JP2009076123A - Optical pickup device and optical lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device provided with an optical lens driving device capable of not only determining an original position by moving a lens holder but also recognizing whether desired operation is accurately performed even when the lens holder is moved from the original position once and to provide the optical lens driving device. <P>SOLUTION: In the optical pickup device, when whether the lens holder is normally moved is recognized by moving the lens holder in an optical axial direction and detecting a first lighting period, a first light shielding period and a second lighting period by using a photo detector in a photosensor, the first light shielding period is set in a length by which judgment of recognition of operation can be performed by sensing the magnitude corresponding to a linear movement amount of a transmission direction conversion mechanism by the number of preset regular pulses inputted in a stepping motor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup device having an optical lens driving device that has an origin detection function and an operation confirmation function and slides an optical lens in an optical axis direction, and the optical lens driving device.

  2. Description of the Related Art Conventionally, an optical pickup device mounted on an optical disc apparatus that reproduces or records an optical disc such as a DVD irradiates a recording layer of the optical disc with a light beam oscillated from a light source to read or write information. Used as a device. This optical pickup device has a problem in that information reading or writing performance deteriorates due to the influence of wavefront aberration caused by various factors. This wavefront aberration includes coma due to the tilt angle of the optical disc, thickness error of the cover layer of the optical disc, spherical aberration associated with the multilayered information recording surface, and astigmatism due to the optical system. . Among these aberrations, the above-mentioned spherical aberration, in particular, has a greater effect as the recording density of the optical disc increases, and the technology that corrects this spherical aberration is important for realizing higher optical disc densities in the future. It is one of the elements.

  In order to correct this spherical aberration, an optical pickup device having means for canceling the spherical aberration by sliding an optical lens in the optical axis direction is disclosed (for example, see Patent Document 1). This optical pickup device includes a light source, an objective lens that focuses a light beam from the light source on a recording layer of a high-density optical disc, and an optical lens that moves between the light source and the objective lens in the optical axis direction to obtain a spherical surface. An optical lens driving device for canceling out the aberration is provided.

  Further, in this optical lens driving device, the lens holder holding the optical lens and the sliding shaft provided on the support substrate are engaged, and the rotational driving force by the step motor is transmitted to the lens holder by the transmission direction conversion mechanism. And a mechanism for moving the lens holder in the sliding axis direction. Further, the lens holder is provided with a shielding plate. By moving the lens holder, the shielding plate is inserted into and removed from the photosensor arranged on the support substrate, so that the origin position of the lens holder that holds the optical lens. Can be determined. Then, starting from this origin position, the lens holder is moved in the optical axis direction.

  According to such an optical lens driving device, the origin position of the optical lens moved in the optical axis direction by the step motor can be accurately grasped. It is possible to cancel the spherical aberration that has caused the reading or writing error.

JP 2003-131113 A (page 3-4, FIG. 1)

  With the optical lens driving device described in Patent Document 1, the origin of the lens holder can be accurately determined by inserting and removing the shielding plate from the photosensor by moving the lens holder. If the optical lens is moved from this origin position, it cannot be confirmed whether the optical lens is operating normally thereafter. If the position of the lens holder is to be specified in a state where the lens holder is separated from the origin position, it is necessary to detect two or more origin positions. Incorporating these two or more sets of photosensors and shielding plates into the apparatus is not preferable because the mounting area of the apparatus increases.

  The object of the present invention is to solve the above-mentioned problems and not only determine the origin position by moving the lens holder but also confirm whether the desired operation is accurately performed even if the lens holder is once moved from the origin position. An object of the present invention is to provide an optical pickup device and an optical lens driving device provided with an optical lens driving device.

In order to solve the above problems, the optical lens driving device of the present invention adopts the following configuration.
An optical pickup device according to the present invention is arranged in an optical path of an optical system including a laser light source and an objective lens, and the optical lens has an optical lens driving device for correcting an aberration generated in the optical path. A lens holder in which a driving device integrally forms a lens support portion that supports an optical lens, a transmission direction conversion mechanism that converts a rotational driving force into a driving force in an optical axis direction of the optical lens, and a shielding plate; Step motor for generating rotational driving force, sliding shaft engaged with the lens holder, a support substrate for fixedly mounting the sliding shaft and the step motor, and a light emitting element and a light receiving element attached to the support substrate A photo sensor comprising: moving the lens holder in the optical axis direction, and detecting a first lighting period, a first light blocking period, and a second lighting period with a light receiving element; In confirming the operation of whether or not the sensor holder is moving normally, the first light-shielding period corresponds to the linear movement amount of the transmission direction conversion mechanism by the preset prescribed number of pulses input to the step motor. It is characterized by detecting whether the lens holder has moved by the size of the lens holder and setting it to a length that allows determination of operation confirmation.

