JPH0695189B2 - Program Shutter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a program shutter in which opening / closing operations of shutter blades are performed by a step motor.

(Prior Art) In a program shutter in which a shutter blade is opened and closed by a step motor, a drive pulse having a constant cycle is input to the step motor by a relays operation to rotate the motor forward to gradually open a sector for exposure. The phase of the drive pulse is switched at the time of step rotation corresponding to the amount, and the step motor is rotated in the reverse direction to close the sector and obtain a predetermined exposure.

In such a program shutter, since the step motor and the sector are connected via a plurality of gear mechanisms, the rotation phase of the step motor may vary due to the backlash of the gear mechanism and the tolerance of the parts themselves that make up the mechanism. Since a phase difference is likely to occur between the opening amount of the sector and the opening amount of the sector, and in particular, a large error is generated in the exposure with a small exposure amount, the shutter mechanism is provided with an adjusting member, and by adjusting this, the rotation of the step motor is rotated. A method is used to match the phase and the aperture of the sector.

However, since the exposure amount of the program shutter is automatically set internally according to the subject brightness, a standard subject of known brightness must be prepared in order to set a constant exposure level for adjustment. However, there was a problem that the adjustment work was troublesome.

(Purpose) In view of such a problem, the present invention provides a program shutter that allows a camera itself to perform an exposure operation corresponding to a constant brightness and thus easily test a shutter function without requiring special equipment. The purpose is to provide.

(Clarification of the Invention) That is, as a feature of the present invention, as shown in FIG. 1, a shutter mechanism main body in which a sector 1 forming a lens opening is opened and closed by a step motor 2 capable of forward and reverse rotation, and a subject brightness. An exposure data storage circuit means 4 for storing the number of steps driven corresponding to the subject brightness detected by the detection means 3 as data, and an exposure amount as an address, a pulse generation circuit means 5 for generating a motor driving reference clock pulse, The motor is normally rotated to open the sector, and the stepper motor 2 is rotated reversely to close the sector according to the data of the exposure data storage circuit means corresponding to the exposure amount determined by the subject brightness detection circuit means. Motor drive circuit means 7, mode selection means 8 for selecting and setting either test mode or shooting mode, and test It is composed of a control unit including a test item setting unit 9 for outputting an access signal to the data storage unit 4 when the test mode is selected, and an adjusting member for adjusting the shutter mechanism based on the data when the test mode is set.

(Structure) Therefore, details of the present invention will be described below based on illustrated embodiments.

FIG. 2 shows an example of a shutter mechanism to which the present invention is applied. In the figure, reference numeral 11 is a plywood plate to which a base plate 12 for positioning a lens is attached, and a sector chamber 13 is provided between the base plate 12 and the base plate 12.
Two sectors 14 are formed by means of a pin 15 and are pivotably provided here, which, in contrast, pivot and determine the lens aperture. Reference numeral 16 is a sector drive lever, which is rotatably supported by a shaft 17 implanted in the base plate 11, and has a groove portion formed at one end.
It engages with a pin 19a of a sector drive wheel 19, which will be described later, which is rotatably provided on the shaft 17 via 16a, and engages with the sectors 14 and 14 by a sector pin 20 implanted on the base plate side.
Numeral 19 is the sector drive vehicle described above, which is rotatably supported by a shaft 17 so as to be regulated to a reference position when stationary by the degree determining portions 19b, 19b formed on the outer periphery and a spring 18 which imparts left-handedness, and one end of which is provided. The formed tooth portion 19c is connected to a drive shaft 23a of a step motor 22 described later via a train wheel. In addition, reference numeral 21 in the figure indicates the degree determining units 19b, 1 of the sector drive vehicle 19.
The pin which engages with 9b and regulates the rotation range is shown.

