JP3004838U - A device for detecting the beginning and end of tape on a tape deck - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention relates to a device for detecting the beginning and end of a tape in a tape deck, and it is intended to prevent the sensitivity of the light receiving element from being lowered or the malfunction due to the light receiving element receiving only the light beam from the light emitting element. To aim. A light emitting element 25 and a light receiving element 26 assembled on a printed circuit board 23, a prism 27 for guiding the light of the light emitting element 25 in a predetermined direction, and a light passing through the prism 27 to a light receiving element 26 by bending the light. The light receiving element 2 has a reflecting surface 32a for guiding and the reflecting surface 32a.
6 is composed of a tubular body 31 having a U-shaped cross section, which is made of an opaque member that covers the periphery of the optical path, and a guide plate 17 for mounting the tubular body 31 having the U-shaped cross section. Characterize.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape trailing end detecting device in a tape deck, for example, to a tape trailing end detecting device in a tape deck for detecting the leading end or the trailing end of a cassette tape incorporated in a cassette tape recorder. The signal handled by the tape deck may be video, audio, digital, or a combination thereof or any other form.

[0002]

[Prior art]

 Generally, as a device for detecting the beginning and end of the tape on the tape deck, a light emitting element is provided in the center of the tape deck, and light receiving elements are provided on both sides of the tape deck so that the light from the light emitting element is used as the beginning and end of the tape. The tape end is detected by hitting the tape for tape end detection provided at the end and the transmitted light is received by the light receiving element. For example, as shown in FIGS. 8 and 9, there are conventional ones for detecting the beginning and end of the tape. An auxiliary print substrate 53 for mounting the light receiving element 52 at a position where the light emitted from the light emitting element 51 provided in the central portion of the chassis 57 of the tape deck 50 can be received is attached to the side wall 57a of the deck chassis 57, and this auxiliary printing is performed. There is one in which the light receiving element 52 is soldered to the board 53 and the main printed board 54 and the auxiliary printed board 53 on the lower side of the deck chassis are connected by the lead wire 55.

Further, as another example, as shown in FIG. 10, there is a prism cylindrical body 56 made of a transparent resin such as acryl, which is provided with an inclined surface 56a. The light beam from the light emitting element 51 is introduced through the prism tube body 56, is reflected by the inclined surface 56a, is guided to the lower end surface of the prism tube body 56, and is guided to the light receiving element 52 on the main printed circuit board 54 installed at this position. The light is received by the light receiving element 52.

[0004]

However, in such a conventional tape end detecting device, the periphery of the light receiving element 52 is open, so that not only the light beam from the light emitting element 51 but also external light is received. There is a problem that the amount of light rays that enter the light receiving element 52 and enter the light receiving element 52 is increased, and the sensitivity of the light receiving element 52 is lowered or malfunction occurs.

Further, when the transparent resin prism cylinder 56 as shown in FIG. 10 is used, even if a light beam from the outside does not directly enter the light receiving element 52, if it enters the prism cylinder 56, the prism There is a drawback that the wall surface of the cylindrical body 56 is reflected and is guided to the light receiving element 52 to cause the above-mentioned problems. Further, the position of the light receiving element 52 on the main printed circuit board 54 is determined by the position of the prism cylinder 56, which may be difficult to change. Therefore, the prism cylinder 56 for adjusting the light reception by the light receiving element 52 is difficult. There was a problem that it was difficult to adjust the position.

Therefore, according to the present invention, by covering the vicinity of the reflection plate that reflects the light from the light emitting element to the light receiving element side and the circumference of the optical path of the light to the light receiving element with an opaque member, An object of the present invention is to prevent the sensitivity of the light receiving element from being lowered or malfunction by allowing the light receiving element to receive only light rays.

[0007]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, a device for detecting the beginning and end of a tape in a tape deck of the present invention comprises a light emitting element and a light receiving element assembled on a printed circuit board, a prism for guiding the light of the light emitting element in a predetermined direction, A tube having a U-shaped cross section, which has a reflecting surface for bending the light passing through the prism and guiding it to the light receiving element, and a non-transparent member that covers the circumference of the optical path near the light receiving element. And a guide plate for mounting the tubular body having a U-shaped cross-section.

