JPS646493Y2 - - Google Patents

Description

[Detailed description of the invention] Currently, an electronic camera has been proposed that converts an optical image obtained through a lens system as shown in Figure 1 into an electrical video signal, and records this video signal on a rotating magnetic sheet. has been done.

The present invention relates to an interchangeable lens with a built-in electronic shutter suitable for use in such electronic cameras.

An example in which the interchangeable lens with a built-in electronic shutter of the present invention is used in an electronic camera as shown in FIG. 1 will be explained below with reference to the drawings.

In Figure 1, 1 is a built-in video signal forming circuit that converts an optical image obtained through a lens system into an electrical video signal, a rotating magnetic sheet recording device that records this video signal on a rotating magnetic sheet, etc. This electronic camera body 1 is equipped with an interchangeable lens 2 with a built-in electronic shutter, and a shutter button 1a.
and a battery pack 3 are provided.

In the present invention, the electronic shutter built-in interchangeable lens 2 is constructed as shown in FIG. 2, for example.

In Figure 2, 3 is the lens barrel, and 4 is the interchangeable lens 2.
A mount 5 for attaching the camera to the electronic camera body 1 is a lens system attached to the lens barrel 3 of the interchangeable lens 2, and a diaphragm 6 is provided at a predetermined position of the lens system 5.

In this example, an electronic shutter 10 is provided adjacent to an aperture 6 provided in a lens system 5. This electronic shutter 10 is composed of, for example, a first polarizing plate 7, a ferroelectric ceramic (PLZT) 8, and a second polarizing plate 9. The electronic shutter 10 will now be further explained with reference to FIGS. 3 and 4.
The polarization direction of the first polarizing plate 7 is perpendicular to the plane of the paper, and the polarization direction of the second polarizing plate 9 is parallel to the plane of the paper. 8a and 8b are electrodes provided on PLZT8. When no high voltage is applied to the electrodes 8a and 8b, the orientation of the PLZT 8 does not change (see FIG. 3). At this time, the incident angle L that has passed through the lens system 5 is polarized in a direction perpendicular to the plane of the paper by passing through the first polarizing plate 7 and enters the PLZT 8 . This polarized light passes through the PLZT 8 without rotating its polarization direction. Furthermore, this polarized light cannot pass through the second polarizing plate 9 because it does not match the polarization direction of the second polarizing plate 9. That is, when no high voltage is applied to the electrodes 8a and 8b, the shutter 10 is closed.

Also, when applying a high voltage to the electrodes 8a and 8b,
PLZT8 forms a 90 degree twisted orientation (see Figure 4). At this time, the incident light L that has passed through the lens system 5
passes through the first polarizing plate 7 and is polarized in a direction perpendicular to the plane of the paper, and enters the PLZT 8. The polarization direction of the light along the 90 degree twisted orientation in the PLZT 8 is rotated by 90 degrees. The polarized light rotated by 90 degrees matches the polarization direction of the second polarizing plate 9 and therefore passes through the second polarizing plate 9. That is, when the high voltage E is applied to the electrodes 8a and 8b, the shutter 10 is opened.

In this electronic shutter 10, the case where the polarization directions of the first polarizing plate 7 and the second polarizing plate 9 are orthogonal has been described, but the polarization of the first and second polarizing plates 7 and 9 is They may be provided so that the directions match. In this case, the shutter 10 is closed when the high voltage E is applied to the PLZT8,
When no voltage is applied, the shutter 10 is open. This arrangement is not reasonable in terms of power consumption, as it consumes power all the time and only consumes power for a short period of time during photographing.

