JP4041713B2 - Optical pickup device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an optical pickup device including a plurality of laser light emission light sources.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, there are optical pickup devices for recording and reproducing optical discs that support two types of optical discs. This type of optical pickup apparatus needs to use laser beams having different wavelengths depending on the type of optical disk. For example, when both recording and reproduction of a CD and a DVD are performed, a first laser device that emits laser light for writing and reading data to and from the CD to the optical pickup device, and writing of data to the DVD And a second laser device that emits laser light for reading.
[0003]
  FIG. 21 is a sectional view of the conventional optical pickup device. This optical pickup device includes a first light source 211 that emits a first laser beam having a wavelength λ1 for data reproduction, a second light source 212 that emits a second laser beam having a wavelength λ2 for data reproduction and data recording, A light separation element 213, a second light source light monitor 215, and an objective lens 214 are provided.
[0004]
  The light separating element 213 is bonded to one side surface of the first triangular prism 216 on the first light source 211 side and one side surface of the second triangular prism 217 on the second light source 212 side via a wavelength selection film 218. Is formed by.
[0005]
  The wavelength selection film 218 of the conventional optical pickup device transmits only a few percent of the first laser light having the wavelength λ1 emitted from the first light source 211, and the first wavelength λ1 emitted from the first light source 211. While almost reflecting one laser beam, only a few percent of the second laser beam having the wavelength λ2 emitted from the second light source 212 is reflected, and the second laser beam having the wavelength λ2 emitted from the second light source 212 is reflected. It is almost transparent. Then, several percent of the second laser beam reflected by the wavelength selection film 218 is incident on the second light source light monitor 215 to control the light output of the second light source.
[0006]
  In the above configuration, when reading the data written on the data reading optical disk 210 using the first laser light having the wavelength λ1 emitted from the first light source 211, the laser light emitted from the first light source 211 is converted into the wavelength. After being reflected toward the objective lens 214 by the selection film 218, the light is condensed at one point on the optical disk 210 by the objective lens 214. Then, data (for example, pid information) of the optical disk 210 is extracted from the first laser light reflected at one point on the optical disk 210 and again transmitted through the objective lens 214 using a hologram element, a light receiving element, or the like (not shown). The optical pickup device controls the light output of the first light source 211 by changing the amount of laser light emitted from the first light source 211 in the same package as the first light source 211. It is detected by an optical monitor (not shown).
[0007]
  On the other hand, the second laser beam having the wavelength λ2 emitted from the second light source 212 is used to write on the data reading optical disk 210 (even if different optical disks are used, the same reference numeral 210 is assigned to the optical disk). When reading out the read data, the second laser light emitted from the second light source 2 is transmitted through the wavelength selection film 218 and then focused on a point on the optical disk 210 by the objective lens 214. Then, data written on the optical disk is taken out from the second laser light reflected at one point on the optical disk 210 and again passed through the objective lens 214 using a hologram element, a light receiving element or the like (not shown).
[0008]
  In addition, when data is written to the data writing optical disk 210 using the second laser light having the wavelength λ 2 emitted from the second light source 212, the second laser light emitted from the second light source 212 is used as the wavelength selection film 218. Then, the light is focused on one point on the optical disk 210 by the objective lens 214 to write data on the optical disk 210. In this optical pickup device, in order to control the light output of the second light source 212, the amount of the second laser light emitted from the second light source 212 and reflected by the wavelength selection film 218 is changed to the second light source. It is detected by the light monitor 215 for use.
[0009]
  Optical signals detected by the first light source light monitor and the second light source light monitor 215 are converted into electric signals, respectively, and these electric signals are provided on the optical pickup device or outside the optical pickup device (not shown). Input to an automatic power control (APC) circuit. Then, the respective outputs of the automatic output control circuits corresponding to the optical signals of the first light source light monitor and the second light source light monitor 215 are fed back to the first and second light sources 211 and 212, and the first light source 211 and 212 are fed back. The optical output of the second light sources 211 and 212 is controlled.
[0010]
[Patent Document 1]
          JP 11-328708 A
[0011]
[Problems to be solved by the invention]
  However, in the conventional optical pickup device described above, in order to control the light output of the second light source 212, a few percent of the second laser light emitted from the second light source 212 is reflected by the wavelength selection film 218 and used for the second light source. Since the light enters the optical monitor 215, there is a problem in that the amount of light transmitted through the wavelength selection film 218 and irradiated onto the optical disc 210 by the objective lens 214 is reduced by the amount of laser light reflected by the wavelength selection film 218. is there. That is, by reducing the amount of the second laser beam emitted from the second light source 212 and entering the optical disc 210, the data reproduction capability (or the optical disc 210 using the second laser beam emitted from the second light source 212) (or There is a problem in that the ability to record data on the optical disk 210 decreases.
[0012]
  Further, in order to avoid this problem, even if the reflectance of the laser light emitted from the second light source 212 with respect to the wavelength selection film 218 is designed to be as small as possible, for example, as small as about 5%, as shown below. There is a problem. That is, in the current mass production technology, the reflectance of the wavelength selection film 218 has a variation of about ± 4%. For example, the reflectance of the second laser light emitted from the second light source 212 to the wavelength selection film 218 is 5 When setting to%, the reflectance of the laser light with respect to the wavelength selection film 218 varies in the range of 1% to 9%. As a result, the dynamic range (ratio between the minimum value and the maximum value) of the light amount of the second laser light emitted from the second light source 212 and reflected by the wavelength selection film 218 and incident on the second light source light monitor 215 is 9. There is a problem that the output light quantity of the second light source 212 cannot be accurately detected due to the large variation of about twice.
[0013]
  Further, when the reflectance varies in the direction of decreasing, the amount of laser light incident on the second light source light monitor 215 decreases, and the S / N ratio (signal / noise) in the optical signal of the second light source light monitor 215 is reduced. Ratio) decreases, and it is difficult to detect the output light amount of the second light source 212.
[0014]
  Further, when the wavelength λ2 of the second laser light of the second light source 212 changes due to a temperature change or the like, the reflectance of the wavelength λ2 of the second laser light by the wavelength selection film 218 changes, and the light monitor 215 for the second light source. In general, if the reflectance is set to be low as described above, the variation of the reflectance due to the change in wavelength increases. Therefore, the amount of light of the second light source 212 is changed to the second light source light monitor 215. There is a problem that it cannot be detected accurately.
[0015]
  Further, in the conventional optical pickup device, a part of the second laser light incident on the wavelength selection film is reflected toward the second light source monitor, and therefore the wavelength formed on one triangular prism constituting the light separation element. In some cases, a method of forming a reflective film that reflects a part of the second laser light on the selective film is used. In this case, in the vapor deposition step of forming the reflective film on the wavelength selective film, Problems such as applying a film stress to the selective film and altering the wavelength selective film, or damaging the underlying wavelength selective film due to heat and work handling during the deposition of the reflective film occur. There is a problem that the production efficiency of the separation element is lowered.
[0016]
  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical pickup device that is excellent in data reproduction capability and data recording capability of an optical disc and has high production efficiency that can accurately detect the output light amount of a laser light source.
[0017]
[Means for Solving the Problems]
  In order to achieve the above object, an optical pickup device of the present invention comprises:
  A first light source that emits a first laser beam;
  A second light source that emits a second laser beam having a wavelength different from that of the first laser beam;
  An objective lens for condensing the first and second laser beams on the data recording surface of the optical disc;
  An optical monitor for detecting the amount of the second laser beam;
  A wavelength selection film that reflects the first laser light emitted from the first light source toward the objective lens and transmits the second laser light emitted from the second light source to be incident on the objective lens; A light separating element that is formed so as not to come into contact with the wavelength selection film and has reflecting means for reflecting the second laser light emitted from the second light source toward the optical monitor;
With,
  The first prism with the wavelength selection film sandwiched between at least a part of one side of the first prism on the first light source side and at least a part of one side of the second prism on the second light source side Bonding at least part of one side surface and at least part of one side surface of the second prism on the second light source side,
  The reflecting means is disposed on the second prism;
  The reflecting means is a non-contact surface provided on a part of the one side of the second prism so as not to contact the one side of the first prism.It is characterized by that.
[0018]
  In this specification, the expression “formed so as not to come into contact with this wavelength selection film” means that the wavelength selection film and the reflection means are formed as separate members and the wavelength selection film is formed on the reflection member. When the light separation element is formed by pasting together the member on which the means is formed, the wavelength selective film and the reflecting means are in contact with each other when the member on which the wavelength selective film is formed and the member on which the reflecting means are formed. Including the case of doing.
[0019]
  In the above configuration, when reading the data written on the data recording surface of the optical disc (for data reading) using the first laser light emitted from the first light source, the laser light emitted from the first light source is After being reflected by the wavelength selection film toward the objective lens, it is condensed on the data recording surface of the optical disk by the objective lens. Then, data (for example, pid information) of the optical disk is extracted from the laser light reflected on the data recording surface of the optical disk and again passed through the objective lens by using optical means such as a hologram element and a light receiving element.
[0020]
  In addition, when data is written on the optical disc (for data writing) using the first laser beam emitted from the first light source, the laser beam emitted from the first light source is reflected toward the objective lens by the wavelength selection film. After that, data is written onto the optical disk by focusing on the data recording surface of the optical disk with the objective lens.
[0021]
  Note that the amount of light emitted from the first light source when writing data to the data writing optical disk is larger than the amount of light emitted from the first light source when reading data from the normal data reading optical disk, and controls the amount of light emitted from the first light source. There is a need. For this reason, after detecting the emitted light quantity of the 1st light source with the light monitor for 1st light sources provided in the package of the 1st light source, for example, this emitted light quantity is converted into an electric signal, and this electric signal is converted. Input is made to an automatic output control circuit provided on or outside the optical pickup device. The output from the automatic output control circuit is fed back to the first light source to control the light output of the first light source.
[0022]
  On the other hand, when reading the data written on the optical disk (for data reading) using the second laser beam emitted from the second light source, the laser beam emitted from the second light source is transmitted through the wavelength selection film. Thereafter, the light is condensed on the data recording surface of the optical disk by the objective lens. Then, data written on the data recording surface of the optical disk is extracted from the light reflected by the data recording surface on the optical disk and again passed through the objective lens by using optical means such as a hologram element and a light receiving element.
