JP4500125B2 - Optical head and optical information medium driving device - Google Patents

Description

  The present invention relates to an optical head, an optical information medium driving device, and a sensor, and in particular, a small sensor for detecting the tilt and position of an optical information medium, an optical head provided with this sensor, an optical information medium driving device, and an optical head. In particular, the present invention relates to a sensor for detecting the inclination and position of an optical component that needs to be displaced among the components constituting the optical head, and an optical head and an optical information medium driving device provided with the sensor.

  In the information age, high-density and large-capacity memory technology is actively developed. As the capacity required for the memory, in addition to high density, large capacity and high reliability, a rewriting function and the like can be mentioned, and an optical disk satisfies these requirements. In the optical head for optically recording / reproducing information on the optical disc, many reports have been made on the technology for detecting the tilt of the optical disc. For example, the device described in Patent Document 1 is intended to solve the problem of cost increase caused by arranging an LED (Light Emitting Diode) and a pair of photodetectors and difficulty in miniaturization.

  FIG. 18 is a diagram illustrating the configuration of the optical head disclosed in Patent Document 1, and the configuration and operation will be described below.

  In FIG. 18, 1 is a semiconductor laser (hereinafter referred to as LD) as a light source, 2 is a light beam emitted from the LD 1, 4 is a beam splitter as a separating means for separating a reflected light beam from the optical disk 6 and an emitted light beam, and 7 An aperture restricting means for restricting the aperture of the incident light beam to the objective lens 5 as a condensing means, 9 is a light spot condensed on the information recording surface of the optical disc 6 by the light flux 2 emitted from the LD 1, and 10 is the optical disc 6 Is a light detector that receives and photoelectrically converts a light beam reflected by the objective lens 5 and the beam splitter 4, 40 is a lens optical axis of the objective lens 5, and 8 is a light beam emitted from the LD 1 that passes through the aperture limiting means 7. Then, an unnecessary light beam other than the effective light beam 2 incident on the objective lens 5 (tilt detection light beam, that is, a tilt detection light beam of the optical disk 6), 17 is an unnecessary light beam 8. A light spot collected on the information recording surface of the disk 6, 14 is a light detector for tilt detection as a second light detecting means for receiving the reflected light beam of the unnecessary light beam 8 from the optical disk 6, and 90 is an unnecessary light beam 8. This is a reflection mirror as a traveling direction changing unit that changes the traveling direction of a part of the light beam and enters the objective lens 5 through the aperture limiting unit 7. The tilt detection light detector 14 has two detection areas 14 a and 14 b, and outputs from the respective areas 14 a and 14 b are respectively supplied to a subtractor 15. The output of the tilt detection light detector 14 is used to detect the angle formed by the optical axis of the objective lens 5 and the information recording surface of the optical disk 6, that is, the inclination of the optical disk 6.

  The operation for detecting the tilt of the optical disc 6 will be described with reference to FIG. Of the divergent light beam from the LD 1, the effective light beam 2 determined by the aperture limit 7 is used for recording / reproduction of the optical disk 6. The traveling direction of a part of the other unnecessary light beam 8 is changed by the reflecting mirror 90, passes through the aperture limiting means 7, and the focused spot 17 is irradiated onto the optical disk 6 by the objective lens 5. The focused spot 17 is irradiated to a position different from the focused spot 9 for recording / reproducing. The reflected light beams from the optical disc 6 at the focused spots 9 and 17 are imaged at different positions and received by the light detector 10 and the light detector 14, respectively. The light detector 14 is for detecting a tilt (optical disc tilt) and is a two-split light detector including detection regions 14a and 14b. When the optical disc 6 is perpendicular to the optical axis of the objective lens 5, the photodetector 14 is arranged so that the amount of light received by the condensing spot 17 by the light beam 8 for tilt detection is equal between the detection region 14a and the detection region 14b. Keep it. In FIG. 18, the radial direction of the optical disk 6 is along the X axis. When the rotation axis of the optical disc 6 is tilted with respect to the Y axis (around the Y axis), the tilt detection light beam 8 moves in the ± X direction on the photodetector 14. Therefore, by applying a calculation process {(the amount of received light of the detection region 14a) − (the amount of received light of the detection region 14b)} for obtaining the difference between the amount of received light of the detection region 14a and the amount of received light of the detection region 14b, the inclination of the optical disc 6 is increased. Can be detected. This tilt information is output from the subtracter 15 as a tilt signal VTILT. As described above, the tilt detection light beam can be obtained without using another light source such as an LED simply by disposing the reflection mirror 90 in the unnecessary light beam of the LD 1 that was not originally used.

It should be noted that, here, elements that are not based on the gist of the present invention, such as an actuator, a motor, a circuit, and a mechanism, which are other constituent elements constituting the optical information medium driving device to which the optical head is applied, are not shown. The explanation is also omitted.
Japanese Patent Publication No. 7-82657

  However, the configuration of Patent Document 1 has the following problems. That is, in the configuration of FIG. 18, since another light source such as an LED is not used to obtain the tilt detection light beam, the optical head can be reduced in size by the volume, but the light detector 14 uses the tilt detection light beam 8. Since the condensing spot 17 is imaged to receive light, the light detector 14 must be disposed in the vicinity of the light detector 10, and an unnecessary volume is required from the surface of the optical head. Further, since the unnecessary light beam 8 of the LD 1 is used, the amount of light and the degree of divergence of the tilt detection light beam vary depending on the characteristics of the individual LD 1, and the tilt (optical disc tilt) detection performance also varies. Further, in the positioning adjustment of the light detector 14, since the focused spot 17 is imaged and received, very high accuracy is required to adjust the received light amount in the detection area 14 a and the detection area 14 b to be equal. Is done. In addition, since the temperature in the vicinity of LD1 is the portion where the temperature rises most in the optical head, there is a high possibility that the position and direction of the luminous flux 8 from the LD1 will change due to temperature changes, and tilt (optical disc tilt) detection. There is also an error in performance. That is, although the size reduction and cost reduction by not requiring another light source such as an LED can be exhibited as an effect, the simplification cannot be achieved sufficiently, and the performance of tilt (optical disc tilt) detection cannot be sufficiently exhibited. Had.

  On the other hand, a so-called tilt sensor in which an LED is used as another light source and integrated with a light receiving element has been put into practical use. However, since this tilt sensor has a size of, for example, 7 mm × 7 mm and a height of about 9 mm, it is difficult to mount it on a small optical head.

  Thus, the present invention provides a small sensor with a simple configuration that sufficiently exhibits the performance of detecting the tilt of an optical disc and the positional deviation of an optical component, and further, an optical head and an optical information medium provided with this sensor. An object is to provide a drive device.

