A hologram 48 as optical path branching element has two hologram areas 48b and 48c for diffracting a return light beam into different directions, and a boundary 48a between them is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc 11. The light diffracted by the one hologram area 48b is received by light-receiving sections A1 and A2 of a photodetector IC 44, and the light diffracted by the other hologram area 48c is received by light-receiving sections A3 and A4. With the above-described structure, a position deviation of an objective lens 27 at the time of access to a desired recording track on an optical disc 11 can be detected by finding the difference between the light quantity of the light received by the light-receiving sections A1 and A2 of the photodetector IC 44 and the light quantity of the light received by the light-receiving sections A3 and A4.

This invention relates to an integrated optical element used for an optical pickup for recording and/or reproduction of signals by irradiating with a light beam a signal recording surface of an optical type disc (hereinafter referred to as optical disc) such as a mini disc (MD), a magneto-optical disc (MO), a compact disc (CD) or a CD-ROM, an optical pickup using this integrated optical element, and an optical disc device having this optical pickup.
Conventionally, an optical pickup constituted, for example, as shown in FIG. 1 is proposed as an optical pickup for an optical disc. The optical pickup 1 shown in FIG. 1 has a semiconductor laser element 2 as a light source, an optical member 3 made of a transparent material such as glass or plastics, an objective lens 4 for converging a light, and a photodetector 5 for receiving a light and converting the light to an electric signal.
Of these elements constituting the optical pickup 1, the light-emitting element 2, the optical member 3 and the photodetector 5 are integrated as an integrated element, which is provided in the state of being fixed to a base, not shown. The objective lens 4 is provided on the base via a biaxial actuator, not shown. As the biaxial actuator is driven, the objective lens 4 is minutely moved in biaxial directions, that is, in the direction of radius of an optical disc D and in the direction toward and away from the optical disc D.
In this optical pickup, as the base is fed in the direction of radius of the optical disc D by the driving of a thread feed motor, not shown, a desired recording track on the optical disc can be accessed.
In this optical pickup 1, the optical member 3 has two surfaces in parallel to each other. These two surfaces are arranged to be substantially perpendicular to the optical axis of the light beam from the semiconductor laser element 2. On a first surface (lower-center side in FIG. 1) of the optical member 3 on the side of the semiconductor laser element 2, a grating 3a for diffracting a light beam directed toward the optical disc D into the direction corresponding to the direction along the recording track on the optical disc D and for splitting the light beam into a plurality of beams including at least a main beam and two side beams is formed on the optical axis of the light beam from the semiconductor laser element 2.
Also, on a second surface (upper-center surface in FIG. 1) of the optical member 3 on the side of the optical disc D, a hologram 3b for diffracting a return light beam reflected from the signal recording surface of the optical disc D and for guiding the return light beam to the photodetector 5 is formed on the optical axis of the light beam from the semiconductor laser element 2.
The hologram 3b functions as optical path branching means for branching the optical path of the return light beam directed toward the photodetector 5 from the optical path of the light beam directed toward the optical disc D, by diffracting the return light beam from the optical disc D incident on the second surface of the optical member 3 and thus directing the return light beam toward the photodetector 5.
The hologram 3b has two hologram areas 3b-1 and 3b-2 for diffracting the incident return light beam by different diffraction angles, respectively, as shown in FIG. 1. The boundary between these hologram areas 3b-1 and 3b-2 is formed on the second surface of the optical member 3 so as to be substantially coincident with the direction corresponding to the direction of radius of the optical disc D. The return light beam from the optical disc D becomes incident on the hologram 3b with its center located on the boundary between the two hologram areas 3b-1 and 3b-2, and is bisected along the boundary. The bisected portions are diffracted by different diffraction angles, respectively.
That is, the hologram 3b also functions as return light beam splitting means for bisecting the incident return light beam along a splitting line in the direction corresponding to the direction of radius of the optical disc D.
The photodetector 5 has a center light-receiving section 5a for receiving a return light of the main beam, from among the plurality of beams generated by the grating 3a, and light-receiving sections e and f for receiving return lights of the side beams, provided on both sides of the center light-receiving section 5a, specifically, on both sides of the direction corresponding to the direction along the recording track on the optical disc D, as shown in FIG. 1. The center light-receiving section 5a further has four light-receiving sections a, b, c and d which are divided by a division line d1 in the direction corresponding to the direction of radius of the optical disc D and a division line d2 in the direction along the recording track on the optical disc D.
The division line d1 on the center light-receiving section 5a extends in the direction corresponding to the direction of radius of the optical disc D along the direction of diffraction of the hologram 3b in order to prevent generation of any deviation of the focusing error signal level of a light spot in a focused state due to a change in the oscillation wavelength of the semiconductor laser element 2 or due to a change in the refractive index of the optical member 3 by a temperature change.
In this optical pickup 1, the light beam emitted from the semiconductor laser element 2 becomes incident on the optical member 3 from its first surface, then is split into a plurality of beams by the grating 3a, and then passes through the optical member 3. The optical beam which has passed through the optical member 3 is converged by the objective lens 4 and is cast as a fine light spot onto the signal recording surface of the optical disc D. In this case, three light spots are formed on the signal recording surface of the optical disc D by the main beam and two side beams generated by the grating 3a. In FIG. 1, only the main beam is shown.
The light beams cast on the signal recording surface of the optical disc D reflected by the signal recording surface of the optical disc D so as to be return light beams. The return light beams pass again through the objective lens 4 and become incident on the optical member 3 from its second surface. The return light beams incident on the optical member 3 are diffracted by the hologram 3b formed on the second surface of the optical member 3. Specifically, the return light beams become incident on the hologram 3b with their centers located on the boundary between the two hologram areas 3b-1 and 3b-2, and the portions incident on the individual hologram areas 3b-1 and 3b-2 are diffracted by different diffraction angles, respectively. The return light beams diffracted by the hologram areas 3b-1 and 3b-2 of the hologram 3b pass through the optical member 3 so as to be directed toward the photodetector.
Of the return light beams directed toward the photodetector 5, the return light beam which is a return light of the main beam and is diffracted by the one hologram area 3b-1 of the hologram 3b becomes incident on the two light receiving sections a and b of the center light-receiving section 5a of the photodetector 5. Of the return light beams directed toward the photodetector 5, the return light beam which is a return light of the main beam and is diffracted by the other hologram area 3b-2 of the hologram 3b becomes incident on the remaining two light receiving sections c and d of the center light-receiving section 5a of the photodetector 5. Of the return light beams directed toward the photodetector 5, the return light beams of the side beams become incident on the light-receiving sections e and f of the photodetector 5.
The photodetector 5 converts the lights incident on the light-receiving sections a, b, c, d, e and f to electric signals, and supplies the resultant signals to a signal processing circuit, not shown. The detection signals from the photodetector 5 are amplified by head amplifiers in the signal processing circuit so as to be output signals Sa, Sb, Sc, Sd, Se and Sf, and predetermined arithmetic processing is performed thereon by an arithmetic circuit. Thus, a reproduction signal RF0 is generated. Also, a focusing error signal FE0 is generated by a so-called Foucault method and a tracking error signal TR0 is generated by a three-beam method.
The reproduction signal RF0 is calculated, for example, by the arithmetic circuit carrying out arithmetic processing with the following equation (1).
RF0=(Sa+Sb)+(Sc+Sd)xe2x80x83xe2x80x83(1)
The focusing error signal FE0 is calculated, for example, by the arithmetic circuit carrying out arithmetic processing with the following equation (2), (3) or (4).
FE0=Saxe2x88x92Sbxe2x80x83xe2x80x83(2)
FE0=Scxe2x88x92Sdxe2x80x83xe2x80x83(3)
FE0=(Sa+Sd)xe2x88x92(Sc+Sb)xe2x80x83xe2x80x83(4)
The tracking error signal TR0 is calculated, for example, by the arithmetic circuit carrying out arithmetic processing with the following equation (5).
TR0=Sexe2x88x92Sfxe2x80x83xe2x80x83(5)
On the basis of the focusing error signal FE0 thus generated, the optical pickup 1 carries out focusing servo for driving the biaxial actuator to minutely move the objective lens 4 in the direction toward and away from the optical disc D and thus controls the focal point of the light beam converged by the objective lens 4 so as to be constantly located on the signal recording surface of the optical disc D.
In addition, on the basis of the tracking error signal TR0 generated in the above-described manner, the optical pickup 1 carries out tracking servo for driving the biaxial actuator to minutely move the objective lens 4 in the direction of radius of the optical disc D and thus causes the spot of the light beam converged by the objective lens 4 to follow the recording track on the optical disc D.
By thus carrying out focusing servo and tracking servo while recording/reproducing signals to/from the optical disc D, the optical pickup 1 can carry out appropriate signal recording/reproduction even in the case where the optical disc D is fluctuated or tilted.
Meanwhile, in the case where signal recording/reproduction is to be carried out with the optical disc D in the optical pickup 1, the base must be first fed in the direction of radius of the optical disc to access a predetermined recording track, as described above, in the state where tracking servo is off.
The objective lens 4 is provided movably on the base via the biaxial actuator as described above. Therefore, when the base is fed in the direction of radius of the optical disc D or when the feed operation is stopped, the position of the objective lens with respect to the base is deviated in the direction of radius of the optical disc D (to the inner side or outer side of the optical disc D) from the normal position because of inertia, as shown in FIG. 2.
The deviation of the objective lens 4 from the normal position is eliminated with the lapse of a predetermined time period. However, during this time period for recovering the position of the objective lens 4, recording/reproduction of signals to/from the optical disc cannot be carried out. This is one element that substantially disturbs the high-speed access property of the optical pickup 1.
To realize the high-speed property of such optical pickup 1, the position of the objective lens 4 may be instantaneously recovered by detecting the deviation of the objective lens 4 from the normal position, then feeding the detected deviation back to the biaxial actuator, and controlling the driving of the biaxial actuator to eliminate the deviation of the objective lens 4.
To detect the deviation of the objective lens 4 from the normal position, there is considered, for example, a technique of attaching a position sensor to the objective lens 4 so as to detect the actual position of the objective lens 4 by the position sensor and thus detecting the position deviation of the objective lens 4 from the actual position of the objective lens 4 and the quantity of feeding of the base.
However, this technique requires the position sensor for detecting the position of the objective lens 4 to be separately provided in the optical pickup 1, and therefore causes problems such as the increase in the number of components, increase in size of the optical pickup 1 and rise in cost.
In view of the foregoing status of the art, it is an object of the present invention to provide an optical pickup which realizes the high-speed access property by appropriately and simply detecting the position deviation of the objective lens as the light beam converging means at the time of access without adding any new component, an integrated optical element used therefor, and an optical disc device having this optical pickup.
