JPH0428038Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention is a diffraction grating mounting device for a spectrometer (b) Prior art When installing a diffraction grating, the inclination of the diffraction grating can be finely adjusted; In the case of diffraction grating replacement, high reproducibility of installation is required. Fine adjustment of the inclination of the diffraction grating is done by
In some cases, fine adjustment of the rotation around the y and z three axes can be used to increase the machining accuracy of each part and obtain the accuracy of the mounting position of the diffraction grating without fine adjustment, but in general, fine adjustment is possible. It is preferable.

There are two design philosophies for precision machines: kinematic design and machine tool design. Machine tool design uses the fitting of dovetails and dovetail grooves to create a structure that allows objects to move in a straight line.This structure has the characteristics of high strength and rigidity, but requires high-precision machining. There are disadvantages such as poor interchangeability of parts between the dovetail groove and the dovetail, increased weight, and difficulty in nimble movement. The concept of kinematic design is that an object has six degrees of freedom of movement (translation along three axes, rotation around three axes, six in total), and each time a constraint point is added to the object, the degree of freedom of movement is increased. Since the degree of freedom is reduced by one, the object is supported and constrained at the minimum necessary constraint points for the required movement. In the case of linear motion, the degree of freedom is one, so five constraint points are necessary and sufficient. Specifically, three legs A, B, and C with spherical tips are attached to the moving body, the base surface is finished flat and a straight V groove is provided, and two of the three legs are Put wires B and C into this V-groove, and place the remaining wire A on the surface of the base. In this case, the supporting points of the moving object are four points, one point at the tip of leg A, and two points each at the tips of legs B and C, making it 5 points in total, and the moving body is moving in a straight line. This is a necessary and sufficient constraint on the As expected from this example, according to the kinematic design, the accuracy of the movement is determined by the flatness of the base and the straightness of the V-groove.
There is no need for high-precision machining for mutual compatibility such as dovetail and dovetail grooves, and therefore even if the moving body is replaced with respect to the base, it will move reliably without rattling or applying excessive force. It is possible to reproduce position accuracy and position accuracy, and the structure is simple and lightweight. However, in terms of strength and rigidity, it is not comparable to structures designed using machine mechanisms.

Because the kinematically designed structure has the above-mentioned characteristics, it is often used in precision machines that do not apply a large load, and is also used in the mounting structure of diffraction gratings in spectrometers, where the mounting position can be finely adjusted. There is. FIG. 2 is one such conventional example. In this figure, G is a diffraction grating and H is a diffraction grating holder. The diffraction grating G is fixed to the holder H, and the grating G and the holder H are integrated and serve as a replaceable part. A holder H is mounted on the diffraction grating base B of the spectrometer in a kinematically designed structure in a position adjustable manner (kinematic mount). In this structure, the diffraction grating holder H can be adjusted around the y-axis and the z-axis with respect to the table B. Since the holder H is immovable with respect to the stand B after the position adjustment is completed, six restraining points between the stand B and the holder H are necessary and sufficient. Three screws 1, 2, and 3 pass through the holder H, and each screw has a spherical tip. The tip of the screw 1 fits into the pivot hole 1' of the base B, the tip of the screw 2 engages with the V-groove 2' of the base B, and the tip of the screw 3 contacts the flat surface of the base B. Since support by pivots allows rotation around three axes, it corresponds to restraint at three points, resulting in a total of six points of support, and the position of holder H relative to base B is fixed at one point. By turning the screw 1, adjustment around the z-axis is performed, and by turning the screw 3, adjustment around the y-axis is performed. This structure stabilizes the structure by attracting the holder H to the stand B by means of a spring. This is fine when the holder H is placed horizontally on the table B as shown in Figure 2, but if the structure shown in Figure 2 needs to be placed vertically, the replacement part, the diffraction If the weight of the integral part of the grid and holder H is large, the structural rigidity will be insufficient. That is, since the weight is supported by the contact between the slopes of the pivot hole 1' and the V-groove 2' and the tips of the screws 1 and 2, the spherical surfaces of the tips of the screws 1 and 2 and the pivot hole 1 are supported as shown in FIG. ', V
The contact with the slope of the groove 2' etc. deviates from the dotted line position of correct contact state to the solid line position of uneven contact, creating a gap e, which causes structural play and is susceptible to external vibrations etc. Become. If the force that attracts the holder H to the base B is increased in order to eliminate this gap, the force applied to the holder H will increase, causing distortion, resulting in the loss of the original value of the kinematic mount.

(c) Purpose The present invention aims to improve the drawbacks of the conventional kinematic mount diffraction grating holder described above, and to provide a diffraction grating holder mounting structure that has sufficient rigidity and does not lose reproducibility in mounting when replacing the holder. There is.

(D) Structure The present invention provides a diffraction grating mounting device for vertically holding the grating plane of a diffraction grating, in which a diffraction grating holder is provided with three legs, and the tip of one of the three legs is connected to at least the lower part that supports the holder. The surrounding wall surface is engaged with the horizontal V-groove formed in the vertical plane part of the protruding diffraction grating stand, and the tips of the other two legs
The upper and lower portions of the groove should be brought into contact with the vertical plane portion of the diffraction grating holder, and the weight of the diffraction grating holder should be supported by the contact in the direction of gravity between the lower outer circumferential surface of the holder and the upper surface of the lower peripheral wall surface of the diffraction grating holder. According to
The present invention relates to a diffraction grating mounting structure in which the weight of the holder does not act at all on the contact points of the tips of the three legs with the diffraction grating stand.

