JPH0159659B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to a tape-type optical recording medium that optically records information at high density in digital or analog format on a tape as an optical recording medium, and optically reproduces information from the tape. The present invention relates to a type recording/reproducing device.

Background Field Magnetic tape is currently common and widely used as an information recording medium, but due to its nature, magnetic tape has limitations in achieving high density recording and improving noise characteristics. 2. Description of the Related Art Optical recording and reproducing devices that record and reproduce information using a laser beam spot have been attracting attention and being developed. These optical recording and reproducing devices are roughly divided into those that use tape as the optical recording medium and those that use disk.
The present invention relates to an improvement of the former tape type.

Tape-type optical recording and reproducing devices record information by forming micro holes (information pits) of about 1 μm on the tape by irradiating the tape with a laser beam spot, and then irradiating the tape with the information recorded with the laser beam spot. The information is reproduced by detecting the reflected light or transmitted light. A long tape is used as this optical recording medium, and information is recorded and reproduced while being fed from a feed reel to a take-up reel. A pair of reels for winding and storing the above-mentioned tape are rotatably stored in a housing made of plastic or the like to form a cassette.

The above-mentioned optical recording and reproducing apparatus using a cassette tape requires at least a tape drive control mechanism in the cassette tape and an optical head for recording and reproducing.This basic conventional example is explained with reference to FIG. 1.1 is a cassette tape. There are two first and second reels 3 and 4 in a rectangular thin box-shaped plastic housing 2.
are rotatably arranged at regular intervals on the same plane with their axial directions parallel to each other, and the tape 5 wound on the first reel 3 for feeding passes through a plurality of tape guides 6, 6... to the second reel for winding. It is wound onto reel 4. The tape 5 is, for example, a plastic tape with Te-
The recording layer is made of a thin metal film such as As-Se. Reference numeral 7 denotes an optical head, which has a structure in which optical pickups 9 are attached to at least two locations on the outer circumferential surface of a rotating drum 8, and is attached to an external device in which the cassette tape 1 is set. During recording and playback, the first and second reels 3 and 4 of the set cassette tape 1
A part of the tape 5 in between runs in a curved manner, and a rotating drum 8 approaches the outer surface of this curved part 5' at a constant inclination angle θ as shown in FIG. Rotate. Then, the optical pickup 9 helically scans the recording layer on the outer surface of the tape 5 at an angle θ, and during recording, the recording layer is irradiated with a laser beam spot modulated by information to continuously form information pits, and for reproduction. At the time, a laser beam spot is irradiated in the track direction of the information pit and the reflected light is read. The information tracks T formed by the information pits recorded on the tape 5 are densely formed at an angle θ as shown in FIG. recorded. The arrangement pitch P of the tracks T is determined by the feeding speed of the tape 5.

Although such an optical recording/reproducing device enables high-density recording, it is currently difficult to put it into practical use because it includes the following problems.

(a) The external device into which the cassette tape 1 is set includes a motor for rotating the first and second reels 3 and 4 of the cassette tape 1 and a motor for rotating the optical head 7, similar to a magnetic tape recorder. They require many types of motors (usually four or more types) and tend to be expensive and large.

(b), the curved running surface of the tape 5 facing the rotating drum 8 is approximately half the circumference of the rotating drum 8, and therefore, in the case of the helical scan method, at least two pick-ups 9 are required for recording and reproducing.
It is necessary to attach it to the circumferential surface of the rotating drum 8,
The structure of the optical head 7 becomes complicated.

(c) The optical pickup 9 in the optical head 7 includes at least a laser light source, a lens system that focuses the laser light emitted from the laser light source and irradiates it onto the tape 5, and a light receiving element that photoelectrically converts the light reflected from the tape 5. It also has a complex structure that movably supports the objective lens of the lens system for focus control and tracking control of the laser beam spot irradiated onto the tape 5. Therefore, when rotating this at high speed, it is difficult to electrically connect the optical pickup 9 to an external electric circuit, and the position of the movable objective lens fluctuates due to centrifugal force during high-speed rotation, making focus control and tracking control difficult. It becomes difficult.

