JPS6048055B2 - search device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a search device for searching and reproducing a portion of a signal recorded concentrically or spirally on a disc-shaped record carrier (hereinafter referred to as a recording disc). do.

If the recording disk is optically recorded, the recording density of signals on the recording disk is extremely high.

For example, on a recording disk with a diameter of 30 cm, one concentric circle has one
If image information of frames is to be recorded, image information of tens of thousands of frames can be recorded. When attempting to search for and reproduce a desired single frame of image information from tens of thousands of frames of image information, it is extremely difficult to obtain the desired single frame of image information without some sort of search function. Furthermore, when recording music in a spiral manner on the aforementioned recording disk, several dozen pieces of music cannot be recorded. Even when such a large amount of music is recorded on a recording disk, it is very inconvenient if the music cannot be found. As mentioned above, an object of the present invention is to provide a search device that searches and reproduces desired information at high density and at high speed from among information recorded on a recording disk in a high density concentric or spiral manner. It is to provide.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a retrieval device according to an embodiment of the present invention for optically retrieving and reproducing information on a recording disk. 1 is a light source such as a He-Ne laser, 2 is a light beam generated from the light source 1, 3 is a recording disk, and 4 is a pickup device for reproducing information on the recording disk 3.

The pickup device 4 includes an intermediate lens 5, a total reflection mirror 6 for changing the direction of the light beam 2 generated from the light source 1, a converging lens 7 for converging the light beam 2 onto the recording disk 3,
A semitransparent mirror 8 for separating the reflected light from the recording disk 3 of the light beam 2, and a two-split mirror for converting the information on the recording disk 33 into an electrical signal from the reflected light separated by the semitransparent mirror 8. It is composed of a photodetector 9. Reference numeral 10 denotes an electric motor for rotating the recording disk 3; 11 receives information signals on the recording disk 3 and signals across the information tracks from the photodetector 9; A movement detection circuit that generates pulses according to the relative amount of movement and also detects the direction of movement; 12 is an input device for inputting an address corresponding to desired information; 13 is an information signal output from photodetector 9; , an address reading circuit 14 reads the address of the information currently being reproduced; 14 is an up/down counter 1 which reads the address of the information currently being reproduced;
5 is an arithmetic device that calculates a preset value of 5.

The up/down counter 15 is operated by signals related to the amount of movement and the direction of movement from the movement detection circuit 11, and its output is converted into an analog signal by the DA converter 16. Reference numeral 17 denotes a drive circuit operated by the analog signal, and its output drives an O drive element 18 to move the pickup device 4 in the direction of an arrow 19 to retrieve desired information.

The driving element 18 is, for example, a DC motor or a linear motor. FIG. 2 is an explanatory diagram of the recording disk 3.

Reference numeral 20 indicates recording tracks recorded in a pentacentric manner.

In each recording track 20, one frame of image information is stored, and a search address and a corresponding search address are also recorded. When the number of tracks that can be recorded on the recording disk 3 is N, the outermost recording track is set to address 1, and the recording tracks are sequentially numbered 2, 3, 4, etc. toward the inner circumference, and the innermost recording track is set to address 1. Let the track be number N. These addresses are converted into binary and recorded on the recording disk 3. Let M be the number of bits required for binary conversion of N. Therefore, when recording a recording track address on the recording disk 3, a minimum of M persons are required. There are various recording methods to prevent misreading due to noise or dropouts, but since they are not directly related to the present invention, detailed description thereof will be omitted. In other words, the recording track address recorded on the recording disk 3 can be reproduced by the address reading circuit 13 by receiving the reflected light of the light beam 2 on the recording disk 3 by the photodetector 9. Next, when the pickup device 4 moves, the reflected light of the light beam 2 on the recording disk 3 generates a signal indicating that the light beam 2 has crossed the recording track 20 on the recording disk 3 and a signal indicating the direction of movement of the pickup device 4. Signal detection will be explained.

In FIG. 3, the two-split photodetector 9 is a photodetector 9a,
It is composed of a photodetector 9b. 21 is a beam spot when the reflected light of the light beam 2 on the recording disk 3 is irradiated onto the photodetector 9; 22 is the reflection at the unrecorded part between the recording tracks on the recording disk 3; The light 23 is the light emitted from the recording track 20 on the recording disk 3, and the beam spot 21 is made up of the reflected light 22 and the reflected light 23.

24 is a summation circuit for obtaining a composite signal of the outputs of the photodetectors 9a and 9b, and 25 is a difference circuit for obtaining the difference between the outputs of the photodetectors 9a and 9b.

FIG. 4 shows a recording track 20 on a recording disk 3 with a light beam 2.
There is one that shows the state where the two cross.

When the pickup device 4 moves from the outer circumference to the inner circumference of the recording disk 3, the light beam spot 21 on the photodetector 9
Assuming that the states traverse one recording track 20 in the order of A, b, c, d, when the pickup device 4 moves from the inner circumference to the outer circumference of the recording disk 3, the states D,
One recording track 20 is traversed in the order c, b, a. This will be explained with reference to FIG.

