JPS59107310A - Zoom magnification detecting device - Google Patents

Abstract

PURPOSE:To obtain a titled device with high reliability by providing plural reflective type optical sensors for detecting a bit pattern of a reflecting part, on a fixed part opposed to a zoom lens rotating part, and synthesizing and fetching each output of these reflective type optical sensors. CONSTITUTION:A titled device is provided with a zoom lens rotating part 11 of a video camera, a reflecting part 12 installed to the outside circumference of the zoom lens rotating part 11, and reflective type optical sensors 13a, 13b and 13c provided on a fixed base part opposed to the zoom lens rotating part 11 so as to be opposed to bit patterns 12a, 12b and 12c, respectively, of this reflecting part 12. In this state, each output of these reflective type optical sensors 13a-13c is synthesized by a synthesizing circuit 14, and picked up between output terminals 15a, 15b.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a zoom magnification detection device used to change the directivity of, for example, a microphone in conjunction with the zoom magnification of a video camera.

Conventional Structure and Problems Generally, a video camera is equipped with a zoom lens, and a zoom magnification detection device is provided to change the directivity of a microphone in conjunction with the zoom magnification of the zoom lens. FIGS. 1 and 2 show a conventional zoom magnification detection device. In FIGS. 1 and 2, 1 is a zoom lens rotating section of a video camera, 2 is a film resistor section 3 provided on the outer periphery of the zoom lens rotating section 1, and is electrically connected to the film resistor section 3. a slider portion sa provided on the fixed base portion 6 facing the electrode portion 4 and the zoom lens rotation portion 1 and in contact with the film resistor portion 3 and the electrode portion 4;
, eb are constructed as variable resistors. As shown in FIG. 3, the variable resistor 2 has a power source 7 connected to one slider section 6a, and the other slider section 6
b is grounded via a fixed resistor 8 and connected to one output terminal 9. Note that 10 in the figure is the other output terminal. In such a zoom magnification detection device, the variable resistor 2 has a resistance value corresponding to the zoom rotation position, that is, the zoom magnification, and the reference voltage E is determined by the variable resistor 2 and an external fixed resistor 8. Voltage obtained by dividing■. As a result, the voltage corresponds to the zoom ratio. However, the zoom magnification detection device having such a configuration has low reliability because it uses a slider, and has the disadvantage that it is difficult to make appropriate corrections when changing the directivity of the microphone.

OBJECTS OF THE INVENTION An object of the present invention is to provide a zoom magnification detection device that can reliably obtain a signal linked to the lens magnification of a zoom lens.

Composition of the Invention The zoom magnification detection device of the present invention is configured to optically detect the rotational position of the zoom lens rotating section of a video camera and extract a signal corresponding to the zoom magnification.
This is to improve reliability.

DESCRIPTION OF EMBODIMENTS FIGS. 4 and 6 show an embodiment of the present invention.
In FIGS. 4 and 5, 11 is the zoom lens rotating section of the video camera, and 12 is the zoom lens rotating section 1.
Reflective parts attached to the outer periphery of 1, 13a, 13b
, 13c is the bit pattern 12a of the reflective section 12,
12b and 12c are reflective optical sensors provided on a fixed base (not shown) facing the zoom lens rotation unit 11, respectively. The respective outputs of the reflective optical sensors 13a to 13C are combined in a combining circuit 14 shown in FIG. 6, and taken out between output terminals 15a and 15b. Here, as shown in FIG.
C, and the reflective optical sensors 13a to 13C are connected to the reflective part 1 from the reflective optical sensors 13a to 13C.
The light is projected onto each of the two bit patterns 12a to 12G and the reflected light is received. Each of the reflective optical sensors 13a to 13b has a light emitting diode 13a-D, 1ab- as shown in FIG.
D.

13cmD and phototransistor 13a-Q, 13
b-Q.

13 cmQ, and the power supply voltage E is supplied.

