JPH1131346A - Video deck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video deck capable of reducing power consumption. SOLUTION: This video deck 10 detects a start end and a terminal end of a tape by using an LED having a light emission part 52a and a photosensor 52 consisting of a start end detecting phototransistor 52b and a terminal end detecting phototransistor 52c conformed so as to hold a tape traveling path in-between on the LED. In such a case, since a current supply to the LED in increased/decreased according to need, based on control of a system controller 60, whole power consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a video deck, and more particularly, to a video deck capable of detecting a tape end.

[0002]

2. Description of the Related Art Conventionally, as this kind of technology, a tape is sandwiched between a photosensor comprising an LED as a light emitting element and a phototransistor as a light receiving element which amplifies current based on incident light from the LED. In contrast, the amount of light emitted from the LED is always kept constant, and the leader and trailer of the tape are detected based on the current value flowing through the phototransistor.

On the other hand, in the tape end detecting device disclosed in Japanese Utility Model Laid-Open Publication No. 63-102034, a tape running amount is calculated from a rotation cycle of the tape, and a predetermined time before the end of the tape is calculated according to the calculation result. The photo sensor is operated, and the tape running is stopped when the photo sensor detects the trailer.

[0004]

The above-mentioned conventional video deck has the following problems.

[0005] In the former case, the LED needs to emit at least enough light to pass through a translucent reader and trailer. Therefore, its power consumption is completely ignored even in comparison with the power consumption of the entire VCR. Can not do. Therefore, if the LED is lit at a constant light amount until the power supply of the video deck is turned off or the tape is not loaded, power may be wasted. In the latter case, in order to calculate the tape travel distance, it is necessary to set the tape length in advance, and if the wrong setting is made, the photo sensor may not operate properly, In some cases, the tape was damaged.

[0006] The present invention has been made in view of the above problems, and has as its object to provide a video deck capable of reducing power consumption.

[0007]

According to a first aspect of the present invention, there is provided a light emitting device comprising: a light emitting element and a light receiving element which face each other so as to sandwich a tape traveling path; The configuration includes a photosensor for detecting the end and current control means for controlling the supply current to the light emitting element to increase or decrease.

[0008] In the invention according to claim 1 configured as described above, the light emitting element and the light receiving element constituting the photo sensor are opposed to each other so as to sandwich the tape running path. Comparing the case where the magnetic recording surface of the tape passes between the light emitting element and the light receiving element and the case where the leader at the beginning of the tape and the trailer at the end of the tape pass, the latter reaches the light receiving element. There is a lot of light. Therefore, the tape end can be detected if the current control means sets the supply current to the light emitting element so as to cross the threshold value on the light receiving element side by the difference in the light amount.

As described above, the photosensor detects the end of the tape. However, the current control means can set the current supplied to the light emitting element and control the amount of light emission. It can also be used for applications other than detection. As a preferred example, a case where the photosensor is used in combination as a tape sensor for detecting loading / unloading of a tape can be considered. As an example of a specific configuration in this case, according to a second aspect of the present invention, in the video deck according to the first aspect, the photosensor temporarily blocks the optical path during the tape insertion process. This detects the loading of the tape,
The current control means is configured to reduce a current supplied to the light emitting element when a tape is not loaded.

According to the second aspect of the present invention, the tape temporarily interrupts the optical path of the photosensor during the tape insertion process. The tape loading is detected based on the interruption of the tape. The current control means reduces the current supplied to the photo sensor until the photo sensor detects the loading of the tape. Needless to say, although the supply current is reduced, the current value is required to be at least such that the photosensor can surely detect the loading of the tape, and is set in advance by an experiment or the like.

In this case, the photosensor for detecting the tape end can be used as the tape sensor. However, since two functions are executed, only the tape sensor may be provided separately. Therefore, a third aspect of the present invention is the video deck according to the first aspect, further comprising a tape sensor for detecting loading / unloading of the tape, and the current control unit performs the following operations based on a detection result of the tape sensor. When the tape is loaded, the supply current is increased, and when the tape is not loaded, the supply current is reduced.

That is, the current control means increases the supply current to the photosensor when it is detected that the tape is loaded by a separately provided tape sensor, and conversely, when it is detected that the tape is not loaded. The current control means reduces the current supplied to the photosensor. The tape sensor here may detect the loading / unloading of the tape based on the shielding state of the optical path similarly to the photosensor described above, or may be a machine that performs a switching operation according to the loading / unloading of the tape. It may be a typical switch mechanism, and various forms are applicable.