(E) Embodiment An embodiment of the present invention is shown in Figure 4 and below. In FIG. 4, B represents a diffraction grating stand, which corresponds to B in FIG. 2, and is rotated around a horizontal axis Z by a wavelength drive mechanism (not shown). H is a diffraction grating holder attached to the diffraction grating stand B so that its position can be adjusted, and corresponds to H in FIG. 2, and G is a diffraction grating attached to the holder H. Three legs 1, 2, and 3 are attached to the diffraction grating holder H. These legs are screws and are screwed into the holder H, and can be moved forward and backward by turning them. The tips of these legs 1, 2, and 3 are spherical, and the tip of leg 1 is engaged with a V groove 1'' parallel to the z-axis formed on the diffraction grating base B, and the other two legs The tips of 2 and 3 are brought into contact with the flat surface Bf of the stand B.The relationship between them is well expressed in the cross-sectional view of Fig. 5.As seen in Fig. 5, the holder H has a back surface 3 A stud bolt 4 is installed at this location, and this bolt passes through a hole Bh drilled in the base B. Compared to the outer diameter of the bolt 4, the hole Bh is sufficiently large and the relationship between the two is completely loose. A compression spring 5 is interposed between the head of the bolt 4 and the back surface of the base B, and the holder H is attracted toward the base B. With the above structure, the diffraction grating holder H is attached to the leg 1. The holder H is supported at four points in total: two points of contact between the base and the V-groove 1'', and two points of contact between the tips of the legs 2 and 3 and the flat part Bf of the table B. Two degrees of freedom remain: rotation around the line (perpendicular to the plane of the drawing in FIG. 4), ie, rotation around the x-axis and sliding in the z-axis direction as explained in FIG. Of these two degrees of freedom, the diffraction grating holder H
The degree of freedom of movement of the weight in the action direction is rotation around the x-axis, and in the conventional example, this degree of freedom is also used for legs 1,
It was supported by the tips of the 2nd and 3rd grade and the pivot hole or the slope of the V-groove. In the present invention, as shown in FIG. 5, the diffraction grating stand B is shaped like a tray with a peripheral wall Bw, and the diffraction grating holder H is loosely fitted inside this peripheral wall, as shown in FIG. A protrusion Hs extending approximately 120° in the circumferential direction on the lower circumference of the holder H
By protruding and bringing this protrusion Hs into contact with the inner surface of the peripheral wall Bw of the stand B, the total weight of the holder H is supported, and rotation around the x-axis and sliding in the z-axis direction are restrained. Furthermore, in order to ensure contact between the protrusion and the peripheral wall of the diffraction grating table, a presser member 6 is brought into contact with the top peripheral surface of the holder H, and the presser member 6 and the diffraction grating table B are brought into contact with each other.
A compression spring 7 is interposed between the holder H and the holder H. The holding member 6 has a screw 8, and by pulling this screw, the holding on the holder H can be released.

In the above configuration, the legs 2 and 3 are arranged along the y-axis orthogonal to the grating lines of the diffraction grating G,
By rotating the legs 1 and moving them forward and backward, the rotational position of the grating G around the y-axis is adjusted. Also leg 1
Since it is arranged on the z-axis, the rotational position of the grating G around the z-axis can be adjusted by moving the legs 2 and 3 back and forth.

In the above-mentioned embodiment, the receiving part that supports the weight of the diffraction grating holder H is in contact with the line between the inner surface of the peripheral wall Bw of the diffraction grating stand B and the circumferential protrusion on the lower periphery of the holder H in the drawing, but in reality is the point between the concave surface (inner surface of the peripheral wall Bw) and the convex surface (projection Hs) with a slightly smaller curvature than that, and satisfies the kinematic constraint conditions while supporting the weight of the holder H. It is V who does
Since the contact is not on an inclined surface such as a groove, but on a point perpendicular to the direction of action of the weight and has a small relative curvature, sufficient supporting force can be obtained even on a point contact.

(f) Effect As mentioned above, in the present invention, since the diffraction grating holder is supported by three legs, the reproducibility of mounting positioning is good, and the lateral weight of the diffraction grating holder does not act on the support part of the three legs. First, the lateral weight is supported separately, so this is especially effective when the diffraction grating support structure has high rigidity and the diffraction grating holder is mounted on the diffraction grating stand in a vertical or inclined plane. It's big.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the three axes for adjusting the mounting position of the diffraction grating, Fig. 2 is a perspective view of a conventional example, Fig. 3 is an enlarged sectional view of the main part of the conventional example, and Fig. 4 is an example of the present invention. FIG. 5 is a front view of the embodiment, and FIG. 5 is a longitudinal sectional side view of the embodiment. G... Diffraction grating, H... Diffraction grating holder, B...
...Diffraction grating stand, 1, 2, 3...legs.

Claims (1)

[Scope of utility model registration request] In a diffraction grating mounting device that holds the grating plane of a diffraction grating perpendicularly, three legs with spherical surfaces at their tips are attached to the diffraction grating holder, which fixes the diffraction grating, so that they can be adjusted forward and backward, and are located at the vertices of one triangle. , the tip of one of these three legs is engaged with a V-groove formed horizontally on the vertical surface of the diffraction grating stand that holds the diffraction grating holder on the vertical surface, and the tips of the other two legs are abutting the vertical surface portion of the diffraction grating stand above and below the V-groove, respectively;
A diffraction grating mounting device in which the lower outer circumferential surface of a diffraction grating holder is brought into contact with a lower circumferential wall surface protruding from the lower part of the diffraction grating stand, so that the weight of the grating holder is supported by the lower circumferential wall surface of the diffraction grating stand.