  In addition, the optical pickup device of the present invention performs the origin detection of the lens position based on the first inflection point of the amount of light collected by the light receiving element between the first daylighting period and the first light shielding period. The operation is confirmed by detecting the amount of linear movement of the transmission direction conversion mechanism with reference to the second inflection point of the amount of light collected by the light receiving element between one light shielding engine and the second daylighting period. To do.

  Further, the optical pickup device provides a second light shielding period after the second daylighting period, and a first variation of the amount of light collected by the light receiving element between the first daylighting period and the first light shielding period. The origin of the lens position is detected using the point as a reference, and a third inflection point of the amount of light collected by the light receiving element between the first inflection point, the second daylighting period, and the second shading period is obtained. As a reference, the amount of linear movement of the transmission direction conversion mechanism is detected and the operation is confirmed.

  In addition, the optical pickup device includes a rotation output gear for transmitting the rotational driving force to the outside, and a rack portion fixedly disposed on the lens holder, in which the transmission direction conversion mechanism described above constitutes a step motor, The rotation output gear and the rack portion are engaged with each other, and the lens holder is moved by the rotational driving force generated by the step motor.

An optical lens driving device according to the present invention is an optical lens driving device that is inserted in an optical pickup device and corrects an aberration that occurs in an optical path of an optical system including a laser light source and an objective lens. A lens, a lens holder that supports the optical lens, a sliding shaft that engages with the lens holder, a step motor that generates a rotational driving force and moves the lens holder, and a rotational driving force that transmits the light of the optical lens A transmission direction conversion mechanism for converting to an axial driving force, a support substrate for fixedly mounting the slide shaft and the step motor, a shielding plate attached to the lens holder or the transmission direction conversion mechanism, and a support substrate And a photosensor comprising a light emitting element and a light receiving element for detecting the position of the shielding plate, and moving the lens holder in the optical axis direction so that the light receiving element has a first lighting period, In detecting the first light-shielding period and the second daylighting period and confirming the operation of whether or not the lens holder is operating normally, the first light-shielding period is set in advance to be input to the step motor. It is characterized by detecting whether the lens holder has moved by the amount corresponding to the linear movement amount of the transmission direction conversion mechanism according to the specified number of pulses, and setting it to a length that allows determination of operation confirmation. .

  An optical pickup device equipped with an optical lens driving device capable of confirming whether or not the device is accurately performing a desired operation even if the optical lens is moved from the origin position together with grasping the origin position of the optical lens; The optical lens driving device can be provided.

  Hereinafter, an optical lens driving device of the present invention and an optical pickup device including the optical lens driving device will be described in detail with reference to the drawings.

  First, the configuration of Example 1 of the optical lens driving device of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing a schematic view of an optical lens driving device of the present invention.

  As shown in FIG. 1, the optical lens driving device 1 according to the first embodiment has not only the origin of the optical lens 3 having the shielding plate 4d and the photosensor 20, but also a preset position. The specified number of pulses is input to the step motor 10 to detect the movement of the lens holder 4 and confirm the operation.

  In FIG. 1, reference numeral 1 denotes an optical lens driving device. Reference numeral 2 denotes a support substrate for disposing and mounting main components of the optical lens driving device 1. A part of the support substrate 2 has a support wall rising at a right angle, and holds two lens holder sliding shafts 32a and 32b. Reference numeral 20 denotes a photosensor including a light emitting element and a light receiving element, which is also fixed to the support substrate 2. The light emitting element and the light receiving element constituting the photosensor 20 are placed facing each other inside the U-shaped groove of the sensor.

  The lens holder 4 includes a lens support portion 4 a that supports the optical lens 3, a slide receiving portion 4 b that is engaged with the lens holder slide shafts 32 a and 32 b, a rack portion 4 c, and a U-shape of the photosensor 20. The shield plate 4d-1 is inserted into and removed from the groove to block light reception by the light receiving element, and is integrally molded. In the drawing, an example in which the shielding plate 4d-1 is fixed to the sliding receiving portion 4b is shown.

  In addition, when the power is input to the optical lens driving device and the shielding plate 4d-1 is moved, the light emitted from the light emitting element of the photosensor 20 and reaching the light receiving element is received by the light receiving element during the first lighting period. Each member is arranged so that the light is light-shielded in the first light-shielding period, and then again in the second light-collecting period. Further, in the light shielding plate 4d-1, it is assumed that the first light shielding period is set to a size corresponding to a linear movement amount by which the lens holder moves by a preset number of predetermined pulses. The effect of the arrangement relationship between the photosensor 20 and the light shielding plate 4d-1 will be described later.

  Reference numeral 10 denotes a step motor that generates a driving force for moving the lens holder in the direction of the optical axis 5, and is fixed to the support substrate 2. Reference numeral 11 denotes a rotation output gear that is rotationally driven by the step motor 10. Here, when the rotation output gear 11 meshes with the rack portion 4c, the rotation motion of the rotation output gear 11 is converted into a linear motion in the A direction and functions as a transmission direction conversion mechanism.

