WO2005112016A1

WO2005112016A1 - Composite optical element, optical integrated unit and optical pickup

Info

Publication number: WO2005112016A1
Application number: PCT/JP2005/008339
Authority: WO
Inventors: Masaru Ogawa
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2004-05-13
Filing date: 2005-05-06
Publication date: 2005-11-24
Also published as: JP2005327363A

Abstract

In a composite optical element (5), on a cross section (side cross section) in a direction connecting a semiconductor laser (1) with a monitor light receiving element (4), an opening width of an opening part (11) is different at a side cross section lower part (11a) and a side cross section upper part (11b). Thus the composite optical element (5) is constituted, a path of light entering an optical integrated unit (15) is not required to be limited more than necessary, while having desired light incident on the monitor light receiving element (4). A component and the like in the optical integrated unit (15) can be flexibly arranged.

Description

Specification

Composite optical element, optical integrated unit, and optical pickup device

Technical field

The present invention relates to a composite optical element, an optical integrated unit, and an optical pickup device, and more specifically, to a composite optical element for controlling light, an optical integrated unit, and an optical pickup device.

Background art

In recent years, research and development on technology for optically recording or reproducing information on an information recording medium such as an optical disk have been promoted. Hereinafter, conventional techniques described in JP-A-2001-110085, JP-A-2003-85807, and JP-A-2002-124727 (Patent Documents 1 to 3) will be described. In particular, JP-A-2001-110085 (Patent Document 1) will be described in detail with reference to FIG.

[0003] FIG. 11 is a schematic configuration diagram showing a schematic configuration of a conventional optical pickup device 100 used for an optical disk device or the like.

With reference to FIG. 11, a conventional optical pickup device 100 detects an information signal of an optical disk 103, and includes a hologram laser unit (optical integrated unit) 101 and an objective lens 102. The hologram laser unit 101 is a light receiving / emitting unit in which a semiconductor laser element 104 serving as a light source and a photodetector 105 that receives light reflected from the optical disk 103 are integrally formed. The semiconductor laser element 104 and the photodetector 105 are housed inside a sealing can (outer container) 106.

[0005] On the sealing can 106, a hologram element 108 is provided. Hologram element 108

A hologram pattern 109 is formed on the opposite surface of the plate glass from the semiconductor laser element 104 and the photodetector 105 side.

[0006] The laser beam 110 emitted from the semiconductor laser element 104 passes through the opening 1 of the sealing can 106.

07, the light passes through the hologram pattern 109 of the hologram element 108 in order, is incident on the objective lens 102, and is condensed at a predetermined position on the optical disc 103.

[0007] The reflected laser beam reflected by the optical disc 103 is reflected by the objective lens 102 at a predetermined position. Convergence is provided. The focused laser beam given the hologram element

The light is diffracted in a predetermined direction by the hologram pattern (diffraction pattern) 109 of the hologram element 108 and is incident on the photodetector 105 as a diffracted light beam 111.

[0008] A part of the laser beam 110 directed to the objective lens 102, for example, the laser beam reaching the objective lens 102 through the emission path 112 is reflected by the surface of the objective lens 102, and is reflected by the reflection path 113 to the hologram unit 101. To the photodetector 105. This reflected light is called stray light, and when it enters the photodetector 105, it becomes a factor of deteriorating the SZN (Signal to Noise) ratio of regular signal light.

In order to prevent this stray light (the laser beam reflected by the surface of the objective lens 102) from reaching the photodetector 105, the hologram unit 101 shown in FIG. Provide a mask 114!

[0010] The light-shielding mask 114 covers almost the entire area of the sealing can 106 and the hologram element 108, and has only an opening 115 large enough to allow the passage of the laser beam 110 from the semiconductor laser element 104 to the objective lens 102. Have. The light-shielding mask 114 reaches the surface of the objective lens 102 through the stray light emission path 112, and is reflected by the surface of the objective lens 102, and is other than the reflected laser beam incident on the photodetector 105 through the stray light reflection path 113. The reflected laser beam can be shielded from the reflected laser beam through the various optical paths.

An inner surface of the light-shielding mask 114 is coated with an anti-reflection film 114e that absorbs light having a wavelength of the laser beam 110. Accordingly, it is possible to prevent the generation of stray light that is reflected on the inner surface of the light shielding mask 114 and enters the light detector 105.

[0012] The conventional integrated unit described in Japanese Patent Application Laid-Open No. 2003-85807 (Patent Document 2) has a light emitting unit that emits a laser beam, and irradiates the disk with the laser beam to generate a reflected light from the disk. A hologram that is diffracted and guided to the light receiving section, and a light receiving section that receives the light diffracted by the hologram are provided, and the transmittance of a portion other than the hologram on the hologram element that transmits the reflected light from the disk is substantially reduced. It is characterized by being set to zero.

