JPH03113842A - Laser light source device - Google Patents

Abstract

PURPOSE:To obtain a laser driver of a single elective power source having high reliability so as to reduce the number of parts and the cost by constituting a collimator lens barrel of ceramics. CONSTITUTION:The collimator lens barrel 1d holding a collimator lens 1b is constituted of the ceramics. The collimator lens barrel 1d has, therefore, a small coefft. of thermal expansion and can make correction of a back focus. In addition, the collimator lens barrel 1d itself has an electrical insulating charac teristic. The electrical insulating parts which are heretofor variously used with conventional devices are omitted in this way and the increase of the cost at the time of using the lens barrel with the single power source is obviated. A molding method is adopted for production and the cost reduction is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a laser light source device used in an optical information processing device that records/reproduces information on a recording medium such as an optical disk.

(Prior Art) This type of laser light source device uses a collimator lens to convert a diverging light beam output from a semiconductor laser into a parallel light beam, and guides the parallel light beam to an optical system of an optical head. In this case, the collimator lens is held in a collimator lens barrel and incorporated into the semiconductor laser, and such a unit is usually called a collimator unit.

The principle of adjustment in assembling a conventionally used collimator unit will be explained with reference to FIG.

Here, the semiconductor laser 1a is adjusted in the coordinate axis YZ direction, and the collimator lens 1b is adjusted in the coordinate axis X direction. A collimator unit that can make such adjustments is the 4th collimator unit.
The configuration of the figure is known. The semiconductor laser 1a is held by a laser spacer IC, the collimator lens 1b is housed in a collimator lens barrel 1d,
It is clamped and fixed between a compression coil spring if disposed inside and a presser ring 1e screwed onto the collimator lens barrel 1d. And the above laser spacer IC
and a flange formed at the base of the collimator lens barrel 1d are connected with a screw 1h via an electrically insulating washer 1g, and both are separately attached to the optical head with a screw 11 via the same washer 1g. .

In such a configuration, the collimator lens 1b is adjusted in position in the direction of the coordinate axis X by the screwing of the retainer ring 1e, and the semiconductor laser 1a is adjusted with the screw 1h loosened.
The position of the laser spacer 1c is adjusted on the contact surface of the flange in the YZ force direction of the coordinate axes. Screw 1h after adjustment
and 11 are tightened to establish a connection between the flange portion and the laser spacer IC.

The collimator unit 12 configured in this way is
As shown in FIG. 3, it is mounted on a carriage 17 together with an optical head 16 incorporating an optical system, but when the size of the drive is limited, such as with a full-hide or half-hide drive, cost and Considering usage efficiency, it is usually used without a negative power supply.

In addition, in order to correct the expansion and contraction of the back focus of the collimator lens 1b due to temperature and the wavelength shift of the semiconductor laser 1a, a material with a small coefficient of thermal expansion, such as an iron-based metal, is usually used for the collimator lens barrel 1d. ing.

(Problems to be Solved by the Invention) Therefore, in order to avoid having a negative power source as described above, an electrical insulating washer 1g is provided, and furthermore, the collimator lens barrel 1d and its flange are provided with an electrically insulating washer 1g.
1 m of insulating material at the position where it contacts the optical head
Or 1! This increases the number of parts. Furthermore, when iron-based metals are used, expensive cutting is required to construct the collimator lens barrel. Furthermore, if the screws 1h and 1g are tightened too much, the insulating washer 1g, which is generally made of resin or the like, will be deformed and will no longer function as an insulator, potentially causing an electrical short circuit to the optical head 16.

(Object of the Invention) The present invention has been made based on the above circumstances, and although it is a material with a low coefficient of thermal expansion that can correct the back focus of the collimator lens depending on temperature, it can be used in various ways for insulation even with single power supply specifications. The present invention aims to provide a laser light source device in which the material of the collimator lens barrel is specified so that parts can be omitted, and the manufacturing cost thereof can be reduced.

