Optical recording apparatus and optical head
View Patent ↗To provide an optical recording apparatus capable of effectively suppressing useless fixation to an information-unrecorded area during a fixing process with a simple structure, and an optical head. Upon recording information, a movable lens of an expander lens 104 is positioned in an information recording position. In an information fixing process, the movable lens of the expander lens 104 is positioned in a fixing-process position. In this case, a range of irradiation to the recording medium with the data light becomes somewhat wider than that in the information recording process. Accordingly, it is possible to fix the information to an area irradiated with the data light in the information recording process without fail. In addition, the irradiation range is only somewhat wider than that in the information fixing process, making it possible to minimize the region uselessly subjected to the fixing process.
1. An optical recording apparatus for recording information by causing data light and reference light to interfere with each other inside a hologram material layer, characterized by comprising:
means for providing data light and reference light for recording information inside the hologram material layer;
an optical element for changing a range of irradiation to the hologram material layer with the data light;
means for suspending the irradiation to the hologram material layer with the reference light for the fixing of the information;
a driving unit for driving the optical element; and
a control unit for controlling the driving unit such that the range of irradiation to the hologram material layer with the data light is wider during fixing the information than the range during recording the information.
2. The optical recording apparatus according to claim 1 , characterized in that the optical element comprises an expander lens that is driven by the driving unit to change a diffusion state of the data light.
3. The optical recording apparatus according to claim 1 , characterized in that the optical element comprises a diffuser that is driven by the driving unit to change a diffusion state of the data light and a coherent state.
4. The optical recording apparatus according to any one of claims 1 to 3 , characterized in that the control unit controls the driving unit such that the range of irradiation to the hologram material layer with the data light is switched from the range in recording the information to the range in fixing the information upon completion of information recording for one recording area.
5. The optical recording apparatus according to any one of claims 1 to 3 , characterized in that the control unit controls the driving unit such that the range of irradiation to the hologram material layer with the data light is switched from the range in recording the information to the range in fixing the information along with shift in irradiation position of the data light to a recording area where information recording starts out of a plurality of recording areas that have been subjected to the information recording in succession.
6. The optical recording apparatus according to claim 5 , characterized in that the data light is applied with the range of irradiation to the hologram material layer being set to the range in fixing the information while successively shifting its irradiation position from the recording area where the information recording starts toward a recording area where the information recording ends.
7. The optical recording apparatus according to any one of claims 1 to 3 , characterized in that the control unit controls the driving unit such that the range of irradiation to the hologram material layer with the data light is switched from the range in recording the information to the range in fixing the information upon completion of information recording for a recording area where information recording ends out of a plurality of recording areas that have been subjected to the information recording in succession.
8. The optical recording apparatus according to claim 7 , characterized in that the data light is applied with the range of irradiation to the hologram material layer being set to the range in fixing the information while successively shifting its irradiation position from the recording area where the information recording ends toward a recording area where the information recording starts.
9. The optical recording apparatus according to any one of claims 1 to 3 , characterized by further comprising means for temporally changing the coherent state of the data light in the hologram material layer in fixing the information.
10. The optical recording apparatus according to claim 9 , characterized in that the means for temporally changing the coherent state of the data light comprises means for repeatedly displacing the data light in a direction of an optical axis of the data light or a direction perpendicular to the optical axis in fixing the information.
11. The optical recording apparatus according to claim 9 , characterized in that the means for temporally changing the coherent state of the data light comprises means for periodically changing a drive current of a semiconductor laser for emitting the laser beam in fixing the information.
12. The optical recording apparatus according to claim 9 , characterized in that the means for temporally changing the coherent state of the data light comprises means for periodically changing a temperature of a semiconductor laser for emitting the laser beam in fixing the information.
13. An optical head for irradiating a hologram material layer with data light and reference light to recording information, characterized by comprising:
means for providing data light and reference light for recording information inside the hologram material layer;
an optical element inserted in an optical path for the data light and adapted to change a range of irradiation to the hologram material layer with the data light;
means for suspending the irradiation to the hologram material layer with the reference light for the fixing of the information; and
driving unit for driving the optical element to set the optical element to ( 1 ) a first position for recording information in the hologram material layer and ( 2 ) a second position for fixing the recorded information, in order to change the range of irradiation to the hologram material layer.
14. The optical head according to claim 13 , characterized in that the optical element comprises an expander lens that is driven by the driving unit to change a diffusion state of the data light.
15. The optical head according to claim 13 , characterized in that the optical element comprises a diffuser that is driven by the driving unit to change a diffusion state of the data light and a coherent state.