JPH0466909A - Auto-zoom/focus mechanism - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a video camera by providing Hall elements which are installed to a fixed lens barrel at prescribed intervals and detect the advancing and retreating quantities of the fixed lens barrel from magnetic fluxes of magnet members. CONSTITUTION:In this auto-zoom/focus mechanism, Hall elements 11a, 11b, and 11c respectively receive magnetic fluxes phi from magnet tapes 12a, 12b, and 12c when a lens barrel 2 for zooming rotates or moves forward and backward. The distance (s) to an object 7 is detected on the basis of the output of each Hall element 11a, 11b, and 11c and detected results are fed back to a zoom driver 6d. Therefore, the Hall elements 11a, 11b, and 11c can be arranged close to each other, since the interference between each Hall element by magnetic fluxes is small. In addition, the occupying space of the Hall elements can be reduced, since the elements themselves are small in size. As a result, a video camera can be reduced in size and thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic zoom/flash mechanism for, for example, a video camera.

(Prior Art) A video camera is a device in which an image is focused by a lens, an imaging device for photoelectric conversion is placed at that position, and an electrical signal is extracted by scanning the image. This imaging device includes an imaging tube and a CCD.

There are solid-state image sensors such as MOS. Traditionally, image pickup tubes have been the mainstream, but recently, as the performance of solid-state image sensors has improved, they have become smaller and lighter, and home video cameras have become popular.

Auto zoom/focus, which is one of the functions of such a video camera, automatically adjusts zoom/focus. The focus is automatically adjusted using an active method that emits infrared rays or ultrasonic waves and focuses based on reflected information, and a passive method that detects the phase difference of the incident light or checks the high frequency level of the signal. .

Figure 6 shows an example of an auto-zoom/focus mechanism that uses the above-mentioned active method or passive method to take one step of zooming/focusing. ing. In addition, it is for zoom! [2] is capable of moving forward and backward with respect to the fixed lens barrel 1 as the gear unit 3 rotates, and the zoom lens (not shown) housed inside the fixed lens barrel 1 (not shown) (omitted) in the optical axis direction.

A focusing lens barrel 4 is rotatably attached to the tip of the zoom lens barrel 2 by the driving force of a gear portion 5, and as the focusing lens barrel 4 rotates, a focusing lens (not shown) rotates.
is displaced in the optical axis direction.

The auto zoom/flash drive circuit 6 has an object 7
A detection sensor 6a is provided that detects the subject 7 by receiving reflected light, such as infrared light, from the camera. The drive circuit 6 also includes a gear drive circuit 6b for supplying driving force to the gear section 5 based on the detection result from the detection sensor 6a.
A screwdriver 6C is provided to control the operation of the screwdriver 6C. Furthermore, the drive circuit 6 is provided with a zoom driver 6d that supplies a control signal to the gear drive circuit 6b based on a preset degree of zoom.

When zooming is designated, the gear drive circuit 6b supplies driving force to the gear section 3 based on a control signal from the zoom driver 6d. As a result, the zoom lens barrel 2 moves forward and backward relative to the fixed lens barrel 1 while rotating. At the same time as the rotation and forward/backward movement of the zoom lens barrel 2 are completed, the detection result from the detection sensor 6a is taken into the focus driver 6c, and based on this, the focus driver 6C controls the gear drive circuit 6b to Take a scrap of the liquid.

Here, the distance to the subject 7 is, for example, as shown in FIGS. 7 and 8.
It is detected by the position detection mechanism shown in the figure.

That is, a notch hole 1a is formed in the fixed lens barrel 1, and a photoreflector 8 is provided at a position covering the notch hole 1a.
A + 8 b + 8 c are provided.

Inside the zoom lens barrel 2, there is a zoom lens (not shown).
is retained. In addition, on the circumferential surface of the zoom lens barrel 2,
Aluminum tape 10 B+ 10 br10c is attached.

And each photoreflector 8 a + 8 b +
8 When c emits light by itself, this causes each aluminum tape 10
a+ 10 br I Oc and reflected again by each photoreflector 8 a + 8 b + 8 c
It is now being incorporated into the

When detecting the distance S to the subject 7, it is performed as shown in FIG. 8, for example.

That is, as the zoom lens barrel 2 rotates and moves forward and backward, the reflected light from each of the aluminum tapes 10a and 10br10c is reflected by each photoreflector 8a.

Incorporated into 8b + 8c. At this time, upon receiving the reflected light, each photoreflector 8a+8b+8c outputs a "high" level signal.

As shown in FIG. 9, each photoreflector 8
The focal length is detected by the combination of outputs from a*8b+8c, and this detection result is fed back to the zoom driver 6d.