An integrated optical element according to the present invention, used for an optical pickup for carrying out recording and/or reproduction of signals by irradiating a signal recording surface of an optical disc with a light beam, includes: a light source for emitting the light beam; a photodetector having a light-receiving section for receiving a return light beam reflected by the signal recording surface of the optical disc; a package member for housing the light source and the photodetector therein; an optical member arranged on the package member for transmitting the light beam emitted from the light source and for transmitting the return light beam directed toward the photodetector; and optical path branching means integrally formed with the optical member for separating the optical path of the light beam emitted from the light source and the optical path of the return light beam directed toward the photodetector.
In this integrated optical element, the optical path branching means has at least two diffraction areas for diffracting the return light beam reflected by the signal recording surface of the optical disc, into different directions, respectively, and the boundary between the diffraction areas is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. At least one light-receiving section of the photodetector is divided into a portion for receiving a return light beam diffracted by one diffraction area of the optical path branching means and a portion for receiving a return light beam diffracted by the other diffraction area.
In the integrated optical element according to the present invention, the light source is housed inside the package member and emits the light beam for irradiating the signal recording surface of the optical disc. The light beam emitted from the light source is transmitted through the optical member provided on the package member. Then, the light beam transmitted through the optical member is converged by light beam converging means of the optical pickup and then cast onto the signal recording surface of the optical disc.
The light beam cast on the signal recording surface of the optical disc is reflected by the signal recording surface of the optical disc and thus becomes a return light beam including a signal component. The return light beam passes again through the light beam converging means and then becomes incident on the optical member.
The return light beam incident on the optical member has its optical path separated from the optical path of the light beam emitted from the light source, by the optical path branching means formed integrally with the optical member. Specifically, the optical path branching means includes, for example, a hologram formed on the surface of the optical member. As the return light beam is diffracted by the hologram into the direction toward the photodetector, the optical path of the return light beam is separated from the optical path of the light beam emitted from the light source.
Since the optical path branching means has at least two diffraction areas for diffracting the return light beam in different directions, the return light beams incident on the respective diffraction areas of the optical path branching means are diffracted into different directions by the diffraction areas of the optical path branching means, then transmitted through the optical member, and directed toward the photodetector housed in the package member.
Since at least one light receiving section of the photodetector is divided into the portion for receiving the return light beam diffracted by one diffraction area of the optical path branching means and the portion for receiving the return light beam diffracted by the other diffraction area, the return light beams diffracted into different directions by the respective diffraction areas of the optical path branching means are received by the corresponding portions of the light-receiving section of the photodetector.
Thus, on the basis of the detection signal from the light-receiving section of the photodetector, a reproduction signal is generated and a focusing error signal is generated by a so-called Foucault method.
Meanwhile, in the case where the position of the light beam converging means with respect to the integrated optical element is deviated in the direction of radius of the optical disc from the normal position at the time of access to a desired recording track on the optical disc, the spot of the return light beam incident on the optical member is deviated in the direction corresponding to the direction of radius of the optical disc, on the optical path branching means.
In the integrated optical element according to the present invention, the optical path branching means has at least two diffraction areas for diffracting the return light beam into different directions, and the boundary between these diffraction areas is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. Therefore, in the case where the position of the light beam converging means is deviated in the direction of radius of the optical disc from the normal position, the return light beam is split asymmetrically by the optical path branching means. The individual parts of the return light beam generated by asymmetrical splitting by the optical path branching means are received by the corresponding portions of the light-receiving section of the photodetector. Therefore, the position deviation of the light beam converging means with respect to the integrated optical element can be detected on the basis of the detection signal from the light-receiving section of the photodetector.
According to the integrated optical element of the present invention, since the position deviation of the light beam converging means with respect to the integrated optical element at the time of access to a desired recording track on the optical disc can be detected in the above-described manner, the optical pickup using this integrated optical element can realize the high-speed access property.
Also, in this integrated optical element, the optical path branching means for separating the optical path of the return light beam directed toward the photodetector from the optical path of the light beam emitted from the light source and for generating a focusing error signal by the Foucault method is used for detecting the position deviation of the light beam converging means with respect to the integrated optical element, instead of additionally providing any means for detecting the position deviation of the light beam converging means. Therefore, the optical pickup using this integrated optical element can realize the high-speed access property by appropriately and simply detecting the position deviation of the light beam converging means, without causing the increase in the number of components, the increase in the size of the device itself and the rise in cost.
In the integrated optical element according to the present invention, it is desired that light beam splitting means for diffracting the light beam directed toward the optical disc and for splitting the light beam into a plurality of beams including a main beam and two side beams is formed integrally with the optical member.
As the light beam splitting means for diffracting and splitting the light beam directed toward the optical disc into a plurality of beams is provided, as described above, the integrated optical element according to the present invention forms spots of the main beam and two side beams onto the signal recording surface of the optical disc and detects the return light beams thereof. Thus, a tracking error signal can be generated by a so-called three-beam method.
Moreover, as the light beam splitting means is formed integrally with the optical member, as described above, the integrated optical element according to the present invention can realize miniaturization of the integrated optical element itself and miniaturization of the optical pickup using this integrated optical element.
Also, in the integrated optical element according to the present invention, it is desired that at least one light-receiving section of the photodetector is divided by division lines substantially parallel to the boundary of the diffraction areas of the optical path branching means.
As at least one light-receiving section of the photodetector is divided by the division lines substantially parallel to the boundary of the diffraction areas of the optical path branching means, as described above, the integrated optical element according to the present invention can effectively restrain generation of any deviation of the signal level of the focusing error signal due to a position change of the return light spot and detect an appropriate focusing error signal even in the case where the position of the return light spot of the light beam in a focused state on the photodetector is somewhat changed by a change in the oscillation wavelength of the light source or by a change in the refractive index of the optical member due to a temperature change.
Another integrated optical element according to the present invention, used for an optical pickup for carrying out recording and/or reproduction of signals by irradiating a signal recording surface of an optical disc with a light beam, includes: a light source for emitting the light beam; a photodetector having a light-receiving section for receiving a return light beam reflected by the signal recording surface of the optical disc; a package member for housing the light source and the photodetector therein; an optical member arranged on the package member for transmitting the light beam emitted from the light source and for transmitting the return light beam directed toward the photodetector; optical path branching means integrally formed with the optical member for separating the optical path of the light beam emitted from the light source and the optical path of the return light beam reflected by the signal recording surface of the optical disc; and return light beam splitting means integrally formed with the optical member for splitting the return light beam passed through the optical path branching means into at least two beams.
In this integrated optical element, the return light beam splitting means has at least two surfaces having different normal vectors, and the boundary between these surfaces is inclined at a predetermined angle with respect to a direction corresponding to the direction of radius of the optical disc. At least one light-receiving section of the photodetector is divided into a portion for receiving one return light beam generated by the return light beam splitting means and a portion for receiving the other return light beam.
In this another integrated optical element according to the present invention, the light source is housed inside the package member and emits the light beam for irradiating the signal recording surface of the optical disc. The light beam emitted from the light source is transmitted through the optical member provided on the package member. Then, the light beam transmitted through the optical member is converged by light beam converging means of the optical pickup and then cast onto the signal recording surface of the optical disc.
The light beam cast on the signal recording surface of the optical disc is reflected by the signal recording surface of the optical disc and thus becomes a return light beam including a signal component. The return light beam passes again through the light beam converging means and then becomes incident on the optical member.
The return light beam incident on the optical member has its optical path separated from the optical path of the light beam emitted from the light source, by the optical path branching means formed integrally with the optical member. Specifically, the optical path branching means includes, for example, a hologram formed on the surface of the optical member. As the return light beam is diffracted by the hologram into the direction toward the photodetector, the optical path of the return light beam is separated from the optical path of the light beam emitted from the light source.
The return light beam having its optical path branched by the optical path branching means is then split into at least two beams by the return light beam splitting means integrally formed with the optical member.
Since the return light beam splitting means has at least two surfaces having different normal vectors, the return light beam incident on the return light beam splitting means is split along the boundary between the surfaces. The beams generated by splitting proceed in different directions in accordance with the normal vectors of the surfaces on which they are incident, and are directed toward the photodetector housed in the package member.
Since at least one light receiving section of the photodetector is divided into the portion for receiving one return light beam generated by the return light beam splitting means and the portion for receiving the other return light beam, the return light beams generated by the return light beam splitting means are received by the corresponding portions of the light-receiving section of the photodetector.
Thus, on the basis of the detection signal from the light-receiving section of the photodetector, a reproduction signal is generated and a focusing error signal is generated by a so-called Foucault method.
Meanwhile, in the case where the position of the light beam converging means with respect to the integrated optical element is deviated in the direction of radius of the optical disc from the normal position at the time of access to a desired recording track on the optical disc, the spot of the return light beam incident on the optical member is deviated in the direction corresponding to the direction of radius of the optical disc, on the optical path branching means.
