JPH05173234A - Film winding device - Google Patents

Abstract

PURPOSE:To provide a film winding device which is capable of winding a film from the rotational quantity of a motor in an accurate manner with simple constitution. CONSTITUTION:A control circuit 13 reads the corrective amount of the amplification factor of an AC amplifier 6 and the threshold value of a comparator 7 which are stored in an EEPROM 12 according to the pulse interval of the pulse to be inputted from the comparator 7 (speed of a DC brush motor) and the battery voltage detected data detected by a battery voltage detecting circuit 10 are read, the feedback is implemented, and correction is made for the threshold values of the AC amplifier 6 and the comparator 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film winding device for a camera.

[0002]

2. Description of the Related Art A conventional film winding device for a camera is
The winding amount of the film was controlled by counting the feed holes provided in the film.

A specific method of detecting the feed hole is as follows. A reflection type photo interrupter is provided on one side so as to sandwich the sprocket hole provided in the film, and a black member for absorbing the light emitted by the photo interrupter is provided on the other side. Then, a series of film feed holes reflect or transmit the light emitted by the light emitting diode each time the feed hole provided in the film passes between the black member and the reflection type photo interrupter, and the light receiving element receives the light. The feed hole was detected by.

[0004]

In the above, since a photo interrupter or the like is used for detecting the film winding amount, the number of parts is large, the cost is high, and the shape of the photo interrupter is not small. A small camera has a problem that it is difficult to obtain a storage space.

An object of the present invention is to provide a film winding device capable of accurately winding a film with a simple structure.

[0006]

The present invention achieves the above object by providing control means for controlling the amplification factor of the amplifier and / or the set level of the comparison means in accordance with the rotation speed of the DC brush motor. There is.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case in which the present invention is used for a film winding and rewinding operation of a camera will be specifically described below based on an embodiment shown in the drawings.

In FIG. 1, reference numeral 1 denotes a motor bridge circuit, which comprises a DC brush motor 2, diodes 3 to 3, transistors 4 to 4 and a resistor 5, and controls bidirectional rotation of the DC brush motor 2. The DC brush motor 2 operates to wind and rewind a film (not shown). The resistor 5 is for detecting brush noise generated by the rotation of the DC brush motor 2. An AC amplifier 6 constitutes an amplifier. Reference numeral 7 is a comparator which constitutes a comparing means, and 8 is a counter which makes a coefficient of brush noise. Reference numeral 9 is a battery serving as a power source, and 10 is a battery voltage detection circuit that detects the voltage of the battery power source 9. 11
Is a temperature detection circuit that detects the ambient temperature. Reference numeral 12 denotes a memory circuit, which is an EEPROM in this example and stores the following data. The rotation amount data of the DC brush motor 2 and the brush noise generated from the DC brush motor 2 with respect to a predetermined (one frame and three frames) feed amount of the film, which changes as the film is wound up, vary depending on each DC brush motor. Therefore, data indicating the amplification factor of the AC amplifier 6 according to the DC brush motor 2 used in the present embodiment, data indicating the threshold value of the comparator 7, and the AC amplifier 6 according to the battery voltage and temperature changes. Correction data of the amplification factor and the threshold value of the comparator 7, data for instructing the timing of braking the DC brush motor 2 according to the winding amount of the film, that is, the rotation of the DC brush motor 2, and at the time of normal operation. The data and the like indicating the allowable range of the pulse interval of the brush noise of are stored. Reference numeral 13 is a control circuit which constitutes a control means, and is C
It comprises a PU, a ROM, a RAM, etc., and controls the amplification factor of the AC amplifier 6 and / or the threshold value of the comparator 7 by the outputs of the battery voltage detection circuit 10 and the temperature detection circuit 11, and also controls various operations. Also do.
The counter 8 and the control circuit 13 constitute a winding control means. A drive control circuit 14 turns on / off the transistors 4 to 4 according to an input signal from the control circuit 13.

Next, the operation will be described with reference to FIG. When the control circuit 13 detects the activation input signal by operating the external switch, the following operation is started. When the film is completely rewound by operating the rewind switch or film winding operation (step 2a), the film rewinding operation is performed (step 2b), and when the back cover is closed (step 2c), the film is rewound. When the shutter button is operated (step 2e), exposure processing is performed (step 2f), and then one frame winding processing is performed (step 2g). ).

