JPS6153642B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanical displacement amount detection device, for example, a mechanical displacement amount detection device applied to an exposure control device of a digitally controlled camera.

More specifically, when digitally controlling a camera, this mechanical displacement amount detection device directly converts the mechanical exposure control amount into an electrical pulse signal, counts this pulse signal, and outputs the output and various shooting information. The mechanical exposure control amount is set by comparing the digital calculation value or the digital value of the preset photographic information and stopping the displacement means of the mechanical displacement amount detection device based on the comparison result. This is for digital control.

Conventionally, various photographic information was digitized and calculated.
When controlling the aperture mechanism of the lens actually used for photography using the output pulses of the exposure calculation circuit, which are set according to the shutter speed, film sensitivity, and subject brightness, the aperture information of the lens is replaced with a resistance value. The aperture information is converted into an electrical quantity by passing a constant current through the diaphragm, and the analog information obtained by this is converted into digital information by A-D conversion, and this is compared with the calculation output from various shooting information. A method of obtaining aperture information is known. 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.

For example, the present invention directly generates aperture information used in actual photography as a digital signal without obtaining it as analog information, thereby providing mechanical information that can be applied to exposure control devices that digitally control the shutter speed or aperture mechanism. The purpose of the displacement detection device is to move a movable member that moves with a predetermined acceleration a plurality of position detection contacts arranged in a predetermined direction from a start position contact. an electric signal is generated to bring the moving member into a predetermined state when the moving member passes through a contact point for In order to compensate for the delay, there is provided a mechanical displacement amount detection device configured to gradually increase the interval between the contacts for position detection from the start position according to the acceleration of the moving member to obtain an accurate amount of mechanical displacement. It's about doing.

The present invention will be explained in detail below with reference to the drawings. FIG. 1 is a circuit diagram of a digitally controlled camera to which a mechanical displacement detection device according to the present invention is applied. In the figure, reference numeral I denotes a photometric section consisting of a photoelectric conversion element 34b with a fast optical response speed such as a silicon photocell, an operational amplifier 2, and a logarithmic compression diode 3' inserted in its feedback path. 4' is an A/D converter which converts the analog output of the measuring instrument I into a digital value. Reference numeral 5' denotes a storage section consisting of a register, which stores the digital output of the A-D converter 4' when the storage switch S _M is in the on state. 6' is an adder which adds the subject brightness information B _V in the register 5' and the logarithmically compressed and digitized film sensitivity information S _V. 7' is an arithmetic unit which serves as one input of the output of the adder 6', and the other input receives logarithmically compressed and digitized shutter speed information T _V via a switch SP _' ' in the case of shutter priority. In addition, in the case of aperture priority, logarithmically compressed and digitized aperture information A _V is input via the shutter control switch _ST . 12' is a register, in which A V is input when shutter priority is selected, and T _{V is} input when aperture priority is selected. is stored. 10' is an aperture step number pulse generation circuit that generates a step number pulse in conjunction with the lens aperture mechanism. S _P
is a manual switch that is turned on when priority is given to shutter. A register 11' stores the output pulse from the pulse generating circuit 10' via a switch _SP . 9' is a comparison circuit that compares the aperture value stored in register 12' with register 1.
1', an output pulse is generated and the diaphragm control magnet Mg ₂ is operated via the switch S _D. 8' is a delay circuit that drives the magnet Mg ₃ for the front curtain when the mirror finishes rising after the shutter release. Reference numeral 14' denotes a time setting circuit, which drives the trailing curtain magnet Mg ₄ after the shutter time set in this circuit and after the calculated shutter time. 13' is a register,
A is a shutter dial, L is a lamp, S _D is a magnetic switch that works with the manual switch S _P , S _T is a shutter control switch that transmits a pulse signal to the register 13', and S _T ' is this S
It is a switch that works with _T.

S _P ′ is the display switch, and the lamp switch S
_L and S _L ' are interlocked, and S _W is a manual control switch that transmits shutter speed information to the timer circuit during manual control.

FIG. 2 is a circuit diagram showing an embodiment of a counting device to which the mechanical displacement amount detecting device according to the present invention, shown as the aperture stage number pulse generating circuit 10' in FIG. 1, is applied. In the figure, reference numeral 101 denotes a comb-like conductor pattern constituting a mechanical displacement detection device, in which a conductor as shown made of a metal film or the like is disposed on an insulating substrate (not shown), and the pattern is slid over. The movable brush 102 slides in the direction of the arrow, and a pulse signal is generated by contact between the conductor and the brush. 10
3 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 control the counting of clock pulses input from the CP terminal. A clock pulse generator 105 is composed of, for example, an astable multivibrator, and generates pulses of a constant period. 106 is
The output of the AND gate is input to the CP terminal 104 mentioned above.

The first counter 104 is controlled by the signal from the brush 102 to count the clock pulses from the CP, and produces binary code pulse outputs to its output terminals "1", "2", "4", and "8". . 104
Of the outputs of , the output pulse of output terminal "4" is the second
is input to the CP terminal of the counter 108, where it is again counted in binary.

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 to the other input of this 109, a digital preset signal is input from a preset signal source 110 for photographing information, and when they are compared at 109 and match, a digital preset signal is input. 109 outputs are produced.

The output from 109 is an electro-mechanical conversion means 111
is converted into a mechanical displacement amount, and the sliding of the sliding brush is controlled and stopped. As described above, digital information corresponding to the sliding distance of the brush 102 from the starting position is obtained, and with this, for example, the aperture mechanism is controlled and the aperture value is determined.

FIG. 3 is a waveform diagram showing a timing chart for explaining the operation of the circuit of FIG. 2. In FIG. 2, when the power switch (not shown) is closed, the pulse generator 105 generates a clock pulse with a constant period as shown in FIG.
The signal is inputted to the CP terminal of the first counter 104 via , and is counted in binary at 104 . brush 102
When it slides on the pattern 101, first, a start signal is input to the clear terminal 104, and counting starts from this time. Binary code outputs are obtained sequentially from output terminals 1, 2, 4, and 8 of the 4-bit counter 104, but among these, output terminals "1" and "2" are unused, and output terminals "4" terminal is connected to the second counter. Further, the terminal of the output terminal "8" is inputted to the AND gate 106 via the inverter 107 and connected to the input terminal CP of 104 in a closed loop. Therefore, the counter 104 does not count beyond 8. FIG. 3b shows a signal from the brush which, when in contact with the pattern, produces the chattering as shown. In order to avoid this, the output of 104 only outputs the signal that occurs at terminal 4 during the period from count 4 to count 7, as shown in FIG. 3c. Also, in order to eliminate malfunctions caused by the brush sliding speed being slow compared to the period of the clock pulse and the counter counting twice or more, in this embodiment, the count is 8.
Thereafter, the clock pulse is blocked by the AND gate 106 to prevent it from being input to the counter 104. Therefore, a signal corresponding to the number of contacts between the brush and the pattern is reliably input to the CP terminal of the second counter 108. If the period of the clock pulse is selected to be sufficiently high relative to the sliding speed, an accurate output signal can be obtained as described above.

The output pulse of FIG.
8, the output is compared with the preset value as described above, and when they match, the comparator 1
The sliding brush is mechanically controlled and stopped by the output from 09.

FIG. 4 is a plan view a showing an embodiment of a comb-shaped conductor pattern constituting the mechanical displacement detection device of the present invention, and a speed characteristic diagram b showing brush sliding characteristics. In the figure, 101 is a comb-shaped conductor pattern, 102 is a sliding brush, 103 is a start position signal pattern, 112 is a common return path pattern, 1
Reference numeral 13 indicates an insulating substrate, and reference numerals 114 and 115 indicate connecting wires from the patterns. These patterns 101,1
03 and 112 are fixedly disposed on an insulating substrate 114 using a conductor piece or a method such as vapor deposition, and the sliding brush 102 slides thereon from the starting position S to the right with a constant acceleration movement as shown in FIG.

Reference numeral 103 is a start pattern placed independently at the brush sliding start position. By sliding this pattern, a start position signal is obtained, which clears the second counter as shown in Figure 2. In addition, it has the role of reducing wear on the first pattern of the comb-like pattern 101. Reference numeral 112 denotes a common return path pattern provided in parallel to the comb-like pattern 101, and connecting conductors 114 and 115 of 101 and 112 are drawn out from ends in opposite directions 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 tooth pattern, and the widths are changed in consideration of the contact time between the brush and the comb teeth corresponding to the brush speed shown in Figure b. Further, e to n in Fig. a are the stop positions of the sliding brush where the sliding brush stop drive mechanism actually stops the brush upon receiving a stop signal, and the interval between each stop position is set to be constant. On the other hand, the positions of the comb teeth in the pattern as shown in R, U, and V in the figure should be adjusted in consideration of the timing at which the brush stop signal is generated.
They are arranged so as to be corrected forward like e' to n'. This is to correct the amount of movement in accordance with the speed of the brush due to the time delay caused by the electromagnetic magnet that causes the brush to stop and other mechanical delays in the drive mechanism. In Fig. 4b, when the brush is moving at a constant acceleration, α is the acceleration from the start position where the brush actually slides and stops from the stop pulse generated by the contact between the sliding brush and the comb teeth. The distance is S', the time delay at this time is T, the distance from the start position of the stop pulse generation position is S, the time from the start to the stop pulse generation is t, and the interval between each stop position e to n is l, If the number is n, then the pulse generation position S is S=1/2αt ² (1), and the actual stopping position S′ is expressed as S′=1/2α(t+T) ² (2), which is will be equal to nl. That is, S′=nl
becomes.

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

In other words, the corrected path deviation ΔS is Δ〓S=S′−S=1/2α(2tT+T ² ) (3) If we substitute the relationship nl=1/2α(t+T) ² into equation (3) and eliminate t, we get ΔS = T√2−1/2αT ² (4). In equation (4), l is constant, so depending on n, α, and T, R, U, V......
By calculating the distance corrected by the delay, the shape of the comb-like pattern can be determined. In addition, figure b
Since the motion after m' is constant velocity, the pattern for this will be an equally spaced pattern.

FIG. 5 is a perspective view showing the sliding state of the comb-like conductor pattern 101, the common return path pattern 112, and the sliding brush 102, and both patterns are shown in FIGS.
It has been shown that by arranging the brushes as shown in Figure a, it is possible to use a sliding brush with a simple structure as shown in Figure 5a. In the case of a pattern arrangement as shown in FIG. 5B, it is necessary to use a brush having a structure as shown in FIG. 5B, and the cost will be higher than that shown in FIG.

As described above, the mechanical displacement detection device according to the present invention counts digital signals corresponding to mechanical displacement,
In order to accurately stop the mechanical displacement means at a predetermined position by forming a closed loop by matching outputs with calculated values or preset values of digital information of various types of photography, the sliding brush is adjusted in consideration of the delay in stopping response of the sliding brush. A comb-shaped pattern is set according to the speed, and the mechanical displacement obtained from this can be made highly accurate and stable.It is especially effective when applied to digital control devices such as cameras. It is a big thing.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a digital control camera to which the mechanical displacement detection position according to the present invention is applied, and FIG. 2 is an example of a counting device to which the mechanical displacement detection device according to the present invention is applied. FIG. 3 is a waveform diagram showing an example of a timing chart for explaining the operation of FIG. 2, and FIG. 4 a,
Fig. 5b is a plan view showing an embodiment of the comb-tooth-shaped conductor pattern and sliding brush constituting the mechanical displacement detection device of the present invention, and a speed characteristic diagram showing the brush sliding characteristics; FIG. 3 is a perspective view showing the arrangement of a shaped conductor pattern, a common return pattern, and a sliding brush. 101... Comb tooth-shaped conductor pattern, 102...
Sliding brush, 103...Start position conductor, 10
4...First counter, 105...Clock pulse generator, 106...AND gate, 107...Inverter, 108...Second counter, 109...
... Comparator, 110 ... Preset signal source, 111
...Electrical-mechanical converter.

Claims (1)

[Claims] 1. A start position contact, a plurality of position detection contacts arranged in a predetermined direction from the start position, and a position detection contact with a predetermined acceleration from the start position contact. In a mechanical displacement amount detection device that has a moving member that moves and converts the amount of mechanical displacement of the moving member into an electrical signal, for detecting the position within a range in which the moving member moves with acceleration. 2. A mechanical displacement detection device, characterized in that the distance between the contacts is gradually increased from the start position contact.