[0013] The conventional semiconductor laser unit described in Japanese Patent Application Laid-Open No. 2002-124727 (Patent Document 3) emits a laser beam having the power of a semiconductor laser through a hologram element and incident light to the hologram element. Is guided to the light receiving element and the semiconductor laser power is also emitted. A divergent light blocking means is provided for blocking divergent light of which intensity is smaller than the peak value of lZe ² among the light.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-110085

Patent Document 2: Japanese Patent Application Laid-Open No. 2003-85807

Patent Document 3: JP-A-2002-124727

Disclosure of the invention

Problems to be solved by the invention

In general, in an optical pickup device, when condensing light from a light source power on an optical disk via an objective lens or the like, it is necessary to perform a focus pull-in operation by swinging the objective lens in the optical axis direction. is there. In the focus pull-in operation, for example, the objective lens is moved from the near (far) side to the far (far) side of the optical disc by rocking, and the objective lens is held at a position where the focal point is located therebetween.

FIG. 12 is a diagram showing a curve of a general force error signal in the focus pull-in operation of the optical pickup device.

As shown in FIG. 12, when the objective lens enters the focus pull-in range FCR while moving from the near side to the far side, the objective lens is pulled into the focal point FP. In the focus pull-in operation, the swing range of the objective lens slightly varies depending on the optical disk system, but is generally required to be about ± 500 m from the focal point. Therefore, when the optical pickup device starts the focus pull-in operation, the objective lens is swung by about 500 μm in the optical axis direction by the actuator.

[0017] Such a swinging operation of the objective lens is one of the causes of causing stray light other than desired light to enter the photodetector. On the other hand, in Japanese Patent Application Laid-Open No. 2001-110085, by covering almost the entire area of the sealing can 106 and the hologram element 108 with the light shielding mask 114, only the desired reflected laser beam enters the sealing can 106. Like that.

However, in the optical pickup device 100 disclosed in Japanese Patent Application Laid-Open No. 2001-110085, in order to allow only a desired reflected laser beam to enter the sealing can 106, sealing is performed in all directions on a plane perpendicular to the optical axis direction. The path of the reflected laser beam incident on the stop 106 is restricted. Therefore, there is a problem that the arrangement of components and the like in the sealing can 106 is restricted. In Japanese Patent Application Laid-Open No. 2003-85807, the transmittance of a portion other than a hologram on a holo-drama element that allows reflected light from a disk to pass is made substantially zero, and in Japanese Patent Application Laid-Open No. 2002-124727, Of the laser light emitted from the laser, divergent light whose intensity is smaller than the peak value of lZe ² is blocked. However, also in these cases, the path of the reflected laser beam incident on the integrated laser unit (semiconductor laser unit) is limited in all directions on a plane perpendicular to the optical axis direction, and the components and the like in the integrated laser unit are not controlled. There were problems such as restrictions on placement.

[0020] Therefore, an object of the present invention is to provide a composite optical element, an optical integrated unit, and an optical pickup device in which a light path is not unnecessarily limited in a cross section different from a predetermined cross section in a light traveling direction. That is.

Means for solving the problem

The present invention is a composite optical element for controlling light, comprising a support plate having an opening through which light passes, wherein the opening has a cross section defined by a light traveling direction and a predetermined direction.

And a structure for preventing light from passing through the opening.

[0022] Preferably, in the cross section of the opening, one opening width and the other opening width of the opening are different from each other in a cross section defined by a light traveling direction and a predetermined direction.

[0023] Preferably, in the cross section defined by the light traveling direction and a predetermined direction, the width of one of the openings is smaller than the width of the other opening!

Preferably, in the opening, a straight line connecting one opening and the other opening of the opening is inclined with respect to the light traveling direction in a cross section defined by the light traveling direction and a predetermined direction. .

[0025] Preferably, the opening has a protrusion inside the end face of one of the openings in a cross section defined by a light traveling direction and a predetermined direction.

Preferably, one and the other of the openings in a cross section different from the cross section defined by the light traveling direction and the predetermined direction have an opening width in the cross section determined by the light traveling direction and the predetermined direction. It is larger than the opening width of one and the other of the part.

[0027] Preferably, the composite optical element is a composite optical element included in an optical integrated unit that outputs outgoing light to a recording medium and receives reflected light from the recording medium, wherein the optical integrated unit is

, A light source for outputting the emitted light, and a monitor light receiving element for receiving a part of the emitted light. A light emitting unit is provided, and the opening has a structure for preventing reflected light from entering the monitoring light receiving element in a cross section defined by a direction of the reflected light and a direction connecting the light source and the monitoring light receiving element.