Reference numerals 32 a and 32 b denote two lens holder sliding shafts, which are fixed to the support substrate 2 so as to be parallel to the optical axis 5 of the optical lens 3. The sliding receiving portion 4b which is a part of the lens holder 4 is slidably engaged with the two lens holder sliding shafts 32a and 32b, and the rack portion 4c is moved by the driving force from the rotation output gear 11. The optical lens 3 supported by the integrated lens holder supporting portion 4a is guided by the lens holder sliding shafts 32a and 32b to be engaged and moves in the direction of arrow A along the optical axis 5. .

  Next, the positional relationship between the shielding plate 4d-1 and the photosensor 20 when the lens holder 4 of the optical lens driving device is operated in the direction of the optical axis 5 will be described. FIG. 2 is a top view of the optical lens driving device of the present invention.

  The state shown in FIG. 2A shows a state when the power is turned on and the optical lens 3 hits a positioning member (not shown) and is at the operation start point. In this state, the shielding plate 4d-1 attached to the lens holder 4 is not inserted into the photosensor 20, and the light emitted from the light emitting element of the photosensor 20 reaches the light receiving element without being blocked.

  Then, when the lens holder 4 is moved in the A direction (rightward on the paper surface) from the operation start point by driving the step motor 10, as shown in FIG. 2B, the shielding plate 4d- attached to the lens holder 4 is provided. 1 is inserted into the photosensor 20. At that time, light emitted from the light emitting element of the photosensor 20 and reaching the light receiving element is blocked by the shielding plate 4d-1.

  Next, details of the shielding plate, which is a characteristic part of the optical lens driving device 1 of the present invention, will be described with reference to FIGS. FIG. 3 is a diagram showing the positional relationship between the shielding plate and the photosensor in the optical lens driving device of the present invention. This figure (a)-(g) is the lighting range 30 which a light receiving element receives the light from the light-emitting element in the shielding board 4d-1 and a photosensor when the shielding board 4d-1 moves to an optical axis direction. It is drawing for demonstrating the positional relationship with these. In addition, this drawing is a drawing viewed from the light receiving element side in the U-shaped groove of the photosensor. FIG. 4 is a drawing showing the amount of light collected by the light receiving element in the photosensor 20 in the states of FIGS. 3A to 3G. The vertical axis represents the amount of light collected by the light receiving element, and the horizontal axis represents the shielding plate 4d−. 1 shows a positional relationship with respect to one photosensor. In addition, ag shown to the shielding board position of the horizontal axis of this figure has shown the position of the shielding board of Fig.3 (a)-(g).

  As described with reference to FIG. 2, the rotational driving force generated by the step motor 10 is converted into a linear driving force, and the lens holder 4 moves in the arrow A direction. Accordingly, the shielding plate 4d-1 in the lens holder 4 starts to move from the positional relationship shown in FIG. 3A with respect to the lighting range 30 of the photosensor 20 fixed to the support substrate 2.

  When the shielding plate 4d-1 is in the state of FIG. 3A, the light receiving element of the photosensor 20 collects the light of the light emitting element without being shielded by the shielding plate 4d-1, so in FIG. Becomes 100%.

  Next, as shown in FIG. 3B, when the shielding plate 4d-1 starts to enter the daylighting range 30 (this state is the first inflection point), as shown in FIG. The amount of light collected by the photosensor 20 gradually decreases from the first inflection point (FIG. 3 (c)), and the shielding plate 4d-1 completely covers the daylighting range 30 (FIG. 3 ( d)), the light intensity shown in FIG. 4 is 0%.

  Next, as shown in FIG. 3 (f), when the lens holder 4 is moved, the shielding plate 4d-1 passes through the daylighting range 30, and the amount of collected light gradually increases as shown in FIG. To do.

  Next, when the entire shielding plate 4d-1 is out of the daylighting range 30 (FIG. 3 (f)) (this state is taken as the second inflection point), as shown in FIG. 3 (g) and FIG. The amount of light collected becomes a constant value of 100% again and becomes a stable value.

  In the above description, the change in the amount of light collected when the shielding plate 4d-1 is moved from the state shown in FIG. 3A to the state shown in FIG. 3G has been described. ) To the state shown in FIG. 3A, it is also possible to detect an operation for confirming whether the lens holder is operating normally when the shielding plate 4d-1 is moved.

  Here, how to detect the origin position of the optical lens based on the change in the amount of light extraction shown in FIG. 4 caused by moving the shielding plate 4d-1 shown in FIG. 2 will be described.

  By moving the shielding plate 4d-1 as shown in FIG. 3, the light emitted from the light-emitting element of the photosensor 20 and reaching the light-receiving element is shown in FIG. It can be divided into a light shielding period and a second daylighting period. Here, the daylighting period refers to the time when the light intensity of the light receiving element is equal to or greater than a predetermined ratio, and the light shielding period refers to the time when the light intensity of the light receiving element is equal to or less than a predetermined ratio. . FIG. 4 shows an example in which the predetermined ratio is 50%.

