JPH10274738A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability in terms of range-finding in a low-priced camera. SOLUTION: In the instant camera 10, a cylindrical lens barrel part 12 is formed to project from the front surface of the rectangular main body 11 of a camera body in which a film pack is housed. A photographing window 23 for exposing a photographing lens 22 and light projecting and light receiving windows 24 and 25 for exposing light projecting and light receiving elements to the outside are respectively formed on the front surface of the lens barrel part 12. The light projecting and the light receiving elements are arranged below a photographing optical axis 22a in the case of putting the lens 22 in between so that light projecting and light receiving optical axes may be in parallel with the optical axis 22a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera in general, and more particularly, to a camera having a built-in autofocus mechanism, particularly an instant camera.

[0002]

2. Description of the Related Art The applicant of the present invention proposes "Photorama 90 ACE".
(Product Name) Provided. This instant camera is of a low cost type, and has a form in which a lens barrel projects from a body main body. At the top right of the body,
A finder is provided to protrude to the side. The finder is arranged in such a direction that the optical axis of the finder optical system crosses at an arbitrary position on the optical axis of the taking lens arranged on the front surface of the lens barrel.

In this type of instant camera, in order to eliminate the inconvenience of being hidden by a gripped hand,
A strobe light receiving element for an auto strobe and a photometric element for measuring the brightness of a subject are arranged on the front surface of a lens barrel (Japanese Patent Application No. 8-197806).

In the case where a light emitting / receiving element for auto focus is further arranged in such a camera, if the light emitting / receiving element is provided on the front surface of the body body, it may be hidden by a gripped hand as described above. It is desirable to provide it on the front surface of the lens barrel.

Therefore, when a light emitting and receiving element is provided, framing is generally performed with the subject at the center of the finder. It is desirable to arrange in.

[0006]

However, the subject is not always located at a distance where the optical axis of the finder optical system and the photographing optical axis intersect. Therefore, before and after the vicinity of the distance, the light emitted from the light-emitting element hits the object and focuses on the object. On the other hand, when the object is located at a position away from the distance, the light emitted from the light-emitting element is emitted. The light passes through the subject without hitting the subject, resulting in a failed photograph in which the subject is out of focus.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a camera with improved distance measurement reliability at low cost.

[0008]

In order to solve the above-mentioned problems, in a camera according to the present invention, a light projecting element and a light receiving element which constitute a distance measuring element for auto focus are mounted on a photographing lens in front of a lens barrel. Are arranged below and in such a manner that the light emitting and receiving optical axes are respectively parallel to the photographing optical axis. According to this, it is possible to reduce parallax between the light projecting and receiving light axes with respect to the photographing lens and the photographing screen.

[0009]

DETAILED DESCRIPTION OF THE INVENTION An instant camera 10 according to the present invention is described.
Will be described as an example of implementing the above. As shown in FIG. 1, the instant camera 10 has a cylindrical lens barrel 12 having an outer diameter smaller than the front outline shape of the body main body 10 on the front surface of a body main body 11 whose outline shape when viewed from the front is rectangular. Is projected forward.

The body body 10 has a finder 14 at the upper right when viewed from the front, a strobe light emitting unit 15 at the upper left,
Furthermore, in the lower left, the grip part 16, and further in the upper part,
A discharge port 17 from which a photographed film pack is discharged is provided.

The grip section 16 has a power switch 1 on its upper surface.
8 and a shutter button 19 are provided, and the inside is a space for accommodating a power supply battery. In addition, concave portions are provided on the left and right sides of the outer periphery of the lens barrel portion 12 to enhance the holding ability to the left hand to be applied.

The instant camera 10 employs an infrared light active autofocus system, and a distance is measured by pressing a shutter button 19. In addition, a knob 20 for shading control is provided below the front surface of the lens barrel 12. When the knob 20 is slid, the shading is performed based on the value of photometry performed by the pressing operation. Can be controlled.

On the front surface of the lens barrel 12, in addition to a photographing window 23 for exposing the photographing lens 22 to the outside, a light projecting window 24, a light receiving window 25, a photometric window 27, and a strobe light photometric window 26 are provided. ing. In the light emitting window 24 and the light receiving window 25,
Filters for cutting visible light and transmitting only near-infrared light are provided, and a light-emitting element and a light-receiving element are respectively provided behind these filters.