[0028] Preferably, there is further provided a light condensing means provided between the optical integrated unit and the recording medium, for condensing the emitted light on the recording medium, and the opening is provided in a direction of the reflected light. And a direction connecting the light source and the monitoring light receiving element, a straight line connecting the opening on the light source side and the opening on the recording medium side is an angle along the numerical aperture on the light source side of the condensing unit. It is inclined.

[0029] Preferably, the apparatus further includes a first optical substrate fixed to the surface of the support plate on the light source side, and a second optical substrate fixed to the surface of the support plate on the recording medium side. The two optical substrates each have an optical element that changes the emitted light or the reflected light.

[0030] Preferably, the optical element is a polarization-separating optical element.

[0031] According to another aspect of the present invention, there is provided an optical integrated unit that outputs outgoing light to a recording medium and receives reflected light from the recording medium. A light receiving / emitting unit including a monitoring light receiving element for receiving the light, and a composite optical element including a support plate having an opening through which the emitted light and the reflected light of the recording medium force by the emitted light pass. The opening has a structure for preventing light from passing through the opening in a cross section defined by a light traveling direction and a predetermined direction.

[0032] Preferably, the opening has a structure for preventing the reflected light from entering the monitoring light receiving element in a cross section defined by the direction of the reflected light and the direction connecting the light source and the monitoring light receiving element.

[0033] Preferably, the light emitting / receiving unit further includes a rising mirror that transmits a part of the emitted light.

The monitor light receiving element receives light transmitted through the rising mirror.

[0034] Preferably, the light receiving / emitting unit further includes a light receiving element that detects reflected light.

According to still another aspect of the present invention, there is provided an optical pickup device for optically recording or reproducing information on or from a recording medium, comprising: a light source for outputting emitted light; A light receiving / emitting unit including a monitoring light receiving element, and a composite optical element having a support plate having an opening through which emitted light and reflected light of the emitted light from a recording medium pass. And an optical integrated unit including the optical integrated unit, and a condensing unit that condenses the emitted light on a recording medium. The opening has a structure for preventing light from passing through the opening in a cross section defined by a light traveling direction and a predetermined direction.

[0036] Preferably, the opening has a structure for preventing reflected light from entering the monitor light receiving element in a cross section defined by the direction of the reflected light and the direction connecting the light source and the monitor light receiving element.

According to the present invention, the light path is not unnecessarily limited in a cross section different from the predetermined cross section in the light traveling direction.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram showing a schematic configuration of an optical pickup device 200 as a background explaining an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a schematic configuration of another optical pickup device 300 as a background explaining an embodiment of the present invention.

FIG. 3 is a side sectional view showing a configuration of the optical pickup device 20 according to the embodiment of the present invention as viewed from a side section.

FIG. 4 is a plan sectional view showing a configuration of the optical pickup device 20 according to the embodiment of the present invention as viewed from a plan section.

FIG. 5 is a diagram showing a physical configuration of a composite optical element 55 according to an embodiment of the present invention.

FIG. 6 is a diagram showing a case where substantially parallel light is incident on the composite optical element 55 according to the embodiment of the present invention.

FIG. 7 is a diagram illustrating a case where divergent light is incident on the composite optical element 55 according to the embodiment of the present invention.

FIG. 8 is a diagram showing a physical configuration of a composite optical element 55A according to the embodiment of the present invention.

FIG. 9 is a diagram showing a state when the objective lens 8 is on the outer side in the optical pickup device 20 according to the embodiment of the present invention. FIG. 10 is a diagram showing a state when the objective lens 8 is on the far side in the optical pickup device 20 according to the embodiment of the present invention.

FIG. 11 is a schematic configuration diagram showing a schematic configuration of a conventional optical pickup device 100 used for an optical disk device or the like.

FIG. 12 is a diagram illustrating a curve of a general focus error signal in a focus pull-in operation of the optical pickup device.

Explanation of symbols

[0039] 1, 211 semiconductor laser, 2, 3, 52, 53 optical substrate, 4, 204 monitor light receiving element, 5, 55, 55A composite optical element, 7 collimating lens, 8, 102, 213 objective lens, 10 light Magnetic disk, 11, 51, 51A opening, 11a side cross section lower, lib side cross section upper, 11c flat cross section lower, lid flat cross section upper, 12, 50, 50A support plate, 14, 210 package, 15 optical integrated unit , 20, 100, 200 optical pickup device, 32, 34a, 34b polarization hologram, 35, 216 grating, 37a, 37b, 105, 215 photodetector, 40 start-up mirror one block, 40a, 206 start-up mirror, 41 Submount, 43 protrusion, 54 parts, 62, 63 optical element, 101 hologram laser unit, 103 optical disk, 104 semiconductor laser element, 106 sealing can, 205 reflecting part, 212 first polarization separation means, 214 2. Polarization separation means, 230 magneto-optical recording medium, 241 substrate.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.

