JPS58202432A - Motor-driven zooming device - Google Patents

Abstract

PURPOSE:To prevent waste power consumption, by providing a detecting means for detecting the fact that an element moving at the time of zooming reaches a stop position of the end or its vicinity, and stopping a motor by its detecting signal. CONSTITUTION:In a motor-driven zooming device which can execute zooming by a motor, when a zoom ring 2 turns and reaches the telephoto end or the wide end, a sliding piece 16 is connected to a telephoto end resistance R1 connected to an electric power source terminal Vcc or a wide end resistance R2 from a ground terminal G of a switching plate 17 fitted to a fixed barrel 3, and voltage appears in a detecting end V0. This voltage is used as a detecting signal, and when the zooming movement reaches the telephoto end or the wide end, it is utilized for stopping automatically the motor or executing an alarm display.

Description

[Detailed description of the invention] This invention relates to an improvement of an electric zoom device capable of

Conventionally, electric zoom devices have been employed in cine cameras, video cameras, and the like. In these electric zoom devices, the photographer has to judge whether the zooming mechanism has reached the end position of the zooming movement based on changes in the subject image seen through the TTL7 viewfinder or T-child viewfinder. For this reason, even if a friction clutch is provided between the electric mechanism and the zooming mechanism to prevent extreme stress from being applied to the electric mechanism or the zooming mechanism, the motor will stop working at the telephoto or wide end of zooming. The drive stop is delayed, which wastes power and reduces the durability of parts. Furthermore, there is also known an electric zoom device in which a control lever is attached to a zoom ring that rotates with each zoom so that zooming can also be performed manually. However, it is difficult to expect the photographer looking through the viewfinder to make a judgment based on this. In order to perform manual operation in this manner, it is necessary to provide a friction clutch between the electric mechanism and the zooming mechanism.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an electric zoom device that can clearly detect when zooming has reached the telephoto end or the wide end, regardless of changes in the subject image in the finder. be.

The electric zoom device of the present invention is equipped with a detection means for detecting that an element moving during zooming has reached an end stop position or its vicinity, and the electric zoom device according to the present invention is equipped with a detection means for detecting that an element moving during zooming has reached an end stop position or the vicinity thereof, and the electric zoom device uses a signal from this detection means to directly or Since motor drive can be indirectly stopped, unnecessary power consumption is prevented.
The durability of parts can be improved.

Hereinafter, the present invention will be explained based on the drawings.

Fig. 1 is a partial sectional view of a lens of a video camera equipped with an electric zoom device, Fig. 2 is a motor drive circuit diagram of the electric mechanism, and Figs. 3 to 6 are examples of installation of various detection means. 7 to 1/A are partial plan views or partial front views showing examples of various detection means, FIGS. 12 to 1D, and 76. Figure, No. 17
The figures are graphs showing the output signals of various detection means, and Fig. 1S is the graph showing the output signals of various detection means. PYJ and a circuit diagram of the detection means shown in Fig. 1θ, Fig. 11 is a block circuit diagram for controlling the drive of the motor and display of the stand based on the output signal of the detection means, and Fig. 19 is a circuit diagram of the cam groove of the zooming mechanism and FIG. 2 is a partially developed plan view of FIG. 1 showing a guide groove.

The zoom lens shown in Fig. 1 consists of a focus lens group F with a focus ring 7K[t, a front group lens V/and a rear group lens V for variable power that are moved in the optical axis direction by a zoom ring, and a fixed barrel. It is composed of a front lens group M for imaging and a rear lens group ml' which are integrally fitted into the lens 3, and the focus lens group F is set by rotating the focus ring l around the optical axis. Focusing is performed by moving back and forth in the optical axis direction, and the front group lens V/and rear group lens V for variable magnification
, 2, the cam pins 6 and 7 installed in the respective lens frames 6 and 7 rotate around the optical axis integrally with the zoom ring. By engaging with the optical axis direction guide grooves 3a and 3b provided in 3, when the zoom ring rotates around the optical axis, the cam ring 1 is performed. In addition, the focus ring
The cam ring L is screwed together with a helicoid screw K by a helicoid screw K, which is integrally connected to the fixed cylinder 3. When engaged with A and K, focusing and magnification are performed as described above.

The structure of a zoom lens as described above is conventionally known.