(Problems to be Solved by the Invention) As described above, video cameras in recent years have become extremely easy to operate due to the addition of auto-zoom/focus functions, giving them the pleasure of photographing subjects.

However, these conventional video cameras are inconvenient to carry and operate these days, as they are increasingly used by women and children.

That is, in the conventional video camera described above, in order to avoid mutual interference of light from the photoreflectors 8B+8br8c, it is necessary to arrange the photoreflectors at predetermined intervals. Further, since a photoreflector requires a light emitting element, a light receiving element, and circuits associated with these elements, it is necessarily large, and the installation of these elements requires a large space.

For this reason, the fixed lens barrel 1, the zoom lens barrel 2, etc. become larger, and the auto zoom/focus mechanism itself becomes larger, so it is difficult to make the video camera smaller and lighter. It is a hindrance. Therefore, when carrying or operating the device, the weight of the device becomes a burden.

The present invention was made in response to these circumstances, and
An object of the present invention is to provide an auto zoom/focus mechanism that can reduce the size and weight of a video camera.

(Means for Solving the Problems) The present invention provides a zoom system that moves forward and backward while rotating with respect to a fixed lens barrel.
In an auto zoom/focus mechanism that detects the position of the subject according to the amount of movement of the focusing lens barrel and zooms/focuses based on the detection result, a predetermined interval is provided on the circumference of the zoom/focusing lens barrel. The present invention is characterized in that it includes a magnet member provided at a distance from the fixed lens barrel, and a Hall element provided at a predetermined interval from the fixed lens barrel and detects the amount of advance and retreat using magnetic flux from the magnet member.

(Function) In the auto zoom/focus mechanism of the present invention, zoom/focus
When the zoom/focus lens barrel rotates and moves back and forth with respect to the fixed lens barrel when taking a single image, the Hall element produces a Hall effect due to the magnetic flux from the magnet member. At this time, the output due to the Hall effect is obtained at every predetermined interval of the magnet member provided on the circumferential surface of the zoom/focus lens barrel.

Therefore, since the interference caused by magnetic flux between the Hall elements is smaller than the interference caused by conventional light, the Hall elements can be arranged close to each other.

Furthermore, in terms of its function, the Hall element itself is much smaller than a conventional photoreflector, so the space it occupies is much smaller than that of a conventional photoreflector.

In other words, the conventional photoreflector is necessarily large because it requires a light emitting element, a light receiving element, and associated circuits. On the other hand, the Hall element in the present invention does not require a complicated circuit configuration because it only has the function of sensing the magnetic flux from the magnet member.

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings. Note that parts common to those in FIGS. 5 to 7 are designated by the same reference numerals, and redundant explanations will be omitted.

1 to 3 show an embodiment of the auto zoom/focus mechanism of the present invention.

That is, instead of the photoreflectors 8a, 8b, 8c, Hall elements 11a, llb are placed at positions covering the notch hole 1a of the fixed lens barrel l shown in FIG.

11c is provided.

Further, magnetic tapes 12a+12b+12c are attached to the circumferential surface of the zoom lens barrel 2 shown in FIG. 7 in place of the aluminum tapes 10a+10tz 10c.

Here, each Hall element 11a+ 11b+ llc
is made of, for example, indium antimony or gallium arsenide, and its dimensions are 1.5 x 1.5 x 0.3 t
(mm).

In addition, each magnetic tape 12 a r 12 b
+12c is made of, for example, a base material such as rubber, metal, or plastic whose surface is magnetized or a magnetic material is formed on the surface. Dimensions are specified length x 1, OXo, 4t
(mm).

The gap between each Hall element 11a, 11b+llc and each magnetic tape 12a, 12b, 12c is 0.3
(mm).

The distance between the centers of each Hall element 11a, 11b+Ilc is 2 (mm).

In addition, each Hall element 11a, Ilb+llc,
For example, as shown in FIG. 4, a bias is applied to each magnetic tape 12al 12b.
When receiving the magnetic flux φ from + l 2 c, the flow of electrons is bent in the right angle direction, and the magnetic flux φ is created between the other electrodes B1-B2.
A voltage VH proportional to the strength of is generated. As a result, as the zoom lens barrel 2 rotates and advances and retreats, each Hall element 11a, 11b, llc moves to each magnetic tape 1.
2a, 12b.

12c is detected.

In contrast, conventional photoreflectors 8a, 8b, 8c
As shown in Figure 1(b), its dimensions are 3.6X
It is said to be 2.6X1.6t (mm).

In addition, conventional aluminum tape lOa, tob.

10c has a predetermined length x3. OXo, 1t (
mm).

The arrangement interval of each photoreflector 8a, 8b, 8c is as follows:
The distance between the centers is 4 (mm).

As described above, in the auto zoom/flash mechanism of the present embodiment, as the zoom lens barrel 2 rotates and advances and retreats, the Hall elements 11a, 11b, 11c move to the respective magnetic tapes 12a, 12b.

It receives magnetic flux φ from 12c.

At this time, the output from each Hall element 11a, llb, 11C has a voltage waveform shown in FIG. 5, for example.

In other words, the Hall element 11a, as shown in FIG.
Outputs maximum value 4.40V. At this time, Hall element 1
1b outputs a maximum of 4.56 V, as shown in FIG. Further, the Hall element 11c has the same v;1J(c
), it outputs a maximum value of 4°56V.

In this way, each Hall element 11a+11b.

By applying these combinations to the matrix shown in FIG. 9 based on the output from the camera, the distance S to the subject 7 is detected, and this detection result is fed back to the zoom driver 6d.

In this way, in this embodiment, when detecting the distance to the subject, a Hall element was used that outputs a "high" level using the magnetic flux from the magnetic tape. Therefore, since the interference caused by magnetic flux between the Hall elements is smaller than the interference caused by conventional light, the Hall elements can be arranged close to each other.

As a result, as shown in FIGS. 3(a) and 3(b), for example, the distance between the centers could be reduced to about 1/2 compared to the conventional one.

Moreover, as shown in FIG. 2(a) and FIG. 2(b),
The thickness of each Hall element could be reduced to about 115 mm compared to conventional photoreflectors.

Furthermore, the gap between each Hall element and each magnetic tape is
Compared to the conventional gap, the gap could be reduced to about 375.

Furthermore, the volume is approximately 1/8 compared to the conventional one.
I was able to do it to a certain extent.

In other words, the conventional photoreflector is necessarily large because it requires a light emitting element, a light receiving element, and associated circuits. On the other hand, the Hall element in this embodiment requires only the function of sensing the magnetic flux from the magnetic tape, and therefore does not require a complicated circuit configuration.

Therefore, the auto zoom/focus mechanism of this embodiment is much smaller than the conventional one, and by employing this mechanism, it is possible to make the video camera smaller and thinner.

(Effects of the Invention) As explained above, according to the auto zoom/focus mechanism of the present invention, since the interference caused by magnetic flux between each Hall element is smaller than the interference caused by conventional light, each Hall element can be brought close to each other. can be arranged. Also, in terms of its functionality,
Since the Hall element itself is much smaller than a conventional photoreflector, the space it occupies can be made much smaller than that of a conventional photoreflector.

As a result, auto zoom/focus a in the present invention
By employing ttit, it is possible to make the video camera smaller and thinner.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing essential parts of an embodiment of the auto-zoom/focus mechanism of the present invention, and FIGS. 2(a) and 3(a) are hall elements of the auto-zoom/focus mechanism of the present invention. Figures 2(b) and 3(b) are for explaining its function, and are diagrams showing a conventional auto-zoom/flash mechanism photoreflector and aluminum tape. , 4rgJ, and 5 are diagrams for explaining the action of the Hall element in Figure 1, Figure 6 is a diagram showing an example of an auto zoom/focus mechanism, and Figure 7 is a diagram for explaining the action of the Hall element in Figure 1.
8 and 8 are diagrams showing the main parts thereof, and FIG. 9 is a drawing showing the combination of outputs from each photoreflector in FIG. 7 and the focal length based on the combination of outputs. DESCRIPTION OF SYMBOLS 1... Fixed lens barrel, la... Notch hole, 2... Zoom lens barrel, 6... Drive circuit, 6a... Detection sensor,
6b... Gear drive circuit, 6c... Focus driver, 6d... Zoom driver, 11a+ Ilb+
llc...Hall element, 12a, 12b+1
2c...Magnetic tape. Patent applicant: Representative of Pioneer Co., Ltd.
Patent Attorney Nobuaki Kobashi Patent Attorney Nobuaki Kokura-h- Shu No. 8

Claims (1)

[Claims] (1) In an auto zoom/focus mechanism that detects the position of the subject according to the amount of movement of a zoom/focus lens barrel that moves forward and backward while rotating with respect to a fixed lens barrel, and zooms/focuses based on the detection results. A magnet member is provided at a predetermined interval on the circumferential surface of the zoom/focus lens barrel, and a magnet member is provided at a predetermined interval on the fixed lens barrel, and the amount of advance and retreat is controlled by the magnetic flux from the magnet member. An auto zoom/focus mechanism characterized by comprising a Hall element for detection.