JPS60194676A - Video camera - Google Patents

Abstract

PURPOSE:To obtain a small-sized, high-performance camera by installing suitably a crystal filter in an optical path in proper position relation with simple components, and using an external light shield body organically in relation with the crystal filter. CONSTITUTION:A lens barrel part 1 has a flange 2 on its outer peripheral surface almost in its lengthwise center. This flange 2 constitutes part of the wall constituting a camera body 3 to form the principal structure of the video camera body 3. A main lens 5 arranged in the lens barrel part 1 is positioned at the front side of a solid-state image pickup element 6 and an optical image is formed on the solid-state image pickup element 6. Further, the crystal filter 15 for reducing moire characteristic to the solid-state image pickup element 6 is arranged in the optical path of the optical system. This crystal filter 15 needs to be placed at right angles to the optical axis. Further, when the external light shield body 20 is incorporated in the circular opening 27 of a frame 25, the projection 29 of the external light shield body is engaged with the cut 28 of the circular opening 27 to inhibit the light shield body 20 from rotating around the optical axis.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a video camera, and particularly to a video camera that forms an optical image of a subject in front on a solid-state image sensor through a lens disposed in a lens barrel. This invention relates to a video camera that converts into electrical signals and extracts them.

[Background of the invention W4 and Part 1 In a video camera that uses a solid-state image sensor,
Usually, a crystal filter is installed in the optical path of the optical system to reduce specific moiré (false signals due to interference fringes).

This invention allows this crystal filter to be installed in its optical path in a simple manner, and also organically uses an external light shield to prevent light from entering the optical path from the outside. Its main purpose is to provide video cameras.

A mounting flange is removably attached to the rear end portion of the lens barrel of the video camera according to the present invention. The solid-state image sensor is attached to this attachment flange via screws. Further, a spring is arranged between the solid-state image sensor and the mounting flange. The crystal filter is fitted into a hole formed approximately in the center of a filter mounting plate which is disposed between a mounting flange and a spring so as not to rotate about the optical axis. Further, the optical path from the crystal filter to the solid-state image sensor is covered with an external light shield to prevent light from entering from the outside. This external light shield is made of an elastic body, and its front part is in contact with the crystal filter, and its rear part is in contact with the solid-state IIl image element. This prevents the crystal filter from coming off the hole in the filter mounting plate.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

[Embodiment of the Invention] FIG. 1 is a side sectional view showing an embodiment of the invention. FIG. 2 is a view taken along the line ■-■ in FIG.

Further, FIG. 3 is an exploded perspective view showing the structure of the crystal filter mounting portion, which is a feature of the present invention.

Mainly referring to FIG. 1, a lens barrel section 1 has a flange 2 on an outer circumferential surface of a substantially central portion in its length direction. This flange 2 constitutes a part of the wall constituting the camera body 3, and constitutes the main structure of the video camera body 3. Forming such a flange 2 on the outer peripheral surface of the central portion of the lens barrel 1 is advantageous for the following reasons. That is, with such a configuration, the rear part of the lens barrel 1 is housed within the camera body 3, and as a result,
This is because it gives a compact appearance. Further, by installing, for example, a circuit board in the space on the outer peripheral surface of the rear portion of the lens barrel 1, the space can be used effectively, so that the entire video camera can be downsized.

Further, as shown in the figure, in the front part of the lens ll1rR section 1, a front lens 4 has a distance scale displayed on the outer peripheral surface.
is installed. Last time, lens 4 was lens 1! The front lens 4 is engaged with the body part 1 by a screw, and therefore, by rotating the front lens 4, the front lens 4 is moved in the optical axis direction. In this way, the front lens 4 adjusts the focus depending on the subject.

A main lens 5 disposed within the lens barrel 1 is positioned in front of the solid-state image sensor 6 and forms an optical image on the solid-state image sensor 6.

The solid-state image sensor 6 is fixed onto the main substrate 7 by, for example, soldering. The main board 7 has screws 9 attached to a mounting flange 8 which is removably attached to the rear end portion of the lens barrel 1.
Mounted via. The number of screws 9 is, for example, three, and they are preferably located at equal intervals. A spring 10 is arranged around the screw 9, whereby the main board 7 is always biased in a direction away from the mounting flange 8, and presses the head of the screw 9 in the same direction.

Therefore, even if there is some play between the screw 9 and the female thread that receives this screw 9, the main board 7 will not be able to connect to the mounting flange 8
accurately positioned against. The position of the solid-state Ml image element 6 is thus adjusted by adjusting the screw 9 accordingly. Here, the positional adjustment of the solid-state image sensor 6 means the adjustment of the perpendicularity to the optical axis and the adjustment of the distance between the lens 5 and the solid-state image sensor 6.