In addition, a cover plate that covers the periphery of the reflection surface is integrally formed on the cylindrical body having a U-shaped cross section, and the cover plate guides light to the light receiving element to the reflection surface. A light guide hole is formed, and a hook provided on the lid plate is inserted into a locking hole near the reflection surface to cover the periphery of the reflection surface. is there.

The tubular body is attached by engaging a light guide hole of the lid with a hook provided on the guide plate. Further, the present invention is characterized in that the tubular body having a U-shaped cross section and the lid plate are integrally formed via a connecting band.

[0010]

[Action]

 The tape end detection device in the tape deck of the present invention comprises a light emitting element and a light receiving element mounted on a printed circuit board, a prism for guiding the light of the light emitting element in a predetermined direction, and a light passing through the prism. A cylindrical body having a U-shaped cross section, which has a reflecting surface for guiding the light receiving element to the light receiving element and the light reflecting element and which covers the periphery of the optical path in the vicinity of the light receiving element. Since it is composed of a guide plate for attaching the U-shaped cylindrical body, the circumference of the optical path of the light to the light receiving element is covered, the external light is blocked in the optical path, and only the light of the light receiving element to the light receiving element is blocked. Be guided.

Further, a cover plate that covers the periphery of the reflection surface is integrally formed on the tubular body having a U-shaped cross section, and the cover plate guides light to the light receiving element to the reflection surface. Since a light guide hole for the reflection surface is formed, and the hook provided on the lid plate is inserted into the locking hole near the reflection surface to cover the periphery of the reflection surface, the periphery of the reflection surface is Therefore, the light from the light emitting element is guided to the light receiving element because the external light ray is blocked.

Further, since the tubular body is attached by engaging the light guide hole of the lid with the hook provided on the guide plate, the tubular body can be attached to the guide plate with an inexpensive structure. . Further, since the tubular body having a U-shaped cross section and the lid plate are integrally formed via the connecting band, the periphery of the reflecting surface can be covered with an inexpensive structure. Therefore, it is possible to completely eliminate light leakage.

[0013]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of a tape end / end detecting device in a tape deck of the present invention. In FIGS. 1 and 2, 1 is a deck chassis having a rectangular shape in plan view, 2 is a rotatable head cylinder to which a recording / playback head and the like are attached, and 3 and 4 are slide bodies 7 and 8 which slide and guide via rails 5 and 6. Tape loading pins 10 and 11 for vertically mounting the magnetic tape 9a of the video cassette 9 on the cylinder 2 for supporting the tape reel of the cassette 9 for engagement and winding, and 12 for audio signals. No. 13 is an erasing head, 14 is a capstan, and 15 is a pinch roller.

Further, in the figure, 16 is a cassette holder for supporting the cassette 9, 17 and 17 are erected on the upper surface of the chassis 1, and the cassette holder 16 is movably attached to the cassette 9 in / out position or recording / reproducing position. Left and right guide plates, 19 is a tape running motor (flywheel) for rotating the capstan 14, and 20 is a loading motor for driving a tape loading lever and cassette loading gears 22 and 22 (not shown). The loading lever is slid to reciprocate the loading pins 3 and 4, and the loading gears 22 and 22 are reciprocated by the loading motor 20 to reciprocate the cassette holder 16.

Further, as shown in FIG. 2, a printed circuit board 23 for forming a recording / reproducing circuit and a motor control circuit is provided below the deck chassis 1. The printed circuit board 23 is provided on the lower surface of the chassis 1 with screws 24. The light-emitting diode 25, which is a light-emitting element, and the phototransistors 26, 26, which are light-receiving elements, are directly fixed and fixed to the substrate 23 while being fixed and fixed.

A central prism 27 made of acrylic resin in the shape of a quadrangular prism is provided, and the central prism 27 is locked and fixed to the chassis 1 by a hook 28 provided by insert molding process, and the lower end surface of the central prism 27 emits light. The left and right reflecting surfaces 29, 30 are formed at the upper end of the central prism 27 while facing the diode 25, and the light from the light emitting diode 25 is sent out to both sides via the reflecting surfaces 29, 30 of the central prism 27. Is configured as follows.