[0023]
  In addition, when data is written to the optical disc (for data writing) using the second laser light emitted from the second light source, the second laser light emitted from the second light source is transmitted through the wavelength selection film. Then, data is written onto the optical disc by focusing on the data recording surface on the optical disc with the objective lens.
[0024]
  As with the first light source, in the second light source as well, the amount of light emitted from the second light source when writing data to the data writing optical disk is greater than the amount of light emitted from the second light source when reading data from the normal data reading optical disk. It is necessary to control the amount of light emitted from the second light source. For this reason, the second laser light emitted from the second light source and incident on the reflecting means is reflected by the reflecting means toward the optical monitor, and the amount of the second laser light incident on the optical monitor is detected. Thereafter, the light quantity of the second laser light incident on the optical monitor is converted into an electric signal, and this electric signal is input to the automatic output control circuit. The output from the automatic output control circuit is fed back to the second light source to control the light output of the second light source.
[0025]
  According to the optical pickup device of the present invention, the wavelength selection film and the reflection means are arranged so as not to contact each other. Therefore, by appropriately adjusting the positions of the wavelength selection film and the reflection means, All of the second laser light incident on the selection film can be transmitted toward the objective lens. Therefore, unlike the conventional optical pickup device, it is not necessary to reflect the second laser beam by several% with the wavelength selection film, so that the amount of the second laser beam condensed on the data recording surface of the optical disk via the objective lens is increased. Thus, the data reproducing ability and data recording ability of the optical disc can be improved.
[0026]
  Further, since the light separation element is formed so that the wavelength selection film and the reflection means do not come into contact with each other, the wavelength selection film and the reflection means can be formed in separate steps. Therefore, the problem that occurs in the conventional optical pickup device in which after forming the wavelength selection film on one side of the triangular prism, the reflection film as the reflection means is formed on the wavelength selection film, that is, the reflection film as the reflection means. The problem of changing the wavelength selective film by applying a film stress to the underlying wavelength selective film in the vapor deposition process of forming a film, or damage to the underlying wavelength selective film due to heat or work handling during the deposition of the reflective film Problems can be avoided, the manufacturing yield of the light separating element can be improved, and the manufacturing cost of the light separating element can be reduced.
[0027]
[0028]
  In this specification, the prism is formed in a substantially prismatic shape made of a transparent substance such as glass, acrylic, quartz, resin material, synthetic quartz, or BK-7 (at least one of the side surfaces of the prism may be a curved surface). ), And the triangular prism is defined as a prism that is a triangle having a cross-section in a direction perpendicular to the column direction of the prism. Further, in this specification, a right-angle prism is defined as a prism that is a right-angle triangle having a substantially constant cross section in a direction perpendicular to the column direction of the prism. In addition, when the term “side surface” is used in this specification, this side surface means a surface extending in the column direction of the prism.
[0029]
  The present inventionAccording to this optical pickup device, before bonding at least a part of one side of the first prism on the first light source side and at least a part of one side of the second prism on the second light source side, The wavelength selection film may be disposed on the first prism, and the reflection unit may be disposed on the second prism, which is a separate member from the first prism. Therefore, the step of forming the wavelength selection film on the first prism and the step of forming the reflecting means on the second prism can be performed at the same time, and the productivity of the light separation element can be increased. In addition, since the member that forms the wavelength selection film and the member that forms the reflecting means are separate members, the manufacturing yield of the light separating element can be further improved, and the manufacturing cost of the light separating element can be further reduced.
[0030]
[0031]
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[0044]
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[0048]
[0049]
[0050]
[0051]
[0052]
[0053]
[0054]
[0055]
[0056]
[0057]
[0058]
[0059]
  The present inventionAccording to this optical pickup device, the reflecting means is a non-contact surface provided on a part of the one side of the second prism so as not to contact the one side of the first prism. The second laser light emitted from the two light sources,UpBy adjusting the position of the non-contact surface so that it is reflected by the non-contact surface and enters the optical monitor, the reflecting means can be formed easily and inexpensively. Therefore, the cost of the light separating element can be reduced and the mass productivity of the light separating element can be increased.
[0060]
  In the optical pickup device according to an embodiment, the second prism is a triangular prism, and the second prism in which the corner of the triangular prism on the non-contact surface side is incident on the objective lens. The non-contact surface is formed on the second prism by forming a shape cut substantially parallel to the optical axis of the laser beam.
[0061]
  According to the optical pickup device of the above embodiment, the first prism is cut so that the corner of the triangular prism on the non-contact surface side is substantially parallel to the optical axis of the second laser light incident on the objective lens. Since the shape is made, the areas of the first and second laser light emitting surfaces of the first prism from which the first and second laser lights are emitted in the light separating element can be increased. Therefore, since the first and second laser beams can be prevented from being scattered by the first and second laser beam emission surfaces, the first and second laser beams can be reliably incident on the objective lens, and the optical disc The data reproduction ability and data recording ability can be improved. In addition, since the area of the non-contact surface that is the reflection means can be increased, the amount of the second laser light incident on the optical monitor can be increased.
[0062]
  In one embodiment, the first and second prisms are triangular prisms.
[0063]
  According to the optical pickup device of the above embodiment, since the first and second prisms are triangular prisms, the non-contact surface can be formed without cutting the triangular prism. That is, the non-contact surface as the reflecting means can be easily and inexpensively formed by using a method such as appropriately shifting and bonding two identical side surfaces of two triangular prisms having the same shape. Therefore, the manufacturing cost of the light separating element can be further reduced.
[0064]
  In one embodiment, the optical pickup device includes the first prism as a triangular prism, and the second prism is connected to the first prism connected to the bonding surface with the first prism via a step portion. It has a non-contact surface.
[0065]
  According to the optical pickup device of the above embodiment, the first prism is a triangular prism, and the second prism is connected to the first prism connected to the bonding surface with the first prism via a step portion. Since the non-contact surface is provided, the non-contact surface is appropriately processed to adjust the incident angle of the second laser light to the non-contact surface, thereby arranging the optical monitor at the optical pickup location. It can be easily adjusted to a place convenient for downsizing the device.
[0066]
  In one embodiment of the present invention, the second prism is formed of a triangular prism, and the first prism is connected to the second prism connected to the bonding surface with the second prism via a step portion. It has a non-contact surface.
[0067]
  According to the optical pickup device of the above embodiment, the first prism has a surface that is non-contact with the second prism connected to the bonding surface with the second prism via the step portion. The edge part on the second light source side does not scatter the second laser light. Therefore, generation | occurrence | production of the unnecessary stray light in an optical pick-up apparatus can be suppressed.
[0068]
  In one embodiment, the optical pickup device includes the first prism as a first triangular prism, the second prism as a second triangular prism, and at least one side surface of the first triangular prism. And a part of one side surface of the second triangular prism are bonded to each other through an adhesive layer.
[0069]
  According to the optical pickup device of the above embodiment, since at least a part of one side of the first triangular prism and a part of one side of the second triangular prism are bonded via the adhesive layer, the reflecting means It is not necessary to cut the triangular prism to form the non-contact surface of a certain second triangular prism. Therefore, the light separating element can be manufactured easily and inexpensively.
[0070]
[0071]
[0072]
[0073]
[0074]
[0075]
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[0090]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0091]
  (FirstReference example)
  FIG. 1 shows the firstReference exampleIt is sectional drawing of the optical pick-up apparatus. FirstReference exampleThe optical pickup apparatus includes a first light source 1 that emits a first laser beam having a wavelength λ1, a second light source 2 that emits a second laser beam having a wavelength λ2, a light separation element 3, an objective lens 4, and a first lens. An optical monitor 5 for two light sources and an automatic output control (APC) circuit (not shown) are provided.
[0092]
  A light source monitor (not shown) for measuring the light amount of the first light source 1 is provided in the package of the first light source 1.
[0093]
  The light separating element 3 is formed of a triangular prism 6 on the first light source 1 side made of glass and a triangular prism 7 on the side of the second light source 2 made of glass. Specifically, the light separating element 3 is formed by bonding one side surface of the triangular prism 6 on the first light source 1 side and one side surface of the second triangular prism 7 on the second light source side with an adhesive. Yes.
[0094]
  A wavelength selection film 8 is formed on substantially the entire surface of the one side of the triangular prism 6. The wavelength selection film 8 reflects the first laser beam having the wavelength λ1 emitted from the first light source 1 to the objective lens 4 by approximately 100% and the second laser having the wavelength λ2 emitted from the second light source 2. It is designed to allow light to pass through approximately 100% and enter the objective lens 4.
[0095]
  On the other hand, a reflective film 9 as an example of a reflecting means is formed on a part of one side of the triangular prism 7 on the objective lens 4 side. The reflection film 9 is designed to reflect the second laser light emitted from the second light source 2 and incident on the reflection film 9 toward the second light source light monitor 5. The reflective film 9 is a metal-deposited reflective film obtained by depositing a metal such as Al which has a high reflectance even when the wavelength of the incident second laser light fluctuates due to a temperature change or the like. On the surface, or a mirror having a dielectric-deposited reflective film deposited with a dielectric on the surface.
[0096]
  FIG. 2 is an enlarged view of the vicinity of the bonding surface of the triangular prism 6 and the triangular prism 7 in the light separating element 3.
[0097]
  As shown in FIG. 2, the wavelength selection film 8 and the reflection film 9 are bonded to each other with an adhesive 14 therebetween, and the wavelength selection film 8 and the reflection film 9 are not in direct contact with each other. It has become. The reflective film 9 is disposed at a location where it does not come into contact with the first and second laser beams incident on the objective lens 4 via the wavelength selection film 8.