FIG. 3 shows an embodiment of the step motor 22 described above. In the figure, reference numeral 23 is a four-pole rotor made of a permanent magnet, and one end of the rotor shaft 23a is projected so as to protrude from the upper plate 24 and the lower plate. Board 2
The sector drive wheel 29 of the shutter mechanism is configured to be rotatably attached to the shaft 5 and to be driven by the pinion 26 attached to the shaft 23a. 27 and 28 are stators made of a U-shaped magnetic material each having two legs formed by winding exciting coils L ₁ and L ₂ around _one leg, and the rotor 23 is attached to the tip of each stator. The magnetic poles 27a, 27b, 28 are placed at a position of 90 ° with respect to
It is formed by forming a and 28b. These stators 27,
28 is positioned by guide pins 29, 29, ... In such a manner that each one of the magnetic pole portions 27b, 28b is positioned at 45 ° with respect to the rotor 23, and is arranged in a "H" shape. Is configured so that the rotor 23 can rotate in the forward and reverse directions.

FIG. 4 shows an embodiment of a signal processing device which is an essential part of the present invention. In the figure, reference numeral 40 is a microcomputer which is a central part of the signal processing device and is linked to a release button (not shown). When the operating voltage V _DD is supplied from the power source 42 by the power switch 41, the transistor 43 power-holds to start a series of operations based on the program, and when a predetermined time has elapsed after the release switch 44 was turned on. It stops the operation by cutting off the supply of operating voltage.The input port has a brightness detection circuit 45 that outputs a signal suitable for the apex calculation according to the brightness of the subject, and a semi-selection mode between shooting mode and test mode. Fixed switch 46,
And switch 47 for setting the test items in the test mode
a and 47b are connected. These switches 46, 47a, 47b
Various modes shown in Table 1 can be selected depending on the ON-OFF state of.

A step motor 2 for driving the sector 1 is connected to the output ports φ _{0 to} φ ₂ of the microcomputer 40 via a step motor drive circuit 48. In the figure, reference numerals A _{0 to} A ₂ are indicator lights for issuing various warnings, and 49 is
3A and 3B respectively show a crystal oscillator for generating a reference timing signal of the processing device.

FIG. 5 is a block diagram showing an embodiment of a motor drive signal generation unit. In the figure, reference numeral 51 is a data ROM, and in the photographing mode, the photographing data input from the brightness detection circuit via the data bus 52 Data bus in test mode
Access is made by the test item data input via 52, and the motor control data and the strobe photographing timing data are stored in blocks I to III divided into three parts.

That is, the block I stores the step motor rotation amount corresponding to the exposure time in consideration of the time shift from the drive pulse caused by the response delay of the mechanical system, and the repetition frequency proportional to the exposure amount, that is, the exposure amount. When the time is long, a pulse having a long cycle is selected, and when the exposure time is short, the data P for selecting a pulse having a short cycle, the step number data Ns for performing step rotation by the selected pulse, and the direction change time The exposure amount E is taken as an address and stored as a set with the interpolation amount data Td representing the width of the drive pulse of the drive pulse, and is accessed by the exposure amount Ex obtained by the EE calculation, and the rotation amount of the step motor corresponding to the exposure amount is set. Is configured to be obtainable.

If the block II does not have a mechanism to stop the sector with the F value obtained from the EE calculation like the program shutter, the strobe is triggered when the sector opens up to the F value obtained from the calculation and the hillside emission is performed. The time information for storing the time information is stored, and the timing Tf when the specified aperture value F is reached in the process of opening the sector is used as data, and the calculated value Afm is a constant value C that takes into account the time lag caused by the response delay of the mechanical system. _The value Afm + C ₀ to which ₀ is added is stored as an address, and the value is accessed by the calculated value AFM to output the timing at which the aperture reaches a predetermined aperture value F.

Block III uses a time point between the reverse rotation signal and the reverse rotation of the sector as a reference, based on the generation time of the signal for rotating the step motor reversely, and sets a constant value C ₁ corresponding to this deviation to E _0.
The value E ₁ added to is taken as an address, the timing Tf for forming the maximum opening is stored as data, and time information is output to perform peak light emission.

