JPS60173724A - Optical information reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information reproducing apparatus used for video discs, digital audio discs, and the like.

2. Description of the Related Art As a conventional optical information reproducing apparatus of this type, for example, those shown in FIGS. 1 to 3 are known. In other words, the reference numeral 1 in Figure 1 is a light source, for example, a semiconductor laser, and the laser beam emitted from the semiconductor laser 1 is converted into a parallel beam by a collimator lens 2, and then passes through a polarizing beam splitter 3, which is a separating optical system. The light is then converted into a circularly polarized beam by the quarter-wave plate 4. Thereafter, the beam 8 is focused by the objective lens 5 onto the pit 6a of the optical disk 6 as shown in FIG. The collimator lens 2, quarter wavelength plate 4, objective lens 5, etc. of such an optical system are particularly referred to as a focusing optical system. Then, the beam 8 is reflected by the optical disk 6, and the read beam 9, which is this reflected light, follows the optical path opposite to the incident light, passes through the objective lens 5, and reaches the quarter-wave plate 4, where the circularly polarized light becomes linearly polarized light. be changed. However, this time, the linearly polarized light is orthogonal to the incident light, and is reflected by the polarizing beam splitter 3 and enters the photoelectric conversion element 11 via the focus detection optical system IO.

This photoelectric conversion element 11 is as shown in FIG.

It is equipped with a four-division light-receiving surface 12 consisting of four division surfaces 12a, 12b, 12c, 1'2d, and this four-division light-receiving surface 1
The reading beam 9 is received by the photoelectric conversion element 11, and the signal detection circuit 13 connected to the photoelectric conversion element 11 detects a track error (hereinafter referred to as rTEJ) signal, a focus error (hereinafter referred to as rFHJ) signal, and an information reproduction (hereinafter referred to as rFHJ) signal. rRFJ) signal is detected. In other words, the dividing surfaces 12a, 12c
The output of the electrical signal converted from the optical signal is sent to the first adder 1.
4, and the outputs of the electrical signals from the dividing surfaces 12b and 12d are added together in the second adder 15. and.

The outputs from the re-adders 14 and 15 are subtracted by a subtracter 16, and an FE multiplied signal is obtained from an output terminal 17. Further, the sum of the outputs from all the dividing surfaces 12a...12d is added to the third adder 18.
is calculated and an RF multiplied signal is obtained from the output terminal 19, and the sum of the outputs is further differentiated with respect to time by a differentiating circuit 20, and this value and the output value from the subtracter 16 (divided light receiving surface 12a
.

12c and the difference between the outputs from the divided light-receiving surfaces 12b and 12d) are multiplied by the multiplier 21 and output from the output end 22 to T.
An E-fold signal is obtained.

The output terminal 17 and the output terminal 22 are respectively connected to a focus servo circuit and a 1-racking servo circuit (not shown), and outputs from these circuits operate actuators to perform tracking servo and focus servo. Further, the output end 19 is connected to a signal processing circuit (not shown), and the information on the optical disc 6 is reproduced by this signal processing circuit.

However, in such a conventional optical information reproducing device, the beam 8 is irradiated onto a single track, so when making trick play jumps, etc., the device itself is optically demistrated. It is necessary to irradiate the beam 8 onto different tracks by moving the beam 8 in the radial direction of the beam 6. Therefore, there is a limit to how high the speed of trick play can be achieved. Furthermore, as a matter of course, information from different tracks could not be played back at the same time.

This invention was made in view of the conventional situation,
It is an object of the present invention to provide an optical information reproducing device that speeds up trick play by making it possible to instantly perform jumps in trick play, and that also enables simultaneous reproduction of information on different tracks. It is said that

In order to achieve such an object, the optical information reproducing device of the present invention includes a light source, a focusing optical system that focuses the light beam emitted from the light source onto an optical disk, and a focusing optical system provided on the optical path of the focusing optical system. a separation optical system that separates the reflected light, which becomes an optical signal reflected from the optical disk, from the optical path; and a focus detection system that detects the focused state on the optical disk when the reflected light separated by this separation optical system is incident. The reflected light that has passed through the optical system and the focus detection optical system is incident on the optical system, and the photoelectric conversion element converts the optical signal into an electrical signal.The electrical signal from the photoelectric conversion element is input and processed to reproduce information and perform various functions. The focusing optical system includes a diffraction grating that separates the light beam from the light source so as to irradiate one beam on each of at least two tracks of the optical disk. , is provided between the light source and the separation optical system, and on the other hand, the photoelectric conversion element is provided with at least two light receiving sections each having a four-part light receiving surface that receives each of the reflected lights reflected from each track. It is characterized by the presence of

The present invention will be explained below based on the drawings. In this description, the same reference numerals will be used for parts or members that are the same as or equivalent to those in the prior art, and redundant description will be omitted.

FIGS. 4 to 6 are diagrams showing an embodiment of the present invention.

