JPH0489521A - Detecting device of rotation - Google Patents

Abstract

PURPOSE:To reduce a current consumed by a light-emitting element and to enable measurement of the amount of rotation of a rotary plate by making the light-emitting element emit a light intermittently by a pulse signal. CONSTITUTION:A light-emitting element driver 3, which is driven intermittently by a control pulse signal, makes a current flow from a power source 5 to a light-emitting element 2 and makes the element 2 emit a light intermittently. An output light signal from the element 2 is passed through a transmitting slit in a rotary disk and applied to a light-sensing element 6. An output signals of the element 6 by this applied light is a burst-shaped pulse signal. A synchronous detector 9 turns the pulse signal into a rectangular wave by a delay circuit 8, and a rotation amount detector 10 counts the leading or trailing edge of the rectangular wave from the detector 9 and thereby measures the amount of rotation of the rotary disk 1. By executing measurement by making the light-emitting element emit the light intermittently, in this way, the amount of rotation of the rotary disk can be measured with small consumption of power.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotation detection device that detects the amount of rotation of a rotating body by photoelectric conversion.

2. Description of the Related Art In recent years, rotation detection devices that optically detect the amount of rotation of a rotating plate such as a reel stand have been widely used as detection means for tape counters in audio tape recorders, video tape recorders, and the like.

A conventional rotation detection device will be described below with reference to the drawings.

FIG. 7 is a block diagram of a rotation detection device used in a conventional tape counter. In the figure, 1 is a rotating disk attached to the reel shaft and has a slit 1a for detecting the amount of rotation of the reel, and 2 is a slit (la) on the rotating disk.
5 is a power source for the light emitting element 2,
3 is a light emitting element driver that supplies current from the power source 5 to the light emitting element 2; 16 is a drive control circuit that controls the light emitting element driver 3; 6 is a drive control circuit for controlling the light emitting element 2; A light receiving element that receives light and converts it into an electrical signal, 7
1 is an amplifier that amplifies the signal from the light receiving element, and 10 is a rotation amount detector that counts rising or falling edges of the signal from the amplifier 6 to detect the amount of rotation.

FIG. 8 is a signal waveform diagram of the main part of the block in FIG. 7. In FIG. 8, the wave (L) is the signal waveform of the control signal of the drive control circuit 16, the waveform (M) is the current waveform flowing through the light emitting element 2, and the waveform (N) is the output signal of the light receiving element 6 amplified by the amplifier 7. This is the output signal waveform.

The operation of the rotation detection device configured as described above will be described below. Immediately before the rotating disk 1 starts rotating, a control signal is sent from the drive control circuit 16 to the light emitting element driver 3 to cause current to flow through the light emitting element 2. The light emitting element 2 emits light when a current flows therethrough. The timing is shown in waveforms (L) and (M). The light receiving element 6 outputs a rectangular wave signal of waveform (N) in synchronization with the rotation of the rotating disk 1. T1 is light emitting element 2
T is the time that the optical signal from T passes through the slit 1a.
2 is the time during which the optical signal is interrupted by the rotating disk.

The output signal of the light receiving element 6 is amplified by an amplifier 7 and inputted to a rotation amount detector 10. The rotation amount detector 10 detects the amount of rotation of the rotating disk by counting the rise or fall of the input rectangular wave.

Problems to be Solved by the Invention In such conventional rotation detection devices, current is constantly passed through the light-emitting element during rotation, so in small devices such as portable tape recorders, the light-emitting element consumes a lot of power and the length of the device increases. This poses a problem in terms of time usage and miniaturization of equipment, and particularly in small equipment such as portable tape recorders, the battery life is short.

The present invention solves the above problems, and aims to provide a rotation detection device that detects the amount of rotation of a reel with low power consumption. ' Means for Solving the Problems In order to achieve the above object, the present invention includes a pulse generating means for outputting a drive control signal of a light emitting element driver as a pulse;
It has a pulse period adjuster that changes the pulse interval of the pulse generating means according to the rotation mode of the rotating disk, a light emitting element that is intermittently lit by a light emitting element driver controlled by a pulse signal, and a slit or a reflecting plate. A rotating disk attached to the reel shaft, a light receiving element arranged to receive light from the light emitting element through a slit in the rotating disk or a reflecting plate, and an intermittent pulse signal from the light receiving element to determine the amount of rotation of the rotating disk. It is equipped with a rotation amount detection means for measuring.