[0098]
  In the above-described configuration, the optical disk for data reading 10 (using the first laser light having the wavelength λ1 emitted from the first light source 1 (Reference examples andIn the description of the embodiment of the present invention, when reading data written on the optical disk, the optical disk is designated by reference numeral 10 regardless of the optical disk, the wavelength of the first laser beam emitted from the first light source 1 is selected. After being reflected by the film 8 toward the objective lens 4, the film is condensed on a point on the optical disk 10 by the objective lens 4. Then, data (for example, pid information) of the optical disk 10 is extracted from the first laser light reflected at one point on the optical disk 10 and again passed through the objective lens 4 by using a hologram element, a light receiving element, or the like (not shown).
[0099]
  Further, when data is written to the data writing optical disk 10 using the first laser light having the wavelength λ 1 emitted from the first light source 1, the first laser light emitted from the first light source 1 is used as the wavelength selection film 8. After the light is reflected substantially toward the objective lens 4, the data is written on the optical disk 10 by being focused on a point on the optical disk 10 by the objective lens 4.
[0100]
  The amount of light emitted from the first light source 1 when data is written to the data writing optical disk 10 is usually larger than the amount of light emitted from the first light source 1 when data is read from the data reading optical disk 10. It is necessary to control the amount of emitted light. For this reason, the amount of light emitted from the first light source 1 is detected by the first light source optical monitor, and then converted into an electrical signal, which is provided on the optical pickup device or outside the optical pickup device (not shown). Input to the automatic output control circuit. The output from the automatic output control circuit is fed back to the first light source 1 to control the light output of the first light source 1.
[0101]
  On the other hand, when reading the data written on the data reading optical disk 10 using the second laser light having the wavelength λ2 emitted from the second light source 2, the second laser light emitted from the second light source 2 is converted into the wavelength. After passing through the selection film 8, the light is condensed on one point on the optical disk 10 by the objective lens 4. Then, data written on the optical disk 10 is extracted from the second laser light reflected at one point on the optical disk 10 and again passed through the objective lens 4 by using a hologram element, a light receiving element or the like (not shown).
[0102]
  Further, when data is written to the data writing optical disk 10 using the second laser light having the wavelength λ2 emitted from the second light source 2, the second laser light emitted from the second light source 2 is used as the wavelength selection film 8. Then, the light is focused on one point on the optical disk 10 by the objective lens 4 to write data on the optical disk 10.
[0103]
  In the second light source 2 as well as the first light source 1, the amount of light emitted from the second light source 2 when writing data on the data writing optical disk 10 is the second light source when reading data from the data reading optical disk 10. The amount of emitted light from the second light source 2 needs to be controlled, which is usually larger than the amount of emitted light of 2. For this reason, the second laser light emitted from the second light source 2 and incident on the reflection film 9 is reflected by the reflection film 9 toward the second light source light monitor 5 and incident on the second light source light monitor 5. The amount of the second laser beam is detected. Thereafter, the amount of the second laser light incident on the second light source light monitor 5 is converted into an electric signal, and this electric signal is input to the automatic output control circuit. The output from the automatic output control circuit is fed back to the second light source 2 to control the light output of the second light source 2.
[0104]
  The firstReference exampleAccording to this optical pickup apparatus, since the reflective film 9 is disposed at a place where it does not come into contact with the first and second laser lights incident on the objective lens 4 via the wavelength selection film 8, the second All of the second laser light emitted from the light source 2 and incident on the wavelength selection film 8 can be transmitted to the objective lens 4. Therefore, unlike the conventional optical pickup device, it is not necessary to reflect the second laser beam by several% with the wavelength selection film, so that the amount of the second laser beam condensed on the data recording surface of the optical disk 10 by the objective lens 4 is increased. Thus, the data reproduction capability and data recording capability of the optical disc 10 can be improved.
[0105]
  Further, before the light separating element 3 is formed by bonding one side surface of the triangular prism 6 and one side surface of the triangular prism 7, the wavelength selection film 8 is provided on the triangular prism 6 in advance and the reflection film 9 is formed on the triangular prism 7. Therefore, the wavelength selection film 8 and the reflection film 9 can be formed in separate steps. Therefore, after the wavelength selective film is formed on one side of the triangular prism, the problem that occurs in the conventional method of forming the reflective film on the wavelength selective film, that is, the wavelength selection of the base in the vapor deposition process for forming the reflective film. The problem of changing the wavelength-selective film by applying film stress to the film, or the problem of damaging the underlying wavelength-selective film due to heat or work handling during the deposition of the reflective film can be avoided, and the manufacturing yield of the prism can be reduced. The manufacturing cost of the light separating element 3 can be reduced.
[0106]
  Further, since the optical characteristics such as reflectance and transmittance of the wavelength selection film 8 depend on the refractive index of the film composition of the wavelength selection film 8 and the refractive index of the member in contact with the film, the wavelength selection film 8 and the reflection film 9 The optical properties of the wavelength selective film 8 are independent of the reflective film 9 (depending on the reflective film 9) by interposing the adhesive 14 between the wavelength selective film 8 and the reflective film 9 without directly contacting Without setting). Accordingly, the position and material of the reflective film 9 that reflects the second laser light of the second light source 2 to the second light source monitor 5 has a degree of freedom of selection. As a result, the second light source light monitor 5 is selected. Therefore, the optical pickup apparatus can be made compact by effectively using these selection degrees of freedom.
[0107]
  Further, since the wavelength selection film 8 has a reflectance of approximately 100% with respect to the first laser light, the first laser light emitted from the first light source 1 enters the triangular prism 6 and then enters the triangular prism 6. The arranged wavelength selective film 8 reflects almost 100%. Accordingly, since the first laser light emitted from the first light source 1 does not reach the reflection film 9 disposed on the side surface of the triangular prism 7 where the triangular prism 6 is bonded, the first laser light is reflected by the reflection film. 9 is not affected, and a further degree of freedom is generated in the formation position and material of the reflective film 9.
[0108]
  Further, even if the wavelength of the incident second laser light fluctuates due to a temperature change or the like, the reflectance is not easily affected, and a metal-deposited reflective film on which a metal such as Al having high reflectance is deposited is provided on the surface. Since the reflection film 9 is composed of a mirror or a mirror having a dielectric-deposited reflection film having a dielectric deposited thereon, the wavelength of the second laser light emitted from the second light source 2 changes due to a temperature change or the like. However, the reflectance of the reflective film 9 is not affected. Therefore, the light quantity of the second light source 2 can be accurately detected by the second light source light monitor 5.
[0109]
  The firstReference exampleIn the optical pickup apparatus, the light separating element 3 is formed by bonding one side surface of the triangular prism 6 on the first light source 1 side and one side surface of the triangular prism 7 on the second light source 2 side. Of course, one of the prisms having another shape such as a pentaprism may be substituted.
[0110]
  (SecondReference example)
  FIG. 3 shows the secondReference exampleIt is sectional drawing of the optical pick-up apparatus. SecondReference exampleThe optical pickup device of the firstReference exampleReflecting means (first portion) disposed on the side surface of the triangular prism 7 of the optical pickup device to which the triangular prism 6 is bonded.Reference exampleThen, the area of the reflective film 9) is increased in the direction approaching the first light source 1, and the second light source 2 is arranged in the direction perpendicular to the data recording surface of the optical disc (not shown). The first point is the point close to the first point and the point where the reflection means is not formed of the reflection film but the reflection type diffraction grating 19 is used.Reference exampleDifferent from the optical pickup device.
[0111]
  SecondReference exampleIn the first optical pickup device, the firstReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0112]
  This secondReference exampleIn the optical pickup apparatus, since the second light source 2 is moved closer to the light separation element 3 in the direction perpendicular to the data recording surface of the optical disc, the second light source 2 is emitted from the first light source 1 and reflected by the wavelength selection film 8. The beam diameter 25 of the first laser light in the projection of the incident portion of the wavelength selection film 8 of the first laser light incident on the objective lens 4 onto the optical disc is emitted from the second light source 2 and transmitted through the wavelength selection film 8 to be objective. It becomes larger than the beam diameter 24 of the second laser light in the projection of the incident portion of the wavelength selection film 8 of the second laser light incident on the lens 4 onto the optical disc.
[0113]
  Second aboveReference exampleAccording to this optical pickup apparatus, the second light source 2 is moved closer to the light separation element 23 in the direction perpendicular to the data recording surface of the optical disc, and the light beam diameter 24 is set smaller than the light beam diameter 25. Therefore, the size of the reflective diffraction grating 19 can be set large. Accordingly, since the amount of the second laser light emitted from the second light source 2 and incident on the second light source light monitor 5 can be increased, the S / N of the signal output from the second light source light monitor 5 can be increased. The ratio can be improved, and the emission output of the second light source 2 can be accurately detected.
[0114]
  Further, since the reflecting means is constituted by the reflective diffraction grating 19, the reflection angle of the second laser light can be easily adjusted by changing the grating pitch. Therefore, a degree of freedom of selection is generated in the arrangement of optical components from the second light source 2 to the second light source light monitor 5, and the optical pickup device can be made compact.
[0115]
  The secondReference exampleIn this optical pickup device, glass is used as the material of the light separating element 23, but a resin material may be used as the material of the light separating element. In this case, a reflective diffraction grating is formed on the mold of the light separating element. Reflecting means can be formed easily and inexpensively just by keeping it. Therefore, the firstReference exampleCompared with the case where the reflecting means is formed by using a vapor deposition film as in the optical pickup apparatus, mass productivity is improved and the cost of the optical pickup apparatus can be reduced.
[0116]
  The firstReference exampleSince the first laser beam from the first light source 1 is totally reflected by the wavelength selection film 8 as in the optical pickup apparatus of FIG. 1, even if the reflection type diffraction grating 19 is located at the position where it overlaps the portion of the beam diameter 25, the first laser beam is reflected. The laser beam does not reach the reflective diffraction grating 19. Therefore, the reflection type diffraction grating 19 is disposed within the light beam diameter 25 as long as it does not reflect the second laser light emitted from the second light source 2 and reaching the objective lens 4 (not shown in FIG. 3). It does not matter.
