JPH0546992A - Optical reproducing device - Google Patents

Abstract

PURPOSE:To obtain an inexpensive small-sized optical reproducing device with which information can be read at a high speed. CONSTITUTION:The optical system of this optical reproducing device is provided with a laser light source 10, collimator lens 11, and objective 12. The optical system is provided on an optical waveguide memory 13. An photodetecting section 14 is provided in parallel with and adjacent to the side face of the memory 13. The laser light emitted from the light source 10 is condensed to the end face of the memory 13 through the objective 12 after the light is transformed into parallel rays through the collimator lens 11. The part of the laser light made incident to the core section of the memory 13 is scattered by each information pit 22 and goes out from the side face of the memory 13. The scattered light rays are detected by means of the photodetecting section 14 provided with a plurality of detectors 30 and converted into electric signals. The electric signals are outputted as reproduced signals through an amplifier circuit 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reproducing device for reproducing information recorded in an optical waveguide memory.

[0002]

2. Description of the Related Art In recent years, an optical recording / reproducing apparatus for optically recording / reproducing information such as code data, video information, audio information, etc. has been developed. In particular, an LD (laser disk) device for reproducing video information is used. A CD (Compact Disc) device for reproducing audio information is widely used.

On an optical disk used in this type of apparatus, video information is FM-modulated and then recorded as unevenness of pits corresponding to a modulation signal, and an audio signal is converted into a digital signal, which is suitable for recording. After being modulated into a signal, it is recorded as unevenness of pits corresponding to the modulated signal.

FIG. 5 shows an example of an optical disc. The optical disc shown in the figure is a part of which is cut away for ease of explanation. Further, FIG. 6 shows an enlarged view of portion B in FIG.

A large number of information pits are formed on the disk substrate 80.
81 are arranged in the circumferential direction. When reading information from this optical disc, a focused spot of laser light is applied onto the disc and traced along the information track of the disc. The intensity of the reflected light from the disc during this trace changes depending on the presence or absence of the information pit 81.
Therefore, the recorded information can be reproduced by detecting the change in the light intensity with the detector.

FIG. 7 shows a concrete example of an optical reproducing apparatus using this type of optical disk. The optical disc 77 is a CAV (Consta
nt Angular Velocity method or CLV (Co
It is rotated by a spindle motor 78 based on the nst-ant Linear Velocity (constant linear velocity) method. The laser light emitted from the laser light source 70 is collimated by the collimator lens 71, reflected by the half prism 72, and focused on the optical disc 77 by the objective lens 73. Next, the laser light is reflected by the optical disk 77 and then converted into parallel light by the objective lens 73, passes through the half prism 72, and is detected.
Up to 74. The output signal of the detector 74 is amplified by the amplifier 75 and output from the terminal 76 as a reproduction signal. This reproduction signal is further demodulated by a demodulator into a video signal or an audio signal. In this type of optical regenerator, one to three light beams are usually used, but only one of them is used for information detection.

[0007]

In recent years, the development of a video signal digitizing device has been advanced from the viewpoint of high image quality. When digitizing a video signal (NTSC signal), the sampling frequency is 14.3 MHz (4 fse
If c) and the number of quantization bits is 8 bits, the required transfer rate is 114 Mbit / sec. Current L
When digital recording is performed by the D device, the obtained transfer rate is about 20 Mbit / sec. Therefore, LD
In order to digitally record a video signal, the video signal is band-compressed to reduce the amount of information, or the LD player is multi-beamed and information is read using a plurality of light beams for reading information. It is necessary to increase the read rate.

However, a dedicated processor is required to perform the band compression of the video signal, and the processing speed is
High throughput is required for both throughput. Therefore, there is a problem that the system becomes large and the cost also increases. In addition, when the multi-beam is used, the structure of the player becomes complicated and the recording time is shortened.

Therefore, the present invention solves the above problems,
The present invention provides a small-sized and low-cost optical reproducing device capable of reading information at high speed.

[0010]

According to the present invention, a plurality of detectors for respectively detecting a plurality of scattered lights scattered from each information pit of an optical waveguide memory of a light beam incident on the optical waveguide memory. Also provided is an optical reproducing device including a reproducing unit that collectively reproduces information recorded in the optical waveguide memory based on a plurality of detection signals output from the detector in response to scattered light.

