JP2001250254A - Optical apparatus and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical apparatus such as a laser coupler capable of obtaining stable output characteristics by constantly offsetting thermal characteristics for a light beam of an arbitrary wavelength, even in the case plural laser elements are monitored with a PD of the same characteristics; and also to provide an optical disk device using this apparatus. SOLUTION: Among the outgoing laser beams L1, L2 of plural laser diodes LD1, LD2, in one laser beam L1 (e.g. with a wavelength of 780 nm), the protective film 53 of the laser end face is provided with such a reflection characteristic as offsets the thermal characteristics of a PD for monitoring; and, in addition, an optical film 54, in which reflectivity for the other laser beam L2 (e.g. with a wavelength of 650 nm) increases at the time of rising temperature, is provided in the optical path between the plural laser diodes LD1, LD2 and the plural photodiodes 16, 17 and 18, 19, particularly on the spectral surface 20a of a prism 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device and an optical disk device, and more particularly, to a plurality of light emitting elements respectively emitting a plurality of different lights, which are arranged side by side in a direction intersecting a light emitting direction. The present invention relates to an optical device (in particular, an optical pickup) provided with a plurality of light receiving elements for receiving light, and an optical disk device for irradiating the plurality of lights to a disk-shaped information recording medium and reading information by reflected light.

[0002]

2. Description of the Related Art CD (Compact Disk), DVD
(Digital Video Disc) or MD (Mini Disc)
Read (reproduce) information recorded on an optical recording medium for optically recording and / or reproducing information (hereinafter, may be referred to as an optical disk), or write (record) information to or from them. (Hereinafter, may be referred to as an optical disk device) has a built-in optical pickup.

In such an optical disk device or optical pickup, laser beams having different wavelengths are generally used when the type of optical disk (optical disk system) is different. For example, a laser beam having a wavelength of 780 nm is used for reproducing a CD, and a laser beam having a wavelength of 650 nm is used for reproducing a DVD.

In such a situation where the wavelength of the laser beam differs depending on the type of the optical disk, a compatible optical pickup which enables reproduction of a CD by an optical disk device for a DVD, for example, is desired.

[0005] FIG. 14 shows a conventional laser diode LD1 (oscillation wavelength 780 nm) and a laser diode LD2 (oscillation wavelength 650 nm) for DVD, as described above, on which a CD and a DVD can be reproduced. FIG. 1 is a schematic configuration diagram of a compatible optical pickup 100.

The optical pickup 100 is, for example, 78
A first laser diode LD1, a grating G, a first beam splitter BS1, a first mirror M1, a first objective lens OL1, a first laser diode LD1, which emits a laser beam having a wavelength of 0 nm band.
Multi-lens ML1 and first photodiode PD1
Have a CD optical system individually (ie, discretely) disposed at predetermined positions.

Further, the optical pickup 100 has a second laser diode LD2, a second beam splitter BS2, a collimator C, a second mirror M2, a second objective lens OL2, which emits a laser beam having a wavelength in the 650 nm band, for example.
Second multi-lens ML2 and second photodiode P
D2 has DVD optical systems individually (ie, discretely) arranged at predetermined positions.

[0008] The optical pickup 10 thus configured
0, the first laser diode LD
The first laser light L1 from 1 passes through the grating G, is partially reflected by the first beam splitter BS1, bends the path by the first mirror M1, and is condensed on the optical disk D by the first objective lens OL1. Is done.

The reflected light from the optical disc D passes through the first multi-lens ML1 via the first objective lens OL1, the first mirror M1, and the first beam splitter BS1, and
The light is incident on the first photodiode PD1, and the information recorded on the CD recording surface of the optical disk D is read by the change in the reflected light.

Also in the DVD optical system of the optical pickup 100, the second laser beam L2 from the second laser diode LD2 is partially reflected by the second beam splitter BS2 and passes through the collimator C in the same manner as described above. Then, the path is bent by the second mirror M2, and the light is focused on the optical disk D by the second objective lens OL2.

The reflected light from the optical disk D is transmitted to the second objective lens OL2, the second mirror M2, the collimator C, and the second objective lens OL2.
Through the beam splitter BS2, the second multi-lens M
After passing through L2, it is incident on the second photodiode PD2, and the information recorded on the DVD recording surface of the optical disk D is read by the change of the reflected light.

According to the optical pickup 100, the CD
A laser diode for DVD and a laser diode for DVD are mounted, and the respective optical systems enable reproduction of CD and DVD.

FIG. 15 shows a laser diode LD1 for a CD (oscillation wavelength of 780 nm) and a DVD as described above.
Configuration diagram of another conventional compatible optical pickup 101 mounted with a laser diode LD2 (oscillation wavelength 650 nm) for reproducing CDs and DVDs.

The optical pickup 101 is, for example, 78
A first laser diode LD1, a grating G, a first beam splitter BS1, a dichroic beam splitter DBS, a collimator C, a mirror M, an aperture limiting aperture R for CD, an objective lens OL, a first multi, which emits a laser beam having a wavelength of 0 nm band. The lens ML1 and the first photodiode PD1 each have a CD optical system individually (ie, discretely) disposed at predetermined positions.

Further, the optical pickup 101 includes, for example, a second laser diode LD2, a second beam splitter BS2, a dichroic beam splitter DBS, a collimator C, which emits a laser beam having a wavelength in the 650 nm band.
Mirror M, objective lens OL, second multi-lens ML2,
And the second photodiode PD2 individually (ie, discretely) disposed at a predetermined position.
Optical system.

In each of these optical systems, some optical members are shared, for example, a dichroic beam splitter DBS, a collimator C, a mirror M, and an objective lens OL.
Is shared by both optical systems. Further, since the optical axis is shared between the dichroic beam splitter DBS and the optical disk D, the aperture limiting aperture R for CD is D
It is also arranged on the optical axis of the VD optical system.

The optical pickup 10 constructed as described above
In the optical system for one CD, the first laser diode LD
The first laser beam L1 from No. 1 passes through the grating G, is partially reflected by the first beam splitter BS1, passes or reflects through the dichroic beam splitter DBS, the collimator C, and the mirror M, and returns to the CD.
The light is condensed on the optical disk D by the objective lens OL1 via the aperture limiting aperture R.

The reflected light from the optical disk D passes through the first multi-lens ML1 via the objective lens OL, the aperture limiting aperture R for CD, the mirror M, the collimator C, the dichroic beam splitter DBS and the first beam splitter BS1. Is incident on the first photodiode PD1, and the change in the reflected light causes the CD
The information recorded on the data recording surface is read.

In the DVD optical system of the optical pickup 101, the second laser diode L
The second laser light L2 from D2 is partially reflected by the second beam splitter BS2, passes or reflects through the dichroic beam splitter DBS, the collimator C, and the mirror M, respectively, and passes through the aperture limiting aperture R for CD. The light is focused on the optical disk D by the lens OL1.

The reflected light from the optical disk D passes through the second multi-lens ML2 via the objective lens OL, the aperture limiting aperture R for CD, the mirror M, the collimator C, the dichroic beam splitter DBS and the second beam splitter BS2. Is incident on the second photodiode PD2, and the change in the reflected light causes the DV of the optical disk D to change.
The information recorded on the recording surface for D is read.

