JP3306213B2 - Adjusting the strobe charging voltage of the camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is, strobe charging voltage adjustment side of the camera method, and more particularly relates to adjust how by the charging voltage detection system of the flash of the camera.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting a charging voltage of a main capacitor of a strobe in a camera, a voltage detecting element such as a zener diode TD51 is used as shown in a circuit diagram of FIG. A method of detecting the charging voltage of the main capacitor C52 for 53 has been applied. However, according to this method, there is a problem that the detected voltage is one point and the detected voltage has large variations. As a method of improving this, the present applicant has proposed a method of detecting and adjusting the charging voltage of the main capacitor of a strobe in a camera with a built-in strobe proposed in Japanese Patent Application No. 5-8477. FIG. 4 shows a circuit diagram of a strobe device using this detection and adjustment method.

In this strobe device, as shown in the circuit diagram of FIG. 4, the voltage of a main capacitor C63 for an Xe tube 64, which is a flash tube, is divided by voltage dividing resistors R61 and R62, and C
The voltage is input to the UP 60 as a divided resistance voltage VST which is a detection voltage. An analog-to-digital conversion (hereinafter referred to as an A / D conversion) is performed using the A / D circuit inside the CPU 60.
And write it to memory. When the actual charging voltage is detected, the main capacitor charging voltage is detected by comparing the memory storage value with the divided resistance voltage, and control such as stopping the charging operation and permitting the release of the camera is performed.

In practice, there are variations in the resistance values of the voltage dividing resistors R61 and R62, A / D errors, and the like, and these become detection errors of the main capacitor voltage. Therefore, for each camera, a voltage, for example, 330 V, at which charging is actually stopped is applied to the anode line of the diode D65. The voltage VST at that time is converted into digital data by an EEP (not shown).
Write to ROM. Using this data, control such as charging operation stop and camera release permission is performed to absorb the detection error and enable accurate main capacitor voltage detection.

Here, the error of the detection voltage of the main capacitor C63 will be described in detail below. FIG. 5 is a circuit diagram showing the concept of the main capacitor voltage detecting section.

As shown in FIG. 1, the main capacitor voltage V
The voltage VST obtained by dividing MC by R76 and R77 is the comparator CP.
78 is input to an inverting input terminal, and a non-inverting input terminal is input to VDAC as a reference voltage. This reference voltage VDAC
Can be made variable by DAC data which is digital data.

Since the voltage VST is VST = (R77 / (R76 + R77)). Times.VMC, in order to detect that the target main capacitor voltage VMC1 has been reached, the reference voltage VDAC is set to the next voltage VDAC1. You should keep it. That is, VDAC1 = (R77 / (R76 + R77)). Times.VMC1. The voltage VDAC1 becomes equal to the voltage dividing resistance voltage VST1 which is a detection voltage.

If there is no variation in the main capacitor voltage detecting section, a DA corresponding to the calculated voltage VST is obtained.
What is necessary is just to store the C data as a fixed value in the memory.
However, in practice, an error occurs in the voltage detection of the main capacitor due to variations in the voltage detection unit and A / D errors. For example, when a resistor of R76 = 20 MΩ ± 2% and R77 = 47 KΩ ± 1% is used, the variation Δ of the MC due to the resistance value is Δ
VMCR is the target value of the main capacitor VMC = 33
At 0V, ΔVMCR = ((330V / ((20M + 47K) / 47K))) × (20M × 1.02 + 47K × 0.99) / (47K × 0.99)) − 330V = 10V.

Similarly, although there is a difference depending on the circuit form in the error caused by the A / D conversion unit, for example, the A / D
Variation ΔVMC as variation of VMC due to quantization error
A is about 0.72 V, the change ΔVMCO due to the offset of the comparator is about 4.26 V, and the change ΔVMCD due to the variation of the reference voltage VDAC is about 6.39.
V, and the change Δ due to the input bias current of the VST terminal
VMCB is about 6.6V. Accordingly, the total variation ΔVMC of VMC when the main capacitor VMC = 330V as the target value is represented by the sum of the above changes, and ΔVMC = ΔVMCR + ΔVMCA + ΔVMC0 + ΔVMCD + ΔVMCB = 10V + 0.72V + 4.26V + 6.39V + 6.6V = 27.97V . That is, in this case, the detected voltage of the main capacitor VMC varies within a range of 330 V ± 27.97 V with respect to the target voltage of 330 V.