The pulse period adjuster is arranged to change the pulse period of the pulse generating means in accordance with the selected rotation mode.

In addition, the rotation detection means measures the amount of rotation of the rotating disk by synchronous detection of the light receiving element output pulse with the pulse of the pulse generating means, envelope detection of the light receiving element output pulse burst, and measurement of the light receiving element output pulse period. It is arranged so that

Effect of the Invention With the above-described configuration, the present invention is capable of reducing the current consumption of the light emitting element by lighting the light emitting element intermittently using a pulse signal, and measuring the amount of rotation.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a rotation detection device according to a first embodiment of the present invention. Components having the same functions as those of the conventional example are given the same reference numerals, and explanations thereof will be omitted. In FIG. 1, numeral 4 represents a pulse generating means for controlling the light emitting element driver 3;
An oscillator is used.

Reference numeral 17 denotes a mode switch for selecting the use mode of the tape recorder, and selects each mode of playback, long-time playback, playback fast forward, playback rewind, and fast forward 9 rewind. Reference numeral 18 denotes a pulse period adjuster that changes the pulse period of the pulse excavation means according to each of the above-mentioned modes. Reference numeral 8 denotes a delay circuit for delaying the output signal of the pulse generating means 4. Reference numeral 9 denotes a synchronous detector that detects the output signal of the amplifier 7 using the pulse signal of the delay circuit 8. Delay circuit 8, synchronization detector 9, and rotation amount detector 10
This constitutes the rotation amount detection means 14.

FIG. 4 is a signal waveform diagram of the main part of the block diagram of FIG. 1.

In FIG. 4, the waveform (A) is the output control signal waveform of the pulse generating means 4, the waveform (B) is the current waveform flowing through the light emitting element 2, the waveform (C) is the output signal waveform of the amplifier 7, and the waveform (D) is the delay waveform. Output signal waveform of circuit 8, waveform (E) is synchronous detector 9
T1 is the time during which the output light beam of the light emitting element can pass through the slit of the rotating disk 1, T2 is the time during which it is masked and blocked, T3 is the delay time of the delay circuit 8, and T4 is the pulse generation means 4. The pulse width of the output control signal, T5, is the period of the same pulse. Here, it is assumed that T3<T4. The pulse period of the pulse generating means 4 is adjusted according to the selected mode of the tape recorder, and the pulse period is adjusted so that at least several pulses of light can pass through one slit from the light emitting element 2 to the light receiving element 6. Adjust by. That is, during long-time playback, the reel rotates at a slower speed, so the pulse cycle is made longer, and during fast-forwarding and rewinding, the reel rotates at a higher speed, so the pulse cycle is made shorter.

The operation of the rotation detector of the present invention will be explained below with reference to FIGS. 1 and 4.

In response to the selection of the mode switch 17, a signal is given from the pulse period adjuster 18 to the pulse generating means 4 to generate a pulse with a period corresponding to the operation mode, and the pulse generating means 4
A control pulse signal of waveform (A) is obtained from . The light emitting element driver 3 is intermittently driven by a control pulse signal from the pulse generating means 4, and the light emitting element driver 3 is driven intermittently by the control pulse signal from the pulse generating means 4, and the light emitting element power supply 5 is supplied to the light emitting element 2.
A current is caused to flow intermittently as shown in the waveform (B), and the light emitting element 2 is intermittently lit. In this case, the power consumption of the light emitting element 2 is T4/T compared to the case where current is constantly flowing.
Reduce to 5. The output optical signal from the light emitting element 2 passes through a transmission slit on the rotating disk and is irradiated onto the light receiving element 6. The output signal of the light receiving element 6 due to this irradiation light is amplified by the amplifier 7. The output signal of the amplifier 7 repeatedly blocks and passes light from the light emitting element as the rotating disk 1 rotates, and becomes a burst-like pulse signal shown in waveform (C).

The synchronous detector 9 detects the output pulse signal of the amplifier 7 in synchronization with the rising edge of the output pulse signal of the delay circuit 8 (waveform (D)), thereby generating a rectangular wave shown in waveform (E). The rotation amount detector 10 measures the amount of rotation of the rotating disk 1 by counting the rising or falling edges of this rectangular wave from the synchronous detector 9.

As described above, according to the rotation detection device of the first embodiment of the present invention, the light emitting element is lit intermittently rather than continuously, and the light burst train passing through the slit of the rotating disk attached to the reel shaft is synchronously detected. Since it is arranged to measure the amount of rotation of the rotating disk with low power consumption.