By the way, even if the photosensor is used as a tape sensor, there is a case where the current supply to the photosensor may be completely stopped. In this case, the power consumption can be minimized. As a specific configuration, the invention according to a fourth aspect is the video deck according to any one of the first and second aspects, wherein the current control means is provided when the power supply of the video deck is turned off and the tape is loaded. In some cases, control is performed so that current is not supplied to the light emitting element.

That is, when the power supply of the video deck is turned on, it is easy to understand that the light emitting elements need to be turned on. On the other hand, when the VCR is turned off, if the tape is not loaded, it is necessary to turn on the light emitting element to detect the loading of the tape, but if the tape is already loaded, the tape is no longer Therefore, there is no need to supply a current to the light emitting element.

Various embodiments can be applied to the specific configuration of the photosensor. As an example, the invention according to claim 5 is the video deck according to any one of claims 1 to 4. Wherein the light emitting element is a light emitting diode and the light receiving element is a phototransistor. That is, light emitted from a light emitting diode as a light emitting element is incident on a phototransistor as a light receiving element, and the phototransistor amplifies current according to the incident light.

As another example, the invention according to claim 6 is the video deck according to any one of claims 1 to 5, wherein the light-emitting element and the light-receiving element are connected to each other through a mirror via a mirror. It is configured to confront with an optical path reciprocating in the path. In the invention according to claim 6 configured as described above, the light emitted from the light emitting element is incident on the mirror and reflected so as to reciprocate on the tape traveling path, and the reflected light is detected by the light receiving element. . By using the mirror in this way, the light receiving element can be provided in a place where the influence of the extraneous light is small.

On the other hand, as an example of a specific configuration of the current control means, the invention according to claim 7 is a video deck according to any one of claims 1 to 6, wherein the current control means comprises: A structure in which first and second current control resistors are connected in series to the light emitting element and connected in parallel with each other, and a current supplied to the light emitting element is controlled by controlling conduction of the current control resistor. There is. That is, the supply current to the light-emitting element changes by changing the energization pattern of the first and second current control resistors. As a more specific configuration, for example, various modes such as interposing a switching transistor in a power supply path connecting each current control resistor and the light emitting element and performing switching operation of the switching transistor appropriately to control energization are provided. Is applicable.

[0018]

As described above, the present invention provides a video deck which can be used as a tape sensor for detecting whether or not a tape is loaded while reducing the power consumption of the photosensor. can do. Further, according to the second aspect of the present invention, the loading of the tape can be detected with low current consumption. Further, according to the third aspect of the present invention, it is not necessary to determine whether to use the photosensor as a tape sensor, so that the current control of the photosensor becomes easy.

Further, according to the invention of claim 4,
When the power supply of the VCR was turned off and the tape was loaded, the current supply to the light emitting element was stopped.
Power consumption can be reduced. Furthermore, according to the invention according to claim 5, the photosensor can be configured with a simple configuration including the LED and the phototransistor.
Further, according to the invention of claim 6, since the light from the light emitting element is reflected by using the mirror, the light receiving element can be arranged at a place where the influence of the external light is small.

Further, according to the invention of claim 7,
The supply current to the light emitting element can be controlled with a simple configuration.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a video deck according to an embodiment of the present invention by a claim correspondence diagram, and FIG. 2 shows a specific hardware configuration example of the video deck by a block diagram. In FIG. 2, the video deck 10 includes a tuner 20 and can receive television broadcast waves. The received television broadcast waves are subjected to various signal processings in a signal system circuit 30, are RF-converted and output. . In addition, hardware for performing normal video playback and video recording is naturally provided, and is shown as a recording / playback unit 40 and a tape mechanism 50 in the figure.

The recording / reproducing section 40 includes a head group including a video head and an audio head (not shown) and an amplifier for amplifying a video signal or an audio signal to be recorded / reproduced. The input and output of the video signal and the audio signal are performed by the signal circuit 3
0 is performed. That is, at the time of video reproduction, the video signal and the audio signal reproduced by the head group are output and amplified by the amplifier,
And subjected to predetermined signal processing in the signal system circuit 30 and output. Also, when recording video,
The video signal and the audio signal input from the signal circuit 30 are
After being recorded and amplified by the amplifier, it is magnetically recorded by the head group.