In order to absorb these errors, a pseudo voltage corresponding to a target charging voltage of 330 V is applied to the VMC line during camera assembly as described in the section of the prior art, and the data is stored in the EEPROM. And used for actual shooting.

[0011]

The circuit of the strobe device shown in FIG. 4 in a camera with a built-in strobe proposed in Japanese Patent Application No. 5-8477 is applied, and a voltage of 330 V is applied to the VMC line during the assembling process. To apply the error and write the absorption adjustment data into the EEPROM, the voltage 30
A high voltage of about 0 V needs to be applied using a check pin or the like during camera assembly. However, when each member is crowded, there is a possibility that the check pin may erroneously touch a surrounding metal object, a control circuit board of the camera, or the like, thereby destroying the control circuit or the like.

In the case of a conventional camera with a built-in strobe as shown in a perspective view of FIG.
Strobe circuit board 74, control circuit board 75, connection board 7
9. It is very difficult for the light emitting portion 73 and the like to be in the way, and for the check pin to be brought into contact with the voltage application point on the strobe circuit board 74. Therefore, it is necessary to dispose the substrate 75 and the light emitting section 73 apart from the strobe circuit board 74. In addition, it is necessary to similarly separate the camera mechanism members from the strobe circuit board 74. Such an arrangement limits the internal layout of the camera, and has been a problem especially in recent small cameras.

The present invention, the problem which has been made to solve the, in the step of adjusting the-in flash charging voltage, the camera limited to the camera internal layout is small prevents the destruction of the camera by the high voltage applied by check pin The present invention provides a method for adjusting the charging voltage of a strobe.

[0014] Strobe charging voltage of the first camera of the present invention
Adjustment method is the strobe circuit board including the main capacitor
And the strobe circuit board and the main
A / D conversion of the charge voltage of the storage capacitor
A camera control circuit board including detection means.
Camera's strobe charging voltage adjustment method
The control circuit board is electrically connected to the strobe circuit board.
Of the camera control circuit board
The main capacitor is connected to the input terminal of the voltage detecting means.
Applying a pseudo voltage corresponding to the charge adjustment voltage of
The voltage detection of the voltage detection means itself is performed based on the pseudo voltage.
Process to adjust the output variation and the main controller
The above-mentioned strike where the charge adjustment voltage of the capacitor is not adjusted
The robo circuit board is electrically connected to the camera control circuit board.
And a subsequent step.

[0015] Strobe charging voltage of the second camera of the present invention
Adjustment method is the strobe circuit board including the main capacitor
And the strobe circuit board and the main
A / D conversion of the charge voltage of the storage capacitor
Camera control circuit board including detection means and EEPROM
And strobe charging voltage adjustment method
And the camera control circuit board is provided with the strobe circuit base.
When it is in a single state before it is electrically connected to the board,
Connect the input terminal of the voltage detection means on the camera control circuit board to
A pseudo voltage equivalent to the charge adjustment voltage of the main capacitor
And detecting the voltage based on the pseudo voltage.
Data for correcting the voltage detection variation of the output means itself
Is stored in the EEPROM, and
The charge adjustment voltage of the main capacitor has not been adjusted.
The strobe circuit board and the camera control circuit board
Electrically connecting).

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a main block configuration diagram of a control circuit for a camera with a built-in strobe, showing a first embodiment of the present invention. The control circuit for the camera of the present embodiment, as shown in FIG.
A strobe circuit board 32A on which a strobe circuit 32B as a strobe unit set 32 is mounted, and a camera control circuit 31B including a control unit for the strobe circuit 32B as a camera control unit set 31 as a shooting sequence control unit set are mounted. And a camera control circuit board 31A.

