JPS5981631A - Camera - Google Patents

Abstract

PURPOSE:To project an infrared beam upon the center of a picture frame and to prevent parallax by arranging a light emitting element which emits the infrared beam used for focus adjustment in a focus formation face of a photographic lens. CONSTITUTION:A line 16 shown by a circle on a printed board 15 fixed to a camera body indicates the focus formation face (picture formation face) of the photographic lens 3; a solid-state image pickup element 14 is arranged in this face, and the light emitting element 6 which emits the infrared beam is fitted onto the printed board 15 in the focus formation face except where the solid- state image pickup element 14 is arranged. Therefore, the infrared beam emitted by the light emitting element 6 is converged by the photographic lens 3 and projected upon a subject to be photographed through the center part of the photographic lens 3. An automatic focusing mechanism 4 detects the infrared beam 17 from the infrared beam generation part being reflected by the subject to perform automatic focus adjustment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera having a focus mechanism that measures the distance to a subject and automatically adjusts the focus adjustment FM of the lens to focus the image. .

In still cameras, autofocus operation is performed only when pressing the shutter. On the other hand, in the case of a video camera that converts images into continuous video signals, continuous autofocus operation is required, which is technically difficult, including ensuring responsiveness. Furthermore, a video camera that also has a zoom lens mechanism requires a focusing function with higher precision than that of a fixed focus lens.

FIG. 1 is a perspective view showing a video camera equipped with a conventional autofocus mechanism. Video camera 1 illustrated
The camera is comprised of a camera body 2, a photographic lens section 3 attached to the camera body 2, and an autofocus mechanism 4 attached to the photographic lens section 3. The autofocus mechanism 4 has an infrared beam generating section installed on a substrate 5 that projects an infrared beam onto a subject. That is, first, a light source 6 that emits infrared rays is fixed on the substrate 5. This light source 6 is usually composed of a light emitting diode (LED). A light source lens 7 that focuses the infrared beam emitted from the light source 6 is fixed on the substrate 5 in front of the light source 6. The path of the infrared beam generated by the light source 6 and the light source lens 7 is indicated by a dotted line 8 in the figure. In the figure, the actual line WA9 is an extension of the optical axis of the photographic lens unit 3. As shown in the figure, the infrared beam 8 and the optical axis 9 of the photographing lens unit 3 are 4 meters in front of the camera body 2.
It is set so that it intersects at the point of 0.

This will be discussed later.

The autofocus mechanism 4 further includes a reflected light detection section that detects the reflected light of the infrared beam generated by the infrared beam generation section from the subject hl and the like.

The reflected light detection section is installed on a rotating body 10 that is rotatably installed with respect to the surface of the substrate 5, that is, with respect to the camera body 2. That is, on the rotating body 10, there is a light receiving lens 1 that captures the reflected light of the infrared beam from the subject.
1 is fixed. The reflected light captured by the light-receiving lens 11 is focused on a left light-receiving element 12 and a right light-receiving element 13 that are fixed on the rotating body 10 behind the light-receiving lens 11. The rotating body 10 is equipped with a control device (not shown) so that the reflected light from the subject enters the left and right light receiving elements 12 and 13 equally, that is, the electric output of the left and right light receiving elements 12 and 13 becomes equal. It rotates by. At the same time, focal points i, ll1
A binder 1ri (not shown) rotates the focusing ring of the lens, thereby automatically focusing.

FIG. 2 shows the center of the infrared beam 8 within the rectangular image frame of the conventional video camera explained using FIG.
Indicates the relationship with the distance to the subject.

The image frame has an angle of view of 9° <t? 6x telephoto compared to i quasi)
The case is shown below. As mentioned above, the infrared beam 8 is set to intersect the optical axis of the photographing lens unit 3 at a point 4 meters in front of the camera body 2, so that The infrared beam 8 is located at the center of the image frame as shown. As the distance approaches, the center position of the infrared beam 8 moves above the image frame, and as the distance becomes distant, the center position of the infrared beam 8 moves below the image frame, and finally, Converge 01 to the infinite position ■.