Waveform e is the output of the summation circuit 24 when the light beam 2 crosses the recording track 20. Difference circuit 25 when the pickup device 4 moves from the outer circumference to the inner circumference of the recording disk 3
Assuming that the output waveform of is waveform f, the output waveform of the difference circuit 25 when the pickup device 4 moves from the inner circumference to the outer circumference of the recording disk 3 is waveform g. In other words, the output of the sum circuit 24 does not differ depending on the moving direction of the pickup device 4, but the output of the difference circuit 25 differs when the pickup device 4 moves from the inner circumference to the outer circumference of the recording disk 3, and when the pickup device 4 moves from the outer circumference to the inner circumference. The phase is reversed with Yanghe, which moves toward . How these signals are processed in a circuit will be explained with reference to FIG.

For the sake of explanation, it is assumed that the up/down counter 15 counts the rising edge of an input pulse, and the up/down counter operates depending on the level of the input voltage. The output of the sum circuit 24 is input to the input 1 terminal, and the output of the difference circuit 25 is input to the input 2 terminal.
26, , is a detection circuit, 27 is a Schmitt gate circuit, 2
T3 is a differentiation circuit, 29 is a waveform shaping circuit, 30 is a rectification circuit, 31 is an inversion circuit, 32 is a waveform shaping circuit, 33 is a rectification circuit, 34 is an M circuit, 35 is an inversion circuit, 36 is an AND circuit, 37 is a It is a flip-flop circuit.

The output waveforms of these circuits will be explained with reference to FIG. The waveform k indicates that the light beam 2 tracks the recording track 20 on the recording disk 3.
It shows the skewer force waveform of the sum circuit 24 when the main line is crossed. The direction of movement of the pickup device 4 when it crosses the first two recording circles among these five recording circles is opposite to the direction of movement of the pickup device 4 when it crosses the remaining three recording tracks. . Waveform 1 is the output waveform of the detection circuit 26, waveform j is the output waveform of the Schmitt gate circuit 27, waveform k is the output waveform of the differentiating circuit 28, and waveform 1 is the rectifier circuit 30.
This is the output waveform of Further, waveform m is the output waveform of the difference circuit 25, waveform n is the output waveform of the rectifier circuit 33, waveform 0 is the output waveform of the inverting circuit 35, waveform p is the output waveform of the AND circuit 34,
The waveform q is the output waveform of the AND circuit 36, the waveform r is the output waveform of the flip-flop circuit 37, and the waveform s is the output waveform of the inversion circuit 31. When the circuit is configured in this way, the signal when the light beam 2 crosses the recording track 20 on the recording disk 3 is obtained from the output of the inverting circuit 31, and the moving direction of the pickup device 4 at that time is obtained from the flip-flop circuit 37. Obtained from the output. Next, a description will be given of how the system operates when the search address of a desired image is input into the input device 12.