  As shown in FIG. 4, when the ratio of the light intensity of the light receiving element determined for detecting the origin position is set to 50%, first, the light at the first inflection point determined that the reduction of the light intensity has started. The position (shielding plate position: c) where the amount of light is 50% or less is detected using the amount (light amount: 100%) as a reference value, and this point is set as the origin position. Further, a pulse smaller by one pulse than the number of pulses corresponding to a preset linear movement amount (width t1 in FIG. 3A) from this origin position (hereinafter referred to as a prescribed pulse number) is sent to the step motor, The amount of light collected when the lens holder is moved is compared with the amount of light collected when a specified number of pulses are sent.

  First, the amount of light collected when the lens holder is moved by sending a pulse one pulse less than the specified number of pulses to the step motor is 50% or less of the amount of light collected at the second inflection point. It is sent to the step motor to check whether the amount of light collected when the lens holder is moved is 50% or more of the amount of light collected at the first inflection point. In this way, if the result of the confirmation of the origin position and the operation confirmation position is obtained, the lens holder moves the linear movement amount corresponding to the preset prescribed pulse by sending the prescribed pulse to the step motor. Therefore, it is determined that the optical lens driving device is operating accurately.

  In the first embodiment, only 50% of the light intensity at the inflection point is set as a threshold value, and the origin position of the lens holder and the case of confirming the operation of whether the lens holder is operating normally from the origin position are described. The same effect as that of the present invention can also be obtained by making the amount of light used when checking the origin position and the operation other light values and adjusting the light shielding range of the light shielding plate in accordance with the light values.

  Next, another configuration example of the shielding plate in the optical lens driving device 1 of the present invention will be described.

  The difference between the optical lens driving device 1 of the first embodiment and the second embodiment lies in the configuration of the shielding plate, the origin position, and how to check the operation, but the other configurations are the same as those described in the first embodiment. It has become. Further, the operation of the lens holder 4 by the step motor 10 is the same as that shown in FIG. Therefore, in the following description, the relationship between the configuration of the shielding plate and the amount of light collected by the light receiving element at that time will be mainly described, and description of other requirements that are the same as the configuration of the first embodiment will be omitted.

  FIG. 5A shows the configuration of the light shielding plate shown in the first embodiment, and FIG. 5B shows the configuration of the light shielding plate in the second embodiment.

  In contrast to the shielding plate 4d-1 shown in FIG. 5A shown in FIG. 5A, the shielding plate 4d-2 shown in FIG. 5B includes a light shielding portion having a width t1 and a width t2. The regions B1 and B2 surrounded by the broken line having the opening portion have a common configuration, but the right area of the broken line has a different shape.

  Here, since the areas B1 and B2 which are broken line areas have the same shape, the light intensity of the light receiving element when the light shielding plates 4d-1 and 4d-2 are inserted into the U-shaped groove of the photosensor is as follows. As exactly the same behavior as described with reference to FIG. 4, the first lighting period shifts to the first light blocking period, the second lighting period starts, and further shifts to the second light blocking period. The light shielding plates 4d-1, 4d-2 have a size corresponding to the linear movement amount by which the lens holder moves from the first light shielding period to the second daylighting period according to a predetermined number of pulses. Suppose that it is set.

  FIG. 6 is a diagram showing the positional relationship between the shielding plate attached to the lens holder of the optical lens driving device of the present invention and the photo sensor. FIGS. 6 (h) to 6 (k) show the shielding plate 4d-2. Shows the positional relationship between the shielding plate 4d-2 and the daylighting range 30 when is moved. FIG. 7 is a diagram showing the relationship between the position of the shielding plate 4d-2 in the present embodiment with respect to the photosensor lighting range 30 and the light intensity of the photosensor. The horizontal axis indicates the position of the shielding plate. In addition, af of the shielding plate position shown on the horizontal axis in the drawing indicates the position of the shielding plate 4d-2 replaced by the shielding plate 4d-1 shown in FIGS. -K has shown the position of shielding board 4d-2 in Drawing 6 (f)-(k).

  First, the rotational driving force generated by the step motor 10 is converted into a linear driving force, and the lens holder 4 moves in the optical axis direction. Accordingly, the shielding plate 4d-2 starts moving from the position shown in FIG. 3A with respect to the daylighting range 30 of the photosensor 20. The amount of light collected by the light receiving element at this time is 100% of the point a in FIG.

  Subsequently, the shielding plate 4d-2 is moved to the positions of FIGS. 3B to 3F, and as shown in FIG. 7, the amount of light collected is once from 100% to the first inflection point, 80%. After that, after passing through 80% again, it goes over the second inflection point and becomes 100%. Therefore, up to this point, the amount of light is the same as that from the first inflection point to the third inflection point shown in FIG.