The mounting flange 8 is detachably attached to the rear end portion of the lens barrel 1. Specifically, the mounting flange 8 has an inner diameter hole 11 configured to receive the outer circumferential surface of the rear end portion of the lens barrel portion 1 . Therefore, the mounting flange 8 is allowed to slide on the outer circumferential surface of the rear end portion of the lens barrel portion 1 . Then, if the mounting flange 8 is slid further rearward from the state shown in the figure,
It is removed from the rear end of the lens barrel 1 together with the main board 7. Further, forward sliding of the mounting flange 8 is prohibited because the front end of the mounting flange 8 comes into contact with a stepped portion 12 formed in the lens barrel section 1 . This state is the state shown in FIG. In this way, the mounting flange 8
The position W1 in the optical axis direction with respect to the lens barrel 1 is as follows:
It is defined by bringing these into contact. Then, in this state, if the mounting screw 13 that is provided to penetrate from the outer surface of the mounting flange 8 to the inner diameter hole 11 is screwed in, the tip of the mounting screw 13 will press against the outer peripheral surface of the lens barrel 1. By doing so, the lens barrel portion 1 of the mounting flange 8
The position relative to is fixed.

Further, the mounting flange 8 is provided with a rotation inhibiting portion 14 for inhibiting rotation of the mounting flange 8 on the lens barrel portion 1.
is provided. The rotation inhibiting portion 14 is, for example, a recessed portion that engages with a projection 14a that is integrally formed on the outer peripheral surface of the lens barrel portion 1. Alternatively, it is configured by a combination of a keyway and a key, and the rotation of the mounting flange 8 with respect to the lens barrel 1 during assembly (the rotation of the mounting flange 8 with respect to the lens barrel 1)
(rotation around the optical axis passing through) is prohibited. In this way, if the mounting flange 8 is prevented from rotating at a predetermined position, the lens Il'i11 and the solid-state image sensor 6
The rotational direction around the optical axis is maintained appropriately.

In the illustrated video camera, a crystal filter 15 is disposed within the optical path of the optical system in order to reduce moiré (false signals due to interference fringes) specific to the solid-state image sensor 6. This crystal filter 15 needs to be darkened perpendicularly to the optical axis, and furthermore, its mounting direction needs to be regulated in order to exhibit a crystal orientation with good optical characteristics with respect to interference fringes. Therefore, preferably the following configuration is adopted. 1 and 3, the crystal filter 15 has an almost cylindrical shape as a whole, as shown in the figures, but in order to clarify the direction when assembling, Both ends are machined into a straight line. This crystal filter 15 is fitted into a hole 17 provided approximately at the center of a filter mounting plate 16 disposed between the mounting flange 8 and the spring 10. The three mounting holes 18 formed in the filter mounting plate 16 are for inserting the screws 9 used for mounting the main board 7. When the filter mounting plate '16 is sandwiched between the mounting flange 8 and the spring 10, the filter mounting plate 16 is adapted to maintain proper perpendicularity to the optical axis. In addition, the hole 17 of the filter mounting plate 16
has a shape corresponding to the shape of the crystal filter 15.

Further, as shown in the figure, a protrusion 19 is formed in the hole 17, thereby inhibiting forward movement of the crystal filter 15. Thus, when the crystal filter 15 is fitted into the hole 17 of the filter mounting plate 16, the crystal filter 15 maintains a proper perpendicularity to the optical axis. Furthermore, since rotation about the optical axis is also prohibited, an appropriate mounting direction can be selected.

Further, as shown in FIGS. 1 and 3, the optical path from the crystal filter 15 to the solid-state image sensor 6 is covered with an external light shield 20 to prevent light from entering from the outside. . Since the solid-state image sensor 6 has a low signal current density, it dislikes external noise, and particularly when noise (for example, electromagnetic waves) mixes into the charging conversion surface, unpleasant screen unevenness occurs.

Therefore, the external light shield 20 is preferably made of conductive rubber, which can be obtained, for example, by incorporating a conductive substance into silicone rubber.

