JPS5929920B2 - Counting device for mechanical displacement detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a counting device for digital information, and more particularly to a counting device for a digital control device.

That is, one of the displacements of the device is directly converted into an electrical signal by mechanical means, this pulse signal is counted, and the output is compared with other preset digital values to obtain a matching output. , relates to a counting device for use in a digital control device, with which a preset mechanical displacement is obtained by controlling said mechanical means. Conventionally, various photographic information is digitized and calculated, and the output pulse of an exposure calculation circuit that is set according to the shutter speed, film sensitivity, and subject brightness is used to control the aperture mechanism of the lens actually used for photographing. The aperture information of this lens is replaced with a resistance value, and a constant current is passed through this resistor to convert the aperture information into an electrical quantity.The analog information obtained thereby is converted into digital information by A-D conversion. A known method is to obtain aperture information by comparing the aperture information and calculation outputs from various photographic information.

The conventional device as described above requires an A-D converter and therefore has a complicated circuit configuration, which has many disadvantages when incorporated into a small camera or the like. Therefore, the aperture information used in actual photography is not obtained as analog information, but is directly generated as a digital signal, and this is used in the exposure control method that digitally controls the shutter speed or aperture mechanism. A counting device was used to count the number of contacts with the brush sliding over it. However, in the counting device, there is a counting device having a function of preventing erroneous counting of pulses generated due to a chattering phenomenon, that is, a counting device that has a function of preventing erroneous counting of pulses generated due to a chattering phenomenon, that is, a counting device that has a function of preventing erroneous counting of pulses caused by a chattering phenomenon. is not directly input to the input terminal of a counter that counts, but is input to the reset terminal of the counter, the input terminal of said counter is connected to the output terminal of a clock pulse generator, and the output of said counter is connected to a second counter output terminal. For pulses with short intervals between pulses, such as pulses input to the input terminal of the input terminal and generated by chattering, the first counter is reset each time a pulse is output, and the count of the first counter is After the chatter has subsided by prohibiting the count-up, the first counter is allowed to count up and a contact signal between the brush and the comb teeth is transmitted to the second counter;
A counting device in which the contact signals are counted by a second counter has the following problems.

In other words, when the sliding speed of the brush is extremely slow and the oscillation frequency of the clock pulse generator is extremely high, the interval between pulses generated by chatter becomes long, so the count up period of the counter is longer than the first counter set period. Before the first counter is reset by the pulse generated by the chatter, the first counter counts up the clock of the clock generator, and the second counter counts up. The drawback was that the counting was done incorrectly. In addition, due to factors such as the smoothness and elasticity of the surface of the brush and the smoothness of the step between the surface of the conductive part and the surface of the non-conductive part of the comb-tooth electrode, the chattering time when the brush and the comb-tooth electrode contact each other is reduced. It changes for each camera depending on the combination of shaped electrodes. Therefore, if the period of time during which chatter is occurring is long, after the chattering ends and the first counter is allowed to count, a predetermined count is performed and then a signal is output to the second counter. Previously, the brush has moved to the next electrode position, and as a result outputs a pulse signal with a pattern of conductive and non-conductive parts, causing the first counter to form a contact signal to the second counter. There is a drawback that the first counter has been previously set and the second counter is no longer counted.

Therefore, if the chattering time changes for a long time due to factors such as the brush surface being relatively rough and the difference in level between the conductive and non-conductive parts of the comb-shaped electrode, the chattering phenomenon described above may occur. Even if the counting device has a function of preventing erroneous counting of pulses generated by the above-mentioned pulses, there is a drawback that counting may not be performed as described above. In view of this point, it is an object of the present invention to provide a counting device as described above, which prevents chattering without being affected by the state of the conductive part or the magnitude of the sliding speed of the brush.

The present invention will be explained in detail below using the drawings.

FIG. 1 is a circuit diagram of a digitally controlled camera to which a counting device according to the present invention is applied.

In FIG. 1, I is a photoelectric conversion element 34b1 having a high optical response speed, such as a silicon photocell, and an operational amplifier 2.
″, a logarithmic compression diode 3′ inserted in its return path.
This is a photometry section consisting of. 4″ is the A-D converter and photometry section 1
Converts analog output to digital value.

5'' is a memory section consisting of a register, and a memory switch SM
Stores the digital output when the is on.

6'' adds the subject brightness information Bv of the adder register 5'' and the logarithmically compressed and digitized film sensitivity information Sv.