  In order to achieve the above object, the present invention is based on an optical head that collects information recording or reproduction light emitted from a laser light source on an optical information medium and receives reflected light from the optical information medium. As described above, a sensor for detecting an inclination or a positional deviation of the optical information medium with respect to a predetermined reference is provided, and the sensor is provided on a substrate, a light source chip element provided on the substrate, and the substrate. And a light receiving region that receives light emitted from the light source chip element and reflected by the optical information medium, the light receiving region being divided into a plurality of regions, and the light depending on the ratio of the amount of light received in each region. The information medium is configured to detect an inclination or positional deviation of the information medium.

  Further, the present invention presupposes an optical head that collects light emitted from a laser light source through a predetermined optical component and then collects the light on an optical information medium and receives reflected light from the optical information medium. A sensor for detecting a positional deviation of the optical component with respect to a reference is provided. The sensor is provided on a substrate, a light source chip element provided on the substrate, and provided on the substrate and emitted from the light source chip element. And a light receiving region that receives light reflected by the optical component or a holding member that holds the optical component, and the light receiving region is divided into a plurality of regions, and the optical component is divided according to the ratio of the amount of light received in each region. It is comprised so that the inclination or position shift of this may be detected.

  The present invention also provides light for receiving information reflected or reflected from the optical information medium after transmitting the information recording or reproducing light emitted from the laser light source to a predetermined optical component and then condensing it on the optical information medium. Assuming a head, a sensor for detecting the tilt or displacement of the optical component with respect to a predetermined reference is provided. The sensor includes a substrate, a light source chip element provided on the substrate, and a sensor on the substrate. A light receiving region that receives the reflected light reflected by the optical component or the holding member that holds the optical component, and the optical component or the holding member that holds the optical component. A reflection region for reflecting light emitted from the light source chip element is formed by a plurality of regions each having a different reflectance, and is reflected by the reflection region to be reflected in the light receiving region. It is configured to detect a tilt or positional deviation of the optical component in the received light amount of reflected light received.

  A recess may be formed on the surface of the substrate, and the light source chip element may be disposed in the recess.

  The side surface of the recess may be tapered.

  The light source chip element is preferably an LED element.

  The substrate may be made of a semiconductor, and the light source chip element may be formed integrally with the substrate.

  The substrate may be provided with a circuit unit for amplifying and calculating a photocurrent from the light receiving region.

  The optical information medium is formed in a disc shape, a cylindrical element is provided in an optical path between the optical information medium and the light receiving area, and the light receiving area extends in a direction parallel to the diameter direction of the optical information medium. It is good also as a structure divided | segmented on the boundary of a dividing line, and the said cylindrical element being arrange | positioned so that a bus line may become the direction inclined with respect to the said dividing line.

  The optical head may be an optical information medium driving device that includes the optical head and records information on the optical information medium or reproduces the recorded information.

  On the premise of a sensor for detecting an inclination or positional deviation of an object with respect to a predetermined reference, a substrate, a light source chip element provided on the substrate, a light source chip element provided on the substrate, and emitted from the light source chip element A light receiving area for receiving the light reflected by the object, and the light receiving area is divided into a plurality of areas so as to detect the inclination or displacement of the object according to the ratio of the amount of light received in each area. It is configured.

  Further, the present invention presupposes a sensor for detecting an inclination or positional deviation of an object with respect to a predetermined reference, a substrate, a light source chip element provided on the substrate, and provided on the substrate, A light receiving region that receives light emitted from the light source chip element and reflected by the object, and a plurality of reflection regions for reflecting light from the light source chip element on the object have different reflectances. The inclination or the positional deviation of the object is detected based on the amount of light received by the reflection region and received by the light reception region.

  As described above, in the optical head according to the present invention, the sensor includes the light receiving area divided into a plurality of areas and the light source chip element on the substrate, and the reflected light from the optical information medium is transmitted through the plurality of areas. The optical information medium is detected to detect the inclination or displacement of the optical information medium according to the amount of light received in the plurality of regions. For this reason, a simple sensor that fully exhibits the ability to detect the tilt and displacement of an optical information medium should be placed at a position that does not require high accuracy for positioning adjustment and does not affect the original shape of the optical head. Can do. In addition, since the tilt and the like are detected using a light source chip element different from the laser light source, the variation characteristics thereof are small, and the change in the position and direction of the light beam from the light source chip element due to the temperature change is also small. An optical head that can be reduced in size and cost can be realized.

  In the optical head according to another aspect of the present invention, the sensor includes a light receiving region divided into a plurality of regions and a light source chip element on a substrate, and reflects light from an optical component or a holding member that holds the optical component. Light is received in the plurality of regions, and the tilt or position of the optical component is detected according to the amount of light received in the plurality of regions. For this reason, it is possible to perform detailed control of the optical component whose displacement and position are displaced by the driving means in the optical head in accordance with the detected information. For example, for spherical aberration caused by the thickness of the optical disk, it is possible to correct the spherical aberration by controlling the position of the optical component in the optical head.

  In the optical head according to another aspect of the present invention, the sensor has a light receiving region and a light source chip element on the substrate for receiving light reflected by a reflective region formed by a plurality of regions each having a different reflectance. Since it is a structure provided, it is not necessary to divide the light receiving area of the sensor into a plurality of areas. As a result, it is possible to perform detailed position control of the optical component while reducing the size of the optical head.

  In addition, when a concave portion is formed in the substrate provided with the light receiving region, and the light source chip element is mounted in this concave portion, the light emitted from the light source chip element is irradiated onto the optical information medium, and the reflected light is incident on the light receiving region. By detecting the tilt or position of the optical information medium upon incidence, it has a simple configuration that sufficiently exhibits the performance of detecting the tilt or position of the optical information medium, and also removes unnecessary light of the light source chip element from the side surface portion of the recess. The detection ability as a sensor can be improved by reaching the above. Moreover, since it can suppress that a light source chip element protrudes from a board | substrate, the small sensor which is easy to handle as one component is realizable. Furthermore, by making the side surface of the recess tapered, the light source chip can be easily mounted and the substrate can be easily formed as compared with the case where the side surface of the recess is vertical. Can be configured to easily escape into the air.

  In addition, when the light source chip element is an LED element, it is easy to fix on the substrate and emits light stably, so that a small sensor with a simple configuration that sufficiently exhibits the ability to detect the tilt or position of the optical information medium. Can be realized.

  Further, when the substrate is made of a semiconductor, the light source chip element is integrally formed on the substrate by, for example, a process step, thereby generating an in-plane generated when a separate light source chip element is mounted on the substrate. Since there is no error in position and angle, it is possible to suppress variations in the optical axis tilt and light emission position of the light beam. Further, since the area of the recess for mounting the light source chip element can be reduced, the area of the light receiving chip can be increased accordingly. As described above, an optical head capable of detecting the tilt or position of the optical information medium with higher accuracy can be realized.

  In addition, when the circuit unit for amplifying and calculating the photocurrent from the light receiving area is provided on the substrate, the sensor output becomes more stable, so that the performance of detecting the tilt or position of the optical information medium is sufficiently exhibited. A small sensor can be realized with a simple configuration.