Referring to FIG. 1, an optical pickup device 200 detects an information signal of a magneto-optical recording medium 230, and includes a knockout 210, an objective lens 213, and a base material 241. The package 210 includes a semiconductor laser 211, a first polarization separation unit 212, a second polarization separation unit 214 having a reflection unit 205, a photodetector 215, a grating 216, and a monitor light receiving element 204. This is an integrated optical unit.

[0043] The grating 216 controls the light emitted from the semiconductor laser 211 for tracking. Divide into three beams (not explicitly shown in Figure 1). The objective lens 213 focuses the light emitted from the semiconductor laser 211 on the recording surface of the magneto-optical recording medium 230. The base material 241 is made of, for example, glass and is arranged between the semiconductor laser 211 and the objective lens 213.

The first polarization separation means 212 is provided on the surface of the base material 241 on the side of the magneto-optical recording medium 230, and reflects reflected light from the magneto-optical recording medium 230 through the objective lens 213 to the magneto-optical recording medium 230. Separates in the radial direction (X direction). The second polarized light separating means 214 is provided on the surface of the substrate 241 on the side of the package 210, and further separates the reflected light separated by the first polarized light separating means 212. The photodetector 215 receives each beam (not explicitly shown in FIG. 1) separated by the second polarization separation means 214.

The first polarization separation means 212 is arranged as a means for having a function of increasing the Kerr rotation angle of the reflected light from the magneto-optical recording medium 230. The second polarization separation means 214 is used for differential operation of a magneto-optical signal, detection of a servo signal, and the like.

When recording information on the magneto-optical recording medium 230 using the optical pickup device 200, it is necessary to stably emit high output light from the semiconductor laser 211. The high output light is set to a predetermined output in a range of about 30 mW to 100 mW.

The light receiving element for monitoring 204 is arranged so that the optical path force of the light emitted from the semiconductor laser 211 to the magneto-optical recording medium 230 is deviated. The monitoring light-receiving element 204 detects light 240 of a portion of the light emitted from the front surface of the semiconductor laser 211 that does not reach the magneto-optical recording medium 230. The control circuit (not shown) feeds back the detected fluctuation of the optical output to keep the optical output emitted from the semiconductor laser 211 constant.

Referring to FIG. 2, optical pickup device 300 differs from optical pickup device 200 of FIG. 1 only in that package 210 is replaced with package 310. Therefore, description of overlapping parts will not be repeated here. The knockage 310 has a configuration in which a startup mirror 206 is added to the knockage 210. The rising mirror 206 is disposed between the semiconductor laser 211 and the monitoring light receiving element 204, and transmits a part of the light emitted from the semiconductor laser 211 in the X direction and guides the light to the monitoring light receiving element 204. . Here, with reference to FIG. 1, reflected light 217 from magneto-optical recording medium 230 via objective lens 213 shows a case where objective lens 213 is on the negative side (denoted by a dotted line). 2, the reflected light 218 from the magneto-optical recording medium 230 via the objective lens 213 indicates a case where the objective lens 213 is on the far side (denoted by a dotted line). Both of the reflected lights 217 and 218 pass through the base material 241 and enter the monitoring light receiving element 204.

As described above, there is a possibility that the monitoring light receiving element 204 shown in FIGS. 1 and 2 may detect light other than the light emitted from the front surface of the semiconductor laser 211 which should be originally detected. As a result, for example, the optical output monitor during the focus pull-in operation becomes unstable. As a result, there is a problem that the focus error signal level becomes unstable and an accurate focus pull-in operation becomes difficult. Hereinafter, a composite optical element, an optical integrated unit, and an optical pickup device that solve such a problem will be described in detail.

In the following embodiments, an optical pickup device for magneto-optical recording will be described as an example. However, the composite optical element, optical integrated unit, and optical pickup device according to the present invention are only used for magneto-optical recording. Not limited to

Referring to FIG. 3, an optical pickup device 20 according to an embodiment of the present invention detects an information signal of a magneto-optical disk 10, and forms an optical integrated unit 15, an objective lens 8, a collimating lens 7, Is provided.

The optical integrated unit 15 includes the composite optical element 5 and the node / cage 14. In the composite optical element 5, optical substrates 2 and 3 are fixed to the upper surface and the lower surface of the support plate 12, respectively. The support plate 12 has an opening 11 which is hollowed out at the center for light transmission. The composite optical element 5 is installed on the package 14 with the optical substrate 3 inserted in the package 14.