Returning to FIG. 5 again, 53 is a pulse generation circuit for data RO
It is configured to generate a pulse corresponding to the repetition frequency data P read from M51. A counter 54 is preset with the step driving number Ns before the sector opening and is down-counted by the pulse from the pulse generation circuit 53, and when it becomes zero, the interpolation amount data Td is preset and down-counted by the reference clock. The step drive number Ns is preset again when it becomes zero. Reference numeral 55 is a shift register, which converts the pulse from the counter 54 into a two-phase pulse φ ₁ and φ ₂ with a phase difference of 180 degrees, and when the interpolation amount preset in the counter 54 becomes zero. It is configured to invert the phase of the output pulse. In the figure, reference numeral 56 is an address conversion circuit for converting an address corresponding to the test item data input via the data bus 52, and 57 is a latch circuit for outputting a φ ₀ phase in response to a signal from the data bus 52. Shown respectively.

FIG. 7 shows an embodiment of a step motor drive circuit, which is an alternate switching circuit having gates G _{1 to} G ₄ and G _{5 to} G _{8 on} drive coils L ₁ and L ₂ of the step motor, respectively. The transistors Tr ₁ to Tr ₄ and Tr _{5 to} Tr ₈ are connected to each other via the, and the step motor is configured to be driven in the forward and reverse directions according to the signals φ _{2 to} φ ₀ from the shift register 55 and the latch circuit 57. ing.

Next, the operation of the apparatus configured as described above will be described based on the flowchart shown in FIG.

When the release button is pushed to the first position, the power switch 41 interlocking with this is turned on, the operating voltage V _DD is supplied from the power source 42 to the signal processing device 40, and at the same time, a signal is sent to the reset terminal R after a certain period of time. When applied, the reset of the device is released, and the operating voltage V _DD is supplied to the device regardless of ON-OFF of the power switch.

At this point, if you turn off the shooting-test selection switch,
The test item setting switches 47a, 4 are set in the test mode regardless of the data from the subject brightness detection circuit 45.
Data ROM according to the test item data selected by 7b
Is to be accessed. For example, if the test item switches 47a and 47b are turned off, the data R
The address of the block I of the OM51 is accessed and the exposure amount Ev18 is selected regardless of the subject brightness.

In such a state, the shutter main body is set in the shutter test apparatus, the release button is pushed to the second position, and the release switch 44 is turned on. As a result, the shutter enters the normal exposure process.

That is, the pulse of the repetition period P corresponding to Ev18 from the data ROM 51 and the step driving number data Ns are preset in the counter. Then, the signal φ ₀ of the step motor is set to high level to excite the step motor (FIG. 9).
This state is maintained for 10 ms and the subsequent processing for stable operation of the step motor is performed. When the rotor stands still, a forward rotation pulse having the selected pulse width P is input to the counter and shift register 55, and the motor drive circuit
A drive pulse is supplied to the step motor via 48 to rotate the motor in the forward direction step by step to start opening the sectors 14 and 14 from the reference position, and at the same time, the counter is decremented by one. In this way, when the preset number of step drive pulses are output to the counter 54, the direction is changed from the address of the data ROM 51 accessed before the operation while the step motor is rotating toward the final step. The width of the driving pulse at that time, that is, the interpolation amount data Td is output and preset in the counter 54, and at the same time, the clock is down-counted. When the down count of the counter 54 progresses and the count is completed, a count completion signal is generated. With this signal, the number of steps Ns is transferred from the data ROM to the counter.
At the same time, the shift register switches the shift direction to shift the contents by 1 bit and outputs a pulse having the same width P as the interpolation pulse immediately before the reverse rotation to the drive circuit to force the motor. Reverse to. Due to the reverse rotation of the pulse motor, the sectors 14 and 14 gradually start to close, rotate stepwise every time a drive pulse is input, and stop the step drive pulse when the counter 54 reaches zero. As a result, the sectors 14 and 14 are returned to their original positions and the optical path is closed, and at the same time, the step motor signal φ ₀ is output for a certain period of time, for example, 10 milliseconds to forcibly stop the motor and the sector.