  Further, in the case where the reflected light from the optical information medium is incident on the light receiving region through the cylindrical element, the optical information medium has a simple configuration that sufficiently exhibits the performance of detecting the tilt or position of the optical information medium. Even in the case of an optical disc in which the reflectance differs between the recorded portion and the unrecorded portion, it is possible to realize a small sensor that stably detects the tilt or position without being affected by the reflectance.

  Further, the optical head of the present invention includes a laser light source, a condensing element driving means, and a light receiving element that receives signal reflected light from an optical information medium, and includes the above-described sensor. An optical head equipped with a small sensor can be realized with a simple configuration that sufficiently exhibits the performance of detecting the inclination and position of a component, for example, the light condensing element driving means.

  In the sensor according to the present invention, the light receiving area is divided into a plurality of areas, and the inclination or positional deviation of the object is detected based on the ratio of the amount of light received in each area. It can be set as a small sensor which can detect.

  In addition, the sensor according to another aspect of the present invention is configured to include a light receiving region and a light source chip element that receive light reflected by a reflective region formed by a plurality of regions each having a different reflectance, on a substrate. It is possible to detect the tilt or displacement of the object without dividing the light receiving area. Therefore, a simple and small sensor can be realized.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1A, FIG. 1B, and FIG. 1C are a plan view, a side view, and a front view showing an inclination sensor according to Embodiment 1 of the present invention. This figure shows a schematic configuration of the tilt sensor. 2A, 2B, and 2C are a plan view, a side view, and a front view showing an optical head on which the tilt sensor is mounted. This figure schematically shows the optical head. The configuration and function will be described below.

  1 (a), FIG. 1 (b), FIG. 1 (c), FIG. 2 (a), FIG. 2 (b), and FIG. 2 (c), reference numeral 6 is an example of an optical information medium that is a reflector. The optical disc is shown. The tilt sensor 38 includes a semiconductor substrate 30 having a rectangular shape in plan view and having a thickness of 0.3 mm, which is disposed at a position 3 mm from the optical disc 6. The semiconductor substrate 30 is a substrate made of a semiconductor such as silicon, GaAsP (gallium / arsenic / phosphorus), Ge (germanium), InGaAs (indium / gallium / arsenic). The semiconductor substrate 30 is provided with a light receiving chip as an example of a light receiving region. In the first embodiment, the light receiving chip is divided into two regions (first light receiving chip 31a and second light receiving chip 31b). The first light receiving chip 31a and the second light receiving chip 31b are divided with a dividing line 34 extending linearly as a boundary. Both the light receiving chips 31a and 31b are each made of a semiconductor having a size of 1.2 mm × 1.5 mm (the structure is not described in detail). That is, both the light receiving chips 31 a and 31 b are formed symmetrically with respect to the dividing line 34.

  The first light receiving chip 31a is provided with a first electrode 32a, and the second light receiving chip 31b is provided with a second electrode 32b. The semiconductor substrate 30 is provided with a third electrode 33 that acts in common on both the light receiving chips 31a and 31b.

  The semiconductor substrate 30 is provided with an LED chip 35 as an example of a light source chip element. The LED chip 35 is 0.31 mm × 0.21 mm and formed with a height of 0.35 mm. The LED chip 35 is disposed such that the light emitting point 37 is positioned on the extension line of the dividing line 34. The LED chip 35 is provided on the semiconductor substrate 30 via the fourth electrode 36. In FIG. 1B, reference numeral 11 denotes an emitted light beam emitted from the LED chip 35, and in FIG. 1A, reference numeral 12 denotes a reflected light beam reflected by the optical disk 6.

  The sensor 38 is configured by the above components. With this configuration, the sensor 38 has a size of 2.7 mm × 2.4 mm and a height of 0.65 mm. In the present embodiment, description will be given by taking an example in which this sensor is applied as an inclination sensor 38 for detecting the inclination of the optical disc 6.

  In FIG. 2, reference numeral 39 indicates a wiring board that is electrically connected to the tilt sensor 38. Here, the electrical connection to the wiring board 39 means that the third electrode 33 is connected and fixed to the wiring on the wiring board 39 by soldering, and the first electrode 32a, the second electrode 32b, the LED chip 35, and the fourth electrode 36 are connected. , Meaning that they are connected and fixed to the wiring on the wiring board 39 by wire bonding using metal wires (not shown).

  In the figure, reference numeral 42 denotes an objective lens as a condensing element, 43 denotes an actuator as condensing element driving means for driving the objective lens 42, 41 denotes a semiconductor laser as a laser light source, and 44 denotes a semiconductor. Optical system blocks on which optical elements for detecting the information signal of the optical disk 6 are shown, respectively, by causing the emitted light from the laser 41 to reach the objective lens 42. The optical head 45 on which the tilt sensor 38 is mounted is configured by the above components.

  Here, the R direction is the radial direction of the optical disc 6, and the T direction is the tangential direction of the optical disc 6. The tilt sensor 38 is arranged so that the dividing line 34 is substantially parallel to the T direction.

  The operation of the tilt sensor 38 configured as described above and the optical head on which the tilt sensor 38 is mounted will be described.

  First, the LED chip 35 energized by being connected to an external circuit (not shown) by the wiring board 39 emits light and emits divergent light as shown in FIGS. 1B and 1C. The emitted light beam 11 enters the optical disk 6 and is reflected. The reflected light beam 12 is incident on the tilt sensor 38 with a size as shown in FIG. The emitted light beam 11 emitted from the LED chip 35 is directly applied to the optical disc 6 without passing through the optical components, and the reflected light beam 12 is also directly incident on the light receiving chips 31a and 3b without passing through the optical components. The Here, the tilt sensor 38 is positioned so that the light amounts received by the light receiving chip 31a and the light receiving chip 31b are equal when the optical disc 6 does not generate a relative tilt with respect to a predetermined reference of the optical head 45. Yes.

  The light receiving chips 31a and 31b are electrically connected to the wiring of the wiring board 39 by the third electrode 33, and the first electrode 32a and the second electrode 32b are electrically connected to the wiring of the wiring board 39 by metal wires, respectively. Therefore, a photocurrent corresponding to the amount of light received by each of the light receiving chips 31a and 31b is output to the wiring. The light receiving chips 31a and 31b function as so-called two-divided photodiodes.

  The function of the tilt sensor 38 will be described with reference to FIGS. 3 (a), 3 (b), and 3 (c). FIGS. 3A, 3 </ b> B, and 3 </ b> C show the relationship between the tilt sensor 38 and the reflected light beam 12. These drawings do not show the wiring board 39 and its wiring for convenience. Instead, the photocurrent generated in the light receiving chips 31a and 31b is signal lines from the first electrode 32a and the second electrode 32b as an example of a circuit unit. It is shown as being input to the differential circuit 13.