The package 14 includes at least the semiconductor laser 1, a submount 41, a start-up mirror block 40, and the monitoring light-receiving element 4 when viewed from a side cross section. The knockout 14 is a light receiving / emitting unit including the semiconductor laser 1 and the monitoring light receiving element 4. Here, the “side cross section” means a cross section in a direction connecting the semiconductor laser 1 and the monitoring light receiving element 4. As shown in FIG. 3, the composite optical element 5 viewed from the side cross section is configured such that the opening width (or opening diameter) force of the opening 11 is different between the lower side section 11a and the upper side section l ib. I have. Preferably, the opening 11 is formed to be inclined at an angle substantially along NA (Numerical Aperture) on the light source side of the collimating lens 7, for example. When the optical system of the optical pickup device is a finite system, that is, one objective lens, as in the optical pickup devices 200 and 300 shown in FIGS. 1 and 2, the NA on the light source side of the objective lens is approximately. It is also possible to configure the opening to be inclined at an angle along it.

The semiconductor laser 1 is mounted on a submount 41. The light (P-polarized light) emitted from the front surface of the semiconductor laser 1 travels to a start-up mirror 40a having a reflectance of about 90% and a transmittance of about 5%. The rising mirror 40a is formed by forming an optical film or the like on the 45-degree surface of the rising mirror block 40 that also has the strength of optical glass. The light reflected by the rising mirror 40a is incident on a grating 35 formed on the optical substrate 3 for generating a tracking beam.

On the other hand, the light transmitted through the rising mirror 40 a further passes through the rising mirror block 40 and enters the monitoring light receiving element 4. The monitoring light-receiving element 4 detects light emitted from the front surface of the semiconductor laser 1. The control circuit (not shown) keeps the light output emitted from the semiconductor laser 1 constant by feeding back the detected fluctuation of the output light amount.

The light passing through the grating 35 passes through the optical substrate 2 and the collimating lens 7, and is condensed on the recording surface of the magneto-optical disk 10 by the objective lens 8. The reflected light from the magneto-optical disk 10 has a slight S-polarized component because the plane of polarization rotates Kerr based on the recorded information according to the principle of the optical power effect. The reflected light from the magneto-optical disk 10 enters a polarization hologram 32 formed on the optical substrate 2.

The polarization hologram 32 has a 0-order diffraction efficiency of 77% for P-polarized light, 11% for ± 1st-order diffraction efficiency, and a 0% -order diffraction efficiency for S-polarized light and 44% for ± 1st-order diffraction efficiency. Is configured to. The polarization hologram 32 has a function of apparently multiplying the Kerr rotation angle of the reflected light from the magneto-optical disk 10.

FIG. 4 is a plan sectional view showing a configuration of the optical pickup device 20 according to the embodiment of the present invention as viewed from a plan section. In the optical pickup device 20 shown in FIG. 4, the appearance of the optical integrated unit 14 is different because the side sectional view has been changed to the plan sectional view. In the following, differences from FIG. 3 will be mainly described. Here, the “planar section” means a section perpendicular to the “side section” in FIG.

The package 14 includes at least the semiconductor laser 1, a submount 41, a start-up mirror 40a, and photodetectors 37a and 37b when viewed from a plan section. Here, the “planar section” means a section perpendicular to the direction connecting the semiconductor laser 1 and the monitor light-receiving element 4.

As shown in FIG. 4, in the composite optical element 5 viewed from a plane cross section, the diffraction lights 32 a and 32 b by the polarization hologram 32 are generated in the X direction. Therefore, the width of the lower section 11c and the upper section lid of the opening 11 is formed larger than the width of the lower section 11a and the upper section lib of FIG.

[0066] Preferably, the width of the lower side section 11a and the upper side section ib of the opening 11 is formed slightly larger than the diameter of the light beam passing therethrough in consideration of tolerance. In addition, the width of the lower section 11c and the upper section lid of the flat section are configured to be the same, for example, in consideration of the addition point and the like. In this case, the opening 11 of the support plate 12 in the plane cross section is formed parallel to the optical axis direction.

When the reflected light from the magneto-optical disk 10 passes through the polarization hologram 32, a phase difference of about several tens degrees may occur between the P-polarized light and the S-polarized light of the reflected light. In this case, by arranging the phase difference plates 39b and 39a for giving an appropriate phase difference, it is possible to correct the phase difference generated in the + 1st-order diffracted light 32b and the -first-order diffracted light 32a.

[0068] The + first-order diffracted light 32b and the first-order diffracted light 32a respectively enter the polarization holograms 34b and 34a formed on the optical substrate 3 and are separated in predetermined directions. Is detected. Here, the polarization hologram 34b is a light separating means for detecting a magneto-optical signal and a servo signal, and the polarizing hologram 34a is a light separating means for detecting a magneto-optical signal.