According to the optical pickup 101, FIG.
Similarly to the optical pickup 100 shown in FIG. 4, a laser diode for a CD and a laser diode for a DVD are mounted, and a CD and a DVD are provided by having respective optical systems.
It is possible to play.

[0022]

The present inventor can construct an optical disk system having a different wavelength, such as a CD or a DVD, with respect to such a conventional optical pickup. We have already proposed an optical device capable of realization and cost reduction and an optical disk device using the same.

FIGS. 16 to 19 show an example thereof. According to the compatible optical pickup 1a shown in FIG.
Laser diode LD1 for CD (oscillation wavelength 780n
m) and a laser diode LD2 for DVD (oscillation wavelength 6
50 nm).

The optical pickup 1a has an optical system individually (ie, discretely) or on a common substrate (ie, monolithically), and is formed adjacent to each other and in parallel, for example, at 780 nm. 780, a laser diode LD having a first laser diode LD1 for emitting laser light of a wavelength in the band and a second laser diode LD2 for emitting laser light of a wavelength in the 650 nm band.
A grating G, a beam splitter BS, a collimator C, a mirror M, an aperture limiting aperture R for CD, an objective lens OL, a multi-lens ML, and a photodiode P for the nm band and transparent to the 650 nm band.
D are respectively provided at predetermined positions. In the photodiode PD, a first photodiode that receives light in the 780 nm band and a second photodiode that receives light in the 650 nm band are formed adjacent to and parallel to each other.

In the optical pickup 1a, the first laser light L1 from the first laser diode LD1 passes through the grating G, is partially reflected by the beam splitter BS, and has an aperture limiting aperture for the collimator C, mirror M, and CD. R passes through (reflects) with the objective lens O
L converges on the optical disc D.

The reflected light from the optical disk D passes through the multi-lens ML via the objective lens OL, the CD aperture limiting aperture R, the mirror M, the collimator C, and the beam splitter BS, and passes through the photodiode PD (first photodiode). ), And this change in reflected light causes C
The information recorded on the recording surface of the optical disc D, such as D, is read.

Then, in the optical pickup 1a, the second laser light L2 from the second laser diode LD2 is also
The light is condensed on the optical disk D by following the same path as described above, and the reflected light is incident on the photodiode PD (second photodiode). Due to the change in the reflected light, the light is reflected on the recording surface of the optical disk D such as a DVD. Reading of the recorded information is performed.

According to this optical pickup 1a, a laser diode for CD and a laser diode for DVD are mounted, and the reflected light is coupled to the photodiode for CD and the photodiode for DVD by a common optical system.
It enables playback of CDs and DVDs.

FIG. 17 is a perspective view of a main part of the laser diode LD. For example, a semiconductor block 13 in which a PIN diode 12 as a photodetection element for monitoring is formed on a protrusion 21 a provided on a disc-shaped base 21.
Is fixed, and the first laser diode 14 (L
D1) and the second laser diode 15 (LD2). Further, a terminal 22 is provided through the base 1 and is connected to the first and second laser diodes 14, 15 or the PIN diode 12 by a lead 23 to supply power for driving each diode. Is done.

FIG. 18A is a plan view of a main part of the laser diode taken from a direction perpendicular to the laser beam emission direction. FIG. 18B is a plan view of the laser diode taken from the laser beam emission direction. FIG. A first laser diode 14 (LD1) and a second laser diode 15 (LD2) are discretely disposed above a semiconductor block 13 on which a PIN diode 12 is formed. These laser diodes may be monolithically arranged as described later, as shown in FIG.

Here, the PIN diode 12 has, for example, two divided regions, and the first and second laser diodes 14, 15 or each of LD1, LD2 are emitted toward the rear (rear) side. Sensing the laser light,
The intensity is measured and the first and second laser diodes 14, 15 or LD are controlled so that the intensity of the laser light is constant.
1. APC (Automatic Po
wer Control) control.
The PIN diode 12 may be one without being divided (can be used by switching).

The laser beam emitting portion E1 of the first laser diode 14 and the laser beam emitting portion E of the second laser diode 15
The interval d of 2 is set, for example, in a range of about 200 μm or less (eg, about 100 μm). Each laser beam emitting part E
For example, laser beams L1 and L2 having a wavelength of 780 nm and 650 nm, respectively, are emitted from E1 and E2 in the same direction (parallel).

FIG. 19A is a plan view of a main part of the photodiode PD. For example, a first photodiode 16 for receiving light in the 780 nm band and a second photodiode 18 for receiving light in the 650 nm band are formed adjacent to and parallel to each other.

Here, the first photodiode 16 is divided into six parts (a1, b1, c1, d1, e1,.
f1). The laser light in the 780 nm band emitted from the first laser diode 14 is split into three laser lights by the grating G, passes through the optical system, and is reflected as light reflected from an optical disk D such as a CD in FIG. As shown in (a), the first photodiode 1
The light is incident on the light spot 6 as three spots (S1a, S1b, S1c).

The second photodiode 18 has a configuration divided into four parts (a2, b2, c2, d2) as shown in the drawing. The laser light in the 650 nm band emitted from the second laser diode 15 passes through the above optical system and
As reflected light from an optical disk D such as VD, FIG.
As shown in (a), the light is incident on the second photodiode 18 as one spot S2.

First and second photodiodes 16 and 18
, That is, the distance d between the center line of the first photodiode 16 and the center line of the second photodiode 18, for example.
Is, for example, in the range of about 200 μm or less (for example, 100 μm).
m). Here, for example, the first
The distance between the laser light emitting portion E1 of the laser diode 14 and the laser light emitting portion E2 of the second laser diode 15 is set to be substantially equal.

As described above, by setting the distance between the laser light emitting portions of the first and second laser diodes and the distance between the first and second photodiodes, the first laser can be used by using a common optical member. It is possible to irradiate the light emitted from the diode and the second laser diode to an optical disc such as a CD or DVD, and to make the reflected light from the optical disc enter the first photodiode and the second photodiode, respectively.

In the photodiode PD (the first photodiode 16 and the second photodiode 18), the spot S1 of the incident laser beam as described above.
a, S1b, S1c, the spot diameter of S2, a change in position, and the like can be detected.

As an optical pickup of an optical disk device,
From the signal obtained by the photodiode PD,
The tracking error signal, the focus error signal, and the information signal recorded on the optical disk are read. Extraction of these signals is performed as follows.

That is, in the first photodiode 16, the signal a 1 obtained at the central spot S 1 a incident on the six divided first photodiode 16,
Using b1, c1 and d1, the following equation (1) gives C
An information signal RF1 recorded on an optical disk such as D can be obtained. RF1 = a1 + b1 + c1 + d1 (1)

The signals a1, b1, c1 and d
1, the focus error signal FE1 can be obtained by the following equation (2). FE1 = (a1 + c1)-(b1 + d1) (2)

Using the signals e1 and f1 obtained at the spots S1b and S1c on both sides incident on the first photodiode 16 divided into six, a tracking error signal TE1 is obtained by the following equation (3). be able to. TE1 = e1-f1 (3)

On the other hand, in the second photodiode 18, the signals a2 and b obtained at the central spot S2 incident on the quadrant divided second photodiode 18 are obtained.
2, c2, and d2, and DV
An information signal RF2 recorded on an optical disk such as D can be obtained. RF2 = a2 + b2 + c2 + d2 (4)

The signals a2, b2, c2 and d
2, a focus error signal FE2 can be obtained by the following equation (5). FE2 = (a2 + c2)-(b2 + d2) (5)

The signals a2, b2, c2 and d
19, the tracking error signal TE2 can be obtained by the DPD (Differential Phase Detection) method as shown in FIG. 19B. For example, signals a2 and b2 and signals c2 and d
After comparing the two phases, the adder AD performs an addition operation to obtain a tracking error signal TE2. According to the DPD method, stable tracking without offset in one spot can be performed.

