Video recording system with focusing device

A video system includes a video camera for obtaining image signals, and a video recorder for recording the image signals. Driving power provided in the recorder, for loading a tape over a recording drum, is transmitted to the video camera after the tape is fully loaded on the drum. Movable parts in the video camera such as an automatic focus adjusting mechanism, can then be driven by the driving power source in the recorder.

FIELD OF THE INVENTION 
The present invention relates to a video system comprising a video camera 
for obtaining image signals and a video recorder for recording the image 
signals. 
DESCRIPTION OF PRIOR ARTS 
Quite recently, the video tape recorder or so-called VTR is becoming more 
and more compact. A portable VTR has become popular together with a video 
camera for outdoor photographing. However, at present, the video camera is 
constructed separately from the VTR, and they are connected to each other 
by way of cables. This arrangement therefore is inconvenient to handle. 
Consequently, various kinds of video cameras each integrated with a VTR, 
have been proposed. Presently, however, the proposed systems are not 
practical because of problems in volume and weight. It is of course 
necessary that such systems be compact and light to enhance their 
portability and operability. 
SUMMARY OF THE INVENTION 
One object of the present invention is to offer a compact and light video 
system including a video camera and a recorder, wherein the driving power 
produced in the video recorder for recording an image signal is used as 
driving power for movable parts of the video camera. 
Another object of the present invention is to offer a video system in which 
the camera can be mounted on the recorder in such a manner that the 
driving power of the recorder can be transmitted to the video camera. 
Yet another object of the present invention is to offer a video system in 
which the video camera has an automatic focusing lens for which the 
driving power is obtained from the recorder. 
Further objects of the present invention will be obvious from the 
description made hereinbelow with reference to the drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS 
FIG. 1 shows an outline of the principal mechanical construction of an 
embodiment of the video camera and VTR of the present invention. In the 
drawing, a VTR V is arranged for recording a picture signal on a tape 
shaped recording medium, and a camera C converts the object image into 
electrical signals. The VTR V and the camera C are connected to each other 
with a tripod screw 1 and a nut 2. The camera C is provided with an 
automatic focusing lens 3, in such a manner that an object image is formed 
on an image pick up tube 5 through the lens 3 and a diaphragm 4. Above the 
automatic focusing lens 3, a distance measuring device S which measures 
the distance up to the object, trigonometrically in a conventional way, is 
provided. In the distance measuring device, reflecting mirrors 6 and 7 are 
arranged so as to face distance measuring windows 6' and 7' formed on both 
ends of a certain determined base line on the front of the casing. Image 
forming lenses 8 and 9 are provided for receiving the light from the 
reflecting mirrors 6 and 7 so as to form a distance detecting image. A 
reflecting prism 10 is provided for deviating the image light beam from 
the image forming lenses so that they form a base line distance measuring 
optical system. A linear image sensor 11 such as CCD is arranged at the 
position which the image forming light beam reaches from the prism 10 (the 
focusing plane of the image forming lenses 8 and 9). A distance and focus 
detecting circuit 12 detects the distance to the object from the image 
scanning output of the image sensor 11, and detects the focusing state of 
the lens 3, namely in focus, near focus or far focus by means of the data 
obtained by the distance detection and data for representing the position 
of the automatic focusing lens 3, as explained later, on the optical axis. 
The detecting circuit 12 includes IC chips. A coupler 13 is arranged to be 
connected to a coupling 14 explained later, at the side of VTR on the 
camera bottom, wherein the coupler is engaged with a focusing gear 18 via 
gears 15, 16 and 17. Thus, along with the rotation of the gear 18 the 
automatic focusing lens 3 advances or retracts along the optical axis in a 
conventional way. A grey code signal plate 19 includes a combination of a 
conductive and a non-conductive pattern for indicating the position of the 
focusing lens along the optical axis with digital words of a certain 
determined number of bits, and is arranged on the circumference of the 
focusing gear 18. A brush 20 is provided at a fixed position so as to be 
in contact with the grey code signal plate 19, whereby the data 
representing the position of the lens 3 along the optical axis is obtained 
through the brush 20 as a digital signal with a certain determined number 
of bits, and delivered to the distance and focus detecting circuit 12. 