As shown in FIG. 2, the instant camera 10 has a sectional shape in which a main body base 30 in which a film pack storage chamber 29 is formed is wrapped by a front cover 31 and a rear cover 32. The lens barrel 12 is formed integrally with the front cover 31. A drive mechanism such as a developing roller and a scraping claw, a strobe unit, a finder optical system (not shown), and the like (all not shown) are incorporated in the main body base 30. A protruding dark box 33 is integrally formed.

The optical axis of the finder optical system is the imaging optical axis 2
It is arranged in a direction crossing at an arbitrary distance above 2a, for example, at a distance of 2.5 m from the principal point of the taking lens 22. The viewfinder 14 is of a type that does not include a target mark such as an autofocus frame that displays a range to be focused in a view frame in order to reduce costs.

The dark box 33 covers the space between the exposure opening 29 formed inside the main body 30 and the taking lens 22, and has a cylindrical shape tapering forward.
Reference numeral 34 denotes a lid that is opened when the film pack is loaded, and is attached to the rear cover 32.

An exposure unit 35 is fixed to the front end of the dark box 33. More specifically, as shown in FIG. 3, the exposure unit 35 includes a photographic lens holding frame 37, a focus driving mechanism 38, a shutter mechanism 3
9, a light emitting element 40 disposed behind the light projecting window 24, a light receiving element 41 disposed behind the attendance window 25, a light measuring element 43 disposed behind the light measuring window 27, and a strobe light measuring window 26. It is a unit component that is integrated by assembling the strobe light metering element 42 and the like arranged at the back.

The support cylinder 36 has a donut shape in cross section, and a photographic lens holding frame 37 is provided therein with a photographic optical axis 22a.
Is provided so as to be movable along. A shutter mechanism 39 including a motor 39a is also attached to the taking lens holding frame 37. A cam pin 37a is provided on the outer periphery of the taking lens holding frame 37. The cam pin 37a is engaged with the cam groove 44a via a straight guide opening 36a formed in the support cylinder 36. The cam groove 44a is provided in the support cylinder 3
The motor 38a is formed on a rotary cylinder 44 rotatably provided on the outer periphery of the rotary cylinder 6, and is disposed below the rotary cylinder 44.
The lens is displaced along the photographing optical axis 22a by driving from the focus driving mechanism 38 including the focusing lens 38 to focus the photographing lens 22.

A substantially U-shaped element holding frame 45 is mounted on the front surface of the support cylinder 36.
, A light projecting element 40, a light receiving element 41, a photometric element 42, and a strobe light receiving element 43 are integrally mounted. Note that a circuit board including a distance measurement processing circuit (AF circuit) and the like is also integrally attached to the element holding frame 45 on the back side. The photometric element 42 is for measuring the luminance of the object with a photoconductive element such as CdS, and the strobe light receiving element 43 is used for controlling an auto strobe with a photovoltaic element such as a phototransistor. Can be The light projecting element 40 is, for example, an infrared light emitting diode (IRED), and a light projecting lens is integrally incorporated in a front surface of the light emitting element 40. Also, the light receiving element 41
Is, for example, a position sensor (PSD), and a light receiving lens is integrally incorporated in the front of the sensor.

The light projecting element 40 and the light receiving element 41 are, as shown in FIG.
a, and on the circumference of the radius A with the photographing optical axis 22a as the center. Also, the photometric element 43
And the strobe light metering element 42 is also located below the shooting optical axis 22a with the shooting lens 22
Are arranged on a circumference having a radius B different from the radius A with the center as the center. The light projecting element 40 is arranged such that a light projecting optical axis passing through the principal point of the light projecting lens is parallel to the photographing optical axis 22a, and the light receiving element 41 is a light receiving light passing through the principal point of the light receiving lens. The axis is arranged parallel to the photographing optical axis 22a.

Next, the operation of the above configuration will be briefly described.
The assembly of the instant camera 10 is performed by
In addition, drive mechanisms such as a developing roller and a scraping claw, a strobe unit, and a finder optical system (all not shown)
After assembling, the exposure unit 3 is attached to the front end of the dark box 33.
5 and then the rear cover 34 and the front cover 31
Attach.

The exposure unit 35 includes a light projecting element 40, a light receiving element 43, a light measuring element 42, and a light emitting element 40 on the outer circumference of a support cylinder 36 supporting the photographing lens 22 along a circumference centered on the photographing optical axis 22a. Since the strobe light receiving elements 42 are provided, the outer diameter of the lens barrel 12 can be reduced.

