JP2963013B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera for detecting a movement of a film by using a position detecting means.

[0002]

2. Description of the Related Art Conventionally, a film movement detection system in a camera includes a mechanical detection method and an electrical detection method. The mechanical method has recently changed to an electrical detection method because it requires more mechanical space than the electrical method.

In recent years, as the specifications of cameras have become more sophisticated, the load on the power supply has also increased, and the chances of using a low voltage have increased. However, an inexpensive power source that can be used easily and inexpensively in many countries around the world is typically a AA manganese dry battery or the like, but its load characteristics are still lower than those of recently developed batteries.

Therefore, it is difficult to detect the movement of the film with such a battery, and in the case of low-temperature operation, the output voltage is lowered because the internal resistance of the battery is particularly high. As a result, the movement of the film cannot be detected because the operating range of the light emitting portion of the element is below the operating range.

Further, it is general to judge that the film is at the end when no signal is generated by utilizing the fact that the film does not move at the end of the film. If the movement cannot be detected, the end is determined and the film is rewound.

FIG. 2 is a circuit example of a general electric fill detection system of a conventional camera.

Reference numeral 2-1 denotes a control element for performing overall control of the camera. 2-2 is an oscillation circuit for oscillating the oscillator 2-11 stably. 2-3 is a microprocessing unit for performing arithmetic processing in the control element 2-1. 2
Reference numeral -4 denotes a signal processing circuit, in particular, a circuit for processing a film movement detection signal in this case. 2-
A circuit 5 drives a liquid crystal display element, which is a 2-12 LCD, which transmits various information of the camera by a display circuit. 2-6 is
ROM for storing 2-3 software information. 2-7 is a RAM for storing 2-3 temporary information. 2-8 is a circuit for processing a SW input for performing each operation of the camera. 2-9
Is a drive circuit for operating each drive unit of the camera. 2-10 is a circuit for controlling each information of the camera and sends the result to 2-3. 2-11 is a vibrator connected to 2-2. 2-12 is an LCD display element connected to 2-5. 2-13 is a load circuit connected to 2-10 and a power supply. 2-14 is an optical measurement circuit connected to 2-10. 2
-15 is a distance measurement circuit connected to 2-10. 2-1
6 is a motor drive circuit for driving the film. 2-17 is a motor for driving the film.
Reference numeral 2-18 denotes a switch for selecting each operation of the camera, which is connected to 2-8. 2-19 is a diode for stabilizing the power supply of the control element. 2-20 is a capacitor for stabilizing the power supply of the control element. 2-21 is a camera power supply. 2-22 is a film movement detecting element. 2-22-1 is a light receiving section in 2-22. 2-22-2 is 2-2
Light emitting part in 2. 2-23 is a resistor that converts the current of 2-22-1 into a voltage. Reference numeral 2-24 denotes a resistor for limiting the current of 2-22-2.

[0008]

Generally, an electric film movement detecting means of a camera uses holes (perforations) formed at regular intervals on both sides of a film, and a difference in light reflectance between the hole and the film surface is used. From the method of detecting using a light sensor, etc., which is the detection means, and the fact that the movement of the film is mechanically converted into the movement of a rotating body, etc., and that this rotation rotates and the light transmittance changes There is a way to detect it. In any of the above methods, since light is used, a light emitting diode or the like is used to generate light. However, since this light emitting diode has an operating voltage of about 1.4 V, it is a general battery of AA manganese dry battery 2.
In this book, the new battery voltage is 3 V, but in a low temperature state, it is 2.5 V.
When the current required for driving the motor is 1 A or the like because the internal resistance is about 2.7 V and the internal resistance is about 1 Ω, the light emitting diode and the circuit for driving the light emitting diode are 1.5 to 1.
7V is supplied, and a voltage higher than the required voltage of 1.7 V cannot be supplied. Therefore, electrical movement of the film cannot be detected in a low voltage state. An object of the present invention is to provide a camera capable of detecting the movement of a film even in a low voltage state.

[0009]

To achieve the above object, the present invention provides a power supply voltage detecting means for detecting a power supply voltage, a film driving means for moving a film,
In a camera having a position detecting means for detecting the movement of a film and a current control means for controlling a current flowing to the position detecting means, when a power supply voltage detected by the power supply voltage detecting means is equal to or lower than a predetermined voltage. The current flowing through the position detection means is pulse-driven by the current control means.