[0117]
  (ThirdReference example)
  FIG. 4 shows the thirdReference exampleIt is sectional drawing of the optical pick-up apparatus. ThirdReference exampleIn this optical pickup device, the point where the triangular prism 17 on the second light source 2 side is small and the area of the reflective diffraction grating 29 disposed on the side surface of the triangular prism 17 where the triangular prism 6 is bonded are close to those of the first light source 1. The second point is that the second light source 2 is further closer to the light separating element 33 in the direction perpendicular to the data recording surface of the optical disk (not shown).Reference exampleDifferent from the optical pickup device.
[0118]
  ThirdReference exampleIn the second optical pickup device, the secondReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0119]
  The light separation element 33 is provided in a divergent light beam emitted from the first light source 1 and the second light source 2.
[0120]
  In the above-described configuration, the first laser light emitted from the first light source 1 is reflected by the wavelength selection film 8 incident on the triangular prism 6 of the light separating element 33 and reflected by about 100%, and then the objective lens 4 from the triangular prism 6. To the side. That is, the first laser light from the first light source 1 travels through the light separating element 33 by a distance corresponding to the size of the triangular prism 6.
[0121]
  On the other hand, the second laser light emitted from the second light source 2 enters the triangular prism 17 having a small size of the light separating element 33, passes through the wavelength selection film 8 of the light separating element 33, and is objective from the triangular prism 6. The light is emitted to the lens 4 side. That is, the second laser light from the second light source 2 travels through the light separating element 33 by a distance corresponding to the size of the triangular prism 6 and the triangular prism 17.
[0122]
  Third aboveReference exampleAccording to the optical pickup apparatus, since the triangular prism 17 facing the second light source 2 is made small, the secondReference exampleThe second light source 2 of the optical pickup device of FIG.Reference exampleThe second light source 2 can be further moved to the objective lens 4 side from the distance moved to the objective lens 4 side with respect to the second light source 2 of the optical pickup apparatus. Therefore, the light condensing point 41 by the objective lens 4 of the second laser light emitted from the second light source 2 is more optically split than the light condensing point 42 by the objective lens 4 of the first laser light emitted from the first light source 1. It can be located on the side far from the element 33. Therefore, the thirdReference exampleThere are differences in the thickness of the substrates of the two types of optical disks (hereinafter referred to as the first optical disk and the second optical disk) used in the optical pickup apparatus, and the distance between the objective lens 4 and the first optical disk (referred to as the first distance). ) And the distance between the objective lens 4 and the second optical disk (referred to as a second distance), the distance between the condensing points 41 and 42 is changed to the first distance and the second distance. By adjusting to the difference, it is possible to cope with the difference in the thickness of the substrate of the optical disk. Accordingly, since it is not necessary to deal with the difference in the positions of the condensing points 41 and 42 by a method of increasing the operation range of the objective lens, the optical pickup device can be configured in a compact manner.
[0123]
  The thirdReference exampleWhen the optical disc used in the optical pickup apparatus is a CD and a DVD, the thickness of the optical disc substrate is 1.2 mm and 0.6 mm, respectively, and the distance between the objective lens 4 and the optical disc is about 0.4 mm. There is a difference. In such a case, the second light source 2 is emitted from the second light source 2 by moving the second light source 2 toward the objective lens 4 while using the first light source 1 for DVD and the second light source 2 for CD. The condensing point 41 of the laser light by the objective lens 4 is positioned farther from the light spectroscopic element 33 than the condensing point 42 of the first laser light emitted from the first light source 1 by the objective lens 4. In this way, the distance difference of 0.4 mm between the objective lens 4 and the optical disk is adjusted.
[0124]
  In addition, the thirdReference exampleAccording to this optical pickup device, the triangular prism 17 on the second light source 2 side is made small so that the installation position of the second light source is the second.Reference exampleSince the optical pickup device is moved further to the light separation element 33 side than the installation position of the second light source 2 of the second optical pickup device, the secondReference exampleCompared with the optical pickup apparatus of FIG. 1, the optical disc (not shown) of the incident portion in the wavelength selection film 8 of the first laser light emitted from the first light source 1 and reflected by the wavelength selection film 8 and incident on the objective lens 4 is used. ) And the light beam diameter of the first laser light in the projection to the optical disk of the incident portion of the wavelength selection film 8 of the second laser light emitted from the second light source 2 and transmitted through the wavelength selection film 8 and incident on the objective lens 4 The difference from the light beam diameter of the second laser light in the projection can be further increased, and the reflection type diffraction grating 29 can be set larger. Therefore, the amount of the second laser light emitted from the second light source 2 and incident on the second light source light monitor 5 can be further increased to improve the S / N ratio of the output signal of the second light source light monitor 5. Therefore, the amount of light emitted from the second light source 2 can be detected more accurately.
[0125]
  Further, since the distance from the second light source 2 to the objective lens 4 is shortened, the optical pickup device can be made compact.
[0126]
  (4thReference example)
  FIG. 5 shows the fourthReference exampleIt is sectional drawing of the optical pick-up apparatus. The firstReference exampleTo thirdReference exampleIn this optical pickup device, the reflecting means is provided on the side far from the second light source 2 on the bonding surface of the triangular prism on the second light source side with the triangular prism on the first light source side.Reference exampleIn the optical pickup apparatus, the reflecting means is provided on the side closer to the second light source 2 of the bonding surface of the triangular prism 57 on the second light source side with the triangular prism 6 on the first light source side. This fourthReference exampleIn this optical pickup device, the reflection means is intentionally provided on the side closer to the second light source 2, thereby causing problems when the reflection means is provided on the side closer to the second light source 2, and the reflection means. The advantages of providing it on the side far from the second light source will be described.
[0127]
  4thReference exampleIn the optical pickup device of the thirdReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0128]
  The reflecting means is the firstReference exampleThe reflective film 59 is the same material as the reflective film 9 used in FIG. The reflective film 59 is provided on the side close to the second light source 2, and the second laser light emitted from the second light source 2 is guided to the second light source light monitor 5.
[0129]
  However, in this case, the position of the second laser light emitted from the second light source 2 and incident on the reflective film 59 is close to the second light source 2, and the incident angle θ of the second laser light on the reflective film 59 is the first. 1Reference exampleTo thirdReference exampleTherefore, the second light source optical sensor 5 must be provided at a position close to the second light source 2. This means that when a semiconductor laser is normally used as the second light source 2, a package 55 made of a metal of the semiconductor laser covering the periphery of the semiconductor laser for heat dissipation and environmental resistance is used for the second light source. This means that it is close to the optical monitor 5, which means that it is difficult to reduce the size of the optical pickup device.
[0130]
  Further, as shown in FIG. 5, the position where the second laser light emitted from the second light source 2 and reflected by the reflective film 59 is emitted from the triangular prism 57 on the second light source 2 side is near the apex angle of the triangular prism 57. It is also not preferable to become. Because the thirdReference exampleWhen the triangular prism on the second light source side is made smaller as in the optical pickup apparatus of FIG. 5, the second laser light is scattered near the apex angle of the triangular prism on the second light source side and enters the optical sensor 5 for the second light source. This is because the amount of the second laser light is reduced.
[0131]
  In order to avoid such a problem, the reflecting means is provided on the side of the bonding surface of the triangular prism on the second light source side with the triangular prism on the first light source side that is far from the second light source, and the second light source and the second light source. The optical pickup device is miniaturized by increasing the distance of the light monitor for the light source.
[0132]
  In FIG. 5, reference numeral 63 denotes an optical disc at an incident portion of the wavelength selection film 8 of the second laser light emitted from the second light source 2 and transmitted through the wavelength selection film 8 and incident on the objective lens (not shown). The beam diameter of the second laser beam in the projection (not shown) is shown. Reference numeral 64 is the first laser beam emitted from the first light source 1 and reflected by the wavelength selection film 8 and incident on the objective lens. The beam diameter of the first laser beam in the projection of the incident portion of the wavelength selective film 8 onto the optical disc is shown.
[0133]
  (5thReference example)
  FIG. 6 shows the fifthReference exampleIt is sectional drawing of the optical pick-up apparatus. 5thReference exampleThe optical pickup apparatus 1 includes a hologram element 68 having a hologram pattern 68 a disposed between the second light source 2 and the light separation element 3, and first and second reflections from the optical disk 61 and diffracted by the hologram element 68. Only the point provided with the photodetector 69 for receiving the laser beam is the first.Reference exampleDifferent from the optical pickup device.
[0134]
  5thReference exampleIn the first optical pickup device, the firstReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0135]
  In the above configuration, the 0th-order light 63 of the second laser light that is emitted from the second light source 2 and enters the hologram element 68 and is not diffracted by the hologram pattern 68a forms a spot on the surface of the optical disk 10 by the objective lens 4. To do. Then, the zero-order light 63 reflected by this spot passes through the objective lens 4 and the light separation element 3 again, and then enters the hologram pattern 68a. Then, the first-order diffracted light at the hologram pattern 68a in the 0th-order light incident on the hologram pattern 68a is photoelectrically converted by the photodetector 69, and data reproduction on the optical disc 10 is performed.
[0136]
  On the other hand, the diffracted light 64 emitted from the second light source 2 and incident on the hologram pattern element 68 and diffracted by the hologram pattern 18a is reflected by the reflective film 9 of the light separating element 6 and is reflected by the second light source light monitor 5. Is incident on.
[0137]
  Above 5Reference exampleAccording to this optical pickup apparatus, diffracted light emitted from the second light source and diffracted by the hologram element pattern 68a is used as the second laser light incident on the reflection film 9 in order to detect the amount of light emitted from the second light source 2. Therefore, of the second laser light emitted from the second light source 2, the laser light near the center having higher intensity can be reflected by the reflection film 9 and guided to the second light source light monitor 5. Accordingly, the S / N ratio of the signal output from the second light source light monitor 5 can be improved, and the amount of light emitted from the second light source 2 can be accurately detected.
[0138]
  In addition, since the hologram element 68 is provided after the reflection film 9 is provided on the portion of the wavelength separation film 8 of the light separation element 3 that faces away from the second light source 2, the diffracted light diffracted by the hologram pattern 18a is provided. The degree of separation from the zero-order light that is not diffracted by the hologram pattern 18a increases. Therefore, the reflection film 9 is provided on the portion of the light separation element 3 facing the far side from the light source 2 of the wavelength selection film 8, and the hologram element 68 is provided between the second light source 2 and the light separation element 3. Due to this synergistic effect, a larger amount of the second laser light can be guided to the second light source light monitor 5.