  Then, if the shielding plate 4d-2 is moved as it is, the shielding plate 4d-2 starts to enter the lighting range 30 again after the second lighting period (FIG. 6 (h)). This state is the third inflection point. Even at the third inflection point, the amount of light collected by the light receiving element is 100% as in the second inflection point.

  Subsequently, when the lens holder is moved, the daylighting range 30 and the shielding plate 4d-2 overlap (FIG. 6 (i)), and the amount of light collected by the photosensor gradually decreases as shown in FIG. go.

  Next, the light shielding plate 4d-2 completely covers the daylighting range 30 (FIG. 6 (j) to FIG. 6 (k)), and as shown in FIG. 7, the light shielding amount of the light receiving element becomes 0%.

  Here, how to detect the origin position of the lens holder provided with the optical lens based on the fluctuation of the amount of light obtained by moving the shielding plate 4d-2 shown in FIG. 7 will be described.

As shown in FIG. 7, when the ratio of the light intensity of the light receiving element determined to detect the origin position is set to 80%, first, the first inflection point (lighting) determined that the decrease of the light intensity has started. The position (shielding plate position: c position) at which the light intensity is 80% is detected with reference to (amount: 100%), and this point is set as the origin. Next, with this origin position as a reference, the lens holder was moved by sending a pulse one pulse less than the prescribed pulse corresponding to a preset linear movement amount (width: t1 in FIG. 5B) to the step motor. However, it is confirmed whether the amount of light collected at (shielding plate position: i position) is 80% or less of the amount of light collected at the third inflection point. If the light intensity is 80% or less, one pulse is further sent to the step motor, and it is confirmed whether the light intensity here is 80% or more with reference to the light intensity at the third inflection point.

  In this way, if the result of the confirmation of the origin position and the confirmation of the operation confirmation position is obtained, the lens holder can set the linear movement amount corresponding to the preset prescribed pulse by sending the prescribed pulse to the step motor. The optical lens driving apparatus determines that it has moved, and determines that it is operating correctly.

  In the second embodiment, an example in which the amount of light collected by the light receiving element is set to 80% has been described. However, the same effect can be obtained regardless of the ratio as long as the ratio is greater than 0% and less than 100%. Can be obtained. That is, if the configuration of the shielding plate 4d-2 in the present embodiment shown in FIG. 5B and the detection method are used, the light intensity profile shown in FIG. 7 is always inclined from the shielding plate position b to d. This is because the inclination from the shielding plate position i to j is always constant.

  Further, in the second lighting period, when the shielding plate is not covered at all in the daylighting range 30, the amount of light collected at the first inflection point and the second inflection point is both equal to 100%. Only in this case, by configuring the shielding plate 4d-2 as in the second embodiment, disturbance or the like can be obtained without storing or calculating the amount of light collected at the inflection point only by providing a certain threshold value. Even if there is, it is possible to always confirm the operation of the lens holder accurately.

  Next, a schematic diagram of the overall configuration of the optical pickup device of the present invention will be described based on the block diagram of FIG. FIG. 8 is a block diagram showing a configuration example of an optical pickup device 50 equipped with the optical lens driving device of the present invention.

  In FIG. 8, reference numeral 50 denotes an optical pickup device according to the present invention, in which an optical lens driving device 1 includes an optical system including laser light sources 41a to 41c for oscillating light beams of three different wavelengths and an objective lens 46. The structure is incorporated in the optical path.

  Here, for example, the laser light source 41a emits a light beam 42a that is a laser beam having a wavelength λ = 405 nm, and corresponds to a high-density optical disc such as a Blu-ray disc. For example, the laser light source 41b emits a light beam 42b which is a laser beam having a wavelength λ = 785 nm, and corresponds to an optical disk such as a CD. The laser light source 41c emits, for example, a light beam 42c that is laser light having a wavelength λ = 660 nm, and corresponds to an optical disc such as a DVD.

  Reference numerals 43a and 43b denote prisms which are arranged on the optical path of the light beam 42a. The prism 43a changes the optical path by 90 degrees by the incidence of the light beam 42b from the laser light source 41b. Also, the prism 43b changes the optical path by 90 degrees by entering the light beam 42c from the laser light source 41c. Thereby, the optical paths of the light beams 42b and 42c coincide with the optical path of the light beam 42a. Reference numeral 44 denotes a deflecting beam splitter (hereinafter abbreviated as PBS) which passes through the light beams 42a, 42b and 42c and changes the optical path of reflected light 42d described later by 90 degrees.