The image sensor 11 receives two images respectively formed with the 
mirrors 6 and 7, and the lenses 8 and 9. The detecting circuit 12 
determines the distance up to the object by detecting the correlation of 
the positions of the two images based upon the scanning signal 
representing the two images from the image sensor 11. By comparing the 
obtained digital distance data with the digital data concerning the 
position of the focusing lens obtained from the brush 20, the focusing 
state of the automatic focusing lens 3 is detected. U.S. patent 
application Ser. No. 121,690 (filed on Feb. 15, 1980) now U.S. Pat. No. 
4,329,033 discloses such a circuit arrangement. 
Below the VTR V will be explained in accordance with FIG. 1 and FIG. 2. 
FIG. 2 shows an engaging mechanism of FIG. 1 in section, whereby members 
having the same figures as those in FIG. 1 are the same members. Further, 
the arrangement of the distance measuring device S at the side of the 
camera C is shown differently from FIG. 1 in order to show the internal 
arrangement. FIG. 2 shows a tape cassette 21, above which a loading ring 
22 and a guide drum 23 are arranged. The loading ring 22 is connected to 
the motor via a gear group 24, 25, 26. The coupling 14 at the side of VTR 
to be connected to the coupler 13 at the side of the camera, is engaged 
with a gear 28 via a gear 27. In the state shown in FIG. 2, the tape in 
the cassette has not yet begun to be loaded and the feeding reel 29 and 
the winding reel 30 of the cassette 21 are coaxially arranged, wherein the 
tape 35 is tensioned between the reels by means of the tape guide pins 31, 
32, 33 and 34. In the front wall 21a of the casing of the cassette 21 an 
opening 21b is formed, whereby the tape 35 is arranged at the opening 21b 
by means of a guide pins 32 and 33 in such a manner that the recording 
plane of the tape 35 faces the opening 21b. On the front of the lower 
plate (not shown in the drawing) of the casing of the cassette 21, a 
certain determined notch leading to the above opening 21b is formed in 
such a manner that when the cassette 21 is loaded, tape pulling out guides 
36 and 37 provided on the loading ring 22 are positioned inside of the 
tape 35 extending within opening 21b. 
The loading ring 22, which is driven as explained later, pulls out the tape 
35 from the cassette 21 and brings it over a predetermined range of the 
circumference of the guide drum 23. 
The guide drum 23 has a central axis inclined to that of the loading ring 
22 and a recording magnetic head (not shown in the drawing) inside the 
guide drum. Thus, along with the rotation of the magnetic head, the image 
signal is recorded on the tape. 
In the present specification, the operation of pulling out the tape 35 from 
the cassette 21 and bringing it on the circumference of the guide drum 23 
is called loading, while the operation of removing the tape 35 from the 
guide drum 23 and placing the tape 35 into the state before, loading is 
called unloading. 
On the circumference of the loading ring 22, concave portions 22a and 22b 
are arranged so as to correspond to a loading finish position and an 
unloading finish position respectively, while a driving gear part 22c is 
provided over the upper edge of the circumference. The driving gear 22c 
engages the gear 24 supported on a pin 24a provided on the chassis (not 
shown in the drawing). In the non-operative state shown in FIG. 2, the 
gear 24 is also engaged with the change over gear 25. The gear 25 is 
rotatably supported by pin 25a at one end of an L-shaped power change over 
lever 38 which pivots on pin 26a provided on the chassis. 