A specific processing operation of the one-frame winding process (step 2g) will be described with reference to FIGS.
Now, it is assumed that the number of films wound up is stored in the RAM in the control circuit 13. When the exposure process is completed by operating the shutter switch, the presence or absence of a film is detected by a film detection device (not shown) (step 3a), and the AC amplifier 6 and the comparator 7 for detecting brush noise of the DC brush motor 2 are detected. The correction process 1 is performed (step 3b).

The specific processing of step 3b will be described with reference to FIG. The temperature detection circuit 11 detects the ambient temperature (step 4a), and the battery voltage detection circuit 10 detects the battery voltage (step 4b). Next, the control circuit 13 stores the amplification factor of the AC amplifier 6 and the setting data of the threshold value of the comparator 7 which are stored in advance in accordance with the DC brush motor 2 to be used, based on the above detection outputs.
12 is read (step 4c), and the amplification factor of the AC amplifier 6 and the threshold value of the comparator 7 are corrected and set based on the read setting data (steps 4d, 4).
e). For example, the amplification factor of the AC amplifier 6 and the threshold value of the comparator 7 are increased as the ambient temperature moves away from room temperature (about 25 ° C.), and when the battery voltage is low, the AC
Correction is performed by increasing the amplification factor of the amplifier 6 and the threshold value of the comparator 7.

After the operation of step 3b is completed, the control circuit 13
Clears the counter 8 and also clears the flag for correcting the winding amount (step 3c). Next, the control circuit 13 reads out the number of wound films stored in the internal RAM (step 3d). From the read number of films, the rotation amount data of the DC brush motor 2 required to wind one frame is read from the EEPROM 12 (step 3).
e). Drive control circuit 1 according to the output from control circuit 13
4, a drive output of the DC brush motor 2 is generated, the desired transistors 4 to 4 are turned on to rotate the DC brush motor 2, and film winding is started (step 3).
f). The brush noise pulse generated by the rotation of the DC brush motor 2 is amplified by the AC amplifier 6 and input to the comparator 7. The comparator 7 generates an output of one pulse each time it detects a brush noise pulse equal to or more than the threshold value, and this output is input to the counter 8 and the control circuit 13. Then, in order to determine whether the brush noise pulse generated from the DC brush motor 2 is normally output, the allowable range data of the pulse interval of the brush noise pulse generated in the film winding of this example, which is stored in the EEPROM 12 in advance, is stored. Read out (step 3g). When the back cover is opened during the winding operation while monitoring the state of the back cover (step 3h), the control circuit 13 interrupts the winding process and stops the rotation of the DC brush motor 2. (Step 3o). Next, in order to accurately detect the brush noise of the DC brush motor 2, the AC amplifier 6
And the correction process 2 of the comparator 7 is performed (step 3i).

Here, the specific operation of step 3i will be described with reference to FIG. The control circuit 13 uses the pulse interval (step 5a) of the pulses input from the comparator 7 and the battery voltage data (step 5b) detected by the battery voltage detection circuit 10 to determine the amplification factor of the AC amplifier 6 stored in the EEPROM 12 and the comparator 7. The correction amount data with the threshold value is read (step 5c), and feedback is applied to correct the amplification factor of the AC amplifier 6 and the threshold value of the comparator 7 (steps 5d and 5e). That is, since the magnitude of the brush noise changes according to the rotation speed (pulse interval) of the DC brush motor 2, the correction is performed to accurately detect the brush noise. In particular,
When the rotation of the DC brush motor 2 becomes faster, the AC amplifier 6
The correction is performed to reduce the amplification factor and the threshold value of the comparator 7. Next, a winding amount correction process is performed (step 3j).

The specific operation of step 3j will be described with reference to FIG. The control circuit 13 determines whether the interval between pulses input from the comparator 7, that is, the rotation speed of the DC brush motor 2 is stable (step 6a). If the pulse interval is stable, it is determined whether the winding amount correction flag is 1 (step 6b). Winding amount correction flag is 1
If not, the EEPROM 12 is accessed from the film winding amount data read in step 3e, the battery voltage detected in step 3i and the ambient temperature detected in step 3b, and the DC brush motor 2 is braked. Is read (steps 6c and 6d), and the rotation amount data is corrected (step 6e). In other words, the DC brush motor 2 rotates to some extent due to inertia even after the brake is applied, and this rotation amount changes depending on the film winding amount, temperature, and battery voltage. It corrects the quantity data. Specifically, the timing to apply the brake is delayed when the winding amount increases, and the timing to apply the brake is advanced when the battery voltage is high, and the mechanical load increases as the difference between the ambient temperature and the room temperature (about 25 ° C) increases. Since it increases, delay the timing to apply the brake. Next, the winding amount correction flag is set to 1 (step 6f). A winding amount correction flag is provided in order to perform the winding amount correction process only once for each winding process.