Further, since the exposure control mechanical parts are unitized as the exposure unit 35, they can be assembled on another line in advance, and an inspection relating to exposure control can be performed alone. In addition, for example, when an instant camera for manual focusing is separately provided on the market, if only the exposure unit 35 is replaced with a new one, other parts can be commonly used, and cost can be reduced. It is effective.

At the time of photographing, the user holds the grip 16 with his right hand and holds the lens barrel 12 from below with his left hand. At this time, the light emitting window 24, the light receiving window 25,
Since the photometric window 27 and the strobe light receiving window 26 are disposed not on the body main body 11 but on the front surface of the lens barrel 12, it is not necessary to cover these windows with a held hand.

After the holding, the finder 14
, And the shutter button 19 is pressed. Thereby, distance measurement and photometry are performed, and then the shutter is released. In the distance measurement, infrared light is emitted from the light projecting element 40, the infrared light reflected from the object is received by the light receiving element 41, and the object distance is calculated according to the position where the light is received.

The center of the field of view of the finder 14 is set at an arbitrary position on the photographing optical axis 22a. In the case of photographing a person, framing is generally performed such that the face of the person is located at the center of the visual field range viewed through the finder 14. Therefore, the light emitting element 4 of the present embodiment
Since 0 is located below the photographing optical axis 22a, it is necessary to prevent unsuccessful photographs in which the light is always projected to the lower part of the face, that is, the body, and the focus is lost without being projected to the person. Can be.

Further, even if the photographing is performed in a state where the face of the person is not located at the center of the visual field range viewed from the viewfinder 14, the light emitting element 40 is located below the photographing optical axis 22a and the lens barrel. 12, it is located near the taking lens 22 because it is arranged on the circumference around the taking optical axis 22a, and the light projecting and receiving optical axes are parallel to the taking optical axis 22a, respectively. Therefore, there is little parallax with respect to the shooting screen, and therefore, the subject in the center of the shooting screen is surely focused.

By performing the distance measurement, the subject distance is detected, and based on this distance, the focus drive mechanism 38 is driven to focus the photographing lens 22. Thereafter, the shutter mechanism 39 is operated by exposure control based on photometry, and exposure is performed.

The subject light transmitted through the taking lens 22 passes through the dark box 33 and enters the film unit 50 set in the exposure opening 29. If the subject is dark,
The control circuit of the camera activates the auto strobe. When the auto strobe is operated, the strobe light is emitted from the strobe light emitting section 15 toward the subject, and the reflected light is received by the strobe light receiving element 42, and the strobe light irradiation is stopped when the proper exposure is reached.

When the photographing is completed, the exposed film unit 50 is scraped out by a known scraping claw, and after the developing pod is developed by the developing roller 51, the discharge port 1 is discharged.
It is discharged from 7. The image taken after a while is displayed on the discharged film unit 50.

Although the above embodiment has been described as an instant camera, the present invention is not limited to an instant camera, but a camera for loading a brownie-sized photographic film, a camera for loading a 135-type photographic film cartridge, and an IX240 film cartridge. The present invention is applicable to a camera in which a lens barrel having a smaller outer diameter than the front contour shape of the body main body is protrudingly provided on a front surface of a body main body for storing a photographic film, among cameras mounted with the camera and electronic still cameras. be able to.

[0032]

As described above in detail, according to the present invention, the light projecting element and the light receiving element constituting the distance measuring element for auto-focusing are disposed on the front side of the lens barrel and below the photographing lens. In addition, since the projection and reception optical axes are arranged so as to be parallel to the imaging optical axis, parallax with respect to the imaging screen can be reduced.
It is possible to reliably focus on the subject in the center of the shooting screen.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of an instant camera according to the present invention.

FIG. 2 is a sectional view of the instant camera.

FIG. 3 is an exploded perspective view showing a main part of an internal structure of the instant camera.

FIG. 4 is a front view of the exposure unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Instant camera 11 Body main body 12 Lens tube part 22 Photographing lens 22a Photographing optical axis 40 Light emitting element 41 Light receiving element 42 Strobe light receiving element 43 Photometric element

Claims (2)

[Claims] 1. A light source constituting an auto-focus distance measuring element in a camera provided with a lens barrel having a smaller outer diameter than a front contour shape of the body main body protruding from a front surface of a body main body storing a film. A camera characterized in that the element and the light receiving element are arranged below the front surface of the lens barrel near the taking lens, and the light projecting and receiving light axes are respectively parallel to the photographing optical axis. 2. The camera according to claim 1, wherein the camera is an instant camera that stores a film pack in a body.