JPH07225953A - Light source device - Google Patents

Abstract

PURPOSE:To regulate a collimator lens in its movement due to a temp. change and to enhance its productivity by constituting an inner diameter of a collimator lens holding part of a collimator holder smaller than an outside diameter of the collimator lens, notching slitwise the collimator holding part and force-fitting the collimator lens into this part. CONSTITUTION:The inner diameter of the collimator lens holding part 12 is constituted equally to or slightly smaller than the outside diameter of the collimator lens 2. Then, the holding part 12 is provided with slits 13 in several places at equal phase intervals in the circumferential direction to make an elastically displacable structure. When the lens 2 is inserted into the holding part 12, these elastic parts of the holding part 12 are spread outside to hold elastically the lens 2. An adhessive is applied to the slits 13 of the holding part 12 and the outer circumferential surface part of the lens 2 at more than one spot respectively, and they are bonded to be fixed up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a laser beam,
The present invention relates to a device for recording or reproducing information, for example, a light source device of an optical head in a magneto-optical disk device or the like.

[0002]

2. Description of the Related Art A conventional magneto-optical disk optical system is shown in FIG.
The light emitted from the laser diode 1 is converted into parallel light by passing through the collimator lens 2 here. Then, the light passes through the beam splitter 20 and the flip-up mirror 24, enters the objective lens 25, and then is focused on the recording surface of the disc (not shown). The beam reflected from the disc is again reflected by the flip-up mirror 24 and the beam splitter 2.
After passing 0, it enters the sensor 23 through the condenser lens 21 and the prism 22, and the disc information and the servo signal are read.

In such a structure, in order to collimate the light emitted from the collimator lens 2 and perform accurate data recording / reproduction, the beam emitting position of the laser diode 1 and the relative position of the collimator lens 2 are highly accurate. Therefore, adjustment means in the front-back direction of the optical axis is required. Then, in order to perform this adjustment, as shown in FIG. 5, the collimator lens 2 is held by a cylindrical collimator holder 3, and the entire collimator holder 3 is moved back and forth while monitoring the light emitted from the collimator lens 2. The method of letting is adopted. For holding the collimator lens 2 with respect to the collimator lens holder 3 at this time, for example, as shown in FIG. 6, an ultraviolet curable adhesive 5 is used. That is, the collimator lens 2 is inserted into the collimator lens holding portion 4 of the collimator holder 3 having an inner diameter that is several to several tens of microns larger than the outer diameter of the collimator lens 2, and a part or all of the outer peripheral side surface of the collimator lens 2 is inserted. The adhesive is adhered via the ultraviolet curable adhesive 5 applied to the circumference, and the adhesive 5 is cured by irradiating the adhesive with ultraviolet light, and is fixedly held.

[0004]

However, in the above-mentioned collimator lens holding method, the ultraviolet-curable adhesive layer 5 is present in the minute gap between the collimator lens 2 and the collimator holder 3, which causes a change in temperature. Due to the expansion and contraction of the adhesive, the collimator lens 2 slightly moves within the collimator holder 3, and accordingly, the light passing through the collimator lens may be tilted with respect to the initially adjusted position. Conceivable.

As a result, there is a possibility that the information signal cannot be recorded and reproduced accurately. Further, conventionally, in order to minimize this inclination, it has been devised to improve the processing accuracy of the outer diameter of the collimator lens and the inner diameter of the lens holding portion of the collimator holder to make the gap as small as possible. It is necessary to produce metal materials such as brass and brass by cutting, which has lower productivity than injection processing using resin, and is not practical in terms of mass production.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and at the same time restricts the movement of the collimator lens due to temperature change, substantially manufactures the collimator lens and the lens holder by a highly productive processing method. It is intended to provide a light source device devised so as to be good.

[0007]

Therefore, in the present invention,
The inner diameter of the collimator lens holding part of the collimator holder is made smaller than the outer diameter of the collimator lens, and the collimator lens holding part is notched in a slit shape to allow elastic displacement. Let them do it.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same parts as those in the above-mentioned conventional example are denoted by the same reference numerals. FIG. 1 shows a first embodiment of the present invention. In FIG.
Reference numeral 2 is a collimator lens, and 10 is a collimator holder. The collimator holder 10 is a lens barrel unit 1 for front-back adjustment.
1 and a collimator lens holding portion 12, and the inner diameter of the collimator lens holding portion 12 is configured to be the same as or slightly smaller than the outer diameter of the collimator lens 2. Further, the collimator lens holding unit 12 is
The slits 13 extending in the axial direction of the cylinder are provided at several positions in the radial direction from the center of the cylinder, in the embodiment, at four positions with a uniform phase difference in the circumferential direction. The structure is elastically displaceable.