The strobe circuit 31B mainly divides the voltage of the oscillation boosting circuit 13 and the voltage of the main capacitor C5, and divides the voltage of the resistors C6 and R7 connected in parallel with the capacitor C5.
And the main capacitor C
5, a trigger circuit 15, and a Xe tube 16 as a flash tube.
Etc.

The camera control circuit 31B mainly controls each control element.
And a control circuit 20 including a CPU and the like, which incorporates voltage detecting means for the target charging voltage VMC of the main capacitor C5 based on the A / D conversion value of the divided resistance voltage VST of the output. , The voltage dividing resistance voltage VST is
The A / D circuit 28, which performs the A / D conversion and detects the charge voltage VMC, detects the charge state of the main capacitor C5 in addition to the data for controlling each camera. An EEPROM 29 storing charge voltage determination data as strobe information for stopping the operation of the flash drive, data of a release lock voltage corresponding to the voltage of the main capacitor C5, a mode setting circuit 30 for a photographing mode, and a shutter drive. It comprises a circuit 25, a photometric circuit 21, a distance measuring circuit 22, a lens driving circuit 23 for driving a photographing lens, a winding circuit 24 for winding driving, and the like. In addition, the strobe charging voltage detection system
It comprises the above charging voltage detecting means and an EEPROM 29.

In the camera of the present embodiment constructed as described above, when the strobe circuit board 32A and the camera control circuit board 31A are separate from each other before assembly, a charging voltage detection system for the strobe is used. Make adjustments. Although this adjustment method will be specifically described later, a voltage dividing resistance voltage based on a pseudo voltage corresponding to a target main capacitor charging voltage VMC is given to the camera control circuit board 31A alone, and the A / A The EEPR is used as charge state determination data Dc as strobe information for recognizing that the D-converted value has reached the main capacitor charging voltage VMC.
Write to OM29. If there is already the charging voltage detection determination information based on the written reference design value,
If the values are different, rewrite.

The adjustment of the charging voltage detection system is completed by the above-described adjustment processing. Thereafter, the strobe circuit board 32A and the camera control circuit board 31A are integrated into a camera. At the time of flash photography by the camera, the above EEP
Based on the charging voltage determination data Dc in the ROM 29, the stop of the oscillation boosting circuit 13 and the release lock when the main capacitor C5 is charged are executed.

The method of adjusting the main capacitor charging voltage detection system before assembling the camera will be described in detail. First, the check point PA of the A / D circuit 28 for the camera control circuit board 31A alone (FIG. 1) ) Is applied. The voltage dividing resistance voltage VST at this time is a voltage dividing resistance voltage for a pseudo voltage equivalent to the target charging voltage VMC for the main capacitor C5 equivalent to the target flash circuit 32B, and the voltage dividing resistances R6 and R7 are called. The value is given as the divided voltage or the divided voltage when the divided resistors R6 and R7 have been measured.

A when the above-mentioned voltage dividing resistance voltage VST is applied
The digital conversion value of the / D circuit 28 is used as the control circuit 20
And the value is written into the EEPROM 29 as the charge state determination data Dc. The camera control circuit board 31A mounted with the EEPROM 29 in which the charge state determination data Dc is written is integrated with the strobe circuit board 32A and incorporated in the camera.

As described above, according to the camera of this embodiment, when the charge state determination data Dc is written into the EEPROM 29, the strobe charge voltage is set to VMC in the assembled state as in the above-described conventional camera. The operation of writing a data in the EEPROM by applying a high voltage, for example, 330 V, to the line through a test pin is eliminated, and the danger of destroying the control circuit is eliminated. Furthermore,
Since there is no work of applying the high voltage, the arrangement position of each component is less restricted, and free arrangement is possible.

In this embodiment, the variation in the resistance value of the voltage dividing resistors R6 and R7 of the actual flash circuit 32B cannot be absorbed, but the variation in the A / D circuit 28 can be absorbed. That is, only the variation ΔVMCR due to the variation of the resistance value VMC and the variation ΔVMCA due to the variation of the reference voltage VDAC described in the section of the prior art described above, and the main capacitor voltage VMC is 330 V ± 10 including the detection variation. .72V.