Further, a high voltage drive circuit 11 for generating a high voltage and controlling the electronic shutter 10 is molded into the lens barrel 3 of the interchangeable lens 2. In this case, a terminal 12 for obtaining the input voltage of the high voltage drive circuit 11 is provided on the mount 4. This high-voltage drive circuit 11 first converts a DC voltage of several volts inputted from the electronic camera body 1 through a terminal 12 into an AC voltage, boosts this AC voltage using a transformer, and further converts the boosted AC voltage into an AC voltage. It is designed to convert the voltage into a DC voltage of approximately 500 [V]. The reason why such a high-voltage drive circuit 11 is molded for each interchangeable lens 2 is because this high-voltage drive circuit 11 is a circuit that generates high voltage, so it may adversely affect the electronic circuits and video signals in the electronic camera body 1. It is preferable that the electronic shutter 10 is located as far away from the electronic camera body 1 as possible in order to avoid this problem.Also, by changing the characteristics of the high-voltage drive circuit 11 molded into each electronic shutter 10 provided in the interchangeable lens 2, This is to respond. In this way, the DC voltage from the electronic camera body 1 can be kept constant without changing for each interchangeable lens 2.

According to this configuration, the shutter button 1 is now
When a is pressed, the incident light L enters the electronic shutter 10 via the lens system 5 and the aperture 6. At this time, the high voltage drive circuit 11 is operated by the voltage inputted from the electronic camera body 1 through the terminal 12, and a high voltage is applied to the electronic shutter 10, so that the electronic shutter 10 is operated. The incident light L passes through the electronic shutter 10 and enters the electronic camera body 1 via the lens system 5 on the electronic camera body 1 side. After a predetermined period of time has elapsed, the voltage is no longer input to the high voltage drive circuit 11 from the electronic camera body 1 via the terminal 12, so the electronic shutter 1
No high voltage is applied to 0. Therefore, the incident light L that has passed through the lens system 5 and the aperture 6 is blocked by the electronic shutter 10 and does not enter the electronic camera body 1.

As described above, according to the present invention, an interchangeable lens with a built-in electronic shutter can be obtained. Further, since the present invention uses an electronic shutter 10, it has the advantage of extremely fast response speed compared to conventional mechanical shutters. Further, according to the present invention, the high voltage drive circuit 11
is provided in the lens barrel 3 of the interchangeable lens 2, so that the high voltage caused by this does not adversely affect the electronic circuit and video signal in the electronic camera body 1, and the characteristics of each electronic shutter 10 provided in the interchangeable lens 2 can be adjusted. Since the difference can be dealt with by changing the characteristics of the high voltage drive circuit 11 provided for each,
The DC voltage from the electronic camera body 1 is transferred to the interchangeable lens 2.
It can be kept constant without changing every time. Further, in the present invention, since the high voltage drive circuit 11 is provided within the lens barrel 3, the direct current voltage supplied from the electronic camera body 1 can be a very low voltage of several volts, which provides good benefits.

In the above-described embodiment, the electronic shutter 10 is arranged adjacent to the aperture 6 of the interchangeable lens 2, but it is of course possible to arrange it at another predetermined position in the lens system 5. Furthermore, it goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations may be adopted without departing from the gist of the present invention.

[Brief explanation of drawings]

Fig. 1 is a front view showing an electronic camera, Fig. 2 is a partially cutaway sectional view showing an embodiment of an interchangeable lens with a built-in electronic shutter according to the present invention, and Figs. 3 and 4 show an electronic shutter and its FIG. 3 is a schematic diagram showing a drive circuit. 1 is an electronic camera body, 2 is an interchangeable lens, 3 is a lens barrel, 5 is a lens system, 6 is an aperture, 10 is an electronic shutter, 11 is a high voltage drive circuit, and 12 is a terminal.

Claims (1)

[Scope of utility model registration request] In an interchangeable lens with a built-in electronic shutter, in which a lens system is disposed within a lens barrel that can be freely attached to and removed from the camera body, an electronic shutter made of a polarizing plate and a ferroelectric material is provided at a predetermined position on the optical path within the lens barrel; , a high-voltage drive circuit for supplying a high voltage to the ferroelectric material of the electronic shutter is provided integrally with the lens barrel within the lens barrel by molding, and a terminal for an input voltage signal of the high-voltage drive circuit is connected to the mirror. An interchangeable lens with a built-in electronic shutter, characterized in that the lens is exposed from a mount on a body, and a low voltage signal is supplied to the terminal from the camera body side.