JP2002260273A - Light emitting element mounted assembly and optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element mounted assembly that it is possible to monitor the optical output of each element independently without interference between the light emitting elements arranged close each other. SOLUTION: This is a light emitting element mounted assembly provided with the main board 14, a sub-board 7 mounted on the main board 14, the first and second light emitting elements 1, 2, a selective branching element 9 to branch only the front light of the first light emitting element 1 in the first and second directions and to change the path of the front light of the second light emitting element 2 substantially in the same direction as the first direction, the first output monitor element 3 having a light receiving region on the surface of the main board 14, and the second output monitor element 4 having a light receiving region on the surface of the sub-board 7. The second light emitting element 2 is disposed close to the first light emitting element 1 and controlled independently of the first light emitting element 1. The second output monitor element 4 has a light-receiving region at a specific location close to the rear light outputting point of the second light emitting element 2 on the surface of the sub-board 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-emitting element package for an optical pickup used in a reading device for an optical information recording medium such as an optical disk, and more particularly to a DVD.
The present invention relates to a light-emitting element package (semiconductor laser assembly) that integrates a plurality of semiconductor lasers and is suitable for a CD-R compatible playback system.

[0002]

2. Description of the Related Art In recent years, a CD, which is a consumer optical disk system that has been widely used, has recently been replaced with a higher density DV.
The D system has been proposed, commercialized, and spread.
In a DVD player as this reproducing apparatus, in order to avoid duplication of the apparatus and complexity of use, it is necessary to perform compatible reproduction with a CD. Similarly, a write-once type CD (CD-R) that can be reproduced by a CD player is also required to have a compatible reproduction function. Therefore, technologies for playing discs of various standards have been developed in this way,
Further, simplification of the configuration for realizing the above and cost reduction have become issues.

In particular, in a CD-R, a semiconductor laser light source in the 780 nm band different from the 650 nm band for DVD is indispensable because the reflectance of the recording medium has a large wavelength dependence. Therefore, a pickup optical system incorporating the two-wavelength light source has been developed. To reduce the size of the optical system, Japanese Patent Application Laid-Open No. H10-21577 proposes that two light emitting elements (semiconductor lasers) and a light receiving element are also integrated in the same package (hereinafter referred to as "first semiconductor element"). Conventional technology ").

In the first prior art, when a plurality of light emitting elements (semiconductor lasers) are arranged close to each other, a technique for detecting and controlling the outputs of two light sources independently, in particular, is disclosed. In the first related art, two light emitting elements (semiconductor lasers) are juxtaposed in a direction in which the resonator is parallel, and the light emitting elements (semiconductor lasers) are arranged so as to receive light emitted from the rear end thereof.
A light receiving element is arranged behind, and a light receiving area is further divided into two corresponding to each light emitting element (semiconductor laser).

By the way, in order to stably operate the semiconductor laser and, consequently, the servo system, the optical output of the semiconductor laser is monitored (monitored), and an automatic output control (APC) circuit by a closed loop control system based on the result is used. It is necessary to control to keep the light output constant. Here, in the above-described pickup using a semiconductor laser having a plurality of wavelengths, a plurality of light emitting elements (semiconductor lasers) are arranged in close proximity to each other.
It is necessary to control the optical outputs of these semiconductor lasers together.

[0006] For example, in a compatible player for CD and DVD, it is impossible to play both at the same time. Therefore, there is basically no need to monitor both at the same time. However, in practice, when the reflected light can be detected independently for each wavelength in the disc discriminating operation, the discrimination can be performed at a higher speed by simultaneous lighting. Also, even if both monitors are common, a semiconductor laser drive / control system (APC circuit) is required independently for each semiconductor laser. Are preferably electrically and optically separated.

In the method of the first prior art, when two light emitting elements (semiconductor lasers) are simultaneously emitted for some purpose, incident light from the other semiconductor laser adjacent to the semiconductor laser to be monitored can be blocked. There is the disadvantage that the operation of the APC circuit is inaccurate because there is no ("crosstalk").

Further, since the monitor light receiving section is arranged behind the semiconductor laser, the whole device becomes large, and there is a disadvantage that the height of the pickup and, consequently, the height of the optical disk apparatus is increased.

As one of the methods capable of solving these drawbacks, Japanese Patent Application Laid-Open No. 6-188519 discloses an example in which a wall-shaped light-shielding portion is arranged between two (rear) light-emitting points. Hereinafter, it is referred to as "second conventional technology.") However, the second prior art further complicates the structure and further increases the disadvantages of the above-mentioned device becoming large.

Japanese Patent Application Laid-Open No. 6-203404 discloses a method which uses a so-called "front monitor" method which does not use the backward emission light of a semiconductor laser and detects the outputs of a plurality of light emitting points independently, using a method completely different from the above. (Hereinafter referred to as “third prior art”). According to the third prior art, each output can be independently detected using forward emission light, but an aperture, a condenser lens, and the like are separately required, and the configuration of the pickup becomes conversely complicated and large. Has the disadvantage that

In view of the disadvantages of these systems, Japanese Patent Laid-Open
In JP-A-222768, the present inventor used two rear monitor regions by using regions where light beams are shielded by the outer shapes of two semiconductor lasers based on the outer shapes and arrangement conditions of the two semiconductor lasers as shown in FIGS. Thus, a structure for independently detecting the output of a semiconductor laser without crosstalk has been proposed (hereinafter, referred to as “the previous proposal”). As shown in the plan view (top view) of FIG. 7, the semiconductor laser assembly according to the above proposal has a first light emitting element (semiconductor laser) 1, a second light emitting element (semiconductor laser) 2, and a first output. The monitoring element 3 and the second output monitoring element 4 include a sub-mount (sub-board) 7.
Mounted on top. Then, the resonator length of the second light emitting element 2 is shorter than the resonator length of the first light emitting element 1, and each light beam reciprocating in the resonators of the first light emitting element 1 and the second light emitting element 2. The axes are substantially parallel to each other, and the first light emitting element 1 and the second light emitting element 2 are arranged such that the front end faces thereof are located on substantially the same plane. These are asymmetrically cleaved with respect to the stripe so that the light emitting points are as close as possible when juxtaposed. The first light emitting element 1 and the second light emitting element 2 are mounted on a submount (light receiving element substrate) also serving as the sub substrate 7. At this time, the front end faces are aligned so as to prevent ripples in the far-field image (far-field pattern: FFP), and at the same time, they are fixed so as to protrude slightly (several μm) from the outer shape of the sub-substrate 7. The first specific place for arranging the first output monitoring element 3 is located at the rear light emitting point P 2 _{b of} the second light emitting element (semiconductor laser chip) 2 and at the rear of the first light emitting element 1 and at the second position. of being limited to the angular range of the outer (left) of the parting line 8 through the line segment connecting the corners C ₁ on the side close to the light emitting element 2. on the other hand,
The second specific location for arranging the second output monitoring element 4 is located so as to be limited to a region in front of the extension 19 of the rear end face of the first light emitting element.