7" is a subtracter, and the output of adder 6" is used as one input, and the other input is a switch Sp.
Logarithmically compressed and digitized shutter speed information Tv is inputted via a shutter speed control switch ST, and in the case of aperture priority P, logarithmically compressed and digitized aperture information Av is inputted via a shutter control switch ST.

12' is a register, and when the shutter has first priority, Av is,
Further, when aperture priority is given, Tv is stored.

10'' is an aperture step number pulse generation circuit which generates a step number pulse in conjunction with the aperture mechanism of the lens.

Sp is a manual switch that is turned on when the shutter is given priority. A register 1t stores the output pulse from the pulse generating circuit 10' via a switch Sp.

9'' is a comparison circuit which generates an output pulse when the aperture value stored in the register 1Z matches the pulse signal of the register 1V, and activates the aperture control magnet Mg? via the switch SD.

8'' is a delay circuit that drives the 7 magnet Mg3 for the front curtain when the mirror finishes rising after the shutter release.

14'' is a delay circuit which drives the trailing curtain magnet Mg4 after the shutter time of one second set therein and after the calculated shutter time of one second.

13 is a register, A is a shutter dial, L is a lamp, SD is a magnetic switch that works with the manual switch Sp, and ST is a pulse signal that is connected to register 13''.
Is this the shutter control switch, ST? It is a switch that works with the.

Sp is the display switch, and the lamp switch SL, SL
・Sw is a manual control switch that transmits shutter speed information to the 1-time constant circuit during manual operation.

Figure 2 shows the aperture stage number pulse generation circuit 10'' in Figure 1.
and! 1 is a circuit system diagram showing a conventional example of a counting device shown in FIG.

In the figure, reference numeral 101 denotes a comb-like conductor pattern, in which a conductor as shown made of a metal film or the like is disposed on an insulating substrate (not shown), and a brush 102 slides over this pattern.
slides in the direction of the arrow, and the contact between the conductor and the brush generates a pulse signal. 103 is a conductive pattern for generating a start signal placed at one end of the pattern 101, and the sliding brush 102 starts from this position and slides on the comb-like pattern.

104 is a first binary counter, and the signal from the brush 101 is applied to the clear terminal of 104 to count the clock pulses input from the CP terminal.

A clock pulse generator 105 is composed of, for example, an astable multi-pipe radar, and generates pulses of a constant period.

106 is an AND gate whose output is input to the CP terminal of 104 above.

The first counter 104 is controlled by the signal from the brush 102 to count the clock pulses from the CP, and outputs the binary code pulses to its output terminals "1", "2", "4", and "8". produces an output.

Among the outputs of the counter 104, the output pulse of the terminal "4" is inputted to the CP terminal of the second counter 108, where the output pulse of the terminal "4" is inputted to the CP terminal of the second counter 108.
It is counted in decimal numbers. Further, the pulse from output terminal "8" of 104 is input to the AND gate via inverter 107, forming a closed loop. The output of the second counter 108 is input to a comparator 109, and the other input of this comparator 109 receives a digital brisset signal from a brisset signal source 110 for photographing information, and these signals are compared at 109. When there is a match, output 109 occurs. The output from comparator 109 is mechanically represented by electromechanical conversion means 111. In the embodiment shown in FIG. 4, a 7-bit binary counter, for example, is used as the first counter 104'', and the output terminals of the 7-bit binary counter are connected to the second counter 108 through an OR gate. is inputting to. In this circuit, similar to the one in Figure 2, the outputs of the counter's "1" and "2" terminals are not used in order to eliminate the influence of brush chatter.
An input signal to the second counter 108 is generated from all outputs after the ``4'' terminal. Even if the sliding speed of the brush is quite slow, by using a 7-bit counter 104', the output of the counter 104' will be cleared by the signal from the next brush while the counter counts one clock pulse. The signal is a number corresponding to the number of contacts between the brush and the pattern.If the sliding speed of the brush is extremely slow and the period of the clock pulse is extremely fast, the counter output will be 2 or more for the number of contacts of the brush. 5 is a circuit system diagram showing one embodiment of the present invention, and FIG. 6 is a curve diagram showing an example of a timing chart of the circuit of FIG. 5.

In the figure, the same parts as in FIG. 2 are designated by the same reference numerals. In this embodiment, the clock pulse generator 105'' uses a variable frequency type, and the first counter 104 uses a 4-bit type, and the signal from its output "8" is used as the CP of the second counter 108. input to the terminal. Note that 200 is a variable resistor that changes the oscillation frequency of the clock pulse generator 105. The operation of this circuit is performed by varying the frequency of the clock pulse shown in FIG. 6a in accordance with the sliding speed of the brush.
The outputs of 1 to 15 form the input signal to the second counter 108. By changing the frequency of the clock pulse according to the brush speed in this way, even if the brush speed is fast or slow, only one 104 output signal can be generated for one touch, so malfunctions will not occur. become. Figure 6b
is the case where the brush speed is the fastest; in this case, the signal c is generated only by the output of count 8 among the 104 outputs, and is cleared after count 9. Figure d shows the case where the brush speed is the slowest, and in this case, the frequency of the clock pulse becomes slow and the signals from count 8 to count 15 of the outputs 104 form a signal as shown in figure e. FIG. 7 is a plan view a showing an example of a comb-like conductor pattern used in the counting device of the present invention, and a curve diagram b showing brush sliding characteristics.
It is.

In the figure, 101 is a comb-shaped conductor pattern, 102 is a sliding brush, 103 is a start position signal pattern, 21
2 is a common return pattern, 113 is an insulating substrate, 114, 1
15 is a connecting conductor from the pattern. These patterns 101, 103, and 212 are fixedly disposed on an insulating substrate 114 using a conductor piece or a method such as vapor deposition, and the sliding brush 102 moves on the pattern with uniform acceleration from the starting position S to the right as shown in FIG. Sliding. Reference numeral 103 is a start pattern arranged independently at the sliding start position of the brush, and by sliding this, a start position signal is obtained, and with this, the second In addition to clearing the counter, it also serves to reduce wear in the first pattern of the comb-like pattern 101.

212 is a common return pattern provided in parallel to the comb-like pattern 101;
115 are drawn out from opposite ends as shown.

This prevents the resistance value within the pattern from changing depending on the sliding position. In the figure, P and Q are the conductor widths in the sliding direction of the comb-like pattern, and the widths are changed in accordance with the brush speed shown in Figure b. Also figure Af
)e-n is the stopping position without taking into account the sliding speed of the sliding brush, and on the other hand, the position of the comb teeth of the pattern as shown in R, U, and V in the figure is corrected forward as shown in e' to n'. It is arranged as follows. This is to compensate for the time delay caused by the electromagnetic magnet that causes the brush to stop, other mechanical delays in the drive mechanism, etc. In Fig. 7b, α is the acceleration when the brush is moving at a constant acceleration, S/ is the distance from the start position of the position where the brush actually slides and stops after the pulse generation, and the above-mentioned time at this time. The distance from the start position of the T1 pulse generation position is the delay, t is the time from S1 start to the pulse generation, and the interval between each stop position is 11.
If the number is n, then the pulse generation position S is s=1αT2
(1), and the actual stopping position S' is expressed as S=-α(t-T)2 (2),
This is equal to nl.

By subtracting equation (1) from equation (2), the distance to be corrected can be obtained.

In other words, the corrected distance ΔS is Δs=s−s=↓α(2tT+T2
) (3) S in equation (3)! =nl=↓α(2tT+T2)
Substituting the relationship and eliminating t yields ゛.

In equation (4), l is constant, so if we calculate R, U, V, etc. shown in the figure according to N, α, T and find the correction distance due to the delay, then the comb tooth The shape of the pattern is determined. Note that Figure BO) m (hereinafter, it is a constant velocity motion, so the pattern for this will be a pattern with equal intervals. Figure 8 shows the sliding brush 102 between the comb-like conductor pattern 101 and the common return path pattern 212). By arranging both patterns as shown in FIG. 7 and FIG. 8 a, it is necessary to use a brush with a simple structure as shown in FIG. In terms of the above and other aspects, the cost will be higher than that shown in FIG. 8a.

In this embodiment, the comb-shaped electrode 101 is used as a pulse signal generating means that generates pulses corresponding to the number of contacts that the brush and the contacts make contact with by sliding the brush against the comb-shaped conductor contacts. and brush 102.

The output of the pulse signal generating means was input to the reset terminal, and the output of the clock pulse generator was input to the input terminal, forming a first binary counter 104 as a first counter.

A second counter 108 was connected to the output terminal of the first counter.

A variable resistor 200 is used as means for changing the frequency of the clock pulse output from the clock pulse generator. As described above, according to the present invention, the pulse signal generating means generates pulses corresponding to the number of contacts that the brush and the contacts come into contact with by causing the counting device to slide the brush against the comb-like conductor contacts. and a clock pulse generator.
a first counter having an output of the pulse signal generating means inputted to a reset terminal and an output of the clock pulse generator inputted to an input terminal; a second counter connected to the output terminal of the first counter; Since the clock pulse generator includes a means for changing the frequency of the clock pulse outputted from the clock pulse generator, the means for preventing chattering of a counting device for counting mechanical displacement, for example, by sliding the comb-shaped electrode and the brush. That is, a clock pulse generator, a first counter having the output of the pulse signal generating means inputted to the reset terminal, the output of the clock pulse generator inputted to the input terminal, and connected to the output terminal of the first counter. In the case where the brush sliding speed is extremely slow and the frequency of the clock pulse is extremely high, the first counter is set by the signal from the pulse signal generating means. The counter counts up the clock of the clock generator, causing the counting of the second counter to malfunction (this can be prevented by changing the oscillation frequency of the clock generator according to the sliding speed of the brush). It is very effective.

In addition, malfunctions of the counting device caused by chattering time that varies from camera to camera due to the smoothness and elasticity of the surface of the brush, the smoothness of the step between the surface of the conductive part and the surface of the non-conductive part of the comb-shaped electrode, etc. do not occur. Thus, the frequency of the clock pulse of the clock pulse generator can be adjusted during manufacturing, which is very effective.

[Brief explanation of drawings]

FIG. 1 is a circuit connection diagram showing an example of a digital control camera to which a counting device according to the present invention is applied, FIG. 2 is a circuit diagram showing an example of a counting device to which the present invention is applied, and FIG. FIG. 4 is a circuit diagram showing another example of a counting device to which the present invention is applied, and FIG. 5 is a circuit diagram of an embodiment of the present invention. , FIG. 6 is a curve diagram showing an example of the timing chart in the circuit of FIG. 5, FIG. 7 is a curve diagram showing the comb-like conductor pattern and sliding characteristics used in the counter of the present invention, and FIG. FIG. 3 is a perspective view showing the arrangement of a comb-tooth conductor pattern, a common return pattern, and a sliding brush. 1...Photometering section, 7...Operation amplifier, 3
′・・・Logarithmic compression diode, 4″・・・・・・
・A-D converter, 5'... Storage section, 6'...
...Adder, 7'...Subtractor, 8'...
...Delay circuit, q...Comparison circuit, 107...
...Pulse generation circuit, 1V, 12', 131...
・Lujistor 1, 14t...Delay circuit, A...
...Shutter dial, L... Lamp, SD
...Magnetic switch, SM...Memory switch, ST...Shutter control switch, ST/...Switch that works with ST, Si)
・・・・・・Manual switch, Sp/・・・・・・
Display switch, Spl...Shutter priority selection switch, SL, SL'...Lamp switch, Sw manual control switch, Mg2...
...Aperture control magnet, Mg3...Magnet for front curtain, Mg4...Magnet for rear curtain, S
v... Film sensitivity information, Tv... Shutter speed information, 34b... Photoelectric conversion element,
101... Beveled conductor, 102... Sliding brush, 103... Start position conductor, 10
4,104'...First counter, 105...
...Clock pulse generator, 106...AN
D gate, 107... Inverter, 108.
...Second counter, 109...Comparator,
110... Briset signal source, 111...
...Electrical-mechanical converter, 112...OR circuit,
105'...Variable frequency pulse generator, 113.
...Insulating substrate, 114, 115...Connection conductor, 200...Variable resistor.

Claims (1)

[Claims] 1. A start position conductor, a comb-shaped conductor contact consisting of a number of contacts located at a predetermined interval in a predetermined direction in contact with the start position conductor, and a comb-shaped conductor contact that slides on the contact to a position according to the amount of mechanical displacement. a pulse signal generating means having a brush and generating pulses according to the number of contacts that the brush and the contacts contact; a clock pulse generator; and an output terminal of the pulse signal generating means connected to a reset terminal; Connect the output terminal of the clock pulse generator to the counting input terminal.
The first output terminal is a predetermined digit output terminal of the output terminal.
and a second counter having a counting input terminal connected to the output terminal of the first counter, and in which the mechanical displacement amount is converted into a digital value signal. A counting device for a mechanical displacement amount detection device, characterized in that the counting device is equipped with means for changing the frequency of a clock pulse outputted to a clock pulse generator to prevent malfunction of counting.