In the optical disk reproducing / recording apparatus using this laser coupler, as described above, the focus error signal due to the vertical swing of the optical disk such as CD or DVD is detected, and the focusing is performed according to the obtained focus error signal. Apply servo. Further, a tracking error signal is detected, and a tracking servo is applied according to the obtained tracking error signal.

This laser coupler is equipped with a laser diode LD1 for CD (oscillation wavelength 780 nm) and a laser diode LD2 for DVD (oscillation wavelength 650 nm).
A compatible optical pickup capable of reproducing CDs and DVDs can be configured.

This laser coupler comprises a first laser diode LD1 and a second laser diode LD2 which are arranged adjacently and in parallel, and a first photodiode 16 and a second photodiode 18 which are arranged adjacently and in parallel. There is no need to align optical axes from laser diodes having different oscillation wavelengths, and the light emitted from the first laser diode LD1 and the second laser diode LD2 can be converted to a CD or DVD using a common optical member. And the reflected light from the optical disk is incident on the first photodiode and the second photodiode, respectively. Therefore, the number of parts is smaller than that shown in FIGS. 14 and 15, and it is easy to assemble, and it is possible to reduce the size and cost.

[0049]

FIG. 20 shows a known laser coupler in which a laser diode LD as a light emitting element and photodetectors PD1 and PD2 as light receiving elements for detecting RF signals and the like are provided on a common substrate 11. And an optical pickup is configured using the same. This laser coupler is housed in a package having a cover glass 3 and a λ / 4 (or λ / 2 plate) 50 at the emission position on the optical disk (not shown) side. Laser diode LD
The laser light L emitted from the emission surface is reflected and partially transmitted by the inclined surface (spectral surface) 20 a of the prism 20.

In this case, the current I of the laser diode LD
And the light output L _out have a relationship as shown in FIG. This light output is monitored by, for example, making the rear-side emission laser light L ′ incident on a photodetector (PIN-PD) including a PIN diode provided behind the rear end face 51 of the laser element LD as shown in FIG. And
This is used as a monitor of the light output of the laser light L emitted from the front surface 52.

However, in general, the wavelength of the light emitted from the laser element has a temperature dependence, and if the PIN-PD is arranged in an inclined state with respect to the emission direction of the laser light, the surface protective film is not provided. Also has a temperature dependence and varies depending on the wavelength of incident light.

This will be described in detail. First, when the system temperature rises, the PIN-PD detection output (Imo
In the case where the temperature change of n) shows a positive characteristic, FIG.
As described above, the optical output of the PIN-PD increases. At this time,
The wavelength of the laser light L (L ') becomes longer due to the temperature rise of the laser LD, and generally has a temperature dependence of about 0.25 nm / ° C.

At this time, the wavelength of the emitted light of the laser is λ ₁ →
When the wavelength is increased to λ ₁ ′, the end face protective film 53 of, for example, alumina or the like is set so that the reflectance R at the laser end face increases (the transmission component decreases) as shown in FIG. For example, since the PIN-PD has a positive temperature characteristic and the emission intensity from the end face decreases due to an increase in the laser wavelength, these are offset as a whole, and the emission is always constant with respect to a temperature change. APC for strength
Functions, and a constant PIN-PD light output is always obtained with respect to a temperature change, and this need only be monitored (see Japanese Patent No. 2663437).

However, when such a technique is applied to a two-wavelength laser as shown in FIGS. 16 to 19 (ie, a light source provided with laser diodes LD1 and LD2 having different wavelengths), the following problem occurs. .

For example, even with a two-wavelength laser, it is not common to operate two different lasers at the same time, so that even one PIN-PD for monitoring is often shared. However, since the wavelengths of the laser elements are different from each other, generally, for different wavelengths, the temperature characteristics of the two lasers are similarly reversed (a decrease in emission intensity which offsets the temperature characteristics of the PIN-PD). It is not easy to do.

That is, since the reflection film (the above-described protective film 53) on the laser end face can be formed only with one kind of film thickness because the laser is small, wavelengths different from each other (for example, λ
_{1 (} = 780 nm, λ ₂ = 650 nm), the reflectivity differs as shown in FIG. 22 (d is the thickness of the protective film in the figure), and the wavelength of the emitted light due to the temperature change of the laser. This is because the direction of change of the reflectance at the end face is not always constant with respect to the change (rather, it is usually not constant).

The present invention has been made in view of the above-described problems. Particularly, even when a plurality of laser elements are monitored by PDs having the same characteristics, the temperature characteristics are always offset by light of an arbitrary wavelength. It is an object of the present invention to provide an optical device such as a laser coupler capable of obtaining a stable output by using the same, and an optical disk device using the same.

[0058]

That is, according to the present invention, a plurality of light emitting elements respectively emitting a plurality of light beams different from each other are juxtaposed in a direction intersecting the light emitting direction, and the plurality of light beams are disc-shaped or the like. In an optical device provided with a plurality of light receiving elements for irradiating a recording medium and receiving reflected light thereof, and an optical disc device using the same, at least one of the emitted lights of the plurality of light emitting elements An optical device and an optical disk device, characterized in that an optical means whose reflectance or transmittance to light varies with temperature is provided in an optical path between the plurality of light emitting elements and the plurality of light receiving elements. It is.

According to the optical device and the optical disk device, the reflectance or the transmittance of at least one outgoing light of each of the plurality of light emitting elements changes depending on the temperature (for example, the reflectivity increases when the temperature rises). Since the optical means such as a reflective film is provided in the optical path between the plurality of light-emitting elements and the plurality of light-receiving elements, even if a plurality of light-emitting elements different from each other are used, the other of the emitted light As described above, the end face of the light emitting element that emits the emitted light is designed so that the change in the physical properties of the emitted light (for example, the wavelength increases when the temperature rises) cancels out the temperature characteristics of the monitoring element such as the PIN-PD. When a protective film is set,
With respect to the light emitting element that cannot be canceled out even by this, the temperature characteristics can be offset as a whole by the optical means such as the optical film provided on the end face of the prism having the physical properties such as increasing the reflectance when the temperature rises. . Therefore, even when a plurality of light emitting elements are used, the degree of freedom in adjusting physical properties such as arbitrary wavelengths is increased, and stable output characteristics can always be obtained.

Further, the present invention provides an optical device provided with a light emitting element for emitting predetermined light and a light receiving element for irradiating the light emission to an information recording medium such as a disk and receiving the reflected light. And an optical disc device using the same, wherein an optical unit whose reflectance or transmittance for the emitted light changes with temperature is provided in an optical path between the light emitting element and the light receiving element. An optical device and an optical disk device are also provided.