[0139]
  (No. 6Reference example)
  FIG. 7 shows the sixthReference exampleIt is sectional drawing of the optical pick-up apparatus. 6thReference exampleIn this optical pickup device, the normal line between the optical axis 72 of the zero-order light emitted from a second light source (not shown) and traveling straight without being diffracted by the hologram pattern 68a, and the wavelength selection film 8 of the light separation element is The angle formed is θa, and is diffracted by the hologram pattern 68a emitted from the second light source and finally incident on the light monitor 5 for the second light source. When the diffraction angle is θh,
            2θa + θh ≒ 90 ° (1)
Only the point where the conditionReference exampleDifferent from the optical pickup device.
[0140]
  6thReference exampleIn the optical pickup device of the fifth,Reference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0141]
  6thReference exampleIn the optical pickup apparatus, the second laser light reflected by the reflective film as the reflecting means and incident on the second light source light monitor 5 and the 0th order light emitted from the second light source and not diffracted by the hologram pattern 68a are generated. When the formed angle is α, the relationship shown in Expression (2) is established for the angles α, θa, and θh.
[0142]
            α = 180 ° -2θa-θh (2)
Therefore, the sixthReference exampleIn the optical pickup apparatus, the relationship of the following equation (3) is established from the relationship of the equation (1) and the relationship of the equation (2).
[0143]
            α ≒ 90 ° (3)
  6th aboveReference exampleAccording to the optical pickup apparatus, the second laser light reflected by the reflective film (not shown) and incident on the second light source light monitor 5 and the 0th order emitted from the second light source and not diffracted by the hologram pattern 68a. Since the angle α formed with the light is set to approximately 90 °, it is easy to make the second laser light incident perpendicularly to the light receiving surface of the second light source light monitor 5. Therefore, since the incident light quantity of the second laser light per unit area of the light receiving surface can be maximized, the S / N ratio of the signal output from the second light source light monitor 5 is improved, and the second The amount of light emitted from the light source 2 can be accurately detected.
[0144]
  Further, since the second light source light monitor 5 is installed in parallel to the optical axis of the 0th-order light (the central axis of the 0th-order light beam) 72, the degree of freedom in arrangement of components in the optical pickup device is increased. Therefore, it is possible to reduce the size of the optical pickup device.
[0145]
  The sixthReference exampleIn the optical pickup apparatus, θa and θh are set so as to satisfy Expression (1). However, after θa and θh are set so as to satisfy Expression (1), the following is further set between θa and θh. The conditions of the expressions (4) and (5) shown may be applied, and in this case, the optical pickup device can be made of high quality.
[0146]
            30 ° ≦ θa ≦ 37 ° (4)
            11 ° ≦ θh ≦ 35 ° (5)
  That is, by making the condition of equation (5) to θh, it is better to make the angle larger from the viewpoint of avoiding that the diffracted light is irradiated onto the optical disk and becoming unnecessary stray light, while the hologram pattern needs to be miniaturized. From the standpoint of mass productivity, it is possible to balance the value of θh, which is better when the angle is small. Further, by applying the condition of Equation (4) to θa, the condition that θa that improves the wavefront of the light of the first light source reflected by the wavelength selection film 8 is close to 0 ° (vertical incident angle), It is also possible to balance the conditions of 1) and formula (4). Therefore, it is possible to reduce the size of the optical pickup device.
[0147]
  (No. 7Reference example)
  FIG. 8 shows the seventhReference exampleIt is a fragmentary sectional view of the optical pick-up apparatus. 7thReference exampleThis optical pickup device essentially changes the shape of the triangular prism 86 on the side of the first light source (not shown) and the triangular prism 87 on the side of the second light source (not shown) that constitute the light separating element 83. Thus, the point that the light separating element 83 is replaced is the sixth point.Reference exampleDifferent from the optical pickup device.
[0148]
  Specifically, the seventhReference exampleThe triangular prism 87 on the hologram pattern 68a side of the optical pickup apparatus of FIG. 5A has a vertex θt of 90 ° on the second light source light monitor 5 side and the hologram pattern 68a side, and the other two angles are θa and (90 ° −θa) at right angles. This is a prism 87 (hereinafter, a right-angle prism is also given a reference number 87). Further, the triangular prism 86 has a side surface having an area equivalent to the area of the side surface facing the apex angle θt which is a right angle in the right-angle prism 87. The side surface of the triangular prism 86 is bonded to the side surface facing the apex angle θt of the right-angle prism 87 without a gap, thereby forming the light separation element 83.
[0149]
  7thReference exampleIn the optical pickup device of the sixth,Reference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0150]
  The first side face of the triangular prism 86 is bonded to the right-angle prism 87.Reference exampleA wavelength selection film 88 made of the same material as that of the wavelength selection film 8 is formed, and a first portion of the wavelength selection film 88 of the light separation element is opposed to the side far from the second light source 2.Reference exampleA reflective film 89 made of the same material as the reflective film 9 is provided.
[0151]
  In addition, the sixthReference exampleIn the same manner as the optical pickup apparatus, the optical axis 81 of the zero-order light that is emitted from the second light source (not shown) and goes straight without being diffracted by the hologram pattern 68a, and the wavelength selection of the light separation element (not shown) The angle θa formed by the normal line of the film 88 and the hologram pattern 68a in the second laser light emitted from the second light source 2 and diffracted by the hologram pattern 68a and finally incident on the second light source light monitor 5 Between the diffraction angles θh of the first-order diffracted light 82, the condition of formula (1) (2θa + θh≈90 °) is satisfied.
[0152]
  The side surface 87a of the right light prism 87 on the second light source light monitor side 5 is formed of a ground glass surface as an example of a light scattering surface. The ground glass-like side surface 87a serves to scatter a small amount of the second laser light that is reflected by the reflective film 89 and does not transmit through the side surface 87a. The side surface 87a on the second light source light monitor 5 side is provided with an antireflection film (AR coating) for suppressing the reflection of the second laser light on the side surface 87a.
[0153]
  Above 7Reference exampleAccording to this optical pickup device, the triangular prism on the hologram pattern 68a side is made into a right-angle prism 87 that is easy to process and suitable for mass production, so that the cost can be reduced.
[0154]
  Further, since the triangular prism on the hologram pattern 68a side is a right-angle prism 87, the direction of the second laser light emitted from the second light source (not shown), diffracted by the hologram pattern 68a, and reflected by the reflecting film 89 is changed. The normal direction of the side surface 87a of the right-angle prism 87 on the second light source light monitor side can be matched. Therefore, since the second laser light is not refracted by the side surface 87a, it is not necessary to consider the displacement of the position of the second laser light due to refraction with respect to the arrangement of the second light source light monitor 5, and the optical pickup device The design can be simplified.
[0155]
  In addition, since the side surface 87a on the second light source light monitor side is formed as a ground glass surface that has been subjected to antireflection film processing as an example of a light scattering surface, after reflection by the reflection film 89, the antireflection film processing is performed. A small amount of the second laser light that does not pass through the applied side surface 87a can be scattered and emitted. Therefore, normally, even when an antireflection film (AR coating) is provided, the second laser light reflected by the side surface 87a with a reflectivity of about 0.5 to 1% is optically transmitted in a substantially reverse direction on the path incident on the side surface 87a. It is possible to prevent the phenomenon of unnecessary stray light returning to the system, to prevent the recording / reproducing characteristics of the optical disk from deteriorating, and to stabilize the operation of the optical pickup device. The seventhReference exampleIn the optical pickup apparatus, since the condition of Expression (1) is satisfied and the prism on the side surface 87a side is the right-angle prism 87, the second laser light is incident on the side surface 87a substantially perpendicularly.
[0156]
  Further, since the side surface 87a of the right-angle prism 87 is formed as a ground glass surface, the right-angle prism 87 can be manufactured at low cost and the mass productivity of the right-angle prism 87 can be further enhanced.
[0157]
  The seventhReference exampleIn this optical pickup device, in order to suppress the second laser light reflected by the side surface 87a from becoming stray light, the side surface 87a on the second light source light monitor side is formed of a ground glass-like material with an antireflection film processed. However, the side surface on the second light source light monitor 5 side may be the cut surface in the step of cutting out the right-angle prism from the glass substrate. Further, it is not necessary to provide an antireflection film depending on the degree of the scattering effect.
[0158]
  (EighthReference example)
  FIG. 9 shows the eighthReference exampleIt is sectional drawing of the optical pick-up apparatus. 8thReference exampleIn this optical pickup device, the corner of the triangular prism on the first light source (not shown) side facing the portion where the reflective film 9 was provided is cut off, and the surface of the triangular prism 97 on the second light source 2 side is cut. Only the point that a part is exposed and this exposed surface is made a reflecting surface 99 as an example of the reflecting means is essentially the first.Reference example(Other differences include, for example, the fact that the area of the wavelength selection film is small).
[0159]
  8thReference exampleIn the first optical pickup device, the firstReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0160]
  8th aboveReference exampleIn this optical pickup device, the incident angle of the second laser beam that is emitted from the second light source 2 and reflected by the reflecting surface 99 and incident on the light receiving surface of the second light source light monitor 5 is ψ. When the refractive index of the triangular prism 97 on the second light source 2 side is n, the following formula (6) is established in which the reflection surface 99 is a total reflection surface.
[0161]
            n × sinψ ≧ 1 (6)
  8th aboveReference exampleAccording to this optical pickup apparatus, the reflecting means of the prism 96 on the first light source side can be formed by simply cutting one corner of the triangular prism, and has a metal-deposited reflective film on which metal such as Al is deposited on the surface. Since there is no need to provide a reflecting means having a complicated structure such as a mirror, a mirror having a dielectric-deposited reflective film deposited with a dielectric, or a reflective diffraction grating on the surface, the triangular prism on the second light source side has excellent mass productivity. The light separating element 93 can be manufactured easily and inexpensively.
