JP2003043256A - Polarization separation element and laser unit light source - Google Patents

Abstract

(57) [Problem] To provide a polarization beam splitter capable of simplifying, miniaturizing, and reducing the cost of an optical system. SOLUTION: A polarization separation element 30 is a borosilicate crown optical glass (BK7) substrate 3 which is an optically isotropic substrate.
An organic film 32 having optical anisotropy is formed on the surface of the organic film 1.
3 and a material that is optically transparent and has the same refractive index as the ordinary or extraordinary ray refractive index of the optically anisotropic film is embedded in the concave portion of the diffraction grating 33. And a quarter of the light output side of the diffraction grating 33.
This is an element formed by forming the wavelength plate 34. An optical element 40 capable of changing the angle of divergence of laser light from the semiconductor laser 10 is formed integrally with the polarization splitting element 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarization splitting element for use in an optical pickup optical system and for splitting the polarization of incident light according to the polarization direction thereof, and a laser unit light source using the same.

[0002]

2. Description of the Related Art In recent years, optical pickup devices for various optical recording media have been researched and developed. For example, a CD (Compact Disc) using a laser beam having an oscillation wavelength of 780 nm.
c) system reading optical pickup device and writing optical pickup device with an oscillation wavelength of 660n
DVD (Digital Video Dis
c) An optical pickup device for reading and an optical pickup device for writing. Further, in order to cope with future high-density optical discs, research and development of optical disc pickup devices using blue laser light have been actively conducted.

Each of the above-mentioned optical pickup devices has individual technical problems, but has common problems such as miniaturization of the pickup portion and cost reduction. There is active development for these issues.

An optical system using a polarization hologram element as a polarization separation element is adopted as an effective means for coping with downsizing and cost reduction of the optical pickup device. This is an element for separating the forward and backward paths of laser light. According to this optical system, it is possible to reduce the size of the part where the optical system is large due to the use of the polarization beam splitter and the like, and it is possible to arrange the signal detection element on the same surface as the laser emitting part of the laser light source. Therefore, there is an advantage that the optical path can be easily designed and the number of parts can be reduced.

Further, in the optical system using the polarization hologram element, the optical path can be made common even when a single optical pickup device writes and reads a plurality of types of recording media having different recording densities. , Is considered to be an effective optical system.

An optical pickup device using this polarization hologram element is disclosed in Japanese Unexamined Patent Publication No. 2000-132862 (hereinafter referred to as Publication 1) and Japanese Unexamined Patent Publication No. 2000-1234.
No. 03 (hereinafter, referred to as Publication 2) and Japanese Patent Laid-Open No. 2000
The one described in Japanese Patent Publication No. 11443 (hereinafter, referred to as Publication 3) is known.

According to the publication 1, the double wavelength holographic laser module, which is composed of a holographic optical element (HOE), a photodetector, and a laser light source for generating laser light having two kinds of wavelengths, so-called optical pickup optics. Depending on the system, it is possible to read the record information of optical disks having different recording densities such as CD and DVD.
Further, by using the double wavelength holographic laser module, the optical system is simplified, and the optical system is downsized and the cost is reduced.

Further, in the publication 2, the optical system in which the first diffraction grating is provided on one surface of the transparent plate-shaped member (so-called optical member) and the second diffraction grating is provided on the other surface is provided. By adopting this, the first diffraction grating that transmits the light having the first wavelength and diffracts the light having the second wavelength and the light having the first wavelength are diffracted, and the second wavelength is A polarization hologram element corresponding to two types of wavelengths is realized by using the second diffraction grating that transmits the light that it has. As a result, the size and efficiency of the optical pickup device are reduced.

Further, in the publication 3, the laser light from the semiconductor laser chip is emitted in a direction parallel to the light receiving surface of the light receiving element, and the emitted laser light is transmitted to the polarization hologram and the composite prism. Light is received by the light receiving element via the optical module device, thereby realizing a thin optical module device.

As described above, conventionally, by using the polarization hologram element as described in each of the above-mentioned publications, the optical pickup device can be downsized and reduced in cost, and the optical pickup device corresponding to two kinds of wavelengths can be provided. Making it feasible.

[0011]

By the way, when further downsizing, cost reduction, and thinning of each of the above-mentioned conventional optical pickup devices are advanced, the load on the polarization hologram element becomes large. For example, there is a method of reducing the thickness by narrowing the pitch of the diffraction grating portion of the polarization hologram element (narrowing the pitch of the grating) to increase the diffraction angle. However, in the above-mentioned publications 1 to 3, the following problems occur.

[0012] In the publication 1, the pitch of the diffraction grating portion of the polarization hologram element must be narrowed in order to reduce the thickness, but the yield in manufacturing the polarization hologram element decreases, and As a result, the polarization hologram element may become expensive.

That is, even if the pitch of the diffraction grating portion is narrowed, the laser light having a predetermined divergence angle from the laser light source is directly incident on the polarization hologram element. Therefore, in order to irradiate the laser beam with the laser diameter, a diffraction grating portion with a narrow pitch, that is, a region of the polarization hologram element is required. This means that the good quality of the polarization hologram element at the time of processing requires that the diffraction grating is processed normally. However, assuming that the defect probability in the wafer is N%, for example, the diffraction grating area of one chip is large. In that case, it means that the failure probability of the one chip increases. Therefore, the yield at the time of manufacturing the polarization hologram element may decrease, and the polarization hologram element may become expensive.

Further, in the above publication 2, in forming the diffraction gratings on both sides of the transparent plate-like member and narrowing the pitch of the two diffraction gratings in order to reduce the thickness,
Since these diffraction gratings are present in a difficult region for manufacturing the polarization hologram element, it takes time to manufacture the polarization separation element, and as a result, the polarization hologram element becomes expensive.

Further, according to the publication 3, the optical components such as the prism and the wave plate must be added in the housing of the optical module device in order to reduce the thickness, and therefore not only the number of components is increased. As a result, the number of steps involved in assembling the optical module in the housing is increased, and thus the optical module device becomes expensive.

As described above, the optical pickup devices described in the above publications have a low cost and a simple structure.
The reality is that neither a polarization splitting element nor a laser unit light source for the optical pickup optical system has been realized for realizing an optical pickup optical system that is thin.

The present invention has been made in view of the above, and a first object of the present invention is to provide a polarization separation element capable of simplifying an optical system, downsizing it, and reducing its cost. .

A second object of the invention is to provide a polarization beam splitting element which can reduce the cost by simplifying the assembly process of the optical system.

A third object of the invention is to provide a laser unit light source which can be reduced in cost and size by using a polarization separation element whose cost and size are reduced.

[0020]

[Means for Solving the Problems] In order to solve the above problems,
In order to achieve the first and second objects, the polarization separation element according to the invention of claim 1 is characterized in that the surface of an optically anisotropic film formed on an optically isotropic substrate has a polarization property. In a polarization splitting element having a diffraction grating, the angle of divergence of laser light emitted from a laser light source is changed on the incident surface side of its own element, and the laser light having the divergence angle after this change is incident on the side. It is characterized in that the optical element for emitting to the surface side is formed in an integrated state.