Then, the previously read permissible range data of the pulse interval is compared with the pulse interval of the brush noise pulse generated from the DC brush motor 2 and there is no abnormality in the pulse width (step 3k). When the number of pulses of the rotation amount data corrected in 3j is counted (step 3m), an output for applying a brake is generated from the control circuit 13, and, for example, two transistors 4 in the lower stage,
4 is turned on to brake and stop the DC brush motor 2 (steps 3n, 3o). At this time (step 3n), the control circuit 13 stores the number obtained by adding 1 to the stored number of films in the internal RAM as the number of wound films. If the counter 8 does not count the number of pulses of the rotation amount data corrected in step 3j (step 3
m), the process returns to step 3h again, and the same operation as above is performed. Further, when the step 3k is operated, the brush noise pulse interval generated from the DC brush motor 2 is set to the EEPROM.
When the pulse interval read from 12 is out of the allowable range, it is determined that the film has been wound up to the end, the DC brush motor 2 is stopped (step 3p), and the rewinding process is performed (step 3q). That is, when the film is wound up to the end, the load applied to the DC brush motor 2 becomes excessive and the film does not rotate. Therefore, the film is rewound when the pulse interval of the brush noise pulse becomes larger than the allowable range.

Next, a specific processing operation of the three-frame winding process in step 2d of FIG. 2 will be described with reference to FIG. When the control circuit 13 detects a start input signal generated by closing the back cover after loading the film, the film detecting device (not shown) detects the presence or absence of the film (step 7a), and the DC brush motor 2
The correction processing 1 of the AC amplifier 6 and the comparator 7 is performed to detect the brush noise of (step 7).
b). The correction processing 1 (step 7b) of the AC amplifier 6 and the comparator 7 is the same as the above description (see FIG. 4).
After the operation of step 7b is completed, the control circuit 13 causes the counter 8
And the flag for correcting the winding amount are also cleared (step 7c). The rotation amount data of the DC brush motor 2 required for winding three frames is read from the EEPROM 12 (step 7d). A drive output is generated from the drive control circuit 14 by the output from the control circuit 13, and the DC brush motor 2 is rotated to start film winding (step 7).
e).

Brush noise pulses generated by the rotation of the DC brush motor 2 are amplified by the AC amplifier 6,
It is input to the comparator 7 and generates an output of one pulse each time a brush noise pulse equal to or higher than the threshold value is detected, and this output is input to the counter 8 and the control circuit 13. Then, in order to determine whether or not the brush noise pulse generated from the DC brush motor 2 is normally output, EEP is performed in advance.
The permissible range data of the pulse interval of the brush noise pulse generated in the film winding of this example stored in the ROM 12 is read (step 7f). When the back lid is opened during the winding operation while monitoring the state of the back lid (step 7g), the control circuit 13 interrupts the winding operation and stops the rotation of the DC brush motor 2. (Step 7n). If the back cover is closed, then correction processing 2 of the AC amplifier 6 and the comparator 7 is performed in order to accurately detect brush noise of the DC brush motor 2 (step 7h). The operation of the correction process 2 (step 7h) of the AC amplifier 6 and the comparator 7 is similar to the above (see FIG. 5). Next, a winding amount correction process is performed (step 7i). The operation of the winding amount correction process (step 7i) is also the same as the above (see FIG. 6). Then, by comparing the read permissible range data of the pulse interval with the pulse interval of the brush noise pulse generated from the DC brush motor 2, there is no abnormality in the pulse width (step 7j), and the counter 8 rotates the rotation corrected in step 7i. When the number of pulses of the quantity data is counted (step 7k), a brake output is generated from the drive control circuit 14 by the output from the control circuit 13, causing the transistors 4 to 4 to perform a predetermined operation to brake the DC brush motor 2 and stop it. (Step 7m,
7n). If the counter 8 does not count the number of pulses of the rotation amount data corrected in step 7i (step 7
k) Then, the process returns to step 7g again and the same operation as described above is performed. In addition, when the step 7j is operated, the EEPROM is first
From the pulse range allowable range data read from 12,
When the brush noise pulse interval generated from the DC brush motor 2 deviates, it is judged that the film cannot be properly loaded, and for example, a warning sound is generated and a loading error process such as displaying is performed (step S). 7o), brake the DC brush motor 2 and stop it (step 7n).