The light emitting diodes 13a-D to 13cmD are grounded through resistors R1, R2, and R3, and the outputs of the phototransistors 13a-Q to 13C-Q are connected to dividing resistors R111R12, R211R22, and R3, respectively.
4, weighted by R32, resistor R131R231R3
3 and applied to the inverting input terminal of the operational amplifier 16, and the command voltage V is applied between the output terminals 1sa and 1esb. It is designed to take out. Incidentally, an integrating circuit consisting of a resistor R4 and a capacitor C is provided between the inverting input terminal and the output terminal of the operational amplifier 16, and the 3-bit patterns 12a to 12c are connected to each other.
Indicated voltage V at the time of change. It smooths out the changes in

In the zoom magnification detection device having such a configuration, the bit pattern 1 that can be detected at the position of the reflective optical sensors 13a to 13c at a specific lens rotation position, that is, at a specific zoom magnification.
Each of the bits 2a to 12c turns on the reflective optical sensor 13a to 13C corresponding to the bit when the reflecting portion is shown as a blank space in the drawing, and turns off when the reflecting portion is shown as a hatched portion. At this time, mainly dividing resistors R11 and R121R
21 and R221 Voltage indicating each bit weighted by R31 and R32 (staircase waveform shown by solid line in Figure 7)
is combined by resistors R13, R231 and R33, and is the instruction voltage V when the bit pattern changes. As a result, as shown in FIG. 7, the command voltage V corresponds to the zoom ratio. is obtained.

In the above embodiment, the command voltage (2) is linear with respect to the rotation angle of the zoom lens rotating section 11. I explained what was configured to take out the zoom magnification fingernail voltage■. When changing the directivity of a variable directional microphone using 1. It is necessary to perform auditory correction for changes in directivity with respect to zoom ratio. If it is necessary to perform such auditory correction, the bit patterns 12a, 12b, and 12c of the reflecting section 1203 attached to the outer periphery of the zoom lens rotating section 11 may be formed as shown in FIG. 8a. At this time, the voltage indicating each bit becomes a step-like waveform as shown in FIG.
Since 0 can have an arbitrary function, the auditory sensation can be easily corrected. Therefore, according to this embodiment, the instruction voltage for the lens rotation angle can be easily changed arbitrarily by the bit pattern arrangement.

Effects of the Invention As described in detail above, according to the present invention, the zoom lens rotating section of a video camera is provided with a reflecting section having a bit pattern linked to the lens rotation angle, and a plurality of reflecting sections are provided to detect the bit pattern of the reflecting section. A reflective optical sensor is installed on a fixed part facing the zoom lens rotating part, and the outputs of these reflective optical sensors are combined and output by a synthesis circuit, so that the rotational position of the zoom lens rotating part can be adjusted easily. It has the advantage of being able to optically detect and mechanically extract a signal corresponding to the zoom magnification in a non-contact manner, resulting in high reliability. Further, since the function of the command voltage can be changed arbitrarily by the bit pattern arrangement of the reflection section, there is an advantage that auditory sensation correction can be performed easily.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional zoom magnification detection device, Fig. 2 is a side view of the same device, and Fig. 3 is an electrical circuit wiring diagram of the device.
Fig. 4 is a front view showing one embodiment of the zoom magnification detection device of the present invention, Fig. 6 is a side view of the same device, Fig. 6 is an electrical circuit connection diagram of the device, and Fig. 7a is the same device. 7 is a diagram showing the output waveform of the same pattern. FIG. 8a is a diagram showing another example of the bit pattern arrangement of the reflective part of the same device. Figure 8 is a diagram showing the output waveform of the same pattern. 11...Zoom lens rotating section, 12...
・Reflection part, 12a, 12b, 12C...Bit pattern, 13a, 13b, 13c...=
= Reflective optical sensor, 14... Synthesis circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 4 Figure 5 Figure 2 ItJυ

Claims (2)

[Claims] (1) A reflective part with a bit pattern linked to the lens rotation angle is provided in the zoom lens rotation part of the video camera,
A plurality of reflective optical sensors that detect the bit pattern of this reflective part are connected to a fixed part 1 (facing the zoom lens rotating part).
A zoom magnification detection device configured to combine and output the sensor outputs of these reflective optical sensors in a combining circuit. (2) The zoom magnification detection device according to claim 1, wherein the synthesis circuit includes an integral element that smoothes changes in the command voltage when the bit pattern changes.