In this configuration, the first output monitoring element 3
On the other hand, the light emitted from the second light emitting element 2 is blocked by the outer shape of the first light emitting element 1 and cannot enter. On the other hand, the rear emission light of the first light-emitting element 1 is well detected by the first output monitoring element 3 in an area including the vicinity of the rear light-emitting point P _{1b where} the intensity is strongest, although the area is reduced. Also, the output light of the first light emitting element 1 is blocked by the rear end face of the first light emitting element 1 itself, and therefore cannot enter the second output monitoring element 4. Then, although the area of the backward emission light of the second light emitting element 2 is reduced, the backward emission point P having the strongest intensity is also obtained.
_{In the} area including the vicinity of _2b , the second output monitoring element 4 detects the signal well. As described above, according to the above proposal, the outputs of the two light emitting elements 1 and 2 arranged in parallel and close to each other and having different resonator lengths can be detected independently and accurately without mutual interference.

FIG. 8 is a perspective view showing a semiconductor laser assembly according to the above proposal. The first light emitting element 1 described above,
The submount 7 on which the second light-emitting element 2, the first output monitoring element 3, and the second output monitoring element 4 are mounted is mounted on the upper surface of the main substrate 14 together with the reflecting element 15 in a predetermined positional relationship. I have. A plurality of diffracted light receiving areas 51, 52, 53, 54 are formed on the main substrate 14.
These diffracted light receiving areas 51, 52, 53, 54 may be constituted by a photodiode array or the like.

In the semiconductor laser assembly according to the above proposal, two light beams emitted from the first semiconductor laser chip 1 and the second semiconductor laser chip 2 are reflected by the reflecting element 15.
Is emitted in a direction substantially perpendicular to the main substrate 14, passes through an optical element (not shown), and enters an optical information recording medium (not shown) as an object. Further, the light reflected by the object (optical information recording medium) reenters the optical element following the same optical path in reverse. This light beam is branched by an optical element into an optimal optical path, and the optical path is changed. The optical element irradiates a plurality of diffracted light receiving areas 51, 52, 53, and 54 to obtain reproduction signals, and obtains these diffracted light receiving areas 51, 52, and. 53,5
An electronic circuit (not shown) connected to 4 can execute predetermined arithmetic processing between divided regions to obtain an error signal such as focus and tracking.

[0015]

Although the prior proposals generally solve the disadvantages of the first to third conventional examples, they still have the following problems. (A) Since the monitor is basically a rear monitor, the size of the device (semiconductor laser assembly) is large in the longitudinal direction of the semiconductor laser resonator, and there is a restriction in reducing the thickness of the device when incorporated in a pickup.

(B) As shown in FIG. 7, even if two independent first and second output monitoring elements 3 and 4 are provided on the same semiconductor substrate, the n-pole (cathode) of the photodiode Both sides are common to the semiconductor substrates. In the output control (APC) of the semiconductor laser, the p and n polarities of both the semiconductor laser and the monitor may be set to a plurality of common (common) relations according to the requirements of the circuit side. In this case, there is a great restriction in setting the polarity relationship between the two semiconductor lasers. That is, since the light receiving regions of the two photodiodes are formed on the same submount (semiconductor substrate), the n poles of the photodiodes have the same potential and cannot be completely separated on a circuit.

(C) In particular, the semiconductor laser for DVD (on the short wavelength side) employs a method of increasing the reflectance of the rear end face in order to compensate for the characteristic deterioration at high temperature. May not be.

The present invention focuses on the above problems and aims to solve the plurality of problems simultaneously while having the advantages of the above proposals shown in FIGS. 7 and 8.

More specifically, a plurality of light emitting elements (semiconductor lasers) are arranged close to each other, and each optical output is independently and accurately detected without complicating the configuration and without mutual interference (crosstalk). It is an object of the present invention to provide a light emitting element package (integrated optical assembly) that can be used.

Another object of the present invention is to accurately and independently detect the outputs of light emitting elements (semiconductor lasers) having different wavelengths and control each light emitting element.
An object of the present invention is to provide a light-emitting element package that can be easily miniaturized.

Still another object of the present invention is to provide an optical system such as an optical pickup which can be miniaturized and easily separated on a circuit.

[0022]

Means for Solving the Problems In order to achieve the above object, a first feature of the present invention is that a main substrate, a sub-substrate mounted on the main substrate, and a sub-substrate mounted on the sub-substrate. Only the first and second light emitting elements, the optical path of the forward emission light of the first light emitting element are branched in the first and second directions, and the optical path of the forward emission light of the second light emitting element is shifted in the first direction. And a first output monitoring element having a light receiving area on the surface of the main substrate, and a second output monitoring element having a light receiving area on the surface of the sub-substrate. The gist of the invention is that the light-emitting element mounting body is provided. The main substrate and the sub-substrate are composed of semiconductor chips. The “second light-emitting element” is a light-emitting element that is disposed close to the first light-emitting element on the sub-substrate and whose output is controlled independently of the first light-emitting element. The “second output monitoring element” has a light receiving area disposed on the surface of the sub-substrate at a position adjacent to the rear light emitting point of the second light emitting element, and the light emitting area at the close position is used to emit light backward of the second light emitting element. An output monitoring element that receives an output.

For example, the resonator length of the second light emitting element is shorter than the resonator length of the first light emitting element, and the front end faces of the first and second light emitting elements are located substantially on the same plane. In this case, the “proximity position” where the second output monitoring element is arranged is preferably limited to a region in front of an extension of the rear end face of the first light emitting element. At this time, the first and second
Of course, it is preferable to make the optical axes reciprocating in the resonator of the light emitting element substantially parallel to each other. That is, “the proximity position where the second output monitoring element is arranged”
It is preferable that the first and second emission angle ranges having the vertexes of the respective rear emission points of the first and second light emitting elements do not overlap each other. The output of the first light emitting element can be controlled by a so-called “front monitor”.

According to the light emitting element mounting body according to the first feature of the present invention, the dimension "L" shown in FIGS.
Min. That is, the structure is such that the backward emission light of only the second light emitting element on the shorter resonator length side is selectively detected and monitored, and the output monitoring element is not provided behind the first light emitting element having the longer resonator length. As a result, the size of the device (light emitting element mounting body) can be reduced. At this time, the selective optical path branching element does not generate a new occupied area if the surface of the optical path conversion reflective element originally required as a light emitting element mounting body is used. Then, by arranging the sub-substrate and the reflective element on the same plane on the main substrate and fixing them together with an adhesive or the like, a compact integrated light-emitting element package can be configured.

Further, since the first output monitoring element is disposed on the surface of the main substrate and the second output monitoring element is disposed on the surface of the sub substrate, the first and second output monitoring elements can be electrically independent from each other. Since there is no restriction on the setting of the polarity relationship of the light emitting elements, circuit design is facilitated. In particular, if the first light emitting element is a short-wavelength side semiconductor laser for DVD, the output of the first light emitting element can be monitored by the forward emission light, so that the characteristic deterioration of the first light emitting element at a high temperature is compensated. Therefore, it is easy to increase the reflectance of the rear end face.