As described above with reference to FIGS. 3 and 4, the composite optical element 5 of the optical pickup device 20 according to the embodiment of the present invention has a cross section in the direction connecting the semiconductor laser 1 and the monitoring light receiving element 4. In the (side section), the opening width of the opening 11 is the lower side section 11a and the upper side section l ib. Are configured differently. On the other hand, in a cross section (planar cross section) perpendicular to the direction connecting the semiconductor laser 1 and the monitor light receiving element 4, the composite optical element 5 has a flat cross section lower portion 11c and a flat cross section upper lid of the opening 11 having a width. It is formed larger than the width of the lower side section 11a and the upper side section lib of FIG.

By configuring the composite optical element 5 in this way, it is possible to make the desired light incident on the monitoring light receiving element 4 and to unnecessarily restrict the path of the light incident on the optical integrated unit 15. Thereby, components and the like in the optical integrated unit 15 can be flexibly arranged.

Hereinafter, a specific configuration of the composite optical element 5 viewed from a side cross section will be described in detail with reference to FIGS. The composite optical element 5 is a versatile element, and can be used for various purposes other than the optical pickup device 20 shown in FIGS. Therefore, the following FIGS. 5 to 8 will be described using reference numerals different from those in FIGS.

FIG. 5 is a diagram showing a physical configuration of the composite optical element 55 according to the embodiment of the present invention.

Referring to FIG. 5, in composite optical element 55 according to the embodiment of the present invention, optical substrates 52 and 53 are aligned with one surface 56b and the other surface 56a of support plate 50, respectively. Fixed. The support plate 50 has an opening 51 at the center, and light can pass through the opening 51 in one direction or two directions. The composite optical element 55 is arranged, for example, at the portion of the base material 241 in FIGS.

[0074] On optical substrates 52 and 53, optical elements 62 and 63 that perform control such as separation, division, diffraction, polarization, stop, filtering, and phase control of light passing through opening 51 of support plate 50 are provided. Each is formed. Examples of the optical elements 62 and 63 include a hologram element, a diffraction grating, a liquid crystal element, and an optical crystal. The support plate 50 and the optical substrates 52 and 53 are integrated to form a composite optical element 55 as a whole.

As shown in FIG. 5, the width of the lower side section 51a of the opening 51 is smaller than the width of the upper side section 51b. The width of the lower side section 51a and the upper side section 51b of the opening 51 is preferably formed slightly larger than the diameter of the light beam passing therethrough in consideration of tolerance. When the converging light 57A is incident from the upper part of the composite optical element 55, since the aperture 51 is narrowed as shown in FIG. Light 57A is restricted as shown in FIG.

[0076] By configuring the composite optical element 55 as described above, it is possible to prevent the light 58A from directly entering the component 54 installed below the composite optical element 55. Examples of the component 54 include a sensor such as a photodetector, and a component that, when exposed to light, causes a temperature rise or the like to cause a malfunction. The support plate 50 needs to be made of an opaque material so that the direct light 58A does not pass through the support plate 50.

FIG. 6 is a diagram illustrating a case where substantially parallel light is incident on the composite optical element 55 according to the embodiment of the present invention.

As shown in FIG. 6, even when the parallel light 57B is incident on the composite optical element 55, the parallel light 57B that passes through the opening 51 and exits to the optical substrate 53 side does not It is restricted as follows. Therefore, even in the case of parallel light, it is possible to prevent the light 58B from directly entering the component 54 installed below the composite optical element 55.

FIG. 7 is a diagram showing a case where divergent light is incident on composite optical element 55 according to the embodiment of the present invention.

As shown in FIG. 7, even when the divergent light 57C is incident on the composite optical element 55, the divergent light 57C that passes through the opening 51 and is emitted toward the optical substrate 53 is the same as in FIG. It is restricted as follows. Therefore, even in the case of divergent light, it is possible to prevent the light 58C from directly entering the component 54 installed below the composite optical element 55.

Referring to FIG. 8, in composite optical element 55A, the shape of opening 51A is different from that of openings 51 in FIGS. Specifically, the opening 51A is formed in parallel with the optical axis direction, and the projections 43 are provided on both side surfaces of the lower side section 51a. Even with such a configuration, it is possible to prevent light from directly entering the component 54 installed below the composite optical element 55A.

Next, an operation of the optical pickup device 20 according to the embodiment of the present invention as viewed from a side cross section will be described with reference to FIGS. Note that the scale of FIGS. 9 and 10 is arbitrary for convenience of description, and the composite optical element 5 and the optical integrated The scale is not based on the dimensions of the knit 15, the objective lens 8, the collimating lens 7, etc. The scale is not based on the relative dimensions of the objective lens 8, the collimating lens 7, etc. taking into account the focal length.