First, to explain the configuration, reference numeral 1 in the figure is a semiconductor laser, 2
3 is a collimator lens, and 3 is a polarizing beam splitter. Between the polarizing beam splitter 3 and the collimator lens 2, a diffraction grating 24, which is a part of the focusing optical system, is disposed.

This diffraction grating 24 has an optical grating surface 24a that separates the light beam from the semiconductor laser 1 into three beams, and the separated beams 26, 27, and 28 are transmitted to the optical disc 6 as shown in FIG.
The beam is arranged so that the three racks 1 to A, B, and C are irradiated with the beam.

On the other hand, as shown in FIG. 6, the photoelectric conversion element 29 has a four-part light-receiving surface 33 so as to receive the three reading beams 30, 31, and 32 reflected from the respective tracks A, B, and C. , 34.35.

There are nine U's.

The light receiving sections S, T, and U of the photoelectric conversion element 29 are connected to circuits that perform information reproduction and various servo operations, as described below. Namely.

First, each of the light receiving sections S, T, and U is connected to signal detection circuits 36, 37, and 38 for detecting TE, FE, and RF multiplied signals, respectively. Each of these signal detection circuits 36, 37.3
Reference numeral 8 has the same structure as the conventional example shown in FIG. 3, and includes a subtracter, an adder, a differentiation circuit, a multiplier, etc., although not shown. In addition, the signal detection circuits 3 on both sides in FIG.
Attenuators 3.9 and 40 are connected to each output terminal 41.6 and 38, respectively. , 42.43, it is possible to obtain 1.E, 1.E and RF multiplied signals. Note that the attenuators 39 and 40 can also be arranged between the light receiving sections S and U and the signal detection circuits 36 and 38, respectively. These output terminals 41, 42, 43 side, that is, each signal detection circuit 3G,
37. On the output side of 38, the signal detection circuit 36, 3 of
A switch X is provided to select and take out the output from 7.38. The common terminal 45 of this switch
is connected to the servo/RF forming circuit 46, and this servo/RF formation circuit 46
The servo circuit of the RF forming circuit 46 becomes the actuator 47.

The RF forming circuits are each connected to the signal processing circuit 48.

Next, the operation of the optical information reproducing device having such a configuration will be explained. When laser light is emitted from the semiconductor laser 1, it is converted into a parallel beam by the collimator lens 2.

Thereafter, this laser light is transmitted to the optical grating surface 2 of the diffraction grating 24.
The beam is separated into three beams at 4a and passes through a polarizing beam splitter 3, a quarter-wave plate 4, and an objective lens 5, and as shown in FIG.

Beams 26, 27, and 28 are irradiated on the beams 26, 27, and 28, respectively.

Thereafter, it is reflected by the optical disk 6, passes through the objective lens 5 and the quarter-wave plate 4 again, and passes through the polarizing beam splitter 3.
and passes through the focus detection optical system 10 to the four-divided light-receiving surfaces 33, 34, 3 of the light-receiving parts S, T, and U of the photoelectric conversion element 29.
6. The light is received at each of the 5 and 5 as shown in FIG. In this state, when the movable contact Y of the switch X, for example, is connected to the output end 42, the optical signal of the reading beam 31 received by the four-part light-receiving surface 34 is converted into an electrical signal. Then, the signal detection circuit 37 detects the TE, FE, and RF multiplied signals in the same manner as in the past, and this output is input to the servo/RF forming circuit 46, and the output from the servo circuit of this servo/RF forming circuit 46 drives the actuator 47. is driven, tracking servo is performed to accurately trace track B, and focus servo is performed to focus on pit 6a. On the other hand, the RF of the servo/RF forming circuit 46
The output from the forming circuit is input to the signal processing circuit 4B, and this signal processing circuit 48 reproduces the information on track B of the optical disc 6.

By the way, in order to perform a trick play jump from the above state, rotate the movable contact Y of the switch X and connect it to the output end 41 or 43.
As a result, various servos and information reproduction on track A or 1-rack C are performed in the same manner as described above.

Therefore, by simply operating the switch X, the jump operation can be easily and instantaneously performed.

Since such a device separates one beam into many parts using the diffraction grating 24, the light intensity of the reading beams 30 and 32 received by the light receiving sections S and U and the reading beams 30 and 32 received by the light receiving section T are different. The light intensity of the beam 31 will be different. Therefore, by providing the attenuators 39 and 40, the output from the output end 42 of the light receiving section T and the output end 41 of the light receiving section S and U are adjusted.
Which light receiving part S+,
Even if T or U is selected, accurate servo or information reproduction is performed.

On the other hand, for example, a configuration different from the above conventional example, that is, a TIE・F
The servo circuit that inputs the IE signal is connected to each signal detection circuit 36.
, 37 and 38, the RF multiplied signal is input to each of I
'Connect the IF formation circuit. Then, the TE-FE multiplied signal can be taken out from any of the light receiving sections S, T, and U, and the RF multiplied signal can also be taken out from all the light receiving sections S, T, and U at the same time.