According to the optical device and the optical disk device, the optical means such as the reflection film whose reflectance or transmittance for the emitted light changes with temperature (for example, the reflectance decreases when the temperature rises) is composed of the light emitting element and the light receiving element. As described above, the temperature characteristic of the monitoring element such as the PIN-PD is changed with respect to a change in the physical properties of the emitted light (for example, an increase in the wavelength when the temperature rises). If the end face protection film is set to cancel, RF
The temperature characteristics of the light receiving element such as a signal (the output increases when the temperature rises) can be offset by the decrease in the amount of incident light received due to the decrease in the reflectivity, and even a single light emitting element as a whole Temperature characteristics can be offset, and stable output characteristics can always be obtained.

[0062]

BEST MODE FOR CARRYING OUT THE INVENTION In the optical device and the optical disk device of the present invention, of the light emitted from the plurality of light emitting elements,
It is desirable that an optical film in which the reflectance or transmittance for one emitted light and the reflectance or transmittance for another emitted light change in opposite directions depending on temperature is provided in the optical path as the optical means. .

In this case, the plurality of light-emitting elements (or the predetermined light-emitting elements) and their respective emitted lights are guided to an object to be illuminated such as the disk-shaped information recording medium via a spectral surface, and the reflected lights are guided. An optical member for guiding the plurality of light receiving elements (or the light receiving elements) from the light-splitting surface and the light-receiving element are configured as an optical coupler provided on a common base, and the optical film is formed on the light-splitting surface. It is good to be provided. This optical coupler is preferably included in an optical pickup of an optical disk device.

Further, the plurality of light beams are emitted as output light from the first end faces of the plurality of light emitting elements, and the plurality of monitor lights are respectively emitted from the second end faces to control the intensity of the output light. A monitor light-receiving element for detecting the monitor light, and among the plurality of monitor lights,
A protective film is formed on the second end face so as to exhibit a reflectance or a transmittance such that the temperature-dependent characteristic of the intensity of one monitor light and the temperature-dependent characteristic of the detection output of the monitor light receiving element are opposite to each other. The one monitor light corresponds to the one outgoing light, and the reflectance or transmittance of the optical film with respect to the other outgoing light corresponding to the other monitor light changes according to the temperature, and the other outgoing light changes. The temperature-dependent properties of the emitted light should be canceled.

The plurality of light emitting elements are preferably configured as, for example, a two-wavelength laser that emits laser beams having different wavelengths.

Further, the predetermined light is emitted as output light from the first end face of the light emitting element, and monitor light is emitted from the second end face. The monitor light is emitted to control the intensity of the output light. A protective film having a monitoring light receiving element for sensing, and exhibiting a reflectance or a transmittance such that the temperature dependency of the intensity of the monitor light and the temperature dependency of the detection output of the monitoring light receiving element are opposite to each other. Is preferably formed on the second end surface.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 4A is an explanatory diagram showing a schematic configuration of the laser coupler 1a according to the present embodiment. The laser coupler 1a is loaded in a concave portion of the first package member 2,
It is sealed by a transparent second package member 3 such as glass.

FIG. 4B is a perspective view of a main part of the laser coupler 1a. For example, a semiconductor block 13 on which a PIN diode 12 as a photodetection element for monitoring is formed is disposed on an integrated circuit substrate 11 which is a substrate obtained by cutting out a single crystal of silicon. First laser diode LD as light emitting element
A monolithic laser diode 14a in which the first and second laser diodes LD2 are mounted on one chip is arranged.

In this embodiment, for example, λ ₁ = 780
a first front photodiode 16 and a rear first photodiode 17 for receiving light in the nm band, λ ₂ = 650 nm
A front second photodiode 18 and a rear second photodiode 19 that receive light in a band are formed below a prism 20 fixed on the substrate 11.

Here, as shown in FIG. 5, the front first photodiode 16 is divided into four parts (a1, b1, c1, d1).
Then, the rear first photodiode 17 is also divided into four parts (i1,
j1, k1, and l1).

A first laser diode LD1 is mounted on a block 13 fixed on a substrate 11, and a 780 nm band laser beam L emitted from this laser diode is emitted.
1 is reflected by the spectral surface 20a of the prism 20 and further passes through the optical system as reflected light from an optical disk (CD), through the prism 20, and spots on the front and rear first photodiodes 16 and 17 one by one. S1a, S1
incident as b.

Also, the front second photodiode 18
Division (a2, b2, c2, d2, e2, f2, g2, h
2), and the rear second photodiode 19 is divided into four parts (i
2, j2, k2, l2).

The laser light L2 in the 650 nm band emitted from the second laser diode LD2 also passes through the above optical system,
The reflected light from the optical disk (DVD) is incident on the front and rear second photodiodes 18 and 19 as spots S2a and S2b, respectively.

The distance between the front first photodiode 16 and the front second photodiode 18 and the rear first photodiode
Photodiode 17 and rear second photodiode 1
The interval 9 is set, for example, in a range of about 200 μm or less (eg, about 100 μm). Here, for example, the laser beam emitting unit E1 of the first laser diode LD1 is used.
Is set so as to be substantially equal to the distance between the laser beam emitting portion E2 of the second laser diode LD2.

As described above, the distance between the laser light emitting portions of the first and second laser diodes, and the first and second laser diodes
By setting the distance between the photodiodes, the light emitted from the first laser diode and the second laser diode is irradiated on an optical disc such as a CD or DVD using a common optical member, and the reflected light from the optical disc is reflected on the first photodiode. The light can be incident on the diode and the second photodiode, respectively.

In the above-mentioned photodiodes (front and rear first photodiodes 16 and 17 and front and rear second photodiodes 18 and 19), the spots S1a, S1b, S2a and S2b of the incident laser beam as described above. A diameter, a position change, and the like can be detected.

When an optical pickup of an optical disk device is constituted by using this laser coupler, a tracking error signal, a focus error signal, and an information signal recorded on an optical disk are read from the signal obtained by the photodiode PD. Is performed. Extraction of these signals is performed as follows.

That is, the front and rear first photodiodes 16,
17, spots S1a incident on the front and rear first photodiodes 16 and 17 divided into four parts, respectively.
The signals a1, b1, c1, d1, and
Using i1, j1, k1 and l1, the information signal RF1 recorded on an optical disc such as a CD is expressed by the following equation (6).
Can be requested. RF1 = a1 + b1 + c1 + d1 + i1 + j1 + k1 + 11 (6)

The signals a1, b1, c1, d
The focus error signal FE1 can be obtained from the following equation (7) using 1, i1, j1, k1, and l1. FE1 [(a1 + d1)-(b1 + c1)]-[(i1 + 11)-(j1 + k1)] (7)

The signals a1, b1, c1, d
Using 1, i1, j1, k1, and l1, the tracking error signal TE1 can be obtained by the following equation (8). TE1 = [(a1 + b1)-(c1 + d1)] + [(i1 + j1)-(k1 + 11)] (8)

On the other hand, the front and rear second photodiodes 18,
In 19, the signals a2, b2, obtained at the spots S2a, S2b incident on the front and rear second photodiodes 18, 19 divided into eight and four, respectively.
c2, d2, e2, f2, g2, h2, i2, j2, k
The information signal RF2 recorded on an optical disk such as a DVD can be obtained by the following equation (9) using 2 and l2. RF2 = a2 + b2 + c2 + d2 + e2 + f2 + g2 + h2 + i2 + j2 + k2 + l2 (9)

The signals a2, b2, c2, d
2, e2, f2, g2, h2, i2, j2, k2 and l
2, a focus error signal FE2 can be obtained by the following equation (10). FE2 = [(a2 + d2 + e2 + h2)-(b2 + c2 + f2 + g2)]-[(i2 + 12)-(j2 + k2)] (10)

The signals a2, b2, c2, d2, e2, f2, and
Using g2 and h2, as shown in FIG. 10B described later, DPD (Differential Phase Detecti
The tracking error signal TE2 can be obtained by the on) method. For example, in a first adder (wideband) AD1, signals a2 and b2, signals c2 and d2, and signals e2 and f
2. The addition operation of the signals g2 and h2 is performed, and the phase comparator PC sums the signals a2 and b2, the signals c2 and d2, the signals g2 and h2, and the signals e2 and f2.
After the phase of the sum signal is compared with the sum, a second adder AD2 performs an addition operation to obtain a tracking error signal TE2. According to the DPD method, stable tracking without offset in one spot can be performed.