As described above, according to the light emitting element mounting body according to the first aspect of the present invention, the outputs of the plurality of light emitting elements having different resonator lengths arranged in parallel and close to each other can be independently controlled without mutual interference. , Can be detected with high accuracy. Further, the light emitting element mounting body according to the first feature of the present invention can be downsized, so that an optical system such as an optical pickup optical system can be downsized.
Simplification and cost reduction can be realized.

Specifically, for example, the oscillation wavelengths of the first and second light emitting elements are set to be different, and the selective optical path branching element is a wavelength-selective reflection film having a different reflectance depending on the wavelength. What should I do? For example, using a dielectric multilayer film or the like, the design is such that only part of the forward output light of the first light emitting element is transmitted, and the transmitted light is monitored by the first output monitoring element, The output of the light emitting element can be controlled.

Alternatively, in the first aspect of the present invention, the polarizations of light emitted from the first and second light emitting elements are orthogonal to each other,
The selective optical path branching element may be a polarization-dependent reflection film having a reflectance different depending on the polarization. For example, when the output light of the first light emitting element is a P-wave and the output light of the second light-emitting element is an S-wave, a polarization beam splitter (PBS) having a different reflectance between the P-wave and the S-wave may be used. A selective optical path branching element may be used. Specifically, if a selective optical path branching element having a reflectance of S wave of 100%, a reflectance of P wave of 80%, and a transmittance of 20% is used, the first light emitting element can be used as the first output monitoring element. Only the forward output light of the first light-emitting element arrives, and the output of the first light-emitting element can be controlled.

A second feature of the present invention is an optical system in which an optical element and a diffracted light receiving area for receiving diffracted light diffracted by the optical element are further incorporated into the light emitting element mounted body of the first feature. That is the gist. Here, the “optical element” is a selective type optical path branching element, the light emitted forward of the first and second light emitting elements whose optical path has been changed in the first direction is transmitted, and the light emitted forward is emitted from the object. The reflected light is transmitted again and diffracted.

As described in the light emitting element mounting body of the first feature, the resonator length of the second light emitting element is made shorter than the resonator length of the first light emitting element, and the first and second light emitting elements are formed. If the front end faces of the elements are aligned so that they are substantially coplanar,
Since it is not necessary to dispose an output monitoring element behind the first light emitting element having a long resonator length, the size can be reduced. At this time, since the selective optical path branching element may use the surface of the optical path conversion reflective element which is originally required as an optical system, no new occupied area is generated. Then, by arranging the sub-substrate and the reflective element on the same plane on the main substrate and fixing them together with an adhesive or the like, a compact optical system can be configured. As a result, downsizing, simplification, and cost reduction of an optical system such as an optical pickup optical system can be realized.

Further, since the first output monitoring element is arranged on the surface of the main board and the second output monitoring element is arranged on the surface of the sub-board, the first and second output monitoring elements can be electrically independent from each other. Since there is no restriction on the setting of the polarities of the light emitting elements, the circuit design of the optical system is facilitated. In particular, if a short wavelength side semiconductor laser for DVD is used as the first light emitting element,
Since the output of the light emitting element can be monitored by the forward emission light, it is also easy to increase the reflectance of the rear end face to compensate for the characteristic deterioration of the first light emitting element at a high temperature.

As described above, according to the optical system according to the second aspect of the present invention, the outputs of a plurality of light emitting elements having different resonator lengths arranged in parallel and close to each other can be independently and accurately output without interference. It can be detected well. Further, since the optical system according to the second aspect of the present invention can be downsized, a thin optical disk drive or the like can be realized.

In the optical system according to the second aspect of the present invention, the light reflected by the object again passes through the optical element and is diffracted. At that time, the non-diffracted light of the reflected light from the object reverses the incident light path (first direction) and reaches the selective optical path branching element again. If the light flux transmitted and refracted through the selective type optical path branching element again irradiates the light receiving area of the first output monitoring element, the output of the first light emitting element cannot be accurately monitored. However, the remaining part of the reflected light that travels backward as reflected light and reaches the selective optical path branching element again passes through the selective optical path branching element, but the transmitted light is refracted by Snell's law. If the difference in the refraction direction according to Snell's law is used, the light receiving area of the first output monitoring element provided on the surface of the main substrate goes backwards as reflected light of the first direction emitted light by the object, It can be installed again avoiding the irradiation area of the light beam transmitted and refracted through the selective optical path branching element.

Alternatively, in the second aspect of the present invention, a polarization control means is further provided in a part of the optical path in the first direction, wherein the selective type optical path branching element has polarization dependence of the reflectance, and the first light emitting element When the reflected light reflected from the object from the light emitted from the target reaches the selective optical path branching element again, substantially all the reflected light from the first light emitting element may be reflected. The undiffracted light of the reflected light from the object of the emitted light in the first direction travels backward in the incident light path, is rotated in polarization by the polarization control means, and reaches the selective optical path branching element again. But,
The reflected light that has reversed the first direction and reached the selective type optical path branching element has its polarization rotated by the polarization control means.
Almost all are reflected by the selective type optical path branching element,
To return to the direction of the light emitting element. For this reason,
Of the reflected light that travels backward as reflected light and reaches the selective optical path branching element again, components that pass through the selective optical path branching element can be almost ignored. In this way, if the polarization control means is configured to rotate the polarized light, it is possible to avoid the influence of the undiffracted light in the reflected light traveling backward in the optical path, and to accurately monitor the output of the first light emitting element. . As the "polarization control means" of the present invention, a "wave plate" or a "polarization rotating element" can be used. For example, if a quarter-wave plate is used, linearly polarized light can be converted into circularly polarized light, and further, polarization can be controlled so that the returned circularly polarized light after reflection by the object becomes linearly polarized light in the orthogonal direction. 1
Polarization control using a 波長 wavelength plate can be realized easily and at low cost, and is widely used. Further, a polarization rotating element such as a Faraday rotator that rotates with linearly polarized light may be used, but the polarization rotating element is generally expensive.

[0035]

Next, first and second embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic,
It should be noted that the relationship between the thickness and the plane dimension, the ratio of the thickness of each layer, and the like are different from actual ones. Therefore,
Specific thicknesses and dimensions should be determined in consideration of the following description. Further, it is needless to say that dimensional relationships and ratios are different between the drawings.

