JPS6154778A - Focus matching device of video camera - Google Patents

Abstract

PURPOSE:To obtain a video camera which is simple and low-priced in construction, can match a focus for various interchangeable lenses and is excellent in operability by matching a focus by shifting an image pick-up surface without shifting a lens. CONSTITUTION:An image pick-up device 7 is shiftably installed in the light shaft direction of an image pick-up lens 17 and by shifting the image pick-up device 7, a distance L between a lens fitting part 2 and an image pick-up surface 7a of the image pick-up device 7 can be changed. An object light, object information passing through the image pick-up lens 17, makes a light incidence on the image pick-up device 7. Having a focusing signal extracting circuit 18, which is a focusing signal extracting means using sharpness of an object received at part of the image pick-up surface 7a of the image pick-up device 7, a signal processing circuit 13 and an piezo-electric element control circuit 14, a surface wave motor 5 is controlled and driven by the output signal of the control circuit 14, an image pick-up device fitting part 16, a fitting member of the image pick-up device 7 is shifted and a flange-back distance L is changed.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an automatic focusing device for a video camera.

2. Description of the Related Art As an automatic focusing device used in conventional video cameras, for example, devices shown in FIGS. 5 and 6 are known. According to this, a photographing lens 3 is attached to a lens attaching portion 2 of a video camera body 1. The photographing lens 3 is provided with a focus ring 4 for focusing, and a gear 5 that meshes with this by 4 degrees is attached to the video camera body 1.
The photographic lens 3 is driven by a motor M attached to the camera and expands and contracts in the optical axis direction. In the case of the configuration shown in FIG. 3, this motor M is connected to the imaging device 7 and the signal processing circuit 8 side by a light splitter 6 provided in the camera body I on the optical axis of the photographic lens 3.) The foreign loan t1+ that has been rejected is distributed to the verification detection device 9, and is further driven and controlled via a signal processing circuit 10 and a motor drive circuit 11. In addition, in the case of the configuration shown in FIG. 6, the driving (jlijlυ11) is performed from the rQ device 7 via the focusing signal extraction circuit 12 and the No. 13 processing circuit 13 as focusing signal extraction means. The force sling 4 is rotated until the goldfish signal is output (feedback to the motor M), and the photographing lens 3 is moved one turn in the optical axis direction by the rotation of the helicoid according to FIG.

However, in these conventional devices, the photographic lens is responsible for the mechanism of the automatic focusing device, and the six photographic lenses, which have a very complicated mechanism, are not fixed but interchangeable. If so, it is necessary to create a mechanically and circuitically compatible d-ring drive form for the various interchangeable lenses in use, which increases the complexity of the mechanism, increases the weight, and increases the price.
The rise in the number of people living in Japan has become an increasingly unavoidable problem. In addition, there are problems such as motor noise and gear noise caused by the motor, as well as problems such as motor noise and gear noise. There was a risk that it would become impossible.

Aspects of the Invention This invention was made to solve the above-mentioned problems, and the structure is simple and inexpensive, and focus adjustment can be easily performed for various interchangeable lenses. It is an object of the present invention to provide a video camera with four superior operability.

Structure of the Invention This invention is characterized by focusing by moving a 1if plane instead of moving the lens.
・This is Tosurano.

The present invention will be explained below based on the drawings.

FIGS. 1 and 2 are diagrams showing an embodiment of the present invention, and in the figures, parts that are the same or equivalent to the conventional ones are given the same reference numerals, and redundant explanations will be omitted.

In FIG. 1, the photographing lens 17 may be either a fixed type or an exchangeable type, and is attached to the lens attachment portion 2 of the video camera body 1 in a non-detachable or detachable manner. A device 7 is provided movably in the optical axis direction of the photographic lens 11, and by moving the photographing device 7, the distance L (hereinafter referred to as this) between the lens mounting portion 2 and the imaging surface 7a of the photographing device 7 is adjusted. It is called the Frandepac distance.

) can be changed.

The object light, which is object information, passes through the photographic lens 17 and enters the imaging device 7 . A focusing signal extraction circuit 18 and a signal processing circuit wI+ are goldfish signal extraction means using the sharpness of the object image received on a part of the imaging surface 7a of the imaging device 7.
3. This control circuit I4 has a piezoelectric element control circuit 14.
The surface wave motor 15 is controlled and driven by the output signal of , and the I-most image device attaching portion (6), which is a mounting member of the image pickup device 7, is moved to change the Frandepack distance.