  FIG. 3A shows a state where there is no relative inclination in the R direction (around the axis in the T direction) of the optical disk 6 with respect to the optical head 45 in FIG. In this state, since the reflected light beam 12 is positioned symmetrically with respect to the dividing line 34, the light receiving amounts of both the light receiving chips 31a and 31b are equal, and the photocurrents generated from the first electrode 32a and the second electrode B32b are also equal. Therefore, the R slope signal of the differential circuit 13 is “0”.

  FIG. 3B shows a state in which the optical disk 6 has a relative inclination in the + direction in the R direction (around the axis in the T direction) shown in FIG. In this state, since the reflected light beam 12 is shifted toward the first light receiving chip 31a with respect to the dividing line 34, the amount of light received by the first light receiving chip 31a is larger than the amount of light received by the second light receiving chip 31b. The photocurrent from 32a is larger than the photocurrent from the second electrode 32b. Therefore, the R slope signal of the differential circuit 13 is “+”.

  FIG. 3C shows a state where the optical disk 6 has a relative inclination in the R direction (around the axis in the T direction) with respect to the optical head 45. In this state, since the reflected light beam 12 is shifted toward the second light receiving chip 31b with respect to the dividing line 34, the amount of light received by the first light receiving chip 31a is smaller than the amount of light received by the second light receiving chip 31b. The photocurrent from 32a is smaller than the photocurrent from the second electrode 32b. Therefore, the R slope signal of the differential circuit 13 is “−”.

  In this manner, the tilt sensor 38 can output an R tilt signal corresponding to the relative tilt of the optical head 45 in the R direction (around the T direction axis) with respect to the optical disc 6. In other words, the tilt sensor 38 can detect the relative tilt of the optical head 45 and the optical disc 6 in the R direction (around the T direction axis).

  Two features according to the configuration of this embodiment will be described. One is that even if a relative tilt in the T direction (around the R direction axis) occurs in the optical head 45 and the optical disc 6, the reflected light beam 12 only shifts in the T direction, that is, along the dividing line 34. , The R slope signal will not change. The other is that even if the optical disk 6 is displaced in the focus direction, the center position of the reflected light beam 12 does not change and only the diameter changes. Therefore, if auto gain control is applied, the R tilt signal changes. There is nothing.

  As described above, even if the tilt sensor 38 of the first embodiment has a displacement in the focus direction of the optical disc 6 or a relative tilt in the T direction (around the axis in the R direction) between the optical head 45 and the optical disc 6, The relative inclination of the optical head 45 and the optical disc 6 in the R direction (around the T direction axis) can be detected without being affected.

  In addition, the tilt sensor 38 of the first embodiment and the optical head 45 on which the tilt sensor 38 is mounted also have the following effects. First, since the tilt sensor 38 is small, the shape of the optical head 45 is not affected. Further, the light source for detecting the relative inclination is the LED chip 35, and the variation characteristic is also small. Since the LED chip 35 and the light receiving chips 31a and 31b are integrated with the semiconductor substrate 30, precise positioning adjustment of the tilt sensor 38 on the optical head 45 is not necessary. Further, since the tilt sensor 38 can be disposed at a position farthest from the semiconductor laser 41, that is, the portion of the optical head where the temperature rises most, the influence of heat from the semiconductor laser 41 can be reduced. As a result, the outgoing light beam 11 from the LED chip 35 is less likely to change the position and orientation of the light beam due to temperature changes, and is less likely to cause an error in the relative tilt detection performance.

  Furthermore, since the light receiving area of the reflected light beam 12 can be made to function as the tilt sensor 38 only by being divided into two, it is possible to avoid a complicated configuration and to reduce the size of the tilt sensor 38.

  Although not shown, the optical head 45 of the first embodiment is provided with a tilt correction mechanism. The tilt correction mechanism is configured to drive and control the actuator 43 based on the output result from the tilt sensor 38. By the drive control of the actuator 43, the position of the objective lens in the focus direction and the tracking direction is corrected. Note that the tilt correction mechanism is not limited to the configuration for driving and controlling the actuator 43. For example, the tilt correction mechanism may be configured to perform position control or posture control of the optical head 45 itself.

(Embodiment 2)
In the first embodiment, after the semiconductor substrate 30 is formed, the LED chip 35 is mounted on the semiconductor substrate 30. However, in the second embodiment of the present invention, as shown in FIG. Are integrally formed on the semiconductor substrate 30 by process steps. FIG. 4 shows the sensor 38 according to the second embodiment in a section taken along line IV-IV in FIG.

The semiconductor substrate 30 has an N ⁺ semiconductor layer 30a containing a relatively high concentration of N-type impurities and an N ⁻ semiconductor layer 30b containing a relatively low concentration of N-type impurities. The impurity concentration of the N ⁻ semiconductor layer 30b is set sufficiently low, and substantially functions as a high-resistance intrinsic semiconductor.

An impurity diffusion region containing a P-type impurity at a relatively high concentration is provided on the N ⁻ semiconductor layer 30b. This impurity diffusion region constitutes the light receiving chips 31a and 31b. The first light receiving chip 31a and the second light receiving chip 31b have similar impurity concentration profiles, and as a result, the characteristics are substantially the same both optically and electrically. The fact that both the light receiving chips 31a and 31b are formed so as to have the same impurity concentration profile means that the light receiving chips 31a and 31b can be formed simultaneously.

  A third electrode 33 as a cathode electrode is deposited on the bottom surface (lower surface) of the semiconductor substrate 30. The third electrode 33 is connected to a cathode terminal (not shown). On the other hand, the upper surface of the semiconductor substrate 30 is covered with an insulating film 62 and a protective film 63. The first electrode 32a as an anode electrode is connected to the first light receiving chip 31a through a contact hole formed in the insulating film 62 and the protective film 63. The first electrode 32a is connected to an anode terminal (not shown). The second electrode 32b has the same configuration as the first electrode 32a and is connected to the second light receiving chip 31b.

  A vertical PIN diode is formed between the first electrode 32a, the second electrode 32b, and the third electrode 33, and this vertical PIN diode generates a photocurrent according to the amount of light received. By directly or indirectly detecting the photocurrent flowing through the vertical PIN diode, it is possible to know the amount of light applied to each of the light receiving chips 31a and 31b.

  A fourth electrode 36 made of a metal film is formed above the insulating layer 62, and a semiconductor layer 64 having a PN junction is formed above the fourth electrode 36. An insulating film 65 and a fifth electrode 66 are formed on the upper surface of the semiconductor layer 64 leaving the central portion. The central portion of the upper surface of the semiconductor layer is a light emitting point 37. With this configuration, the LED chip 35 is integrally formed on the semiconductor substrate 30.

  In the second embodiment, since there is no in-plane position and angle error that occurs when a separate LED chip is formed on the semiconductor substrate 30, it is possible to suppress variations in the optical axis tilt and emission position of the emitted light beam 11. Can do. Therefore, the optical head 45 that can detect the tilt of the optical disc 6 with higher accuracy can be realized.

