JPS5934284B2 - Prism block mounting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for attaching a prism block that is useful for use in, for example, an image pickup tube type camera for separating brightness signals of a color television, a three image pickup tube type camera, a color film feeder, etc. In particular, the present invention relates to a prism block mounting device that allows prisms to be mounted easily, quickly, and with high precision.

In this type of device, as shown in FIG. 1, light incident on a camera lens 1 is incident on a prism 2a, and then two types of nonmetallic substances with different refractive indexes [for example, zinc sulfide (ZnS) and fluoride] are used. Magnesium fluoride ((HgF2), or titanium oxide (TiO2) and magnesium fluoride (MgF2)
2)] is separated into two optical paths by a dichroic mirror 3 formed by alternately vacuum-depositing an odd number of layers on the surface of an optical glass. It is formed so as to be guided to an image pickup tube 4 and an image pickup tube 5 for color signals.

By the way, in the case of these devices, if the mounting position of the spectroscopic prism block 2 on the camera body is shifted from the position shown by the solid line to the position shown by the broken line, for example, the light incident on the lens 1 of the camera The light is reflected by the prism 2a and guided in the direction of arrow A in FIG.

As a result, a situation has arisen in which light is guided to a position shifted from the center position of the image pickup tube 4 disposed at a predetermined position.
Therefore, the mounting position of the spectroscopic prism block 2 is as follows.
It must be installed at a predetermined position in a relative relationship with the imaging tube 4 and lens 1 that receive the light reflected by the prism 2a. Conventionally, from this point of view, as a method of attaching a spectroscopic prism to a predetermined position, a method as shown in FIGS. 2A and 2B has been used. That is, first, place a positioning pin T in the center of the camera support 6 on which the spectroscopic prism block is attached, and then place another positioning pin 8 on the line between the positioning pin T and the center position of the image pickup tube 4, respectively, on the prism base. Provided with 9.

Next, the overlapping surface of the first and second spectroscopic prisms 2a and 2b of the spectroscopic prism block 2, that is, the spectroscopic surface 10 that separates the incident light in a predetermined direction, is aligned with the center point of the positioning pin T. Then, based on that position, adjust the relative angle between the spectral plane 10 and the other positioning pin 8,
For example, the prism block 2 is attached to the upper surface of the prism stand 9 using adhesive or the like.

Note that 11 is a screw for fixing the prism stand 9 to the support body 6. However, according to the conventional prism block installation method in which the prism block is installed in a fixed position based on the installation position of one or two positioning pins, the center of the positioning pin and the prism block are must be precisely aligned with the spectral planes of the spectral planes.

If these do not match each other, the relative positions of the lens and the spectral plane of the prism block will shift, which will cause a center shift with respect to the image pickup tube. Therefore, the prism block must be reattached to the proper position, which requires time and effort, and it is not possible to reliably attach the prism block. The present invention has been devised in view of these conventional drawbacks.

That is, the present invention proposes a prism block mounting device that allows the prism block to be mounted easily and quickly in a proper position.

An embodiment of the present invention will be described below based on the drawings. Third
Figures A and 3B show a preferred embodiment of a spectroscopic prism block to which the present invention is applied, and Figure 4 shows its prism block.

In these figures, reference numeral 12 denotes a support provided inside, for example, an image pickup tube type color TV camera or a color film image feeder for separating luminance signals;
A plate-shaped prism stand 13 is fixed to the prism holder 13 by fixing means such as screws 14.

Reference numeral 15 denotes a pin that serves as a positioning protrusion that serves as a reference for attaching the spectroscopic prism block to a fixed position, and is inserted into the through holes 16 and 17 formed in the center of the support 12 and the prism stand 13, respectively. The head 18
protrudes slightly above the prism stand 13.

This positioning pin 15 is provided so as to be located at a point where the center lines of image pickup tubes for luminance signals and color signals, for example, intersect, similar to the above-mentioned image pickup tubes. Ten thousand,
Reference numeral 19 denotes a spectroscopic prism block, which is formed by first and second prisms 19a and 19b.

The mating surfaces of the first and second prisms 19a and 19b,
That is, a dichroic mirror 21 that selectively acts on color is provided on the spectral surface 20 that reflects and transmits the incident light from the lens. This dichroitsk
The mirror 21 is formed of, for example, multiple layers of zinc sulfide with a high refractive index and magnesium fluoride with a low refractive index, or cesium oxide and magnesifunium fluoride, etc., alternately formed on a glass surface.
It reflects light within a specific range of wavelengths, but transmits light at other wavelengths.

As shown in FIG. 4, the spectroscopic prism block 19 is formed in a shape that is different from each other with the spectral planes 20 of the first and second spectroscopic prisms 19a and 19b serving as boundaries.

The spectroscopy prism block 19 thus formed is placed on the prism stand 13, and the head 1 of the positioning pin 15 is placed on the spectroscopic surface 20 of the first prism 19a.
The outer circumferential surface 18a of No. 8 is brought into contact with the outer peripheral surface 18a. Note that the positioning pin 15 protruding from the top surface of the prism stand 13
As shown in FIG.
It is formed more quickly than 2.

A spectroscopy prism block mounting device of the present invention having such a configuration will be described below.