FIG. 2 is a block diagram of a rotation detection device according to a second embodiment of the present invention. Components having the same functions as those in the above embodiment are given the same reference numerals, and explanations thereof will be omitted.

2 In FIG. 2, reference numeral 11 denotes a detector for detecting the envelope of the burst-like pulse signal output from the amplifier 7. 12 is a Schmitt trigger circuit that shapes the output signal waveform of the wave detector 11. The detector 11, the Schmitt trigger circuit 12, and the rotation amount detector 10 constitute a rotation amount detection means 15.

FIG. 5 is a signal waveform diagram of the main part of the block diagram of FIG. 2.

In FIG. 5, the waveform (F) is the output control signal waveform of the pulse generating means 4, the waveform (G) is the current waveform flowing through the light emitting element 2, the waveform (H) is the output signal waveform of the amplifier 7, and (J) is the envelope. The output signal waveform of the wave detector 11 and (K) are the output waveforms of the Schmitt trigger circuit 12.

Hereinafter, the operation of the rotation detection device of the present invention will be explained using FIGS. 2 and 5.

The operations from the pulse generating means 4 to the amplifier 7, the mode switch 17, and the pulse period adjuster 18 are the same as in the first embodiment, so their explanation will be omitted. The output signal of the amplifier 7 is subjected to envelope detection by the envelope detector 11 as shown by the solid line in waveform (J) in FIG.

The Schmitt trigger circuit 12 shapes the envelope-detected signal as shown in waveform (K) to generate a rectangular wave. The rotation amount detector 10 measures the amount of rotation of the rotating disk 1 by counting the rising or falling edges of the rectangular wave from the Schmitt trigger circuit 12.

As described above, according to the rotation detector of the second embodiment of the present invention, as in the first embodiment, the light emitting element is lit intermittently to reduce power consumption, and the light burst passing through the rotating disk slit is enveloped. Since the arrangement is such that line detection is performed, rectangular shaping is performed, and counting is performed, the amount of rotation of the rotating disk can be measured with a simple configuration.

FIG. 3 is a block diagram of a rotation detection device according to a third embodiment of the present invention. Components having the same functions as those in the above embodiment are given the same reference numerals, and explanations thereof will be omitted.

In FIG. 3, reference numeral 13 denotes rotation amount detection means for inputting the burst-like output pulse signal of the amplifier 7 and measuring the rotation amount. FIG. 6 is a flowchart showing the operation of the rotation amount detection means 13 of FIG.

Hereinafter, the operation of the rotation detection device of the present invention will be explained using FIGS. 3 and 6.

The operation from the pulse generating means 4 to the amplifier 7 and the mode switch 17. The pulse period adjuster 18 is the same as in the first embodiment, so its explanation will be omitted. The burst-like output pulse signal of the amplifier 7 is input to the rotation amount detection means 13, and the sixth
The amount of rotation of the rotating disk is measured according to the flowchart in the figure. Okay, step 1. In step 2, the signal from the amplifier 7 is input, and the level of the signal, that is, high or low, is identified. If high, proceed to step 3; if low, return to step 1. In step 3, the pulse period generated by the pulse generating means 4 is stored in advance, and the process waits for the pulse period, and then the process proceeds to step 4. Step 4. In step 5, the signal from the amplifier 7 is input, and high and low signals are identified. If high, proceed to step 6; if low, return to step 1. Step 6 waits for a pulse-period period and proceeds to step 7. In steps 7 and 8, the signal from the amplifier 7 is input, and high and low signals are identified. If it is low, proceed to step 9; if it is high, return to step 6. Step 9 waits for a pulse-period period and proceeds to step 10. In steps 10 and 11, the signal from the amplifier 7 is input, and high and low signals are identified.

If it is low, the process advances to step 12; if it is high, the process returns to step 6. In step 12, the counter value for the amount of rotation is counted such that it increases when the rotating disk rotates in the normal direction and decreases when the rotating disk rotates in the reverse direction, and then returns to step 1 and repeats the above steps. Steps 1 to 5 are the parts for detecting the section where the optical signal from the light emitting element 2 to the light receiving element 6 changes from the blocking state to the passing state due to the rotation of the rotating disc 1. This is a part that detects the section where the optical signal from the light emitting element 2 to the light receiving element 6 changes from the passing state to the blocking state due to the rotation of the light emitting element 2.