  Other configurations, operations, and effects are the same as those in the first embodiment.

(Embodiment 3)
The configuration and operation of Embodiment 3 of the present invention will be described with reference to FIGS. 5 (a), 5 (b), and 5 (c).

  5 (a), 5 (b), and 5 (c) are a plan view, a side view, and a front view, respectively, of the tilt sensor 38 in the optical head 45 according to the third embodiment. The sensor 38 is shown schematically. The configuration and function will be described below. 5 (a), 5 (b), and 5 (c), the same components as those in FIGS. 1 (a), 1 (b), and 1 (c) are denoted by the same reference numerals. Only the points different from the first embodiment will be described here.

  A recess 61 is formed at the end of the semiconductor substrate 30, and the end where the recess 61 is formed is thinner than other portions. The recess 61 is formed by cutting away the surface (the right side in FIG. 5B) where the light receiving chips 31a and 31b are formed.

  The semiconductor substrate 30 has a thickness of 0.5 mm as a whole, but the thickness of the end portion where the recess 61 is formed is 0.2 mm. The LED chip 35 is mounted in the recess 61. Thereby, compared with Embodiment 1, since the height which the LED chip 35 protrudes from the semiconductor substrate 30 can be suppressed, handling of the inclination sensor 38 can be made easy.

  Since the side surface of the recess 61 is formed in a taper shape on the semiconductor substrate 30, an interval between the LED chip 35 and the light receiving chips 31 a and 31 b is necessary. Therefore, the inclination sensor 38 has a high height of 2.7 mm × 2.65 mm. The size is 0.55 mm.

  The schematic configuration of the optical head 45 on which the tilt sensor 38 is mounted is the same as that shown in FIGS. 2A, 2B, and 2C of the first embodiment. Therefore, the tilt sensor 38 according to the second embodiment of the present invention has the same function as that shown in FIGS. 3A, 3B, and 3C, and the R direction between the optical head 45 and the optical disc 6 ( The relative inclination around the axis in the T direction can be detected as an R inclination signal.

  In the third embodiment, since the LED chip 35 is provided in the recess 61, in addition to the features of the first embodiment, the LED chip 35 can be prevented from protruding from the semiconductor substrate 30, and the tilt sensor 38 can be set to 1 It can be easily handled as one part. In addition, since the side surface of the recess 61 is tapered, it is possible to prevent unnecessary light from the LED chip 35 from being reflected by the tapered portion of the recess 61 to reach the optical disk 6.

  In the third embodiment, the LED chip 35 may be formed integrally with the semiconductor substrate 30 in the process steps as in the second embodiment. Other configurations, operations, and effects are the same as those in the first embodiment.

(Embodiment 4)
The configuration and operation of Embodiment 4 of the present invention will be described with reference to FIGS. 6 (a), 6 (b), and 6 (c).

  6A, 6B, and 6C are a plan view, a side cross-sectional view, and a front cross-sectional view, respectively, of the tilt sensor 38 in the optical head according to the fourth embodiment. The tilt sensor 38 is schematically shown. The fourth embodiment further emphasizes the features of the third embodiment. Accordingly, in FIG. 6 (a), FIG. 6 (b), and FIG. 6 (c), the same components as those in FIG. 5 (a), FIG. 5 (b), and FIG. Only the differences from the third embodiment will be described.

  The semiconductor substrate 30 is configured to have a thickness of 0.5 mm as a whole, and a recess 61 is formed at the center of one surface of the semiconductor substrate 30 (the right side in FIG. 6B). On the surface where the recess 61 is formed, the light receiving chips 31a and 31b are formed so as to surround the recess 61 over substantially the entire surface. A recess 61 is formed in the central portion of the semiconductor substrate 30, and the LED chip 35 is disposed in the recess 61, so that the semiconductor substrate 30 has a flat plate shape as a whole.

  The thickness of the central portion where the recess 61 is formed is 0.2 mm. The LED chip 35 is mounted in the recess 61 so that the light emitting point 37 is located at the center thereof. Since the side surface of the recess 61 is formed in a tapered shape, a corresponding distance is required between the LED chip 35 and the light receiving chips 31a and 31b, and the inclination sensor 38 is 2.7 mm × 4.5 mm and has a height of 0.55 mm. It becomes size.

  The schematic configuration of the optical head 45 on which the tilt sensor 38 is mounted is the same as that in FIGS. 2A, 2B, and 2C of the first embodiment. Therefore, the tilt sensor 38 according to the fourth embodiment of the present invention has the same function as that shown in FIGS. 3A, 3B, and 3C, and is applied to the optical head 45 and the optical disc 6 in the R direction (T The relative inclination around the direction axis can be detected as an R inclination signal.

  The feature of the configuration of the fourth embodiment is more distinctive from the feature of the second embodiment in addition to the feature of the first embodiment. That is, since the LED chip 35 is provided in the recess 61 at the center of the substrate, in addition to the features of the first embodiment, the LED chip 35 can be prevented from protruding from the semiconductor substrate 30, and the tilt sensor 38 can be configured as one component. It has the characteristic that it can be made easy to handle. Moreover, by forming the side surface of the recess 61 in a tapered shape, unnecessary light from the LED chip 35 is difficult to reach the optical disk 6.

  In the fourth embodiment, the LED chip 35 may be formed integrally with the semiconductor substrate 30 in the process steps as in the second embodiment. Other configurations, operations, and effects are the same as those in the third embodiment.

(Embodiment 5)
The configuration and operation of Embodiment 5 of the present invention will be described with reference to FIGS. 7 (a), 7 (b), and 7 (c).

  FIGS. 7A, 7B, and 7C are a plan view, a side cross-sectional view, and a front cross-sectional view of the tilt sensor 38 in the optical head of the fourth embodiment. 38 shows a schematic configuration of 38. 7 (a), FIG. 7 (b), and FIG. 7 (c), the same components as those in FIG. 6 (a), FIG. 6 (b), and FIG. Only differences from the fourth embodiment will be described. The schematic configuration of the optical head 45 on which the tilt sensor 38 is mounted is the same as that shown in FIGS. 2A, 2B, and 2C of the first embodiment.

  A cylindrical element 46 that is a cylindrical lens is disposed between the tilt sensor 38 and the optical disc 6. The cylindrical element 46 has a substantially square shape in plan view, and is arranged such that the bus line is oriented at an angle of 45 degrees with respect to the dividing line 34 of the light receiving chips 31a and 31b. A through hole 46 a is formed at the center of the cylindrical element 46. The through hole 46a is for allowing the emitted light beam 11 emitted from the LED chip 35 to pass therethrough. That is, the emitted light beam 11 from the LED chip 35 toward the optical disk 6 does not pass through the cylindrical element 46. On the other hand, the reflected light beam 12 from the optical disk 6 passes through the cylindrical element 46. The cylindrical element 46 acts on the entire reflected light beam 12 incident on the first light receiving chip 31a and the second light receiving chip 31b. The cylindrical element 46 is most preferably arranged so that the bus line forms an angle of 45 degrees with respect to the dividing line 34 of the light receiving chips 31a and 31b. However, the effect is within the allowable range even when the angle is 40 degrees or more and 50 degrees or less. Can be obtained.

