JPH0625851B2 - In-camera information confirmation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to various kinds of information inside a camera, and in particular, information inside a camera that allows a camera exposure information signal value to be easily checked during camera assembly and maintenance. The present invention relates to a confirmation device, and more specifically, to a device that allows camera exposure information to be confirmed from the outside by using a DX code input electrical contact.

[Prior Art] In recent years, cameras have been automated, and therefore various amounts have been digitized for exposure calculation, automatic film winding, automatic ISO sensitivity reading of used films, various displays, and the like. For example, even for automatic exposure with priority on aperture value, the set aperture value, field brightness value, and film sensitivity value are converted to digital quantities and a predetermined apex operation is performed, and the resulting values are reconverted to analog quantities and the shutter is released. Adopt a configuration that controls the time. However, for example, in the case of the brightness value, there is an error due to the mounting position of the light receiving element and the offset of the A / D conversion circuit. Therefore, it is necessary to electrically eliminate this error, particularly the offset error, at the time of inspection at the camera assembly stage. There is.

Further, as a device for transmitting the sensitivity value of the film used to the arithmetic circuit in the camera, as shown in FIGS. 7 and 8, predetermined positions 10a, 10b, 10c, 10 on the outer surface of the film 10 film cartridge are used.
Conductive or non-conductive material is applied to d and 10e according to its sensitivity value, while at the above-mentioned predetermined position at the camera film mounting location.
Electrical contacts 12a, 12b, 12c, 12d, at positions corresponding to 10a, ..., 10e
A device provided with 12e has been proposed (for example, JP-A-59-59).
See 211027). In this configuration, these electrical contacts 12a,
..., 12d (however, the contact 12e is for grounding), the camera side arithmetic circuit can automatically read the film sensitivity value depending on whether or not the contact 12e is electrically contacted via the conductive material on the cartridge. it can.

[Problems to be Solved by the Invention] In a circuit that converts an analog amount into a digital amount and performs an operation, it is essential to adjust the A / D conversion circuit, particularly the offset value thereof. However, in the exposure control circuit, for example, in the case of the aperture value priority type, after the necessary electronic circuit including the light receiving element is assembled in the camera, the exposure determination calculation is actually performed to see the aperture value Av, the field The circuit was adjusted by checking whether or not the brightness value Bv or the like was properly used for calculation.
However, in such a checking method, when Av and Bv have errors in different directions, those errors do not appear in the exposure value. The only way to find these errors was to make multiple exposure calculations under different conditions and make an overall adjustment. Since the digital circuit for exposure calculation is usually realized by a microcomputer, it is not easy to check each digital amount. Also, even if each digital signal line is exposed to the outside, it is difficult to properly position the checking probe and to do this without damaging the circuit, because the circuit itself is made small. It was

In the case of a camera, since the electronic circuit is hermetically sealed inside the camera housing, it is quite difficult to perform maintenance and inspection regarding changes in offset error and the like.

Therefore, an object of the present invention is to propose an apparatus that can easily confirm various information inside the camera, particularly exposure information used for exposure calculation, as digital values.

[Means for Solving the Problems] A confirmation device according to the present invention includes a plurality of electric terminals for reading a DX code of a film by determining a shooting condition enabling shooting with a desired exposure value by a digital arithmetic circuit. In a camera, a switch means and a switch used by a digital arithmetic circuit in response to a switching signal from the switch means 1
And a circuit for outputting a bit of various information inside the camera to an electrical terminal for reading a DX code.

Embodiments The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram of an example in which the present invention is applied to a camera of an aperture priority automatic exposure system. Reference numeral 20 is a main arithmetic circuit that performs the exposure calculation and also performs the main function of the present invention. Reference numeral 22 is a light receiving element that receives the field light and generates an electric signal corresponding to the amount of light. The well-known Bv conversion circuit 24 including a logarithmic compression circuit converts the output of the light receiving element 22 into an amount suitable for the apex operation in the subsequent stage. To the Bv conversion circuit 24, a Bv adjustment volume 26 for absorbing an attachment error of the light receiving element 22 and an offset error of the A / D conversion in the subsequent stage is connected. The A / D converter 28 converts the analog signal of the conversion circuit 24 into a digital signal, and the Bv buffer memory 30
To memorize. The output of the Bv buffer memory 30 is connected to the input port of the main arithmetic circuit 20.