The tape mechanism 50 includes a reel motor and a capstan motor (not shown) for driving and driving the tape, a tape motor 51 including a loading motor for tape loading, and various servo circuits (not shown).
A photo sensor 52 is provided. The system controller 60 controls the operation of the tape mechanism 50 including the signal system circuit 30 and the recording / reproducing unit 40 described above. The photo sensor 52 is
The light emitting unit 52a includes an LED and its peripheral circuit, a start-end detection phototransistor 52b, and an end-detection phototransistor 52c. FIG. 3 shows a state in which the tape T is loaded on the video deck 10 by a tape top view. In the figure, the LED is disposed so as to enter the inside of the housing of the loaded tape T. It is arranged on the take-up reel T1 side and the supply reel T2 side so as to face each other. The broken line in the figure indicates an openable and closable shielding plate T3 for protecting the tape.
Open during the loading process to expose the tape.

That is, when the tape runs, the above L
When a tape reader is positioned between the ED and the start-edge detection phototransistor 52b, the light emitted from the LED passes through the reader and reaches the start-end detection phototransistor 52b. The current value of the phototransistor 52b shows a high value. On the other hand, when the magnetic recording surface of the tape is located between the LED and the start-edge detection phototransistor 52b, the light emitted from the LED is almost completely blocked by the magnetic-recording surface. The current value of the transistor 52b becomes a low value. On the other hand, the same applies to the termination detection phototransistor 52c. When the trailer of the tape is positioned between the LED and the termination detection phototransistor 52c, the current value of the termination detection phototransistor 52c indicates a high value, LED and phototransistor 52 for termination detection
When the magnetic recording surface of the tape is located between the end of the phototransistor c and the end c, the current value of the termination detection phototransistor 52c becomes low.

The value of the current flowing through the start-end detection phototransistor 52b and the end-detection phototransistor 52c is input to the system controller 60. The system controller 60 detects the reader or trailer based on the current value and stops the tape running. Of course, the processing performed by the system controller 60 by detecting the leader or trailer is completely arbitrary. For example, when the trailer is detected, not only the tape running is stopped, but also the tape is rewound. Is also good.

In this embodiment, the LED is directly opposed to the start-end detection phototransistor 52b and the end-detection phototransistor 52c across the tape running path. However, the present invention is not limited to this configuration. For example, a mirror is provided instead of the start-end detection phototransistor 52b and the end-detection phototransistor 52c, and the incident light from the LED is appropriately reflected by the mirror, and the reflected light is detected by the phototransistor. Is also good. In this case, there is an advantage that the phototransistor can be arranged at a position where the influence of extraneous light is smaller.

The photo sensor 52 in this embodiment is
In the loading process of the tape T, the shielding plate T3 momentarily blocks the optical path between the LED and the start-end detection phototransistor 52b and the optical path between the LED and the end-detection phototransistor 52c during the loading process of the tape T. Then, the current values of the start-end detection phototransistor 52b and the end-detection phototransistor 52c both tend to decrease. The start-end detection phototransistor 52b includes:
Since the current values of the termination detection phototransistors 52c can both tend to decrease only during tape loading, the system controller 60 detects such a decrease in the current value and determines that the tape is loaded.

On the other hand, the same is true when the tape is ejected. After the shielding plate T3 momentarily blocks the optical path between the LED and the start-end detection phototransistor 52b and the optical path between the LED and the end-end detection phototransistor 52c. The tape is ejected. Therefore, the start-end detection phototransistor 52
Both b and the current value of the termination detection phototransistor 52c show an increasing tendency. Since the current values of both the start-end detection phototransistor 52b and the end-detection phototransistor 52c tend to increase only when the tape is ejected, the system controller 60 detects the increase in the current value and determines whether or not the tape current has increased. Judge as loaded.