According to the first aspect of the present invention, the optical element capable of changing the angle of divergence of the incident laser light changes the angle of divergence of the laser light emitted from the laser light source. Since the laser beam with the changed divergence angle is emitted to the incident surface side of the polarization separation element, the divergence angle of the laser beam emitted from the laser light source is smaller than the divergence angle of the laser light emitted from the laser light source. A laser beam having an angle, which has a smaller laser diameter due to a smaller divergence angle, can be incident. Therefore, the size of the polarization separation element can be reduced by the reduction in the laser diameter of the laser beam applied to the diffraction grating of the polarization separation element.

According to a second aspect of the present invention, there is provided the polarization separation element, wherein the optical element corresponds to the laser light source in a one-to-one relationship.

According to the second aspect of the present invention, after the laser light emitted from the laser light source has its divergence angle changed by an optical element corresponding to the laser light source in a one-to-one relationship. Since the light is incident on the polarization separation element, the polarization separation element has a divergence angle smaller than the divergence angle of the laser light emitted from the laser light source, and the divergence angle becomes smaller. Due to this, it is possible to make a laser beam having a smaller laser diameter enter. Therefore, it is possible to limit the required area of the polarization separation element and reduce the size of the polarization separation element.

The polarization separating element according to the invention of claim 3 is characterized in that the optical element is formed in a cylindrical shape.

According to the third aspect of the invention, since the divergence angle of the incident laser light with respect to one axial direction is changed by the cylindrical optical element, the laser beam source is used as the polarization separation element. The laser light having a divergence angle smaller than the divergence angle of the laser light emitted from the laser light having a smaller laser diameter due to the smaller divergence angle is made incident. be able to.

The polarization splitting element according to the invention of claim 4 is characterized in that the optical element is formed into a convex curvature shape in the incident direction of the laser light.

According to the fourth aspect of the present invention, the divergence of the incident laser light in the biaxial directions is expanded by the optical element formed in a convex curvature shape in the incident direction of the incident laser light. Since the angle is changed, the polarization separation element has a divergence angle smaller than the divergence angle of the laser light emitted from the laser light source, and the divergence angle becomes smaller. Laser light having a reduced laser diameter due to this can be made incident.

According to a fifth aspect of the present invention, there is provided the polarization beam splitting element, wherein the optical element is formed in a toric shape.

According to the invention of claim 5, the divergence angle of the incident laser light with respect to the biaxial directions is independently changed by the toric optical element.
The polarization beam splitter has a divergence angle smaller than the divergence angle of the laser light emitted from the laser light source, and the laser diameter is small due to the divergence angle becoming smaller. The laser light can now be made incident.

The polarization separating element according to a sixth aspect of the present invention is characterized in that the optical element is formed on the incident surface side of the optically isotropic substrate.

According to the invention of claim 6, the optical element is formed integrally with the optically isotropic substrate, so that a smaller optical element can be realized, and
Due to the shortened optical path length between this optical element and the polarization separation element having the optically isotropic substrate, the laser diameter of the laser light incident on the polarization separation element can be further reduced.

In the polarization beam splitting element according to a seventh aspect of the present invention, a regulating means for regulating the distance from the laser light source is provided on the incident surface side of the optically isotropic substrate. It is characterized by

According to the invention described in claim 7, since the distance between the incident surface of the optically isotropic substrate and the laser light source is regulated by the regulating means, the optically isotropic substrate is obtained. The optical element and the laser light source integrated with each other can be easily positioned, and a desired distance between them can be maintained.

In the polarization beam splitting element according to the invention described in claim 8, the distance between the incident surface side of the optically isotropic substrate and the light receiving element for receiving the light diffracted by the diffraction grating is regulated. It is characterized in that a regulation means for controlling the operation is provided.

According to the eighth aspect of the invention, the distance between the incident surface of the optically isotropic substrate and the light receiving element is regulated by the regulating means, so that the optically isotropic substrate is provided. It is easy to position the optical element and the light receiving element integrated with each other, and it is possible to maintain a desired distance between them.

According to a ninth aspect of the present invention, there is provided a polarized light separating element, wherein the light receiving element is brought into contact with the regulating means.

According to the ninth aspect of the invention, since the light receiving element is brought into contact with the regulating means, the distance between the incident surface of the optically isotropic substrate and the light receiving element can be more accurately measured. Can be maintained.

In order to solve the above problems and to achieve the third object, a laser unit light source according to the invention of claim 10 is a laser light source for emitting linearly polarized laser light, and the laser light source. Polarization that forms a polarizing diffraction grating on the surface of the optically anisotropic film formed on the optical isotropic substrate provided on the optical path formed between The separation element is interposed between the laser light source and the polarization separation element to change the angle of divergence of the laser light emitted from the laser light source, and the laser light having the divergence angle after the change is polarized. It is characterized in that it is provided with an optical element that emits to a separation element and a light receiving element that receives the reflected light from the laser beam irradiation target diffracted by the polarization separation element.

According to the tenth aspect of the invention, between the laser light source and the polarization separation element provided on the optical path formed between the laser light source and the laser light irradiation target, Since an optical element that can change the divergence angle of the laser light is interposed, the laser beam having a divergence angle smaller than the divergence angle of the laser light emitted from the laser light source is included in the polarization separation element. In addition, it is possible to make the laser light having a smaller laser diameter due to the smaller divergence angle enter. Therefore, the size of the polarization separation element can be reduced by the reduction of the laser diameter of the laser beam with which the diffraction grating of the polarization separation element is irradiated, and the laser unit light source can be reduced accordingly.

A laser unit light source according to an eleventh aspect of the present invention is provided on a laser light source for emitting linearly polarized laser light and on an optical path formed between the laser light source and the laser light irradiation target. It has a polarization separation element according to any one of claims 1 to 9, and a photo acceptance unit which receives the catoptric light from the laser beam irradiation object diffracted by the polarization separation element. .

According to the eleventh aspect of the present invention, the polarized light separation according to any one of the first to ninth aspects is provided on the optical path formed between the laser light source and the laser light irradiation target. Since the optical element that can change the angle of divergence of the laser light from the laser light source is interposed between the element and the laser light source, the divergence angle of the laser light emitted from the laser light source is A laser beam having a divergence angle smaller than the angle and having a smaller laser diameter due to the smaller divergence angle can be incident. Moreover, since the optical element is integrated with the polarization separation element, the laser diameter of the laser light incident on the polarization separation element can be further reduced due to the shortened optical path length between these components. It will be possible. Therefore, the polarization beam splitting element can be downsized by the reduction in the laser diameter of the laser beam applied to the polarization beam splitting element, and the laser unit light source can be downsized accordingly.