A tubular body 31 is attached to each of the left and right guide plates 17, 17 on both sides of the central prism 27 in the direction in which light is emitted. As shown in FIG. 2, the tubular body 31 is composed of a reflection plate 32 having a reflection surface 32a that reflects the light from the light emitting diode 25 toward the phototransistor 26 side, and a polystyrene resin that is an opaque member. While holding the reflecting plate 32, the cylindrical main body 31A formed to cover the periphery of the optical path from the reflective plate 32 side to the phototransistor 26 side in a U-shaped cross section, and one of the upper part of the cylindrical main body 31A. It is connected to the side end 31a at two upper and lower positions by flexible connecting bands 31b, and is provided with a lid plate 31B which can be locked to the other side end 31c by a hook 38 which is a locking portion.

A light guide hole 31 d for guiding light is provided at a position corresponding to the light emitting diode 25 side of the cover plate 31 B. A metal film, for example, an aluminum foil is formed on the reflecting surface 32a so that the incident light is reflected to the phototransistor 26 side.

In the thus constructed tape deck, the tubular body 31 is made of polystyrene resin which is an opaque member, and the optical path of light from the vicinity of the reflector 32 and the vicinity of the reflector 32 to the light receiving element is provided. Since it covers the surroundings, the optical path to the reflection plate 32 and the phototransistor 26 is blocked from external rays. Therefore, only the light from the light emitting diode 25 is guided to the phototransistor 26. Therefore, the sensitivity of the phototransistor 26 is excellent, and no malfunction occurs. Further, it is possible to eliminate the conventional auxiliary printed circuit board and the lead wire between the auxiliary printed circuit board and the main printed circuit board.

Further, in the above-described embodiment, as shown in FIG. 3, the position of the phototransistor 26 can be relatively changed by changing the angle of the reflecting surface 32a.

Next, another embodiment of the present invention will be described with reference to FIGS. This embodiment relates to the structure of the above-mentioned tubular body 31, and the same components as those in the above-mentioned embodiment are designated by the same reference numerals. The tubular body 31 has a hook 38, which is a locking portion formed at one side end of the lid plate 31B connected to one side end 31a of the upper portion of the cylindrical main body 31A, and a locking hole formed at the other side end 31c. It is designed to be inserted into 39 and locked. Further, when the hook 38 is detached from the locking hole 39, as shown in FIGS. 4 and 5, the cylinder main body 31A and the cover plate 31B can be developed in a plane and can be manufactured as an injection molded product. .

Then, a convex portion 44 and a concave portion 46, which are in a fitting relationship, are formed on the inner periphery of the front surface portion 31e of the tubular main body 31A and the corresponding portion of the lid plate 31B to connect the lid plate 31B to the connecting band. When the front portion 31e and the cover plate 31B are folded back from 31b and overlapped with each other, it is possible to prevent a discrepancy between the two positions due to the fitting relationship.

Therefore, after a reflective aluminum foil capable of forming a metal film and reflecting light rays is attached to the reflective surface 32a, the cover plate 31B is folded back from the connecting band 31b, and the cover plate 31B and the front surface portion 31e are The convex portion 44 and the concave portion 46 are overlapped with each other without shifting their positions, and the hook 38 is engaged with the locking hole 39 to lock the hook 38, whereby the assembly of the tubular body 31 is completed.

The tubular body 31 is attached at a desired position by engaging the hook 17b of the guide plate 17 provided on the reflection side with the light guide hole 31d as shown in FIG. 7, and is attached to the printed circuit board 23. The phototransistor 26 is housed in the cylinder main portion 31A.

Since the tubular body 31 of this embodiment has the above-mentioned configuration, the light emitting diode 25 or its reflected light enters the tubular body 31 through the light guide hole 31d and is reflected by the reflecting surface 32a. The light passes through the cylindrical main body 31A and is received by the phototransistor 26. The surface that is a space with respect to the wall surface of the U-shaped three surfaces is closed by the side wall of the guide plate 17. Therefore, the external light rays cannot reach the inside of the tubular body 31, and the sensitivity deterioration and malfunction of the phototransistor 26 can be prevented as in the previous embodiment.