[0162]
  Further, since the condition of the formula (6) is met, the reflectance can be theoretically made 100%. Therefore, as compared with the case where a vapor deposition reflective film or a reflective diffraction grating is used, a larger amount of light is led to the second light source light monitor 5, and the S / N ratio of the output signal of the second light source light monitor 5 is calculated. Can be improved.
[0163]
  (No. 9Reference example)
  FIG. 10 shows the ninthReference exampleIt is sectional drawing of the light separation element with which the optical pick-up apparatus of FIG. 9thReference exampleIn the optical pickup apparatus, the corner of the triangular light source 106 on the second light source optical sensor (not shown) side of the triangular prism 106 on the first light source (not shown) side is cut.Reference exampleThe cut surface 101 is substantially parallel to the optical axis 102 of the second laser beam emitted from the second light source (not shown) and incident on the objective lens (not shown). Here, the state in which the cut surface 101 and the optical axis 102 do not intersect is called parallel).Reference exampleDifferent from the optical pickup device.
[0164]
  9th aboveReference exampleIn the optical pickup apparatus, since the cut surface 101 is parallel to the optical axis 102, the first and second laser beams on the objective lens (not shown) side from which the first and second laser beams are emitted from the prism 106 are emitted. The area of the emission surface 106b can be increased. Therefore, since the first laser light scattered by the first and second laser light emission surfaces 106b can be suppressed, the first and second laser lights can be reliably incident on the objective lens, and an optical disk (not shown). The data reproduction ability and data recording ability can be improved.
[0165]
  Further, since the cut surface 101 is parallel to the optical axis 102, the area of the reflection surface 109 as an example of the reflection means can be increased, and the second light source incident on a second light source light monitor (not shown). 2 The amount of laser light can be increased.
[0166]
  (10thReference example)
  FIG. 11 shows the tenthReference exampleIt is sectional drawing of the light separation element with which the optical pick-up apparatus of FIG. The triangular prism 116 is connected to the second light source so that there is no step between the triangular prisms 116 on the two equivalent first light source (not shown) sides and 117 on the second light source (not shown) side. The light separating element 113 is formed by laminating to the side. A wavelength selection film 118 is formed on the entire side surface of the triangular prism 116 having a bonded portion with the triangular prism 117 on the second light source side (not shown). Further, a non-contact portion between the triangular prism 117 and the triangular prism 116 on the side of the objective lens (not shown) on the side surface having the bonded portion with the triangular prism 116 and the second light source photosensor side (not shown) is The reflecting surface 119 is an example of the reflecting means.
[0167]
  10th aboveReference exampleAccording to the optical pickup device, the eighth and ninthReference exampleSince it is not necessary to cut the triangular prism on the first or second light source side as in the optical pickup apparatus, the cost can be reduced.
[0168]
  (No.1Embodiment)
  FIG.1It is sectional drawing of the light separation element with which the optical pick-up apparatus of embodiment is provided. The light separation element 123 includes a part of one side surface of the triangular prism 126 arranged on the first light source (not shown) side, and one side surface of the prism 127 arranged on the second light source (not shown) side. Are formed by bonding.
[0169]
  The prism 127 has a shape such that an end of one side surface of the triangular prism is cut. The prism 127 has a step portion 121 that is continuous with the bonding surface with the triangular prism 126, and a surface 129 that is an example of a non-contact surface that is not in contact with the triangular prism 126 that is continuous with the step portion 121. The surface 129 is a reflecting surface as an example of reflecting means (hereinafter, this reflecting surface is also denoted by reference numeral 129). A groove 122 is formed in the light separation element 123 adjacent to the end of the bonding surface of the triangular prism 126 and the prism 127 on the objective lens side (not shown).
[0170]
  The first1Also in the optical pickup device of the embodiment, the eighthReference exampleIn the same manner as the optical pickup apparatus, the second laser light that is emitted from the second light source, reflected by the reflecting surface 129, and incident on the light receiving surface of the second light source light monitor (not shown) is incident on the reflecting surface 129. When the angle is ψ and the refractive index of the prism 127 is n, the relationship of Equation (6) (n × sin ψ ≧ 1) is established between n and ψ so that the reflection surface 129 becomes a total reflection surface. .
[0171]
  Above1According to the optical pickup device of the embodiment, the reflecting surface 129 of the prism 127 is formed by cutting the end portion of one side surface of the triangular prism. Therefore, the angle of ψ can be adjusted by adjusting the cutting portion. Can also be adjusted easily. Accordingly, the second light source light monitor (not shown in FIG. 12) can be disposed at a location convenient for downsizing the optical pickup device.
[0172]
  (No.2Embodiment)
  FIG.2It is sectional drawing of the light separation element with which the optical pick-up apparatus of embodiment is provided. The light separating element 133 includes a part of one side surface of the prism 136 arranged on the first light source (not shown) side and a side surface of the triangular prism 137 arranged on the second light source (not shown) side. Are pasted together.
[0173]
  First2The light separating element 133 included in the optical pickup device of the embodiment is the prism 136 on the first light source side that has a shape such that the end of one side surface of the triangular prism is cut off. The light source side prism 127 (see FIG. 12) has a shape in which the end of one side surface of the triangular prism is cut.1This is essentially different from the light separation element 123 provided in the optical pickup device of the embodiment.
[0174]
  In FIG. 13, reference number 131 indicates a step portion connected to the bonding surface of the prism 136 with the triangular prism 137, and reference number 135 indicates a surface that is not in contact with the triangular prism 137 connected to the step portion 131 of the prism 136. Indicates.
[0175]
  On the other hand, reference numeral 139 indicates a non-contact surface with the prism 136 of the triangular prism 137 facing the non-contact surface 135, and is a reflection surface as an example of a reflection means.
[0176]
  Above2According to the optical pickup device of the embodiment, the prism 136 on the first light source side is formed by cutting the end of one side surface of the triangular prism, so that the step 131 has a second light source (not shown) side. Edge 136a is the first1Laser light is not scattered like the edge 127a of the step part 121 of the light separation element 123 provided in the optical pickup device of the embodiment. Therefore, the second1Unlike the optical pickup device of the embodiment, the laser light scattered by the edge 127a does not become unnecessary stray light.
[0177]
  (No.3Embodiment)
  FIG.3It is sectional drawing of the light separation element with which the optical pick-up apparatus of embodiment is provided. The light separating element 143 includes a part of one side surface of the triangular prism 146 arranged on the first light source (not shown) side and one side surface of the triangular prism 147 arranged on the second light source (not shown) side. Are bonded together with an adhesive. The adhesive layer formed of the adhesive 145 has a thickness of several microns to several tens of microns.
[0178]
  A wavelength selection film (not shown) is formed on the bonding surface of the triangular prism 146 with the triangular prism 147.
[0179]
  The end surface on the objective lens side (not shown) of the adhesive layer is the bottom surface of the groove 141. A side surface 149 of the groove 141 on the triangular prism 147 side is a reflecting surface as an example of a reflecting means.
[0180]
  Above3According to the optical pickup device of the embodiment, the first1And second2Unlike the optical pickup device of the embodiment, since it is not necessary to cut the triangular prisms 127 and 136 to form the light separating elements 123 and 133, the light separating element 143 can be manufactured easily and inexpensively.
[0181]
  (First1 Reference example)
  FIG. 15 shows the first1 Reference exampleIt is a fragmentary sectional view of the optical pick-up apparatus. First1 Reference exampleIn the optical pickup apparatus shown in FIG. 11, the reflection film is not provided, the triangular prism 157 on the second light source (not shown) side, and the triangular prism (not shown) on the first light source (not shown) side. And the refractive index of the triangular prism 157 on the second light source side as n, and the normal line of the bonding surface with the triangular prism 157 in the triangular prism on the first light source side, as shown in FIG. The inclination of the second laser light that has not been diffracted by the hologram pattern 68a with respect to the optical axis (the central axis of the light beam) 152 is θa, and is emitted from a second light source (not shown) and first-order diffracted by the hologram pattern 68a. Furthermore, the primary pattern of the hologram pattern 68a of the second laser beam that is reflected by the non-contact portion of the triangular prism 157 with the triangular prism on the first light source side and incident on the second light source light monitor. When the diffraction angle of light 151 and [theta] h, these n, between [theta] h and .theta.a, except that it holds the relationship of the following equation (7), essentially fifthReference exampleDifferent from the optical pickup device.
[0182]
      n × sin (θa + (sin^-1(Sin θh / n))) ≧ 1 (7)
  Equation (7) indicates that the first-order diffracted light 151 diffracted by the hologram pattern 68a of the second laser light is totally reflected by a non-contact portion 159 as an example of a non-contact surface with the triangular prism on the first light source side of the triangular prism 157. It is a condition to do. First1 Reference exampleIn the optical pickup device, the non-contact portion 159 is an example of a reflecting means.
[0183]
  The first1 Reference exampleIn the optical pickup device of the fifth,Reference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0184]
  In the above configuration, the first-order diffracted light 151 emitted from the second light source and diffracted by the hologram pattern 68a is totally reflected by the non-contact portion 159 and enters a second light source light monitor (not shown).
[0185]
  The first1 Reference exampleAccording to the optical pickup apparatus, since the relationship of the above formula (7) is set between n, θh, and θa, the first-order diffracted light 151 diffracted by the hologram pattern 68a of the second laser light is changed to the non-contact portion 159. It is possible to reflect almost 100%. Therefore, the amount of the second laser light incident on the second light source light monitor can be increased.
[0186]
  (First2 Reference examples)
  FIG. 16 shows the first2 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus. First2 Reference examplesIn this optical pickup device, instead of forming the light separating element by bonding two triangular prisms, the light separating element 163 is processed by processing a parallel plate type transparent integrated member made of synthetic quartz or BK-7. Only the points formed are the firstReference exampleDifferent from the optical pickup device.
[0187]
  First2 Reference examplesIn the first optical pickup device, the firstReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0188]
  A wavelength selection film 168 is formed by vapor deposition on the surface of the light separation element 163 facing the first light source 1. This wavelength selection film is designed to substantially totally reflect the first laser light having the wavelength λ1 emitted from the first light source 1 and to substantially transmit the second laser light having the wavelength λ2 incident from the second light source 2. ing.