By the way, in the prior art, the light emission amount of the LED is always kept constant even when the power supply of the video deck is turned off. However, if the light emission amount of the LED is kept constant until the power is turned off or the tape is not loaded, power may be wasted. Thus, in the present embodiment, the light emitting section 52a has a circuit configuration as shown in FIG. 4 so that the light emission amount of the LED can be controlled. In the figure, two current control resistors R1 and R2 connected in parallel to each other are connected in series to the LED, and a switching operation for switching operation is provided between the LED and the current control resistors R1 and R2. The digital transistors DTr1 and DTr2 are interposed, and the potential difference between both ends of the series of circuits is always constant. VCR 1 is provided on the base of digital transistor DTr1.
The signal voltage corresponding to 0 power on / off is
The signal voltage is set to a high level when the power is turned on and to a low level when the power is turned off. On the other hand, the digital transistor DT
A plurality of logic circuits (not shown) are used as a base of r2, and a high-level signal voltage is used when the video deck 10 is powered on and a tape is loaded, or when the power is off and the tape is not loaded. However, in other cases, a low-level signal voltage is applied from the system controller 60.

Digital transistors DTr1, DTr
2 is turned on when a high-level signal voltage is applied to the base, and the current control resistors R1 and R2 are energized. Otherwise, the current control resistors R1 and R2 are energized and the current control resistors R1 and R2 are energized. do not do. FIG. 5 shows a VCR 1
This table summarizes the supply current to the LEDs according to the power on / off of 0 and the loading / unloading of the tape in a table format.
As is clear from the figure, when the power is turned on and the tape is loaded, the supply current to the LED is at a high level (H), and the light emission amount of the LED only passes through the reader or trailer. The light intensity is sufficient. On the other hand, when the tape is not loaded, since only one of the current control resistor R1 and the current control resistor R2 is energized, the supply current to the LED is at a low level (L), and the light emission amount is smaller than the above case. Lower. That is, in this case, the light emission amount of the LED may be any light amount that can detect the loading of the tape. Further, when the power is turned off and the tape is loaded, there is no need to drive the tape or to detect the insertion of the tape. Therefore, the current supply to the LED is stopped so that the LED does not emit light. In this sense, the syscon 60 and the current control resistors R1 and R2
An LED peripheral circuit including the digital transistors DTr1 and DTr2 constitutes a current control unit.

With the above configuration, it is possible to reduce the power consumption of the VCR, but it is not always limited to this configuration. For example, when a tape sensor is provided separately, it is not necessary to consider using a photosensor as a tape sensor. Therefore, a simplified LED peripheral circuit as shown in FIG. 6 can be applied. . The LED peripheral circuit shown in the figure is obtained by removing the digital transistor DTr2 from the LED peripheral circuit shown in FIG.
The power supply to the LED is controlled only depending on the power on / off of the power supply. That is, when the power supply of the video deck 10 is turned on, the supply current to the LED increases, and when the power supply is off, the supply current to the LED decreases. Also in this case, the power consumption can be reliably reduced as compared with the conventional one.

Next, the operation of this embodiment configured as described above will be described with reference to a timing chart shown in FIG. In the initial state, it is assumed that no tape is loaded in the video deck 10 and the power is off. At this time, referring to FIG. 5, the digital transistor DTr1 is in the off state, the digital transistor DTr2 is in the on state, and a low-level (L) current is supplied to the LED. Here, when the power supply of the video deck 10 is turned on, the digital transistors DTr1 and DTr2 perform switching operations so as to be inverted, respectively, but the current supplied to the LED remains at a low level (L).

Thereafter, a tape is inserted into a tape inlet / outlet (not shown) of the video deck 10 and loaded. Then, in this loading process, the shielding plate constituting a part of the housing of the tape temporarily interrupts the optical path between the LED and the start-end detection phototransistor 52b and the end-end detection phototransistor 52c. 52b and termination detection phototransistor 52c
Both show a tendency to decrease for a moment.

When the system controller 60 detects such a decrease in the current value, only the digital transistor DTr2 switches to the ON state, the supply current to the LED becomes high (H), and the light emission amount of the LED becomes the tape reader or trailer. Will be sufficient to detect. When the tape is completely wound up, the first predetermined area on the tape surface is the leader, so the current value flowing through the start-end detection phototransistor 52b drops momentarily during tape loading, but the light emission amount of the LED decreases. It rises sharply in conjunction with the increase. And when you start playing,
When the magnetic recording surface of the tape approaches the optical path between the LED and the start-end detection phototransistor 52b, the current value of the start-end detection phototransistor 52b rapidly decreases. At the time of rewinding the tape, the syscon 60
A tape reader is detected based on a change in the current of the start-end detection phototransistor 52b, and the tape is stopped.

When the video reproduction is continued and the trailer approaches the optical path between the LED and the termination detection phototransistor 52c, the termination detection phototransistor 52c is activated.
The current value of c sharply increases. Upon detecting such a change in the current of the termination detection phototransistor 52c, the system controller 60 stops the tape running. After that, when the tape discharging process is executed, the shielding wall of the tape and the light path between the LED and the phototransistor 52c for detecting the end and the end between the LED and the phototransistor 52c for detecting the end are similar to the tape loading process. Block the light path for a moment. Therefore, in the discharging process, the start-end detection phototransistor 52 is used.
b increases, and the termination detecting phototransistor 5
The current value of 2c decreases momentarily and then increases. In any case, the current values of the start-end detection phototransistor 52b and the end-detection phototransistor 52c tend to increase, and the system controller 60 detects such a change in the current value to detect that the tape has been ejected. Then, the digital transistor DTr2 is turned off, and the current supplied to the LED also becomes low level (L).

If the video deck 10 is no longer used, the power is turned off. Then, the digital transistors DTr1 and DTr2 are switched so as to be inverted, respectively, and return to the initial state. On the other hand, when the power is turned off without discharging the tape, the digital transistors DTr1 and DTr2 are both switched from the on state to the off state, and the supply current to the LED is completely stopped. Of course, if the power is turned on from this state, the digital transistors DTr1, DTr2
It goes without saying that both are turned on and the supply current to the LED becomes high level (H).

As described above, the LED included in the light emitting portion 52a
And the video deck 10 capable of detecting the start and end of the tape using the photosensor 52 including the start-end detection phototransistor 52b and the end-detection phototransistor 52c that face each other with the tape running path interposed between the LEDs. Since the supply current to the LED is increased or decreased as needed based on the control of the system controller 60, a video deck capable of reducing power consumption as a whole can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to a claim of a video deck according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a hardware configuration example of the video deck.

FIG. 3 is a schematic diagram illustrating a positional relationship between an LED, a start-end detection phototransistor, and an end-end detection phototransistor.

FIG. 4 is a schematic circuit diagram of a light emitting unit.

FIG. 5 is a table showing supply currents to LEDs according to power on / off of a video deck and loading / unloading of a tape.

FIG. 6 is a schematic circuit diagram of a light emitting unit according to a modification.

FIG. 7 is a timing chart showing changes in current values of the LED, the start-end detection phototransistor, and the end-detection phototransistor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Video deck 20 ... Tuner 30 ... Signal system circuit 40 ... Recording / reproducing part 50 ... Tape mechanism 51 ... Tape motor 52 ... Photosensor 52a ... Light emitting part 52b ... Start-end detection phototransistor 52c ... End-end detection phototransistor 60 ... Syscon

Claims (7)

[Claims] 1. A photosensor comprising: a light emitting element and a light receiving element facing each other so as to sandwich a tape running path; and a photosensor for detecting an end of the tape based on a shielding state of an optical path, and increasing or decreasing a current supplied to the light emitting element. A video deck, comprising: 2. The video deck according to claim 1, wherein the photosensor detects the loading of the tape by temporarily blocking the optical path of the tape during a tape insertion process, and detects the loading of the tape. A means for reducing a current supplied to the light emitting element when a tape is not loaded. 3. The video deck according to claim 1, further comprising a tape sensor for detecting loading / unloading of the tape, wherein the current control means detects a time when the tape is loaded based on a detection result of the tape sensor. A video deck wherein the supply current is increased and the supply current is reduced when no tape is loaded. 4. The video deck according to claim 1, wherein said current control means does not supply current to said light emitting element when said video deck is powered off and a tape is loaded. VCR that is controlled as follows. 5. The video deck according to claim 1, wherein said light emitting element is a light emitting diode, and said light receiving element is a phototransistor. 6. The video deck according to claim 1, wherein the light emitting element and the light receiving element face each other in an optical path reciprocating on the tape running path via a mirror. Video deck. 7. The video deck according to claim 1, wherein the current control means is connected to the light emitting element in series and connected to each other in parallel. A video deck comprising two current control resistors, wherein a current supplied to the light-emitting element is controlled by controlling conduction of the current control resistors.