A twelfth aspect of the laser unit light source according to the present invention is characterized in that the laser light source is composed of a plurality of laser light sources which oscillate lights having different oscillation wavelengths.

According to the twelfth aspect of the invention, the plurality of laser light sources oscillate laser beams having different oscillation wavelengths.

A laser unit light source according to a thirteenth aspect of the present invention is characterized in that the laser light source is composed of one laser light source capable of oscillating a plurality of lights having different oscillation wavelengths.

According to the thirteenth aspect of the invention, one laser light source oscillates light having different oscillation wavelengths.

A laser unit light source according to a fourteenth aspect of the present invention is characterized in that the laser light source is a semiconductor laser light source.

According to the fourteenth aspect of the invention, the laser light source is a semiconductor laser light source.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a polarization separation element and a laser unit light source according to the present invention will be described in detail below with reference to the accompanying drawings.

(Embodiment 1) FIGS. 1A and 1B are side views showing the structure of a laser unit light source according to Embodiment 1 of the present invention, and FIG. It is the AA line side view in a).

In FIG. 1A, a laser unit light source 1 includes a semiconductor laser 10 as a laser light source,
A light receiving element 20 capable of receiving the signal light, a polarization separation element (polarization hologram element) 30 capable of separating the laser light according to the polarization direction of the laser light, and a polarization separation element 3
Optical element 40 formed integrally with 0 and capable of changing (controlling) the divergence angle of laser light, and high part 50
A step portion composed of A and the lower portion 50B is formed, and is composed of the mounting substrate 50 on which the semiconductor laser 10 and the light receiving element 20 can be mounted.

The semiconductor laser 10 is a semiconductor laser capable of emitting laser light having a central wavelength (oscillation wavelength) of 785 nm, and is mounted on the side surface 50C between the high portion 50A and the low portion 50B of the mounting substrate 50. Has been done. In the first embodiment, as shown in FIG. 2, the semiconductor laser 10 is mounted such that its laser emitting portion (end surface of the active layer) 11 has the same height as the height 50A of the mounting substrate 50. There is.

The light receiving element 20 is composed of a photodiode made of silicon. In the first embodiment, as shown in FIG. 2, the light receiving surface 21 thereof has the same height as the height 50A of the mounting substrate 50. It is implemented to be

In the polarization separation element 30, an organic film 32 having optical anisotropy is formed on a borosilicate crown optical glass (hereinafter referred to as BK7) substrate 31 which is an optically isotropic substrate, and this organic film 32 is formed. A concave-convex periodic structure, that is, a diffraction grating 33 (hatched portion) is formed on the surface of, and the concave portion of this diffraction grating 33 is refracted in the ordinary ray direction of an optically anisotropic film whose refractive index is optically transparent. In this element, a material having the same refractive index or the refractive index in the extraordinary ray direction is embedded, and a quarter wavelength plate 34 is formed on the light emitting side of the diffraction grating 33.

The refractive index of the organic film 32 is 1.58 and 1.6.
9 and the refractive index difference is 0.11. In the diffraction grating 33, the grating pitch is 2 μm and the grating depth is 3 μm. The material embedded in the recess (grating) of the diffraction grating 33 is an acrylic ultraviolet curing resin,
The refractive index is 1.58.

The diffraction grating 33 is arranged so that there is no difference in refractive index in the polarization direction of the laser light from the semiconductor laser 10 and the laser light is transmitted therethrough. Therefore, the polarization separation element 30 separates the polarization of the incident laser light using the polarization diffraction grating 33. That is, the polarized light is separated by changing the transmittance and the diffraction efficiency according to the light of two polarization directions orthogonal to each other. From this, it can be said that the polarization separation element 30 is an element capable of defining the optical path according to the polarization direction of the polarized light.

The optical element 40 has a curvature of 0.75 m on one side.
It is composed of a cylindrical lens of m and a thickness of 0.5 mm, and is formed on the incident surface of the BK7 substrate 31. The incident surface of the optical element 40 is the semiconductor laser 10
It is arranged at a position 1 mm away from the laser emitting portion (end face of the active layer) 11. Further, since the optical element 40 has a cylindrical shape,
One axis direction of the incident laser light (Y-axis direction or X-axis direction)
Change the divergence angle with respect to (axial direction).

Further, the optical element 40 and the polarization separation element 30
The (diffraction grating 33) and the collimator lens 60 are arranged on an optical path formed between the semiconductor laser 10 and an optical recording medium, such as an optical disk, as a laser light irradiation target.

In FIGS. 1 (a) and 1 (b), reference numeral 70A represents a laser beam traveling with a vertical spread angle (θ⊥), and reference numeral 70 represents a vertical spread angle (θ) after passing through the optical element 40. ⊥) represents the traveling laser light, and the reference numeral 80 indicates the laser light 70, 70A and the polarization direction 9
It represents a laser beam traveling with a horizontal divergence angle (θ //) that is different by 0 degree.

By the way, in the first embodiment, the optical element 40 capable of changing the divergence angle of the laser beam on the BK7 substrate (optically isotropic substrate) 31 of the polarization separation element 30.
A cylindrical laser as a semiconductor laser 10
The reason why they are made to correspond to each other in a one-to-one relationship and are formed integrally is to suppress (decrease) the divergence angle of the laser light incident on the polarization separation element 30.

Here, regarding the merit of suppressing (decreasing) the angle of divergence of the laser light, the case where the optical element 40 does not exist and the case where the optical element 40 is integrated with the polarization separation element 30 as in the first embodiment. The description will be given by taking the case where it is realized as an example.

FIG. 3A is a side view showing the structure of the laser unit light source 1A when the optical element 40 is not present. This laser unit light source 1A is the laser unit light source 1 shown in FIG. In the above configuration, the optical element 40 is removed and the polarization separation element 30 is replaced with the polarization separation element 30.
The configuration is changed to A. In FIG.
The same code | symbol shall be attached | subjected to the part which performs the same function as the component shown to (a). The polarization separation element 30A has the same configuration as the polarization separation element 30. Incidentally, reference numeral 31A is a BK7 substrate, reference numeral 32A is an organic film, reference numeral 33A is a diffraction grating (hatched portion),
Reference numeral 34A is a quarter-wave plate. 3 (b) is shown in FIG.
It is a BB line side view in (a).

In FIGS. 3 (a) and 3 (b), reference numeral 70A represents a laser beam traveling with a vertical spread angle (θ⊥), and reference numeral 80A represents a horizontal spread having a polarization direction different from that of the laser light 70A by 90 degrees. It represents a laser beam traveling at an angle (θ //).

In the laser unit light source 1A, the divergence angle of the laser light from the semiconductor laser 10 is as shown in FIG.
As in the laser beam shown in (a), the vertical spread angle (θ
The angle ⊥) is 25 degrees, while the horizontal spread angle (θ //) is 10 degrees as in the laser beam shown in FIG. 3B. Therefore, in FIGS. 3 (a) and 3 (b),
The laser light in the portion of (the diffraction grating 33A of) the polarization separation element 30A has a laser diameter of 2.2 mm diameter × 0.
It has an elliptical shape with a size of 9 mm.