[0189]
  Further, a reflective film 169 as an example of a reflecting means is formed on a portion of the surface facing the second light source 2 of the light separating element 163 on the side close to the objective lens (not shown).
[0190]
  The reflection film 169 is formed of a mirror on which a metal such as Al or a dielectric is deposited so that the reflectance is not affected even if the wavelength of the second laser light emitted from the second light source 2 fluctuates due to a temperature change or the like. Has been.
[0191]
  The first2 Reference examplesAccording to this optical pickup apparatus, the wavelength selection film 168 is provided on the surface of the parallel plate type light separation element 163 facing the first light source 1, while the reflection film 169 is provided on the surface of the parallel plate type light separation element 163. Since the light source is provided on the surface facing the two light sources, the wavelength selection film 168 and the reflection film 169 can be formed in separate steps as in the case where the light separation element is formed by two separate members. Therefore, as in the case where the light separating element is formed by two separate members, the problem that occurs in the conventional method of forming the reflective film on the wavelength selective film after forming the wavelength selective film on one side of the triangular prism. In other words, the problem of changing the wavelength selective film by applying film stress to the underlying wavelength selective film in the vapor deposition process for forming the reflective film, or the underlying wavelength selective film due to heat and work handling during the deposition of the reflective film It is possible to avoid the problem of damaging the light, improve the manufacturing yield of the transparent integrated member, and reduce the manufacturing cost of the light separating element.
[0192]
  In addition, since the light separation element 163 is formed from a parallel flat plate-type transparent integrated member, the bonding step can be omitted and the optical polishing surface can be reduced compared to a light separation element of a type in which two prisms are bonded. There can be only two surfaces facing the first and second light sources. Therefore, the manufacturing cost of the light separation element 163 can be significantly reduced.
[0193]
  The first2 Reference examplesIn this optical pickup device, the light separating element 163 is formed of a parallel plate type transparent integral member, but the light separating element is a wedge-shaped transparent integral member made of synthetic quartz or BK-7 or the like. It may be formed from a non-parallel flat plate-type transparent integral member made of synthetic quartz or BK-7, and in this case, the same effect as that obtained when a parallel plate-type transparent integral member is used can be obtained.
[0194]
  (First3 Reference examples)
  FIG. 17A shows the first3 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus. First3 Reference examplesIn the optical pickup apparatus of FIG. 1, the first point is that the film characteristics of the wavelength selection film 178 are not uniform.Reference exampleDifferent from the optical pickup device.
[0195]
  First3 Reference examplesIn the first optical pickup device, the firstReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0196]
  First3 Reference examplesIn the optical pickup device, the position at which the reflectance of the first laser beam emitted from the first light source 1 and reflected by the wavelength selection film 178 is maximum in the wavelength selection film 178 is the position of the reflection film 9 in the wavelength selection film 178. The part is opposed to the center position.
[0197]
  FIG. 17B is a diagram illustrating the relationship between the incident angle of the first laser light incident on the wavelength selection film 178 and the reflectance of the first laser light with respect to the wavelength selection film 178.
[0198]
  17B shown in FIG. 17B indicates the incident angle of the first laser light 171 that enters the portion of the wavelength selection film 178 that faces the center position of the reflection film 9, and θ32 indicates the first light source in the wavelength selection film 178. The incident angle of the 1st laser beam 172 with respect to the part near the 1 side is shown.
[0199]
  As shown in FIG. 17B, the reflectance of the first laser beam with respect to the wavelength selection film 178 is maximized at a portion of the wavelength selection film 178 facing the center position of the reflection film 9. The reflectivity decreases as the first light source 1 is moved from the portion facing the center position of the reflective film 9.
[0200]
  The first3 Reference examplesAccording to the optical pickup apparatus, the reflectance of the first laser beam with respect to the wavelength selection film 178 is maximized at a portion of the wavelength selection film 178 facing the center position of the reflection film 9, so that the wavelength selection film 178 is transmitted. The slight first laser beam can be minimized at a portion of the wavelength selection film 178 facing the center position of the reflection film 9. Therefore, a small amount of the first laser light emitted from the first light source 1 and transmitted through the wavelength selection film 178 reaches the reflection film 9 as the reflection means, and is reflected by the reflection film 9 to become stray light. The slight first laser light that passes through the selection film 178 and is reflected by the reflection film 9 disturbs the wavefront of the light beam of the first laser light reflected by the region of the wavelength selection film 178 that faces the center position of the reflection film 9. The problem can be avoided and the wavefront aberration of the light flux of the first laser light can be kept good. Of the light that passes through the wavelength selection film 178, the slight first laser light that passes through the first light source 1 side of the wavelength selection film 178 only passes through the triangular prism 7 and does not cause a problem.
[0201]
  The first3 Reference examplesIn the optical pickup apparatus, the reflectance of the first laser light with respect to the wavelength selection film 178 is maximized at a portion of the wavelength selection film 178 that faces the center position of the reflection film 9, but the wavelength selection film 178 of the first laser light. If the maximum position of the reflectance with respect to the wavelength selective film 178 is provided in the region facing the reflective film 9, the first3 Reference examplesThe same effect as that of the optical pickup device can be obtained.
[0202]
  (First4 Reference examples)
  FIG. 18 shows the first4 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus. First4 Reference examplesThis optical pickup device includes a prism 187 on the second light source 2 side having a square (substantially trapezoidal) cross section in a direction perpendicular to the column direction and one side surface of the triangular prism 186 on the first light source (not shown) side. The light separating element 183 is formed by pasting together the side surface having the largest area, and only the first point is that the light separating element is replaced.Reference exampleDifferent from the optical pickup device.
[0203]
  First4 Reference examplesIn the first optical pickup device, the firstReference exampleThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0204]
  The prism 187 is formed by cutting one corner of a triangular prism.
[0205]
  A reflection film 189 as a reflection means is formed on the side surface having the smallest area facing the side surface having the largest area of the light separating element 183, and a wavelength selection film 188 is formed on the one side surface of the triangular prism 186. ing. The reflection surface 189 is formed of a mirror or the like on which a metal such as Al or a dielectric is deposited.
[0206]
  In FIG. 18, reference numeral 181 indicates an example of the optical path of the second laser light that is emitted from the second light source 2, reflected by the reflective film 181, and then incident on the second light source light monitor 5.
[0207]
  The first4 Reference examplesAccording to the optical pickup apparatus, the reflecting film 189 as the reflecting means is provided on the side surface having the smallest area facing the side surface having the largest area of the prism 187. The angle α formed by the side surface having the smallest area or the incident angle θ of the second laser light emitted from the second light source 2 and incident on the reflection surface 189 with respect to the reflection surface 89 is defined as the side surface of the prism 187 on the second light source side. And the angle β formed by the wavelength selection film 188 of the light separation element 183 can be set independently. Accordingly, a degree of freedom arises in the place where the second light source light monitor 5 is arranged, and the optical pickup device can be downsized.
[0208]
  The first4 Reference examplesIn this optical pickup device, the reflecting film 189 as the reflecting means is formed by providing a mirror or the like on which the metal or dielectric such as Al is deposited on the side surface of the prism 187 where the area is the smallest. Although a high reflectance with respect to the reflective film 189 has been obtained, the reflective surface may be a material surface made of the same material as that of the prism 187 if a sufficient amount of light can be taken into the second light source light monitor 5. This is because even if the material surface, which is the material of the prism, is used as a reflecting means, a few percent of the second laser light incident on the material surface is reflected by this material surface according to the optical Fresnel formula. It is. As described above, in the conventional optical pickup device, the second laser light from the second light source is reflected by the wavelength selection film by several percent and guided to the second light source optical monitor. Even if the surface is used as the reflecting means, the second light source monitor can detect a light amount comparable to the light amount of the second laser light detected by the second light source monitor of the conventional optical pickup device.
[0209]
  If the material surface, which is the material of the prism, is used as the reflecting means, the reflecting means can be easily formed by simply cutting and polishing one corner of the triangular prism, greatly increasing the manufacturing cost of the light separating element. Can be reduced.
[0210]
  (First5 Reference examples)
  FIG. 19 shows the first5 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus. First5 Reference examplesIn the optical pickup apparatus, a half-wave film 190 as an example of polarization conversion means is disposed between the surface of the prism 187 on the second light source 2 side facing the second light source 2 and the second light source 2. The incident angle of the second laser light incident on the second light source light monitor 5 after being emitted from the second light source 2 and passing through the half-wave film 190 and reflected by the reflection film 189 is θb And when the refractive index of the prism 187 is n, the following equation (8) is approximately established between θb and n.4 Reference examplesDifferent from the optical pickup device.
[0211]
            tanθi = n (8)
  First5 Reference examplesIn the first optical pickup device, the first4 Reference examplesThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0212]
  The crystal axis orientation of the half-wave plate 190 is such that the linearly polarized second laser light emitted from the second light source 2 is substantially S-polarized with respect to the reflecting surface 189. Is set to
[0213]
  The first5 Reference examplesAccording to this optical pickup apparatus, a half-wave film 190 as an example of polarization conversion means is disposed between the surface of the prism 187 on the second light source 2 side facing the second light source 2 and the second light source 2. In this half-wave film 190, the linearly polarized second laser light emitted from the second light source 2 is polarized to substantially S-polarized light with respect to the reflecting surface 189, so that the second laser light incident on the reflecting surface Becomes substantially S-polarized light. Therefore, since the reflectance of S-polarized light is higher than that of P-polarized light, more second laser light can be guided to the second light source light monitor 5.
[0214]
  Further, when the incident angle of the second laser light incident on the second light source light monitor 5 with respect to the reflection film 189 is θb and the refractive index of the prism 187 is n, an approximate expression ( Since the relationship of 8) is established, θb can be set to the Brewster angle, and the reflectance of P-polarized light at the reflective film 189 can be made zero. Therefore, since the light condensed on the optical disk is the S-polarized component (stimulated emission component) having the same wavelength and the same phase in the second laser light, the second laser light emitted from the second light source 2 It is possible to prevent the spontaneous emission component, which is a slightly included P-polarized component, from entering the second light source monitor. Therefore, only the emission output of the stimulated emission component of the second laser light used when actually recording data on the optical disk or reading data from the optical disk can be detected by the second light source monitor 5.