[0011]

A light beam is incident on a light guide memory, which is a medium for recording information, by a light source, and a plurality of detectors are used to
A plurality of scattered lights from the information pits of the optical waveguide memory at positions corresponding to the detectors are respectively received, and as a result, a plurality of detection signals responsive to these scattered lights are output. Next, the reproducing means simultaneously performs processing such as amplification on all the detection signals of the plurality of detectors, and the information recorded in the optical waveguide memory is collectively read.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of an optical reproducing apparatus according to the present invention, and FIG. 2 is a sectional view of FIG.

The optical waveguide memory 13 used in the optical reproducing apparatus according to the present embodiment is provided in a tape shape, and information is recorded in the core portion of the optical waveguide memory 13 with or without the information pits 22. That is, the presence or absence of the refractive index discontinuity portion is arranged in the core portion of the optical waveguide memory 13 according to the information to be recorded.

The optical system of the light reproducing device comprises a laser light source 10, a collimator lens 11 and an objective lens 12. This optical system includes an objective lens 12, a collimator lens 11 and a laser light source on top of the optical waveguide memory 13 from the side closer to the memory.
It is installed in the order of 10. Further, a photodetecting section 14 is arranged adjacent to the side surface of the optical waveguide memory 13 and in parallel with the side surface of the optical waveguide memory 13.

A plurality of (n) detectors 30 constituting the photodetecting section 14 are arranged in a linear array, and an amplifier (not shown in FIGS. 1 and 2) is used for each detector. And the amplifier circuits 31 are connected to each other. In the detector 30, a plurality of pin photodiodes are linearly arranged.

The laser light emitted from the laser light source 10 is collimated by the collimator lens 11 and focused on the upper end surface of the optical waveguide memory 13 by the objective lens 12. As shown in FIG. 2, the optical waveguide memory 13 is configured by sandwiching a core portion 21 between two clad portions 20, and an information pit 22 is formed in the core portion 21. The laser light focused by the objective lens 12 enters the core portion 21. The incident laser light travels in the direction of arrow A in the core portion 21, part of the laser light is scattered at the information pit 22, and scattered light 23 goes out from the side surface of the optical waveguide memory 13. Further, the laser light travels inside the core portion 20, and subsequently scattered light 23 is generated at the portion where the information pit 22 exists.

The scattered light emitted from the side surface of the optical waveguide memory 13 to the outside is detected by the photo-detecting section 14 having n detectors 30, converted into a voltage signal, and then passed through the amplifier circuit 31 to obtain a reproduction signal. Is output from the terminal 32. An amplifier (not shown in FIGS. 1 and 2) is connected to each detector 30,
This amplifier converts the current signal from the detector 30 into a voltage signal. In the figure, only one system is shown for the amplifier 31 and the terminal 32, but in reality, there are n systems equal to the number of the detectors 30. The n-system amplifier circuit 31 and the terminal 32 correspond to the reproducing means of the present invention.

The above-mentioned tape-shaped optical waveguide memory 13 in this embodiment is constructed so as to move in the direction of the arrow in FIG. 1, so that the laser light is sequentially incident on the core portion of the optical waveguide memory 13, The laser light is scattered by each information pit, the information pit is detected by this, and the information is collectively read.

FIG. 3 shows the details of an example of the photo-detecting section 14.

The current signal output from each of the detectors 30 arranged in a linear array is converted into a voltage signal by the amplifier 33 and output to the amplifier circuit 31. The voltage signal is amplified by the amplifier circuit 31, and then output from the terminal 32.

In the optical reproducing apparatus according to the present embodiment, a plurality of scattered lights scattered from each information pit are detected by the detector 30 at the corresponding position, and the detection signals are amplified by the amplifier circuits 31 and 31 of a plurality of systems. Since it is output as a reproduction signal by the reproduction means including the terminal 32, a plurality of pieces of digital information can be collectively read. The number of channels of signals that can be reproduced collectively is the same as the number of detectors 30, and therefore,
By increasing the number of detectors 30, the information read rate can be greatly improved. In addition, since one light beam is used in this embodiment, it is possible to provide a small-sized and low-cost optical reproducing device.

Furthermore, by temporarily storing the reproduction signal output from the terminal 32 in the buffer and reading it as needed, it is possible to continuously reproduce the signal at a constant rate.

Next, another embodiment will be described with reference to the drawings.