First, the prism stand 13 is fixed to the support body 12 via a plurality of screws 14 (four screws in the illustrated example). Then, the positioning pin 15 is fitted into each of the through holes 17 and 16 formed approximately at the center of the prism stand 13 and the support body 12 so that the head 18 protrudes above the prism stand 13. sticks to. Next, the spectroscopic prism block 1
9 to one of the prisms (in the illustrated example, the first prism 1
The prism is placed on the upper surface of the prism stand 13 with the outer circumferential surface 18a of the head 18 of the positioning pin 15 and the outer circumferential surface 22a of the head of the auxiliary positioning pin 22 in contact with the spectral surface 20 of 9a).

Note that, for example, an adhesive or the like is applied in advance to the upper surface of the prism stand 13, and the prism block 19 is fixed to the prism stand 13 using this adhesive or the like. In this way, the spectroscopic prism block 19 is attached to the outer peripheral surfaces 18a, 22a of the heads of the positioning pin 15 and the auxiliary positioning pin 22.
If the spectral surface 20 of one prism, that is, the prism 19a located on the lens side, is brought into contact with the lens, the positioning pins 15 and 22 function to mount the prism block 19 at a desired position on the prism stand 13. Therefore, the prism block 19 can be placed on the upper surface of the prism stand 13 mechanically and with high precision.

Therefore, the installation work of the prism block 19 can be carried out quickly. In addition, in the case of a prism block in which the dichroic mirror 21 is provided only in the vicinity of the center of the spectral plane 20, the outer peripheral surface 1 of the head of the two positioning pins 15, 22
The spectral plane 20 of the prism 19a disposed on the lens side at 8a and 22a is shown in FIG. 3 Al+! By making sliding contact in the X direction, it is possible to guide the incident light from the lens to the coverage area of the dichroic mirror 21.

In the above embodiment, in addition to the positioning pin 15, an auxiliary positioning pin 22 is provided, and by using this pair of positioning pins 15 and 22, the prism block 1
9 is attached at a fixed position, but it is not necessary to use an auxiliary positioning pin.

For example, the spectral surface 20 of the prism 19a may be brought into contact with the outer circumferential surface 18a of the head of the positioning pin 15, and the prism block 19 may be mounted at any desired angle using the pin 15 as a fulcrum. Further, in the above embodiment, an example was described in which a dichroic mirror was provided on the spectral surface of the prism, but the present invention is not limited to this, and the present invention can also be applied to a prism block in which a half mirror is provided on the spectral surface of the prism. It is possible.

Next, FIG. 5 shows a modification of the prism block, which is similar to the prism block of the above embodiment (see FIG. 4).
The difference is that a cut groove 24 is formed along the spectral plane 23 of the prism 19b, which is provided on the side opposite to the side where the lens is disposed, as a stepped portion to the extent that the head of the positioning pin does not come into contact with it. It is.

In the prism block 25 configured in this way, the spectral plane 20 of the prism 19a provided on the lens side on the outer peripheral surface of the head of the positioning pin is similar to the above-described prism block 19.
By bringing the prism block 2 into contact with the
Since the mounting position No. 5 is set, the mounting work can be simplified.

Next, FIGS. 6A to 6C show modified examples of the positioning pin, in which a positioning pin 27 is used in which half of the head is cut out from the center, thereby forming a notch 26. It is something that

With this configuration, the notch 2 of the positioning pin 27
By matching the side surface 26a of the prism block 6 with the spectral surface 20 of the prism 19a, the prism block 19 can be easily positioned. In the above embodiment, a positioning pin is attached to the prism stand and the prism block is mounted in a fixed position using the pin. However, the present invention is not limited to this. By forming the positioning pin, the same function as the positioning pin described above may be exerted.

As described above, the present invention includes placing a spectroscopy prism block consisting of a plurality of prisms combined so as to form a step in the spectral plane of each prism on a prism stand having a protrusion, and Since the spectral surface of one prism is brought into contact with the protrusion to determine the mounting position of the prism block, the mounting position of the prism block is mechanically set by the positioning pin and a special jig is used. Prism blocks can be installed easily, quickly and reliably without the need for tools.
Therefore, it is possible to easily reduce the positional deviation between the image pickup tube or the like provided on the reflective surface side of the prism and the reflected light of the prism.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram when the mounting position of the prism block is changed in an optical system using two image pickup tubes, Figure 2A
and FIG. 2B are a plan view and a partially cutaway front view showing a conventional prism block mounting device. FIG. 3 and subsequent figures show an embodiment of the present invention, and FIGS. 3A and 3B are a plan view and a partial cutaway showing an embodiment of a spectroscopic prism block mounting device to which the present invention is applied. 4 is a perspective view of the prism block used in the present invention as seen from the back side, FIG. 5 is a side view showing a modified example of the prism block, and FIGS. 6A and 6B are FIG. 6C is a front view and partially cutaway side view showing other embodiments of the present invention, and FIG. 6C is a perspective view showing a modification of the positioning pin used in FIGS. 6A and 6B. 12...Support, 13.
... Prism stand, 15, 27 ... Positioning pin, 18 ... Head of positioning pin, 19,
25... Prism block, 20... Prism spectral plane, 21... Ditaloic mirror 22... Auxiliary positioning pin, 24...
...kerf.

Claims (1)

[Claims] 1. A spectral prism block consisting of a plurality of prisms combined so as to form a step in the spectral plane of each prism is placed on a prism stand having a protrusion, and the spectral plane of one prism is placed on the protrusion of the prism stand. A mounting position of a prism block characterized in that the mounting position of the prism block is determined by bringing the prism blocks into contact with each other.