(First Embodiment) FIG. 1 shows an optical system (DVD / CD-R) according to a first embodiment of the present invention.
It is a perspective view which shows the light emitting element mounting body (semiconductor laser assembly) used for a compatible system. The first light-emitting element 1 and the second light-emitting element 2 are mounted on the surface of a submount (sub-substrate) 7 made of a silicon (Si) chip, and the second output monitoring element 4 is mounted on the submount 7. A light receiving area is formed. First light emitting element 1 and second light emitting element 2
As such, a semiconductor laser is preferable. Then, the resonator length of the second light emitting element 2 is shorter than the resonator length of the first light emitting element 1, and each light beam reciprocating in the resonators of the first light emitting element 1 and the second light emitting element 2. The axes are substantially parallel to each other, and the first light emitting element 1 and the second light emitting element 2 are arranged such that the front end faces thereof are located on substantially the same plane. For example, the resonator length of the first light emitting element 1 is 400 to
It is about 650 μm. On the other hand, the resonator length of the second light emitting element 2 is about 250 μm. Second output monitoring element 4
Are formed by selective diffusion on the surface of a submount 7 made of a Si chip, and a pn junction photodiode is formed between the light receiving region and the submount 7. The light receiving area of the second output monitoring element 4 is located so as to be limited to an area in front of an extension of the rear end face of the first light emitting element. By arranging the light receiving region of the second output monitoring element 4 at this position, the light emitted from the first light emitting element 1 is emitted from the first light emitting element 1 with respect to the second output monitoring element 4. Since the light is blocked by the rear end face, it is impossible to enter. The rear emission light of the second light emitting element 2 is well detected by the second output monitoring element 4 in a region including the vicinity of the rear light emitting point _{P2b where} the intensity is strongest, although the area is reduced.

The submount 7 is mounted on an upper surface of a main substrate (main mount) 14 made of a Si chip with a predetermined positional relationship together with a wedge-shaped reflecting element (optical path conversion mirror) 15 made of a transparent optical medium. A light receiving area of the first output monitoring element 3 is formed above the main substrate 14 below the reflection element (optical path conversion mirror) 15. Further, a plurality of diffracted light receiving areas 51 and 5 are provided above the main substrate 14.
2, 53, 54 are formed. These light receiving regions 3, 51, 52, 53 and 54 are formed by selective diffusion on the surface of a main mount 14 made of a Si chip, and constitute a pn junction photodiode with the main mount 14. In particular, the diffracted light receiving areas 51, 52, 53, 5
Reference numeral 4 denotes a photodiode array including a plurality of photodiodes.

The reflecting element 15 for optical path conversion shown in FIG.
It has a wedge shape with a 45 degree inclined surface. The 45-degree inclined surface is set so as to reduce the reflectance only at the emission wavelength λ1 of the _first light-emitting element 1 (in this case, only around 650 nm) and transmit light at a fixed ratio. The wavelength-selective reflection film 9 is provided. Wavelength selective reflection film 9
Function as the selective optical path branching element of the present invention. For example, this reflectance is 80% for an emission wavelength of 650 nm.
Should be set to. On the other hand, the reflectance of the wavelength-selective reflection film 9 is the emission wavelength λ _{2 of the} second light-emitting element ₂ , for example, 780 n
m is set to 98% or more. It is well known to those skilled in the art that the reflectance of the wavelength-selective reflection film 9 can be set almost freely by the thickness and the refractive index of the dielectric multilayer film. More specifically, a high-refractive-index dielectric film and a low-refractive-index dielectric film are alternately stacked at an optical film thickness nd (refractive index n × film thickness d) of 発 光 of the emission wavelength λ to select a wavelength. The reflective film 9 can be formed. For example, as the high refractive index dielectric film, zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ),
Tantalum oxide (Ta ₂ O ₅ ), niobium oxide (Nb
₂ O ₅ ), hafnium oxide (HfO ₂ ), cerium oxide (CeO ₂ ), or a mixture thereof. As the low refractive index dielectric film, silicon oxide (Si
O ₂ ), magnesium fluoride (MgF ₂ ), aluminum fluoride (AlF ₃ ), etc., or a mixture thereof can be used.

The wavelength-selective reflection film 9 is formed by the reflection element 15
1, the transmitted light composed of a part (20%) of the output light (emission wavelength λ ₁ = 650 nm) of the _first light emitting element 1 is indicated by a broken line in FIG. The reflective element 15 is refracted on this surface in a second direction as shown and at a predetermined angle.
, That is, the surface of the light receiving area of the first output monitoring element 3 provided on the main substrate 14 at an angle. The reflected light composed of the remainder (80%) of the output light of the first light emitting element 1 is reflected on this surface in the first direction shown by the solid line in FIG. That is, the optical path is changed in a direction perpendicular to the surface of the main mount 14.

FIG. 2 is a top view corresponding to the semiconductor laser assembly (DVD / CD-R compatible two-wavelength device) shown in the perspective view of FIG. The reflected light composed of 80% of the output light of the first light emitting element 1 shown by the solid line in FIG. 2 is subjected to the optical path conversion by the wavelength-selective reflection film 9 in a direction perpendicular to the paper surface (not shown). Most (98% or more) of the output light (emission wavelength λ ₂ = 780 nm) of the _second light-emitting element 2 shown by the solid line is reflected by the wavelength-selective reflective film 9 in the direction perpendicular to the plane of the paper, and is perpendicular to the plane of the paper. The optical path is changed in the direction (not shown). On the other hand, the transmitted light composed of 20% of the output light of the first light emitting element 1 shown by the broken line in FIG. Are obliquely incident on the surface of the light receiving area of the first output monitoring element 3 provided on the main substrate (main mount) 14.

As described above, in the light emitting device mounted body (semiconductor laser assembly) according to the first embodiment of the present invention, the output monitor of the first light emitting device 1 is provided on the upper portion near the surface of the main substrate 14. By providing the light receiving area of the first output monitoring element 3, the light output of the first light emitting element 1 can be detected well.

As shown in FIG. 2, after the second light emitting element 2
Receiving area of the second output monitoring element 4 for receiving the light emission output
Is the rear light emitting point P of the second light emitting element 2_2bThe neighborhood of
It is located only in the place. This particular location is the first
Rear light emitting point P of light emitting element 1 _1bThe vertex of the sector
1 radiation angle range 5 (see FIG. 7) and the second light emitting element
Rear emission point P_2bThe second radial angle range of the fan shape whose peak is
A region where the enclosure 6 does not overlap, that is, a radiation angle overlapping region 77
(See FIG. 7). Second output
The specific place for arranging the light receiving area of the monitoring element 4 is
Limited to the area in front of the extension of the rear end face of the light-emitting element 1
Is located as defined. In this case, the second output
The output light of the first light-emitting element 1 is
1 light emitting element 1 itself is cut off by the rear end face.
It becomes impossible to enter. And a second light emitting element
The backward emission light of No. 2 has the highest intensity, although the area is reduced.
Strong rear emission point P_2bMonitor the second output in the area including the neighborhood
Good detection by element 4.

As described above, according to the light emitting device mounted body (semiconductor laser assembly) according to the first embodiment of the present invention, a plurality of light emitting devices 1 and 2 having different resonator lengths are arranged in parallel and close proximity. The output can be detected independently and accurately without mutual interference. That is, the backward emission lights of the first light emitting element 1 and the second light emitting element 2 are optically well separated from each other by their positional relationship, and the forward emission lights of the first light emitting element 1 and the second light emitting element 2 are provided. Are optically satisfactorily separated from each other by the wavelength dependence of the reflectance of the wavelength-selective reflection film 9 of the reflection element 15.