In this way, in the conventional infrared projection method autofocus III, the position of the center of the infrared beam aimed at the subject within the image frame is determined by the distance to the subject.
That's different. As a result, objects other than the selected subject may come into focus.

Or, when shooting in the distance, the foreground is in focus at once.) There is a drawback that so-called balarax occurs.

The present invention has been made to solve the above-mentioned drawbacks, and its main purpose is to project an infrared beam to the center of the image frame.
- To provide a camera with a scraper fence.

In simple terms, this invention is capable of disposing a light emitting element that emits an infrared beam used for focus adjustment within the focal point forming plane of a photographic lens, so that the infrared beam emitted from the light emitting element passes through the photographing lens. This is a camera that can be projected onto a subject.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 3 is a perspective view showing a video camera which is an embodiment of the present invention. The video camera 1 is composed of a camera body 2, a photographing lens section 3, and an autofocus lens 4.

FIG. 4 is an enlarged perspective view of the photographic lens section 3 and autofocus mechanism 4 shown in FIG. 3. As shown in the figure, a solid-state image sensor 14 is mounted on a printed circuit board 15 fixed to the camera body so as to be located at the focal point of the photographic lens 3. Solid-state image sensor 14
converts an optical image into an electrical signal, and its shape is a rectangular plate formed on a silicon substrate. Further, its structure is typically MO8III structure or cco*yli structure. In the figure, printed circuit board 1
A line 16 shown in a circle on 5 is the focal point forming surface (image forming surface) of the photographic lens 3, and the solid-state m-image element 14 is arranged within this focal point forming surface.

Further, a light emitting element 6 (usually an LED) that emits an infrared beam used for focus adjustment is mounted on the print board 15 within the focus formation plane excluding the portion where the solid-state image sensor 14 is arranged. There is.

Therefore, the infrared beam emitted from the light emitting element 6 is focused by the mirror lens 3, passes through the center of the photographic lens 3, and is projected onto the subject, as shown by I@17 in FIG. . This light emitting element 6 has an A-tofocus t! This constitutes the infrared beam generating section of the M structure 4.

O1-) The A-cass mechanism 4 further includes a reflected light detection unit that detects the reflected light from the subject of the infrared beam 17 generated from the infrared beam generation unit (indicated by a dotted line in FIG. 3). There is. This reflected light detection section will be explained below. First, a substrate 5 is fixed to the photographing lens section 3. On this substrate 5, a rotating body 10 is provided with a rotating bin 19.
It is mounted so that it can rotate around τ. Rotating body 10
A light-receiving lens 11 that captures the reflected light of the infrared beam from the subject is fixed on the top. The reflected light captured by the light receiving lens 11 is transmitted to a left light receiving element 12 and a right light receiving element 13 fixed on the rotating body 10 behind the light receiving lens 11.
focused on. The light receiving lens 11J3 and the left and right light receiving elements 12.13 constitute a reflected light detection section. The amount of light incident on each light receiving element 12 and 13 is unbalanced depending on the direction in which the reflected light from the subject arrives.

A reversible rotary motor 20 is further installed on the substrate 5. This reversible rotary motor 20 can rotate in both directions depending on the supplied power and polarity.

A motor pinion 21 is fixed to the end of the rotating shaft of the motor 20, and transmits its rotational force to a gear 22. Gear A72
2 is fixed to a shaft 23, and furthermore, on this shaft 23,
As shown, the eccentric cam 24 and the drive pinion 2
5 is fixed. Shaft 23, gear 22, eccentric cam 24
The drive pinion 25 and the drive pinion 25 rotate together, and the shaft 23 is rotatably supported on the substrate 5 by a bearing (not shown).

The photographic lens unit 3 has a focal point 1lii for adjusting the focal point.
It is equipped with a knot ring 3a. Also, in the photographic lens section S,
A gear 26 is attached to rotate integrally with the focal point ring 3a. This gear 26
is in mesh with the drive pinion 25 as shown.