Furthermore, a zoom gear /I is rotatably mounted on the zoom ring 2, and a friction spring 12 is engaged therebetween so as to transmit the same force. This zoom gear //
The installation on the fixed cylinder 3 is reduced by 9 W! Forward and reverse rotation motor 1
The drive gears provided on the output shaft of No. 3 are in mesh with each other. Therefore, the rotation of the zoom ring is performed by the rotation of the motor 130 being transmitted to the zoom ring by the drive gear 1, the zoom gear meshing therewith, and the friction gear 12. The zoom ring 2 can also be rotated by operating a manual operation lever tS installed therein. In that case, the friction spring 12 and the zoom ring -0 or the zoom gear 1/ will not slip. Therefore, the rotation of the zoom ring controller is not transmitted to the motor/3K. In addition, the motor 13
Even when rotating by , the end of the cam groove of the cam ring l is connected to the lens frame. At the telephoto end or wide end where the cam pin 4.7 is reached, the friction spring 12 and the zoom gear // or the zoom ring slip, thereby preventing excessive force from being applied to the transmission system.

The motor 130 rotations are performed by the circuit shown in FIG. That is, when the selector switch S is turned on to the tele terminal '1'llK, the transistors Tr/ and Tr/' become conductive, and the motor 1
3, current flows from right to left, which causes motor/3
rotates the zoom ring to the telephoto side through the drive wheel/1 etc. When the selector switch S is turned on to the wide terminal W side, the transistors Trλ and Tr2' become conductive, and a current flows through the motor 13 from left to right. Rotate.

When zooming is performed using a motor in this way, the motorized zoom device of the present invention is designed to be fully equipped as shown in Figure 3, so that the rotation of the motor can be quickly stopped when the zoom reaches the wide end. A detection means as shown in FIG. 77 is provided.

FIG. 3 shows an example in which the sliding changeover switch type detection means shown in FIG. 7 or the potentiometer type detection means shown in FIG. When the ringco rotates and reaches the tele end or wide end, the slider 16 attached to it will connect the power from the ground terminal G of the switch plate 17 attached to the fixed yMJ if it is the switch type shown in Fig. 7. Since it is connected to the tele end resistor R/or the wide end resistor R2 connected to the terminal VCC, a voltage appears at the detection end Vo as shown in No. 1 1':A, and as shown in FIG. In the case of the potentiometer type, the slider /7 contacts the conductor part connected to the tele end side or wide end side of the sliding resistance R8 of the resistance plate /I attached to the fixed body 3, and the detection IA Vo K is A changed voltage appears as shown in FIG. In the potentiometer-type detection means shown in Fig. 1, the voltage at the detection end vO is different between the telephoto end and the wide end, so it is easy to distinguish between the telephoto end and the wide end, and it is also easy to distinguish between the telephoto end and the wide end. Since the voltage at the detection end VO changes continuously even during the speed being performed, it is also possible to use it for displaying or setting the magnification ratio. Also, in the switch type detection means shown in Fig. 7, if the resistance values of the resistors R/ and R2 are changed and the resistance value of the connecting resistor for detecting the voltage at the detection terminal vo is appropriately reduced, it is possible to Since the voltage values appearing on the side and wide end sides can be changed, it is also possible to easily distinguish between the telephoto end and the wide end.

The detection means shown in Fig. 1 is provided with a Hall element 19 on the fixed body 3, iron pieces 〃, 〃' on the zoom ring co, and a zoom ring λ.
It is provided at the position shown in the developed plan view of Fig. 9 so that it moves simultaneously to the telephoto end side and the wide end side and comes to the position of the Hall element 19, respectively. When the output vh of element /9 changes as shown in FIG. 1, it can be detected that the zooming has reached the telephoto end or the wide end.

The detection means in FIG. 5 is integrally attached to the fixed ring 43. A light emitting element I such as an LED is attached to the fixed ring 3', and a position opposite to the light emitting element is placed on the fixed barrel 3 across the wall of the zoom ring. A light receiving element 22 such as a photodiode or a phototransistor is attached to the zoom ring-0, and 6n and n' on the tele end side and wide end side are attached to the wall separating the zoom ring-0 light emitting element 1 and the light receiving element n, as shown in the partial front view of Fig. 1O. It consists of a configuration as shown in the diagram.

The first block shows the change in voltage Vc on the collector side accompanying zooming movement when a phototransistor as shown in Fig. 1S is used as the light receiving element n. Alternatively, it is possible to detect whether the wide end has been reached. It goes without saying that similar detection can be made when a photodiode is used as the light receiving element n.

