed to the corners of the four side plates of the casing. (10) The optical information processing device according to any one of claims 1 to 8, wherein each corner portion of the casing is joined by drawing.