In the optical disk reproducing / recording apparatus using this laser coupler, as described above, the focus error signal due to the vertical shake of the optical disk such as a CD or DVD is detected, and the focusing is performed according to the obtained focus error signal. Apply servo. Also,
A tracking error signal is detected, and a tracking servo is applied according to the obtained tracking error signal.

This laser coupler is equipped with a laser diode LD1 for CD (oscillation wavelength 780 nm) and a laser diode LD2 for DVD (oscillation wavelength 650 nm).
It is possible to configure a compatible optical pickup that enables reproduction of CD and DVD.

The laser coupler comprises a first laser diode LD1 and a second laser diode LD2 arranged adjacently and in parallel with each other, and front and rear first photodiodes 16 and 17 arranged adjacently and in parallel with each other. And the front and rear second photodiodes 18 and 19, there is no need to align optical axes from laser diodes having different oscillation wavelengths, and the first laser diode LD1 and the second laser The light emitted from the diode LD2 is applied to an optical disc such as a CD or DVD, and the reflected light from the optical disc is transmitted to the front and rear first photodiodes 1.
6, 17 and the front and rear second photodiodes 18 and 19, respectively. Therefore, the number of parts is smaller than that shown in FIGS.
Miniaturization and cost reduction are possible.

FIG. 1 is an enlarged sectional view of the laser coupler according to the present embodiment. That is, a plurality (here, two)
Photodetectors 16 and 17, 1 as laser light receiving elements for detecting laser diodes LD1, LD2 and RF signals, etc.
8 and 19 show a laser coupler provided on a common substrate 11, and an optical pickup is configured using the laser coupler.
This laser coupler is provided with a cover glass 3 and a λ / 4 (or λ / 2 plate) 50 at the emission position on the optical disk (not shown) side.
Are housed in a package having Laser light L emitted from the emission surfaces of laser diodes LD1 and LD2
1, L2 is reflected and partially transmitted on the inclined surface (spectral surface 20a) of the prism 20.

A beam splitter (PBS) film is actually formed on the spectral surface 20a of the prism 20, as shown in FIG. 2, and reflects the emitted laser light, which goes to and returns from the optical disk and has a polarization direction of about Rotate 90 degrees (s-polarized light →
(p-polarized light), the same detection as before the addition of the wave plate 50 becomes possible by setting the characteristics of the polarizing PBS film to ps reverse.

The configuration of the above laser coupler is the same as that shown in FIG. 20, but what should be noted here is that a specific reflection film (for example, Si) is formed on the spectral surface 20a of the prism 20.
O-based or TiO-based) 54 is provided, and when the temperature rises, one of the laser beams L1 (λ ₁ = λ _{1) of the} laser beams L1 and L2 emitted from the two-wavelength lasers LD1 and LD2 described above.
780 nm), and at the same time, the reflectivity of the other laser beam L2 (λ ₂ = 650 nm) increases. At the same time, a protective film 53 made of alumina or the like is provided on the monitor-side end faces of the laser diodes LD1 and LD2 to offset the temperature characteristics of the laser light L1 with respect to the PIN-PD. .

As described above, the laser diode LD
1. The optical output of the LD 2 is applied to the photodetector 12 (PIN-PD), which is a PIN diode provided behind the rear end face 51 of the laser element, and outputs the laser light L on the rear side.
The laser beams L1 and L2 emitted from the front surface 52 are monitored by inputting 1 'and L2'.
Used as a monitor of the optical output of

However, in general, the wavelength of the light emitted from the laser element has a temperature dependency, and if the PIN-PD is arranged in an inclined state with respect to the emission direction of the laser light, the surface protection of the PIN-PD is prevented. As described above, the reflectivity of the film also has a temperature dependence and varies depending on the wavelength of the incident light.

Here, consider the case where the temperature rises. As the temperature increases, the optical output of the PIN-PD 12 increases (see FIG. 21B), and the oscillation wavelength of the laser increases. Therefore, in the vicinity of the reflection film 53 of the laser facet 51 laser wavelengths (lambda _1, for example 780 nm), wavelength lambda ₁ →
The longer the wavelength λ ₁ ′, the higher the reflectance. At this time, the transmitted laser light L
As for the intensity of 1 ′, the transmission ratio decreases due to the longer oscillation wavelength, while the optical output of the PIN-PD 12 increases (sensitivity increases). The light output of the PD 12 is constant.

In this way, if the optical output of the PIN-PD is controlled to be constant, the APC can be controlled so that the output of the laser becomes constant regardless of the temperature characteristics of the laser (this detailed description will be given later). Is a patent no.
No. 437).

However, as described above, in the two-wavelength laser as in this embodiment, the reflection film 53 on the laser end face is used.
Can be formed with only one kind of film thickness due to the small size of the laser. Therefore, the reflectivity differs for laser beams having mutually different wavelengths (for example, λ ₁ , for example, 780 nm, λ ₂ , for example, 650 nm), and The direction of change in reflectivity at the end face is not always constant with respect to a change in the wavelength of the emitted light due to a change in the temperature of the laser.

This problem has been solved in the present embodiment as follows. For laser beams having different wavelengths (λ ₁ , for example, 780 nm, λ ₂ , for example, 650 nm), the temperature characteristics of the optical output of the PIN-PD when the temperature rises have the same relationship. Since the wavelength is different between λ ₁ and λ ₂ , the change in reflectivity of the laser end face with respect to the change in wavelength should generally be different (see FIG. 22). Therefore, 78
Even if the temperature characteristics can be offset with respect to the laser light in the 0 nm band, the temperature characteristics cannot be offset with respect to the laser light in the 650 nm band which is a different wavelength. For example, it is assumed that the reflectance R of the reflection film 53 on the laser end face with respect to the laser light in the 650 nm band changes less with an increase in wavelength.

At this time, it is necessary to cancel the temperature characteristics for the laser beams having different wavelengths. Therefore, for example, by adjusting the thickness of the reflection film 54 on the end face of the prism shown in FIG. 1, the temperature characteristics can be offset as a whole at different wavelengths.

That is, when the film thickness of the reflection film 54 on the prism end face becomes large in the 650 nm band, the reflectance becomes 780 n
By setting the reflectivity to be small in the m-band (FIG. 3B), the laser light in the 650 nm band (λ ₂ ) has a small reflectivity at the laser end face (FIG. 22).
Even if the optical output of N-PD 12 is controlled to increase and the laser output is reduced by APC (PIN-P
Even if the temperature characteristic of D cannot be offset), the amount of reflection of the laser beam L2 by the reflection film 54 on the end face of the prism increases, and this increase offsets the decrease in laser output.