On the other hand, when the cylindrical lens as the optical element 40 is integrated with the polarization separation element 30 as in the laser unit light source 1 shown in FIGS. 1A and 1B, the polarization separation element 30 is used. Since the angle of divergence of light incident on the laser beam can be suppressed (decreased), the laser beam at (the diffraction grating 33 of) the polarization separation element 30 has a laser diameter of 1.3 mm diameter × 0.9 mm diameter. It becomes possible to make an elliptical shape having a size of.

Therefore, the optical element 40 is replaced with the polarization separation element 30.
When it is integrated with the optical element 4, the divergence angle of the laser beam can be suppressed (decreased).
Compared to the case where 0 does not exist, the required polarization separation element 3
There is an advantage that the size of 0 can be reduced.

Next, the operation of the above laser unit light source 1 will be described. Here, a case where the laser unit light source 1 is used for an optical disc pickup will be described as an example.

The laser light emitted from the semiconductor laser 10 passes through the optical element 40 and enters the diffraction grating 33 of the polarization separation element 30. Since the diffraction grating 33 has no refractive index difference in the polarization direction of the incident laser light and is arranged so that the laser light is transmitted,
The laser light passes through the polarization separation element 30 as it is. At that time, the polarization state is converted from linearly polarized light to circularly polarized light by the quarter-wave plate 34 integrated with the polarization separation element 30. The laser beam that has passed through the polarization separation element 30 enters the collimator lens 60, then passes through an optical system such as an objective lens, and is irradiated onto an optical recording medium such as an optical disk.

Then, the reflected light showing the information on the irradiation position of the optical recording medium is incident on the collimator lens 60 again through the optical system such as the objective lens. The reflected light that has entered the collimator lens 60 again has the polarization separating element 30 again.
And is converted by the quarter-wave plate 34 from circularly polarized light into linearly polarized light. At that time, the linearly polarized light has a polarization direction rotated by 90 degrees with respect to the polarization direction of the linearly polarized light emitted from the semiconductor laser 10. Therefore, in the polarization separation element 30, the optical path is changed due to the occurrence of diffraction, and the linearly polarized light incident on the polarization separation element 30 is guided to the light receiving element 20. Then, the light receiving element 20 receives the linearly polarized light as signal light, whereby the information on the optical recording medium can be read.

In the first embodiment, the optical element 4
Although 0 is integrated with the polarization separation element 30,
The present invention is not limited to this, and the semiconductor laser 1
The optical element 40 may be independently interposed between 0 and the polarization separation element 30. In this case also, since the optical element 40 can change (control) the divergence angle of the laser light from the semiconductor laser 10, the polarization separation element 3
It is possible to suppress (decrease) the divergence angle of the laser light incident on 0.

As described above, according to the first embodiment, the following operational effects (1) to (5) can be obtained.

(1) When the optical element 40 is interposed between the semiconductor laser 10 and the polarization beam splitting element 30, the spread of the laser beam incident on the polarization beam splitting element 30 is wider than that when the optical element is not present. The angle can be suppressed (decreased), and the size of the laser diameter of the laser beam at (the diffraction grating 33 of) the polarization separation element 30 can be reduced. Therefore, the required size of the polarization separation element 30 can be reduced.

(2) In particular, when the optical element 40 is integrated with the polarization beam splitting element 30, the polarization beam splitting element 30 is provided with an optical element 40 as compared with the case where the optical element 40 is provided independently immediately before the polarization beam splitting element 30. Although the divergent angles of the incident laser light are the same, the exit surface of the optical element 40 and the polarization separation element 3
The distance to the diffraction grating 33 of 0 is short,
The laser diameter of the laser light in the portion can be reduced, and the required size of the polarization separation element 30 can be further reduced. Therefore, it is preferable to integrate the optical element 40 with the polarization separation element 30 from the viewpoint of miniaturization of the polarization separation element 30.

(3) By the way, when a polarization separation element using a diffraction grating is manufactured, if the grating pitch is reduced in order to increase the diffraction angle of the element, the pitch of the element (the size of the polarization separation element This affects yield and cost, and if the grating is not formed on the entire surface used by the diffraction grating, the polarization separation element becomes defective.

However, according to the first embodiment, in the polarization separating element 30 using the diffraction grating, the grating pitch of the diffraction grating is set to 2 μm in order to increase the diffraction angle of the element, but as described above. Polarization separation element 30
Since it is possible to reduce the probability that the polarization separation element 30 is defective, it is possible to increase the number of the polarization separation elements 30 that can be taken from the wafer and reduce the cost.

That is, a good product of the polarization beam splitting element at the time of processing requires that the diffraction grating is processed normally. However, assuming that the defect probability in the wafer is N%, the diffraction grating area of one chip is large. In that case, the failure probability of the one chip increases. However, when the size of the diffraction grating region of one chip is reduced, the probability of failure of the one chip can be reduced, and the probability of taking a chip from the wafer can be increased, so that the yield can be increased. Therefore, the cost of the polarization beam splitting element can be reduced.

(4) From the above, it is possible to reduce the size and cost of the polarization beam splitting element, thereby reducing the cost of the laser unit light source. Further, by using the above-mentioned polarization separation element for the laser unit light source, it becomes possible to manufacture a laser unit light source that is smaller and less expensive.

(5) Further, by using the semiconductor laser 10 as the laser light source, the cost can be reduced as compared with the case of using a normal laser light source.

(Second Embodiment) FIGS. 4 (a) and 4 (b) are side views showing the structure of a laser unit light source 2 according to a second embodiment of the present invention, and FIG. It is a CC line side view in (a). The laser unit light source 2 shown in FIG. 4A has a configuration in which the optical element 40 is replaced with an optical element 90 in the configuration of the laser unit light source 1 shown in FIG. In the same figure, FIG.
The parts having the same functions as those of the components shown in FIG.

The optical element 90 is composed of a convex lens having a curvature of 0.75 mm and a thickness of 0.5 mm (a convex curvature shape toward the incident direction of laser light), and is integrated on the incident surface of the BK7 substrate 31. Is formed. Further, the optical element 90 is arranged such that its incident surface is separated from the laser emitting portion (end surface of the active layer) 11 of the semiconductor laser 10 by a distance of 1 mm. Further, since the optical element 90 is a convex lens, it changes the angle of divergence of the incident laser light with respect to the biaxial directions (Y-axis direction and X-axis direction).

Also in this second embodiment, a convex lens as an optical element 90 capable of changing (controlling) the divergence angle of the laser beam on the BK7 substrate (optically isotropic substrate) 31 of the polarization separation element 30. Is formed in one-to-one correspondence with the semiconductor laser 10 and is integrally formed, as in the case of the first embodiment described above.
This is for suppressing (decreasing) the divergence angle of the laser light incident on the polarization separation element 30.