  Here, the case where the reflectance differs between the recorded portion and the unrecorded portion of the optical disc 6 will be described. The recorded part and the unrecorded part are adjacent to each other in the R direction of the optical disc 6 and have different reflectivities. For this reason, when the emitted light beam 11 from the LED chip 35 is irradiated onto the optical disk 6, the irradiation light beam 47 formed on the optical disk 6 becomes dark in the R direction half as shown in FIG. It will have a state. The emitted light beam 11 is reflected by the tilt sensor 38 in this state.

  As in the above-described fourth embodiment (see FIG. 6), if the tilt sensor 38 is not provided with a cylindrical element, the reflected light beam 12 has the brightness and darkness in the R direction as it is, so that it is more than the first light receiving chip 31a. The amount of light received by the second light receiving chip 31b decreases. That is, even when the optical head 45 and the optical disc 6 do not generate a relative tilt, an R tilt signal is output, so the relative tilt in the R direction (around the T direction axis) between the optical head 45 and the optical disc 6 is determined. It cannot be detected stably.

  On the other hand, according to the tilt sensor 38 of the fifth embodiment, the reflected light beam 12 reflected from the optical disk 6 having brightness in the R direction passes through the cylindrical element 46. At this time, the transmitted light beam 12 passes through the light beam cross section on the surface including the bus line without being changed, but the light beam cross section on the surface perpendicular to the bus line is converged by the lens effect. Then, the light beam 12 becomes divergent again after passing the focal position of the cylindrical element 46. At this time, since the cylindrical element 46 is a cylindrical lens arranged in a posture in which the generatrix is rotated by 45 degrees with respect to the R direction, the direction in which the light beams converge and diverge is also inclined by 45 degrees with respect to the R direction. As a result, in the divergent light beam, the light / dark boundary is rotated 90 degrees with respect to the light beam before transmission. The tilt sensor 38 is arranged at a position in the optical axis direction such that the divergent light beam has substantially the same size as the cross-section of the light beam in the plane including the generatrix that has not changed. As a result, the image of the light beam incident on the cylindrical element 46 becomes substantially circular when rotated 90 degrees at the position of the tilt sensor 38.

  Therefore, as shown in the fifth embodiment, the reflected light beam 12 reflected from the optical disk 6 with brightness in the R direction is rotated 90 degrees at the position of the tilt sensor 38 as shown in FIG. Thus, the light beam has a brightness in a direction perpendicular to the R direction. For this reason, the received light amounts of the first light receiving chip 31a and the second light receiving chip 31b divided by the dividing line 34 extending in the T direction are equal to each other, and the reflectance of the recording portion and the non-recording portion of the optical disc 6 is the same. Even if they are different, the R slope signal of the differential circuit 13 is not affected by the difference. That is, in the fourth embodiment, when the optical head 45 and the optical disc 6 do not have a relative tilt, an R tilt signal is output depending on the brightness of the irradiation light beam 47, and the optical head 45 and the optical disc 6 are transmitted in the R direction. It is possible to avoid a situation in which the relative inclination (around the axis in the T direction) cannot be detected stably.

  This operation will be described with reference to FIGS. FIG. 10 schematically shows the configuration of FIG. 7, and shows the trace of the light beam 11 emitted from the LED chip 35 and the light beam 12 reflected from the optical disk 6. FIG. 11 conceptually shows the distribution of the irradiation light beam 47 on the optical disc 6, and the irradiation light beam 47 includes a low reflectivity portion 47a as shown in FIG. The low reflectance part 47a shows a distribution extending in the T direction, for example.

  On the other hand, FIGS. 12A to 12C show the distribution of the reflected light beam 12 from the first light receiving chip 31a and the second light receiving chip 31b of the tilt sensor 38 and the optical disk 6 incident thereon. FIG. 12A shows a case where there is no tilt around the T axis, and FIGS. 12B and 12C show a case where the tilt around the T axis gradually increases. Similar to the irradiation light beam 47, the reflected light beam 12 also includes a low reflectance portion 12a. However, the distribution of the low reflectivity portion 12a in the tilt sensor 38 is rotated 90 degrees with respect to the bright and dark image in the irradiation light beam 47 as described above, and thus shows a distribution extending in the R direction. When the tilt about the T-axis occurs in the optical disc 6, the position change of the reflected light beam 12 generated by this tilt occurs as a positional deviation in the R direction as in FIG. However, since the low reflectance portions 12a are distributed in the R direction, even if the tilt around the T-axis of the optical disk 6 occurs and the reflected light beam 12 is displaced, the first light receiving chip 31a and the second light receiving chip. The amount of light received by 31b is hardly affected by the low reflectivity portion 12a, and an R inclination signal can be output by differential detection of both light receiving chips 31a and 31b.

  Thus, in addition to the features of the first, second, and third embodiments, the feature of the fourth embodiment is that the reflectance differs between the recorded portion and the unrecorded portion of the optical disc 6, and the R in the irradiated light beam 47 is R. Even when the low reflectance part 47a exists in a part of the direction, the relative tilt in the R direction (around the axis in the T direction) of the optical head 45 and the optical disc 6 can be detected as the R tilt signal.

  In the fifth embodiment, the LED chip 35 may be formed integrally with the semiconductor substrate 30 in the process steps as in the second embodiment. Other configurations, operations, and effects are the same as those of the fourth embodiment.

(Embodiment 6)
In the first to fifth embodiments described above, the tilt sensor 38 mounted on the optical head 45 in which the reflector is the optical disk 6 has been described. The tilt sensor 38 is configured to detect the relative tilt between the optical head 45 and the optical disc 6 in the R direction (around the axis in the T direction) as an R tilt signal. However, the gist of the present invention is not limited to the above-described configuration, but also includes detecting a positional deviation of the optical disc 6. That is, by devising the tilt sensor 38, it is possible to detect a displacement (positional deviation) in the focus direction of the optical disc 6 with respect to a predetermined reference in the optical head 45.

  In the tilt sensor 38 of the first embodiment, the dividing lines 34 of the light receiving chips 31a and 31b are provided in parallel to the T direction (see FIG. 1A). As shown in FIG. Can be provided in parallel. By doing so, a sensor for detecting the positions of the optical head 45 and the optical disk 6 can be obtained.

  That is, when the optical disk 6 is displaced in the focus direction, the center position of the reflected light beam 12 does not change and the diameter changes. Then, since the light receiving amounts of the first light receiving chip 31a and the second light receiving chip 31b change according to the light beam diameter of the reflected light beam 12, the optical disk 6 with respect to the optical head 45 is based on the light receiving amounts of the light receiving chips 31a and 31b. Focus direction displacement (positional deviation) can be derived.