Similar to the first embodiment, the optical waveguide memory 13 used in the optical reproducing device is provided in a tape shape.
Similarly, the optical system of the optical reproducing device also includes a laser light source 10, a collimator lens 11, and an objective lens 12, and this optical system is installed above the optical waveguide memory 13. Further, a photodetection unit 15 is arranged adjacent to the side surface of the optical waveguide memory 13 and in parallel with the side surface of the optical waveguide memory 13.

FIG. 4 shows a plan view of the photo-detecting section 15 according to this embodiment. In the first embodiment described above, the detectors are arranged in a linear array, but in the present embodiment, the detectors 34 are arranged in a matrix, and these detectors 34 form each information pit of the optical waveguide memory. The scattered light from is detected.

The photodetection section 15 is composed of 4n detectors 34 arranged in a matrix of n in the vertical direction and four in the horizontal direction, and the current signal from each detector 34 is connected to the detector. It is converted into a voltage signal by the same number of amplifiers 37, amplified by the amplifier circuit 35, and then output from the terminal 36. The detector has pin photodiodes arranged in a matrix. Although only one system is shown for the amplifier 35 and the terminal 36 in the figure, there are actually 4n systems, which is equal to the number of detectors 34. This 4n system amplifier circuit 35 and terminal 36
Corresponds to the reproducing means of the present invention.

In the optical reproducing apparatus according to the second embodiment described above, a plurality of scattered lights scattered from each information pit are detected by the detectors 34 at corresponding positions, and the detection signals are of a plurality of systems. Since it is output as a reproduction signal by the reproduction means composed of the amplifier circuit 35 and the terminal 36, a plurality of digital information can be read at once. The number of channels of signals that can be collectively reproduced is the same as the number of detectors 34, and this number is larger than that in the first embodiment. Therefore, in the second embodiment, the information read rate can be greatly improved as compared with the first embodiment. Further, since one light beam is used as in the first embodiment, it is possible to provide a small-sized and low-cost optical reproducing device.

In the above embodiment, the optical system is installed above the optical waveguide memory and the photodetector is located laterally of the optical waveguide memory. However, the optical system and the photodetector are installed at different locations depending on the optical waveguide memory. It should be arranged. Also, although a pin photodiode was used as the detector as a whole, instead of this, another type of detector having equivalent performance, for example, C
A CD or the like may be used.

Further, in the second embodiment, the photodetector
Although 16 is composed of 4n detectors, the number of detectors in the vertical and horizontal directions and the total number of detectors are not limited to this.

[0031]

The optical reproducing apparatus according to the present invention receives a plurality of scattered light from each information pit of the optical waveguide memory, outputs a electric signal in response to the plurality of detectors, and responds to the scattered light. Since it has a reproducing means for collectively reproducing the information recorded in the optical waveguide memory based on a plurality of detection signals output from the detector, it is possible to collectively read the plurality of recorded information. In addition, a reproduction signal can be obtained at high speed. Therefore, it is possible to realize an optical reproducing apparatus that collectively reads information at high speed, and it is also possible to realize a large-capacity, high-transfer-rate reproducing system compatible with high-definition images such as a future high-definition system.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of an optical reproducing apparatus according to the present invention.

2 is a cross-sectional view of the optical reproducing device of FIG.

FIG. 3 is a detailed configuration diagram of a photodetector unit that constitutes the optical reproduction device in FIG.

FIG. 4 is a configuration diagram of a photodetector section of another embodiment of the optical reproducing apparatus according to the present invention.

FIG. 5 is a perspective view of an optical disc used in a conventional optical reproducing device.

FIG. 6 is an enlarged view of a part of the optical disc of FIG.

FIG. 7 is a block diagram of an example of a conventional optical reproducing device.

[Explanation of symbols]

 10 Laser light source 11 Collimator lens 12 Objective lens 13 Optical waveguide memory 14, 15 Photodetector section 20 Cladding section 21 Core section 22 Information pit 30, 34 Detector 31, 35 Amplifier circuit 32, 36 Terminal 33, 37 Amplifier

Claims (1)

[Claims] 1. A plurality of detectors for respectively detecting a plurality of scattered lights scattered from each information pit of the optical waveguide memory of a light beam incident on the optical waveguide memory, and in response to the scattered light. An optical reproducing apparatus comprising: a reproducing unit that collectively reproduces information recorded in the optical waveguide memory based on a plurality of detection signals output from the detector.