JPS6239568B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that automatically sets the output state of a counter to a predetermined state.

For example, modern cameras display a lot of information in the viewfinder. One of the pieces of information is the shutter speed, and this shutter speed is predicted in advance under the aperture priority method. This allows the photographer to know the shutter speed in advance.

Generally, this type of shutter speed display means uses a counter to count the number of train pulses (continuous pulses), uses the count output of this counter to drive a matrix circuit, and uses the output of this matrix circuit to light a predetermined indicator lamp. The shutter speed is displayed using this light emission.

However, in the production process of cameras, it is necessary to set the counter to a predetermined output state in order to inspect the time characteristics. The output state of the counter can be obtained by inputting a predetermined number of train pulses to the counter, but it is difficult to stop the pulse input at an arbitrary position. The reason is that the input of the number of pulses is extremely fast.

An object of the present invention is to provide a device that electrically detects the state of input of a predetermined number of train pulses and automatically stops the input state of train pulses.

Based on the above object, the present invention continuously inputs train pulses to a counter, detects the output state of the counter with a detection circuit, and automatically changes the input state of the train pulse when the output state is a predetermined output state. I'm trying to cancel it.

Embodiments of the present invention will be specifically described below based on the drawings.

The automatic counter setting device 1 of the present invention includes a counter 3 and a matrix circuit 4 built into the camera side.
and indicator lamps 5 ₁ , 5 ₂ , .

The pulse generation circuit 2 generates a train pulse, and uses the first pulse generator 8 and the output of the first pulse generator 8 as one input, and the control output of the control circuit 7 as the other input. It consists of an AND gate 10 as an input and a second pulse generator 9 connected to the output side of the AND gate 10, and the train pulse as an output is input to the up input or down input of the counter 3. It is designed so that Counter 3 is
For example, it is an up-down type, which counts the number of train pulses of the pulse generation circuit 2,
A predetermined coded count output is generated based on the count value. The matrix circuit 4 receives the encoded output of the counter 3 as an input and selectively generates an output at a predetermined output portion. Based on the output of the matrix circuit 4, display lamps 5 ₁ , 5 ₂ , etc. such as light emitting diodes are output. ...5n is selectively lit, and the shutter speed is displayed at the lit position. The detection circuit 6 also includes the indicator lamps 5 ₁ , 5
It is selectively connected between the terminals of predetermined terminals of the matrix circuits ₂ , . _. . , 5n to detect the position of the output of the matrix circuit ₄ . The main part is a switching transistor 13 which is connected to the cathode end of the light emitting diode through the collector and emitter of the transistor, and whose base is connected to the anode of the display lamp ₅₂ , for example.
These include a resistor 12 for current limiting or voltage adjustment;
14 and an output inverter 15. Further, the control circuit 7 includes the detection circuit 6
When receiving the detection output of
It sends a control output to prohibit the generation of train pulses to the flip-flop 16.
have. The set terminal S of this flip-flop 16 is connected to ground 17 via an inverter 19 and a manual switch 18, and its output terminal Q is connected to one end of an AND gate 10, and the other output terminal is connected to a confirmation indicator lamp 20. It is connected to ground 17 through the. And the detection circuit 6
The output of the inverter 15 is connected to the reset terminal R of the flip-flop 16.