The external light shield 20 is made of an elastic body, and
As shown in the figure, it has a rectangular recess (D cut) 21 on its rear end face that engages with the solid-state image sensor 6, and its front end face engages with the outer diameter of the crystal filter 15. It has a recessed portion 22. Therefore, in the external light shielding body 2o, the crystal filter 15 is connected to the filter mounting plate 16.
so that it does not come off from the hole 17 of the crystal filter 1.
It also has the function of prohibiting rotation of the lens 5 around the optical axis. Further, the external light shielding body 2o preferably has a skirt portion 23 at its front portion, which surrounds the outer peripheral portion of the crystal filter 15 and whose tip is in contact with the filter mounting plate 16. This nuka-1 part 2
3, the external light shield 20 and the crystal filter 1
5, and the light is completely blocked.

Further, the external light shielding body 20 is formed with a cushion portion or a notch 24 for absorbing expansion and contraction in the optical axis direction. The existence of this cushion portion 24 provides the following advantages. That is, solid wi! As described above, the IIs element 6 is assembled and adjusted by adjusting the screw 9, but its mounting position in the optical axis direction differs slightly depending on the optical characteristics. In that case, the error can be absorbed by the cushion portion 24, so that an appropriate pressing force can always be applied to the crystal filter 15.

In the preferred embodiment shown, the frame 25 is fixedly attached to the flange 2 of the lens barrel 1 . The frame 25 is made of a sheet metal such as a plated iron plate or an aluminum plate and has a U-shaped cross section, and preferably has a substantially L-shaped overall shape.

Both open ends of the frame 25 are fixed to the flange 2 via screws 26, respectively. In this way, the camera body 3 as a whole constitutes a lightweight and strong structure.

As shown in FIG. 3, the frame 25 includes an external light shield 2
It has a circular opening 27 for receiving 0. A notch 28 is formed in the circular opening 27 as shown in the figure. Correspondingly, the external light shield 20 has a protrusion 29 that engages with the notch 28, as can be seen in FIG. 4, in which a portion of its rear portion is removed. The projection 29 and the notch 28 constitute a rotation inhibiting means for inhibiting the rotation of the external light shielding body 20. That is, when the external light shielding body 20 is assembled into the circular opening 27 of the frame 25, the external light shielding body 20 is assembled by engaging the protrusion 29 of the external light shielding body and the notch 28 of the circular opening 27.
Prohibits rotation around the optical axis.

[Effects of the Invention] As described above, according to the present invention, it is possible to install a crystal filter in the optical path while maintaining an appropriate amount of W111$9 in the optical path with very simple components and with very simple work. 1 can be done. Further, since an external light shielding body is used in conjunction with the crystal filter, a compact and high-performance video camera can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing one embodiment of the present invention. FIG. 2 is a view taken along the sub-section (■-■) of FIG. 1. , FIG. 3 is an exploded perspective view showing the structure of the crystal filter mounting portion, which is a feature of the present invention. , 144 is a perspective view with a part of the rear end portion of the external light shield removed. In the figure, 1 is a lens barrel, 6 is a solid-state image sensor, and 8 is a solid-state image sensor.
is a mounting flange, 9 is a screw, 10 is a spring, 15 is a crystal filter, 16 is a filter mounting plate, 20 is an external light shield,
23 is a skirt portion, 28 is a notch, and 29 is a projection. Agent Masuo Oiwa

Claims (3)

[Claims] (1) An optical image of the subject in front is formed mainly by a solid-state image sensor through a lens placed inside the lens barrel,
In a video camera that converts this into an electrical signal and extracts it, and further includes a crystal filter disposed in the optical path of the optical system for reducing moiré, the rear end of the lens barrel. A mounting flange is removably attached to the part, and the solid-state imaging device is attached to the mounting flange via a screw, and its position is adjusted by adjusting the screw, * A flap is arranged between the element and the mounting flange so that the solid mII! The element is always urged in a direction away from the mounting flange, and the optical axis of the crystal filter is set in a hole provided approximately at the center of a filter mounting plate that is disposed between the mounting flange and the spring. The optical path from the crystal filter to the solid-state image sensor is fitted so as not to rotate around the center.
In order to prevent light from entering from the outside, it is covered with an external light shield, and the external light shield is made of an elastic body, and its front part abuts the crystal filter and its rear part contacts the crystal filter. A video camera, characterized in that the crystal filter is brought into contact with a solid-state image carrier, thereby preventing the crystal filter from coming out of the hole of the filter mounting plate. (2) The front part of the external light shielding body is provided with a skirt part that surrounds the outer periphery of the crystal filter and whose tip is in contact with the filter mounting plate.
A video camera according to claim 1. (3) The video camera according to claim 1 or 2, wherein the external light shielding member is prohibited from rotating about the optical axis by a rotation inhibiting means.