Reference numeral 32 denotes a variable resistor whose resistance value changes according to the diaphragm operation of the diaphragm operation ring, and the Av conversion circuit 34 converts this resistance value into an amount suitable for the apex operation in the subsequent stage. An Av control volume 36 for absorbing an offset error of A / D conversion in the subsequent stage is connected to the Av conversion circuit 34.
The A / D converter 38 sequentially converts the analog signal of the Av conversion circuit 34 into a digital signal and stores it in the Av buffer memory 40. The output of the Av buffer memory 40 is connected to the input port of the main arithmetic circuit 20.

Electrical contacts 12a, 12b for reading the DX code shown in FIG.
12c and 12d are connected to the input ports of the main arithmetic circuit 20 via buffers 14a, 14b, 14c and 14d, respectively. The electrical contact 12e is connected to ground. As a result, the sensitivity value of the film used is input to the main arithmetic circuit 20.

Further, the output port of the main arithmetic circuit 20 is connected to the electrical contacts 12 via the tri-state buffers 16a, 16b, 16c and 16d, respectively.
Connect to a, 12b, 12c, 12d. In addition, the main arithmetic circuit 20
From the output port of the v value and the Av value, the electrical contacts 12a, ..., 1
A changeover switch 42 for forming a changeover signal for changing over to the operation for outputting to 2d is provided. One end of the changeover switch 42 is connected to ground, and the other end is connected to a constant voltage via a pull-up resistor 44. The changeover signal of the changeover switch 42 is the main arithmetic circuit 20.
16d, and connected to the control terminals of the tri-state buffers 16a, ..., 16d via the inverter 46. The output impedance of the tri-state buffers 16a, ..., 16d becomes large when the control terminal has a low voltage.

The main calculation circuit 20 calculates a value Tv relating to the shutter speed according to the following equation for the exposure calculation: Tv = Bv + Sv-Av
The count value related to the v value is supplied to the shutter drive circuit 50. The shutter drive circuit 50 turns off when the shutter opens.
It will be activated by the switch 52, and from this count value,
A well-known shutter control signal, for example, a signal having a time width corresponding to the shutter second is formed to control the shutter control magnet 54. The switch 52
Turns on when the film is wound up. The structure itself of this shutter mechanism portion is publicly known and is not directly related to the present invention, and therefore further description is omitted.

FIG. 2 is a diagram showing an equivalent electric circuit of the insulator and the exposed conductor applied on the outer peripheral surface of the film cartridge 60 according to the film sensitivity value. Electrodes 62a, 62b, 62c,
62d and 62e are in contact with the electric contacts 12a, 12b, 12c, 12d and 12e, respectively, in a state where the film is mounted on the camera. Electrode 6
The fact that 2b and 62d are not connected to the electrode 62e indicates that the positions corresponding to the electrodes 62b and 62d of the cartridge are non-conductive.

Returning to FIG. 1, reference numeral 70 denotes an electric contact 12a from the main arithmetic circuit 20.
, 12d conceptually shows a display device for displaying the exposure information of Bv and Av output to 12d. Electrode 72a,
72b, 72c, 72d and 72e are electrical contacts 12a, 12b, 12c and 12 respectively.
It is provided at a position facing d, 12e and has electrical contacts 12a, ..., 12
The voltage state on d can be confirmed by the LEDs 74a, ..., 74d. Of course, instead of LEDs, oscilloscopes, logic analyzers, etc. may be used.

FIG. 3 is a block diagram for explaining the main arithmetic circuit 20 in more detail. However, it should be noted that the function of the main arithmetic circuit 20 of the present invention is actually realized by the microcomputer, and that FIG. 3 is a block diagram for explaining the function. . In FIG. 3, reference numeral 80 is a sequence controller for controlling a series of operations of the main arithmetic circuit 20. However, for convenience of description, some control signals to each element are omitted. 82
Is a ROM that contains program software that defines the operation of the sequence controller 80. The sequence control 80 sends the Bv value of the Bv buffer memory 30 to the switching gate 90 via the input port 84. Write to a predetermined address in the memory 92, send the Av value of the Av buffer memory 40 to the switching gate 90 via the input port 86, write to the predetermined address in the main memory 92, buffer 14a, ... Then, the DX code from 14d is sent to the switching gate 90 and written in a predetermined address of the main memory 92. 96 is an address register for addressing the main memory 92.