Next, the configuration of the surface wave motor 15 will be explained with reference to FIGS. 1 and 2. The imaging device 7 is fixed to the imaging device mounting portion 16 and moves along the rail 15c in the optical axis direction of the lens +7. Piezoelectric elements 15a are provided at both ends of the rail 15c,
15b is attached and the force piezoelectric element 1' is oscillated so that the other force piezoelectric element absorbs the elastic wave v1', thereby preventing the generation of standing waves and avoiding the movement of elastic waves. It becomes possible. Figure 2 shows the imaging device 7 and the imaging device installation 1.
116 has hollow rectangular tubes 16a and 16b, the imaging device 7 is placed inside the large tube 16a, and the small tube IGb is placed inside the large tube 16a.
A slider part +5d made of an elastic body is incorporated therein, and the slider part +5d is brought into contact with the rail 15c. rail! If the surface acoustic wave moving to 5c is propagating, the imaging device mounting portion I6 and the imaging device g17 move 4 degrees in the opposite direction to the traveling direction of the surface wave. The direction of movement is determined by the piezoelectric element 15.
It is reversed by changing the phase of the AC voltage added to a and I5b.

Therefore, the Fran de Pack distance IL changes by driving the surface wave motor I5. As a result, a new subject t1
1 report is received and the same operation is 1'? Wow 41. A, 1.
l (If it is, the surface wave motor 15 is stopped, and if it is not in focus, these operations are repeated. If it is in focus, a focused image is formed on the imaging surface 7a of the imaging device 7,
The signal passes through the signal processing circuit 8 and goes to the TV. +
9, the focused image will be broadcast.

1-1 Jl (water groove 11 (
The li material has nine parts compared to the conventional device, including the rail 15c, piezoelectric elements 15a and 15b, and the image pickup device mounting part I6.
ci! 1li1 etc. become unnecessary. It should be noted that the type of deaf person who changes the flange bank distance nCL is not limited to the focus detection method shown in the embodiment shown in FIG. In addition, by changing the flange back distance of 1 m L according to the focus detection signal, the photographing lens does not involve the drive system when focusing, allowing various interchangeable lenses to be easily applied, and using a surface wave motor. This eliminates the need for a complicated drive system, making it possible to manufacture the product at low cost, and improving operability by making it smaller and lighter, which also improves mass production and reliability. In addition, the movable parts are not exposed from the camera body, but are inside, so you can safely take pictures without interfering with other objects.

FIG. 3 is a diagram showing another embodiment of the present invention, and FIG.
It is the same as the one shown in Figures 5 and 6.
I minutely (J same 1.1 tl' l-ζ city 1.!/
In the embodiment shown in FIG. 3, the photographic lens 17 is 1id.
It is a formal and replaceable type, and it is attached to the lens mount 81!2 on the camera body I.

The imaging device 7 moves in the optical axis direction of the photographing lens 17 (ρ automatic lj
°, and the flange back distance ■7 can be changed.

The limb photographing information and limb photographing light that has passed through the photographing lens 17 is incident on the first imaging device 7. Imaging surface 7a of this imaging device 7
A control drive circuit that controls and drives a focus signal extraction circuit I8, a signal processing circuit 13, and a piezo actuator 20, which is a focus signal extraction means using a sharp IA melon of a limb image received in a part of the 14 is (-f). The piezo actuator 20 is controlled and driven by the output signal of the control drive circuit I4, and the displacement of the piezo actuator 20 is transmitted to the imaging device 7 by the displacement amplification device 15'. Installation RL < 4A
d5 is amplified and transmitted to the image device mounting part I6, causing 1 hyperactivity.
Change the flange 1 < ivy distance.

The lower part of the piezo atticoator 20 is fixed to the Noyano by a bold member 21. Moreover, the displacement amplification device 1
The lever 15'a at 5' has one end fixed to the tip of the piezo actuator to prevent the maximum displacement of the piezo actuator. The other end is interlocked with Viage actuator 2.
The displacement m of the tip of o is amplified and transmitted to the imaging device mounting section 16. In the displacement amplification device +5' as described in nfj, the lever 1 is
5'a rotates to move the image pickup device mounting portion 16.5'a in the direction of displacement of the piezo actuator 20. The imaging device 7 moves. This direction of movement can be reversed by changing the polarity of the voltage applied to the piezo actuator 20.

Therefore, 1ljl rJ of Pieve' actuator 20
The flange back distance changes depending on the I+ drive. As a result, new object information is entered, and similar operations are performed. If the object is in focus, the piezo actuator 20 is stopped at that position, and if the object is not in focus, these operations are repeated. Figure 4 is a general example of the characteristic diagram of a BiJ actuator.
The control drive circuit 14 for the eta is also l! ii Can be elementaryized. When focusing as described above, the imaging surface 7 of the imaging device 7
A focused image is formed on a, which passes through a signal processing circuit 8 and is broadcast on a telephoto receiver I9.

As mentioned above, the dead tree (114) component of the automatic focusing device of this embodiment is composed of the Vinny Shiakchi Unique 20 and the displacement amplification device 15, and the number of parts is reduced compared to the conventional device. Because of its high-speed response, there is no need for a conventionally complex motor speed reducer or transmission mechanism.Here, the deaf person who changes the 7-run nova distance #11. It is not limited to this and other deaf cups may be used.If the displacement amount of the Vieso actuator is large, the displacement amplification device I5 may be omitted.
.

In addition, the displacement n of the displacement amplifying device I5 (the amplifying means is not limited to the method as in the 3M embodiment, but 11!!'s jl!!' + 4., '9 and 1. Of course -ζ
＋'5 'J 11 Effects of the Invention JI J The invention described above is for a video camera to achieve focus alignment by moving the imaging device without moving the photographing lens when aligning the yH point. By doing this, the photographic lens would no longer be involved in the drive system when focusing, making it easier to use a variety of interchangeable lenses, eliminating the need for a complicated drive system, and making video cameras cheaper. And 6, the smaller size and lighter weight improves operability, as well as mass productivity and reliability.

Furthermore, unlike conventional video cameras, the movable part is not exposed from the camera body, but is located inside the camera body, allowing safe and reliable photography without interfering with other objects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the video camera of the present invention, FIG. 2 is a sectional view showing the relationship between the surface wave motor and the imaging device mounting part in the embodiment of FIG. 1, and FIG. A block diagram showing another embodiment of the video camera of the invention,
Figure 4 is the special P1 curve of Vinny-Siatache Go-Yu, Section 5, Section 1: Figure 6, f, 1. i + ゛ti An example of this high 1 o camera is a 2° 4° block diagram, and Fig. 7 shows a 4° block diagram of the device shown in Fig. 5.
5 Helicoid 1, γ position and electric 11. The relationship with 2 do 4
′ is a graph. 1...Camera body, 2...Photographing lens mounting part, 7...
1ffi image device, 7a...imaging surface, 14...piezoelectric element: 1-control circuit, 15...surface wave motor, +5'
・Displacement amplification device, 15a, 15b...piezoelectric element, 1
5C...Rail, 15d...Slider part, I6.
...Imaging device mounting part, 17...Photographing lens, 18...
・Focus IJ No. hII output circuit,... Plandepack distance, 20... Piezo actuator.

Claims (4)

[Claims] (1) In an automatic focusing device for a video camera that receives copy object information from a photographic lens into an imaging device, means for changing the distance between the lens mounting portion and the imaging surface of the imaging device in the optical axis direction. An automatic focusing device for a video camera, comprising: (2) It has a focus signal extracting means for extracting a focus signal from the copy object information received by the photographing device, and moves the imaging surface of the imaging device in the optical axis direction in accordance with the output of the focus signal extracting means. An automatic focusing device for a video camera according to claim 1, further comprising driving means. (3) The driving means for moving the imaging plane in the optical axis direction uses a surface wave motor that drives the moving body using high-frequency elastic waves generated on the surface of the elastic body.
Automatic focusing device for a video camera as described in Section 1. (4) The automatic focusing device for a video camera according to claim 2, wherein the driving means is a piezo actuator.