(Means for Solving the Problems) For this reason, the present invention provides optical information that records information by irradiating an information recording medium with a light beam spot or reproduces information using reflected light from the recording medium. In order to generate the above-mentioned light beam in the processing device, the collimator lens barrel holding the above-mentioned collimator lens is made of ceramic in a laser light source device in which the light flux from the laser light source is made into a parallel light flux by a collimator lens in order to guide it to the optical system of the optical head. It is configured.

(Function) Therefore, as in the case of conventional iron-based metals,
The collimator lens barrel has a small coefficient of thermal expansion and can perform back focus correction. Moreover, since the collimator lens barrel itself is electrically insulating, various electrically insulating parts used in conventional devices can be omitted, and when used with a single power source, there is no need to incur high costs. do not have. In addition, in terms of manufacturing, molding methods can be used, leading to cost reductions.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to FIGS. 1 and 2. Note that the same parts as those in the description of the conventional example are given the same reference numerals and the description thereof will be omitted. That is, the feature of the present invention is that the collimator lens barrel 1d is made of ceramic, and therefore the insulating washer 1g and the insulating material 1m are made of ceramic.

11 is omitted. As the ceramic of the collimator lens barrel 1d, for example, silicon carbide (S
iC), alumina (8j!zOi), zirconia (Zr
Ot) etc. These characteristics are shown in Table 1 below.
It is as follows. For comparison, iron is also listed.

In addition, it is clear that it is lighter than steel in terms of specific gravity, and it can contribute to reducing the weight of the optical head as a whole.
It is also effective in reducing seek time.

In this embodiment, the backlash between the inner diameter of the collimator lens barrel 1d and the outer diameter of the collimator lens 1b directly becomes the inclination of the optical axis, so the inner diameter of the collimator lens barrel 1d is finished with too rough precision. That must be avoided. For this reason, the collimator lens barrel 1
After molding d by an injection molding method or the like, it is desirable to finish only the inner diameter thereof so that the normal tolerance (diameter) is within ±3 μm. In addition, the collimator lens 1b
When the position adjustment (in the X direction) is completed, it is preferable to drop an instant adhesive into the adhesive groove 1j to adhere the collimator lens barrel 1d and the collimator lens 1b. In particular, if the collimator lens barrel 1d is made of porous ceramic, this adhesion will become stronger. Therefore, high.

When the temperature changes to low temperature or when it is accidentally dropped,
Collimator lens 1b within collimator lens barrel 1ci
There is no risk of the film shaking or the adhesive peeling off.

Further, since no insulating washer is used, there is an advantage that the collimator lens unit 12 can be securely screwed onto the optical head 16 side, and the connection between the two will not become loose.

In FIGS. 1 and 2, reference numeral 1 indicates an injection port for the adhesive groove 1j, 14 indicates a flexible substrate for control signals, 11 indicates a linear motor, and 13 indicates a spindle morph for rotationally driving the recording medium. , 15 are guide rails for guiding the carriage 17.

(Effects of the Invention) The present invention has been described in detail above, and by configuring the collimator lens barrel with ceramic, it is possible to provide a highly reliable single-power laser driver, reduce the number of parts,
Many advantages can be obtained, such as cost reduction, strong adhesion between the collimator lens barrel and collimator lens, and bank focus correction.

[Brief explanation of drawings]

Fig. 1 is a longitudinal side view showing an embodiment of the present invention, Fig. 2 is a perspective view showing the installation status of an optical head incorporating a collimator lens unit, and Fig. 3 is a perspective view showing the adjustment principle in the collimator lens unit. 4 are longitudinal sectional side views of the conventional example. 1a... Semiconductor laser 1b... Collimator lens, IC... Laser spacer, Id... Collimator lens barrel, 1e... Holding ring, 1r... Compression coil spring, 12... Collimator lens unit,
16...Optical head.

Claims (1)

[Claims] A light beam from a laser light source is used to generate the light beam in an optical information processing device that irradiates a light beam spot onto an information recording medium to record information or reproduce information using reflected light from the recording medium. What is claimed is: 1. A laser light source device that uses a collimator lens to convert light into a parallel beam of light in order to guide it to an optical system of an optical head, wherein a collimator lens barrel that holds the collimator lens is made of ceramic.