Patent Application
20080056076
It is to be understood that the drawings are to be used for the purposes of exemplary illustration only and not as a definition of the limits of the invention. Throughout the disclosure, the word “exemplary” is used exclusively to mean “serving as an example, instance, or illustration.” Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.
Referring to the drawings in which like reference character(s) present corresponding parts throughout:
The detailed description set forth below in connection with the appended drawings is intended as a description of presently preferred embodiments of the invention and is not intended to represent the only forms in which the present invention may be constructed and/or utilized.
As a detailed example of an optical pickup device according to the present invention, an optical disc reading device using the optical pickup device is explained. However, the optical pickup device according to the present invention can be not only used in the optical disc reading device but also applied to whatever the optical pickup device is used. Embodiments of the present invention will be explained according to an order described below.
A. First embodiment
B. Summary of the first embodiment
C. Second embodiment
D. Summary of the second embodiment
In what follows, an outline of components and functions of an optical disc reading device realizing the present invention is explained with referencing
According to the configuration described above, when a remote control 25 is operated with placing the optical disc 100 on the tray 20a to play the optical disc 100, a remote control interface 26b receives an operation signal output from the remote control 25 and outputs the operation signal to a microcomputer 26a through a bus 26k. When the microcomputer 26a accepts the operation signal, the loading motor 22 is driven for loading the tray 20a into the optical disc reading device 20. Next, the microcomputer 26a drives the spindle motor 21 to rotate the optical disc 100. Further, the microcomputer 26a selects a suitable objective lens of the optical pickup device 10 corresponding to the optical disc 100 which is going to be played.
Hollows called pits are formed on a recording surface of the optical disc 100 and the optical pickup device 10 irradiates a laser beam to the pits and reads data by detecting the laser beam reflected by the optical disc 100. Then the transferring control unit 23 controls a position of the optical pickup device 10, and the optical pickup device 10 is controlled so as to follow the pits of the optical disc 100 on rotating. The laser beam irradiated to the optical disc 100 is reflected and outgoing through a route same as the incoming route to the optical disc 100. The laser beam 10 irradiated to the optical disc 100 is reflected by the optical disc 100. And the laser beam 10 reflected by the optical disc 100 is detected by a detector and converted to digital video signals and digital sound signals. The digital video and sound signals are sent to the control board 26. In this specification, detailed explanations for data playing and data recording by the control board 26 are omitted because they are well known technologies. The digital video signals are sent to a video reproduction unit 26e. The video reproduction unit 26e generates image data corresponding to every frame, the image data is sent to external equipment through an input/output [I/O] terminal 26d with temporarily buffering in a buffer memory 26f.
At the same time, the sound signals acquired by the control board 26 are converted to sound data by a sound generator 26g. In the same manner, the sound data is sent to external equipment through an input/output [I/O] terminal 26d and buffered in a buffer memory 26h. Further if the video data and the sound data will be recorded at a hard disc drive [HDD] 26c of the optical disc reading device 20, the video data and the sound data buffered in the buffer memory 26f, 26h are written at predetermined addresses of the HDD 26c based on instructions by of the microcomputer 26a.
A configuration of the optical pickup device 10 will be explained below.
To realize the functions of the optical pickup device 10, the optical pickup device 10 is comprised of a laser diode 11, a couple of objective lenses 12a, 12b, a lens holder 13, an optical system 14, a position adjusting mechanism 15 and a detector 16. The laser diode 11 generates the laser beam. The objective lenses 12a, 12b focus the incoming laser beam. The lens holder 13 holds the objective lenses 12a, 12b. The optical system 14 reflects the laser beam from the laser diode 11 to irradiate the laser beam to the objective lenses 12a, 12b. The position adjusting mechanism 15 moves the lens holder 13 along a focusing direction perpendicular to the optical disc 100 and a tracking direction parallel to the optical disc 100 in order to follow the pits on rotating. Therefore, it is possible to accurately irradiate the laser beam to the rotating pits. The detector detects the laser beam reflected by the optical disc 100. The objective lenses 12a, 12b have different focal lengths and focal amounts. It can be possible to change the focal length and the focal amount corresponding to a kind of the optical discs by alternating the objective lenses 12a, 12b. Therefore, the optical pickup device 10 can read two or three kinds of the optical disc 100.