Next, the operation will be explained. Now, for example, display lamp 5
The explanation will be made assuming that the output state of the counter 3 is set to the lighting state of _{No. 2} . When all the circuits are powered on and the manual switch 18 is turned on, the "L" level signal from the switch 18 is inverted by the inverter 19 and becomes the "H" level, and the set terminal of the flip-flop 16 is turned on. It is input to S as a set input. Therefore, the flip-flop 16 generates an "H" level control output at its output terminal Q, and sends this to one input terminal of the AND gate 10 of the pulse generating circuit 2. Therefore, the train pulse of the first pulse generator 8 is
The signal is continuously inputted to the up input terminal of the counter 3 via the AND gate 10. Here, counter 3 is
The number of pulses is counted, encoded, and sent to the matrix circuit 4. The matrix circuit 4 generates an output to sequentially drive the display lamps 5 ₁ , 5 ₂ , . . . 5 n based on the output state of the counter 3 . When the output of the matrix circuit 4 becomes an output state for driving the display lamp ₅₂ , an "H" level signal appears at the base of the transistor 13 of the detection circuit 6, so the transistor 13 is instantly turned on, and its collector is turned on. An "L" level signal appears on the side. This "L" level signal is inverted by the inverter 15 and inputted to the reset terminal R of the flip-flop 16 of the control circuit 7 as an "H" level detection output. Therefore, the flip-flop 16 is immediately reset and the control output at its output terminal Q is set to the "L" level. Therefore, the first pulse generator 8
The train pulse will no longer pass through the AND gate 10 at the time of its detection, so the counter 3 will automatically stop driving the indicator lamp ₅₂ . This state can be confirmed by lighting the confirmation indicator lamp 20. If you want to sequentially shift the output state of the counter 3 by a predetermined number, for example "2" in this stopped state, operate the second pulse generator 9 and directly input two pulses of train pulses to the counter 3. Bye. In this way, counter 3 will be 2 each time.
The number of pulses is counted, and the output state is sequentially shifted by two. Of course, this number of pulses is
The number of pulses may be one or more, and therefore, the output pulse of the second pulse generator 9 may be configured so that the number of pulses of one or more can be arbitrarily selected.

After obtaining a predetermined counter output state in this way, the operation of measuring the appropriate seconds circuit for exposure control and adjusting the seconds is proceeded.

In addition, the present invention inspects the time characteristic of the camera,
Although this automatic counter setting device 1 was developed to adjust a seconds setting circuit, it is not limited thereto, and can of course be applied to circuits having other counters.

According to the present invention, since the output state of the counter can be set to a predetermined position at high speed, the operator's eyes are not fatigued and the setting operation is easy, compared to the operation of setting while checking the light emission of the indicator lamp. It has the advantage of being fast. Additionally, when the counter reaches a predetermined output state, the device automatically stops, so
Constant monitoring is not required, simplifying workability. Furthermore, since the pulse generating circuit has a means for sequentially sending out pulses by manual operation, there is also the advantage that arbitrary sequential settings from a reference setting position can be easily performed manually.

[Brief explanation of the drawing]

The figure is a block diagram of an automatic counter setting device according to the present invention. DESCRIPTION OF SYMBOLS 1... Counter automatic setting device, 2... Pulse generation circuit, 3... Counter, 4... Matrix circuit, 5
₁ , 5 ₂ , ..., 5n... Display lamp, 6... Detection circuit, 7... Control circuit, 8... First pulse generator, 9... Second pulse generator, 10... AND gate, 11... Power supply terminal, 12 ...Switching transistor, 16...Flip-flop, 1
8...Switch, 20...Confirmation display lamp.

Claims (1)

[Claims] 1. A first pulse generator that continuously generates train pulses, a second pulse generator that generates a predetermined number of pulses by manual operation, and an output side of the first pulse generator. a gate circuit connected to the second pulse generator and a counter for counting the number of pulses appearing on the output side of the gate circuit; and a counter for counting the number of pulses appearing on the output side of the second pulse generator and the gate circuit; A matrix circuit that generates a signal, a plurality of display lamps driven by the output of the matrix circuit, and a detection circuit that is selectively connected between the terminals of a predetermined display lamp among these display lamps and detects the output of the matrix circuit. and a control circuit that sends a control output for prohibiting passage of a train pulse to the gate circuit when receiving the detection output of the detection circuit. 2. In claim 1, the detection circuit is a switching transistor whose collector-emitter is connected between the power supply terminal and one end of the indicator lamp, and whose base is connectable to the other end of the indicator lamp. An automatic counter setting device characterized in that it is configured as a main part. 3. In claim 1 or 2, the control circuit includes a flip-flop that is set by manual switch operation, reset by the detection output of the detection circuit, and generates a control output at one output terminal.
An automatic counter setting device comprising a flop. 4. The automatic setting device for a counter according to claim 3, wherein the control circuit has a confirmation indicator lamp, and the confirmation indicator lamp is connected to the other output terminal of the flip-flop.