The change over lever 38 is urged by means of a spring 39 along the 
counterclockwise direction, whereby its rotation along that direction is 
prevented by means of a pin 41 on a loading finish detecting lever 40, and 
a pin 43 on a slide plate 42. Further, the pin 26a which supports the 
change over lever 38 also supports a gear 26. This gear is normally in the 
engaged state with the gears 25 and 44. The gear 44 is fixed on the 
rotating shaft of the DC motor M so as to be rotated by the motor M. 
Consequently, the rotation of the motor M is always transmitted to the 
change over gear 25 mounted at one end of the change over lever 38. 
The loading end detecting lever 40 is rotatably supported on a pin 40a 
provided on the chassis. The detecting lever 40 is urged by means of a 
spring 45 along the counterclockwise direction, whereby the end of a right 
arm 40b is positioned so as to be always in contact with the circumference 
of the loading ring 22. The end of the other arm 41c of the detecting 
lever 40 is in contact with a loading finish detecting switch S2, keeping 
the switch S2 in the switched off state when the VTR is non-operative as 
shown in FIG. 2. 
The slide plate 42 is movable within a certain determined range along the 
direction of arrows A and B in the drawing, by means of positioning pins 
extending in long holes in the plate 42, and is normally urged by means of 
a spring 46 along the direction of arrow B. The slide plate 42 is 
operatively engaged with a recording button (not shown) at the side of the 
VTR so as to be moved against the strength of the spring 46 along the 
direction of the arrow A when the recording button is depressed. An 
operation piece 42a is formed on the slide plate 42 so as to bring a 
recording mode detecting micro switch S1 in the closed state when the 
slide plate 42 is moved in the direction of the arrow A along with the 
depression of the recording button. Further, at a predetermined position 
in the neighborhood of the upper end of the slide plate 42, a worm wheel 
27 is arranged. The worm wheel 27 is rotatably supported by a pin 27a and 
engages the worm gear 28 integral with the coupling 14 at the side of the 
VTR on the camera bottom. 
Further, in the neighborhood of the circumference of the above loading ring 
22, an unloading finish detecting lever 47 is arranged. The lever 47 is 
rotatably supported by a pin 47a, being urged by a spring 48 along the 
counter-clockwise direction. One end 47b of the lever 47 is normally in 
contact with the circumference of the loading ring 22 under the strength 
of the spring 48, and is set into the concave portion 22b formed in the 
circumference of the loading ring 22 so as to correspond to an unloading 
finish in the non-operative state of the VTR shown in FIG. 2. The other 
end 47c of the lever 47 operates an unloading finish detecting switch S3, 
which is closed in this state. 
The terminal group t1 at the side of the camera C, and the group t2 at the 
side of the VTR V are the terminal groups connecting the camera C and the 
VTR for controlling the loading motor M. FIG. 3 shows the driving circuit 
of the loading motor M. In FIG. 3, at the side of the VTR V, are 
respectively a recording mode detecting switch S1, a loading finish 
detecting switch S2 and an unloading finish detecting switch S3, whose 
output levels are high in the closed state and low in the opened state. 
The output of the above switch S1 is connected to an input of an AND 
circuit AND 1, and inverted by an inverter INV 1 and delivered to the AND 
circuit AND 2. The output S2 is inverted by an inverter INV 2 and 
delivered to the AND circuit AND 1 and to the camera C via terminal groups 
t1 and t2. Further, the output of the unloading finish detecting switch S3 
is inverted by an inverter INV 3 and delivered to the AND circuit AND 2. 
The AND circuits AND 1 and AND 2 are respectively connected to the bases 
of switching transistors T1 and T2 for driving relays R1 and R2 via 
resistors r1 and r2 through OR circuits OR1 and OR2 in the next stage. 
The collectors of the transistors T1 and T2 are connected to a DC power 
source Vcc through the exciting coils of the relays R1 and R2 
respectively, and the emitters are grounded. The relays R1 and R2 serve to 
drive the motor M and control the direction of the rotation, whereby the 
terminals Ma and Mb of the motor M are respectively connected to the fixed 
terminals R1a and R2a of the relays R1 and R2. In the stationary state the 
fixed terminals R1a and R2a of the relays R1 and R2 are connected to the 
change over terminals R1b and R2b, while when the current is supplied to 
the exciting coils the fixed terminals R1a and R2a are respectively 
connected to the change over terminals R1c and R2c. As is shown in the 
drawing, R1b and R1c are respectively connected to R2b and R2c. 
With of the above-mentioned motor control circuit at the side of the VTR, 
and in the non-operative state shown in FIG. 2, when the recording button 
(not shown) is depressed, the slide plate 42 is moved along the direction 
of the arrow A in operative engagement. Thus, the switch S1 is closed, 
whereby the level of its output changes out of low into high. Because at 
this time, the loading finish detecting switch S2 is in the opened state 
and the level of its output is low, the level of the output of the AND 
circuit AND 1 becomes high so that the level of the output of the OR 
circuit OR1 changes out of low into high. Thus, the transistor T1 is 
brought into the closed state and the current runs through the exciting 
coil of the relay R1. Consequently, the fixed terminal R1a of the relay R1 
is connected to the change over terminal R1c, whereby the DC motor is 
connected to the DC power source. That is, the motor starts to run. The 
rotation of the motor M is transmitted to the loading ring 22 via the 
gears 44, 26, 25 and 24 so as to start to rotate the ring 22 along the 
direction of the arrow C. Along with the rotation of the loading ring 22, 
the tape 35 is pulled out of the cassette 21 by means of the pull out pins 
36 and 37, and brought around the circumference of the guide drum. At the 
same time, the unloading finish detecting lever 47 is urged out of the 
concave portion 22b, whereby the switch S3 is opened. Thus, as is shown in 
FIG. 4, the loading ring 22 rotates by a predetermined angle and the tape 
35 is wound over the guide drum about over 180.degree.. When the tape has 
been loaded, the arm 40b of the loading finish detecting lever 40 is urged 
into the concave portion 22a formed in the circumference of the ring 22, 
whereby the detecting lever 40 is rotated around the pin 40a by means of 
the strength of the spring 45 along the counterclockwise direction. 
Along with rotation of the detecting lever 40, the power transmission lever 
38 whose rotation is prevented by the engaging pin 41, is rotated along 
the counterclockwise direction, whereby the change over gear 25 is 
disengaged from the gear 24 and engaged with worm wheel 27. Accordingly, 
rotation is not transmitted to the loading ring 22 but to the automatic 
focusing mechanism driving gears 27 and 28. 
Since the loading finish detecting lever 40 is engaged in the concave 
portion 22a, the loading finish detecting switch S2 is closed and the 
level of the output of the AND circuit AND 1 becomes low. At this time, 
the level of the output of the OR circuit OR1 changes out of high into low 
so as to bring the transistor T1 in the opened state. As a result the 
fixed terminal R1a of the relay R1 is connected to the change over 
terminal R1b so as to interrupt the current supply to the motor M, which 
stops running. 
Further, when the arm 40b of the loading finish detecting lever 40 is 
engaged in the concave portion 22a in the circumference of the loading 
ring 22, the ring 22 is locked at the loading finish position. When 
sufficient locking cannot be obtained only from the engagement of the arm 
40b in the concave portion 22a, a separate lock means (not shown) is 
provided so that at the same time with the loading finish, the loading 
finish ring 22 is locked at the loading finish position. When the tape 35 
has been loaded as is shown in FIG. 4, the device is ready for recording. 
Thereafter, the tape is driven in a conventional way, the recording 
circuit operates and a recording operation is carried out. 
When an automatic focusing lens operation button (not shown) at the side of 
the camera C is operated, the AF switch S4 in FIG. 3 operates, and because 
the loading finish detecting switch S2 in FIG. 3 is closed, the AND 
circuit AND 3 is in an operative state and the focus detecting circuit 12 
is brought in the operative state. The circuit 12 detects the focus 
adjustment state of the automatic focusing lens 3, namely in focus, near 
focus or far focus and delivers the instruction signal to flip-flops FF1 
and FF2 as to whether the rotor is driven forwards or backwards. FF1 is 
the flip-flop for controlling forward running and its level is high when 
the lens is near focus. The flip-flop is reset with an in focus signal. 
FF2 is the flip-flop for controlling backward running and its level is 
high when the lens is far focus. The flip-flop is reset with the in focus 
signal. 
The above instruction signal is delivered to the OR circuits OR1 and OR2 
through the terminal groups t1 and t2 connecting the camera to the VTR, so 
as to drive the motor M forwards or backwards. Further as is shown in FIG. 
4, in this state the mechanical engaging mechanism of the motor M is 
disengaged from the loading side but engaged with the worm wheel 27 so as 
to transmit the rotation of the motor to the lens driving mechanism for 
the automatic focus control at the side of the camera, namely the couplers 
14 and 13, and the gears 15, 16 and 17 through the worm gears 27 and 28. 
Below, the unloading operation will be explained. In order to start the 
unloading operation after the recording finish, the recording button is 
taken out of the depressed state, whereby the slide plate 42 is moved 
along the direction of the arrow B by means of the strength of the spring 
46. As the result, the power transmission change over lever 38 which is 
engaged with the engaging pin 43 on the slide plate 42, is rotated against 
the strength of the spring 39 along the clockwise direction in such a 
manner that the gear 25 is disengaged from the worm wheel 27 and engaged 
with the gear 24. At the same time, along with the movement of the slide 
plate 42 along the direction of the arrow B the switch S1 is opened. 
Namely, the level of the output of the switch S1 becomes low, and because 
the unloading finish detecting switch S3 is opened and the level of its 
output is low, the level of the outputs of the AND circuit AND 2 is high. 
As the result the level of the output of the OR circuit OR2 becomes high 
and the transistor T2 is brought in the closed state. Consequently, the 
relay R2 is excited and the motor M starts to rotate. Because in this case 
the current runs from the terminal Mb through the motor M to the terminal 
Ma, the motor rotates along the other direction than at the time of the 
loading. Thus, the rotation of the motor M is transmitted to the loading 
ring 22 via the gears 44, 26, 25 and 24 so as to rotate the loading ring 
22 along the reversed direction of the arrow C, in such a manner that the 
loading finish detecting lever 40 is taken out of engagement in the 
concave portion 22a and the switch S2 is opened. When the loading ring 22 
resumes the state before the loading in FIG. 2, the unloading finish 
detecting lever 47 engages the concave portion 22b in the loading ring 22 
and the switch S3 is closed. As the result, the level of the output P3 of 
the switch S3 becomes high, and the level of the output of the AND circuit 
AND 2 becomes low. Thus, the level of the output of the OR circuit OR2 is 
low and the transistor T2 is brought in the opened state so that the motor 
M stops running. Namely, the unloading is finished and the non-operative 
state in FIG. 2 is again assumed. 
As mentioned above, the video system in accordance with the present 
invention includes the video camera for obtaining the image signal and the 
video recorder for recording the obtained image signal in such a manner 
that the driving power of the video recorder is transmitted to the video 
camera so as to drive movable parts of the video camera. Consequently, it 
is not necessary to provide the video camera the compact video camera can 
easily be realized. Especially in the case of a video recorder in which 
the image signal is recorded on a tape shaped recording medium, the 
driving power not needed for loading the tape during recording is 
transmitted from the loading motor to the camera, so that one motor can be 
used in common. Even when an automatic focusing adjusting mechanism is 
arranged on the video camera, the driving power is obtained from the side 
of the VTR so that there is no danger that the system becomes too large, 
and a video system which is quite handy and easy to carry then can be 
offered to potential users. 
The present invention is not limited to the present embodiment but can be 
varied in many ways within the scope of the claims.