FIG. 9 is a diagram showing a state (dashed line) when the objective lens 8 is on the negative side in the optical pickup device 20 according to the embodiment of the present invention. The optical path shown by the solid line indicates a state where the objective lens 8 is at the focal point.

Referring to FIG. 9, objective lens 8 indicated by a broken line is in a state where it is rocked by about 500 m in a direction approaching magneto-optical disk 10 (your side) by an actuator (not shown). Indicates that it is located. Here, the certain state refers to a state in which the beam diameter of the reflected light from the magneto-optical disk 10 expands inside the package 14 (than the beam diameter at the time of focusing) at the time of focusing pulling to the near side.

[0086] As shown in Fig. 9, when the objective lens is on the negative side, the reflected light 21 from the magneto-optical disk 10 generally enters the package 14 along the opening 11 of the support plate 12 and is monitored. Does not directly enter the light receiving element 4 for use. Thereby, even during the focus pull-in operation, the light output emitted from the front surface of the semiconductor laser 1 can be kept constant. As a result, the level of the focus error signal is stabilized, and an accurate focus pull-in operation can be performed.

FIG. 10 is a diagram showing a state (broken line) when the objective lens 8 is on the S-far side in the optical pickup device 20 according to the embodiment of the present invention. The optical path shown by the solid line indicates a state where the objective lens 8 is at the focal point.

Referring to FIG. 10, objective lens 8 indicated by a broken line is swung by an actuator (not shown) by about 500 m in a direction (far side) away from magneto-optical disk 10. Indicates that the vehicle is in a certain state for a while. Here, the certain state refers to a state in which the beam diameter of the reflected light from the magneto-optical disk 10 expands inside the package 14 (than the beam diameter at the time of focusing) at the time of focusing on the fur side.

As shown in FIG. 10, when the objective lens is on the far side, the reflected light 22 from the magneto-optical disk 10 is once collected at the upper Za from the emission point of the semiconductor laser 1. After that, the reflected light 22 from the magneto-optical disk 10 enters the optical integrated unit 15 with a narrow beam diameter. The beam diameter diverges inside the knock 14.

Here, the reflected light 22 a from the magneto-optical disk 10 that enters the inside of the knock 14 is limited by the width of the lower part 11 a of the support plate 12 in the side section of the opening 11. The width of the lower portion 11a of the side section is configured so that the reflected light 22 does not directly enter the monitor light receiving element 4. Therefore, even during the focus pull-in operation, the reflected light 22a from the magneto-optical disk 10 does not enter the motor light receiving element. As a result, the optical output emitted from the semiconductor laser 1 can be kept constant. As a result, the level of the focus error signal is stabilized, and an accurate focus pull-in operation becomes possible.

The shape of the opening 11 of the support plate 12 is not limited to the shape shown in FIGS. 9 and 10. For example, as shown in FIG. 8, a projection 43 is provided below the opening 51. May be adopted.

As described above, the composite optical element according to the embodiment of the present invention has, in a cross section in the direction connecting the light source and the monitoring light receiving element, an opening having a structure in which reflected light does not enter the monitoring light receiving element. . This makes it possible to prevent the light that has entered the one-way force and exited through the opening from directly entering another component arranged. By using the composite optical element in an optical integrated unit or the like constituting an optical pickup device, it is possible to prevent reflected light of the optical recording medium from being directly incident on a light receiving element for monitoring an optical output of a semiconductor laser. it can.

[0093] Further, the optical integrated unit according to the embodiment of the present invention is used in combination with the light condensing means for condensing light on the optical recording medium, so that the reflected light of the optical recording medium can be monitored even during the focus pull-in operation. Light can be prevented from directly entering the light receiving element for use. As a result, since the level of the focus error signal is stabilized, an accurate focus pull-in operation can be performed by using the focus error signal together with a light focusing means for focusing the light on the optical recording medium.

[0094] Further, the optical pickup device according to the embodiment of the present invention can prevent the reflected light of the optical recording medium from directly entering the monitor light receiving element even during the focus pull-in operation. As a result, the level of the focus error signal is stabilized, so that an accurate focus pull-in operation can be performed.

[0095] The embodiments disclosed this time are examples in all respects and are not restrictive. Should be considered. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Claims

The scope of the claims

[1] A composite optical element (5, 55, 55A) for controlling light,

A support plate (12, 50, 50A) having an opening (11, 51, 51A) through which the light passes, wherein the opening (11, 51, 51A) is provided in a direction in which the light travels and in a predetermined direction. A composite optical element having a structure for preventing the light from passing through the openings (11, 51, 51A) in a determined cross section.