In the semiconductor laser assembly according to the first embodiment of the present invention, the area of the first output monitoring element 3 in the structure of the previously proposed semiconductor laser assembly shown in FIGS. This corresponds to the deleted structure. First
1 and 2, the outer dimensions of the semiconductor laser assembly are reduced by the length "L" as shown in FIGS. Specifically, the length L =
The outer dimensions of the semiconductor laser assembly can be reduced by about 0.2 to 0.4 mm. Although the second output monitoring element 4 is present, the dimension required for this area is within the minimum dimension determined by the resonator length of the first light emitting element 1 and does not contribute to the external dimensions. Can be significantly reduced in size.

FIG. 3A is a sectional view taken along the line AA of FIG. As shown in FIG. 3A, a sub-substrate (submount) 7 made of a Si chip is bonded to an upper surface of a main substrate (main mount) 14 made of a Si chip via a conductive adhesive 128 or solder. I have. Also, Si
A transparent adhesive 136 is provided on the upper surface of the main substrate 14 composed of chips.
, A wedge-shaped reflecting element (optical path conversion mirror) 15 made of a transparent optical medium such as glass is joined. That is,
The main substrate 14, the sub-substrate 7, and the reflection element 15 are integrally formed. The light receiving area 141 of the first output monitoring element 3 is provided on the surface of the main board 14, and the light receiving area of the second output monitoring element 4 is provided on the surface of the sub board 7.

FIG. 3B is an enlarged view showing the vicinity of the light receiving region 141 of the first output monitoring element 3 shown in FIG. 3A in detail. As shown in FIG. 3B, the photodiode 3 constituting the first output monitoring element 3 has a substrate thickness of 250 μm.
a semiconductor substrate (hereinafter, referred to as an “n substrate”) 140 made of n-type Si of m to 450 μm;
The anode region (light receiving region) 141 formed of a p-type semiconductor region having a higher impurity density than the n substrate 140 formed on the front surface of the n substrate 140 and the entire back surface of the n substrate 140 facing the anode region 141. A common cathode region 142 made of an n-type semiconductor region having a higher impurity density than the formed n-substrate 140 is provided. The impurity density of the anode region 141 and the common cathode region 142 is, for example, 3 × 10 ¹⁸ c
m ^{−3 to} 5 × 10 ¹⁹ cm ⁻³ . In the photodiode 3, the n-substrate 140 sandwiched between the anode region 141 and the common cathode region 142 functions as a cathode drift region. Cathode drift region 14
The impurity density of 0 is, for example, 5 × 10 ¹² cm ^{−3 to} 5 × 1
It is preferable to use an intrinsic (i-type) semiconductor region of about 0 ¹⁵ cm ⁻³ . By making the cathode drift region 140 i-type, a pin photodiode can be configured, and high-sensitivity light detection becomes possible. Further, the anode wirings 1 formed on the front side and the back side of the n-substrate 140, respectively.
35, and a common cathode electrode 143. Although not shown in FIG. 3, a plurality of diffracted light receiving regions 5
1, 52, 53, and 54 also constitute a pin photodiode by the p-type semiconductor region and the n-substrate 140 formed by the same selective diffusion.

As shown in FIG. 3B, the n-substrate 140
On the surface, field oxidation formed by thermal oxidation etc.
The film 139 is formed to a thickness of about 350 nm to 1 μm.
I have. Then, provided on this field oxide film 139
The surface of the n-substrate 140 located at the opening (window)
The load region 141 is provided. Field oxide film 1
On the surface of the anode region 141 exposed to the window at 39,
A window oxide film 138 having a thickness of 50 nm to 150 nm is provided.
Have been. On top of this window oxide film 138, a thickness of 60
nm to 200 nm silicon nitride film (Si_ThreeN_FourMembrane) 1
37 are arranged. Nitride film 137 and window oxide film 1
Through a contact hole penetrating through the nitride film 13
0.5 mm to 2 μm thick aluminum extending the surface of 7
Wiring 135 made of a metal film such as aluminum (Al)
Are in ohmic contact with the anode region 141. window
Partial oxide film (low refractive index material thin film) 138 and nitride film
137 constitutes an anti-reflection film.
That is, a low-refractive-index material thin film and a medium-high-refractive-index material thin film are laminated.
The anti-reflection effect by utilizing the optical interference effect.
The fruits are improving. Nitride film (medium-high refractive index material thin film) 1
37 is omitted, and a single-layer antireflection film only of the window oxide film 138 is provided.
It is also possible to configure a stop film. The window oxide film 13
8 instead of Magnesium fluoride, which has a lower refractive index than Si
Um (MgF_Two), Calcium fluoride (CaF_Two),
Lithium nitride (LiF ), Aluminum fluoride (Al
F_Three ) Can be used. Change
Instead of the nitride film 137, cerium oxide (CeO
_Two ), Aluminum oxide (Al_TwoO _Three ), Zirconium oxide
Um (ZrO_Two), Titanium oxide (TiO)_Two ), Tan oxide
Tal (Ta_TwoO_Five ) Can be used.
It is. Then, the nitride film 137 and the bottom of the reflection element 15 are formed.
, A transparent adhesive is inserted, and the reflective element 15 is
Upper surface of main substrate (main mount) 14 made of i-chip
It is fixed as one.

Although illustration of the detailed structure is omitted, the second
The output monitoring element 4 has the same structure as the first output monitoring element 3. That is, the photodiode constituting the second output monitoring element 4 uses an n-substrate (i-type substrate) having a substrate thickness of 250 μm to 450 μm as the sub-substrate 7, and a p-type substrate formed on the surface side of the sub-substrate 7. An anode region (light receiving region) composed of a semiconductor region and a sub-substrate 7 facing the anode region
Having a cathode region formed of an n-type semiconductor region having a higher impurity density than the sub-substrate 7 formed on the entire back surface of
In photodiode. An antireflection film is formed on the surface of the anode region as in FIG. Furthermore,
An anode wiring is formed on the front side of the sub-substrate 7 through a contact hole similar to that shown in FIG. 3B, and a cathode electrode is provided on the back side of the sub-substrate 7. The cathode electrode of the photodiode constituting the second output monitoring element 4 is connected to the cathode electrode wiring formed on the surface of the nitride film 137 shown in FIG. .

In the semiconductor laser assembly according to the first embodiment of the present invention, the first output monitoring element 3 is disposed on the main board 14 and the second output monitoring element 4 is
Although these are integrally fixed, the interface is provided with a field oxide film 139 and a window oxide film 13.
8 and the insulating layer composed of the nitride film 137 are formed so that they are electrically separated well. In the output control (APC) of the semiconductor laser, the p and n polarities of both the semiconductor laser and the monitor may be set to a plurality of common (common) relations in accordance with a request from the circuit side. Since they are separated, there is no restriction on the setting of the polarity relationship between the two semiconductor lasers.

FIG. 4 is a perspective view showing an optical system (DVD / CD-R compatible system) according to the first embodiment of the present invention. A main substrate 14 is arranged in a predetermined positional relationship with respect to an optical element 16 on which a hologram having light diffraction and lens action is formed. The optical element 16 is arranged in a predetermined positional relationship with respect to an optical disk (not shown). DVDs and CD-Rs are used interchangeably as optical disks. DVDs and CD-Rs each have a track on which information is recorded on its surface. D
The read position of the track of the VD has the optical axis of the reflected light R _R1 from a disk, there is an optical axis of the reflected light R _R2 from the disk to read the position of the tracks of the CD-R. The optical axis of the optical axis and the reflected light R _R2 of the reflected light R _R1 is present on a common optical axis. At the center of the optical element 16, a circular hologram is formed centering on a point through which the optical axis passes, and this hologram is divided into first and second holograms in a direction coinciding with the tangential direction by dividing lines intersecting the optical axis. Area.