The magnitude of the variation of the main capacitor voltage VMC is a value which can be sufficiently tolerated in consideration of the detection variation of about ± 15 to 20 V in the conventional voltage detection method using a Zener diode or the like. If you want to reduce the variation even more, use the strobe circuit 32
This can be coped with by reducing the tolerance of the voltage dividing resistors R6 and R7 of B.

As another method, the resistance values of the voltage dividing resistors R6 and R7 of each of the strobe circuits 32B or the voltage values divided by the voltage dividing resistors R6 and R7 are stored in the strobe circuit board 32A.
Each time, make a label that is easy to read with numbers or barcodes, and attach it. Then, by reading this value at the time of assembling the camera and correcting the value of the EEPROM 30, the charging voltage V of the main capacitor C5 can be obtained.
The variation in the detection of MC can be further reduced.

Next, a camera according to a second embodiment of the present invention will be described. FIG. 2 is a main block configuration diagram of a control circuit of the camera with a built-in strobe of the present embodiment. Similarly to the camera of the first embodiment, the control circuit of the camera of the present embodiment also has a strobe circuit board 34A on which a strobe circuit 34B as a strobe section set 34 is mounted, and a camera control section which is a shooting sequence control section set. A camera control circuit board 33 </ b> A on which a camera control circuit 33 </ b> B including a control unit of the above-described strobe circuit as the set 33 is mounted.

The camera of this embodiment is different from that of the first embodiment in that voltage dividing resistors R36 and R37 are provided on the camera control circuit board 33A side. It is the same as that of the first embodiment. Therefore, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the case of this embodiment, the method of adjusting the charging voltage detection system in the camera according to the present embodiment is as follows: the camera control circuit 33B having the built-in main capacitor charging voltage detecting means includes a voltage dividing resistor R36, Since the R37 is provided, the checkpoint part PB on the control circuit 33B is provided.
A pseudo voltage corresponding to the target main capacitor charging voltage VMC is applied to the target. By the application of the pseudo voltage, the voltage dividing resistor voltage VST is changed through the voltage dividing resistors R36 and R37 to the A / D circuit 2.
8 and A / D converted.

The subsequent processing is the same as that of the first embodiment, and the main capacitor C5, which is flash information based on the A / D converted value, is transmitted via the control circuit 20.
Is written into the EEPROM 29, and the adjustment of the charging voltage detection system ends.

As described above, in the case of the camera of this embodiment, there is no danger of breaking the control circuit when writing the charge state determination data Dc into the EEPROM 29 as in the case of the first embodiment. There are fewer restrictions on the location of each component. In the camera of this embodiment, since the voltage dividing resistors R36 and R37 are provided on the camera control board 33A side, the main capacitor charging voltage VMC
The detection variation is only ΔVMCD, and 330V ± 0.
The voltage is 72 V, which is considerably narrowed, and a highly accurate detection of the charging voltage can be performed.

In the cameras of the above embodiments, the strobe board and the camera control board are two-body, but as a modified example, the board may be further divided. In each of the above embodiments, an example of a camera having a built-in strobe is shown. However, the present invention is not limited to this. It is possible to apply the adjustment method or the structure of the invention.

Further, in the cameras of the above embodiments, the A / D
A charging voltage detection system is configured using a circuit and an EEPROM or the like, and the detection system is adjusted.
For example, a method may be used in which a circuit for detecting a voltage by a comparator is applied as a detection system, and the reference voltage is adjusted by a variable resistor, a resistor, or the like.

(Supplementary Note) Based on the above embodiments, the following built-in strobe camera and strobe device can be configured.

(1) A strobe circuit including a main capacitor, charging voltage detecting means for detecting a charging voltage of the main capacitor, and a charging voltage adjusting means for adjusting the charging voltage detecting means which is separate from the strobe circuit. And a strobe circuit incorporating the strobe circuit and the charging voltage adjusting unit after the adjustment by the charging voltage adjusting unit.