  Reference numeral 45 denotes a λ / 4 retardation plate and reference numeral 46 denotes an objective lens, both of which are arranged in the optical path of the light beams 42a to 42c. The optical lens driving device 1 according to the present invention is provided in the optical path of the optical system including the three laser light sources 41a, 41b, 41c and the objective lens 46, and corrects spherical aberration. In other words, the optical lens 3 of the optical lens driving device 1 is placed in the optical path of the light beams 42a to 42c, and the motor drive signal M1 from the drive IC 62 is supplied to the step motor 10, and the step motor 10 has a sliding mechanism. The optical lens 3 is moved via

  The liquid crystal element 71 is disposed between the optical lens driving device 1 and the λ / 4 retardation plate 45, and a liquid crystal driving signal O1 from the driving IC 62 is supplied to the liquid crystal element 71 to correct aberrations. The drive IC 62 inputs a control signal C1 from the outside and executes control of the step motor 10, the photo sensor 20, and the liquid crystal element 71.

  Reference numeral 47 denotes an optical disk capable of reproducing or recording information, and the light beams 42a to 42c collected by the objective lens 46 are irradiated to reflect the reflected light 42d. A condensing lens 48 is disposed in the optical path of the reflected light 42 d whose optical path is changed by 90 degrees by the PBS 44. Reference numeral 49 denotes a photodetector which receives the reflected light 42d from the condenser lens 48 and converts it into an electrical signal.

Next, the operation of the optical pickup device 60 of the present invention will be described based on FIG.
In addition, the overlapping description related to the optical lens driving device 1 of the present invention mounted on the optical pickup device 60 is partially omitted. Further, as a premise of the description, description will be made assuming that a high-density optical disc such as a Blu-ray disc is reproduced.

  In FIG. 8, when a 405 nm light beam 42a is emitted from the laser light source 41a, the light beam 42a passes through the two prisms 43a and 43b and the PBS 44, and further passes through the optical lens 3 and the liquid crystal element 71 of the optical lens driving device 1. pass.

  The light beam 42a is converted into circularly polarized light by the λ / 4 phase difference plate 45, passes through the objective lens 46, is condensed by the objective lens 46, and information on the high-density optical disc 47 such as a Bull-ray disc. Irradiates the recording surface. The light beam 42 a applied to the optical disc 47 is reflected by the information recording surface of the optical disc 47 to become reflected light 42 d and passes through the objective lens 46 and the λ / 4 retardation plate 45 again. The reflected light 42 d that has passed through the λ / 4 retardation plate 45 passes through the liquid crystal element 71 and the optical lens 3 of the optical lens driving device 1 again and enters the PBS 44.

  The reflected light 42 d that has entered the PBS 44 is focused on the photodetector 49 by the condenser lens 48 with the optical path changed by 90 degrees in the PBS 44. The light detector 49 converts the intensity of the reflected light 42 d into an electric signal, and sends a light detection signal to an external controller (not shown) to reproduce information recorded on the optical disk 47. In addition, the controller that inputs the light detection signal outputs a control signal C1 to the drive IC 62 to correct the aberration of the light beam 42a and the reflected light 42d, and the step motor 10 of the optical lens driving device 1 and the liquid crystal element 71 to correct the aberration generated in the optical path by respectively controlling 71 and to obtain appropriate reflected light 42d.

  Here, the optical lens driving device 1 drives the step motor 10 by the motor driving signal M1 from the driving IC 62, obtains the output of the photosensor 20 by the output signal F1, and follows the first or second embodiment. Then, the origin position of the optical lens 3 is detected and the operation of the optical lens 3 is confirmed to be normally performed. The optical lens 3 is moved in the direction of arrow A by a sliding mechanism, and changes the positional relationship with the objective lens 46, thereby correcting spherical aberration due to a thickness error of the cover layer of the optical disc 47 and the like. In particular, in the reproduction / recording of a high-density optical disc such as a Blu-ray disc, the spherical aberration correction is important because this spherical aberration greatly affects the performance.

  Further, by providing the liquid crystal element 71 between the optical lens driving device 1 and the λ / 4 phase difference plate 45, correction of spherical aberration, coma aberration caused by the tilt angle of the optical disk 47, and the like are caused by the optical system. To correct astigmatism.

As described above, by incorporating the optical lens driving device 1 shown in Embodiments 1 and 2 into the optical pickup device 50 of the present invention, it functions together with the liquid crystal element 71 to collectively correct a plurality of aberrations of the light beam. In particular, it is suitable for reproduction / recording of high-density optical discs such as Blu-ray discs and multilayer recording optical discs.

  The light beams 42b and 42c emitted from the laser light source 41b corresponding to an optical disk such as a CD and the laser light source 41c corresponding to an optical disk such as a DVD are prisms 43a and 43b on the respective optical paths, and the optical path is 90. The subsequent optical path passes through the same optical path as the light beam 42a, and the operation is basically the same.

  As described above, the optical pickup device 50 of the present invention can correct spherical aberration by the optical lens driving device 1 and can correct coma and astigmatism by the liquid crystal element 71. Thus, the optical pickup device 50 is suitable for recording / reproducing of a high-density optical disk that requires a correct aberration correction.