  In the sixth embodiment, the LED chip 35 may be formed integrally with the semiconductor substrate 30 in the process step as in the second embodiment. Other configurations, operations, and effects are the same as those in the first embodiment.

(Embodiment 7)
As shown in FIG. 14, the sensor 38 according to the seventh embodiment of the present invention is configured as a sensor for detecting positional deviation or inclination of an optical component or the like, unlike the tilt sensor of the first to sixth embodiments described above. Is.

  For example, when the objective lens, which is an optical component, is configured to be displaced integrally with its holding member (described later), for example, the light emitted from the LED chip 35 of the position sensor 38 is irradiated to the holding member, and the reflection thereof. If it is placed at a position where light can be received by the light receiving area of the sensor (for example, in the vicinity of the holding member), the inclination or displacement of the holding member can be detected, and thereby the inclination or displacement of the objective lens held by the holding member Can be detected.

  This will be specifically described. As shown in FIG. 14, the optical head 45 includes an optical block 44 and an actuator 43 that is a condensing element driving unit. The actuator 43 includes a fixed portion 51, a holding member 48, and an objective lens 42. The holding member 48 is held on the fixed portion 51 by four wires 50 provided on the fixed portion 51. The objective lens 42 is held by a holding member 48.

  The optical block 44 includes a semiconductor laser 41, a collimating lens 52, a mirror 49, and the like as main components. The light emitted from the semiconductor laser 41 becomes substantially parallel light by the collimator lens 52, is reflected by the mirror 49, enters the objective lens 42 on the holding member 48, and records / reproduces the information signal of the optical disk 6.

  The tilt sensor 38 of the present embodiment is provided with the wiring board 39 interposed in the fixed portion 51 of the actuator 43. The tilt sensor 38 emits outgoing light to the holding member 48 and receives the reflected light with a light receiving chip. Here, if the light receiving chip is divided into two as in the first embodiment, the tilt of the holding member 48 can be detected by the same principle as the tilt detection of the optical disc 6. As a result, since the amount of displacement caused by the weight of the objective lens 42 can be detected from the position detection signal of the objective lens 42, for example, when the attitude of the optical disk drive device changes, the position of the objective lens is corrected within the optical head 45. Thus, stable control over the optical disc 6 can be performed.

  Instead of the configuration in which the light receiving chip of the tilt sensor 38 is divided into two, the light receiving chip is not divided, and the reflection region of the emitted light beam in the holding member 48 is divided into a plurality of regions each having a different reflectance. It can also be set as the structure made. For example, as shown in FIG. 15, the reflective region 67 includes a first reflective portion 67a having a relatively high reflectance and a second reflective portion 67b having a reflectance that is lower than that of the first reflective portion 67a. The tilt sensor 38 is installed at a position where the irradiation light beam 47 formed on the reflection region 67 straddles the first reflection part 67a and the second reflection part 67b. When the holding member 48 is displaced in the vertical direction in FIG. 15, for example, the reflectance of the irradiated light beam 47 in the reflection region 67 differs depending on the positional deviation, and thus the displacement of the holding member 48 can be detected. That is, it is possible to detect a positional shift of the holding member 48 in a direction substantially orthogonal to the emitting direction from the LED chip 35. Even in this case, the inclination of the holding member 48 in the left-right direction can be detected.

  In the seventh embodiment, the LED chip 35 may be formed integrally with the semiconductor substrate 30 in the process steps as in the second embodiment. Other configurations, operations, and effects are the same as those in the first embodiment.

(Embodiment 8)
As shown in FIG. 16, the sensor 38 according to the eighth embodiment of the present invention detects the tilt or misalignment of the collimator lens 52 that is an optical component disposed between the semiconductor laser 41 and the objective lens 42. It is configured as a sensor.

  In the case where the collimating lens 52 that converts the emitted light from the semiconductor laser 41 into parallel light is configured to move in the optical axis direction by the driving means 54 integrally with the holding member 53, the sensor 38 of the eighth embodiment is connected to the LED. The position of the holding member 53 can be detected by irradiating the light emitted from the chip 35 onto the holding member 53 and placing the reflected light at a position where the reflected light can be received by the light receiving region of the sensor 38 (for example, in the vicinity of the holding member). As a result, the position of the collimating lens 52 held by the holding member 53 can be detected.

  This will be specifically described. As shown in FIG. 16, the optical head 45 includes a semiconductor laser 41, a collimating lens 52, a holding member 53, a driving unit 54, a mirror 49, an objective lens 42, and the like as main components. The collimating lens 52 is held by the holding member 53 and is disposed between the semiconductor laser 41 and the mirror 49. The drive unit 54 is configured to drive the holding member 53 in the optical axis direction.

  The tilt sensor 38 is attached to the optical system block 44 with a wiring board 39 interposed. The tilt sensor 38 emits outgoing light to the holding member 53 and receives the reflected light with a light receiving chip. Thereby, it is possible to detect an inclination or a positional deviation of the holding member 53. In this way, it is possible to correct the spherical aberration by controlling the position of the collimating lens 52 in the optical head 45 with respect to the spherical aberration caused by the thickness of the optical disc 6, for example, by the detected position detection signal of the collimating lens 52. Become.

  Furthermore, between the collimating lens 52 and the objective lens 42, at least two lenses (not shown) that receive parallel light from the collimating lens 52 and a holding for holding one of the two lenses. In the case of a configuration further including a member (not shown) and a moving means (not shown) that moves the one lens and the holding member together in the optical axis direction, the sensor described in the present embodiment The position of the holding member can be detected by irradiating the holding member 38 with light from the LED chip 35 and placing the reflected light at a position where the reflected light can be received by the light receiving region of the sensor 38 (for example, in the vicinity of the holding member). Thus, the position of one lens that is an optical component held by the holding member can be detected. With this configuration, it is possible to correct the spherical aberration by controlling the position of one lens within the optical head, for example, for spherical aberration caused by the thickness of the optical disk, from the position detection signal of one lens. It becomes.

  In the first to eighth embodiments described above, the tilt sensor 38 is mounted on the optical head 45 and detects the tilt and displacement of the optical disk 6 as a reflector and the components of the optical head 45. However, the tilt sensor 38 is not limited to the one mounted on the optical head 45, and the reflector is not limited to the optical disk 6 or the components of the optical head 45. Here, the sensor itself which detects the inclination and positional deviation of the reflector with the above-described configuration is based on the gist of the present invention.

  In the first to eighth embodiments described above, the tilt sensor 38 functions as a so-called two-divided photodiode by forming the light receiving chips 31 a and 31 b on the semiconductor substrate 30, but receives light on the semiconductor substrate 30. The sensor provided with a circuit unit for amplifying and calculating the photocurrent from the chips 31a and 31b is also based on the gist of the present invention.