In this another integrated optical element according to the present invention, the return light beam splitting means has at least two surfaces of different normal vectors and the boundary between these surfaces is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. Therefore, in the case where the position of the light beam converging means is deviated in the direction of radius of the optical disc from the normal position, the return light beam is split asymmetrically by the return light beam splitting means. The individual parts of the return light beam generated by asymmetrical splitting by the return light beam splitting means are received by the corresponding portions of the light-receiving section of the photodetector. Therefore, the position deviation of the light beam converging means with respect to the integrated optical element can be detected on the basis of the detection signal from the light-receiving section of the photodetector.
According to this another integrated optical element of the present invention, since the position deviation of the light beam converging means with respect to the integrated optical element at the time of access to a desired recording track on the optical disc can be detected in the above-described manner, the optical pickup using this integrated optical element can realize the high-speed access property.
Also, in this another integrated optical element, the return light beam splitting means for generating a focusing error signal by the Foucault method is used for detecting the position deviation of the light beam converging means with respect to the integrated optical element, instead of additionally providing any means for detecting the position deviation of the light beam converging means. Therefore, the optical pickup using this integrated optical element can realize the high-speed access property by appropriately and simply detecting the position deviation of the light beam converging means, without causing the increase in the number of components, the increase in the size of the device itself and the rise in cost.
In this another integrated optical element according to the present invention, it is desired that light beam splitting means for diffracting the light beam directed toward the optical disc and for splitting the light beam into a plurality of beams including a main beam and two side beams is formed integrally with the optical member.
As the light beam splitting means for diffracting and splitting the light beam directed toward the optical disc into a plurality of beams is provided, as described above, this another integrated optical element according to the present invention forms spots of the main beam and two side beams onto the signal recording surface of the optical disc and detects the return light beams thereof. Thus, a tracking error signal can be generated by a so-called three-beam method.
Moreover, as the light beam splitting means is formed integrally with the optical member, as described above, this another integrated optical element according to the present invention can realize miniaturization of the integrated optical element itself and miniaturization of the optical pickup using this integrated optical element.
Also, in this another integrated optical element according to the present invention, it is desired that at least one light-receiving section of the photodetector is divided by division lines substantially parallel to the boundary of the return light beam splitting means.
As at least one light-receiving section of the photodetector is divided by the division lines substantially parallel to the boundary of the diffraction areas of the optical path branching means, as described above, the integrated optical element according to the present invention can effectively restrain generation of any deviation of the signal level of the focusing error signal due to a position change of the return light spot and detect an appropriate focusing error signal even in the case where the position of the return light spot of the light beam in a focused state on the photodetector is somewhat changed by a change in the oscillation wavelength of the light source or by a change in the refractive index of the optical member due to a temperature change.
An optical pickup according to the present invention for carrying out recording and/or reproduction of signals by irradiating a signal recording surface of an optical disc with a light beam includes: a light source for emitting the light beam; light beam converging means for converging the light beam emitted from the light source and for irradiating the signal recording surface of the optical disc with the converged light beam; a photodetector having a light-receiving section for receiving a return light beam reflected by the signal recording surface of the optical disc; an optical member arranged between the light source and photodetector on one side and the light beam converging means on the other side, for transmitting the light beam emitted from the light source and for transmitting the return light beam directed toward the photodetector; optical path branching means integrally formed with the optical member for separating the optical path of the light beam emitted from the light source and the optical path of the return light beam directed toward the photodetector; and a biaxial actuator for moving the light beam converging means into biaxial directions, that is, the direction of radius of the optical disc and the direction toward and away from the optical disc.
In this optical pickup, the optical path branching means has at least two diffraction areas for diffracting the return light beam reflected by the signal recording surface of the optical disc, into different directions, respectively, and the boundary between the diffraction areas is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. At least one light-receiving section of the photodetector is divided into a portion for receiving a return light beam diffracted by one diffraction area of the optical path branching means and a portion for receiving a return light beam diffracted by the other diffraction area.
In the optical pickup according to the present invention, the light beam emitted from the light source is transmitted through the optical member and directed toward the light beam converging means. The light beam is then converged by light beam converging means and then cast onto the signal recording surface of the optical disc.
In the case where the spot of the light beam cast on the signal recording surface of the optical disc is deviated from a predetermined recording track on the signal recording surface of the optical disc, or in the case where no focal point is formed on the signal recording surface of the optical disc, the biaxial actuator is driven on the basis of a tracking error signal or a focusing error signal, and the light beam converging means is moved by the biaxial actuator into the direction of radius of the optical disc or into the direction toward and away from the optical disc. Thus, the spot of the light beam converged by the light beam converging means and cast onto the signal recording surface of the optical disc constantly follows a predetermined recording track on the signal recording surface of the optical disc and forms a focal point on the signal recording surface of the optical disc.
The light beam cast on the signal recording surface of the optical disc is reflected by the signal recording surface of the optical disc and thus becomes a return light beam including a signal component. The return light beam passes again through the light beam converging means and then becomes incident on the optical member.
The return light beam incident on the optical member has its optical path separated from the optical path of the light beam emitted from the light source, by the optical path branching means formed integrally with the optical member. Specifically, the optical path branching means includes, for example, a hologram formed on the surface of the optical member. As the return light beam is diffracted by the hologram into the direction toward the photodetector, the optical path of the return light beam is separated from the optical path of the light beam emitted from the light source.
Since the optical path branching means has at least two diffraction areas for diffracting the return light beam in different directions, the return light beams incident on the respective diffraction areas of the optical path branching means are diffracted into different directions by the diffraction areas of the optical path branching means, then transmitted through the optical member, and directed toward the photodetector.
Since at least one light receiving section of the photodetector is divided into the portion for receiving the return light beam diffracted by one diffraction area of the optical path branching means and the portion for receiving the return light beam diffracted by the other diffraction area, the return light beams diffracted into different directions by the respective diffraction areas of the optical path branching means are received by the corresponding portions of the light-receiving section of the photodetector.
Thus, on the basis of the detection signal from the light-receiving section of the photodetector, a reproduction signal is generated and a focusing error signal is generated by a so-called Foucault method.
Meanwhile, in the case where the position of the light beam converging means with respect to the optical member is deviated in the direction of radius of the optical disc from the normal position at the time of access to a desired recording track on the optical disc, the spot of the return light beam incident on the optical member is deviated in the direction corresponding to the direction of radius of the optical disc, on the optical path branching means.
In the optical pickup according to the present invention, the optical path branching means has at least two diffraction areas for diffracting the return light beam into different directions, and the boundary between these diffraction areas is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. Therefore, in the case where the position of the light beam converging means is deviated in the direction of radius of the optical disc from the normal position, the return light beam is split asymmetrically by the optical path branching means. The individual parts of the return light beam generated by asymmetrical splitting by the optical path branching means are received by the corresponding portions of the light-receiving section of the photodetector. Therefore, the position deviation of the light beam converging means with respect to the optical member can be detected on the basis of the detection signal from the light-receiving section of the photodetector.
According to the optical pickup of the present invention, since the position deviation of the light beam converging means with respect to the optical member at the time of access to a desired recording track on the optical disc can be detected in the above-described manner, the position of the light beam converging means can be instantaneously recovered to secure the accuracy and stability of the access operation and to realize the high-speed access property.
Also, in this optical pickup according to the present invention, the optical path branching means for separating the optical path of the return light beam directed toward the photodetector from the optical path of the light beam emitted from the light source and for generating a focusing error signal by the Foucault method is used for detecting the position deviation of the light beam converging means with respect to the optical member, instead of additionally providing any means for detecting the position deviation of the light beam converging means. Therefore, the optical pickup can realize the high-speed access property by appropriately and simply detecting the position deviation of the light beam converging means, without causing the increase in the number of components, the increase in the size of the device itself and the rise in cost.
Another optical pickup according to the present invention for carrying out recording and/or reproduction of signals by irradiating a signal recording surface of an optical disc with a light beam includes: a light source for emitting the light beam; light beam converging means for converging the light beam emitted from the light source and for irradiating the signal recording surface of the optical disc with the converged light beam; a photodetector having a light-receiving section for receiving a return light beam reflected by the signal recording surface of the optical disc; an optical member arranged between the light source and photodetector on one side and the light beam converging means on the other side, for transmitting the light beam emitted from the light source and for transmitting the return light beam directed toward the photodetector; optical path branching means integrally formed with the optical member for separating the optical path of the light beam emitted from the light source and the optical path of the return light beam reflected by the signal recording surface of the optical disc; return light beam splitting means integrally formed with the optical member for splitting the return light beam passed through the optical path branching means into at least two beams; and a biaxial actuator for moving the light beam converging means into biaxial directions, that is, the direction of radius of the optical disc and the direction toward and away from the optical disc.
In this optical pickup, the return light beam splitting means has at least two surfaces having different normal vectors, and the boundary between these surfaces is inclined at a predetermined angle with respect to a direction corresponding to the direction of radius of the optical disc. At least one light-receiving section of the photodetector is divided into a portion for receiving one return light beam generated by the return light beam splitting means and a portion for receiving the other return light beam.