If the output of the input device 12 is A1, and the search address of the recording track on the recording disk 3 currently irradiated by the light beam 2, that is, the output of the address reading circuit 13 is B, then the arithmetic circuit 14 calculates 2n+1+A-B. , and presets this value in the up/down counter 15. The DA converter 16 adds 2n+1 to A-B in the calculation of the arithmetic circuit 14.
This is to use. To explain this, for example, in the case of a 14-bit D-A converter, Figs.
You can obtain the input relationship shown in the figure. In other words, D-A
When the input of the converter is 214, the output is zero, and when the input is zero, the output is +5V1.When the input is (215-1), the output is -
It is 4.99985V. This is just an example; the input/output relationship can also be reversed. Therefore, (M+1) bits of DA
In the case of the converter 16, the output can be zero when the input is 2n+1. Output 2n+1+A-B of arithmetic circuit 14
is preset in the up-down counter 15, and the drive element 18 is driven to move the pickup device 4. At the same time, the signal crossing the recording track 20 on the recording disk 3 output from the movement detection circuit 11 and the pickup Device 4
If the up/down counter 1/f 5 is operated by a signal in the direction of movement, when the light beam 2 reaches the recording track 20 at the desired address, that is, the address input to the input device 12,
The output of the DA converter 16 becomes zero and the drive element 18 stops. When A>B, the pickup device 4 moves from the outer circumference of the recording disk 3 toward the inner circumference. At this time, the up/down counter 15 is in the down mode, and the light beam 2
decreases by one each time it crosses a recording track 20 on the recording disk 3, and when the light beam 2 reaches the desired recording track 20, the output of the up/down counter 15 is 2n+1.
Therefore, the output of the DA converter 16 becomes zero. In the case of B>A, the pickup device 4 moves from the inner circumference of the recording disk 3 toward the outer circumference. At this time, up/down counter 1
5 is in the up mode, and each time the light beam 2 crosses the recording track 20 on the recording disk 3, it increases by one.
When the light beam 2 arrives on the desired recording track 20,
The output of the up/down counter 15 becomes 2°+1, and D
-The output to the A converter 16 becomes zero. Since the retrieval device of the present invention employs closed-loop control, even if the desired recording track 20 is overstepped, a voltage in the opposite direction is applied to the drive element 18, so that the pickup device is automatically returned. In the above embodiment, the search address is set at address 1 at the innermost recording track on the recording disk 3, and at address 2 toward the outer circumference.
3, 4...may be recorded as addresses. Record disc 3
If the number of tracks recorded above is N, and the number of bits of the binary number L when N is converted into binary is M, then the number of bits of the D-A converter 16 should be (M+1) bits or more. . D-A when the output of the D-A converter 16 becomes zero
The input of the converter 16 can be any number greater than or equal to the binary number L of N. There is no problem even if the configuration is such that the light beam 2 transmitted through the recording disk 3 is received by a photodetector. Further, instead of detecting the signal across the recording track and the moving direction of the pickup device 4 using the output of the photodetector 9, a rotary encoder or a linear encoder may be used. All that is required is to know the relationship between the interval between the output pulses of the encoder and the moving distance of the pickup device 4, and the interval between the recording tracks 3, that is, the track pinch. The address difference between the recording track where the light beam 2 is currently located and the desired recording track may be replaced with the number of output pulses from the encoder. If the interval between the output pulses of the encoder is wider or narrower than the track pitch, the pickup device does not necessarily stop with the light beam positioned on the desired recording track 20.
In such a case, a method such as rotating the total reflection mirror 6 may be used. Instead of moving the pickup device 4, the electric motor 10 and the recording disk 3 may be moved. Instead of reading the recording track address on the recording disk 3 where the light beam 2 is currently located, the light beam 2 may be fixed at the position where the search starts and always start moving from that position. As explained above, even if there is eccentricity, the search device of the present invention is not affected by eccentricity, and since the control system is a closed loop, it is not affected by changes in dynamic frictional force or static frictional force. You can receive the information you want reliably and quickly.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of a recording disk, and FIGS. 3 to 5 are explanatory diagrams when a light beam traverses recording tracks on the recording disk. and its waveform diagrams, FIGS. 6 and 7 are bookmark diagrams for detecting the moving direction of the pickup device, and waveform diagrams of various parts, FIG. 8,
FIG. 9 is an explanatory diagram of the DA converter. 2...Light beam, 3...Recording disk, 4...Zeckup device, 11...Movement detection circuit, 12...Input device, 13...Address reading device, 14...Arithmetic device, 15... Up/down counter, 16... DA converter, 17... Drive circuit, 18... Drive element.

Claims (1)

[Scope of Claims] 1. A device for reproducing signals recorded on a record carrier by converging and irradiating a light beam generated from a light source onto a record carrier, the apparatus comprising: a reproducing means for reproducing a signal recorded on the record carrier from the transmitted light beam; an address reading means for reading the address of a track on the record carrier where the light beam is located from the signal of the reproducing means; a moving means for relatively moving the light beam in a direction substantially perpendicular to the track direction; a moving amount detecting means for detecting the amount of movement of the light beam on the record carrier when the moving means is driven; an address input means for inputting the address of a desired track; and calculation of the amount of movement, including the direction, by which the moving means should move based on the difference between the address read by the address reading means and the address input to the address input means. a calculating means for calculating the value of the calculating means as an initial value, a counting means for counting the signal of the movement amount detecting means output when the moving means is driven, and an analog signal corresponding to the output of the counting means. A search device comprising: a digital-to-analog conversion means for outputting a signal; and a drive means for driving the moving means in accordance with a signal from the digital-to-analog conversion means. 2. Detect the positional deviation between the light beam and the track on the record carrier from the light beam reflected by or transmitted through the record carrier, and calculate the amount of movement of the light beam on the record carrier based on the detected positional deviation signal. The search device according to claim 1, characterized in that the search device is configured to detect. 3 Detecting the positional deviation between the light beam and the track on the record carrier from the light beam reflected by the record carrier or transmitted through the record carrier, and detecting the positional deviation between the light beam and the track on the record carrier using the detected positional deviation signal and the signal from the reproducing means. 2. The search device according to claim 1, wherein the search device is configured to detect the amount of movement of the beam. 4. Claim 1, characterized in that the signal envelope of the reproduction means is detected, and the amount of movement of the light beam on the record carrier is detected from the detected envelope signal and positional deviation signal. Search device described. 5. A photodetector having first and second light-receiving areas that receive a light beam reflected by or transmitted through the record carrier, and combining signals of the first and second light-receiving areas of this photodetector. A reproducing means is configured with a combining circuit that detects the positional deviation between the light beam and the track on the record carrier from the difference between the signals of the first and second light-receiving areas of the photodetector, and detects the positional deviation between the light beam and the track on the record carrier. 2. The retrieval device according to claim 1, wherein the amount of movement of the light beam on the record carrier is detected from the signal and the signal from the combining circuit. 6. The search device according to claim 1, wherein the most significant digit signal of the digital signal input to the digital-to-analog conversion means determines the moving direction of the moving means.