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

FIG. 1 shows an embodiment of the present invention. This is described below. Reference numeral 1-1 denotes a control element for performing overall control of the camera. Reference numeral 1-2 denotes an oscillation circuit which stably oscillates an oscillator 2-11 to generate a basic operation time of the entire circuit. 1-3 is a microprocessing unit for performing arithmetic processing in the 2-1 control element, and 1-4 is a signal processing circuit in the present embodiment, particularly a circuit for a film movement detection signal in this embodiment. Reference numeral 1-5 denotes a display circuit which transmits various information of the camera and drives a 2-12 liquid crystal display element. 1
Reference numeral -6 denotes a ROM for storing software information, which stores camera sequences and the like. 1-7 is R for storing temporary information
AM. Reference numeral 1-8 denotes a circuit for processing SW input for performing each operation of the camera. 1-9 is a drive circuit for operating each drive unit of the camera. 1-10 is a circuit for controlling each information of the camera and sends the result to 1-3. 1-11 is a vibrator. 1-12 is an LCD display element connected to 2-5. 1
-13 is a load circuit connected to the power supply 2-10. 1-1
4 is an optical measurement circuit connected to 2-10. 1-15 is a distance measurement circuit connected to 2-10. 1-16 is a motor drive circuit for driving the film. 1-17 is a motor for driving the film. Reference numeral 1-18 denotes a switch for selecting each operation of the camera, which is connected to 2-8.

Reference numeral 1-19 denotes a diode for stabilizing the power supply of the control element. 1-20 is a capacitor for stabilizing the power supply of the control element. 1-21 is a camera power supply.
1-22 is a film movement detecting element. 1-22-1 is a light receiving section in 2-22. 1-24 is a resistor for limiting the current of 2-22-2. Reference numeral 1-25 denotes a storage element for temporarily storing electric charges to supply a current to the position detection element. Reference numeral 1-26 denotes a separation element for preventing power fluctuation from being transmitted to the position detection element. An A / D conversion circuit 1-30 converts analog data such as AE, AF, and power supply voltage into a digital signal and sends the digital signal to 1-3.

The camera sequence starts its operation based on information from each SW 1-18.

In this embodiment, a description will be given of the detection of film movement such as winding.

It is generally known that various limiting operations are performed depending on the power state of a camera in order to start a camera sequence. For example, a warning display for replacing a battery with a low power supply voltage is an example thereof. Here, the film movement detection when the power supply voltage is low will be described. With the circuit configuration shown in FIG. 2, when a high load is connected or the like, the Vf of the light emitting diode 2-22-2, ie, the forward operating voltage, the resistance 2-2-24, and the signal processing circuit 2-2-4 are used. If the voltage is lower than the required voltage, it will not operate. Therefore, in the present embodiment, a power supply voltage is prevented from lowering by a diode 1-26 in order to avoid a voltage fluctuation, and a power supply voltage before high-load connection is maintained by a capacitor 1-25.

In the conventional example, when the power supply voltage becomes equal to or lower than a predetermined voltage as shown in FIG. 3, that is, equal to or lower than the voltage applied to the signal processing circuit, the light emitting element 2-22-2 stops operating as shown in FIG. Film movement cannot be detected by light. Also in this embodiment, in order to operate the element 1-22 with the electric charge of the storage element 1-25, it is necessary to increase the charge amount, which is not practical. Normally a few meters for a 1-22-2 diode
A to run A and move one film at a time.
Assuming that the operation voltage is 1.7 V as described above and the voltage is 2.7 V, the difference is 1.0 V, and the capacitance of this capacitor is 2 to 3000 μF, which requires a huge capacitance. Therefore, as shown in FIG. 5, pulse driving is performed to limit the current flowing through the diode within a necessary range. This pulse drive is 10 mS to 50 mS in a system utilizing light reflection at a hole portion which is a perforation of the film, so it is necessary to set a pulse of 10 mS or less. Since such an operation naturally depends on the state of the power supply voltage, it is necessary to confirm the state of the power supply voltage immediately before the start of the camera sequence. Therefore, it is necessary to connect the load circuit 1-13 to check the internal resistance of the power supply. Further, even during operation such as motor driving, when the power supply reaches a predetermined voltage, the above pulse driving must be performed.