Further, the optical system 14 is comprised of a mirror 14a, a collimate lens 14b and a half mirror 14c. The laser beam irradiated by the laser diode 11 in transversal direction of
The laser beam irradiated to the pits on the optical disc 100 is reflected at the pits and irradiated to the half mirror 14c through same route as the incoming route. The half mirror 14c irradiates the laser beam to the detector 15 by reflection. The detector 15 detects incoming laser beam from the half mirror 14c and converts the laser beam detection to digital video signals. The video signals are output to the control board 26. The detector 15 in the present invention uses photo diodes to convert the laser beam detection to the digital video signals. Further, if the optical disc 100 having the recording surface geometrically different from that of previous optical disc 100 will be played, the position adjusting mechanism 15 switches the objective lenses 12a, 12b to be used by moving the lens holder 13. These procedures are executed by processing of the microcomputer 26a and this processing also realizes each function of the optical pickup device 10.
As explained above, the objective lenses 12a, 12b are switched by the position adjusting mechanism 15 for changing the focal length and the focal amount for focusing the incoming laser beam. The changing the focal length and the focal amount of the incoming laser beam enables to play a plural of kinds of the optical discs like the DVDs and the CDs having different geometry of recording surfaces. The objective lenses 12a, 12b have to be assembled to keep being parallel each other during assembling, because the position adjusting mechanism 15 adjusts the position of the lens holder 13 with the objective lenses 12a, 12b as a whole. It's preferable that adjusting each angles of the objective lenses 12a, 12b can easily be done during the assembling them. Therefore, the optical pickup device 10 as the first embodiment of the present invention is configured to be easily adjusted each inclination angles of the objective lenses 12a, 12b.
The configuration of the lens holder 13 will be explained below.
The first objective lenses 12a is placed to the first opening 13a1, the second objective lenses 12b is placed to the second opening 13b1. Then the inclination angle of the second objective lens 12b is adjusted to be substantially parallel to that of the first objective lenses 12a by using a spacer 13d. If the angles of the objective lenses 12a, 12b don't become substantially parallel each other, the angle of the second objective lens 12b is adjusted again by adjusting the spacer 13d. Therefore, the lens housing portions 13a, 13b and the spacer 13d have to be configured to make adjusting the inclination angle of the second objective lens 12b easy. The detail configuration of the lens housing portions 13a, 13b and the spacer 13d will be explained below.
The spacer 13d is configured to enable to adjust the inclination angle of the second objective lens 12b.
A method for adjusting the angle of the second objective lens 12b by tilting the spacer 13d will be explained below. According the method, the spacer 13d is provisionally fixed by a jig for adjusting with measuring the angle of the second objective lens 12b by a measurement apparatus like an autocollimator. Whatever can hold the spacer 13d and make the spacer 13d tilt and rotate as described below can be used as the jig.
Therefore a method described below is executed for adjusting the inclination angle of the second objective lens 12b. First the spacer 13d is rotated on the seat 13b2 to make a virtual straight line connecting the foot portions 13d3, 13d4 orthogonal to inclination direction of the first objective lens 12a. The inclination direction of the first objective lens 12a is a direction along a diameter connecting the highest point and the lowest point in the circular edge of the first objective lens 12a. Next the spacer 13d is tilted by α in clockwise direction with making the foot portions 13d3, 13d4 touching the seat 13d2 work as fulcrums. Therefore the spacer 13d can be tilted to make the inclination angle of the second objective lens 12b substantially parallel to that of the first objective lens 12a. In this state, the spacer 13d is fixed to second lens housing portion 13b by an adhesion bond. This leads that the second objective lens 12b is fixed at the inclination angle same as that of the first objective lens 12a.
As described above, according to the optical pickup device 10 of this embodiment, the second objective lens 12b can be adjusted its rotation angle by rotating the spacer 13d along the second opening 13b1 and adjusted its inclination angle by tilting the spacer 13d by making the foot portions 13d3, 13d4 work as fulcrums. High machining accuracy for making the lens holder 13 is not required, because geometrical variations of the lens housing portions 13a, 13b can be absorbed by tilting and rotating of the spacer 13d. Therefore the lens holder 13 can be made from even resin whose machining accuracy is worse than metal. And the lens holder 13 can be light because the lens holder 13 is made from the resin. Therefore, unwanted vibration of the lens holder 13 can be reduced.