As a result, the temperature characteristics of the laser beam L2 at the time of temperature rise can be offset, and the laser output can be stabilized. For this reason, even if the protective film 53 on the laser end face has wavelength dependence, the reflection film 54 on the prism end face functions so that this does not affect the laser output of other wavelengths. The temperature characteristics of the laser beam L2 as well as the laser beam L2 can be offset, and the degree of freedom in design for an arbitrary wavelength increases.

The photodiode 16 for signal detection
, 17, 18 and 19 also tend to increase in output when the temperature rises, but this increase in output can be offset by the decrease in the reflectivity of the reflection film 54 on the prism end face, and the increase in the output of the laser light L2. With respect to the above, these can be offset by setting the decrease in the laser output by the APC to be equal to the increase in the reflectance of the reflection film 54 on the prism end face and the increase in the photodiode output.

The wavelength dependence of the reflectance of the reflection film 54 on the prism end face depends on the film thickness, material, etc., as shown in FIGS. 3 (a), 3 (b), 3 (c), 3 (d), and 3 (e). There are various types, and an appropriate one may be selected from these. For example, the thickness and material (SiO-based, T
The wavelength dependency of the reflectance can be controlled by various designs, such as a stacked film structure of iO-based or SiO-based / TiO-based or a film thickness ratio thereof. In this case, P
A laser beam (for example, such as the above-described laser beam L1) to be used for canceling the temperature characteristics of the IN-PD is selected.

Next, the laser coupler according to the present embodiment,
The configurations of the optical pickup and the optical disk device will be described in more detail.

FIG. 6 shows first laser diodes LD1 and 650n that emit laser light having a wavelength in the 780 nm band, for example.
FIG. 14 shows a monolithic laser diode 14a in which a second laser diode LD2 that emits laser light having a wavelength in the m band is mounted on one chip.

For example, a PI as a photodetector for monitoring is provided on a projection 21a provided on a disc-shaped base 21.
A semiconductor block 13 on which an N diode 12 is formed is fixed, and first and second laser diodes L
A monolithic laser diode 14a having D1 and LD2 on one chip is arranged. Further, a terminal 22 is provided through the base 21, and the first and second laser diodes LD 1, LD 2,
Alternatively, it is connected to the PIN diode 12 and the driving power of each diode is supplied.

FIG. 7A is a plan view of a main part of the laser diode from the direction perpendicular to the laser light emission direction, and FIG. 7B is a plan view of the laser diode perpendicular to the laser light emission direction. FIG. PIN diode 1
A monolithic laser diode 14a having a first laser diode LD1 and a second laser diode LD2 on a single chip is disposed above a semiconductor block 13 in which the semiconductor laser 2 is formed.

The PIN diode 12 senses the laser light emitted to the rear side of the first and second laser diodes LD1 and LD2, measures the intensity thereof, and measures the intensity of the laser light so that the intensity of the laser light becomes constant. APC control for controlling the drive current of the first and second laser diodes LD1 and LD2 is performed.

The above monolithic laser diode 14
a will be described. As the first laser diode LD1, an n-type GaAs buffer layer 31, an n-type AlGaAs cladding layer 32, and an active layer 3 are formed on an n-type GaAs substrate 30.
3. A p-type AlGaAs cladding layer 34 and a p-type GaAs cap layer 35 are laminated. The region 41 is insulated from the surface of the p-type GaAs cap layer 35 to a depth in the middle of the p-type AlGaAs cladding layer 34 to form a stripe having a current confinement structure.

On the other hand, as the second laser diode LD2, an n-type GaAs buffer layer 31, an n-type InGaP buffer layer 36, an n-type AlGa
InP clad layer 37, active layer 38, p-type AlGaIn
A P cladding layer 39 and a p-type GaAs cap layer 40 are laminated. From the surface of the p-type GaAs cap layer 40 to the p-type A
The region 41 is insulated to a certain depth in the 1GaInP cladding layer 39 to form a stripe having a current confinement structure.

In the first laser diode LD1 and the second laser diode LD2, the p-type GaAs cap layers 35 and 40 are connected to the p-electrode 42, and the n-type GaAs substrate 30 is connected to the n-electrode 43. ing. The monolithic laser diode 14a is connected and fixed to the electrode 13a formed on the semiconductor block 13 from the p-electrode 42 side by soldering or the like.

The distance d between the laser beam emitting portion of the first laser diode LD1 and the laser beam emitting portion of the second laser diode LD2 is set to a range of, for example, about 200 μm or less (eg, about 100 μm). For example, laser beams L1 and L6 having a wavelength of 780 nm
Laser light L2 having a wavelength in the 50 nm band is emitted in substantially the same direction (substantially parallel).

On the other hand, the distance between the first and second photodiodes 16-17 and 18-19 is also 2 in the same manner as described above.
The light emitted from the first laser diode and the second laser diode is applied to an optical disc such as a CD or DVD using a common optical member, and the reflected light from the optical disc is set to a range of about 00 μm or less (for example, about 100 μm). Can be coupled to the first photodiode and the second photodiode, respectively.

Next, the first laser diode LD1
And a method of forming a monolithic laser diode 14a in which the second laser diode LD2 is mounted on a chip.

First, as shown in FIG. 8 (a), an n-type GaAs buffer layer 31, an n-type AlGaAs cladding, Layer 32, an active layer (a multiple quantum well structure having an oscillation wavelength of 780 nm) 33, a p-type AlGaAs cladding layer 34,
Type GaAs cap layers 35 are sequentially stacked.

Next, as shown in FIG. 8B, a region left as the first laser diode LD1 is protected by a resist film (not shown), and sulfuric acid-based non-selective etching is performed.
The first laser diode L is formed by wet etching (EC1) such as hydrofluoric acid-based AlGaAs selective etching.
The n-type AlGaAs cladding layer 32 is formed in a region other than the D1 region.
The above laminate up to is removed.

Next, as shown in FIG. 9C, an n-type InGaP buffer layer 36 and an n-type InGaP buffer layer 36 are AlG
aInP cladding layer 37, active layer (oscillation wavelength 650 nm)
), A p-type AlGaInP cladding layer 39, and a p-type GaAs cap layer 40.

Next, as shown in FIG. 9D, a region left as the second laser diode LD2 is protected by a resist film (not shown), and sulfuric acid-based cap etching and phosphoric acid-hydrochloric acid-based Wet etching (EC2) such as original selective etching and hydrochloric acid-based separation etching
N-type InGa in a region other than the laser diode LD2 region
The stacked body up to the P buffer layer 36 is removed, and the first laser diode LD1 and the second laser diode LD2 are separated.

Next, as shown in FIG. 10E, a portion serving as a current injection region is protected by a resist film (not shown), an impurity D is introduced by ion implantation or the like, and p-type Ga is removed.
From the surface of the As cap layers 35 and 40, p-type AlGaAs
A region 41 insulated to a certain depth in the cladding layers 34 and 39 is formed to form a stripe having a current confinement structure.

Next, as shown in FIG.
Ti / Ti is connected so as to connect to the aAs cap layers 35 and 40.
A p-type electrode 42 such as Pt / Au is formed.
AuGe / Ni / A to connect to the aAs substrate 30
An n-type electrode 43 such as u is formed, and a monolithic laser diode 14a in which a desired first laser diode LD1 and a desired second laser diode LD2 are mounted on one chip through a pelletizing process.