The main substrate 14 receives four diffracted light beams for receiving the luminous flux of ± 1st-order diffracted light diffracted by the first region of the hologram and the ± 1st-order diffracted light beam diffracted by the second region. The areas 51, 52, 53, 54 are formed in a positional relationship as shown in the figure.

An objective lens (not shown) is arranged between the optical disk (DVD or CD-R) and the optical element 16. A housing (package) 17 is arranged in a predetermined positional relationship with respect to the optical element 16, and Si
A main substrate 14 made of a chip is stored. Main board 1
4, a diffracted light receiving area 51, 52, 53, 54 is provided, and a sub-substrate (sub-mount) 7 made of a Si chip is arranged in the center thereof. The first light emitting element 1 and the second light emitting element 2 are arranged on the sub-substrate 7, and a wedge-shaped reflecting element 15 made of a transparent optical medium is arranged so as to face the sub-substrate 7. The reflection element 15 has a wedge shape having a 45-degree inclined surface, and the wavelength-selective reflecting film 9 is provided on the 45-degree inclined surface. A light receiving area of the first output monitoring element 3 is formed above the main substrate 14 below the reflecting element 15. Behind the second light emitting element 2 on the sub-substrate 7, the second output monitoring element 4
Are formed. Further, the objective lens, the optical element 16, the housing 17, and the like are housed integrally in the optical pickup housing. In this case, the hologram element 16 can be used as a transparent window and a hermetically sealed window of the housing 17. Alternatively, the optical element (hologram element) 16 is
It can also be used as a transparent window and a hermetically sealed window of an optical pickup housing including the housing (package) 17.

Outgoing light R emitted from the first light emitting element 1
80% of _i1 is the wavelength-selective reflective film 9 of the reflective element 15.
, The path is changed at a right angle, and the light is irradiated in the first direction toward the optical element 16, and the optical axis thereof coincides with the optical axis of the reflected light _RR1 . 20% of the emitted light R _i1 emitted from the first light emitting element 1 passes through the wavelength-selective reflecting film 9 of the reflecting element 15, is refracted by Snell's law, proceeds in the second direction, and travels in the second direction. The light receiving area of the output monitoring element 3 is irradiated. The light traveling in the first direction and entering the hologram of the optical element 16 is further converged by the objective lens and
Focus on one point on the surface of VD). Optical disk (DV
D) The light condensed on is modulated in accordance with the recorded information of the track, and is reflected in the same path (first direction) as that at the time of incidence. The reflected light R _R1 passes through an optical system such as unillustrated objective lens, a first direction GyakuMuko, the optical element 1
The hologram No. 6 is incident. Similarly, the second light emitting element 2
98% or more of the outgoing light _Ri2 emitted from the optical element 16 has its course changed at a right angle by the wavelength-selective reflective film 9 of the reflective element 15, travels in the first direction toward the optical element 16, and its optical axis is reflected. coincides with the optical axis of the optical R _R2. The light traveling in the first direction and incident on the hologram of the optical element 16 is further converged by the objective lens and condensed on one point on the surface of the optical disk (CD-R). The light condensed on the optical disk (CD-R) is modulated in accordance with the recorded information of the track, and is reflected in the same path (first direction) as that at the time of incidence. The reflected light R _R2 passes through an optical system such as an objective lens (not shown), and reverses the first direction, and enters the hologram of the optical element 16.

Since the hologram is divided into a first area and a second area, the reflected lights R _R1 and R _R2 are diffracted by the first area to become luminous fluxes of ± 1st-order diffracted light, which is the main substrate 1.
4 are incident on the diffracted light receiving areas 51 and 53, and the reflected light _RR1 and _RR2 are diffracted in the second area into ± 1st order diffracted light beams, which are the diffracted light receiving areas 52 and 53 on the main substrate 14.
It is incident on 54. Diffracted light receiving areas 51, 52, 53,
Numeral 54 is divided into four parts by using the first straight line and the second straight line as a center dividing line, and a combination of the two makes it possible to obtain a two-part photoelectric conversion region and a three-part photoelectric conversion region simultaneously. Then, the diffracted light receiving areas 51 and 5
By calculating the photoelectric conversion signals obtained from 2, 53, 54, an information signal recorded on DVD or CD-R can be obtained. That is, the plurality of diffracted light receiving areas 5
1, 52, 53, and 54, a reproduction signal is obtained, and predetermined arithmetic processing between the divided regions is performed by an electronic circuit (not shown) connected to these diffracted light receiving regions 51, 52, 53, and 54. It is also possible to obtain an error signal such as focus and tracking for each of the DVD and CD-R by executing the process.

FIGS. 1 and 2 show that the outer dimensions of the semiconductor laser assembly are reduced by the length "L". This is equivalent to reducing the width “D” of the housing 17 shown in FIG. In an actual optical pickup, the housing 17 is used in an orientation rotated by 90 ° with respect to FIG. 4, and determines the width “D” thickness (height) of the housing 17. Therefore, the fact that the height “D” of the housing 17 can be reduced greatly contributes to the realization of a thin optical disk drive or the like. In general, in an actual optical pickup, the height D is about 3 mm, so that the length L
To be able to reduce the thickness by about 0.2 to 0.4 mm means that it is possible to further reduce the thickness.

DVD of upward (first direction) emitted light R _i1
The non-diffracted light of the reflected light _RR1 by the light travels backward in the incident light path and reaches the wavelength-selective reflection film 9 of the reflection element 15 again. If the light flux transmitted and refracted through the wavelength-selective reflection film 9 irradiates the light receiving region 141 of the first output monitoring element 3 again, the output of the first light emitting element 1 cannot be accurately monitored. That is, as shown in FIG. 5, 80% of the outgoing light R _i1 emitted from the first light emitting element 1 is reflected by the wavelength-selective reflective film 9 of the reflecting element 15 and radiates toward the upper optical element 16. Is done. However, 20% of the emitted light R _i1 emitted from the first light-emitting element 1 passes through the wavelength-selective reflection film 9 of the reflection element 15 and is refracted by Snell's law to be refracted by the first output monitoring element 3. The light receiving area 141 is irradiated, and the output of the first light emitting element 1 is monitored. The upward emission light R _{i1 that} has entered the hologram of the optical element 16 is focused on one point on the surface of the DVD. Light reflected on the DVD returns along the incident optical path (first direction). The reflected light R _R1 again enters the hologram of the optical element 16, but the undiffracted light _returns as reflected light R _R1 in the incident light path (first direction) again, and again the wavelength-selective reflection film of the reflection element 15. Reaches 9. Then, 80% of the reflected light _{RR 1} is reflected by the wavelength-selective reflective film 9 and
Return to the direction of the light emitting element 1. On the other hand, 20% of the reflected light R reflected light led to the wavelength selective reflection film 9 again reflecting element 15 retrograde as _R1 R _R1 is transmitted through the wavelength-selective reflection film 9. The light transmitted through the wavelength-selective reflection film 9 is refracted according to Snell's law. Figure 5 is a first light receiving region 141 of the output monitoring device 3 provided on the surface of the main substrate 14, retrograde as reflected light R _R1 by the DVD of the top emission light R _i1,
It is shown that it is installed again avoiding the irradiation area of the light flux transmitted and refracted through the wavelength-selective reflection film 9 of the reflection element 15.