Next, the operation of the film rewinding process will be described with reference to FIG. When the rewinding switch is operated or the film is terminated and the film winding by the DC brush motor 2 is stopped, the presence or absence of the film is detected by the film detecting device (not shown) (step 8).
a), correction processing 1 of AC amplifier 6 and comparator 7
Is performed (step 8b). The operation of the correction process 1 (step 8b) of the AC amplifier 6 and the comparator 7 is similar to the above (see FIG. 4). The control circuit 13 drives the DC brush motor 2 to start film rewinding (step 8c). Similarly to the above, the brush noise generated from the DC brush motor 2 is amplified by the AC amplifier 6, is input to the comparator 7, and generates one pulse each time a brush noise pulse above the threshold value is detected,
This output is input to the counter 8 and the control circuit 13.
When the back cover is opened during the winding operation while performing the processing described later while monitoring the state of the back cover (step 8d),
The control circuit 13 interrupts the winding process and stops the rotation of the DC brush motor 2. (Step 8i). If the back cover is closed, then correction processing 2 of the AC amplifier 6 and the comparator 7 is performed to detect brush noise of the DC brush motor 2 (step 8e). The operation of the correction process 2 (step 8e) of the AC amplifier 6 and the comparator 7 is the same as above. (See Figure 5). When the pulse interval of the comparator 7 input to the control circuit 13, that is, the pulse interval of the brush noise pulse changes rapidly (steps 8f and 8g), the control circuit 13 finishes the rewinding of the film and the load applied to the DC brush motor 2 is reduced. When it is determined that the problem has been resolved, the DC brush motor 2 is braked (step 8h) and stopped (step 8i). That is, when the rewinding is completed, the load applied to the DC brush motor 2 is drastically reduced, so that the pulse interval of the brush noise pulse becomes small, and it is determined that the rewinding is completed at this time.

In the above embodiment, the pulse interval of the brush noise pulse is used as a criterion for determining the rotational speed of the DC brush motor 2 and whether the film winding or rewinding is operating normally. The pulse interval of the noise pulse may be used as the cycle or pulse width of the brush noise pulse.

The present invention can also be applied to a camera in which all the films are wound up after a new film is loaded and the film is rewound by one frame each time a picture is taken.

Although the resistor 5 is used in this example for detecting brush noise of the DC brush motor 2, the diodes 3 to 3 and the transistors 4 to 4 for driving the DC brush motor 2 are at least integrated into an IC, Brush noise can also be detected by utilizing the pattern resistance of the IC and the voltage drop due to bonding.

[0022]

According to the present invention, since the photo interrupter and the like can be omitted, the structure can be downsized.

In the case of the photo interrupter, if dust or the like adheres to the detection portion, it malfunctions, but if electrically detected as in the present invention, there is no fear of that, and high reliability can be obtained.

Moreover, since the amplification factor of the amplifier and / or the set level of the comparison means are controlled according to the rotation speed of the DC brush motor, brush noise pulses are generated even if the rotation speed of the DC brush motor changes. It can be detected accurately and the film can be wound accurately.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of FIG.

FIG. 3 is a flowchart for explaining the operation of FIG.

FIG. 4 is a flowchart for explaining the operation of FIG.

5 is a flowchart for explaining the operation of FIG.

FIG. 6 is a flowchart for explaining the operation of FIG.

7 is a flowchart for explaining the operation of FIG.

8 is a flowchart for explaining the operation of FIG.

[Explanation of symbols]

 2 DC brush motor 6 Amplifier 7 Comparison means 8, 13 Winding control means 9 Battery 13 Control means

Claims (1)

[Claims] 1. A camera that winds a film every time a picture is taken, in which a DC brush that winds the film, an amplifier that amplifies brush noise generated by the rotation of the DC brush motor, and an output of the amplifier is above a set level A comparing means for generating an output, a winding control means for controlling the winding of the film by receiving the output of the comparing means, and an amplification factor of the amplifier and / or the comparing means according to the rotation speed of the DC brush motor. And a control means for controlling the setting level of the film winding device.