[0215]
  The first5 Reference examplesIn this optical pickup device, the half-wave film 190 is disposed between the second light source and the reflective film in order to cause the stimulated emission component, which is the S-polarized component of the second laser light, to enter the reflective film 189. Instead of using the one-wavelength film 190, the second light source 2 may be a TM mode semiconductor laser so that S-polarized light may be incident on the reflective film 189. Here, the TM mode semiconductor laser device is a semiconductor laser device that emits laser light whose polarization direction is perpendicular to the active layer of the semiconductor laser device that emits laser light. For semiconductor lasers in the wavelength band of 630 to 650 nm, both laser devices in the TM mode whose polarization direction is perpendicular to the active layer or the TE mode parallel to the active layer have already been put into practical use. Therefore, by selecting a semiconductor laser device that can oscillate TM laser light as the light source among the above two modes, the second laser light incident on the reflecting means can be S-polarized light. If a TM mode semiconductor laser device is used instead of the half-wave film 190 to obtain S-polarized light, a relatively expensive polarization conversion element such as the half-wave film 190 can be omitted. The cost of the pickup device can be reduced, and the optical pickup device can be made compact.
[0216]
  (First6 Reference examples)
  FIG. 20 shows the first6 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus. First6 Reference examplesThe first optical pickup apparatus shown in FIG. 18 has a concave reflecting surface 209 as an example of the reflecting means of the prism 207 on the second light source 2 side.4 Reference examplesDifferent from the optical pickup device.
[0217]
  First6 Reference examplesIn the first optical pickup device, the first4 Reference examplesThe same reference numerals are given to the same components as those of the optical pickup device, and the description thereof will be omitted.
[0218]
  The concave reflecting surface 209 is a material surface of the same material as that of the prism 207.
[0219]
  The first6 Reference examplesAccording to the optical pickup apparatus, since the reflecting surface 209 as an example of the reflecting means is concave, the diverging light that is the second laser light emitted from the second light source 2 is secondly reflected by the reflecting surface 209 that is a concave surface. The divergent light, which is the second laser light emitted from the second light source 2 by the action of the concave reflecting surface 209, can be reflected toward the light receiving surface of the light source light monitor 5, and at the same time the second light source light monitor 5 It can be converged on the light receiving surface. Therefore, a larger amount of the second laser light can be incident on the second light source light monitor 5.
[0220]
  The first to first6 Reference examples and first to third embodimentsHas been explained in the optical pickup deviceReference examples and the present inventionMultiple optical pickup devicesPart ofMinutesIn the present inventionAn optical pickup device of a new embodiment may be configured in combination. In the case of such an optical pickup device, a plurality ofPart ofThe optical pickup device can be made even higher quality by the synergistic effect of the minute.
[0221]
【The invention's effect】
  As is clear from the above, according to the optical pickup device of the present invention, the first laser light emitted from the first light source is reflected toward the objective lens, and the second laser light emitted from the second light source is reflected. Since the wavelength selection film that is transmitted and incident on the objective lens and the reflecting means that transmits the second laser light emitted from the second light source and that is incident on the objective lens are arranged so as not to come into contact with each other. By appropriately adjusting the positions of the film and the reflecting means, all of the second laser light emitted from the second light source and incident on the wavelength selection film can be transmitted toward the objective lens. Therefore, unlike the conventional optical pickup device, it is not necessary to reflect the second laser beam by several% with the wavelength selection film, so that the amount of the second laser beam condensed on the data recording surface of the optical disk via the objective lens is increased. Thus, the data reproducing ability and data recording ability of the optical disc can be improved.
[0222]
  Further, since the wavelength selection film and the reflection means are provided so as not to contact each other, the wavelength selection film and the reflection means can be formed in separate steps. Therefore, the problem that occurs in the conventional optical pickup device in which after forming the wavelength selection film on one side of the triangular prism, the reflection film as the reflection means is formed on the wavelength selection film, that is, the reflection film as the reflection means. The problem of changing the wavelength selective film by applying a film stress to the underlying wavelength selective film in the vapor deposition process of forming a film, or damage to the underlying wavelength selective film due to heat or work handling during the deposition of the reflective film Problems can be avoided, the manufacturing yield of the light separating element can be improved, and the manufacturing cost of the light separating element can be reduced.
[Brief description of the drawings]
FIG. 1 shows the first of the present invention.Reference exampleIt is sectional drawing of the optical pick-up apparatus.
FIG. 2Reference exampleIt is an enlarged view of the bonding surface vicinity of the two triangular prisms which comprise the light separation element with which this optical pick-up apparatus is provided.
FIG. 3 shows the second of the present invention.Reference exampleIt is sectional drawing of the optical pick-up apparatus.
FIG. 4 is a third view of the present invention.Reference exampleIt is sectional drawing of the optical pick-up apparatus.
FIG. 5 shows the fourth of the present invention.Reference exampleIt is sectional drawing of the optical pick-up apparatus.
FIG. 6 shows the fifth of the present invention.Reference exampleIt is sectional drawing of the optical pick-up apparatus.
FIG. 7 shows the sixth aspect of the present invention.Reference exampleIt is sectional drawing of the optical pick-up apparatus.
FIG. 8 shows the seventh aspect of the present invention.Reference exampleIt is a fragmentary sectional view of the optical pick-up apparatus.
FIG. 9 shows the eighth embodiment of the present invention.Reference exampleIt is a fragmentary sectional view of the optical pick-up apparatus.
FIG. 10 shows the ninth aspect of the present invention.Reference exampleIt is sectional drawing of the light separation element with which the optical pick-up apparatus of FIG.
FIG. 11 shows the tenth aspect of the present invention.Reference exampleIt is sectional drawing of the light separation element with which the optical pick-up apparatus of FIG.
FIG. 12 shows the first of the present invention.1It is sectional drawing of the light separation element with which the optical pick-up apparatus of embodiment is provided.
FIG. 13 shows the first of the present invention.2It is sectional drawing of the light separation element with which the optical pick-up apparatus of embodiment is provided.
FIG. 14 shows the first of the present invention.3It is sectional drawing of the light separation element with which the optical pick-up apparatus of embodiment is provided.
FIG. 15 shows the first of the present invention.1 Reference exampleIt is a fragmentary sectional view of the optical pick-up apparatus.
FIG. 16 shows the first of the present invention.2 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus.
FIG. 17 (A) shows the first of the present invention.3 Reference examplesFIG. 17B is a diagram showing the relationship between the incident angle of the first laser light with respect to the wavelength selection film and the reflectance of the first laser light with respect to the wavelength selection film. .
FIG. 18 shows the first of the present invention.4 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus.
FIG. 19 shows the first of the present invention.5 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus.
FIG. 20 shows the first of the present invention.6 Reference examplesIt is a fragmentary sectional view of the optical pick-up apparatus.
FIG. 21 is a cross-sectional view of a conventional optical pickup device.
[Explanation of symbols]
  1 First light source
  2 Second light source
  3,23,33,53,83,93,103,113,123,133,143,163,173,183,203 Light separating element
  4 Objective lens
  5 Light monitor for second light source
  6,7,17,57,86,97,107,116,117,126,137,146,147,157,176,186 Triangular prism
  8,88,118,168,178,188 Wavelength selective film
  9,59,89,189 Reflective film
  10 Optical disc
  14,145 Adhesive
  19,29 Reflective diffraction grating
  24, 25, 63, 64
  41,42 Focusing point
  68 Hologram element
  68a Hologram pattern
  87 Right angle prism
  87a side
  96,106,127,136,187,207 prism
  99,109,119,129,139,149,169,209 Reflecting surface
  101 Cut surface
  106b First and second laser light emission surfaces
  121,131 steps
  135 Non-contact surface
  151 First-order diffracted light
  159 Non-contact part
  190 Half-wave film

Claims (6)

A first light source that emits a first laser beam;
A second light source that emits a second laser beam having a wavelength different from that of the first laser beam;
An objective lens for condensing the first and second laser beams on the data recording surface of the optical disc;
An optical monitor for detecting the amount of the second laser beam;
A wavelength selection film that reflects the first laser light emitted from the first light source toward the objective lens and transmits the second laser light emitted from the second light source to be incident on the objective lens; And a light separating element that is formed so as not to contact the wavelength selective film, and has a reflecting means for reflecting the second laser light emitted from the second light source toward the optical monitor ,
The first prism with the wavelength selection film sandwiched between at least a part of one side of the first prism on the first light source side and at least a part of one side of the second prism on the second light source side Bonding at least part of one side surface and at least part of one side surface of the second prism on the second light source side,
The reflecting means is disposed on the second prism;
Said reflecting means, the optical pickup apparatus according to claim noncontact surface der Rukoto provided in a part of the one side face side of the first prism of the one side face the second prism so as not to contact the. The optical pickup device according to claim 1 ,
The second prism is a triangular prism,
In addition, by forming the first prism into a shape in which a corner of the triangular prism on the non-contact surface side is cut so as to be substantially parallel to the optical axis of the second laser light incident on the objective lens, An optical pickup device, wherein the non-contact surface is formed on a second prism. The optical pickup device according to claim 1 ,
The optical pickup device, wherein the first and second prisms are triangular prisms. The optical pickup device according to claim 1 ,
The first prism is formed of a triangular prism, and the second prism has a surface that is non-contact with the first prism connected to the bonding surface with the first prism via a step portion. Pickup device. The optical pickup device according to claim 1 ,
The second prism is formed of a triangular prism,
The optical pickup device according to claim 1, wherein the first prism has a surface that is not in contact with the second prism connected to the bonding surface with the second prism via a stepped portion. The optical pickup device according to claim 1 ,
The first prism is composed of a first triangular prism, and the second prism is composed of a second triangular prism,
An optical pickup device, wherein at least part of one side of the first triangular prism and part of one side of the second triangular prism are bonded together through an adhesive layer.

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