In such a configuration, the collimator lens 2
Is inserted into the collimator lens holding portion 12, the outer diameter of the collimator lens 2 is slightly larger, so that the elastic portion of the collimator lens holding portion 12 expands outward, and the elastic force at this time makes the collimator lens 2 elastic. Can be held. Further, the outer diameter of the collimator lens holding portion 12 is configured to be smaller than the outer diameter of the lens barrel portion 11, and even if the collimator lens 2 is inserted and spreads outward, it may affect the movement of the collimator holder 10. Absent. Further, the adhesive is used for the collimator lens holding portion 12
The slit portion 13 and the outer peripheral side surface portion of the collimator lens 2 are applied at one or more places, and both are adhered and fixed.

Next, another embodiment of the present invention will be described with reference to FIG.
And it demonstrates in FIG. FIG. 2 shows a system in which the collimator lens 2 is elastically supported by providing the same slits as in the above-described embodiment. In FIG. 2, the collimator lens holding portion 16 is used to regulate the position of the collimator lens 2 in the circumferential direction. The hook portion 18 for restricting the axial position of the collimator lens 2 is provided at the tip of the elastic portion.

Therefore, when the collimator lens 2 is inserted,
This hook portion 18 expands outward due to its elasticity, allows the collimator lens 2 to enter, and when the surface portion of the collimator lens 1 reaches the hook portion 18, the hook portion 18 restores its elasticity to cover the surface of the collimator lens 2. It becomes a state of being pinched, and elastically holds the collimator lens 1. This snap-fit method allows easy assembly without the use of adhesives.

FIG. 3 shows a system in which the collimator lens 2 is elastically supported by providing the same slits as in the first embodiment. In FIG. 3, the circumferential position of the collimator lens 2 is restricted by the collimator lens. The protrusions 22 and 23 provided on the inner circumference of the holding portion 21
An adhesive for bonding the collimator lens holding portion 21 and the collimator lens 2 is interposed in the concave portion between the three. As a result, the adhesive can be applied to the entire circumference of the outer circumference of the collimator lens, and the holding force is increased.

[0013]

As described above, according to the present invention, the inner diameter of the collimator lens holding portion of the collimator holder is configured to be smaller than the outer diameter of the collimator lens, and the collimator lens holding portion is notched in a slit shape to allow elastic displacement. It is possible to hold the fixed collimator lens by the elastic force of the collimator lens holding portion when the collimator lens is inserted into the collimator holder and to fix the movement of the collimator lens due to temperature change. Further, at the same time, since the holding method by the elastic force is adopted, even if the processing accuracy of the outer diameter of the collimator lens and the inner diameter of the lens holder is loosened, the optical accuracy is not adversely affected, and high productivity can be maintained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a collimator lens and a collimator holder showing an embodiment of the present invention.

FIG. 2 is a sectional view of a collimator lens and a collimator holder showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a collimator lens and a collimator holder showing another embodiment of the present invention.

FIG. 4 is a perspective view showing the arrangement of a general optical system.

FIG. 5 is a vertical sectional side view of a conventional example.

FIG. 6 is a cross-sectional view of a conventional collimator lens and a collimator holder.

[Explanation of symbols]

 1 Laser diode 2 Collimator lens 3 Collimator holder 4 Collimator lens holding part 5 UV curable adhesive 10 Collimator holder 11 Collimator adjusting part 12, 16, 21 Collimator holding part 13 Slit 17, 22, 23 Convex part 18 Hook part

Claims (4)

[Claims] 1. In a light source device in which a light beam emitted from a laser diode is converted into a parallel light beam by a collimator lens, a cylindrical collimator holder for holding the collimator lens so that it can be adjusted back and forth with respect to the optical axis direction is An adjusting part for sliding back and forth in the optical axis direction, and an outer diameter smaller than the adjusting part, and a plurality of slits extending in the optical axis direction provided in the cylindrical part of the adjusting part for holding the collimator lens. The collimator lens holding part is configured with an inner diameter slightly smaller than the outer diameter of the collimator lens, and is elastically displaced by inserting the collimator lens, so that the elastic force holds the collimator lens. A light source device characterized by being configured. 2. A slit portion of the collimator holder,
The light source device according to claim 1, wherein the outer peripheral side surface of the collimator lens is fixed to each other by adhesion. 3. The collimator lens holding portion of the collimator holder includes a convex portion for positioning the collimator lens and a concave portion for filling the adhesive.
The light source device according to. 4. The light source device according to claim 1, wherein a free end side of the collimator lens holding portion of the collimator holder has a snap fit, and the collimator lens is sandwiched and fixed.