In this another optical member according to the present invention, the light beam emitted from the light source is transmitted through the optical member and directed toward the light beam converging means. Then, the light beam is converged by light beam converging means and then cast onto the signal recording surface of the optical disc.
In the case where the spot of the light beam cast on the signal recording surface of the optical disc is deviated from a predetermined recording track on the signal recording surface of the optical disc, or in the case where no focal point is formed on the signal recording surface of the optical disc, the biaxial actuator is driven on the basis of a tracking error signal or a focusing error signal, and the light beam converging means is moved by the biaxial actuator into the direction of radius of the optical disc or into the direction toward and away from the optical disc. Thus, the spot of the light beam converged by the light beam converging means and cast onto the signal recording surface of the optical disc constantly follows a predetermined recording track on the signal recording surface of the optical disc and forms a focal point on the signal recording surface of the optical disc.
The light beam cast on the signal recording surface of the optical disc is reflected by the signal recording surface of the optical disc and thus becomes a return light beam including a signal component. The return light beam passes again through the light beam converging means and then becomes incident on the optical member.
The return light beam incident on the optical member has its optical path separated from the optical path of the light beam emitted from the light source, by the optical path branching means formed integrally with the optical member. Specifically, the optical path branching means includes, for example, a hologram formed on the surface of the optical member. As the return light beam is diffracted by the hologram into the direction toward the photodetector, the optical path of the return light beam is separated from the optical path of the light beam emitted from the light source.
The return light beam having its optical path branched by the optical path branching means is then split into at least two beams by the return light beam splitting means integrally formed with the optical member.
Since the return light beam splitting means has at least two surfaces having different normal vectors, the return light beam incident on the return light beam splitting means is split along the boundary between the surfaces. The beams generated by splitting proceed in different directions in accordance with the normal vectors of the surfaces on which they are incident, and are directed toward the photodetector.
Since at least one light receiving section of the photodetector is divided into the portion for receiving one return light beam generated by the return light beam splitting means and the portion for receiving the other return light beam, the return light beams generated by the return light beam splitting means are received by the corresponding portions of the light-receiving section of the photodetector.
Thus, on the basis of the detection signal from the light-receiving section of the photodetector, a reproduction signal is generated and a focusing error signal is generated by a so-called Foucault method.
Meanwhile, in the case where the position of the light beam converging means with respect to the optical member is deviated in the direction of radius of the optical disc from the normal position at the time of access to a desired recording track on the optical disc, the spot of the return light beam incident on the optical member is deviated in the direction corresponding to the direction of radius of the optical disc, on the optical path branching means.
In this another optical pickup according to the present invention, the return light beam splitting means has at least two surfaces of different normal vectors and the boundary between these surfaces is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. Therefore, in the case where the position of the light beam converging means is deviated in the direction of radius of the optical disc from the normal position, the return light beam is split asymmetrically by the return light beam splitting means. The individual parts of the return light beam generated by asymmetrical splitting by the return light beam splitting means are received by the corresponding portions of the light-receiving section of the photodetector. Therefore, the position deviation of the light beam converging means with respect to the optical member can be detected on the basis of the detection signal from the light-receiving section of the photodetector.
According to this another optical pickup of the present invention, since the position deviation of the light beam converging means with respect to the optical member at the time of access to a desired recording track on the optical disc can be detected in the above-described manner, the position of the light beam converging means can be instantaneously recovered to secure the accuracy and stability of the access operation and to realize the high-speed access property.
Also, in this another optical pickup according to the present invention, the return light beam splitting means for generating a focusing error signal by the Foucault method is used for detecting the position deviation of the light beam converging means with respect to the optical member, instead of additionally providing any means for detecting the position deviation of the light beam converging means. Therefore, the optical pickup can realize the high-speed access property by appropriately and simply detecting the position deviation of the light beam converging means, without causing the increase in the number of components, the increase in the size of the device itself and the rise in cost.
An optical disc device according to the present invention includes: disc rotating means for rotating an optical disc; an optical pickup for carrying out recording and/or reproduction of signals by irradiating with a light beam a signal recording surface of the optical disc rotated by the disc rotating means; a signal processing circuit for processing a detection signal from the optical pickup; and an access mechanism for moving the optical pickup in the direction of radius of the optical disc.
In this optical disc device, the optical pickup includes a light source for emitting the light beam, light beam converging means for converging the light beam emitted from the light source and for irradiating the signal recording surface of the optical disc with the converged light beam, a photodetector having a light-receiving section for receiving a return light beam reflected by the signal recording surface of the optical disc, an optical member arranged between the light source and photodetector on one side and the light beam converging means on the other side, for transmitting the light beam emitted from the light source and for transmitting the return light beam directed toward the photodetector, optical path branching means integrally formed with the optical member for separating the optical path of the light beam emitted from the light source and the optical path of the return light beam directed toward the photodetector, and a biaxial actuator for moving the light beam converging means into biaxial directions, that is, the direction of radius of the optical disc and the direction toward and away from the optical disc. The optical path branching means has at least two diffraction areas for diffracting the return light beam reflected by the signal recording surface of the optical disc, into different directions, respectively, and the boundary between the diffraction areas is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. At least one light-receiving section of the photodetector is divided into a portion for receiving a return light beam diffracted by one diffraction area of the optical path branching means and a portion for receiving a return light beam diffracted by the other diffraction area.
In the optical disc device according to the present invention, the optical disc as a recording medium is rotated by the disc rotating means. Then, when signals are to be recorded to and/or reproduced from the optical disc rotated by the disc rotating means, a light beam is first emitted from the light source of the optical pickup to the optical disc rotated by the disc rotating means. The optical pickup is moved in the direction of radius of the optical disc by the access mechanism so as to access a desired recording track.
The light beam emitted from the light source is transmitted through the optical member and directed toward the light beam converging means. The light beam is then converged by light beam converging means and then cast onto the signal recording surface of the optical disc.
In the case where the spot of the light beam cast on the signal recording surface of the optical disc is deviated from a predetermined recording track on the signal recording surface of the optical disc, or in the case where no focal point is formed on the signal recording surface of the optical disc, the biaxial actuator is driven on the basis of a tracking error signal or a focusing error signal from the signal processing circuit, and the light beam converging means is moved by the biaxial actuator into the direction of radius of the optical disc or into the direction toward and away from the optical disc. Thus, the spot of the light beam converged by the light beam converging means and cast onto the signal recording surface of the optical disc constantly follows a predetermined recording track on the signal recording surface of the optical disc and forms a focal point on the signal recording surface of the optical disc.
The light beam cast on the signal recording surface of the optical disc is reflected by the signal recording surface of the optical disc and thus becomes a return light beam including a signal component. The return light beam passes again through the light beam converging means and then becomes incident on the optical member.
The return light beam incident on the optical member has its optical path separated from the optical path of the light beam emitted from the light source, by the optical path branching means formed integrally with the optical member. Specifically, the optical path branching means includes, for example, a hologram formed on the surface of the optical member. As the return light beam is diffracted by the hologram into the direction toward the photodetector, the optical path of the return light beam is separated from the optical path of the light beam emitted from the light source.
Since the optical path branching means has at least two diffraction areas for diffracting the return light beam in different directions, the return light beams incident on the respective diffraction areas of the optical path branching means are diffracted into different directions by the diffraction areas of the optical path branching means, then transmitted through the optical member, and directed toward the photodetector.
Since at least one light receiving section of the photodetector is divided into the portion for receiving the return light beam diffracted by one diffraction area of the optical path branching means and the portion for receiving the return light beam diffracted by the other diffraction area, the return light beams diffracted into different directions by the respective diffraction areas of the optical path branching means are received by the corresponding portions of the light-receiving section of the photodetector.
The return light beams received by the respective portions of the light-receiving section of the photodetector are photoelectrically converted by the photodetector and supplied as detection signals to the signal processing circuit. In the signal processing circuit, predetermined arithmetic processing is carried out on the basis of the detection signal, thereby generating a reproduction signal and generating a focusing error signal by a so-called Foucault method.
Meanwhile, in the case where signals are to be recorded to and/or reproduced from the optical disc in this optical disc device, first the optical pickup is moved in the direction of radius by the access mechanism so as to access a desired recording track, as described above. In this case, the position of the light beam converging means of the optical pickup with respect to the optical member may be deviated into the direction of radius of the optical disc from the normal position because of inertia. When the position of the light beam converging means with respect to the optical member is deviated in the direction of radius of the optical disc from the normal position, the spot of the return light beam incident on the optical member is deviated in the direction corresponding to the direction of radius of the optical disc, on the optical path branching means.
In the optical disc device according to the present invention, the optical path branching means of the optical pickup has at least two diffraction areas for diffracting the return light beam into different directions, and the boundary between these diffraction areas is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. Therefore, in the case where the position of the light beam converging means is deviated in the direction of radius of the optical disc from the normal position, the return light beam is split asymmetrically by the optical path branching means. The individual parts of the return light beam generated by asymmetrical splitting by the optical path branching means are received by the corresponding portions of the light-receiving section of the photodetector. Therefore, the position deviation of the light beam converging means with respect to the optical member can be detected by carrying out predetermined arithmetic processing in the signal processing circuit on the basis of the detection signal from the light-receiving section of the photodetector.
