JPH02173945A - Optical head - Google Patents

Abstract

PURPOSE:To easily work a semiconductor laser holder, to minimize the positional deviation in the luminous flux direction of the semiconductor laser due to the change of the external temperature, and to eliminate a need of a high frequency generator attaching spacer by providing the semiconductor laser holder with a fitting recessed part whose depth is shorter than the thickness of the rim of the semiconductor laser. CONSTITUTION:A semiconductor laser holder 12 consists of a member which has an overall thickness (r) and has a fitting recessed part 13 having a depth (q) where a semiconductor laser 1 whose rim 1a has a thickness (p) is fitted and held, and p>q is true. Since the rim of the semiconductor laser main body is directly joined to an optical block when the semiconductor laser is fixed to the optical block, the semiconductor laser holder is easily worked, and the positional deviation in the luminous flux direction of the semiconductor laser due to the change of the external temperature is minimized, and the high frequency generator attaching spacer is unnecessary.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical head of an optical disk device or the like.

Conventional Technology The modern era is called the information age, and the technology development of high-density, large-capacity memory, which forms the core of this age, is actively being carried out.

In addition to the above-mentioned high density and large capacity, the capabilities required of memory include high reliability and high speed access, and optical disk memory is attracting the most attention as a device that satisfies all of these requirements.

Optical disk memories optically record information on a recording medium, and recently a lot of research has been conducted on magneto-optical disks that can also erase recorded information. The present invention relates to an optical head in an optical disk memory as described above.

Conventionally, a large number of research publications have been made regarding technologies related to optical heads, which are described in detail in literature related to optical disk memories.

Hereinafter, the conventional optical head as described above will be explained with reference to the drawings.

FIG. 5 is a schematic diagram of a conventional optical head. 1
is a semiconductor laser, la is a semiconductor laser rim, 2 is an optical block, 3 is a conventional semiconductor laser holder, 4 is a high frequency generator, 5 is a spacer for mounting the high frequency generator, 6 is a collimating lens, 7 is a beam shaping means, 8 9 is a reflected light separation means, 9 is an objective lens, 10 is a disk serving as an information recording medium, and 11 is a detection means.

The operation of the conventional example configured as described above will be explained below.

The basic premise is that in order to reproduce data recorded on an optical disk using a high-output semiconductor laser, it is necessary to closely couple a high-frequency generator to the semiconductor laser and suppress noise by superimposing high-frequency waves.

The semiconductor laser 1 is fitted and held in a semiconductor laser holder 3. In the semiconductor laser holder 3, end surfaces B of two examples of optical blocks of the semiconductor laser holder 3 are closely fixed to the optical block 2. A high frequency generator 4 is fixed to the semiconductor laser 1 via a spacer 5 for mounting the high frequency generator. The diverging light from the semiconductor laser 1 fixed as described above is converted into substantially elliptical parallel light by the collimating lens 6, and converted into substantially circular parallel light by the beam shaping means 7.

The output light from the beam shaping means 7 is focused onto a disk 10 by an objective lens 9, and information is recorded and reproduced. The reflected light from the disk 1o follows the opposite path,
The reflected light is reflected by the reflected light separating means 8 and enters the detecting means 11, where information signals, focus error signals, trunking error signals, etc. on the disk lo are detected.

Problems to be Solved by the Invention However, in the above configuration, when the semiconductor laser l is fixed to the optical block 2, the semiconductor laser holder 3
In order to tightly fix the end surface B of the two examples of optical blocks and the optical block 2, the end surface A of the semiconductor laser rim la, which is the reference surface of the semiconductor laser 1, is not joined to the optical block 2. Therefore, the semiconductor laser 1 can be placed in the optical block 2 without tilting.
In order to fix the semiconductor laser holder 3 to the optical block 2 side, the end face B of the semiconductor laser holder 3 and the recess for fitting the semiconductor laser l must be processed and finished with high precision.