Specifically, as shown in FIGS. 3A and 3B, when there is no convex lens as the optical element 90, (the diffraction grating 33 of the polarization separation element 30A is included.
The laser light in the portion A) has a laser diameter of 2.
While it has an elliptical shape with a size of 2 mm and a diameter of 0.9 mm, a convex lens as an optical element 90 like the laser unit light source 2 shown in FIGS. 4A and 4B is integrated with the polarization separation element 30. When it is made into a polarized light, the polarization separation element 30
The laser light at the (diffraction grating 33) portion has an elliptical shape with a laser diameter of 1.3 mm diameter × 0.5 mm diameter.

Therefore, when the convex lens as the optical element 90 is integrated with the polarization separation element 30, the divergence angle of the laser beam can be suppressed (decreased). Moreover, in the case of such integration, a laser beam having a diameter of 1.3 mm and a diameter of 0.9 mm when the cylindrical lens as the optical element 40 is integrated with the polarization separation element 30 as in the first embodiment. Compared to the diameter
The laser diameter can be further reduced.

Since the operation of the laser unit light source 2 according to the second embodiment is the same as that of the first embodiment,
The description is omitted here.

In the second embodiment, the optical element 9
Although 0 is integrated with the polarization separation element 30,
The present invention is not limited to this, and the semiconductor laser 1
The optical element 90 may be independently interposed between 0 and the polarization separation element 30. Also in this case, since the optical element 90 can change the angle of divergence of the laser light from the semiconductor laser 10, the angle of divergence of the laser light incident on the polarization separation element 30 can be suppressed (decreased).

As described above, according to the second embodiment, the same effects as the effects (1) to (5) of the first embodiment can be obtained. Incidentally, when the optical element 90 is interposed between the semiconductor laser 10 and the polarization separation element 30,
Compared to the case where there is no optical element, the polarization separation element 3
Suppresses the divergence angle of laser light incident on 0 (small)
The polarization separation element 30 (of which the diffraction grating 33) can be
It is possible to reduce the laser diameter of the laser light in the portion. Therefore, the required size of the polarization separation element 30 can be reduced.

When the optical element 90 is integrated with the polarization beam splitting element 30, it is the same as the case of the first embodiment as compared with the case where the optical element 90 is independently provided immediately before the polarization beam splitting element 30. For this reason, the laser diameter of the laser light in the diffraction grating 33 portion of the polarization beam splitting element 30 can be reduced, and the required size of the polarization beam splitting element 30 can be further reduced. Therefore, the optical element 9
It is preferable that 0 is integrated with the polarization separation element 30 from the viewpoint of miniaturization of the polarization separation element 30.

Further, according to the second embodiment, in addition to the above-described function and effect, when the optical element 90 which is a convex lens is integrated with the polarization separation element 30, the optical element 40 as in the first embodiment is provided. Compared with the case where the cylindrical lens is integrated with the polarization separation element 30, the laser diameter of the laser light can be further reduced, and thus the required size of the polarization separation element 30 can be further reduced. .

(Third Embodiment) FIGS. 5A and 5B are side views showing the configuration of a laser unit light source 3 according to a third embodiment of the present invention, and FIG. It is a DD line side view in (a). The laser unit light source 3 shown in FIG. 5A is the same as the laser unit light source 1 shown in FIG.
And a plurality of regulating members (regulating means) 111 are added. In the figure, the same reference numerals are given to the parts that perform the same functions as those of the components shown in FIG.

The optical element 110 is an optical element (microlens) in which a toric lens is formed on the BK7 substrate 31, and has a function of changing the light divergence angle of the laser light. The curvature of the microlens is 40 μm in the state of the optical element 110 (microlens) shown in FIG. 5A, and is 150 μm in the state of the optical element 110 (microlens) shown in FIG. 5B.
μm. Such an optical element 110 independently changes the divergence angle of the laser light from the semiconductor laser 10 with respect to the biaxial directions (Y-axis direction and X-axis direction).

The plurality of defining members 111 are the polarization separating elements 3
It is provided on the incident surface of the BK7 substrate 31 of No. 0 and is integrated with the polarization separation element 30. Multiple regulating members 1
Reference numeral 11 has a function of defining the distance between the incident surface of the BK7 substrate 31 of the polarization separation element 30 and the high portion 50A of the mounting substrate 50. This means that the plurality of defining members 111 are
The incident surface of the microlens as the optical element 110 and the laser emitting portion (end surface of the active layer) 11 of the semiconductor laser 10
It means that it has a function of defining the distance between the light receiving surface 21 of the light receiving element 20 and the incident surface of the microlens.

Further, in the plurality of defining members 111, the distance between the incident surface of the BK7 substrate 31 of the polarization separation element 30 and the high portion 50A of the mounting substrate 50 is the lens height of the microlens as the optical element 110. The length is set to a value obtained by adding the length of “0.1 mm” to the value, and is formed in the shape of a prism, for example.

Therefore, the light-receiving surface 21 of the light-receiving element 20 is releasably brought into contact with the other ends of the plurality of regulating members 111, so that the incident surface of the optical element 110 has the laser-emitting portion of the semiconductor laser 10 ( End face) 11 and light receiving element 20
The light receiving surface 21 is placed at a position separated by a distance of 0.1 mm. In addition, the light receiving surface 21 of the light receiving element 20
Is in contact with the plurality of defining members 111, the accuracy of the distance between them can be improved.

Also in the third embodiment, the microlens as the optical element 110 capable of changing the divergence angle of the laser beam is provided on the BK7 substrate 31 of the polarization separation element 30 in a one-to-one relationship with the semiconductor laser 10. The reason why they are made to correspond to each other and integrally formed is to suppress (decrease) the divergence angle of the laser light incident on the polarization separation element 30, as in the case of the first embodiment described above. is there.

Specifically, as shown in FIGS. 3A and 3B, when there is no microlens as the optical element 110, the polarization separation element 30A (diffraction grating 33A) part thereof is formed. The laser light has an elliptical shape with a diameter of 2.2 mm and a diameter of 0.9 mm, while an optical element such as the laser unit light source 3 shown in FIGS. 5A and 5B. When the microlens 110 is integrated with the polarization separation element 30, the laser beam at (the diffraction grating 33 of) the polarization separation element 30 has a laser diameter of 0.7 mm × 0.7 mm.
It becomes an elliptical shape with the size of.

As described above, when the microlens as the optical element 110 is integrated with the polarization separation element 30, the angle of divergence of laser light can be suppressed (decreased). Moreover, in the case of such integration, a laser beam having a diameter of 1.3 mm and a diameter of 0.9 mm when the cylindrical lens as the optical element 40 is integrated with the polarization separation element 30 as in the first embodiment. The laser diameter can be further reduced as compared with the diameter.