FIG. 11 shows the configuration of an optical pickup using the laser coupler according to the present embodiment. The laser beams L1 and L2 emitted from the first and second laser diodes incorporated in the laser coupler 1a are collimated by a collimator C, a mirror M, a CD aperture limiting aperture R and an objective lens O.
The light is incident on an optical disk D such as a CD or DVD via L. The reflected light from the optical disc D follows the same path as the incident light, returns to the laser coupler, and is received by the first and second photodiodes built in the laser coupler.

In this laser coupler, the first and second photodiodes can be divided as shown in FIG. In this case, the front first photodiode 1
The region d1 of No. 6 and the regions a2 and e2 of the front second photodiode 18 are shared, and the signal d1 is obtained by adding the signals a2 and e2. Further, the region 11 of the rear first photodiode 17 and the region i2 of the rear second photodiode 19 are shared.

The above-mentioned laser coupler 1a has two wavelength lasers LD1 and LD2 mounted thereon.
The same effect as described above can be obtained for a laser coupler, an optical pickup, and an optical disk device equipped with a wavelength laser.

For example, as described above for the laser beam L1, the reflection film 53 on the laser end face 51 is set near the laser wavelength so that as the wavelength becomes longer, the reflectivity increases so as to increase the whole. The light output of the PIN-PD 12 becomes constant with respect to changes in temperature.

Thus, by controlling the optical output of the PIN-PD to be constant, it is possible to control the APC so that the output of the laser is constant irrespective of the temperature characteristics of the laser. Is a patent no.
No. 437).

At the same time, the output of the photodiodes 16 and 17, 18 and 19 for signal detection also tends to increase when the temperature rises. This increase in output is reflected by the reflection film 54 on the prism end face with respect to the laser light. By setting the rate to decrease (the amount of light incident on the photodiode decreases and the output decreases), the offset can be offset.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to these embodiments.

For example, the light emitting element used in the present invention is not limited to a laser diode, and a light emitting diode (LED) can be used.

The emission wavelengths of the first and second laser diodes are not limited to the 780 nm band and the 650 nm band, but may be wavelengths employed in other optical disk systems. That is, an optical disk system of a combination other than a CD and a DVD using a combination of various wavelengths can be adopted.

[0128] Even if the wavelength is the same, light having different power or light having different polarization direction may be used. Light having different physical properties such as wavelength is not limited to two types, and may be more than two types. When there are three or more types of light, for example, an optical film whose reflectance for the two types of light changes with temperature can be provided.

Further, a PIN diode for performing APC control may be formed on an integrated circuit substrate on which the first and second photodiodes are formed. In this case, it is preferable that the configuration of the prism is changed so that a part of the emitted light on the front side of the first and second laser diodes is extracted and coupled to the PIN diode. Reading of the reproduction signal, tracking, and focus error signal may be performed as described with reference to FIG.

Further, the reflecting film 54 of the prism 20 described above is used.
Can be increased or decreased when the temperature of a laser beam of one wavelength changes, and decreased or increased when the temperature of a laser beam of another wavelength changes. Even if it changes, the reflectance need not change. In addition to such a change in the reflectance of the optical film, even if the optical means such as the optical film is configured to have a physical property that causes a change in transmittance (increase or decrease in transmittance) when the temperature rises, Similarly, the temperature characteristics can be offset. In this case, the optical means may be, for example, a light-transmitting plate or the like having the above-mentioned physical properties arranged in an optical path, or may be a light-transmitting plate formed with an optical film having the above-mentioned physical properties.

As shown in FIG. 13, the laser diodes 14 (LD1) and 15 (LD2) are separately (ie,
It may be a laser coupler 1b which is manufactured discretely and mounted.

In addition, the pattern and layout of the photodiode may be variously changed, and a detector structure other than the diode may be used.

[0133]

As described above, according to the present invention, the reflectance or transmittance of at least one outgoing light of the plurality of light emitting elements changes with temperature (for example, the reflectivity increases when the temperature rises). Since the optical means such as a reflective film is provided in the optical path between the plurality of light-emitting elements and the plurality of light-receiving elements, even if a plurality of light-emitting elements different from each other are used, the other of the emitted light For a light emitting element that emits outgoing light, when an end face protective film or the like is set so as to offset the temperature characteristics of the monitoring element against changes in physical properties of the outgoing light (for example, an increase in wavelength when the temperature rises). However, for the light emitting element that cannot be offset by this, the optical means such as the optical film provided on the end face of the prism and the like have physical properties such as increasing the reflectance when the temperature rises. It is possible to offset the temperature characteristics Te. Therefore, even when a plurality of light emitting elements are used, the degree of freedom in adjusting physical properties such as arbitrary wavelengths is increased, and stable output characteristics can always be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a laser coupler according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the same prism.

FIG. 3 is a graph showing various wavelength dependences of a reflection film of a prism.

FIG. 4 is a perspective view of a laser coupler package according to the first embodiment;
FIG. 3B is a perspective view of the same laser coupler.

FIG. 5 is a plan view of a main part of the photodiode (a) and FIG.
It is a block diagram (b) for explaining a PD method.

FIG. 6 is a perspective view of a main part of the laser diode.

FIG. 7 is a plan view (a) of a main part showing a laser beam emission direction of the laser diode, and a sectional view (b) in a direction perpendicular to the emission direction.

FIG. 8 is a cross-sectional view showing a method for manufacturing the laser diode in the order of steps.

FIG. 9 is a cross-sectional view showing a method for manufacturing the laser diode in the order of steps.

FIG. 10 is a cross-sectional view showing a method for manufacturing the laser diode in the order of steps.

FIG. 11 is a schematic diagram of an optical pickup using a laser coupler.

FIG. 12 is a main part plan view of a modification of the photodiode.

13A is a perspective view of another package of the laser coupler, and FIG. 13B is a perspective view of the same laser coupler.

FIG. 14 is a schematic configuration diagram of an optical pickup according to a conventional example.

FIG. 15 is a schematic configuration diagram of an optical pickup according to another conventional example.

FIG. 16 is a schematic configuration diagram of an optical pickup already proposed by the present inventors.

FIG. 17 is a perspective view of an essential part of the laser diode.

FIG. 18 is a plan view (a) of a main part showing an emission direction of laser light of the laser diode, and a side view (b) of the main part on the same emission side.
FIG. 9C is a main part plan view (c) showing the emission direction of the laser light from another laser diode.

FIG. 19 is a plan view (a) of a main part of a photodiode and a block diagram (b) for explaining a DPD method.

FIG. 20 is a schematic sectional view of a laser coupler.

FIG. 21 shows an IV characteristic diagram (A) of the monitoring photodiode, an IV characteristic diagram thereof at the time of temperature change (B), and a temperature characteristic diagram of reflectance of a laser end face (C).

FIG. 22 is a graph showing the wavelength dependence of the reflectance of the laser end face when the same two-wavelength laser is used.