When the changeover switch 42 for changing the operation mode is open, it is time to perform a normal exposure calculation.
The controller 80 converts the DX code value in the main memory 92 into the film sensitivity value Sv suitable for the apex operation,
From Av, Bv and Sv, shutter time Tv (= Bv + S
Let v-Av) be calculated. This calculation is performed by the adder / subtractor circuit 94. The operation of converting the DX code into the Sv value may be performed immediately after writing the DX code in the main memory 92.
Further, this conversion may be performed by using a table reference technique to obtain the Sv value.

After the Tv value is obtained, a count value suitable for determining the shutter speed is calculated and sent to the data conversion circuit 98. The data conversion circuit 98 uses this count value as the shutter drive circuit.
The signal format is converted into a signal format suitable for 50 and sent to the shutter drive circuit 50.

When the changeover switch 42 for changing the operation mode is closed, the sequence controller 80 reads out the Av value and the Bv value stored in the main memory 92 to the output port 100. At the same time, closing the transfer switch 42 activates the output port 100 and disables the input port 88. 102 is an inverter.

There are various modes of outputting the Av value and the Bv value from the output port 100. For example, the output port 100 may convert a parallel signal into a serial signal and serially output the Av value and the Bv value in order from any one of the lines 100a, ..., 100d.
In this case, the other lines 100a, ...
Alternatively, it is used as a discrimination signal for Av and Bv. One may be used for the Av value and the other one may be used for the Bv value. Also, A
.., 100d may be transmitted sequentially for each of a plurality of bits on the lines 100a, ..., 100d, and then the Bv value may be similarly transmitted.

It is preferable to output the signal indicating which of the Av value and the Bv value is being output and the synchronization signal together, but if the output from the output port 100 is low speed, either or both of these signals may be output. You don't have to.

FIG. 4 is a flow chart showing the operation of the embodiment shown in FIG. First, the state of the changeover switch 42 is read (block 110). If it is open (OFF), a normal exposure calculation routine is selected, and if it is closed (ON), the confirmation routine of the present invention is performed.

In a normal exposure calculation routine, first, the latest exposure information necessary for exposure control must be read. Therefore,
Subroutine A reads the latest aperture value Av and stores it in a predetermined location in the main memory 92 (block 112), and then subroutine B reads the latest field luminance value and reads it in the main memory.
It is stored in a predetermined location of 92 (block 114), the DX code is read by the subroutine S and converted by a predetermined amount, and then stored in a predetermined location of the main memory 92 (block 116), and the Tv value is calculated using these values. It is calculated (block 118) and sent to the data conversion circuit 98. As long as the changeover switch 42 is open,
Repeat this.

In the confirmation routine, after the latest aperture value is stored in the main memory 92 by the subroutine A (block 120), this is read out to the output port 100 (block 122), and the latest field brightness value is obtained by the subroutine B in the main memory 92. (Block 124) and then output it to the output port 100 (block 126). This is repeated as long as the changeover switch 42 is closed.

FIG. 5 shows another embodiment of the present invention. FIG. 6 is a detailed block diagram of the main arithmetic circuit 20. This embodiment differs from the embodiment of FIG. 1 in the following points. First of all,
In addition to the electrical contacts 12a, ..., 12d for reading the DX code, an output terminal 13 indicating which of the Av value and the Bv value is being output.
0 is set separately. Secondly, instead of the changeover switch 42, a combination of the self-timer setting switch 134, the bulb photographing setting switch 136 and the switch setting judging circuit 138 for detecting the states of both switches is used. Output terminal 130
Specifically, a flash X contact or a contact for a signal exchanged between the flash device and the camera body, for example, a flash charge completion signal, a flash stop signal, or the like may be used. Since these contacts are exposed to the outside, it is preferable to connect the protection circuit 132 in order to prevent an accident such as a short circuit. As the signal of the output terminal 130,
For example, Av is used for the electrical contacts 12a, ..., 12d for reading the DX code.
A signal that becomes high when outputting a value and becomes low when outputting a Bv value is used. As a result, on the display device 70 and the analysis device side, electrical contacts for reading the DX code are provided.
It is possible to determine whether the signals on 12a, ..., 12d are Av or Bv.