Since the operation of the laser unit light source 3 according to the third embodiment is the same as that of the first embodiment,
The description is omitted here.

In the third embodiment, the optical element 1
Although 10 is integrated with the polarization separation element 30, the present invention is not limited to this, and the optical element 110 may be independently interposed between the semiconductor laser 10 and the polarization separation element 30. You can Also in this case, since the optical element 110 can control the angle of divergence of the laser light from the semiconductor laser 10, the angle of divergence of the laser light incident on the polarization separation element 30 is suppressed (small).
can do.

As described above, according to the third embodiment, the same effects as the effects (1) to (5) of the first embodiment can be obtained. Incidentally, when the optical element 110 is interposed between the semiconductor laser 10 and the polarization beam splitting element 30, the divergence angle of the laser beam incident on the polarization beam splitting element 30 is made smaller than that in the case where no optical element is present. It can be suppressed (decreased), and the size of the laser diameter of the laser beam at (the diffraction grating 33 of) the polarization separation element 30 can be reduced. Therefore, the required size of the polarization separation element 30 can be reduced.

In particular, when the optical element 110 is integrated with the polarization separation element 30, compared with the case where the optical element 90 is independently provided immediately before the polarization separation element 30, in the case of the first embodiment. For the same reason as above, the laser diameter of the laser beam in the diffraction grating 33 portion of the polarization beam splitting element 30 can be reduced, and the required polarization beam splitting element 3 can be further reduced.
The size of 0 can be reduced. Therefore, it is preferable to integrate the optical element 110 with the polarization separation element 30 from the viewpoint of downsizing the polarization separation element 30.

Furthermore, according to the third embodiment, in addition to the above-described operational effects, the following operational effects (6) to (8) are exhibited.

(6) Since the plurality of defining members 111 are provided on the incident surface of the BK7 substrate 31 of the polarization separation element 30 and integrated with the polarization separation element 30, the optical element 110 and the laser emitting section 11 of the semiconductor laser 10 are connected to each other. Since the distance between them can be accurately determined (their positioning can be easily performed), the semiconductor laser 1
0, the polarization separation element 30 and the optical element 110 can be easily mounted on the laser unit light source 3. Therefore, the assembly process (assembly process) of the laser unit light source 3 is simplified, and the cost can be reduced.

(7) Further, since the plurality of defining members 111 are provided on the incident surface of the BK7 substrate 31 of the polarization separation element 30 and integrated with the polarization separation element 30, the light receiving surfaces 21 of the optical element 110 and the light receiving element 20 are integrated. Since it is possible to accurately determine the distance between the light receiving element 20, the polarization separation element 30, and the optical element 110, the laser unit light source 3 can be mounted. It will be easy. Therefore, the laser unit light source 3
The assembling process (assembling process) can be simplified and the cost can be reduced.

(8) Further, since the light receiving element 20 is mounted on the high portion 50A of the mounting substrate 50, and the light receiving surface 21 thereof is brought into contact with the plurality of regulating members 111 so as to receive light, the optical element 110 is provided. The distance between the light receiving element 20 and the light receiving element 20 can be accurately determined (their positioning can be easily performed), and the light receiving element 20 and the optical element 110 can be easily mounted on the laser unit light source 3. . Therefore, the assembly process (assembly process) of the laser unit light source 3 is simplified, and the cost can be reduced.

(Fourth Embodiment) FIGS. 6A and 6B are side views showing the structure of a laser unit light source 4 according to a fourth embodiment of the present invention, and FIG. It is a EE line side view in (a). A laser unit light source 4 shown in FIG. 6A has a structure in which the semiconductor laser 10 and the light receiving element 20 are removed from the configuration of the laser unit light source 1 shown in FIG.
2, a plurality of optical elements 131 and 132, and a plurality of defining members (defining means) 140 are added.
In the figure, the same reference numerals are given to the parts that perform the same functions as those of the components shown in FIG.

The semiconductor laser 121 is a semiconductor laser capable of emitting linearly polarized light having a central wavelength (oscillation wavelength) of 785 nm, while the semiconductor laser 122 is
Is a semiconductor laser capable of emitting linearly polarized light having a central wavelength (oscillation wavelength) of 660 nm. Similar to the semiconductor laser 10, these semiconductor lasers 121 and 122 are mounted on the side surface 50C between the high portion 50A and the low portion 50B of the mounting substrate 50, and the laser emitting portion (end face of the active layer) thereof. Are mounted so as to have the same height as the height 50A of the mounting substrate 50.

Each of the plurality of optical elements 131 and 132 is an optical element (microlens) in which a toric lens is formed on the BK7 substrate 31 of the polarization separation element 30, and the angle of the light divergence angle of the laser light. Has the function of changing. The optical element 131 is provided corresponding to the position where the semiconductor laser 121 is arranged.
32 is provided corresponding to the arrangement position of the semiconductor laser 122. Further, an optical element (microlens) 131,
In 132, the curvature of the microlens is as shown in FIG.
In the state of the optical elements 131 and 132 shown in FIG.
m, and 150 μm in the state of the optical elements 131 and 132 shown in FIG. 6B.

The plurality of defining members 140 have the same function and structure as the plurality of defining members 111. By the way, by bringing the other end portions of the plurality of defining members 140 into close contact with the high portion 50A of the mounting substrate 50, the optical elements 131, 132
Is the semiconductor laser 12
It is arranged at a position separated by a distance of 0.1 mm from the laser emission parts (end face) of Nos. 1 and 122.

Since the laser beam diffracted by the polarization beam splitting element 30 has a different diffraction angle (the traveling direction of the diffracted light is different) depending on its wavelength, the light receiving element 20 has a center wavelength of 785 nm or 660 nm. Is arranged so that it can receive light.

Also in the fourth embodiment, the microlenses as the optical elements 131 and 132 capable of changing (controlling) the divergence angle of the laser light are provided on the BK7 substrate 31 of the polarization separation element 30 as a semiconductor laser. 121, 1
22 is made to correspond to each other in a one-to-one relationship with 22 and to be formed integrally with each other, as in the case of the first embodiment described above, the divergence angle of the laser beam incident on the polarization separation element 30 is This is to suppress (decrease).

Specifically, as shown in FIGS. 3 (a) and 3 (b), when the microlenses as the optical elements 131 and 132 do not exist, the polarization separation element 30A.
The laser light in the (diffraction grating 33A) part has an elliptical shape with a laser diameter of 2.2 mm diameter × 0.9 mm diameter, whereas in FIGS. 6 (a) and 6 (b). Optical elements 131, 13 such as the laser unit light source 4 shown
When the respective microlenses 2 are integrated with the polarization separation element 30, (the diffraction grating 33 of the polarization separation element 30)
The laser diameter of the part is 0.7 m.
It becomes an elliptical shape with a size of m × 0.7 mm in diameter. As described above, when the microlenses as the optical elements 131 and 132 are integrated with the polarization separation element 30, the angle of the divergence angle of the laser light can be suppressed (decreased).