As shown in FIG. 5, the first output monitoring element 3
By selecting the position of the light receiving region 141, the influence of the undiffracted light in the reflected light _RR1 can be avoided, and the output of the first light emitting element 1 can be accurately monitored.

As described above, according to the optical system according to the first embodiment of the present invention, the outputs of a plurality of light-emitting elements (semiconductor lasers) having different resonator lengths arranged in parallel and close proximity are determined.
Detection can be performed independently and accurately without mutual interference. Further, the size of the integrated device and the optical pickup can be reduced, and a thin optical disk drive can be realized.

(Second Embodiment) FIG. 6 shows an optical system (DVD / CD-R) according to a second embodiment of the present invention.
(Compatible system). A main substrate 14 is arranged in a predetermined positional relationship with respect to an optical element 16 on which a hologram having light diffraction and lens action is formed.
On the upper part of the optical element 16, 1/4 as polarization control means 26 is provided.
The wave plate is fixed with a transparent adhesive. It is easy to make the quarter-wave plate 26 wavelength-selective, or it may be a magnetic rotatory element by the Faraday effect.

As in the first embodiment, the luminous flux of the ± 1st-order diffracted light diffracted by the first area of the hologram and the ± 1st-order diffracted light diffracted by the second area are provided on the main substrate 14. Four diffracted light receiving areas 51, 52, which receive light beams,
53 and 54 are formed in a positional relationship as shown in the figure. Further, an objective lens (not shown) is arranged between the optical disk (DVD or CD-R) and the quarter-wave plate 26. In addition, the housing 17 has a predetermined positional relationship with respect to the optical element 16.
The main board 14 made of a Si chip is housed in the housing 17. The main substrate 14 is provided with diffracted light receiving regions 51, 52, 53, and 54, and the sub-substrate 7 made of a Si chip is disposed at the center thereof. The first light emitting element 1 and the second light emitting element 2 are arranged on the sub-substrate 7, and a wedge-shaped reflecting element 15 made of a transparent optical medium is arranged so as to face the sub-substrate 7. As the first light emitting element 1 and the second light emitting element 2, a semiconductor laser is suitable as in the first embodiment. The reflection element 15 has a wedge shape having a 45-degree inclined surface.
A polarization-dependent wavelength-selective reflection film 99 is provided on the 5-degree inclined surface. The polarization-dependent wavelength-selective reflection film 99 functions as the selective optical path branching element of the present invention. As the polarization-dependent wavelength-selective reflection film 99, a polarization beam splitter (PB
S) can be used. A light receiving area of the first output monitoring element 3 is formed above the main substrate 14 below the reflecting element 15. Behind the second light emitting element 2 on the sub-substrate 7, a light receiving area of the second output monitoring element 4 is formed. Further, the objective lens, the optical element 16, the quarter-wave plate 26, the housing 17, and the like are integrally housed in the optical pickup housing.

The emitted light R emitted from the first light emitting element 1
80% of _i1 has its course changed at right angles by the polarization-dependent wavelength-selective reflective film 99 of the reflective element 15, and the optical element 16
Irradiates in the first direction toward
Rotates the polarization. 20% of the emitted light R _i1 emitted from the first light emitting element 1 passes through the polarization dependent wavelength selective reflection film 99 of the reflection element 15 and is refracted by Snell's law (branched in the second direction). ), First output monitoring element 3
Is irradiated on the light receiving area. The light traveling in the first direction and having its polarization rotated by the quarter-wave plate 26 is further converged by the objective lens and condensed on one point on the surface of the DVD. DV
The light condensed on D is modulated according to the recorded information on the track, and reflects (reverses) on the same path (first direction) as when the light was incident. The reflected light R _R1 passes through an optical system such as an objective lens, and is again incident on the hologram of the optical element 16 after its polarization is rotated by the 波長 wavelength plate 26 again. Similarly, 98% or more of the outgoing light R _i2 emitted from the second light emitting element 2 has its course changed at a right angle by the polarization dependent wavelength selective reflection film 99 of the reflection element 15 and proceeds in the first direction. The polarization is further rotated by the quarter-wave plate 26. 1
The light whose polarization has been rotated by the 波長 wavelength plate 26 is further converged by the objective lens and condensed at one point on the surface of the CD-R. The light condensed on the CD-R is modulated according to the recorded information of the track, and is reflected through the same path as when the light was incident. The reflected light _RR2 passes through an optical system such as an objective lens, and its polarization is rotated by the quarter-wave plate 26, and enters the hologram of the optical element 16.

The reflected light R of the upward emitted light R _i1 by DVD
The non-diffracted light in _R1 reverses the incident light path (first direction), the polarization is rotated by the 波長 wavelength plate 26, and reaches the polarization dependent wavelength selective reflection film 99 of the reflection element 15 again. However, retrograde incident optical path (a first direction), the reflected light R _R1 that led to the polarization-dependent wavelength-selective reflecting film 99, since the rotation of the polarized light by 1/4-wavelength plate 26, polarization dependent wavelength selection 98% or more is reflected by the reflective film 99 and returns to the first light emitting element 1. Therefore, component transmitted through the polarization-dependent wavelength-selective reflection film 99 of the polarization dependent wavelength-selective reflection film 99 reflecting light R _R1 that led to the reflected light R _R1 reflecting element 15 again retrograde as most negligible . Thus, 1/4 if configured to rotate the polarization by the wavelength plate 26, can avoid the influence of non-diffracted light of the reflected light R _R1 coming retrograde optical path, correct the first light emitting element 1 output monitor.

Except for using the polarization-dependent wavelength-selective reflection film 99, the light-emitting element mounting body used in the optical system according to the second embodiment of the present invention is basically the same as that of the first embodiment. And the duplicated description will be omitted.

As described above, according to the optical system according to the second embodiment of the present invention, the outputs of a plurality of light emitting elements (semiconductor lasers) having different resonator lengths arranged in parallel and close proximity to each other are
Detection can be performed independently and accurately without mutual interference. Further, the reflected light R traveling backward in the optical path (first direction)
Of the first light emitting element 1 can be accurately monitored. As a result, the size of the integrated device and the optical pickup can be reduced, and a thin optical disk drive can be realized.

The polarization control means (1/4 wavelength plate) 26
Is not limited to the upper part of the optical element 16 shown in FIG. The polarization control means (１ ／ wavelength plate) 26 may be arranged between the optical element 16 and the polarization dependent wavelength selective reflection film 99 of the reflection element 15. Alternatively, it may be arranged between an optical disk (DVD or CD-R) not shown and the objective lens.