[Explanation of symbols]

1a, 1b: laser coupler, 11: integrated circuit board, 12
... PIN diode, 13 ... Semiconductor block, 14, L
D1 first laser diode, 14a monolithic laser diode, 15, LD2 second laser diode, 16 front first photodiode, 17 rear first
Photodiode, 18 ... front second photodiode,
19: rear second photodiode, 20: prism, 2
0a: Spectral surface, 51, 52: End face, 53: End face protective film,
54: reflection film, LD: laser diode, PD1, PD
2 ... photodiode, E1, E2 ... laser beam emission part,
BS: beam splitter, C: collimator, R: aperture limiting aperture for CD, ML: multi-lens, PD: photodiode, G: grating, M: mirror, O
L: objective lens, D: optical disk, L: laser beam, L1
... First laser light, L2... Second laser light, PC... Phase comparator, AD... Adder, S1a, S1b, S2a, S2b.
spot

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01S 5/022 H01S 5/022 F-term (Reference) 5D119 AA05 AA41 AA50 BA01 CA10 EC45 EC47 FA05 FA08 FA09 FA26 JA63 JA64 JA65 KA02 LB04 5F073 AA74 AB12 AB27 BA05 CA14 CB02 DA05 DA22 EA04 EA15 FA02 FA06 FA11 FA23 FA27 FA29 GA02 GA12 5F089 BA04 EA01 FA10 GA01

Claims (18)

[Claims] 1. An optical device in which a plurality of light emitting elements respectively emitting a plurality of different lights are juxtaposed in a direction intersecting a light emitting direction, and a plurality of light receiving elements respectively receiving the plurality of lights are provided. Optical means whose reflectance or transmittance for at least one outgoing light among the outgoing lights of the plurality of light emitting elements changes depending on temperature is provided in an optical path between the plurality of light emitting elements and the plurality of light receiving elements. An optical device, which is provided. 2. An optical film in which, among the light emitted from the plurality of light emitting elements, the reflectance or transmittance for one emitted light and the reflectance or transmittance for another emitted light change in opposite directions depending on temperature. The optical device according to claim 1, wherein the optical unit is provided in the optical path. 3. An optical member for guiding each of the plurality of light-emitting elements to an object to be irradiated via a spectral surface and guiding the reflected light from the spectral surface to the plurality of light-receiving elements, The optical device according to claim 2, wherein the light receiving element is configured as an optical coupler provided on a common base, and the optical film is provided on the spectral surface. 4. A light-emitting device according to claim 1, wherein the plurality of light-emitting elements emit light from the first end face as output light,
Each of the plurality of monitor lights is emitted from an end surface thereof, and has a monitoring light receiving element for detecting the monitor light in order to control the intensity of the output light. The protective film exhibiting a reflectance or a transmittance such that the temperature-dependent characteristic of the intensity and the temperature-dependent characteristic of the detection output of the monitoring light-receiving element have opposite characteristics to each other.
Is formed on the end face, the one monitor light corresponds to the one outgoing light, the reflectance or transmittance of the optical film with respect to the other outgoing light corresponding to the other monitor light changes depending on the temperature, The optical device according to claim 2, wherein a temperature dependence characteristic of the other outgoing light is canceled. 5. The optical device according to claim 1, wherein the plurality of light emitting elements emit laser beams having different wavelengths. 6. The optical device according to claim 1, wherein the optical device is configured as an optical pickup of an optical disk device. 7. A plurality of light emitting elements respectively emitting a plurality of light beams different from each other are juxtaposed in a direction intersecting a light emitting direction, and irradiate the plurality of light beams to a disc-shaped information recording medium to receive reflected lights thereof. An optical disc device provided with a plurality of light receiving elements, wherein, among the light emitted from the plurality of light emitting elements, an optical unit whose reflectance or transmittance with respect to at least one outgoing light changes according to temperature is provided by the plurality of light emitting elements. An optical disk device, which is provided in an optical path between the light receiving element and the plurality of light receiving elements. 8. An optical film in which a reflectance or a transmittance for one emitted light and a reflectance or a transmittance for another emitted light among the emitted lights of the plurality of light emitting elements change in opposite directions depending on temperature. The optical disk device according to claim 7, wherein the optical unit is provided in the optical path. 9. A plurality of light emitting elements and an optical member for guiding each of the emitted light to an optical disk-shaped information recording medium via a spectral surface and guiding the reflected light from the spectral surface to the plurality of light receiving elements. 9. The optical disc device according to claim 8, wherein the light receiving element includes an optical coupler provided on a common base, and the optical film is provided on the spectral surface. 10. The intensity of the output light is controlled by emitting the plurality of lights as output light from a first end face of the plurality of light emitting elements and emitting a plurality of monitor lights from a second end face. A monitor light-receiving element for detecting the monitor light, and the temperature-dependent characteristic of the intensity of one monitor light of the plurality of monitor lights and the temperature-dependent characteristic of the detection output of the monitor light-receiving element. Protective films exhibiting a reflectance or a transmittance having mutually opposite characteristics are formed on the second end face, and the one monitor light corresponds to the one outgoing light and the other monitor light corresponds to the other monitor light. 9. The optical disc device according to claim 8, wherein a reflectance or a transmittance of the optical film with respect to the outgoing light changes depending on a temperature, and a temperature-dependent characteristic of the other outgoing light is offset. 11. The optical disc device according to claim 7, wherein said plurality of light emitting elements emit laser beams having different wavelengths from each other. 12. An optical device provided with a light-emitting element for emitting predetermined light and a light-receiving element for receiving the emitted light, wherein the optical means whose reflectance or transmittance for the emitted light changes with temperature is provided. An optical device provided in an optical path between the light emitting element and the light receiving element. 13. The light-receiving element, an optical member for guiding the emitted light to an irradiation target via a spectral surface and guiding the reflected light from the spectral surface to a light-receiving element, and the light-receiving element are common. 13. The optical device according to claim 12, wherein the optical device is configured as an optical coupler provided on a base, and an optical film serving as the optical unit is provided on the spectral surface. 14. The light emitting device emits the predetermined light as output light from a first end face and emits monitor light from a second end face, and outputs the monitor light to control the intensity of the output light. A protective film having a monitoring light receiving element for sensing, and exhibiting a reflectance or a transmittance such that the temperature dependency of the intensity of the monitor light and the temperature dependency of the detection output of the monitoring light receiving element are opposite to each other. The optical device according to claim 1, wherein is formed on the second end surface. 15. The optical device according to claim 12, wherein the optical device is configured as an optical pickup of an optical disk device. 16. An optical disc apparatus provided with a light emitting element for emitting predetermined light and a light receiving element for irradiating the light emission to a disk information recording medium and receiving the reflected light, An optical disk device, wherein an optical unit whose transmittance or transmittance changes with temperature is provided in an optical path between the light emitting element and the light receiving element. 17. The light-emitting element, an optical member for guiding the emitted light to the disc-shaped information recording medium via the spectral surface and guiding the reflected light from the spectral surface to the light-receiving element, and the light-receiving element 17. The optical disk device according to claim 16, wherein (a) and (b) are configured as an optical coupler provided on a common base, and an optical film as said optical means is provided on said spectral surface. 18. The light emitting device emits the predetermined light as output light from a first end face and emits monitor light from a second end face, and outputs the monitor light to control the intensity of the output light. A protective film having a monitoring light receiving element for sensing, and exhibiting a reflectance or a transmittance such that the temperature dependency of the intensity of the monitor light and the temperature dependency of the detection output of the monitoring light receiving element are opposite to each other. 17. The optical disk device according to claim 16, wherein is formed on the second end surface.