According to the optical disc device of the present invention, since the position deviation of the light beam converging means with respect to the optical member at the time when causing the optical pickup to access a desired recording track on the optical disc can be detected in the above-described manner, the position of the light beam converging means can be instantaneously recovered to secure the accuracy and stability of the access operation and to realize the high-speed access property.
Also, in this optical disc device according to the present invention, the optical path branching means of the optical pickup for separating the optical path of the return light beam directed toward the photodetector from the optical path of the light beam emitted from the light source and for generating a focusing error signal by the Foucault method is used for detecting the position deviation of the light beam converging means with respect to the optical member, instead of additionally providing any means for detecting the position deviation of the light beam converging means. Therefore, the optical disc device can realize the high-speed access property by appropriately and simply detecting the position deviation of the light beam converging means, without causing the increase in the number of components, the increase in the size of the device itself and the rise in cost.
Another optical disc device according to the present invention includes: disc rotating means for rotating an optical disc; an optical pickup for carrying out recording and/or reproduction of signals by irradiating with a light beam a signal recording surface of the optical disc rotated by the disc rotating means; a signal processing circuit for processing a detection signal from the optical pickup; and an access mechanism for moving the optical pickup in the direction of radius of the optical disc.
In this optical disc device, the optical pickup includes a light source for emitting the light beam, light beam converging means for converging the light beam emitted from the light source and for irradiating the signal recording surface of the optical disc with the converged light beam, a photodetector having a light-receiving section for receiving a return light beam reflected by the signal recording surface of the optical disc, an optical member arranged between the light source and photodetector on one side and the light beam converging means on the other side, for transmitting the light beam emitted from the light source and for transmitting the return light beam directed toward the photodetector, optical path branching means integrally formed with the optical member for separating the optical path of the light beam emitted from the light source and the optical path of the return light beam reflected by the signal recording surface of the optical disc, return light beam splitting means integrally formed with the optical member for splitting the return light beam passed through the optical path branching means into at least two beams, and a biaxial actuator for moving the light beam converging means into biaxial directions, that is, the direction of radius of the optical disc and the direction toward and away from the optical disc. The return light beam splitting means has at least two surfaces having different normal vectors, and the boundary between these surfaces is inclined at a predetermined angle with respect to a direction corresponding to the direction of radius of the optical disc. At least one light-receiving section of the photodetector is divided into a portion for receiving one return light beam generated by the return light beam splitting means and a portion for receiving the other return light beam.
In this another optical disc device according to the present invention, the optical disc as a recording medium is rotated by the disc rotating means. Then, when signals are to be recorded to and/or reproduced from the optical disc rotated by the disc rotating means, a light beam is first emitted from the light source of the optical pickup to the optical disc rotated by the disc rotating means. The optical pickup is moved in the direction of radius of the optical disc by the access mechanism so as to access a desired recording track.
The light beam emitted from the light source is transmitted through the optical member and directed toward the light beam converging means. The light beam is then converged by light beam converging means and then cast onto the signal recording surface of the optical disc.
In the case where the spot of the light beam cast on the signal recording surface of the optical disc is deviated from a predetermined recording track on the signal recording surface of the optical disc, or in the case where no focal point is formed on the signal recording surface of the optical disc, the biaxial actuator is driven on the basis of a tracking error signal or a focusing error signal from the signal processing circuit, and the light beam converging means is moved by the biaxial actuator into the direction of radius of the optical disc or into the direction toward and away from the optical disc. Thus, the spot of the light beam converged by the light beam converging means and cast onto the signal recording surface of the optical disc constantly follows a predetermined recording track on the signal recording surface of the optical disc and forms a focal point on the signal recording surface of the optical disc.
The light beam cast on the signal recording surface of the optical disc is reflected by the signal recording surface of the optical disc and thus becomes a return light beam including a signal component. The return light beam passes again through the light beam converging means and then becomes incident on the optical member.
The return light beam incident on the optical member has its optical path separated from the optical path of the light beam emitted from the light source, by the optical path branching means formed integrally with the optical member. Specifically, the optical path branching means includes, for example, a hologram formed on the surface of the optical member. As the return light beam is diffracted by the hologram into the direction toward the photodetector, the optical path of the return light beam is separated from the optical path of the light beam emitted from the light source.
The return light beam having its optical path branched by the optical path branching means is then split into at least two beams by the return light beam splitting means integrally formed with the optical member.
Since the return light beam splitting means has at least two surfaces having different normal vectors, the return light beam incident on the return light beam splitting means is split along the boundary between the surfaces. The beams generated by splitting proceed in different directions in accordance with the normal vectors of the surfaces on which they are incident, and are directed toward the photodetector.
Since at least one light receiving section of the photodetector is divided into the portion for receiving one return light beam generated by the return light beam splitting means and the portion for receiving the other return light beam, the return light beams generated by the return light beam splitting means are received by the corresponding portions of the light-receiving section of the photodetector.
The return light beams received by the respective portions of the light-receiving section of the photodetector are photoelectrically converted by the photodetector and supplied as detection signals to the signal processing circuit. In the signal processing circuit, predetermined arithmetic processing is carried out on the basis of the detection signal, thereby generating a reproduction signal and generating a focusing error signal by a so-called Foucault method.
Meanwhile, in the case where signals are to be recorded to and/or reproduced from the optical disc in this optical disc device, first the optical pickup is moved in the direction of radius by the access mechanism so as to access a desired recording track, as described above. In this case, the position of the light beam converging means of the optical pickup with respect to the optical member may be deviated into the direction of radius of the optical disc from the normal position because of inertia. When the position of the light beam converging means with respect to the optical member is deviated in the direction of radius of the optical disc from the normal position, the spot of the return light beam incident on the optical member is deviated in the direction corresponding to the direction of radius of the optical disc, on the optical path branching means.
In this another optical disc device according to the present invention, the return light beam splitting means of the optical pickup has at least two surfaces of different normal vectors and the boundary between these surfaces is inclined at a predetermined angle with respect to the direction corresponding to the direction of radius of the optical disc. Therefore, in the case where the position of the light beam converging means is deviated in the direction of radius of the optical disc from the normal position, the return light beam is split asymmetrically by the return light beam splitting means. The individual parts of the return light beam generated by asymmetrical splitting by the return light beam splitting means are received by the corresponding portions of the light-receiving section of the photodetector. Therefore, the position deviation of the light beam converging means with respect to the optical member can be detected by carrying out predetermined arithmetic processing in the signal processing circuit on the basis of the detection signal from the light-receiving section of the photodetector.
According to this another optical disc device of the present invention, since the position deviation of the light beam converging means with respect to the optical member at the time when causing the optical pickup to access a desired recording track on the optical disc can be detected in the above-described manner, the position of the light beam converging means can be instantaneously recovered to secure the accuracy and stability of the access operation and to realize the high-speed access property.
Also, in this another optical disc device according to the present invention, the return light beam splitting means of the optical pickup for generating a focusing error signal by the Foucault method is used for detecting the position deviation of the light beam converging means with respect to the optical member, instead of additionally providing any means for detecting the position deviation of the light beam converging means. Therefore, the optical disc device can realize the high-speed access property by appropriately and simply detecting the position deviation of the light beam converging means, without causing the increase in the number of components, the increase in the size of the device itself and the rise in cost.
FIG. 1 is a perspective view schematically showing a conventional optical pickup.
FIG. 2 is a view for explaining the deviation of an objective lens in the direction of radius of an optical disc at the time of access by the optical pickup.
FIG. 3 is a block diagram showing an exemplary structure of an optical disc device to which the present invention is applied.
FIG. 4 is a perspective view schematically showing an optical pickup to which the present invention is applied.
FIG. 5 is a side view schematically showing the state inside the optical pickup for explaining the positional relation of an integrated optical element to which the present invention is applied in the optical pickup.
FIG. 6 is a side view schematically showing the state inside the integrated optical element to which the present invention is applied.
FIG. 7 is a perspective view schematically showing the positional relation of individual members constituting the optical pickup to which the present invention is applied.
FIGS. 8A to 8C show the relation between the position of an objective lens in the optical pickup to which the present invention is applied and the position of a return light spot formed on a hologram. FIG. 8A shows the state where the objective lens is located at a normal position. FIGS. 8B and 8C show the state where the position of the objective lens is deviated.
FIG. 9 is a side view schematically showing the state inside another integrated optical element to which the present invention is applied.
FIG. 10 is a perspective view schematically showing the positional relation of individual members constituting another optical pickup to which the present invention is applied.
FIG. 11 is an enlarged perspective view showing essential portions of an optical member provided in another optical pickup to which the present invention is applied.
FIGS. 12A to 12C show the relation between the position of an objective lens in another optical pickup to which the present invention is applied and the position of a return light spot formed on a Foucault prism. FIG. 12A shows the state where the objective lens is located at a normal position. FIGS. 12B and 12C show the state where the position of the objective lens is deviated.
FIG. 13 is a side view schematically showing the state inside still another integrated optical element to which the present invention is applied.
FIG. 14 is a perspective view schematically showing the positional relation of individual members constituting still another optical pickup to which the present invention is applied.