(2) A strobe circuit including a main capacitor and charging voltage detecting means for detecting a charging voltage of the main capacitor are provided, and after adjusting the variation of the charging voltage detecting means, the strobe circuit is combined with the strobe circuit. A strobe device characterized in that:

(3) A main capacitor for storing electric charge for causing the flash discharge tube to emit light, at least two or more series resistors connected in parallel to the main capacitor to divide the voltage of the main capacitor, and Charging voltage detecting means for detecting the voltage of the main capacitor; and charging voltage storing means for storing data corresponding to the charging voltage of the main capacitor, wherein the charging voltage has a predetermined value corresponding to a variation in the resistance value of the series resistor. A flash device for correcting data in a storage means.

[0038]

As described above, according to the method for adjusting the strobe charging voltage of the camera of the present invention, the charging voltage detecting system for detecting the charging voltage before the camera is assembled into the camera body. Since the value of the strobe information is adjusted, after incorporating the detection means into the camera,
It is not necessary to insert a high voltage into the camera with a test pin or the like for adjustment, and an accident such as the contact of the test pin with a control member of the camera is eliminated. At the same time, restrictions on the arrangement of the control members are reduced, and the camera can be easily downsized.

[0039]

[Brief description of the drawings]

FIG. 1 is a block diagram of a flash circuit and a camera control circuit of a camera having a flash according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a flash circuit and a camera control circuit of a camera having a flash according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram of a conventional flash device of a camera.

FIG. 4 is a circuit diagram of another conventional camera flash device.

FIG. 5 is a circuit diagram showing a concept of a main capacitor voltage detecting unit in the camera of FIG. 4;

FIG. 6 is a perspective view of the camera to which the camera shown in FIG. 4 is applied, with an exterior thereof being removed.

[Explanation of symbols]

29 EEPROM 31, 33 ...... Camera control unit assembly (shooting sequence control unit assembly) 31A, 33A ...... Camera control board (shooting sequence control unit assembly) 31B, 33B ...... Camera control circuit (shooting sequence) Control unit assembly) 32B, 34B: strobe circuit C5: main capacitor Dc: charge state determination data (strobe information) R6, R7, R36, R37: voltage dividing resistor (charge voltage detecting means) VST: …… Division resistance voltage

Claims (2)

(57) [Claims] 1. A strobe circuit base including a main capacitor.
Board and the strobe circuit board are separate and the main
Voltage detection that A / D converts and detects the charge voltage of the capacitor
Strobe charging voltage adjusting method smell camera comprising a camera control circuit board, the containing means
Te, the camera control circuit board, the flash circuit board and electric
When the camera is in a stand-alone state before it is
Connect the input terminal of the voltage detection means on the
Apply a pseudo voltage equivalent to the charge adjustment voltage of the condenser
And detecting the voltage of the voltage detecting means itself based on the pseudo voltage.
The process of adjusting the output variation and the adjustment of the charge adjustment voltage of the main
Not performed the above strobe circuit board and the above camera control
Strobe charging voltage adjusting method of a camera, characterized in that it and a step of electrically connecting the circuit board. 2. A strobe circuit base including a main capacitor.
Board and the strobe circuit board are separate and the main
Voltage detection that A / D converts and detects the charge voltage of the capacitor
Strobe charging voltage adjusting method smell camera comprising a camera control circuit board, the containing means and EEPROM
Te, the camera control circuit board, the flash circuit board and electric
When the camera is in a stand-alone state before it is
Connect the input terminal of the voltage detection means on the
Apply a pseudo voltage equivalent to the charge adjustment voltage of the condenser
And detecting the voltage of the voltage detecting means itself based on the pseudo voltage.
The data for correcting the output variation is stored in the EEPROM
And the adjustment of the charge adjustment voltage of the main capacitor by itself
Not performed the above strobe circuit board and the above camera control
Camera strobe charging voltage adjustment, characterized by having a step of electrically connecting the circuit board
Adjustment method.