As mentioned above, the rotating body 10 is rotatable on the substrate 5 around the rotating pin 19, and furthermore, the rotating body 10 is always urged to rotate in one direction by the tension spring 27. . The end of this rotation is defined by the cam engaging portion 28 on the light receiving lens 11 coming into contact with the eccentric cam 24.

As mentioned above, the left and right light receiving elements 12 and 13 are unbalanced depending on the direction of the reflected light arriving therein.

In that case, there will be a difference in electrical output, which will cause the reversible rotary motor 20 to rotate by a differential amplifier (not shown). This rotation of the motor 20 is transmitted to the motor pinion 21 and the gear 22, and the eccentric cam 24 also rotates.

Since the cam engaging portion 28 of the light receiving lens 11 is always in contact with the eccentric cam 24, the rotating body 10 rotates on the substrate 5 in accordance with the rotation of the eccentric cam 24.

In this way, the rotating body 10 automatically performs tracking so that the amounts of reflected light arriving at the left and right light receiving elements 12 and 13 are equal. Further, at the same time, the drive pinion 25 rotates the gear 26 and the focus adjustment ring 3a integrated with the gear 26, so that an autofocus operation is also performed.

To summarize the above, the autofocus Δ-focus 114 of the camera according to the present invention functions as follows. That is, triangulation is performed between the infrared beam (fixed optical axis) generated by the light emitting element 6 and the photographing lens 3 and the rotating optical axis constituted by the left and right light receiving elements 12, 13 and the light receiving lens 11. By providing the eccentric cam 24 with the rJA number relationship between the moving angle and the distance, the rotation angle corresponding to the distance information to the subject is automatically given to the photographic lens unit 3.
This allows automatic focus adjustment, or auto-tracking.

In the above explanation, a solid-state imaging element was used as the light converter for converting the L1 optical image into an electrical signal, but this was a vacuum tube type image element. Sentence/May be. However, it should be noted that no matter which Kourb's image grip is used, it must have a 1.4 shape so that the light emitting element can be installed within the focal point forming plane of the photographic lens (
It must not be pulled, and it must be arranged like that (-1).

Furthermore, although a video camera was used in the embodiments described above, the present invention is not limited thereto. In short, this invention LJ
', A-l~fufuj-kass VAS can be effectively used in cameras.

According to this invention, the infrared beam emitted from the light emitting element is narrowed down by the photographing lens. !
Since the infrared beam is projected onto a single object, the infrared beam can always be projected onto the center of the image regardless of the distance to the subject. Shi1ζ is Tsumata, conventional 71-1
-] It is possible to eliminate the balax that was a drawback of cameras equipped with an A-cass mechanism, making it extremely convenient to use.1

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a video camera equipped with a conventional autofocus mechanism. Figure 2 shows the center of the infrared beam within the image frame taken by a conventional video camera, and
FIG. 3 is a diagram showing the relationship with the distance to the subject. FIG. 3 is a perspective view showing a video camera which is an embodiment of the present invention. FIG. 4 is an enlarged perspective view of the autofocus mechanism and photographic lens section shown in FIG. 3. In the figure, U11 is a video camera, 3 is a photographic lens unit, 3
a is a focus adjustment ring, 4 is an autofocus m mechanism, 5 is a substrate, 6 is a light emitting element, 10 is a rotating body, 11 is a light receiving lens, 12 is a left light receiving element, 13 is a right light receiving element, 14 is a solid state image sensor, 15 is a printed circuit board, 19 is a rotary bin, 20 is a reversible rotary motor, 21 is a motor binion, '22 is a gear, 23 is a shaft, 24 is an eccentric cam, 25 is a drive binion, 2
6 is a gear, 27 is a tension spring, and 28 is a cam engaging portion.

Claims (1)

[Claims] A light-emitting element that emits an infrared beam used for focus adjustment, and a photoelectric conversion device that converts an optical image into an electrical signal and is placed within the focus forming plane of the photographic lens. In the camera having a part, the light emitting element is arranged within a focus forming plane of the photographing lens excluding the part where the photoelectric conversion part is arranged, so that the infrared rays emitted from the light emitting water element A camera, in which a beam can pass through the projection lens and be projected onto a subject.