JPH0521816A - Manufacture of optical element - Google Patents

Abstract

PURPOSE:To mount a photodiode and a semiconductor laser with extremely high positional accuracy. CONSTITUTION:In a light element wherein a photoelectric transfer element which receives signals from a light source and an optical memory medium are stored in a same package, a semiconductor 102 is mounted with the mounting faces of the substrates 106A and 106B of a pedestal 104 as the datum planes in the direction of z axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical element constituting an optical head in the field of optical storage for recording and reproducing information by using light.

[0002]

2. Description of the Related Art Conventionally, a diffractive means composed of two unequal periodic diffraction grating regions for dividing light from an optical storage medium in the direction of four photoelectric conversion elements, and an astigmatism composed of the diffractive means and a condenser lens. Aberration generating means and a strip-shaped 4 in which the major axis direction is arranged radially about the optical axis of the 0th-order diffracted light of the diffracting means.
In the method of manufacturing an optical element having two photoelectric conversion elements and a light source, the mounting method of the light source is not limited in any way.

[0003]

However, in the case of the optical head in which the light source, the photoelectric conversion element and the like are mounted in one package as described above, the photoelectric conversion element and the light source must be mounted with extremely high positional accuracy for focusing. The error and tracking error signals cannot be obtained.

Therefore, the present invention solves such a problem, and an object of the present invention is to provide a method of manufacturing an optical element capable of mounting a light source with extremely high positional accuracy.

[0005]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a diffraction consisting of two unequal periodic diffraction grating regions for dividing light from an optical storage medium into four photoelectric conversion elements. Means, astigmatism generating means including the diffracting means and a condenser lens, and four strip-shaped photoelectric conversion elements in which the major axis direction is arranged radially around the optical axis of the 0th-order diffracted light of the diffracting means. And a light source, wherein the light source is mounted on the basis of a pedestal surface on which the photoelectric conversion element is mounted.

[0006]

FIG. 1 is a front view (a) and a top view (b) of an optical element showing an embodiment of the present invention. The pedestal 104 is a part of the package, the bottom surface of the package is parallel to the paper surface of FIG. 1A, and the pedestal 104 is projected on the bottom surface. This pedestal 10
A method of mounting the light source and the photoelectric conversion element on the optical disc 4 will be described below.

First, the submount 103 is die-bonded to the pedestal 104 from the y-axis direction. At this time, two straight lines 107 and 108 are displayed in parallel with the x-axis on the monitor screen of the mounting apparatus, and the distance between them is the distance between the light source and the light-receiving surface of the first-order diffracted light in the z-axis direction and the next time. The magnification on the screen is equal to the thickness of the photoelectric conversion element substrate that receives the folded light. First, on the monitor screen, the straight line 107 is aligned with the photoelectric conversion element substrate mounting surface of the pedestal 104, and then die-bonded from the y-axis direction to the pedestal 104 so that the end surface of the submount 103 is aligned with the straight line 108. Die bonding is performed by applying heat to the fusing metal vapor-deposited on the mounting surface of the submount 103 while pressing it while melting.

Next, the semiconductor laser 102 serving as a light source is die-bonded to the submount 103 in the y-axis direction. Also at this time, positioning is performed so that the emission end face of the semiconductor laser 102 and the straight line 108 are aligned with each other, and heat is applied to the fusion metal deposited on the surface of the semiconductor laser 102 while being melted and pressed.

Due to such positioning, the light source is mounted on the basis of the pedestal surface of the photoelectric conversion element even if the light source pedestal end of the pedestal 104 and the photoelectric conversion element pedestal surface are displaced in the z-axis direction. Therefore, by managing only the thickness of the photoelectric conversion element substrate in the z-axis direction, the distance between the light source and the photoelectric conversion element light-receiving surface can be mounted in a correct positional relationship without fail.

Thereafter, the semiconductor laser 102 and the terminals provided on the package are wire-bonded to each other to form the semiconductor laser 10.
2 can be driven.

The four photodiodes 105A, 105B, 105C and 105D serving as photoelectric conversion elements are provided on the substrate 106A, respectively.
B, the photodiodes 105C and 105 on the substrate 106B.
D is formed.

When mounting the substrates 106A and 106B, the semiconductor laser 102 is driven to emit light. Four photodiodes emit light 1 while looking at the monitor screen of the mounting device.
The substrates 106A and 106B are die-bonded from the z-axis direction so as to be symmetrically arranged in the y-axis passing through 01.

FIG. 2 is a perspective view showing a package after mounting according to the embodiment of the present invention. In this way, the semiconductor laser 102,
And substrates 106A and 106B provided with photodiodes
After mounting, the electrodes and terminals of each element are wire-bonded. Further, polarizing plates are used as analyzers for the substrates 106A and 106A.
The optical element is completed by arranging it in front of B and arranging an astigmatism generating means composed of a condenser lens and unequal period diffracted photons.

The optical element manufactured in this manner can constitute an extremely small-sized optical head because the optical parts necessary for detecting the optical signal and the error signal only need the diffraction means.

[0015]

As described above, according to the present invention, the photoelectric conversion element can be mounted on the light source with extremely high positional accuracy. In such an optical element mounted in the same package, the area of the photoelectric conversion element is small and the post-manufacturing position adjustment cannot be performed. Therefore, the allowable range of mounting positional deviation is severe. However, in the present invention,
Even if the pedestal end for the light source and the photoelectric conversion element pedestal surface are misaligned in the optical axis direction, the light source is mounted with the pedestal surface of the photoelectric conversion element as a reference, so the thickness of the photoelectric conversion element substrate in the optical axis direction If managed only, the distance between the light source and the light receiving surface of the photoelectric conversion element can always be mounted in a correct positional relationship. That is, the position accuracy of the pedestal surface can be loosened, and the package processing cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a front view of an optical element according to an embodiment of the present invention (a).
Is a top view (b).

FIG. 2 is a perspective view showing a package after mounting in the embodiment of the present invention.

[Explanation of symbols]

101 light emitting point 102 semiconductor laser 103 submount 104 pedestal 105A, 105B, 105C, 105D photodiode 106A, 106B substrate 107, 108 straight line drawn on monitor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H01L 33/00 N 8934-4M H01S 3/18 9170-4M

Claims (1)

Claim: What is claimed is: 1. A diffractive means comprising two unequal-period diffraction grating regions for dividing light from an optical storage medium in the direction of four photoelectric conversion elements, the diffractive means and a condenser lens. A method of manufacturing an optical element comprising: an astigmatism generating means, and four strip-shaped photoelectric conversion elements whose major axis direction is arranged radially around the optical axis of the 0th-order diffracted light of the diffracting means. 2. The method for manufacturing an optical element according to, wherein the light source is mounted on the basis of a pedestal surface on which the photoelectric conversion element is mounted.