[2] The opening (51) is characterized in that one opening width and the other opening width of the opening (51) are different from each other in a cross section defined by a traveling direction of the light and a predetermined direction. The composite optical element described in paragraph 1.

[3] The opening (51) is characterized in that, in a cross section defined by a traveling direction of the light and a predetermined direction, one opening width of the opening (51) is smaller than the other opening width. The composite optical element described in section 2.

[4] The opening (51) has a cross section defined by a traveling direction of the light and a predetermined direction, and a straight line connecting one opening and the other opening of the opening (51) is formed by a light traveling direction. 3. The composite optical element according to claim 2, wherein the composite optical element is inclined with respect to a direction.

[5] The opening (51A) has a projection (43) inside from an end face of one opening of the opening (51A) in a cross section defined by a traveling direction of the light and a predetermined direction. 2. The composite optical element according to item 1, wherein

[6] The opening in a cross section different from a cross section determined by a traveling direction of the light and a predetermined direction

The width of one of the openings (11) and the width of the other of the openings (11) are larger than the width of one of the openings (11) and the other of the openings (11) in a cross section defined by the traveling direction of the light and a predetermined direction. 2. The composite optical element according to item 1.

[7] The composite optical element (5) is a composite optical element included in the optical integrated unit (15) that outputs emitted light to the recording medium (10) and receives reflected light of the recording medium (10). (5) The optical integrated unit (15) is a light receiving / emitting unit including a light source (1) for outputting the emitted light and a monitoring light receiving element (4) for receiving a part of the emitted light. (14), the opening (11), the direction of the reflected light, the light source (1) and the monitor light receiving element ( 2. The composite optical element according to claim 1, wherein the composite optical element has a structure that prevents the reflected light from being incident on the monitor light receiving element (4) in a cross section determined by a direction connecting the light receiving element and the light receiving element.

[8] Light-collecting means (7, 8) provided between the optical integrated unit (15) and the recording medium (10), for condensing the emitted light on the recording medium (10) is further provided. ,

The opening (11) has a section defined by a direction of the reflected light and a direction connecting the light source (1) and the light receiving element for monitoring (4), and has an opening on the light source (1) side. 8. The method according to claim 7, wherein a straight line connecting to the opening on the recording medium (10) side is inclined at an angle along the numerical aperture on the light source (1) side of the condensing means (7). Composite optical element.

[9] A first optical substrate (3) fixed to the surface of the support plate (12) on the light source (1) side, and fixed to a surface of the support plate (12) on the recording medium (10) side. And a second optical substrate (2),

The claim 7, wherein the first and second optical substrates (2, 3) respectively have optical elements (32, 34a, 34b, 35) that change the outgoing light or the reflected light. 3. The composite optical element according to item 1.

[10] The optical device according to claim 1, wherein the optical element (32, 34a, 34b) is a polarization-separating optical element.

Item 10. The composite optical element according to item 9.

[11] An optical integrated unit (15) which outputs emitted light to a recording medium (10) and receives reflected light of the recording medium (10),

A light receiving / emitting unit (14) including a light source (1) for outputting the emitted light, and a monitoring light receiving element (4) for receiving a part of the emitted light;

A composite optical element (5, 55, 55A) including a support plate (12, 50, 50A) having openings (11, 51, 51A) through which the emitted light and reflected light from the recording medium by the emitted light pass. ) And

The opening (11, 51, 51A) has a structure for preventing the light from passing through the opening (11, 51, 51A) in a cross section defined by a traveling direction of the light and a predetermined direction. Optical integrated unit.

[12] The light emitting / receiving unit (14)

Further comprising a rising mirror (40) that transmits a part of the emitted light, The optical integrated unit according to claim 11, wherein the monitor light receiving element (4) receives light transmitted through the rising mirror (40).

13. The optical integrated unit according to claim 11, wherein said light emitting / receiving unit (14) further includes a light receiving element (37a, 37b) for detecting said reflected light.

[14] An optical pickup device (2) for optically recording or reproducing information on a recording medium (10)

0)

A light receiving / emitting unit (14) including a light source (1) for outputting the emitted light and a monitoring light receiving element (4) for receiving a part of the emitted light; and the recording by the emitted light and the emitted light. An optical integrated unit (15) including a composite optical element (5, 55, 55A) including a support plate (12, 50, 50A) having an opening (11, 51, 51A) through which reflected light passes. When,

Light-collecting means (7, 8) for condensing the emitted light on the recording medium (10), wherein the openings (11, 51, 51A) are determined by a traveling direction of the light and a predetermined direction. An optical pickup device, having a structure in a cross section, for preventing the light from passing through the openings (11, 51, 51A).