As described above, according to the rotation detection device of the third embodiment of the present invention, as in the first embodiment, the power consumption of the light emitting element is reduced, and the output signal of the light receiving element is amplified to produce taburst-like pulses. A rotation amount detection means for measuring the pulse interval of the signal is provided,
The amount of rotation of the rotating disk can be measured by distinguishing between blocking and passing of optical signals caused by the rotation of the rotating disk.

In addition, in the first to third embodiments described above, when the rotational speed of the reel increases during fast forwarding and rewinding, the light emitting element is always turned on when the pulse signal cannot pass through the slit 1a on the rotating disk 1 in a burst shape. Turn on the first and second
In the embodiment, the output signal of the amplifier 7 is directly input to the rotation amount detector 10, and in the third embodiment, the internal operation of the rotation amount detection means 13 is changed to the same operation as the conventional rotation amount detector 10. .

In addition, in the third embodiment, in order to detect the rotation amount of the rotating disk inside the rotation amount detection means 13, two pulse inputs are used to determine whether the optical signal passes or is blocked, and whether the optical signal is passed or not. However, it is not limited to two times.

Further, in the first and second embodiments, the pulse generating means 4, the pulse period adjuster 18, and the rotation detector 10 are one microprocessor, and in the third embodiment, the pulse generating means 4 and the pulse period adjuster 18 are one microprocessor. The rotation amount detection means 13 and the rotation amount detection means 18 can be processed by one microprocessor.

Although an example has been described in which the rotating disk 1 is provided with the slits 1a, the same effect can be obtained by providing a reflective plate instead of the slits.

Effects of the Invention As described above, the present invention includes a rotation amount detection means that intermittently causes a light emitting element provided to detect the rotation amount of the rotating disk to emit light and measures the rotation amount from a burst-like pulse signal. Therefore, the amount of rotation of the rotating disk can be measured without constantly passing current through the light emitting element, and the power consumption in the light emitting element is reduced in proportion to the duty ratio of the pulses of the pulse generating means, reducing the length of the equipment. It is possible to provide a rotation detection device with low power consumption that is suitable for time use and miniaturization.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a rotation detection device according to a first embodiment of the present invention, FIG. 2 is a block diagram of a rotation detection device according to a second embodiment, and FIG. 3 is a block diagram of a rotation detection device according to a third embodiment. 4 is a signal waveform diagram of the main block part of the rotation detection device of the first embodiment, FIG. 5 is a signal waveform diagram of the main block part of the rotation detection device of the second embodiment, and FIG. FIG. 7 is a flowchart showing the operation of the rotation detecting means of the third embodiment, FIG. 7 is a block diagram of a conventional rotation detecting device, and FIG. 8 is a signal waveform diagram of a main block of the rotation detecting device. 1... Rotating disk, 1a... Slit, 2.
...Light emitting element, 4...Pulse generating means, 6.
... Light receiving element, 7... Amplifier, 8... Delay circuit, 9... Synchronous detector, 10... Rotation amount detector,
11... Envelope detector, 12... Schmidt trigger circuit, 13. 14. 15... Rotation amount detection means. Name of agent: Patent attorney Shigetaka Awano, 1 person rotation 8th edition pickpocket *, % Child light emitting element driver' Pulse registration l19p5 Rinko Hakumitsu 4?lFJ Handy motor switch α coe for rotation

Claims (5)

[Claims] (1) A rotating disk having a slit or a reflecting plate, a light emitting element disposed on the rotating disk so as to face a surface having the slit or reflecting plate, and a pulse generating means for causing the light emitting element to emit light intermittently. a pulse period adjuster for varying the pulse period of the pulse generating means; a light receiving element arranged to receive light from the light emitting element through a slit or a reflecting plate of the rotating disk; A rotation detection device comprising an amplifier for amplifying an output signal and rotation amount detection means. (2) The rotation detecting device according to claim 1, wherein the pulse period adjuster is arranged to change the pulse period of the pulse generating means according to the selected rotation mode. (3) The rotation detection device according to claim 1 or 2, wherein the rotation amount detection means is arranged to measure the rotation amount by detecting the output signal from the amplifier by synchronously detecting the signal from the pulse generation means. (4) Claim 1 or 2, wherein the rotation amount detection means is arranged to detect the envelope of the output signal from the amplifier and measure the rotation amount.
The rotation detection device described. (5) The rotation detection device according to claim 1 or 2, wherein the rotation amount detection means is arranged to measure the rotation amount by measuring the pulse period of the output signal from the amplifier.