(Other Embodiments) As described above, the present invention has been described with reference to the first and second embodiments.
The discussion and drawings that form part of this disclosure should not be understood as limiting the invention. From this disclosure, various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art.

In the description of the first and second embodiments, the wavelength-selective reflection film 9 and the polarization-dependent wavelength-selective reflection film 99 have been described as selective optical path branching elements. A polarization-dependent reflection film that selects the polarization of the light emitting element 1 and the second light emitting element 2 and branches only the light flux of the first light emitting element 1 may be used. For example, when the output light of the first light emitting element 1 is a P wave and the output light of the second light emitting element 2 is an S wave, a polarizing beam splitter (PBS) having different reflectances for the P wave and the S wave is used. What is necessary is just to provide on the 45-degree inclined surface of the reflection element 15 as a polarization dependent reflection film for optical path conversion. For example, if a PBS having a reflectance of 100% for the S wave, a reflectance of 80% for the P wave, and a transmittance of 20% is used, the first output in the configuration similar to the configuration shown in FIGS. Only the output light of the first light emitting element 1 reaches the light receiving area of the monitoring element 3 and can be monitored.

In the description of the first and second embodiments, a main substrate (main mount) made of a Si chip is used.
14 and the sub-substrate (submount) 7 have been described, but a compound semiconductor such as gallium arsenide (GaAs) is used for the main substrate 1.
4 and the sub-substrate 7. If a GaAs substrate is used, a photodiode with higher sensitivity can be configured as the first output monitoring element 3 and the second output monitoring element 4.

As described above, the present invention naturally includes various embodiments and the like not described herein. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention according to the claims that are appropriate from the above description.

[0070]

According to the light emitting element mounted body of the present invention, the outputs of a plurality of light emitting elements arranged in parallel and close proximity can be detected independently and accurately without mutual interference.

According to the light emitting element mounting body of the present invention, miniaturization is easy, and further miniaturization can realize miniaturization, simplification, and cost reduction of an optical system such as an optical pickup.

According to the optical system of the present invention, a thin optical disk drive can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a light emitting element mounted body used for an optical system according to a first embodiment of the present invention.

FIG. 2 is a top view corresponding to the light emitting element mounting body shown in the perspective view of FIG.

FIG. 3A is a cross-sectional view taken along the line AA of FIG. 2; FIG. 3B is a diagram showing the vicinity of a light receiving region of the first output monitoring element shown in FIG. 3A; FIG.

FIG. 4 is a perspective view showing an optical system according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of the optical system according to the first embodiment of the present invention, in which the light receiving area of the first output monitoring element goes backwards as reflected light of the upward emitted light by the DVD and transmits through the wavelength-selective reflecting film. It is sectional drawing which shows that it is installed avoiding the irradiation area | region of the refracted light beam.

FIG. 6 is a perspective view showing an optical system according to a second embodiment of the present invention.

FIG. 7 is a top view of the semiconductor laser assembly according to the previous proposal.

FIG. 8 is a perspective view showing an optical system according to the above proposal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st light emitting element 2 2nd light emitting element 3, 33 1st output monitoring element 4 2nd output monitoring element 5 1st radiation angle range 6 2nd radiation angle range 7 Submount (sub board) 8 Parting line 9 Wavelength selective reflection film (selective optical path branching element) 10 Rear end face 11 Optical path conversion element 14 Main substrate (main mount) 15 Reflection element (optical path conversion mirror) 16 Optical element (hologram element) 17 Housing (package) 19) Extension line of rear end face 26 Polarization control means (1/4 wavelength plate) 51, 52, 53, 54 Diffracted light receiving area 77 Emission angle overlapping area 99 Polarization dependent wavelength selective reflection film (selective optical path branching element) 128 conductive adhesive 135 anode wiring 136 transparent adhesive 137 silicon nitride film (Si ₃ N ₄ film) 138 window oxide film 139 field oxide film 140 n substrate (caso) Drift region) 141 anode region (light receiving region) 142 common cathode region 143 common cathode electrode C ₁ corner portion behind first light emitting element and on the side close to second light emitting element P _1f first light emitting element Front light emitting point P _2f front light emitting point of second light emitting element P _1b rear light emitting point of first light emitting element P _2b rear light emitting point of second light emitting element

Claims (5)

[Claims] 1. A main substrate made of a semiconductor chip, a sub substrate made of a semiconductor chip mounted on the main substrate, a first light emitting element mounted on the sub substrate, A second light emitting element which is disposed in proximity to the first light emitting element and whose output is controlled independently of the first light emitting element, and only an optical path of forward emission light of the first light emitting element A selective optical path branching element that branches in first and second directions, and converts an optical path of forward emission light of the second light emitting element to substantially the same direction as the first direction; A first output monitoring element having a light receiving area at a position in the second direction on the surface, and receiving a forward light emission output of the first light emitting element by the light receiving area; and a second output monitoring element on the surface of the sub-substrate. A light-receiving area in the vicinity of the rear light-emitting point of the light-emitting element, The second
And a second output monitoring element for receiving a rear emission output of the light emitting element. 2. The light-emitting device according to claim 1, wherein the first and second light-emitting elements have different oscillation wavelengths, and the selective optical path branching element is a wavelength-selective reflection film having a reflectance different depending on the wavelength. The light-emitting device mounted body according to the above. 3. The light emitted from the first and second light emitting elements has polarizations orthogonal to each other, and the selective optical path branching element is a polarization dependent reflection film having a reflectance different depending on the polarization. The light-emitting element package according to claim 1. 4. A main substrate made of a semiconductor chip, a sub substrate made of a semiconductor chip mounted on the main substrate, a first light emitting element mounted on the sub substrate, A second light emitting element which is disposed in proximity to the first light emitting element and whose output is controlled independently of the first light emitting element, and only an optical path of forward emission light of the first light emitting element A selective optical path branching element that branches in first and second directions, and converts an optical path of forward emission light of the second light emitting element to substantially the same direction as the first direction; A first output monitoring element having a light receiving area at a position in the second direction on the surface, and receiving a forward light emission output of the first light emitting element by the light receiving area; and a second output monitoring element on the surface of the sub-substrate. A light-receiving area at a position near the rear light-emitting point of the light-emitting element; A second output monitoring element for receiving a rear emission output of the second light emitting element by an optical region; and the first and second light emitting elements whose optical paths have been changed in the first direction by the selective light path branching element. And at least a diffracted light receiving region that receives the diffracted light diffracted by the optical element and transmits and diffracts the reflected light, which is reflected by the object and transmits the forward emitted light. An optical system, characterized in that: 5. The apparatus according to claim 1, further comprising: a polarization controller provided in a part of the optical path in the first direction, wherein the selective optical path branching element has a polarization dependence of a reflectance, and the emitted light from the first light emitting element is The method according to claim 4, wherein when the reflected light reflected by the object reaches the selective light path branching element again, substantially all of the reflected light from the first light emitting element is reflected. Optical system.