KR860000474Y1 - Automatic forcusing camera - Google Patents

Abstract

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Description

Auto focus camera

1 is a perspective view of a 35mm camera showing conventional adjustments and adjustments suitable for the present invention.

FIG. 2 is a graph showing waveforms of an output of an optical sensor circuit portion of the FIG. 3 circuit in response to a subject reflection flash lamp light when the distance measuring mode of the camera is operated, and the threshold level L− of the signal level detector in response to the output. Peak values of output waveforms exceeding 1, L-2, L-3 are shown.

3 is a circuit diagram of the electrical parts of the camera, and shows a mechanism that operates upon pressing the shutter release button to adjust the movement of the wiper contact operating in the distance measuring operation performed by the present invention.

FIG. 4 is a circuit diagram showing details of a preferred circuit that performs the functions indicated by most of the square portions shown in FIG.

* Explanation of symbols for main parts of the drawings

8: Flash on-off switch 9: Shutter release button

10: on-off control unit 16a: filter circuit

19a: reference voltage source 19b: comparison circuit

20, 21: capacitors 24A to 24C: signal level detector

26-1 to 26-4: Conductor piece 38: Solenoid

46: cock gear 48: release lever

58 neon lamp 82 SCR element

The present invention provides information on the distance between the subject and the camera before shooting, using the flash lamp light to enhance the subject lighting condition or not, and focuses the camera so that the subject image is automatically properly focused on the film surface. A camera using a flash lamp attached to a camera for automatically adjusting the focusing means.

When the shutter release button of the camera is pressed, the distance measuring flash is always fired at first, and when a photograph enhanced with flash light is desired, the distance measuring flash fires with the same button press and the film exposure flash fires. Conventional autofocus control techniques have something in common. The shutter opening occurs after the quick acting flash lamp reflected light measuring circuit operates the focusing system in response to the amount of flash lamp light reflected from the subject.

In many prior art systems of this type, separate flash lamps have been used for ranging and exposure flash operations, and the distance between the subject and the camera integrates the light energy received from the initial light flash, and the integrated measurement Was determined by measuring the time to reach a predetermined value.

U.S. Patent Nos. 3,681,649 (owned by Unoetal) and 4,256,995 (owned by Ishida) are initially energy-saving low-level flash lamp energy releases (first flash operation) and high levels of energy in the same flash lamp when flash light exposure is required By having the emission occur (second flash operation), distance measurement and film exposure enhancement have been made possible with one flash and with one operation of the shutter release button, and thus have a desirable commonality with the present invention.

The flash circuits described in the above patents use separate capacitors, each discharged through a flash lamp, for distance information and film exposure. In the circuit of US Pat. No. 4,256,995, a branch consisting of an emitter-collector path of a constant current regulating transistor and a cathode-anode path of an SCR element is provided for the first flash operation. Connected in parallel, which in turn is placed in series with the flash lamp. The base of the current regulating transistor is connected to a constant current generating regulating circuit which makes the transistor conductive during the first flash operation in which the SCR element remains non-conductive.

During the second flash operation, the SCR element becomes conductive to bypass the transistor. Thus, a current regulation circuit for the flash lamp is provided only during the first flash operation. The flash circuit of U. S. Patent No. 3,681, 649 provides no control of current flow during the first flash operation.

These conventional ranging systems are relatively complex, expensive, and consume a lot of battery power and have many improvements.

An object of the present invention is to provide a distance measuring system using flash light, which is more energy efficient and cheaper than in the prior art.

Light-assisted ranging systems of some prior art cameras use an infrared light source obtained by filtering visible light from a broadband light source or an infrared reflected light source obtained by using an infrared source for distance measurement from the outset. This is because infrared is believed to provide more precise distance information when visible light is removed from the measurement. US Pat. Nos. 4,221,474 and 1,886,581 describe examples of such infrared ranging systems.

According to a feature of the present invention, the measurement of the distance indicator light does not include any integration action to save the cost due to the integration circuit or to simplify the circuit included in the camera. Instead, only the maximum amplitude of the received infrared light energy profile is measured. Signal level detectors were used that were triggered by a signal generated by light, exceeding several different values representing the limits of adjacent distance zones starting in the nearest zone and then ending in the far zone. Thus, the signal generated by the light pulses reflected from the subject in the nearest distance zone activates all of the level detectors, and the signal generated by the light pulses reflected from the subject in the distance in the farthest zone is determined by all of the signal level detectors. Does not work. Thus, if there are n distance zones, only n-1 detectors are needed.

If all signal level detectors are not triggered, the focusing method is determined to focus the camera on the farthest distance zone, and to focus the camera on the distance range if the signal level detector is triggered to correspond to the closest distance zone.

U.S. Patent No. 4,240,726 refers to a device which automatically adjusts the focus according to the maximum, integral or average value of the brightness of the screen representing the signal, but the camera of the patent describes a multi-zone as described above. zone Not used in the same way as distance systems.

In addition, U. S. Patent No. 4,251, 144 describes an autofocus system using light signals reflected from a subject located in different distance zones, but such a multi-zone system operates in a completely different way than that of the present invention described above. .

According to this feature of the present invention, the focusing device includes a switch having a fixed contact, which is connected to the output terminal of the signal level detector, respectively.

The wiper comes in contact with the wiper, moving from its initial position and passing through the contact, starting from the contact connected to the signal level detector operated by the signal within the closest distance zone. The final contact to be contacted by the wiper has a permanent signal indicating the output of the triggered signal level detector and is connected to the farthest zone. Each time the film is rolled up, the wiper and camera lens move to the starting position. However, the lens is not yet in the position to take the closest photograph. The pressing of the shutter release button releases the wiper and the lens, and the wiper moves with the lens to various positions that first focus on the closest distance zone and then focus on the farthest distance zone.

Another more specific aspect of the present invention is that the signal contact used to fire the ranging flash prior to the first distance contact is located in front. This signal contact is used to discharge the capacitor in the distance flash control circuit so that the flash lamp emits energy. When the wiper reaches the first of the other contacts with a triggered level detector signal, the further movement of the wiper and lens is stopped due to the disconnection of energy to the solenoid with the latch. The clasps fall into the path of a ratchet wheel or the like connected to move with the wiper and the lens so that the lens is in a position to achieve proper focusing on the subject.

Another basic feature of the present invention is that a main ON-OFF switch is provided which is moved to the "ON" position when photographing, in order to increase the reliability of the circuit and minimize the current leakage.

The on-off switch connects a DC cell with a single-pole, double-throw switch that allows the wiper to contact the connected contacts to drive the high-voltage oscillator. High voltage oscillators generate a high voltage, which is used as a high charge voltage to rectify and charge the capacitors that operate the flash lamp.

Next, when the shutter release button is pressed, the wiper just mentioned moves to another contact point and disconnects the power to the high voltage oscillator (otherwise a noise voltage can be generated which falsely triggers the level detector).

This contact, mentioned later, is connected to the filter circuit, which generates a filtered DC voltage, which drives the distance measuring portion of the circuit.

Although many of the above features of the present invention have been described in connection with an autofocus camera, these features include that the distance measuring features of the present invention adjust the width or shutter opening of the flash lamp optical pulse according to the distance information, so that the flash lamp can take pictures. It is also useful when used to automatically provide appropriate exposure conditions in the case of daylight sources.

The above and other objects, advantages and features of the present invention will become apparent from the following description and utility model registration claims set forth in connection with the accompanying waveguide.

In FIG. 1, a normal viewfinder 4 is arranged on the front wall 2a, and the flash unit 5 is inserted next to the finder as indicated by the solid line, and is shown as a fixed position and a double-dotted line. A 35mm camera 1 is shown with a generally rectangular housing 2 movably mounted between spring-extended positions as shown. The flash unit has a window 5a through which the flash lamp light from the flash lamp 5b (FIG. 3) passes. On the front wall 2a, a flash on-off switch 8 is also arranged, and when the switch 8 is moved to the " on " position, the spring unit is extended by a spring from a position where the flash unit 5 is inserted and fixed. Will be moved to.

Further, a lens unit 3 rotatably mounted from the initial fixed position shown in FIG. 1 is disposed on the front wall 2a. When the lens unit is released for movement, the lens unit rotates in a counterclockwise direction as shown in FIG. 1, and automatically stops in a manner described below at a position where the object to be photographed or the scenery is properly focused.

On the front wall of the housing 2, a light receiving hole 6 'aligned with the light sensor is provided. The light sensor is an exposure control light sensor for automatically adjusting the speed and / or aperture of the lens to provide adequate exposure to the embedded film. An ASA film adjuster 6 "is provided to determine the speed of the film used.

Manually adjustable shutter time and stop adjustments (not shown) may be installed as provided in most 35mm cameras. The invention is adaptable, i.e., only one light receiving hole 6 or 6 'may be provided when a common light sensor is used for exposure control and distance measurement purposes. However, in such an example of the present invention, one feature of the present invention that arranges an infrared filter in front of the optical sensor that filters most of the reflected light of the flash lamp while leaving most of the infrared light is not used. Infrared provides the most accurate ranging information because proper autoexposure adjustments must be sensitive to all light reaching the optical sensor when using conventional films. Such ranging information may also be used to automatically adjust the pulse duration or lens opening of the flash lamp light used for proper film exposure in the flash lamp exposure mode of camera operation.

The film winding lever 11 is installed on the upper wall 2b of the camera housing. The lever is reciprocated after shooting to advance the film by one screen distance and prepare a shutter. In the present invention, the film winding lever 11 also moves the position of the lens unit 3 to a reference position at which the lens unit is at its closest focusing position. However, the correct focusing of the camera does not occur at that position of the lens unit.

The upper wall 2b of the camera is provided with a shutter release button 9 which can also be pressed, and when the button 9 is pressed, the low level energy emission of the flash lamp 5b for distance measurement purposes. Do this. The flash light generated by such energy release of the lamp impinges on the subject and is reflected toward the camera and enters the light receiving hole 6.

Distance measurements at that hole are made in the manner described below. In a short time before the shutter moves to the position to expose the film, the reflected flashlamp light is measured and the lens unit 3 is released from its fixed position. In that position the lens unit is driven by a spring in a direction that focuses the lens on subjects positioned at increasing distances from the camera. According to the peak amplitude of the light detected by the light sensor connected to the light receiving hole 6, the lens unit 3 is stopped at a position where the subject at any position in the distance zone can be properly focused. That is, the distance zones are sufficiently subdivided so that a subject far from the camera by any distance in the zone can satisfactorily focus on the film phenomenon. In one embodiment of the present invention, the lens unit 3 has an index mark 3c on the ring 3b of the lens unit, and four index marks 12a and 12b on the bezel 14 in front of the camera housing. 12c) may be stopped at one of four different positions coinciding with one of (12d).

These distance zone index marks "1", "2", "3", and "4" represent distance zone numbers 1, 2, 3, and 4, which are distances gradually away from the camera, respectively. If the flash on-off switch 8 is in the " on " position after the distance measurement has been performed, the flash lamp will respond to the pressing of the shutter release button 9 which caused the lamp to release flash lamp energy for distance measurement. When moving to the open position, the flashlight automatically releases energy again.

The top wall 2b of the camera housing is also provided with an on-off control 10 which, when in the "on" position, energizes the camera circuits for ranging and flash operation. The camera housing 2 also has a rear door 2c attached to the hinge so as to be moved between the housing closing position and the housing opening position, which is a position covering the film as in a conventional 35mm camera.

As already mentioned at the beginning of this specification, the distance measurement operation used in the present invention is performed by detecting the peak value of the flash lamp light profile detected by the sensor connected to the light receiving hole. The integration differs from that used in the prior art which normally operates. 2, waveforms C1, C2, C3, of the output of the optical sensor circuit for flash lamp light pulse profiles reflected from a subject located in distance zone numbers 1, 2, 3 and 4, respectively, indicating distances gradually falling from the camera. A graph showing C4 versus four flash voltages or currents versus time is shown. These distance zones are shown as their highest distance positions are 6 feet, 9 feet, 15 feet, and infinity, respectively. Each distance zone number so that the lens unit index marks 3c coincide with the outer marks 12a, 12b, 12c, and 12d, respectively, to focus the subjects in the four distance zones on the film plane. An optical sensor output flashlamp profile having peak values representing the distance between the subject and the camera to which the flashlamp light is reflected in 1, 2, 3 and 4 performs positioning of the lens unit 3.

Although the lens unit 3 may increase the number of distance zones that can be adjusted, it has been found that good image sharpness can be obtained even with four distance zones.

3 shows various features of the present invention, such as some networks, functional blocks and mechanical devices. As shown, the battery 15 is provided with the negative pole grounded and the positive pole connected to an on-off switch 10 'operated by the on-off control 10 of the camera housing. It is. When the adjuster 10 is moved to the " on " position, the positive electrode of the cell 15 is connected to a filter circuit 16a including a capacitor 16a 'and a resistor 16a. At the connection between 16a '' and capacitor 16a, a vf (filtered DC voltage) terminal is arranged, which terminal supplies energy to most of the circuits shown in FIG. 3 except for flash lamp control circuits. By the short circuit of the switch 10 ', the voltage of the battery is supplied to the wiper 9a' of the switch 9 'operated by the shutter release button 9. The wiper 9a' is initially operated. The fixed contact is connected to the oscillator to energize the high voltage generator 17. The output of the oscillator 17 is connected to the negative bus via the rectifier 18. It is connected to B, and its bus extends to various branch circuits described below, one of which is connected to the output bus B. 5b 'and a flash lamp 5b having a terminal 5b ". A relatively small capacitor 20 is connected between the flash lamp terminal 5b' and ground. The non-grounded terminal is charged with a negative voltage to ground via rectifier 18. The trigger capacitor 21 is also charged via rectifier 18. Capacitors 20 and 21 are referenced by reference numeral ( 19B), which is described below as an overall distance flash control circuit, which emits low-level energy to the flash lamp at an initial time interval after operation of the shutter release button 9. Branch circuit between bus B and ground Some of them include a relatively large capacitor 20 'and a trigger capacitor 21 in the flash exposure control circuit 19A, the capacitors of which a high level flash energizes the flash lamp 5b to expose the film exposure flash. It is required to generate light The flash lamp exposure control circuit 19A will be described later in this specification.As soon as these capacitors are properly charged, the operation of the high voltage oscillator 17 is entirely described by a circuit described below with reference numeral 19. It ends. The circuit 19 includes a reference voltage source 19a and a comparison circuit 19b, the comparison circuit having one input thereof connected to the reference voltage source 19a, and the other input portion having a trigger capacitor 21 and a resistor ( 72) is connected to the connection.

Resistor 72 is connected to negative bus B. The output of the comparison circuit 19b is connected to the base of the regulating transistor 19c, the emitter of the transistor is grounded, and its collector is connected to one of the terminals of the high voltage oscillator l7 via the conductor W2. . Normally, transistor 19c is non-conductive so that high voltage oscillator 17 is in operating condition. However, when the comparison circuit 19b indicates that the trigger capacitor 21 is properly charged, the comparison circuit 19b supplies a voltage to the transistor 19c and the transistor becomes conductive to stop the operation of the oscillator 17. Quit.

When the shutter release button 9 is pressed, the wiper 9a 'comes into contact with the fixed contact 9c' connected to the V + terminal, which energizes only the solenoid regulating circuit to be described later.

As described above, the flash lamp 5b upon single pressing of the shutter release button 9 initially releases energy to a relatively low degree for distance measurement purposes, and then flashes to the "on" position when the flash operation is required. The movement of the -off switch releases energy to a very high degree, which enhances film exposure with this high energy flash light. When the shutter release button 9 is released, the wiper 9a 'returns to its contact position 9b', thereby disconnecting energy to the distance measuring circuits to be described later.

As described above, the lens unit 3 is also rotated and fixed at the position shown in FIG. 3 when the film winding operation is completed by operating the film winding lever 11 to fix the shutter. At that position the lens unit is in a position where the subject image is first focused on the film surface for the subject in the closest distance zone number 1 when he is released for forward movement. A mechanical device for securing and driving the lens unit 3 and then stopping it at a suitable distance zone position is shown in FIG. The device includes a spring loaded drive gear 44, which gear rotates clockwise as shown in FIG. 3 by spring force. The gear is controlled by the cocking gear 46 to rotate by the spring force. The gear 46 has a recess that provides a shoulder 46a, which is supported by the latch arm 48a of the release lever 48 to release the gear. The button 9 is held in a fixed position until pressed. When this release button is pressed, the arm 48b of the lever 48 is pushed upward as shown in FIG. 3 to rotate the release lever counterclockwise, and thus the spring applied to the string load driving gear 44. Unlocking the gear to rotate the cocking gear 46 under force. The spring 50 normally pushes the release lever 48 in a direction such that its upper arm 48c contacts the pin 40c on the lever 40, thereby pawling the lever 40 ( 40a is pushed out of the moving path of one of the teeth 28b 'of the wiper and cam gear 28a. The drive gear 44 meshes with a gear (not shown) forming part of the wiper and the cam gear 28 so that the drive gear 44 can rotate freely and the shutter release button 9 is pressed and the tooth stops. When the gear 40a is not engaged with one of the cam gears 28a and the teeth 28b 'of the wiper, the drive gear 44 counterclocks the gears forming part of the gear wiper and the cam gear 28. Rotate in the direction.

The spring 42 pushes the lever 40 in the direction in which the detent 40a engages one of the teeth 28b ', but such an operation is initially carried out by the arm 48c of the release lever 48. Is prevented. When the shutter release button 9 is initially pressed and the release lever 48 is rotated to release the drive gear 44 as described above, the cocking gear 46, the wiper and the cam gear 28a and the lens The unit 3 is driven.

A solenoid 38 is provided which is energized during the initial time interval after the push of the pushbutton 9. When the solenoid 38 is energized, the lever 40 is energized by the energized solenoid so that the detent 40a of the lever moves the teeth 28b 'of the wiper and cam gear 28a. The position away from is retained.

The detent 40a can move to a position where the wiper and cam gear 28a are fixed so that the gear does not continue to rotate when the energization is interrupted by the solenoid 38. A circuit for energizing disconnection of solenoid 38 will be described. The circuit is subjected to the light reflected from the subject when the distance flash lamp pulse is generated by the flash lamp 5b during the initial interval after the shutter release button 9 is operated.

As described above, in the most preferred embodiment of the present invention, the subject reflection flash lamp light L ₁ enters into the light receiving hole 6 on the front wall 2a of the camera and passes through the filter 22 to the optical sensor circuit 23. It hits the light sensor part.

The filter 22 filters most of the light wavelengths except the infrared wavelengths which make more precise distance measurement. The optical sensor generates a voltage, or current, in the optical sensor circuit in proportion to the instantaneous fluctuations in the light energy striking it.

Dotted line L ₁ of FIG. 3 shows the modification which remove | eliminated the infrared filter 22 so that incident light may hit an optical sensor directly. The filter 22 generates a signal for which the optical sensor is used for distance measurement purposes, and operates an electronic internal control device 25 for adjusting the shutter speed or lens opening according to the amount of ambient light received by the optical sensor. It is removed only when performing a heavy function.

With or without the electronic exposure device 25, the distance measurement operation is performed by a number of signal level detectors 24A, 24B and 24C, where n-1 such signal level detectors are provided (n is the distance Number of distance zones provided for the measurement operation). As an example of its operation, four distance zones are provided that require only three signal level detectors 24A- 24C. Exemplary circuits for the signal level detector are shown in FIG. 4 and will be described later. The signal level detectors 24A-24C are each triggered in an active state by signals exceeding one progressively decreasing levels of the signals generated in the optical sensor circuit 23. Thus, the signal level detector 24A is made to trigger when it exceeds the level L1 representing the maximum object distance of 6 feet in the relatively large flash light pulse profile C1 of FIG. Similarly, signal level detectors 24B and 24C are each made to be triggered by peak flash lamp light profile signals exceeding signal levels L2 and L3 representing maximum object distances of 9 and 15 feet.

None of the signal level detectors operate for the flash lamp light pulse profile C4 whose peak value has not reached the trigger level of the signal level detector 24C. Thus, the number of activated signal level detectors determines in what distance zone the subject distance is. Because of the particular circuit shown in FIG. 3, the activated signal level detectors generate a positive voltage at their output terminals 24a ', 24b' or 24c ', while the inactive signal level detectors It generates zero ground voltage. The outputs of the signal level detectors 24A, 24B and 24C are connected to the conductor pieces 26-1, 26-2 and 26-3 of the switch 26, respectively. The conductor pieces may be conductive attachments on the stationary insulating disk 27, through which the wiper contacts 26 'of the cam gear 28a and the wiper forming part of the rotatable instrument assembly described below pass. The wiper contact 26 'first comes into contact with the conductor piece 26-0 which, when released from the fixed position, moves counterclockwise to trigger the distance flash as shown in FIG. Then, the wiper contact 26 'is in continuous contact with the conductor surfaces 26-1, 26-2, 26-3, 26-4 if the wiper is adapted to rotate over its entire distance. do.

The final conductor piece 26-4 is connected to the vf terminal through a resistor 28. The wiper contact 26 'is connected to the cathode of the rectifier 32 by a conductor 31, and the anode of the rectifier is grounded.

The constant voltage on the wiper contact 26 'is connected to the base of the normally nonconductive NPN transistor 33 to allow electricity to pass through the transistor. The emitter of transistor 33 is grounded and the collector is connected to the V + terminal through a resistor 34. The collector of the transistor 33 is connected to the base of the transistor such that the NPN transistor 36 is in the initial energized state when the shutter release button 9 is pressed. Transistor 36 has a grounded emitter and a collector connected to the V + terminal through a coil of solenoid 38. The solenoid is energized when electricity flows through the transistor 36.

When the wiper and cam gear 28a is rotated to the spring load drive gear 44 at the time of initial pressing of the shutter release button 9, the wiper contact 26 'attached thereto is initially held by the contact piece 26-. It is moved forward in the direction of contact with 0). The contact surface is connected to the trigger capacitor 21 by the conductor 40 and the conductor W1 to discharge the capacitor through the wiper contact 26 '. The grounded rectifier 32 is oriented to pass negative voltage to ground and to the primary winding of the trigger transformer T1, the transformer secondary winding being connected to the trigger terminal 5b '' of the flash lamp 5b. . The capacitor 20 discharges through the flash lamp 5b to generate a light pulse of a relatively low level. The light pulse is reflected by the subject and enters the light receiving hole 6.

After the wiper contact 26 'contacts the first conductor piece 26-0, the contact continues to move counterclockwise such that it contacts 26-1. Normally, transistor 36, which is an NPN transistor, is in an energized state with its base connected to the V + voltage terminal through a resistor 34. When the base of transistor 36 is grounded, the transistor becomes nonconductive to break the energization to solenoid 38. Thus, the spring 42 moves the lever 40 and its fixed tooth detent 40a moves into the movement path of one of the teeth 28b 'of the wiper and cam gear 28a to stop the rotation of the gear. Pull into position.

The base of the transistor 36 is grounded when the transistor 33 is energized. Such phases only occur when the wiper contact 26 'contacts 26-1, 26-2, 26-3 or 26-4 in a positive voltage state. When the subject is in the closest distance zone, the signal level detector 24A is triggered with its output being positive, causing the contact piece 26-1 to be positive so that the wiper contact 26 'is contacted. When the piece is reached, the movement of the wiper contact is stopped. However, when the subject is in a different distance zone, the wiper contact 26 'has a positive voltage until it reaches a contact piece connected to the triggered signal level detector corresponding to each distance zone. Can't touch If neither of the signal level detectors is triggered, the wiper contact 26 'is stopped at a contact 26-4 connected to the vf terminal via a resistor 28, so that the solenoid 38 is wiper contact 26'. When it reaches this contact piece 26-4, energy supply is cut off. Such a position indicates that the subject is located in the farthest zone number four.

Up to now, the method in which the lens unit 3 is moved to a position for focusing the object on the film surface has been described. After the unfixed lens unit 3 is rotated to this position within a few seconds-this rotation takes only a few seconds-the timing of the camera unit is released by releasing the shutter that caused the lens unit to be moved to the appropriate subject focusing position. The button is arranged to achieve operation of the shutter to a position that exposes the film to ambient light or flash lamp light conditions for imaging.

When the film winding lever 11 is actuated, the shutter is ready, and the cocking gear 46 is rotated to the position where the latch arm 48a falls once again into the recess of the cocking gear so as to engage the shoulder 46a. . Next, the release lever 48 has a mechanism whose arm 48 ° moves the solenoid lever 40 off the fixed tooth detent 40a out of the path of movement of the teeth 28b 'of the wiper and cam gear 28a. Will be in a position that will swing to a position that will cause the new distance measurement operation to begin.

As another application of the present invention, the wiper position may be used to adjust the flash duration or lens aperture during flash exposure operation of the camera. When only the flash light of the subject is used, the flash exposure operation of the camera usually requires adjustment of the lens aperture for proper exposure. Accordingly, FIG. 3 shows the flash duration connected with a dotted line on the side of the wiper and camgear 28a to show the connection of the wiper and camgear to a mechanism that adjusts one of two parameters, the flash duration and the lens diameter. The time and lens diameter adjusting device 51 is shown.

4 shows a preferred circuit for performing most of the functions of the quadrangles shown in FIG. Thus, the photosensor device 23 is shown as including a phototransistor 23b having an emitter connected to ground via a variable resistor 23b and a collector connected to a + vf DC power supply. The junction between the resistor 23b and the emitter of the phototransistor 23a is connected via a capacitor 23c, which filters the effects of ambient light conditions. The capacitor 23c is connected to ground via a resistor 23d, and the non-grounded end of the resistor is input 52a of the op amp comparator 52 of each of the signal level detector circuits 24A, 24B and 24C. Is connected to. Since those signal level detector circuits are identical except for the particular input signal level that each is adjusted to trigger, only one of the signal level detectors is described. The other detector circuits actually have the same network.

Thus, each of the operational amplifier comparator circuits 52 of the signal level detector circuits 24A, 24B, and 24C has an inverting (-) input terminal 52a connected to an output of the sensor circuit capacitor 23C, and a resistor ( 54, and a non-inverting (+) input terminal 52b connected to a + vf DC power source via a resistor 56. Resistor 54 and 56 are provided for the flash lamp optical signal profile in which the voltage on each non-inverting input terminal 52b, which forms a different voltage division circuit at each of these signal level detectors, is supplied to the inverting input terminal 52a. Same as the peak value.

The output terminal 52c of each operational amplifier comparator circuit 52 is connected by the resistor 57 to the vf terminal of the DC power supply. When the magnitude of the voltage on the inverting input terminal 52a of a certain comparator circuit 52 exceeds the magnitude of the voltage on the non-inverting input terminal 52b, the voltage at the output 52c of the comparator circuit 52 is It is switched from its initial positive voltage to ground to drive the flip-flop circuit 53. The set (SET) input terminal 53a of the circuit is connected to the output 52c of the comparator circuit 52. The flip-flop circuit 53 connected to each of the comparator circuits 52 has a reset input portion 53b that is reset when each distance measuring flash operation is completed.

This reset circuit will be described later. When the flip-flop circuit 53 is in its set state, its output portion 53c becomes positive (+), and when the flip-flop circuit is in the reset state, its output portion 53c is at ground potential. (After the wiper 26 'is released from the starting position of the lens unit movement due to the pressing of the shutter release button 9, the specific contact piece in response to the constant output to terminate the movement of the lens unit 3). The method of stopping is already explained).

In the commercially available circuit form, the flip-flop circuit 53 was barely operated because of the better battery voltage when the battery 15 was 3 volts. To avoid this problem, a large useful DC voltage, relatively low but higher than 3 volts, was obtained from the high voltage generator 17. For this purpose, the DC supply circuit 57 was formed by a rectifier 57a connected between the collector 59c of the high voltage oscillator transistor 59 and one terminal of the capacitor 57b (the other terminal is grounded). . The point vp between the capacitor 57b and the rectifier 57a provides a constant voltage suitable for energizing the flip-flop circuits 53 when the shutter release button 9 is pressed. Capacitor 57b maintains the DC voltage for a time interval during which the high voltage oscillator is not operating.

The energized high voltage oscillator 17 initially at which the power on-off switch 10 'is in its "on" position may be any well known oscillator circuit. As shown, the oscillator has an output transformer T2 and a high frequency high voltage AC voltage is induced in the secondary winding T2a of the transformer.

One end of the secondary winding T2a is connected to the rectifier 18 connected to the bus B, and the other end of the secondary winding T2a is connected to the collector of the transistor 19c by the conductor W2. The transistor is not normally energized but is energized when the trigger capacitor 21 is charged to a desired level. The oscillator 17 cannot operate unless its secondary winding T2a is grounded through the transistor 19.

The circuit l9 includes a comparator circuit 19b which compares the voltage of the reference voltage source 19a with the voltage at which the trigger capacitor 21 is charged (preferably 300 volts in the illustrated circuit). In FIG. 4, the conductor W1 extending from the trigger capacitor 21 is shown connected to the neon lamp 58 through the resistor 56 and grounded through the capacitor 60. Neon lamp 58 may provide a voltage drop of 240 volts, for example. The voltage at the side of the neon tube adjacent to the capacitor 60 is connected to the inverting input terminal 62a of the operational amplifier comparator circuit 62.

The non-inverting input terminal 62b of the circuit 62 is connected to the anode of the rectifier 19a serving as a reference 0.7 volt power source. The cathode of the rectifier 19a is grounded. As shown in FIG. 4, the positive pole of the rectifier 19a is connected via the resistor 66 to the output 62c of the comparator circuit 62 and through the resistor 68 to the + vf terminal of the DC power supply. It is. A resistor 70 is connected between the output 62C of the comparator circuit 62 and the base of the transistor 19C.

Normally, the output portion of the comparator circuit 62 is at ground potential because the voltage at the non-inverting input portion 62b of the comparator circuit is higher than the reference 0.7 volt supplied with the non-inverting input portion 62b.

When the negative voltage on the capacitor 21 rises to about -330 volts, the various voltage drops appearing in the circuit including the lead W1, the resistor 56, the neon lamp 58 and the resistor 64, The voltage on 62a) drops below +0.7 volts so that the output of the comparator circuit switches to a constant voltage. This constant voltage is connected to the base of the transistor 19c via a resistor 70 so that the transistor is energized. This grounds the base of the oscillator transistor 59 and prevents the oscillator from operating. In this way, the voltage to the resistor 21 and other capacitors of the flash lamp control circuits 19A and 19B is determined to a desired value.

When trigger capacitor 21 is charged, the voltage at the bottom terminal of neon lamp 58 is a low negative voltage, and capacitor 60 connected between that terminal and ground is charged to that voltage. This negative voltage is connected to the reset inputs of each flip-flop circuit 53 by the conductor W4 and keeps it in the reset state.

When the trigger capacitor 21 discharges to start the ranging flash operation in the manner described below, the voltage on the conductor W1 extending from this negatively charged capacitor changes rapidly toward the ground potential (+). The effect of this positively changing voltage connected between neon lamp 58 and ground and somewhat delayed by capacitor 60 connected to inputs 62b of flip-flop circuit 53 by conductor W4 is therefore This eliminates the reset voltage from the circuit, allowing the flip-flop circuits to be set.

The purpose of the short delay provided by the capacitor 60 is to prevent flip-flop circuits from being set by the noise signals generated in the circuit when the capacitors discharge to energize the flash lamp 5b. .

The distance flash control circuit 19B of FIG. 4 will be described. As already mentioned, a relatively small capacitor 20 (e.g. a capacitor of about 10 microfarads) is connected between the flash lamp terminals 5b 'and 5b' '. The trigger capacitor 21 of this circuit is connected between the ungrounded end of the primary winding T1 'of the trigger transformer T1 and a resistor 72 extending to the negative bus B. The trigger capacitor 21 is discharged when the wiper 26 'contacts the first conductor piece 26-0 of the switch 26 (FIG. 3). When the trigger pulse is generated by the discharge of the capacitor 21 through the primary winding T1 ', the capacitor 20 discharges through the flash lamp and is large enough for the distance measuring purpose (it is usually inadequate for the exposure purpose to save battery output). Fires an optical flash. However, for the purpose of exposure, the flash lamp 5b is energized by the exposure flash control circuit 19A described later.

The circuit 19A includes a large capacitor 20 '(e.g. 180 microfarads) connected between the negative bus B and the parallel circuit, which includes an SCR element 82 connected to ground. Branch and another branch having a rectifier 77 in series with a resistor 78 and a flash on-off switch 8 '.

The switch 8 'is also grounded through the rectifier 80.

Rectifiers 77 and 80 are directed such that capacitor 20 'is charged with a negative voltage on bus B that is less than the voltage drop that occurs across resistor 78 and rectifiers 77 and 80. Is placed.

The SCR element 82 is arranged in a direction such that the capacitor 20 'is discharged through the anode-cathode circuit of the SCR element 82 when he is triggered by a short circuit of the conventional synchronous switch 76. The switch 76 is shorted by the camera when the shutter is moved to the lens open position. The control terminal 82a of the SCR element is shown connected to the connection between the rectifier 80 and the flash on-off switch 8 '. Thus, it is evident that the SCR element 82 cannot be fired when the flash on-off switch is in the "off" position. Rectifiers 77 and 80 are arranged in a direction to prevent discharge of the capacitor 20 '.

The trigger capacitor 20 'of the flash exposure control circuit 19A is connected between the anode of the rectifier 74 and the ungrounded end of the primary winding T1' of the trigger transformer T1 '. When the synchronous switch 76 is shorted because the flash on-off switch is in the "on" position, the trigger capacitor 21 'is the primary winding T1', the synchronous switch 76, on-off of the trigger transformer T1. Discharge through a circuit comprising a switch 8 ′ and a grounded rectifier 80. A ringing voltage is generated by the sudden discharge of the trigger capacitor 21 'connected to the regulating terminal 82a of the SCR element 82, so that this SCR element is fired and the capacitor 20' is connected to the SCR element 82. And the flash lamp terminal 5b can generate an optical flash. It should be noted that the flash lamp energizing circuit and the distance measuring energizing circuit are not connected to the cell at the same time, so that sufficient power can be obtained from the cell during delicate ranging operation.

In addition, if the capacitor is properly charged before the shutter release button is pressed, the battery power leakage is further reduced by using a circuit that disables the high voltage oscillator. In addition, by disconnecting the energy to the high voltage oscillator during the distance measuring operation, the high voltage oscillator eliminates adverse effects on the correct operation of the distance measuring circuit.

It is evident that the present invention is a highly reliable and relatively inexpensive distance measurement circuit that is particularly useful for auto focus or / and auto flash exposure adjustment cameras.

The circuit is also designed to minimize cell leakage.

It is to be understood that the present invention can be modified as many as possible in the best form without departing from the broad scope of the present invention.

Claims (11)

A flash circuit providing a distance measuring optical flash according to the initial operation of the shutter release device before the shutter is opened, an optical sensing circuit forming a distance indicating signal from the light reflected from the subject, and a lens disposed at one end of the focusing distance And a lens return and refocusing driving device for moving toward the other end, and an adjusting device responsive to the distance indicating signal to stop the refocusing movement of positioning the lens in response to the distance indicated by the signal. In the adjustment camera, the light sensing circuit 23 uses a single light sensing element that detects the reflected light and provides an electrical sensing signal corresponding to the instantaneous amplitude of the reflected light, and the control device is adapted to the gradually changing subject distance. Adjacent zones have corresponding different threshold levels and are sensitively connected to the sensing element. A plurality of signal level detectors operable up to a latch state indicating that the sense signal has exceeded the threshold level of each detector, the signal level detectors 24a'-24c 'of The scanning device coupled to operate synchronously with the movement of the lens 3 to detect the output states of the detectors, and when the scanning device detects a detector output state representing a subject distance corresponding to an instantaneous lens focal value. An autofocus camera comprising a drive stop device (40a, 28a, 33, 36, 38) for stopping movement. The auxiliary flash circuit (8) according to claim 1, wherein the shutter is opened to expose the film and the lens aperture adjusting device (51) provides a second illumination flash when the lens aperture adjusting device (51) adjusts the amount of illumination to the film according to the distance detection of the scanning device. 26-0, 20 ', 21'). The camera according to claim 1, further comprising an electronic exposure control device (25) provided with an electronic exposure control device (25) for adjusting the amount of light on the film according to the amount of ambient light sensed by the single light sensing element after receiving the distance indicating reflective flash light. . 2. The camera according to claim 1, wherein the flash circuit comprises an auxiliary flash circuit (8, 26-0, 20 ', 21) for providing a second light flash for illuminating a subject when the shutter release device opens the shutter. . 2. The flash circuit according to claim 1, wherein the flash circuit includes an auxiliary flash circuit (8, 26-0, 20 ', 21) for providing a second light flash for illuminating a subject when the shutter release device opens the shutter. The flash circuit uses the same flash lamp 5b to provide the distance measuring flash and the second lighting flash, which generates both visible and infrared light, and passes most visible light without passing most of it. The camera having an infrared filter (22) passing through infrared rays in an optical path to the sensing element. 2. The lens return and drive device (46, 48, 44, 18) according to claim 1, wherein the lens returning and driving device (46, 48, 44, 18) places the lens (3) at an initial position focusing on the nearest subject and then at a subject distance within a distant distance zone. Driving to the focused position, the scanning device is synchronously driven to continuously detect the signal level detectors 24a'- 24c 'in order of increasing detector sensitivity, and the drive stops 38, 40a, 28b, 44) is operable to stop the movement of the lens when it is detected by the scanning device that the first detector is in a triggered state. 7. The injection device according to claim 6, wherein the injection device comprises a switch (26) consisting of one movable contact and a plurality of stationary contacts (26-0 ... 26-4), said movable contact being from an initial starting position. When released, they move in a given direction to engage sequentially with the stationary contacts, wherein each stationary contact is connected to an output of one of the detectors, the stationary contacts being the movable contacts in order of increasing detector sensitivity. And a camera shutter cocking device is connected to return the movable contact to the initial starting position, and the shutter release device is activated to move the movable contact in the given direction. The camera to exercise. 8. The camera of claim 7, wherein the movable contact is adapted to move with the lens. The apparatus of claim 8, further comprising: a spring driving device for driving the lens and the movable contact; and the lens against the force of the spring driving device when the lens and the movable contact return to the initial position by the shutter cocking device. Mechanical latches 46 and 48a are provided to hold the movable contacts, and the latch is released during operation of the shutter release device to allow the spring drive device to move the lens and switch away from their initial position. The camera to be operated in a closed state. 10. The solenoid operated according to claim 9, wherein the drive stop device is biased by the spring in the extended position and when the solenoid 38 is excited, the tooth stop 40a is held in the retracted position against the force of the spring. A spring biased lever 40, the solenoid 38 is excited and thereafter to release the solenoid 38 when the movable contact 28a engages a fixed contact connected to the detector in the latched state. Solenoid control circuits 9a ', 9c', 16, 28a, 33, 36 in response to initial operation of the shutter release device and teeth which can engage the tooth detent when the tooth detent is in the extended position ( 28b '), including a tooth element 28a paired to move with the lens and movable contact, wherein the solenoid retracts the tooth detent by the initial actuation of the shutter release device. The camera is here to. 8. The terminal according to claim 7, wherein there is a last fixed contact (26-4) in addition to the fixed contact connected to the signal level detector attached next to the farthest zone, the last fixed contact for the signal generated by the output of the fixed signal level detector. Said camera being connected to a replicating signal source, where n is the number of given distance zones, where there are n-1 signal level detectors and the farthest zone is infinite.