  In the above description, the configuration example in which the driving IC 62 that inputs the control signal C1 from the outside and controls the step motor 10, the photosensor 20, and the liquid crystal element 71 is provided inside the optical lens driving device 1 is shown. This may be provided separately from the optical lens driving device.

  Next, based on FIG. 9, the outline of the whole structure of the optical pick-up apparatus of this invention is demonstrated. FIG. 9 is a block diagram showing another configuration example of an optical pickup device equipped with the optical lens driving device of the present invention.

  Here, the feature of the optical pickup device 60 of the present embodiment is that the optical lens driving device 1 to be mounted has two optical lenses for correcting spherical aberration. In addition, the same number is attached | subjected to the same element as Example 3, and the overlapping description is abbreviate | omitted.

  In FIG. 9, reference numeral 60 denotes an optical pickup device of the present invention, in which the optical lens driving device 1 is incorporated. The optical lens driving device 1 is basically the same as the optical lens driving device 1 shown in the first and second embodiments, but has two optical lenses, one of which is moved by a step motor. The point is different.

  Here, a laser light source 41 a is provided inside the optical pickup device 60. The laser light source 41a emits a light beam 42a that is laser light having a wavelength λ = 405 nm, for example, and corresponds to a high-density optical disc such as a Blu-ray disc.

  A collimator lens 51, a PBS 44, a liquid crystal element 71, a λ / 4 phase difference plate 45, and an objective lens 46 are disposed on the optical path of the light beam 42a. The optical lens driving device 1 is placed between the PBS 44 and the λ / 4 phase difference plate 45, and the concave lens 81 and the convex lens 82 as the two optical lenses of the optical lens driving device 1 are light beams 42a. Located on the road.

  Similarly to the third embodiment, the driving IC 62 that controls the optical lens driving device 1 inputs the control signal C1, outputs the liquid crystal driving signal O1, drives the liquid crystal element 71, and outputs the motor driving signal M1. The step motor 10 is output and the output signal F1 of the photosensor 20 is obtained to detect the origin, and the concave lens 81 is moved in the direction of arrow A. Other configurations are the same as those of the third embodiment, and thus the description thereof is omitted. In the fourth embodiment, the laser light sources 41b and 41c, which are constituent elements of the third embodiment, are omitted.

  Next, the operation of the optical pickup device 60 of the present invention will be described with reference to FIG. Note that, as a premise of the description, a case where a high-density optical disk such as a Blu-ray disk is reproduced will be described.

  In FIG. 9, when a 405 nm light beam 42a is emitted from the laser light source 41a, the light beam 42a passes through the collimator lens 51 and the PBS 44, and further, the concave lens 81 and the convex lens 82 of the optical lens driving device 1 and the liquid crystal element 71. Pass through.

  Then, the light beam 42a emitted from the liquid crystal element 71 is converted into circularly polarized light by the λ / 4 phase difference plate 45, passes through the objective lens 46, is condensed by the objective lens 46, and is high in a Blu-ray disc or the like. The information recording surface of the density optical disk 47 is irradiated. The light beam 42 a applied to the optical disc 47 is reflected by the information recording surface of the optical disc 47 to become reflected light 42 d and passes through the objective lens 46 and the λ / 4 phase difference plate 45 again. The reflected light 42 d that has passed through the λ / 4 retardation plate 45 passes through the liquid crystal element 71, the convex lens 82 and the concave lens 81 of the optical lens driving device 1 again, and enters the PBS 44.

  Then, the reflected light 42 d incident on the PBS 44 is condensed on the photodetector 49 by the condenser lens 48 after the optical path is changed by 90 degrees in the PBS 44. The photodetector 49 converts the intensity of the reflected light 42 d into an electric signal, and sends the light detection signal to an external controller (not shown) to reproduce the information recorded on the optical disc 47. The controller that receives the light detection signal outputs a control signal C1 to the optical lens driving device 1 to correct the aberration of the light beam 42a and the reflected light 42d, and controls the step motor 10 and the liquid crystal element 71. Aberrations are corrected to obtain the optimum reflected light 42d.

  As described above, the optical pickup device 60 according to the fourth embodiment includes the optical lens driving device 1 and corrects the spherical aberration of the light beam by moving the concave lens 81 of the two optical lenses. In addition, since the optical pickup device 60 of the present embodiment performs spherical aberration correction with two optical lenses, it can perform spherical aberration with high accuracy. The optical lens moved by the optical lens driving device 1 may be a convex lens 82, or both a concave lens 81 and a convex lens 82.

  As described above, the optical pickup device 60 according to the fourth embodiment of the present invention has the same function as the optical pickup device 50 according to the third embodiment, and is suitable for recording / reproducing of a high-density optical disc. The perspective view and block diagram shown in the embodiments of the present invention are not limited to this configuration, and any configuration may be used as long as it satisfies the gist of the present invention.