(d) Since the recording surface of the tape 5 slides directly or indirectly on the outer peripheral surface of the optical head 7, the recording surface of the tape 5 may be scratched and cause noise generation. , Also, for this reason, the durability of the tape 5 is poor.

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above problems.
To provide a tape type optical recording and reproducing device in which recording and reproducing are performed by helical scanning the tape in the longitudinal direction while rotating the entire tape at high speed in front of a fixed optical head.

A feature of the present invention is that a cassette tape is housed in a single housing with a tape feed reel, a tape take-up reel, and a third reel for recording and playback, and these three reels are arranged coaxially. , the three reels are simultaneously rotated at high speed in the same direction, and the tape is run around the outer periphery of the third reel by controlling the rotational speed of the three reels. Another feature of the present invention is that recording and reproduction are performed by irradiating a laser beam spot from a fixed direction onto the tape running on the third reel of the cassette tape using a fixed optical head. With this configuration, the rotation of the three reels in the cassette tape can be driven by a single motor, and there is no need to rotate the optical head. Therefore, the total number of motors is minimized, reducing the overall size, weight, and cost. In addition, by using a fixed optical head, the design of the optical pickup is easy and the operation is stable, all of the above-mentioned problems of the conventional system are solved.

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 4 shows the entire device, and FIGS. 5 and 6 are for explaining a cassette tape. In FIG. 4, 10 is a case body, and 11 is a case body 10. In the built-in reproduction display device, 12 is a cassette tape 13 is a recess provided in the case body 10 for mounting a cassette tape. One unidirectional constant speed rotation drive motor 14 is installed approximately in the center of the bottom surface of the recess 13.
An optical head 16 is fixedly arranged on one of the two opposing side wall surfaces, and two rollers 18 and 19 of a rotational drive control mechanism 17, which will be described later, can protrude from the other side. Placed. 20
is a lid with a transparent window that closes the recess 13 as appropriate.
Note that the display device 11 is not limited to the example shown in FIG.
It is also possible to use separate pieces.

As shown in FIG. 5, the cassette tape 12 is constructed by rotatably housing a reel unit 22 in which three reels are combined in a substantially rectangular box-shaped housing 21 with a bottomed opening, and connecting the opening of the housing 21 with a housing lid. It has a sealed structure. The housing 21 and its lid 23 are made of plastic.
are screwed to the four corners of the housing 21 with screws 24. In the center of the front wall 21a of the housing 21, there is a transparent recording/reproducing window 25 through which laser light passes.
Notches 26 and 27 are formed in the rear wall 21b to accommodate the rollers 18 and 19, and a bearing 28 is formed in the center of the bottom surface 21c to bear the reel unit 22 and through which the motor rotation shaft 15 is inserted. be done. A long window 29 for checking the remaining amount of tape is formed in the housing lid 23, extending from the center to the periphery. The long window 29 and the transparent window 25 are unnecessary if the housing 21 and the housing cover 23 are made of transparent plastic.