The detection means in FIG. 6 is provided with a switch on the fixed barrel 3, and has a protrusion B that acts on the switch S when the zoom ring JK moves simultaneously toward the telephoto end and the wide end.

B' is provided as shown in Fig. 1/, and when the zoom ring reaches the telephoto end and the wide end, the base voltage b of the switch 2da becomes the power supply 11Il+V as shown in Fig. 17.
It changes from cc to ground voltage.

Figures 12 to 11 detected by the above detection means
The voltages shown in Figure 1 and Figure 17 are as follows when the zooming movement reaches the tele end or wide end.
It is used to automatically stop the motor 13 shown in the figure or to display a warning, and this is done by the circuit shown in FIG. 11. That is, at the first I'tA, the selector switch S of the drive circuit shown in FIG.
When the circuit is turned on and current starts to flow from the power supply Vcc, the II extension circuit activates the detection and output circuit of the above-mentioned detection means after a certain period of time has elapsed, and the detection circuit outputs a detected voltage. Let's do it. Here, the delay circuit delays a certain amount of time. When the zoom ring λ is initially at the telephoto end f11 or the wide end side, it is the time it takes for the zoom ring λ to come off that end. can be moved by motor drive from the telephoto end or wide end side, and determines whether the zooming movement has reached the telephoto end or wide end depending on whether the voltage is high or low, and when it reaches the telephoto end or wide gsK. In this case, a warning is displayed by stopping the motor 13 of the drive circuit or lighting up an LED.

In this way, when the zooming movement reaches the telephoto end or the wide end, the motor 13 can be stopped automatically or stopped immediately based on a warning display, so that the zoom lens shown in FIG. In order to allow the zoom ring λ to rotate beyond the magnification adjustment range, the cam grooves Ih and rb of the cam ring l and the zoom ring rotation guide groove JCK% of the fixed barrel 3 are formed in a circle as shown in FIG. 19. A circumferential extension may be provided. Therefore, in electric zooming, the stopper provided on the zoom lens;
Since the motor 13 is stopped before reaching the zero end, it is possible to achieve the effect that the vibration and vibration when stopping at the tele end or wide end are greatly reduced.

As described above, according to the present invention, unnecessary driving of the motor is prevented, power consumption is saved, wear and tear on parts is reduced, and shock and vibration can also be prevented. This excellent effect can be obtained.

[Brief Description of the Drawings] Fig. 1 is a partial sectional view of a lens of a video camera equipped with an electric zoom device, Fig. 2 is a motor drive circuit diagram of the electric mechanism, and Figs. 3 to 3 show various detection means. FIG. 7 is a partial schematic diagram showing an installation example; FIG. 7 to FIG. 1/FIG. Figure 1f and 1st. <Figure, No. 17
The figure is a graph showing the output signals of various detection means.
Figure I is a block circuit diagram for controlling motor drive and warning display based on the output signal of the detection means, and Figure 79 is a partially developed plan view of Figure 7 showing the cam groove and guide groove of the zooming mechanism. /...Focus ring, F...Focus lens group, λ...Zoom ring, ■l...Front group lens for variable power, Vλ...Rear group lens for variable power, 3...Fixed Torso, 3
'...fixing ring, M/...front group lens for imaging, Xco...rear group lens for imaging, 4(, j...lens frame, Otsu, 7...cam bin, j ... cam ring, 9 ... helicoid ring, 10 ... connection bottle,
//...Zoom gear, 12...Friction spring, 1
3...Motor, Lji...Drive gear, /S
...Manual operation lever, S...changeover switch, Tr
/, Tr/', Trλ, Tr2' -) transistor, 16...Slider, 17...Switching plate, G...Ground terminal, Vcc...Power terminal,
R/...Tele end viewing resistance, R2...Wide end resistance, VO...Detection end, /I...Resistance plate, R
6...Sliding resistance, 19...Hall element,〃
, 〃′... Iron piece, 1... Light emitting element, 〃・
...Photodetector, n, n'...hole, 2 holes...
Switch, B, 2f'...protrusion. Patent applicant Konishiroku Photo Industry Co., Ltd. - Nobu 91

Claims (1)

[Claims] t. An electric zoom device capable of performing zooming by a motor, comprising a detection means for detecting when an element moving during zooming has reached an end stop position or the vicinity thereof. An electric zoom device characterized by: 1. The electric zoom device according to claim 1, wherein driving of the motor is stopped by a signal from the detection means. & The electric zoom device according to claim 1 or 2, wherein a warning display is performed in response to a negative signal from the detection means.