(Embodiment 9)
A configuration of an optical information medium driving device to which the optical head 45 of Embodiment 1 is applied will be described. As shown in FIG. 17, the optical information medium driving apparatus includes an optical head 45, a rotation driving mechanism 71, a detection circuit 72, a reproduction circuit 73, a tracking control circuit 74, a focus control circuit 75, and the like as main components.

  The rotation drive mechanism 71 drives the optical disc 6 to rotate by a motor (not shown). The detection circuit 72 generates a reproduction signal, a tracking error signal, and a focus error signal based on the reflected light branched by the optical head 45. The reproduction circuit 73 reproduces information recorded on the optical disc 6 based on the reproduction signal. The tracking control circuit 74 controls the optical head 45 so as to compensate the tracking error based on the tracking error signal. The focus control circuit 75 controls the optical head 45 so as to compensate for the focus error based on the focus error signal.

  In the present embodiment, the optical head 45 of the first embodiment is applied. However, instead of this, the optical head 45 of any of the second to seventh embodiments may be applied.

(A) It is a top view of the inclination sensor in the optical head by Embodiment 1 of this invention. (B) It is a side view of the inclination sensor in the optical head by Embodiment 1 of this invention. (C) It is a front view of the inclination sensor in the optical head by Embodiment 1 of this invention. (A) It is a top view of the optical head by Embodiment 1 of this invention. (B) It is a side view of the optical head by Embodiment 1 of this invention. (C) It is a front view of the optical head by Embodiment 1 of this invention. (A) It is a figure which shows the relationship between the inclination sensor by Embodiment 1 of this invention, and reflected light flux when there is no relative inclination of a R direction. (B) It is a figure which shows the relationship between the inclination sensor by Embodiment 1 of this invention, and reflected light beam when the relative inclination of + direction of R direction generate | occur | produces. (C) It is a figure which shows the relationship between the inclination sensor by Embodiment 1 of this invention, and reflected light beam when the relative inclination of-direction of R direction generate | occur | produces. It is sectional drawing which shows the structure of the inclination sensor by Embodiment 1 of this invention. (A) It is a top view of the inclination sensor in the optical head by Embodiment 3 of this invention. (B) It is a side view of the inclination sensor in the optical head by Embodiment 3 of this invention. (C) It is a front view of the inclination sensor in the optical head by Embodiment 3 of this invention. (A) It is a top view of the inclination sensor in the optical head by Embodiment 4 of this invention. (B) It is side surface sectional drawing of the inclination sensor in the optical head by Embodiment 4 of this invention. (C) It is front sectional drawing of the inclination sensor in the optical head by Embodiment 4 of this invention. (A) It is a top view which shows the arrangement | positioning state of the cylindrical element by Embodiment 5 of this invention. (B) It is side surface sectional drawing which shows the arrangement | positioning state of the cylindrical element by Embodiment 5 of this invention. (C) It is front sectional drawing which shows the arrangement | positioning state of the cylindrical element by Embodiment 5 of this invention. It is a figure which shows the irradiated light beam formed on the optical disk in the optical head by Embodiment 5 of this invention. (A) It is a figure which shows the reflected light beam irradiated to the inclination sensor in the optical head by Embodiment 5 of this invention. (B) It is side surface sectional drawing of the inclination sensor in the optical head by Embodiment 5 of this invention. (C) It is front sectional drawing of the inclination sensor in the optical head by Embodiment 5 of this invention. It is a figure which shows the locus | trajectory of the light beam of the emitted light beam from an LED chip, and the light beam of the reflected light beam from an optical disk. It is a figure which shows typically the irradiation light beam on the optical disk in Embodiment 5 of this invention. (A) It is a figure which shows the light beam distribution on the sensor in Embodiment 5 of this invention in case the tilt has not arisen in the optical disk. (B) It is a figure which shows the light beam distribution on the sensor in Embodiment 5 of this invention in case the tilt has arisen in the optical disk. (C) It is a figure which shows the light beam distribution on the sensor in Embodiment 5 of this invention in case the tilt has arisen on the optical disk. It is a top view of the sensor which detects the position shift of the optical head by Embodiment 6 of this invention, and an optical disk. It is a side view which shows the structure of the optical head by Embodiment 7 of this invention. It is a figure which shows the irradiation light beam formed in the holding member in Embodiment 7 of this invention. It is a side view which shows the structure of the optical head by Embodiment 8 of this invention. It is the schematic which shows the structure of the optical information medium drive device by Embodiment 9 of this invention. It is a figure which shows the structure of the optical head which performs the conventional optical disk inclination detection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 41: Semiconductor laser 2: Light beam 4: Beam splitter 5, 42: Objective lens 6: Optical disk 7: Aperture limiting means 8: Unnecessary light beam 9, 17: Light spot 10: Light detector 11: Emission light beam 12: Reflected light beam 13: differential circuit 14: photo detectors 14a and 14b for tilt detection 15: detection region 15: subtractor 30: silicon substrate 31a, 31b: light receiving chips 32a, 32b, 33, 36: electrode 34: dividing line 35: LED chip 37: Light emitting point 38: Tilt sensor 39: Wiring substrate 43: Actuator 44: Optical system block 45: Optical head 46: Cylindrical element 47: Irradiation light beam

Claims (9)

An optical head that collects information recording or reproducing light emitted from a laser light source on an optical information medium and receives reflected light from the optical information medium,
Sensor is provided for detecting-out inclination of the optical information medium with respect to a predetermined reference,
The sensor is
A substrate,
A light source chip element provided on the substrate;
A light receiving region provided on the substrate and receiving light emitted from the light source chip element and reflected by the optical information medium;
The light receiving region is divided into a plurality of regions, it is configured to detect-out inclination of the optical information medium by the difference in the amount of received light in each region,
The optical information medium is formed in a disc shape,
A cylindrical element is provided in the optical path between the optical information medium and the light receiving region,
The light receiving region is divided with a dividing line extending in a direction parallel to the tangential direction of the optical information medium as a boundary,
The optical head is characterized in that the cylindrical element is arranged such that a bus line is inclined with respect to the dividing line.   2. The optical head according to claim 1, wherein the cylindrical element is arranged such that a bus line forms an angle of 40 degrees to 50 degrees with respect to the dividing line.   The optical head according to claim 2, wherein the cylindrical element is disposed such that a bus line forms an angle of 45 degrees with respect to the dividing line. A recess is formed on the surface of the substrate,
4. The optical head according to claim 1, wherein the light source chip element is disposed in the concave portion. 5.   The optical head according to claim 4, wherein a side surface of the recess is tapered.   The optical head according to claim 1, wherein the light source chip element is an LED element. The substrate is made of a semiconductor,
The optical head according to claim 1, wherein the light source chip element is formed integrally with the substrate.   8. The optical head according to claim 1, wherein the substrate is provided with a circuit unit that amplifies and calculates a photocurrent from the light receiving region. An optical head according to any one of claims 1 to 8, comprising:
An optical information medium driving apparatus which records information on an optical information medium or reproduces recorded information.

Images