Integrated optical element, optical pickup, and optical disk device


A system and method of phase compensating transient performance data are provided. Transient performance data are collected for a plurality of parameters, and two of the parameters are selected. A transfer function is applied to the transient performance data for at least one of the selected parameters to thereby generate phase compensated performance data that is representative of a steady state relationship between the selected parameters.

Performance analysis of various machines, such as aircraft gas turbine engines, is becoming increasingly desirable. This is because a performance analysis may be used in the development of new engines, as well as the monitoring of presently operating engines. In particular, in the context of presently operating engines, a performance analysis may be used to identify one or more components in an engine that may be adversely impacting engine performance.
Typically, a performance analysis of a gas turbine engine (or other machine) is conducted using steady state performance data. A performance analysis conducted using performance data collected from a machine that is not running in a sufficiently steady state condition will likely not be sufficiently accurate. This could have various undesirable effects. For example, it could lead to less than optimal component design or an inaccurate engine power capability assessment.
In the context of a gas turbine engine, steady state performance data are performance data that are collected after the engine achieves thermal equilibrium. In many instances an aircraft gas turbine engine may experience few, if any, truly steady state conditions due, or example, to changes in flight conditions or engine power setting. Thus, the limitation on using steady state performance data for a performance analysis can be potentially troublesome, since the collected data may not be steady state performance data. In such instances, a performance analysis engineer may need to choose between discarding the collected data entirely, or using non-steady state performance data and compromising the accuracy of the performance analysis.
Hence, there is a need for a system and method of conducting performance analysis of a machine, such as an aircraft gas turbine engine, using performance data that are not steady state performance data. The present invention addresses at least this need.