When the exposure operation was completed, the exposure amount displayed on the test device was read, and the shutter mechanism performed the predetermined exposure,
If there is an error, the adjustment member of the shutter mechanism body is adjusted to make a correction.

Also, when testing the timing of strobe emission,
For example, when the test item setting switch 47a is set to OFF and 47b is set to ON, the block III of the data ROM 51 is accessed and the required data is preset in the counter 54.

When the release switch 44 is turned on in such a state, the sector opens and closes corresponding to the set exposure amount data, and at the same time, the strobe trigger is generated at the set timing. When the exposure is completed, the exposure amount and the trigger timing displayed on the test apparatus are checked, and if there is an error, a predetermined adjustment is performed.

Hereinafter, by changing the test item setting switch in this manner, various opening patterns as shown in FIG. 10 are reproduced, and the required inspection can be performed.

On the other hand, in the case of shooting, if the shooting-test selection switch 46 is turned off, the data ROM 51 becomes accessible by the data from the subject brightness measuring circuit 45. In such a state, if the release switch is pushed to the first position, the subject brightness detection circuit 45
Activates and starts metering. When the photometric process is completed, Ex
= L + S + A (where L is the photometric value code, S is the film sensitivity code, and A is the difference between the open F values) to obtain the exposure amount.

The operation up to this point is automatically and continuously performed after the power switch is turned on.

When the release button is pushed to the second position, it is judged whether the release switch 44 is ON or not, and the release switch S ₂
Is ON, the address E of the block I of the data ROM 51 is accessed based on the exposure amount calculated in the previous step, and at the same time, the step motor is driven based on this data to perform exposure according to the exposure amount. To do.

(Effect) As described above, according to the present invention, it is possible to externally operate the exposure data storage circuit means that stores the number of steps driven corresponding to the exposure amount as data and the exposure amount as an address. Since it can be accessed by the setting means, the exposure level can be extremely easily and accurately created using the data of the exposure data storage means regardless of the photometric data, and the shutter mechanism can be used without requiring special equipment. Can be adjusted accurately.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus for clearly showing the configuration of the present invention,
2 (a) and (b) are plan views showing an embodiment of a shutter mechanism to which the present invention is applied, and cross-sectional views of FIG. 3 (a) and (b) are steps used in the same apparatus. FIG. 4 is a plan view and a sectional view of an apparatus showing an embodiment of a motor, FIG. 4 is a schematic view of the apparatus showing an embodiment of the present invention, and FIG. FIG. 6 is a block diagram of a device showing an embodiment, FIG. 6 is a memory block diagram of a data ROM in the same control unit, FIG. 7 is a block diagram of a circuit showing an embodiment of a step motor drive circuit, and FIG.
FIG. 9 is a flowchart for explaining the operation of the above apparatus,
FIG. 10 is a waveform diagram showing the operation of the above apparatus, and FIG. 10 is an explanatory diagram showing an example of an exposure pattern in the test mode. 1 …… Sector, 2 …… Step motor 40 …… Microcomputer 41 …… Power switch 42 …… Release switch 45 …… Brightness detection circuit 46 …… Shooting-test selection switch 47 …… Test item setting switch 48 …… Step Motor drive circuit

Claims (1)

[Claims] 1. A shutter mechanism comprising a sector forming a lens opening, and a step motor capable of rotating forward and backward for opening and closing the sector, a subject brightness detecting means for detecting a subject brightness, and an exposure amount. Exposure data storage means for storing the exposure amount as an address with the step drive number as data, pulse generation circuit means for generating a motor driving reference clock pulse, the motor to rotate the motor forward to open the sector, and the subject brightness Motor drive circuit means for reversing the motor to close the sector according to the data of the exposure data storage means corresponding to the exposure amount determined by the detection means, and mode selection for selectively setting either test mode or photographing mode Means and a test term for outputting an access signal to the exposure data storage means when the test mode is selected A control unit provided with a setting unit, a program shutter consisting of an adjustment means for adjusting the shutter mechanism on the basis of the test item data output in response to the test item setting means.