In addition, expansion and contraction of the semiconductor laser holder 3 due to changes in external temperature also causes positional deviation of the semiconductor laser 1 in the optical axis direction. The attachment had the problem of requiring a spacer 5.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to facilitate the processing of the semiconductor laser holder 3, further minimize the positional shift of the semiconductor laser 1 in the direction of the light beam due to changes in external temperature, and in addition, The high frequency generator attachment is intended to provide an optical head that eliminates the need for spacers.

Means for Solving the Problems In order to achieve the above object, the optical system of the present invention includes a fitting recess with a depth of 9 for fitting and holding a semiconductor laser holder with a rim having a thickness p. It is composed of a member having a total thickness r, and is characterized in that P>9.

In addition, a protrusion for positioning the semiconductor laser may be provided on the inner periphery of the semiconductor laser fitting recess of the semiconductor laser holder. In addition, the semiconductor laser holder
A screw is a fixing component that has a screw through hole for fixing to the optical block at a position symmetrical to the center of the semiconductor laser fitting recess, and is inserted into the screw through hole within the total thickness r of the semiconductor laser holder. For the total height S of the screw head, washer, etc., there is a depth L in the surface opposite to the semiconductor laser fitting recess.
It is also possible to have a screw-fastening recess of , and a configuration characterized in that t>s.

Effects of the present invention With the above-described configuration, when a semiconductor laser is fixed to an optical block, the rim of the semiconductor laser body is directly joined to the optical block, so processing of the semiconductor laser holder is facilitated, and furthermore, the rim of the semiconductor laser body is directly joined to the optical block. Positional deviations due to temperature changes can be minimized, and in addition, spacers can be eliminated when mounting the high frequency generator.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 shows a schematic diagram of an optical head in an embodiment of the present invention. In FIG. 1, l is a semiconductor laser,
2 is an optical block, 12 is a semiconductor laser holder in this embodiment, 4 is a high frequency generator, 6 is a collimating lens,
7 is a beam shaping means, 8 is a reflected light separating means, 9 is an objective lens, 10 is a disk which is an information recording medium, and 11 is an information signal detecting means.

The operation of an embodiment of the optical head configured as described above will be described below.

In this embodiment, each operation with respect to the light emitted from the semiconductor laser 1 is similar to the conventional example described using FIG. 5.

From the above points, the semiconductor laser 1 which is the main part of this embodiment
．． Semiconductor laser holder 12. Optical block 2. The configuration of the high frequency generator 4 is shown in FIG. 2 below.

This will be explained using FIGS. 3 and 4. Fig. 2 is a schematic diagram of the main parts in Fig. 1, Fig. 3 is a perspective view of a semiconductor laser holder, which is the main element of this embodiment, and Fig. 4 is a trigonometry diagram of Fig. 3. be. In FIG. 2, 1 is a semiconductor laser, 1a is a semiconductor laser rim, 2 is an optical block,
4 is a high frequency generator, 12 is a semiconductor laser holder according to the present invention, 13 is a semiconductor laser fitting recess, 15 is a through hole for inserting a fixing screw, 16 is a screw fixing recess, and 17 is a fixing screw. The semiconductor laser holder 12 is composed of a member having a total thickness r and having a fitting recess with a depth of 9 for fitting and holding the semiconductor laser 1 having the semiconductor laser rim 1a having a thickness p. Here, if p>q, the end surface A of the semiconductor laser rim 1a is bonded and fixed to the optical block 2, thereby preventing the influence of expansion and contraction of the semiconductor laser holder 12 due to external temperature changes, and reducing the luminous flux of the semiconductor laser 1. It becomes possible to minimize directional positional deviation. In addition, it is also possible to reduce the accuracy of the semiconductor laser fitting recess of the semiconductor laser holder 12 and facilitate processing.

Furthermore, the semiconductor laser holder 12 is provided with a through hole 15 for a screw for fixing it to the optical block 2 at a centrally symmetrical position of the semiconductor laser fitting recess 13.
Within the total thickness r of
By having a deep screw fixing recess 16 in the opposite surface to the semiconductor laser fitting recess 13 and configuring t>s, firm fixation with screws is possible. Furthermore, by providing the screw fixing recess 16, the semiconductor laser holder 1
No spacer is required for attaching the generator to the opposite end surface C of the optical block 2 of No. 2, making it possible to reduce the number of parts and the number of assembly steps. Further, if the semiconductor laser holder 12 is provided with a protrusion 14 for positioning the semiconductor laser on the inner circumference of the recess 13 for fitting the semiconductor laser as shown in FIG. Become.

Effects of the Invention As described above, the present invention provides an optical block by providing a semiconductor laser holder for holding and fixing a semiconductor laser, which is a light source of an optical head, with a fitting recess having a depth smaller than the thickness of the semiconductor laser rim. Since the end face of the semiconductor laser rim, which is the reference plane, is bonded and fixed to the rim, it is possible to minimize the influence of the semiconductor laser holder's expansion and contraction due to external temperature changes on the position of the semiconductor laser in the light beam direction. . In addition, it is also possible to lower the accuracy of the semiconductor laser fitting recess of the semiconductor laser holder and facilitate processing.

The semiconductor laser holder also has a screw through hole for fixing it to the optical block at a centrally symmetrical position to the semiconductor laser fitting recess, and a fixing component that is inserted into the screw through hole within the entire thickness of the semiconductor laser holder. By providing a screw fixing recess with a depth greater than the total height of the screws, washers, etc. on the opposite side of the semiconductor laser fitting recess, the optical block of the semiconductor laser holder can be Since the high frequency generator can be fixed close to the side end face, no spacer is required for mounting the high frequency generator. Therefore, it is possible to reduce the number of parts and the number of assembly steps. Furthermore, by providing a protrusion for positioning the semiconductor laser on the inner periphery of the recess for fitting the semiconductor laser in the semiconductor laser holder, an excellent optical head that facilitates the horizontal and vertical positioning of the emitted light of the semiconductor laser is realized. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an optical head in one embodiment of the present invention, FIG. 2 is a schematic diagram of the main parts in FIG. 1, and FIG. 4
The figure is a schematic diagram of FIG. 3 using trigonometry, and FIG. 5 is a schematic diagram of a conventional optical head. 1... Semiconductor laser, 1a... Semiconductor laser rim, 2... Optical block, 3...
...Conventional semiconductor laser holder, 4...High frequency generator, 5...Spacer for high frequency generator installation, 6...Collimating lens, 7...・Beam shaping means, 8...Reflected light separation means, 9...
...Objective lens, 10...Disk serving as an information recording medium, 11...Detection means, 12...
... Semiconductor laser holder in the present invention, 13...
... Semiconductor laser fitting recess, 14 ... Semiconductor laser positioning protrusion, 15 ... Fixing screw insertion through hole, 16 ... Screw fixing recess, 17 ...・
・Fixing screw. Name of agent: Patent attorney Shigetaka Awano

Claims (3)

[Claims] (1) an information recording medium, a semiconductor laser as a light source, and a semiconductor laser holder that fixedly holds the semiconductor laser;
a high frequency generator fixed close to the semiconductor laser; an objective lens for condensing the output light of the semiconductor laser onto the information recording medium; means for separating reflected light from the information recording medium; and the information recording medium. The semiconductor laser holder includes a means for detecting a focus error signal, a tracking error signal, an information signal, etc. by receiving reflected light from the medium through the separation means, and an optical block incorporating each of the components, and the semiconductor laser holder , an optical head characterized in that it is a member having a total thickness r and a fitting recess having a depth q into which a semiconductor laser having a rim having a thickness p is fitted, and p>q. (2) The optical head according to claim 1, wherein the semiconductor laser holder has a protrusion for positioning the semiconductor laser on the inner periphery of the recess for fitting the semiconductor laser. (3) The optical head according to claim 1, wherein the semiconductor laser holder has a screw through hole for fixing to the optical block at a position symmetrical to the center of the semiconductor laser fitting recess. (4) The semiconductor laser holder has a total thickness r relative to the total height s of the screw head, washer, etc. of the screw that is the fixing part inserted into the screw through hole for fixing the semiconductor laser holder to the optical block. It has a screw fixing recess with a depth t on the opposite surface to the semiconductor laser fitting recess, and t>s
The optical head according to claim 3, characterized in that: