JPS6153792B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display device that displays the remaining amount of magnetic tape by detecting rotation of a reel shaft.

In a display device configured to display the remaining amount of magnetic tape on a display board having a large number of display elements such as liquid crystals arranged in parallel, the accuracy is determined by the number of display elements. The present invention aims to provide a display device whose accuracy increases as the remaining amount of magnetic tape decreases, and will be described in detail below with reference to the illustrated embodiments.

In the figure, 1 and 2 are the take-up reel shaft and supply reel shaft of the tape recorder, respectively, and 3 and 4 are rotation detectors that output signals such as pulses according to the rotational speed of the take-up reel shaft 1 and the supply reel shaft 2. 5 is a tape remaining amount detection circuit that outputs a signal indicating the remaining amount of magnetic tape by comparing the signals obtained from the rotation detectors 3 and 4; 6 is a large number of display elements 7 such as liquid crystals; This is a display board having a tape amount display section 8 arranged in parallel and first and second scale display elements 9 and 10 for indicating the scale of the tape amount display section 8. The indicated value of the first scale display element 9 is set to be twice that of the second scale display element 10. Reference numeral 11 indicates a first scale display element 7 for driving the display element 7 and the first and second scale display elements 9 and 10 in accordance with the signal from the tape remaining amount detection circuit 5.
The display element driving circuit has output terminals T ₁ to T ₆₀ and is configured such that an output signal from the output terminal T ₁ to an output terminal indicating the remaining amount of tape is at H (high) level. 12 is a second display element drive circuit that drives the display element 7 according to the signal from the tape remaining amount detection circuit 5, and output terminals S ₁ to
_S60 , and the output signal from the output terminal _S1 to the output terminal indicating the remaining amount of tape is set to H level. In such a circuit, when the output terminal T1 to the nth output terminal _To of the first display element drive circuit ₁₁ are at H level in response to the signal from the tape remaining amount detection circuit 5, From the output terminal S ₁ of the 2-display element drive circuit 12
It is set so that up to the 2nth output terminal _T2o is at H level. 13 and 14 are 1/2m+1st (1/2×60+1 in the embodiment) of the total number of output terminals m (60 in the embodiment) of the display element drive circuit 11 in Table 1.
= 31) Inverter circuit whose input is the output of the output terminal, A ₁ to A ₆₀ are the inverter circuits 14
AND circuits that receive output signals from the second display element drive circuit 12; B ₁ to _{B 60} receive output signals from the AND circuits A ₁ to A ₆₀ and the first display element drive circuit 11; The output terminals are connected to drive the display elements C ₁ to C ₆₀ , respectively. Further, when the output of the output terminal T ₃₁ of the first display element driving circuit 11 is at H level, the first scale display element 9 is driven, and when the output is at L level, the signal is inverted by the inverter circuit 13. The second scale display element 1
Connected to drive 0.

The present invention is constructed as described above, and its operation will be explained next. When a cassette tape is loaded into the cassette insertion section and a playback operation is performed, the take-up reel shaft 1 and the supply reel shaft 2 start rotating, and the rotation detectors 3 and 4 detect the reel shafts 1 and 2.
A signal such as a pulse is output according to the rotation speed of the motor. As a result, a signal indicating the remaining amount of tape is output from the tape remaining amount detection circuit 5, and the output signal is inputted to, for example, an output terminal of the first display drive circuit 11.
An H level signal is output from T ₁ to T ₃₅ , and the second
The display element drive circuit 12 has 2×35=70 output terminals.
All outputs of _S1 to _S60 become H level. In this state, the output terminal T ₃₁ of the first display element drive circuit 11
Since the output of
4, the L (low) level signal is sent to the AND circuit.
It is input to the input terminals _A1 to _A60 . Therefore,
Even when the output signal from the second display element drive circuit 12 is at H level, the outputs of the AND circuits A ₁ to A ₆₀ are all at L level. In such a state, the outputs of the OR circuits B ₁ to B ₃₅ to which H level signals are input from the output terminals T ₁ to T ₃₅ of the first display element drive circuit 11 become H level, and the display elements C ₁ to Drive the C ₃₅ to light up. In this case, the number of display elements 7 is 60, and the scale value of the first scale display element 9 is set to 30 minutes, so the time per display element 7 is
30 seconds, and it can be seen that in this state there is 30 seconds x 35, or 17 minutes and 30 seconds of tape remaining. As the playback operation progresses, the display elements C ₃₅ , C ₃₄ . . . turn off in order to indicate that the remaining amount of tape is decreasing.

When the above-described operation is performed and the display element C ₃₁ is turned off, that is, the first display element drive circuit 11
When the output of the output terminal _T31 becomes L level, one of the signals inputted to the AND circuits _A1 to _A60 all becomes H level. Also, at this time, the second display element drive circuit 1
The outputs of 2 are 2×30=60, that is, the outputs of the output terminals S ₁ to S ₆₀ are at H level, and the AND circuits A ₁ to A ₆₀ output signals at H level. Therefore, the outputs of the OR circuits B ₁ to _{B 60} to which the signals are input become H level, and the display elements C ₁ to C ₆₀ are driven to light up. Furthermore, since the output of the output terminal _T31 of the first display element drive circuit 11 is at L level, the first scale display element 9 is turned off.
The second scale display element 10, to which the inverted H-level signal is applied by the inverter circuit 13, is driven to light up. In this case, display element 7
is 60, and the second scale display element 10
Since the scale value is set to 15 minutes, the time for each display element 7 is 15 seconds, and it can be seen that in this state, 15 seconds x 60, that is, 15 minutes of tape remains. As the playback operation progresses, the display elements C ₆₀ , C ₅₉ . . . turn off in order to indicate that the remaining amount of tape is decreasing.

In this embodiment, the number of display elements 7 is set to 60, but it is of course possible to increase or decrease the number, and although the case where the number of scale display elements is two is described, it is also possible to increase the number. Furthermore, although the display and scale display are switched when the display on the display board 6 becomes half, it is also possible to switch when the display becomes one-third or one-fourth.
Then, the tape remaining amount detection circuit 5, the first display element drive circuit 11, the second display element drive circuit 12, the inverter circuits 13 and 14, the AND circuits _A1 to _A60 , and OR
Although an embodiment of the present invention has been shown that is constituted by the circuits B ₁ to _{B 60} , the display device of the present invention can be constructed very easily if the arithmetic and control processing is performed by a microcomputer.

As explained above, the display device of the present invention switches the display and scale value on the display board when the remaining amount of tape becomes low to increase the precision per display element, so that the remaining amount of tape can be accurately displayed. Moreover, it can be recognized reliably, and is particularly effective when recording is being performed.

[Brief explanation of the drawing]

The drawing shows an embodiment of the display device of the present invention. Explanation of main drawing numbers, 1... Take-up reel shaft, 2...
...Supply reel shaft, 5...Tape remaining amount detection circuit, 6
... Display board, 7 ... Display element, 9 ... First scale display element, 10 ... Second scale display element, 1
1...First display drive circuit, 12...Second display element drive circuit.

Claims (1)

[Claims] 1. A tape remaining amount detection circuit that outputs a signal indicating the remaining amount of magnetic tape by detecting the rotation of the reel shaft, a tape amount display section in which a large number of display elements such as liquid crystals are arranged in parallel, and the tape amount. A display board having a plurality of scale display sections for instructing the scale of the display section, and a display element drive circuit that drives a display element constituting the tape amount display section of the display board in response to a signal from the remaining tape amount detection circuit. When the remaining amount of tape reaches a predetermined value, the scale display section of the display board is switched, and the display element of the tape amount display section is switched and driven in response to the scale switching. tape recorder display device.