In the laser unit light source 4 according to the fourth embodiment, two kinds of semiconductor lasers 121,
The same operation is performed for each of the 122
When focusing on the operation with respect to one of the semiconductor lasers, it is the same as in the case of the first embodiment, and therefore its explanation is omitted here.

As described above, according to the fourth embodiment, the same operational effect as the operational effect of the third embodiment, that is, the operational effects (1) to (5) of the first embodiment and the third embodiment. The unique operational effects (6) to (8) are exhibited.

Further, according to the fourth embodiment, in addition to the above-mentioned function and effect, the following function and effect are also obtained. That is, by using two kinds of semiconductor lasers, it becomes possible to read and write even on optical disks having different recording densities, and it is possible to provide a laser unit light source having a multi-function. This means that it is possible to provide a laser unit light source that is low in cost, small in size, and multifunctional.

(Fifth Embodiment) FIGS. 7A and 7B are side views showing the structure of a laser unit light source 5 according to a fifth embodiment of the present invention, and FIG. It is a FF line side view in (a). The laser unit light source 5 shown in FIG. 7A has a configuration in which the semiconductor laser 10 is changed to a semiconductor laser 170 in the configuration of the laser unit light source 3 shown in FIG. 5A. In the figure, the same reference numerals are given to the parts that perform the same functions as the components shown in FIG.

The semiconductor laser 170 has a center wavelength (oscillation wavelength) of 785 nm and a center wavelength (oscillation wavelength) of 660 n.
m is a semiconductor laser capable of emitting linearly polarized light of two different wavelengths, and is mounted on the mounting substrate 50 in the same manner as the semiconductor laser 10.

Since the laser beam diffracted by the polarization beam splitting element 30 has a different diffraction angle (the traveling direction of the diffracted light is different) depending on its wavelength, the light receiving element 20 has a center wavelength of 785 nm or 660 nm. Is arranged so that it can receive light.

In the operation of the laser unit light source 5 of the fifth embodiment, the central wavelength of the semiconductor laser 170 is 78
The third embodiment is the same as the third embodiment except that laser oscillation of linearly polarized light of 5 nm or 660 nm is performed. Therefore, the description of the operation is omitted here.

According to the fifth embodiment, the third embodiment
In addition to the same action and effect as the above, the following action and effects are also obtained. That is, by using a semiconductor laser capable of emitting linearly polarized light of two kinds of wavelengths as a laser light source, it becomes possible to read and write even on optical discs having different recording densities, and a laser unit light source with multiple functions Can be provided. Moreover, since the multifunctionalization can be realized by using one laser light source (semiconductor laser) capable of emitting linearly polarized light of two kinds of wavelengths, the cost can be further reduced. This is compared with the case of the fourth embodiment.
This means that it is possible to provide a laser unit light source that achieves further cost reduction and size reduction, and that has multiple functions.

By the way, in each of the above-described first to fifth embodiments, the constituent elements of the laser unit light source described in each embodiment are merely examples, and the present invention is not limited thereto. For example, although the organic film is exemplified as the material of the polarization separation element, any kind of material may be used as long as the material has birefringence. Although a semiconductor laser is used as the laser light source, a solid-state laser or a second harmonic generation (SH
G) A laser can also be used.

[0120]

As described above, according to the first aspect of the invention, the optical element capable of changing the divergence angle of the incident laser light is the divergence angle of the laser light emitted from the laser light source. Is changed so that the laser light having the divergence angle after this change is emitted to the incident surface side of the polarization separation element, the polarization separation element is provided with a divergence angle of the laser light emitted from the laser light source. A laser beam having a divergence angle smaller than the angle,
Laser light having a smaller laser diameter due to the smaller divergence angle can be made incident. Therefore, the polarization beam splitting element can be made smaller by the reduction in the laser diameter of the laser beam applied to the diffraction grating of the polarization beam splitting element, and the cost of the polarization beam splitting element can be reduced accordingly. .

According to the second aspect of the invention, the laser light emitted from the laser light source has its divergence angle changed by the optical element corresponding to the laser light source in a one-to-one relationship, Since the light is incident on the polarization separation element, the polarization separation element has a divergence angle smaller than the divergence angle of the laser light emitted from the laser light source, and the divergence angle becomes smaller. Due to this, it is possible to make a laser beam having a smaller laser diameter enter. Therefore, it is possible to limit the required area of the polarization separation element and reduce the size of the polarization separation element, and accordingly reduce the cost of the polarization separation element.

According to the third aspect of the present invention, since the divergence angle of the incident laser light with respect to one axial direction is changed by the cylindrical optical element, the polarization separating element is provided with a laser light source. A laser beam having a divergence angle smaller than the divergence angle of the emitted laser beam, and having a smaller laser diameter due to the divergence angle becoming smaller. You can As a result, it is possible to limit the required region of the polarization separation element and reduce the size of the polarization separation element, and accordingly reduce the cost of the polarization separation element.

According to the fourth aspect of the invention, the divergence angle of the incident laser light in the biaxial directions is increased by the optical element formed in a convex curvature shape toward the incident direction of the incident laser light. Since the polarization separation element is a laser light having a divergence angle smaller than the divergence angle of the laser light emitted from the laser light source, the divergence angle is reduced. Then, the laser beam having the reduced laser diameter can be made incident. As a result, it is possible to further limit the required area of the polarization separation element and to reduce the size of the polarization separation element, and thus to further reduce the cost of the polarization separation element.

According to the invention described in claim 5, since the divergence angle of the incident laser light with respect to the biaxial directions is independently changed by the toric-shaped optical element, the laser beam source is used as the polarization separation element. The laser light having a divergence angle smaller than the divergence angle of the laser light emitted from the laser light having a smaller laser diameter due to the smaller divergence angle is made incident. be able to. As a result, it is possible to limit the required region of the polarization separation element and reduce the size of the polarization separation element, and accordingly reduce the cost of the polarization separation element.

According to the sixth aspect of the invention, since the optical element is formed integrally with the optically isotropic substrate, a smaller optical element can be realized, and this optical element is also realized. Due to the shortened optical path length between the polarization separation element having the optically isotropic substrate and the polarization separation element, the laser diameter of the laser light incident on the polarization separation element can be further reduced. Therefore, the polarization beam splitting element can be made smaller by the reduction in the laser diameter of the laser beam applied to the diffraction grating of the polarization beam splitting element, and the cost of the polarization beam splitting element can be reduced accordingly. .

According to the invention described in claim 7, since the distance between the incident surface of the optically isotropic substrate and the laser light source is regulated by the regulating means, the optically isotropic substrate can be used. The integrated optical element and the laser light source can be easily positioned, and since the positioning is easy, the laser light source and the optical element can be easily mounted. As a result, the assembly process of the laser unit light source is simplified and the cost can be reduced.