It is a perspective view which shows the outline of the optical lens drive device of this invention. It is the figure which looked at the optical lens drive device of this invention from the top. It is the figure which showed the relationship between the shielding board of the optical lens drive device of this invention, and a photo sensor. It is the figure which showed the relationship between the position of the shielding board of the optical lens drive device of this invention, and the amount of light extraction. It is a figure which shows the structure of the shielding board of the optical lens drive device of this invention. It is the figure which showed the relationship between the shielding board of the optical lens drive device of this invention, and a photo sensor. It is the figure which showed the relationship between the position of the shielding board of the optical lens drive device of this invention, and the amount of light extraction. It is a block diagram which shows the structure of the optical pick-up apparatus carrying the optical lens drive device of this invention. It is a block diagram which shows the structure of the optical pick-up apparatus carrying the optical lens drive device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical lens drive device 2 Support substrate 3 Optical lens 4 Lens holder 4a Lens support part 4b Sliding receiving part 4c Rack part 4d-1, 4d-2 Shielding board 5 Optical axis 10 Step motor 11 Rotation output gear 20 Photo sensor 30 Daylighting Range 32a, 32b Lens holder sliding shaft 41a, 41b, 41c Laser light source 42a, 42b, 42c Light beam 42d Reflected light 43a, 43b Prism 44 Deflection beam splitter (PBS)
45 λ / 4 retardation plate 46 Objective lens 47 Optical disk 48 Condensing lens 49 Photo detector 50, 60 Optical pickup device 62 Drive IC
71 Liquid crystal element 81 Concave lens 82 Convex lens

Claims (5)

In an optical pickup device that is arranged in an optical path of an optical system including a laser light source and an objective lens and has an optical lens driving device for correcting an aberration occurring in the optical path,
The optical lens driving device includes:
A lens holder integrally formed with a lens support portion that supports the optical lens, a transmission direction conversion mechanism that converts the rotational driving force into a driving force in the optical axis direction of the optical lens, and a shielding plate;
A step motor for generating a rotational driving force;
A sliding shaft engaged with the lens holder;
A support substrate for fixedly mounting the sliding shaft and the step motor;
A photosensor comprising a light emitting element and a light receiving element attached to the support substrate;
The lens holder is moved in the optical axis direction, and the light receiving element detects a first lighting period, a first light shielding period, and a second lighting period, and whether or not the lens holder is moving normally. When checking the operation,
In the first light shielding period, it is detected whether the lens holder has moved by an amount corresponding to the amount of linear movement of the transmission direction conversion mechanism, based on a preset number of predetermined pulses input to the step motor. An optical pickup device characterized in that it is set to a length that allows judgment of operation confirmation. The origin detection of the lens position is performed with reference to a first inflection point of the amount of light collected by the light receiving element between the first daylighting period and the first light shielding period,
The amount of linear movement of the transmission direction conversion mechanism is detected with reference to a second inflection point of the amount of light collected by the light receiving element between the first light shielding period and the second daylighting period. The optical pickup device according to claim 1, wherein an operation check is performed. A second light shielding period is provided after the second daylighting period,
The origin detection of the lens position is performed with reference to a first inflection point of the amount of light collected by the light receiving element between the first daylighting period and the first light shielding period,
The transmission direction changing mechanism based on the first inflection point and a third inflection point of the amount of light collected by the light receiving element between the second daylighting period and the second light shielding period. The optical pickup device according to claim 1, wherein the operation check is performed by detecting the linear movement amount. The transmission direction conversion mechanism includes a rotation output gear for transmitting the rotational driving force to the outside, which constitutes the step motor, and a rack portion fixedly disposed on the lens holder,
4. The light according to claim 1, wherein the rotation output gear and the rack portion are engaged with each other, and the lens holder is moved by the rotation driving force generated by the step motor. 5. Pickup device. An optical lens driving device for correcting an aberration generated in an optical path of an optical system including a laser light source and an objective lens, inserted in an optical pickup device,
An optical lens,
A lens holder for supporting the optical lens;
A sliding shaft engaged with the lens holder;
A step motor for generating a rotational driving force to move the lens holder;
A transmission direction conversion mechanism that converts the rotational driving force into a driving force in the optical axis direction of the optical lens;
A support substrate for fixedly mounting the sliding shaft and the step motor;
A shielding plate attached to the lens holder or the transmission direction changing mechanism;
A photosensor comprising a light-emitting element and a light-receiving element that is attached to the support substrate and detects the position of the shielding plate;
The lens holder is moved in the direction of the optical axis, and the light receiving element detects a first lighting period, a first light shielding period, and a second lighting period, and whether the lens holder is moving normally. When checking the operation,
In the first light-shielding period, it is detected whether the lens holder has moved by an amount corresponding to the amount of linear movement of the transmission direction conversion mechanism, based on a preset number of predetermined pulses input to the step motor. An optical lens driving device characterized in that it is set to a length that allows judgment of operation confirmation.

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