As shown in FIG. 6, the reel unit 22 has a first reel 30 for feeding out the tape and a second reel 30 for winding the tape.
A reel 31 and a third recording/reproducing reel 32 are coaxially assembled. The third reel 32 is composed of a coaxial outer cylinder 32a, an inner cylinder 32b, and a partition plate 32c that divides the space surrounded by both into two in a direction perpendicular to the axial direction. Cutouts 34 and 35 are formed at one location each at a height equal to the tape width. In each ring-shaped space above and below the third reel 32, the first reel 30 and the second reel 31 connect the respective center holes 30' and 31' to the inner cylinder 32.
It is rotatably inserted into b and housed coaxially. 1st
A long tape 36 is wound in the same direction on the reel 30 and the second reel 31, and the first reel 30
The tape 36 extending from the outer cylinder 3 of the third reel 32
It comes out from the notch 34 of 2a and extends around the outer circumference of the outer cylinder 32a.
The other notch 35 is wound slightly helically around the
From there, it is wound onto the second reel 31. In this way, when the tape 36 is wound around the third reel 32 one turn or more, the optical head 16 fixedly arranged opposite to the tape 36 is wound around the third reel 32.
Recording and reproduction can be easily performed on the drum, and there is no need to attach two or more pickups to the drum and rotate them, as was the case in the past. A tape 3 is attached to the outer periphery of the outer cylinder 32a.
A guide groove 37 into which the tape 36 is fitted is formed, thereby preventing the tape 36 from shifting on the outer cylinder 32a. The first and second reels 30, 31 are plastic products in which circular outer rings 30b, 31b and inner rings 30c, 31c are integrally connected to the upper and lower ends of tape winding cylinders 30a, 31a, respectively, as shown in FIG. The outer diameter of the outer ring 30b of the first reel 30 is D ₁ , the second
When the outer diameter of the outer ring 31b of the reel 31 is D ₂ and the outer diameter of the outer cylinder 32a of the third reel 32 is D ₃ , D ₁ <D ₃
< _D2 , each outer ring 30b, 31
b rotates along the upper and lower end surfaces of the outer cylinder 32a. In addition, the inner rings 30c of the first and second reels 30 and 31,
31c has an outer diameter smaller than the inner diameter of the outer cylinder 32a. The tape 36 used has an optical recording surface on its outer surface, and its material may be the same as conventional tapes.

The cassette tape 12 is set in the recess 13 of the case body 10 as shown in FIG. That is, the motor rotation shaft 15 is inserted into and set in the inner tube 32b of the third reel 32 in the reel unit 22, and at this time, the optical head 16 faces the center of the outer periphery of the third reel 32, and is the first,
It faces the outer periphery of the outer rings 30b, 31b of the second reels 30, 31 from one direction. An engaging portion for preventing idle rotation is formed between the motor rotation shaft 15 and the inner cylinder 32b of the third reel 32, and the motor rotation shaft 15 is designed to always rotate in a constant direction at a constant speed, thereby at least The third reel 32 rotates integrally with the rotating shaft 15 in a constant direction at a constant speed. The roller 18 facing the outer ring 30b of the first reel 30
is an accelerating roller for returning the tape, the part facing the outer ring 30b has a large diameter, and the outer cylinder 3 of the third reel 32
A rubber member whose portion facing 2a has a small diameter is rotatably supported by a support 38 that swings in the horizontal direction. On the other hand, the roller 19 facing the outer ring 31b of the second reel 31 is a brake roller for tape feeding, and is rotatably supported by a horizontally swinging support 39 with a constant torque brake applied thereto.

Next, the recording and reproducing operation with the above configuration will be explained.

First, during recording or reproduction, only the tape feeding brake roller 19 is moved forward as shown in FIG. 8 to bring it into elastic contact with the outer periphery of the outer ring 31b of the second reel 31, and in this state, the motor rotation shaft 15 is moved forward as shown in FIG. Rotate at high speed in the direction of the arrow. Then, since the third reel 32 is integrated with the motor rotating shaft 15, the entire reel unit 22 rotates at high speed. At this time, since the brake is applied only to the second reel 31 from the outside, only the second reel 31 rotates slower than the others.
Apparently, the second reel 31 rotates in the opposite direction to the first reel 30, so that the tape 36 is rotated at high speed as a whole from the first reel 30 to the third reel.
The outer periphery of the reel 32 is helically scanned, and it travels at a constant speed to the second reel 31 and is wound up. To record information, if a laser beam spot is irradiated from the optical head 16 onto the tape 36 on the third reel 32 from the perpendicular direction in synchronization with the rotation of the reel unit 22 in the state shown in FIG. An information track T inclined at a constant angle is formed and executed. Information is reproduced in the same way using reel unit 22.
The laser beam spot is irradiated from the same direction by rotating the laser beam, and the reflected light is received by the optical head 16 and photoelectrically converted. The information image obtained from the tape 36 during this reproduction is displayed on the screen of the display device 11.