Further, unlike the previous embodiment, the auxiliary printed circuit board and the wiring of the lead wires are not required, and since the tubular body 31 can be molded by an integral structure of injection molding, a large number can be formed by injection molding using a mold. It can be manufactured quickly, the unit price of parts can be greatly reduced, and the guide plate 17 can be easily attached to the side wall only by inserting it, and the assembly cost can be significantly reduced.

[0027]

[Effect of device]

 According to the present invention, a light emitting element and a light receiving element mounted on a printed circuit board, a prism for guiding the light of the light emitting element in a predetermined direction, and a reflection for guiding the light passing through the prism to the light receiving element. A cylindrical body having a U-shaped cross section and a light-transmissive member that has a surface, the reflection surface, and covers the circumference of the optical path in the vicinity of the light receiving element, and the cylindrical body having the U-shaped cross section. Since it is configured with a guide plate for the above, the periphery of the optical path of light to the light receiving element is covered, the external light is blocked in the optical path, and only the light of the light receiving element is guided to the light receiving element. Therefore, it is possible to prevent a decrease in sensitivity and malfunction.

Further, a cover plate that covers the periphery of the reflection surface is integrally formed on the tubular body having a U-shaped cross section, and the cover plate guides light to the light receiving element to the reflection surface. Since a light guide hole for the reflection surface is formed, and the hook provided on the lid plate is inserted into the locking hole near the reflection surface to cover the periphery of the reflection surface, the periphery of the reflection surface is Therefore, the light from the light emitting element is guided to the light receiving element because the external light ray is blocked.

Further, since the tubular body is attached by engaging the light guide hole of the lid with the hook provided on the guide plate, the tubular body can be attached to the guide plate with an inexpensive structure. . Further, since the tubular body having a U-shaped cross section and the lid plate are integrally formed via the connecting band, the periphery of the reflecting surface can be covered with an inexpensive structure. Therefore, it is possible to eliminate light leakage.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a device for detecting the beginning and end of a tape in a tape deck according to the present invention.

FIG. 2 is a cross-sectional view of a main part of the embodiment shown in FIG.

FIG. 3 is a cross-sectional view of a reflective tape portion of the embodiment shown in FIG.

FIG. 4 is an exploded perspective view of another embodiment of the present invention.

5 is a developed plan view of the embodiment shown in FIG.

6 is a sectional view taken along line AA of the embodiment shown in FIG.

7 is a sectional view of the embodiment shown in FIG. 4 in a mounted state.

FIG. 8 is a schematic plan view of a tape trailing edge detecting device in a conventional tape deck.

FIG. 9 is a side view of a conventional tape end detecting device.

FIG. 10 is a side view of another conventional tape end detection device.

[Explanation of symbols]

 17 guide plate 17b hook 25 light emitting element 26 light receiving element 27 central prism (prism) 31 tubular body 31A tubular body 31B cover plate 31b connecting band 31d light guide hole 32a reflecting surface 38 hook 39 locking hole

Claims (4)

[Scope of utility model registration request] 1. A light emitting element and a light receiving element assembled on a printed circuit board, a prism for guiding the light of the light emitting element in a predetermined direction, and a reflecting surface for bending the light passing through the prism and guiding it to the light receiving element. And a tubular body having a U-shaped cross section, which has the reflection surface and covers the periphery of the optical path near the light receiving element, and the tubular body having a U-shaped cross section. A tape guide plate for detecting the beginning and end of a tape in a tape deck. 2. A cover plate that covers the periphery of the reflection surface is integrally formed on the cylindrical body having a U-shaped cross section, and the cover plate is for guiding light to a light receiving element to the reflection surface. 2. The light guide hole is formed, and a hook provided on the cover plate is inserted into a locking hole near the reflection surface to cover the periphery of the reflection surface. A device for detecting the beginning and end of tape on a tape deck. 3. The tape end of the tape deck according to claim 2, wherein the tubular body is attached by engaging a light guide hole of the lid with a hook provided on the guide plate. Detection device. 4. A tape deck according to claim 2, wherein the tubular body having a U-shaped cross section and the cover plate are integrally formed via a connecting band. apparatus.