According to the eighth aspect of the invention, since the distance between the incident surface of the optically isotropic substrate and the light receiving element is regulated by the regulating means, the optically isotropic substrate is used. The integrated optical element and the light receiving element can be easily positioned, and since the positioning is easy, the light receiving element and the optical element can be easily mounted. As a result, the assembly process of the laser unit light source is simplified and the cost can be reduced.

According to the invention described in claim 9, since the light receiving element is brought into contact with the regulating means, the distance between the light receiving element and the incident surface of the optically isotropic substrate can be maintained more accurately. can do.

According to the invention described in claim 10, between the laser light source and the polarization separation element provided on the optical path formed between the laser light source and the laser light irradiation target,
Since the optical element that can change the angle of divergence of the laser light from the laser light source is interposed, the divergence angle of the laser light emitted from the laser light source is smaller than the angle of divergence of the laser light emitted from the laser light source. It is possible to make the laser light having the laser diameter smaller due to the smaller divergence angle. Therefore, the polarization beam splitting element can be made smaller by the reduction in the laser diameter of the laser beam applied to the diffraction grating of the polarization beam splitting element, and the cost of the polarization beam splitting element can be reduced accordingly. . Therefore, it is possible to provide a laser unit light source that is downsized and reduced in cost.

According to the eleventh aspect of the invention, the polarization beam splitting element according to any one of the first to ninth aspects is provided on the optical path formed between the laser light source and the laser light irradiation target. Since the optical element that can change the angle of divergence of the laser light from the laser light source is interposed between the laser light source and the A laser beam having a smaller divergence angle than that of the laser beam having a smaller laser diameter due to the smaller divergence angle can be incident. Moreover, since the optical element is integrated with the polarization separation element,
Due to the shortened optical path length between these constituent elements, it is possible to further reduce the laser diameter of the laser light incident on the polarization separation element. Therefore, the polarization beam splitting element can be made smaller by the reduction in the laser diameter of the laser beam applied to the diffraction grating of the polarization beam splitting element, and the cost of the polarization beam splitting element can be reduced accordingly. . Therefore, it is possible to provide a laser unit light source that is downsized and reduced in cost.

According to the twelfth aspect of the present invention, since the plurality of laser light sources oscillate laser beams having different oscillation wavelengths, it becomes possible to read and write to media having different recording densities. It is possible to provide a laser unit light source that has multiple functions.

According to the thirteenth aspect of the invention, since one laser light source oscillates light having a plurality of different oscillation wavelengths, it becomes possible to read and write to media having different recording densities, It is possible to provide a laser unit light source that has multiple functions. Moreover,
The multi-functionalization can be realized by using one laser light source capable of emitting linearly polarized light of two kinds of wavelengths, so that it is possible to provide a laser unit light source with further reduced cost.

According to the fourteenth aspect of the invention, since the laser light source is the semiconductor laser light source, the cost of the laser light source can be reduced and the cost of the laser unit light source can be reduced.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of a laser unit light source according to a first embodiment.

FIG. 2 is a diagram showing how a semiconductor laser and a light receiving element are mounted on a mounting substrate.

FIG. 3 is a diagram for explaining the characteristics of the laser unit light source according to the first embodiment.

FIG. 4 is a side view showing a configuration of a laser unit light source according to a second embodiment.

FIG. 5 is a side view showing a configuration of a laser unit light source according to a third embodiment.

FIG. 6 is a side view showing a configuration of a laser unit light source according to a fourth embodiment.

FIG. 7 is a side view showing a configuration of a laser unit light source according to a fifth embodiment.

[Explanation of symbols]

1,2,3,4,5 laser unit light source 10,121,122,170 Semiconductor laser 20 Light receiving element 30 Polarization separation element 40, 90, 110, 131, 132 Optical element 50 mounting board 60 collimating lens 111,140 Regulation member

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01S 5/40 H01S 5/40 F term (reference) 2H049 AA03 AA13 AA43 AA57 AA68 BA05 BA42 BA47 BB03 BB62 BC08 BC09 BC21 5D119 AA01 AA41 BA01 BB01 EB03 EC45 EC47 FA05 FA08 JA06 JA08 JA12 JA32 5F073 AB27 BA04 EA04 FA06 FA11

Claims (14)

[Claims] 1. A polarization beam splitting device in which a polarizing diffraction grating is formed on the surface of an optically anisotropic film formed on an optically isotropic substrate, wherein a laser is provided on the incident surface side of its own device. The divergence angle of the laser light emitted from the light source is changed, and an optical element for emitting the laser light having the changed divergence angle to the incident surface side is formed in an integrated state. And a polarization separation element. 2. The polarization separation element according to claim 1, wherein the optical element corresponds to the laser light source in a one-to-one relationship. 3. The polarization separation element according to claim 1, wherein the optical element is formed in a cylindrical shape. 4. The polarization beam splitting element according to claim 1, wherein the optical element is formed in a convex curvature shape in the incident direction of the laser light. 5. The polarization beam splitting element according to claim 1, wherein the optical element is formed in a toric shape. 6. The optical element is formed on the incident surface side of the optically isotropic substrate.
The polarized light separation element as described in any one of 5-5. 7. An incident surface side of the optically isotropic substrate surface,
7. The polarization beam splitting element according to claim 6, further comprising a regulation unit for regulating the distance between the laser beam source and the laser light source. 8. A restricting means for restricting a distance from a light receiving element that receives light diffracted by the diffraction grating is provided on the incident surface side of the optically isotropic substrate. The polarization separation element according to claim 6, which is characterized in that. 9. The polarization beam splitting element according to claim 8, wherein the light receiving element is brought into contact with the regulating means. 10. A laser light source that emits linearly polarized laser light, and an optical path formed between the laser light source and the laser light irradiation target, and formed into a film on an optically isotropic substrate. A polarization separation element having a polarizing diffraction grating formed on the surface of the optically anisotropic film, and a spread of laser light emitted from the laser light source, which is interposed between the laser light source and the polarization separation element. An optical element that changes the angle of the angle and emits laser light having a divergence angle after this change to the polarization separation element, and receives reflected light from the laser light irradiation target diffracted by the polarization separation element. A laser unit light source comprising a light receiving element. 11. A laser light source that emits linearly polarized laser light, and an optical path that is formed between the laser light source and a laser light irradiation target, provided in any one of claims 1 to 9. And a light receiving element for receiving the reflected light from the laser light irradiation target diffracted by the polarization separating element. 12. The laser unit light source according to claim 10, wherein the laser light source is composed of a plurality of laser light sources that oscillate lights having different oscillation wavelengths. 13. The laser unit light source according to claim 10, wherein the laser light source is composed of one laser light source capable of oscillating a plurality of lights having different oscillation wavelengths. 14. The laser unit light source according to claim 10, wherein the laser light source is a semiconductor laser light source.