Transient performance data phase compensation system and method


A touch panel includes a substrate and a first electrode array. The first electrode array is disposed on the substrate and includes first and second touch regions. The first electrode array further includes first, second, third, and fourth electrodes. The first electrode is disposed on the first touch region. The second electrode is disposed on the first touch region corresponding in position to the first electrode. The third electrode is disposed on the second touch region. The fourth electrode is disposed on the second touch region corresponding in position to the third electrode. In addition, the first to fourth electrodes are all disposed on the same layer. The first electrode is disposed diagonally to the fourth electrode, and the first electrode is electrically coupled to the fourth electrode. Furthermore, a method for controlling the touch panel is also disclosed herein.

Field of Invention
The present invention relates to a panel and a method for controlling the same and, more particularly, to a touch device, a touch panel, and a method for controlling the same.
Description of Related Art
A touch panels is a type of human-machine interface. Due to the intuitive operation of touch panels, the connection between humans and machines is made more convenient, and as a result, touch panels have been developed in a progressive manner in recent years.
A single side with multilayer structure is typically used in touch panels. However, due to the multilayer membrane structure, when the single side with multilayer structure is used in a display product, light transmittance is reduced.
In addition, a single side with single layer structure is used in display products. However, when a conventional single side with single layer structure is used to detect multi touch, actual finger touching positions cannot be detected effectively.
There has been much effort in trying to find a solution to the aforementioned problems. Nonetheless, there is still a need to improve the existing apparatuses and techniques in the art.

Touch device, touch panel, and method for controlling the same


A rolled film capacitor is disclosed which includes a first dielectric film and a second dielectric film, which are wound along their length dimension to form alternating turns of the winding. A plurality of first conductive segments are arranged on a first surface of the first dielectric film along the length dimension of the first dielectric film, and a plurality of second conductive segments are arranged on a surface of the second dielectric film along the length dimension of the second dielectric film, or on a second surface of the first dielectric film along the length dimension of the first dielectric film. The first conductive segments can have a progressively increasing length along the length dimension of the first dielectric film, and the second conductive segments have a progressively increasing length along the length dimension of the first or second dielectric film. The number of the first and/or second conductive segments per turn of the winding can be equal to or more than one.

The capacitance of capacitors generally can reduce over time (e.g. due to self-healing, corrosion, or some other aging effects). This reduction may occur inhomogenously, such that after some time, some parts of the capacitor may have lost more capacitance than other parts. Similarly, if multiple capacitors or capacitor segments are connected either in parallel or in series, after some time, some of these capacitors or segments may have lost more capacitance than others.
Rolled film capacitors having internal series connections are known. In these capacitors, a metallization layer, which is provided on a surface of the rolled film, is divided in a lateral direction (i.e. orthogonal to the winding direction), such as to form multiple separate electrodes. Thereby, two or more series connected capacitors are formed in a single winding, such as with some of the electrodes floating, (i.e., being electrically unconnected to terminals). The floating electrodes subdivide the potential drop between two electrodes connected to opposite leads.
It is in some cases desired to divide the metallization layer also in the longitudinal direction (i.e. in the winding direction) into segments, which are separated by insulating regions. For example, U.S. Pat. No. 5,057,967 describes a rolled film capacitor with a metal electrode pattern including a number of rectangular island electrodes mutually separated by a plurality of lateral and longitudinal insulating gaps and regularly arrayed in both directions. Further capacitors are known from EP 0 225 822, DE 198 06 586, EP 0 640 996, GB 2276765, EP 0 838 078, U.S. Pat. No. 4,348,714, and U.S. Pat. No. 5,442,516. All of the disclosure of these documents are incorporated herein by reference in their entireties.
The segmentation of commercially available metallized films is can be made as follows: Oil or a similar substance is transferred onto the film surface in a regular pre-determined pattern. Then, metal is evaporated and deposited for forming the segments. Since the metal can only be deposited wherever there is no oil on the surface, the regions covered by the oil remain insulating and thus divide the segments. The oil can be applied using a printing roll having a fixed circumference. The printing roll rolls in the longitudinal direction of the film, which is to become the winding direction of the capacitor. Hence, all patterns are self-repeating in the winding direction with a period of the circumference of the printing roll.
In the above capacitor, the distribution of currents and voltages in the winding and, hence, the voltage levels may vary considerably among the segments if their capacitance becomes inhomogeneous. This can have consequences on the lifetime performance of the capacitor. For example, if a segment becomes damaged and loses a considerable amount of its capacitance, high overvoltages may occur in regions near the damaged segment. These overvoltages may accelerate the aging of these near regions and finally damage them as well. Even if the segments are connected by narrow metal bridges known as gates, the above consequences can still occur, at least after the fuse gates have melted.


A cosmetic powder composition including a silica-sunscreen aggregate has a smooth light texture and provides ultra sheer coverage as well as enhanced sun protection to the skin.

This invention relates to a cosmetic powder composition including a silica-sunscreen aggregate. The cosmetic powder composition has a smooth, light texture and provides ultra sheer coverage as well as enhanced sun protection to the skin.
The damaging effects of sunlight on the skin are well known. In order to help protect the skin from these harmful effects, sunscreen agents have been incorporated into cosmetic compositions which are applied to the skin. The incorporation of sunscreen agents into powder compositions has been limited however, by the negative textural attributes imparted by sunscreen agents to these compositions. For example, the incorporation of conventional sunscreen agents typically results in agglomeration of the powder composition, as well as an unpleasant oily feel on the skin.


A method for performing maintenance on an outer surface of at least one wind turbine part, such as a tower (2), a nacelle (3) or a wind turbine blade (5), of an offshore wind turbine (1) is disclosed. An access system (10) is transported to a site of the offshore wind turbine (1), and the access system (10) is transferred to a transition platform (6) at a lower part of the offshore wind turbine (1), while operating the offshore wind turbine (1) in accordance with a normal operating mode. Normal operation of the offshore wind turbine (1) is then stopped, and maintenance is performed on an outer surface of at least one wind turbine part (2, 3, 5) of the offshore wind turbine (1), using the access system (10). When the maintenance has been completed, normal operation of the offshore wind turbine (1) is restarted in accordance with a normal operating mode. Normal operation of the offshore wind turbine (1) is only stopped while the actual maintenance takes place. Thereby the loss in power production is minimised.

In wind turbines, it may be necessary to perform maintenance on outer surfaces of wind turbine parts, such as wind turbine blades, tower, nacelle, etc. On outer surfaces here refers to a part of the wind turbine reached via the outer surface and also comprises for example sensors, mechanical parts or lightening conductors arranged in or under the outer surface. Such maintenance may include inspection, repair, cleaning, coating or painting, replacement or addition of elements, etc. The maintenance typically requires that access is gained to the relevant outer surfaces of the relevant wind turbine parts, and this will often require that the rotor of the wind turbine is stopped, thereby stopping operation of the wind turbine and disrupting the power production of the wind turbine. This is costly and undesirable, and therefore the length of the time that operation of the wind turbine is stopped should be minimised.
In offshore wind turbines, it is difficult to reduce the length of the time that operation of the wind turbine is stopped due to maintenance of outer surfaces of the wind turbine parts, because a vessel must be pre-booked for transporting equipment and personnel required for performing the maintenance to the offshore site, and the equipment must be transferred to the wind turbine and the maintenance performed while suitable wind and weather conditions prevail. This will often lead to the rotor of the wind turbine, and thereby power production, of the wind turbine having to be stopped for a considerable period of time.
WO 2015/003694 A1 discloses a device for inspecting a wind turbine. The device comprises an inspection platform that can be moved vertically along a tower of a wind turbine, wherein the inspection platform comprises at least two modules pivotably connected to each other. The inspection platform can be moved by means of cables connected to the nacelle of the wind turbine.
WO 2004/081373 A2 discloses a maintenance platform for suspending supporting cables, particularly for servicing rotor blades of wind power plants. The maintenance platform is constructed of at least two partial platforms connected to one another via a pivot joint in a manner that enables them to pivot about a pivot axis.
EP 2 586 933 A1 discloses a working platform for an offshore wind energy plant. The working platform is configured to be mounted to an outside wall of the tower of the offshore wind energy plant.