Also, by having a plurality of predetermined voltages, the ON time / OFF time of the pulse can be changed according to the fluctuation of the power supply voltage. When the predetermined voltage is high, the movement can be detected finely, and the movement can be low. In the case of the voltage, the OFF time is lengthened and the detection is performed to the last minute.

Further, by using a current variable circuit as shown in FIG. 6 and the like as long as the current flowing through the diode can be detected, it is possible to detect at a lower voltage for a longer time. This current limiting limit does not affect the actual photographing if it is determined at the time of initial winding when the film is loaded. Further, it is needless to say that the determined value is within the time in consideration of the discharge characteristics because of the effect of discharging the power supply.

It is also a very effective means to prevent the current from flowing in the initial stage of film driving, in which the film is not moved in order to effectively use the electric charge of the capacitor.

Further, in order to accumulate electric charges in the electric charge storage capacitor during driving of the film, the driving of the film is temporarily stopped to increase the power supply voltage. At this time, the movement of the film does not stop, but in order to detect the movement of the film, usually one side of the edge of the hole which is a perforation is detected, and a certain time is required until the next side of the perforation is detected. It is thought that there is room. Therefore, the charge of the capacitor is charged by this time difference. According to the above-described method, charges can be effectively used without waste, and film detection can be performed even at a low voltage.

[0030]

As described above, the present invention provides a power supply voltage detecting means for detecting a power supply voltage, a film driving means for moving a film, a position detecting means for detecting a movement of a film, In a camera having a current control means for controlling a current flowing to the detection means, when a power supply voltage detected by the power supply voltage detection means is equal to or lower than a predetermined voltage, the current flowing to the position detection means is controlled by the current control means. , The movement of the film can be detected even in a low voltage state.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of the present embodiment.

FIG. 2 is a conventional schematic circuit diagram.

FIG. 3 is a diagram illustrating power supply voltage fluctuation during driving of a motor.

FIG. 4 is an operation diagram when a light detection method using a conventional circuit is used.

FIG. 5 is an operation diagram of a light detection type light emitting unit when pulse driving is performed according to the present embodiment.

FIG. 6 is a partial circuit diagram in the present embodiment.

[Explanation of symbols]

1-1 Control elements for overall control of camera 1-2 Oscillator circuit 1-3 Microprocessing unit 1-4 Signal processing circuit 1-4-4 Transistor for controlling current of light emitting element 1-4-5 Current Resistor for detection 1-16 Motor drive circuit for driving film 1-17 Motor for driving film 1-19 Diode for stabilizing power supply of control element 1-20 Stabilizing power supply of control element Condenser 1-21 Camera power supply 1-22 Film movement detecting element 1-22-1 Light receiving section 1-22-2 Light emitting section 1-23 Resistance 1-24 Resistance 1-25 Supply current to position detection element Element that temporarily accumulates electric charge for the purpose of the isolation 1-26 Separation element for preventing power supply fluctuation from being transmitted to the position detection element

Claims (6)

(57) [Claims] 1. A power supply voltage detecting means for detecting a power supply voltage, a film driving means for moving a film,
In a camera having a position detecting means for detecting the movement of a film and a current control means for controlling a current flowing to the position detecting means, when a power supply voltage detected by the power supply voltage detecting means is equal to or lower than a predetermined voltage. A camera, wherein a current flowing through the position detection means is pulse-driven by the current control means. 2. The camera according to claim 1, wherein said current control means changes a drive interval of pulse driving according to a power supply voltage detected by said power supply voltage detection means. 3. The camera according to claim 1, wherein said current control means changes a current flowing through said position detection means according to a power supply voltage detected by said power supply voltage detection means. 4. The camera according to claim 1, wherein a period during which no electric current is supplied to said position detecting means is provided at a predetermined initial time of film driving. 5. A storage device for storing a charge for supplying a current to the position detecting means, wherein film driving is not performed for a certain period of time to store the charge in the storage device. The described camera. 6. A storage element for storing an electric charge for supplying a current to the position detecting means, wherein the electric charge is stored in the storage element until one side of the perforation is detected until one side of the next perforation is detected. The camera according to claim 1, wherein: