JP2001318412A - Camera and moving member detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera constituted so that at least an image plane is prevented from being exposed even in the case of using an infrared photosensor. SOLUTION: In the camera detecting the amount of film fed by detecting the existence of the perforation of the film with a light emitting element emitting infrared light and a light receiving element receiving the infrared light, the existence of the perforation of the film is detected by making the light emitting element intermittently emit the light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the presence or absence of film perforation by an infrared photo sensor,
The present invention relates to a camera for detecting a film feeding amount.

[0002] The present invention also relates to a moving member detecting device for detecting a position of a moving member performing a predetermined movement.

[0003]

2. Description of the Related Art When a film is wound up one frame, if the amount of film winding is not accurately detected, frames shot may overlap. For this purpose, a sprocket that engages with the perforation was provided before, and the amount of hoisting was detected by the amount of rotation of the sprocket. However, sprockets are large in size, which tends to hinder miniaturization of cameras, and in recent years, electronic components have become inexpensive, and cameras using infrared photosensors have been increasing. The infrared photosensor includes a light-emitting element and a light-receiving element, and is configured to emit infrared light from the light-emitting element for the perforation of the film and receive the reflected infrared light by the light-receiving element. The presence or absence of perforations is detected based on the amount of reflected light, and the number of detected perforations is counted.

A camera is provided with a large number of moving members such as a lens barrel, and these moving members have an initial position, a photographing position, and an intermediate position therebetween. These three positions are detected using detection means including sensors and switches.

[0005]

In a conventional camera of the type in which the amount of film winding is detected by detecting the presence or absence of film perforation with an infrared photosensor, infrared light is emitted from a light emitting element during film winding. It emits light continuously. For this reason, when an infrared film is used, there has been a problem that the screen is exposed to infrared light.

The present invention has been made in view of such a problem, and a first object of the present invention is to propose a camera in which at least the inside of a screen is not exposed even when an infrared photosensor is used. .

Further, in order to detect three positions of a moving member such as a lens barrel, conventionally, it is necessary to use two detecting means including sensors, switches, and the like, and the configuration is complicated and the cost is increased. .

The present invention has been made in view of such a problem, and it is a second object of the present invention to propose a moving member detecting device capable of detecting three positions of a moving member with one detecting means.

[0009]

The first object is achieved by any of the following means.

In a camera for detecting the presence or absence of film perforation by a light emitting element that emits infrared light and a light receiving element that receives infrared light to detect the amount of film being fed, the light emitting element emits light intermittently. A camera that detects the presence or absence of film perforation.

The second object is achieved by any of the following means. A moving member for performing a predetermined movement, having at least three types of reflecting surfaces having different reflectances, a reflecting member for moving the reflecting surface in conjunction with movement of the moving member, a light emitting element and a light receiving element; Light detecting means for reflecting the light emitted from the light emitting element on the reflecting surface and receiving the light with the light receiving element, based on the amount of light received by the light detecting means. A moving member detection device for detecting.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] An embodiment of a camera according to the present invention which achieves a first object will be described with reference to the drawings.

First, the difference between the prior art and the present invention will be described with reference to FIG. In the prior art, as described above, while the film is being wound, infrared light is continuously emitted from the light emitting element with respect to perforation, and the reflected infrared light is received by the light receiving element. In this case, assuming that the surface of the pressure plate located on the back side of the film is mirror-finished to increase the reflectance, the amount of infrared light reflected by the pressure plate after passing through the perforation increases, and during the perforation, In this case, since the light is reflected on the surface of the film, the amount of reflected infrared light is small. Therefore, the amount of reflected light received by the light receiving element has a waveform as shown in FIG. In the figure, the filled portion is the light receiving portion. In the case of 135 film, one frame has eight perforations. Therefore, if eight peaks are detected, it is understood that one frame of the film has been wound.

On the other hand, in the present invention, the infrared light is intermittently emitted from the light emitting element with respect to perforation while the film is being wound, and the reflected infrared light is received by the light receiving element. Thus, the amount of reflected light received by the light receiving element has a waveform as shown in FIG. Since the flashing cycle of the infrared light by the light emitting element is formed to be very short, a plurality of different reflected light amounts occur in one mountain.
Therefore, although discontinuous, waveforms of peaks and valleys as shown in FIG. 1B can be obtained.

The blinking cycle of the infrared light is shorter than the cycle of detecting the presence of perforation when a new battery is loaded in the camera and the film winding speed is fastest in a high temperature state. 1 / of the period to detect the presence of perforation
It is desirable that the period be 8 or less.

In order to detect one perforation, in other words, to detect the mountain shape shown in FIG. 1B, it is necessary to detect the amount of reflected light four times. However, when perforations are read at a 1/4 cycle, it is difficult to accurately detect each perforation if variations occur due to temperature or the like in the film winding or the light receiving element. For this reason, if reading is performed at a period of 1/8 or less, perforation can be reliably detected.

The camera is provided with a microcomputer which photoelectrically converts infrared light received by the light receiving element, detects the signal as a signal, and controls film feeding. Since the lighting time of the infrared light is very short, if the microcomputer detects the timing between the timing of turning on the light emitting element and the timing of turning off the light emitting element, and the timing close to the timing of turning off the light emitting element, it is stable. The obtained signal is obtained.

Next, the present invention will be described in detail with reference to the flowchart of FIG. When the exposure of the film is completed by opening and closing the shutter, the motor is rotated forward (10
1) Wind up the film. Then, after waiting for a prescribed time, for example, a time of 250 μs (102), the photo sensor is turned on, the light emitting element emits infrared light, and the reflected light is received by the light receiving element (103). A / D conversion for quantizing and encoding this is performed (104). Then, the photo sensor is turned off to stop light emission of the light emitting element (10).
5). During this time, the time during which the photo sensor is on is 100 μs, for example.

Subsequently, the magnitude of the previously obtained signal is compared with that of the previously obtained signal, and a change in the magnitude of the obtained signal is observed (10).
6). That is, if the A / D-converted signal increases from the minimum value to the maximum value and decreases to the minimum value, one perforation has been detected. In this way, it is determined whether one perforation has been detected (1.
07). When one perforation has not been detected (N of 107), the lighting of the photo sensor is repeated after a specified time. When one perforation can be detected (Y of 107), detection is further continued, and when eight perforations are detected (Y of 108),
Since the film winding of one frame is completed, the motor is braked (109) and the motor is stopped (11).
0). When eight perforations have not been detected (N of 108), the lighting of the photo sensor is repeated after a specified time.

In the above description, the surface of the pressure plate located on the back surface of the film is mirror-finished to increase the reflectance. On the contrary, the pressure plate is roughened to reduce the reflectance. Is also good. As a result, the amount of light reflected after passing through the perforations decreases, and the amount of light reflected during perforations increases. Therefore, the position of the perforation is the position of the valley in FIG. 1. However, even in this case, the present invention can be implemented in the above-described embodiment, and the present invention includes both.

In the above description, the film is wound up. However, the present invention can be applied to a film rewinding.

[Second Embodiment] An embodiment of a moving member detecting apparatus according to the present invention which achieves a second object will be described with reference to the drawings.

The camera is provided with a number of members, such as a lens barrel, which are moved by a motor or the like. The lens barrel is collapsed when not photographing, and is extended when photographing. When the retracted position is referred to as an initial position, and the extended and photographable position is referred to as a photographing position, at the time of photographing, the lens barrel at the initial position is extended to a photographing position by a motor to perform photographing, and photographing is performed. Upon completion, the motor is reversed and the lens barrel is retracted to the initial position.

When controlling the motor for driving the lens barrel as described above, it is necessary to detect whether or not the lens barrel is at the initial position, and determine whether or not the lens barrel is at the photographing position. Need to detect. Further, since it is expected that the lens barrel stops at an intermediate position between the initial position and the photographing position due to battery exhaustion or the like, it is also necessary to detect that the lens barrel is at this intermediate position. is there.

In order to detect these three positions,
Conventionally, two switches and sensors were required. This is shown in FIG. In this figure, switch SW1 and switch S
With W2, three positions are detected. But,
Providing two switches and sensors complicates the configuration and increases the cost.

An embodiment which solves such a problem will be described with reference to FIGS. FIG. 4 is an explanatory diagram for moving the lens barrel.

In FIG. 4, reference numeral 11 denotes a lens barrel which is driven by a motor (not shown) to rotate. A lens barrel 12 holding a photographing lens L is helicoidally screwed into the lens barrel 11. For example, when the lens barrel 11 rotates clockwise, the lens barrel 12 is extended, and the lens barrel 11 is moved. When rotated counterclockwise, the lens barrel 12 is retracted. A gear 11 a is formed at the rear of the lens barrel 11, and the gear 13
meshes with a. Therefore, when the lens barrel 11 rotates, the reflection plate 13 also rotates.

The reflector 13 has three regions having different reflectivities. The first region 13b has a reflectivity of approximately 100%, the second region 13c has a reflectivity of 40 to 60%, and the third region 13d has a reflectivity of approximately 0%. . The light emitted from the photoreflector 14 serving as the light detecting means is reflected on the reflection plate 13, and the reflected light is received by the photoreflector 14. Therefore, the rotational position of the reflector can be determined based on the magnitude of the amount of reflected light received by the photo reflector 14, and as a result, the rotational position of the lens barrel 11, that is, the moving position of the lens frame 12, can also be determined.

FIG. 3B shows that the initial position, intermediate position, and photographing position of the lens barrel can be determined based on the magnitude (H, M, L) of the amount of reflected light. If the reflected light amount is photoelectrically converted by the photoreflector 14 and determined by a voltage, for example, it becomes H when the voltage is 2.5 V or more and is determined to be the initial position, and when it is 2.5 V to 1.5 V, it becomes M. The position is determined to be the intermediate position, and when the voltage is 1.5 V or less, the value becomes L and the position can be determined to be the photographing position.

In a simplified and miniaturized zoom lens barrel, a method called step zoom has been conventionally known. This is a combination of zooming and focusing.
This is performed by a plurality of motors, and a lens stop position in zooming is determined in advance at a plurality of stop positions, and focusing is performed between the stop positions. The present invention can be applied to such a step zoom method.

Although the above-mentioned reflector 13 has three different reflectivities, it may have four or more different reflectivities. Thereby, for example, even in the case of a bifocal lens having only two focal lengths of a standard focal length and a telephoto focal length, if a reflector having four different reflectances is used, a plurality of It is not necessary to provide switches and sensors.

The present invention is not limited to the movement of the lens barrel, but includes a shutter charge mechanism, a lens barrier opening / closing mechanism, a strobe light emitting / retracting mechanism driven by a motor, and switching of the screen size of the IX240 film. The present invention can also be applied to position control of a mechanism (C, H, P) and the like.

[0033]

According to the cameras described in the first to fifth aspects,
Since the infrared light is emitted intermittently, even if an infrared film is used, the image is not exposed to the inside of the screen, the current consumption is reduced, and the life of the power supply battery is prolonged.

According to the moving member detecting device of the sixth and seventh aspects, it is not necessary to provide a plurality of detecting means as in the prior art, so that the configuration of the camera is simplified and contributes to miniaturization.

[Brief description of the drawings]

FIG. 1 is a diagram of a waveform of a reflected light amount according to the related art and the first embodiment.

FIG. 2 is a flowchart according to the first embodiment.

FIG. 3 is a diagram for detecting a position of a lens barrel according to the related art and the second embodiment.

FIG. 4 is an explanatory diagram for moving a lens barrel in a second embodiment.

[Explanation of symbols]

 11 Lens barrel 13 Reflector 14 Photoreflector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 15/03 G03B 15/03 FX 15/05 15/05 17/04 17/04 17/28 17 / 28 EF term (reference) 2H020 MA01 MC13 MC22 MC43 MC44 MC62 MC68 MC73 MC77 MD12 ME21 2H044 DE06 2H053 AA00 CA42 2H083 CC21 2H101 BB05 BB07

Claims (7)

[Claims] 1. A camera that detects the presence or absence of film perforation by a light emitting element that emits infrared light and a light receiving element that receives infrared light, and detects the amount of film being fed. A camera that emits light to detect the presence or absence of film perforation. 2. The light emitting cycle in which the light emitting element emits light intermittently is shorter than a detection cycle for detecting presence of perforation, which is assumed to be the fastest during film feeding. Camera. 3. A light-emitting cycle in which the light-emitting element emits light intermittently is shorter than 1/8 of a detection cycle for detecting presence of perforation, which is assumed to be the fastest during film feeding. The camera according to claim 2. 4. The light-emitting element according to claim 1, wherein a time during which the light is turned off is longer than a time during which light is emitted.
The camera according to any one of claims 1 to 3. 5. A control means for detecting infrared light received by the light receiving element as a signal and controlling film feeding,
The timing at which the control means detects the infrared light is between the timing at which the light emitting element emits light and the timing at which the light emitting element is turned off, and is close to the timing of turning off the light emitting element. 1-4
The camera according to claim 1. 6. A moving member for performing a predetermined movement, a reflecting member having at least three types of reflecting surfaces having different reflectivities, the reflecting surface moving in conjunction with the movement of the moving member, and a light emitting element. And a light-receiving element, and light-reflecting means for reflecting light emitted from the light-emitting element on the reflecting surface and receiving light by the light-receiving element, based on the amount of light received by the light-detecting means, A moving member detection device for detecting a position of a moving member. 7. The apparatus according to claim 6, wherein the moving member is any one of a lens barrel, a shutter charging mechanism, a lens barrier, a strobe light emitting section, and a screen size switching mechanism which are electrically driven. Moving member detection device.