Method for performing maintenance on a wind turbine part


An anode with a multi-layer structure including a first layer (21) having carbon as a main component, and a second layer (22) having lithium-ion conductivity and including a material as a main component thereof which can insert and extract lithium ions, or a multi-layer structure including a third layer (23) containing lithium in addition to the first layer and the second layer, and a lithium secondary battery including the same. The lithium secondary battery can be provided in which the battery capacity is substantially enhanced in the voltage range where the battery is actually used while maintaining the higher charge-discharge efficiency and the excellent cycle performance.

The widespread use of mobile terminals such as a cellular phone and a notebook-size personal computer recognizes the importance of secondary batteries acting as their power sources. These secondary batteries are required to be compact, light and high in their capacities, and to have performance hardly deteriorated after the repetition of the charging and discharging.
Although metal lithium may be used as the anode of the secondary battery in view of its higher energy density and lightness, a problem arises that needle crystals (dendrite) are deposited on the lithium surface of the metal lithium anode during the charging in the progress of the charge-discharge cycle, and the crystals penetrate the separator to cause the internal short-circuit, thereby shortening the battery life.
Further, use of lithium alloy having a composition formula of LixM ("M" is metal such as Al) as an anode is investigated. A problem also arises that pulverization of the anode is caused with the progress of the charge-discharge cycle thereby shortening the battery life because the lithium metal anode is swollen and contracted with the insertion and extraction of the lithium ion though it has a larger volume for the lithium ion insertion and extraction per a unit volume and thus has a larger capacity.
When a carbon material such as graphite and hard carbon capable of inserting and extracting the lithium ion is used as the anode, the energy density becomes lower because the graphite material has a lower capacity than the metal lithium and the lithium alloy, and the hard carbon has a larger irreversible capacity on the initial charging and discharging to decrease the charge-discharge efficiency though the charge-discharge cycle is excellent.
A number of investigations have been conducted for the purpose of improving the anode.
JP-A-2000-21392 discloses the electric contact between an anode containing a carbon material and metal such as Si, Ge and Sn or its oxide, and metal lithium during the fabrication of the battery to propose the improvement of the anti-over discharge performance and the cycle performance.
JP-A-11(1999)-135120 discloses use of a carbon material coated with particles made of Al, Sn or Sb as an anode to propose the improvement of the higher capacity, the higher voltage and the cycle performance.
JP-A-10(1998)-21964 discloses use of a material mainly containing chalcogen compounds having Al, Sn or Si or its oxide as an anode to propose the higher capacity, the elevation of the cycle performance and the improvement of the production efficiency.
JP-A-2000-182602 discloses a secondary battery anode including an anode sheet made of an amorphous oxide capable of inserting and extracting lithium and laminated with a metal foil mainly made of lithium to propose the higher capacity and the improvement of the anti-over discharge performance.
JP-A-2001-15172 discloses a secondary battery anode including an anode sheet made of a carbon material laminated with a metal foil mainly made of lithium to propose the higher capacity and the improvement of the charge-discharge efficiency.
However, these prior arts cause the following problems.
The techniques described in JP-A-2000-21392, JP-A-11(1999)-135120 and JP-A-10(1998)-21964 can hardly increase the energy densities of the batteries sufficiently high because the metals and the metal oxides have the higher irreversible capacities on the initial charging and discharging and the larger anode weights. When the metal is mixed with the carbon-based material, the operating voltage becomes lower compared with an anode made of only carbon, and the higher operating voltage can be hardly obtained because a voltage plateau which is typical to the metal appears on a discharge curve at a voltage higher than that of carbon so that the higher operating voltage can be hardly obtained. The lower limit voltages are fixed depending on uses in the lithium secondary battery. The decrease of the operating voltage narrows the usable region so that the capacity increase in the region where the battery is actually used can be hardly intended.
In the method described in JP-A-2000-21392, the added lithium is reacted with active functional groups on the carbon surface, adsorbed water on the carbon surface or moisture contained in the solvent or the electrolyte to form a film on the anode surface. The lithium contained in the film is electrochemically inactive and cannot contribute to the charge-discharge capacity so that the improvement of the charge-discharge efficiency is insufficient. The electric resistances of the films are large to increase the resistance of the battery so that the effective capacity of the battery rather decreases.
In both of the anode sheet made of the amorphous material and the anode sheet made of the carbon material in the methods described in JP-A-2000-182602 and JP-A-2001-15172, a bonding agent of the electrode is in direct contact with the lithium metal foil so that the bonding agent reacts with part of the lithium metal foil to form a highly resistant film.
Further, in the amorphous material sheet, the metal distribution inevitably becomes non-uniform in the microscopic scale resulting in the generation of the local concentration of the electric field. Because of these reasons, it is difficult to maintain the cycle performance at a higher level.
The following descriptions can be found in the above publications with respect to electrolytes. An electrolyte prepared by dissolving 0.4 weight part of LiBF4 and 12.1 weight part of LiPF6 into a mixed solvent composed of 65.5 weight part of diethyl carbonate and 22 weight part of ethylene carbonate is described in JP-A-2000-21392; an electrolyte prepared by dissolving 1 mol/liter of LiPF6 into a mixed solvent composed of ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1 is described in JP-A-11(1999)-135120; an electrolyte prepared by dissolving 1 mol/liter of LiPF6 into a mixed solvent composed of ethylene carbonate and diethyl carbonate in a volume ratio of 2:8 is described in JP-A-10(1998)-21964; an electrolyte prepared by dissolving 0.4 g of LiBF4 and 12.1 g of LiPF6 into a mixed solvent composed of 65.3 g of diethyl carbonate and 22.2 g of ethylene carbonate is described in JP-A-2000-182602; and an electrolyte prepared by dissolving 0.4 g of LiBF4 and 12.1 g of LiPF6 into a mixed solvent composed of 65.3 g of diethyl carbonate and 22.2 g of ethylene carbonate followed by further dissolution of an adding agent such as 1,2-bis(ethoxycarbonyl)-1,2-dimethylhydrazine is described in JP-A-2001-15172. These electrolytes are described in the respective examples of the publications. Further, various solvents are cited and described to be used as an electrolyte in the bodies of the specifications.
However, the detailed review with respect to the optimum value and range regarding the solvent composition of the electrolyte, the volume ratio for mixing and the lithium salt concentration is not provided.


Headphones or a headset to enable active noise cancellation or binaural recording. Microphone signals are multiplexed within the headphones/headset and are conveyed to an attached device using a single contact point in the audio plug. The audio plug may be a conventional four connector audio plug to provide backwards compatibility. The multiplexing is analog multiplexing, and may be time-domain or frequency-domain multiplexing.

Higher-end headphones and headsets sometimes feature active noise cancellation (ANC). Headphones with ANC typically require two or more microphones and complex circuitry or processing to create suitable cancellation or compensation signals to be fed to the earphones. This often also requires battery power within the headphones or headset, which is inconvenient. Attempts to do ANC processing outside of the headphones or headset have typically involved digitization of the microphone signals, or customization of the audio jack (i.e. plug-and-socket) to add additional non-standard connectors in order to route the microphone signals. However, this adds extra cost or the need for special audio jacks that are not backwards compatible with existing equipment.
Similar reference numerals may have been used in different figures to denote similar components.

Headphones using multiplexed microphone signals to enable active noise cancellation