Optical pickup device of the second embodiment realizing the present invention will be explained below.
As described above, according to the optical pickup device 10 of this embodiment, advantages same as that of the first embodiment can be obtained, further another advantage described below can be obtained. That is, the shape of the spacer 13d is simple and easy-to-make because of the rectangular shaped foot portions 13d7, 13d8.
An object of the present invention is providing an optical pickup device and optical disc reading device using the optical pickup device that make adjustment angles of objective lenses easy without increasing weight of a lens holder.
To achieve the object, an optical pickup device of an aspect of the present invention is configured to be comprised of: a first objective lens focusing laser beam generated by a laser generator; a second objective lens focusing the laser beam with a focal length different from that of the first objective lens; a first lens housing portion having a first seat whereon the first objective lens is put; a second lens housing portion having a second seat that is substantially ring shape; a ring shaped spacer put on the second seat and holding the second objective lens; a couple of foot portions protruding to the second seat from radially opposite positions in the spacer.
According to the configuration mentioned above, the second objective lens is holed by the spacer is placed to the second lens housing portion by putting the spacer on the second seat of the second lens housing portion with the foot portions supported by the second seat. The objective lens can be adjusted its angle by rotating the spacer along to the opening and tilting the spacer by using the foot portions as fulcrums. High machining accuracy for making the second lens housing portion is not required, because geometrical variations of the second lens housing portion can be absorbed by tilting and rotating the spacer. Therefore the second lens housing portion can be made from even resin whose machining accuracy is worse than metal. And the second lens housing portion can be light because the second lens housing portion can be made from the resin. Therefore, unwanted vibration of the second lens housing portion can be reduced.
Another aspect of the present invention discloses an optical pickup device wherein: the second lens housing portion, the spacer and the second objective lens are concentrically arranged.
An optional aspect of the present invention discloses an optical pickup device wherein: each of the foot portions is substantially triangular shape.
Another aspect of the present invention discloses an optical pickup device as wherein: each of the foot portions is substantially rectangular shape.
Another aspect of the present invention discloses an optical pickup device wherein: the spacer, the first lens housing portion and the second lens housing portion are made from resin.
A concrete aspect of the present invention discloses an optical disc reading device comprising: a laser diode generating laser beam; a first objective lens focusing the laser beam generated by the laser diode and irradiating the laser beam to a recording surface of an optical disc; a second objective lens focusing the laser beam with a focal length different from that of the first objective lens and irradiating the laser beam to the recording surface of the optical disc; an optical system irradiating the laser beam from the laser diode to the first objective lens or second objective lens; a detector detecting the laser beam reflected by the recording surface of the optical disc and converting a result of the laser beam detecting to digital signals; a lens holder made from resin and formed substantially boxy shape with a upper plane receiving the laser beam; a first lens housing portion made from resin and formed substantially tubular shape with a first opening parallel to the upper plane and with a first seat whereon the first objective lens is put; a second lens housing portion made from resin and formed substantially tubular shape with a second opening parallel to the upper plane and with a second seat that is substantially ring shape; a ring shaped spacer made from resin concentrically put on the second seat and concentrically holding the second objective lens; a couple of triangular foot portions protruding to the second seat from radially opposite positions in the spacer and working as fulcrums for tilting the spacer to make the second objective lens parallel to the first objective lens.
Although the invention has been described in considerable detail in language specific to structural features or method acts, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as preferred forms of implementing the claimed invention. Therefore, while exemplary illustrative embodiments of the invention have been described, numerous variations and alternative embodiments will occur to those skilled in the art. Such variations and alternate embodiments are contemplated, and can be made without departing from the spirit and scope of the invention.
It is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
It should further be noted that throughout the entire disclosure, the labels such as left, right, front, back, top, bottom, forward, reverse, clockwise, counter clockwise, up, down, or other similar terms such as upper, lower, aft, fore, vertical, horizontal, proximal, distal, etc. have been used for convenience purposes only and are not intended to imply any particular fixed direction or orientation. Instead, they are used to reflect relative locations and/or directions/orientations between various portions of an object.
In addition, reference to “first,” “second,” “third,” and etc. members throughout the disclosure (and in particular, claims) is not used to show a serial or numerical limitation but instead is used to distinguish or identify the various members of the group.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2006-233646 | Aug 2006 | JP | national |