When the switch setting determination circuit 138 detects the setting of the self-timer and the selection of bulb shooting (such a combination cannot be selected in normal shooting), the switch setting determination circuit 138 determines that the changeover switch 42 is closed. The same signal as is sent to the inverter 46 and the main arithmetic circuit 20. According to this combination, it is not necessary to provide a special switch called the changeover switch 42.

In both the embodiments of FIGS. 1 and 5, when the number of bits of the information Av and Bv to be output is large, it may not be possible to output the parallel signals at once with the number of DX contacts. In this case, for example, It is only necessary to divide the output into several bits, such as the upper several bits of the information and the next lower several bits. When the Bv value is 6 bits and the DX contact can use only 4 contacts (12e for GND) of the electrical contacts 12a, ..., 12d, the 6 bits are divided into the upper 3 bits and the lower 3 bits, and the output terminal 130 / Higher bits due to low /
The lower bits may be distinguished in timing.

Further, the output format of the Av value and the Bv value may be partially parallel as described above or fully serial. In that case, one or more of the DX code reading contacts is used for distinguishing the content of data to be output (for example, indicating whether Av or Bv should be output), for synchronizing signals, and for distinguishing upper bits / lower bits. Used for. Of course, the output terminal 130 may also be used. For example, the electrical contact 12d for reading the DX code in FIG.
Is used to instruct the main arithmetic circuit 20 which of Bv and Av should be output (for this purpose, the associated tri-state buffer 16d is removed), and the output terminal 130 is used for the synchronizing signal. . And in sync with this sync signal,
The upper bit and the lower bit are sequentially output to the electrical contacts 12a to 12c for reading the DX code. Although the aperture priority exposure circuit has been described, the present invention is also applicable to a shutter priority type or so-called program exposure.

Further, in the above embodiment, the case where only the exposure information (Bv value or Av value) is read to the outside through the DX terminal is shown, but the information read to the outside is not limited to this, and the following is also the same. It can be read by using the circuit configuration.

Camera power supply voltage information As shown in FIG. 9, for example, a switch device 23 for checking the power supply voltage is provided between the Bv conversion circuit 24 and the A / D converter 28, and is switched by the control signal from the main arithmetic circuit 20. The power supply voltage is checked by switching the switch of the device 23. This switch is normally connected to the Bv conversion circuit 24 side, but is switched to the power supply side by the control signal and transmits the voltage of the power supply to the main arithmetic circuit 20. Since this information is output from the DX terminal in the same path as the exposure information, the drop in the power supply voltage can be checked by this.

Operation check of timing switches, etc.As shown in FIG. 10, in the opening / closing operation of the timing switches 81, short circuits and conduction defects due to defective solder of the switches are detected, and the voltage change is digitized electrically and mechanically. Write to main memory 92 via input port 85 and switching gate 90 and D via output port as above
Since it is output to the X terminal, it is possible to check the operating state of the timing switch and the like.

Confirmation of display in the finder The output from the display circuit for turning on the LEDs in the finder is written in a predetermined address of the main memory 92 in the same manner as described above, and is addressed to the DX terminal via the output port by the address designation from the sequence controller 80. If read,
You can check the display in the viewfinder without looking through the viewfinder.

Output average value of exposure information (for example, Tv value) As described above, the exposure information calculated by the addition / subtraction circuit 94 is averaged by the addition / subtraction circuit 94, and the averaged exposure information is output to the DX terminal via the output port. Then, this DX terminal can be connected to an external computer to have a communication function.

Output of the number of shots Main operation circuit 20
The counter is stored in the memory as a count, and the count value is output from the DX terminal to check the durability.

Outputs the time from the start to the end of release The main operation circuit 20 has a clock function to start the count upon receiving a release start signal generated via the release switch etc., and a release end signal generated via the mirror up etc. In response to this, if this count is stopped and the count number up to that point (the time from the start to the end of the release) is output, the followability of the motor drive can be confirmed according to this data.