When it is desired to freeze the image displayed on the screen of the display device 11, the brake roller 19 is separated from the second reel 31 while the reel unit 22 continues to rotate at high speed, as shown in FIG. Then, all of the reel units 22 including the second reel 31 rotate at the same speed and the feeding of the tape 36 is stopped, and the laser beam spot repeatedly scans only one information track T, and the display device 11 A still image is displayed on the screen.

When rewinding the tape 36 from the second reel 31 to the first reel 30 after recording or playback is completed, at this time the reel unit 22 is rotated at high speed in the same direction as shown in FIG. By moving only the roller 18 forward, its large diameter portion 18a
The outer circumference of the outer ring 30b of the first reel 30 is pressed against the outer circumference of the outer ring 30b of the first reel 30, and the small diameter portion 18b is pressed against the outer circumference of the outer ring 30b of the third reel 32.
Press it against the outer periphery of 2a. Then, the roller 18 rotates at the driven rotational speed of the small diameter portion 18b that corresponds to the third reel 32, thereby accelerating the rotational speed of the first reel 30 that corresponds to the large diameter portion 18a.
Rotates faster than the third reel 31, 32, and the tape 3
6 travels from the second reel 31 to the outer periphery of the third reel 32 and is rewound onto the first reel 30.

Such first, second and third reels 30, 3
The rotational drive control mechanism 17 controls tape feeding, tape feeding stop, and tape rewinding by controlling the rotational speeds of rollers 18 and 32. In order to make the explanation easier to understand, an example of the configuration of each of the rollers 18 and 19 is given. In reality, in order to obtain stable operation, it is desirable to employ a non-contact mechanism such as a magnetic brake structure or an air brake structure.

As described above, according to the present invention, the cassette tape is miniaturized by coaxially stacking the reels,
Furthermore, since each reel of the cassette tape only needs to be rotated by one rotating shaft, the number of motors on the external equipment side for setting the cassette tape is greatly reduced, making it possible to reduce the overall size and cost. Furthermore, since the optical head is fixed at a fixed position, the electrical connection structure of the optical pickup is easy and stable, and control of the movable objective lens is also stable, so that focus and tracking control can be performed with high precision. Furthermore, since the tape runs between reels without the outer recording surface touching external members, there is no damage to the recording surface, stabilizing noise characteristics and extending the life of the tape.

[Brief explanation of drawings]

Figures 1 and 2 are a schematic plan view and partially enlarged front view of a conventional optical cassette tape and optical head;
Figure 3 is a partial view of the optical recording medium tape, Figure 4
5 is an exploded perspective view of the cassette tape of FIG. 4, FIG. 6 is an exploded perspective view of the reel unit of FIG. 5, and FIG. 7 is an exploded perspective view of the reel unit of FIG. 5. Enlarged sectional views of Figures 8 to 1
FIG. 0 is a side view of a main part during each operation for explaining the operation of the present invention. 12...cassette tape, 16...optical head,
17... Rotation drive control mechanism, 30... First reel, 31... Second reel, 32... Third reel,
36...Tape.

Claims (1)

[Claims] 1. No. 1 for feeding the tape, which is an optical recording medium.
A reel, a second reel for winding, and a third reel for recording and playback, which is located between the first and second reels, and the tape from the first reel runs around the outer circumference in a helical scan method and is sent to the second reel. a cassette tape rotatably disposed coaxially; a rotational drive control mechanism that rotates the three reels at high speed and controls feeding, stopping of feeding, and rewinding of the tape by controlling the rotational speed of the three reels; 1. An optical recording and reproducing apparatus comprising: a fixed optical head that irradiates a recording and reproducing laser beam from a fixed direction onto a tape on a third reel of the tape;