In this way, it becomes possible to simultaneously reproduce information on tracks A, B, and C of the optical disc 6. Even in this case,
By connecting attenuators between the light receiving sections S and U and the corresponding two IIF forming circuits, the same advantages as in the above embodiment can be obtained.

Further, FIG. 7 shows another embodiment of the present invention.

In this embodiment, a collimator lens 2 is disposed between a polarizing beam splitter 3 and a quarter-wave plate 4, and a diffraction grating 2
4 is arranged between the semiconductor laser 1 and the polarizing beam splitter 3. Even in this case, the same effect as in the above embodiment can be obtained. The other configurations are also similar to those of the previous embodiment.

As in both of the above embodiments, the diffraction grating 24 can be placed at any position between the semiconductor laser 1 and the polarizing beam splitter 3.

In both of the above embodiments, the beam is separated into three beams by the diffraction grating 24 and irradiated onto the three tracks A, B, and C. 4
Of course, it is also possible to irradiate a track such as a book. In this case, two or four light receiving sections of the photoelectric conversion element are provided.

As explained above, according to the present invention, it is possible to instantly and easily jump between different tracks on an optical disc without moving the optical information reproducing device, thereby speeding up trick play. It also becomes possible to simultaneously reproduce information from multiple tracks.

[Brief explanation of drawings]

1 to 3 are diagrams showing a conventional optical information reproducing device, in which FIG. 1 is a schematic diagram of the device, FIG. 2 is a diagram showing a state of beam irradiation onto an optical disk, and FIG. 3 is a diagram showing a conventional optical information reproducing device. Figures 4 to 6 are diagrams showing signal detection circuits connected to photoelectric conversion elements.
The figures show an embodiment of the optical information reproducing device of the present invention. FIG. 4 is a schematic diagram of the device, FIG. 5 is a diagram corresponding to FIG. 2, and FIG. 6 is a part of the device. The block diagram shown in FIG. 7 is a diagram corresponding to FIG. 4 showing another embodiment. ■...Semiconductor laser (light source). 2... Collimator lens 3... Polarizing beam splitter (separation optical system), 10.
... Focus detection optical system, 29... Photoelectric conversion element, S, T
, U... Light receiving section, 33, 34.35... 4-split light receiving surface, 36.37.38... Signal detection circuit, 39.40
...Attenuator, X...Switch, 46...
Servo/RF formation circuit, 47... actuator, 4
8... Signal processing circuit, 6... Optical disk, A, [
1,C...1) Rack. Figure 1 Figure 3 Figure 1; -13 911''; Figure 4 Figure 5 Figure 6

Claims (5)

[Claims] (1) a light source; a focusing optical system that focuses the light flux emitted from the light source onto an optical disk; and a focusing optical system that is provided on the optical path of the focusing optical system, and which produces an optical signal reflected from the optical disk. a separation optical system that separates reflected light from the optical path; a focus detection optical system that receives the reflected light separated by the separation optical system and detects a focused state on the optical disk; and a focus detection optical system that detects a focused state on the optical disk. It has a photoelectric conversion element on which the reflected light that has passed is incident and converts the optical signal into an electric signal, and a circuit that inputs and processes the electric signal from the photoelectric conversion element and performs information reproduction and various servos, The focusing optical system includes a diffraction grating that separates the light beam from the light source so as to irradiate each of at least two tracks of the optical disk with one beam.
At least two light-receiving surfaces are provided between the light source and the separation optical system, and the photoelectric conversion element includes at least two light-receiving surfaces that receive each of the reflected lights from each of the racks.
What is claimed is: 1. An optical information reproducing device comprising two light receiving sections. (2) The circuit includes a signal detection circuit that is connected to each of the light receiving sections and detects various servo signals and information reproduction signals by inputting electrical signals from the light receiving section, and a signal detection circuit that is connected to each of the light receiving sections and detects various servo signals and information reproduction signals; Claim 1, characterized in that the device comprises a switch connected to the circuit for selecting and extracting an output from an arbitrary signal detection circuit, and a servo/+iF forming circuit connected to the output side of the switch. optical information reproducing device. (3) The optical information reproducing method according to claim 2, wherein the circuit has an attenuator between the predetermined light receiving section and the switch to make the output from each signal detection circuit the same level. Device. (4) The circuit is connected to the output side of any signal detection circuit, such as a signal detection circuit that is connected to each light receiving section and inputs the electric signal from the light receiving section to detect various servo signals and information reproduction signals. a servo circuit that is connected to input various servo signals, and a servo circuit that is connected to each of the signal detection circuits;
2. The optical information reproducing apparatus according to claim 1, further comprising an RF forming circuit into which an information reproducing signal is input. (5) A circuit is connected between a predetermined light receiving section and an RF forming circuit.
5. The optical information reproducing apparatus according to claim 4, further comprising an attenuator that makes the outputs from each signal detection circuit the same level.