Similar to the output of the charging time of the flash, the main arithmetic circuit 20 has a clock function, the flash off signal is received by the main arithmetic circuit 20 via the output terminal 130 and the counting is started. The charging time can be confirmed from the outside by stopping the operation and outputting the counted number up to that time to the DX terminal as the flash charging time.

In this way, the sequence controller 80 is operated in accordance with the instruction of the software written in the program ROM 82 to specify the various information described above to be written in a predetermined address in the main memory 92, and the output port 10
Read out from the DX terminal via 0, various adjustment,
Confirmation work can be performed.

Although an example in which there are four electrical terminals for reading the DX code (and one for GND) is shown, the number of terminals is not limited to this, and only one for distinguishing the high-sensitivity film and the low-sensitivity film. When there are only electrical contacts, there are cases where there are 10 or more electrical contacts in order to distinguish various films. When there are many electric contacts, some of them are Av value, Bv
Value and Tv value, and other electrical contacts can be used for synchronizing signals and for indicating signals which exposure information should be output. When used for this instruction signal, the linked tri-state buffer is an obstacle,
Remove it.

[Effects of the Invention] As can be seen from the above description, according to the present invention, various digital information can be output from the electrical contacts exposed to the outside of the camera housing. The presence of can be easily confirmed and adjusted. Therefore,
Adjustment work during manufacturing and assembling is simplified, and inspection during maintenance can be performed very easily.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a confirmation device according to the present invention, FIG. 2 is an equivalent circuit diagram of a film patrone with a DX code, and FIG. 3 is a main part of the embodiment of FIG. FIG. 4 is a block diagram of the arithmetic circuit, and is a simple flowchart of the operation of the embodiment. FIGS. 5 and 6 are block diagrams of another embodiment, FIG. 7 is a perspective view showing the outer shape of a Patrone with a DX code attached, and FIG. 8 is a camera with a back cover opened to attach a film. 9 is a perspective view showing a state of performing
FIG. 10 is a block diagram of a main part of an embodiment in which a power supply voltage checking device is incorporated in the checking device shown in FIG. 1, and FIG.
FIG. 9 is a block diagram of a main part of an embodiment in which an operation confirmation device such as a timing switch is incorporated in the means arithmetic circuit shown in the figure. 12a, 12b, 12c, 12d, 12e ... Electrical contacts for reading DX code 14a, 14b, 14c, 14d ... Buffers 16a, 16b, 16c, 16d ... Tri-state buffer 20 ... Main arithmetic circuit, 22 ... Photo detector 23 ... Switch device, 24 ... Bv conversion circuit 26 ... Adjustment volume, 28 ... A / D converter 30 ... Bv buffer memory 32 ... Variable resistance, 34 ... Av conversion circuit 36 ... Av adjustment volume, 38 ... A / D converter 40 ... Av buffer memory 42 ... Changeover switch, 44 ... Pull-up resistor 46 Inverter, 50 ... Shutter drive circuit 52 ... Switch 54 ... Shutter control magnet 60 ... Film patrone 62a, 62b, 62c, 62d ... Electrode, 70 ... Display device 72a, 72b, 72c, 72d, 72e ... Electrodes 74a, 74b, 74c, 74d ... LED 80 ... Sequence controller 81 ... Timing switch 82 ... Program ROM, 84, 86, 88 ... Input port 90 ... Switching gate, 92 ... Main memory 94 ... Addition / subtraction circuit, 98 ... Data conversion circuit 100 ... Power port 102 ... inverter 130 ... output terminal 134 ... self-timer setting switch 136 ... bulb exposure setting switch 138 ... switch setting determination circuit

Claims (1)

[Claims] 1. A camera having a plurality of electric terminals for reading a DX code of a film, which is determined by a digital arithmetic circuit for a shooting condition that enables shooting at a desired exposure value,
It is provided with a switch means and a circuit for outputting a bit of various information inside the one or more cameras used in the digital arithmetic circuit to the electrical terminal for reading the DX code in response to a switching signal from the switch means. In-camera information confirmation device.