JPH04182615A - Optical image forming device - Google Patents

Abstract

PURPOSE:To obtain an optical image forming device whose accuracy is improved, whose constitution is simple and whose handleability is excellent by separating an objective lens to a first objective lens on an object side and a second objective lens on an image side, providing a first lens movement device, forming the image of the object at the focusing position of the second objective lens or disposing a screen. CONSTITUTION:The second objective lens 14, a projection screen 17c, mirrors 17a and 17b which guide light from the lens 14 to the screen 17c, a cross-movable placing table 12 or the like are integrally provided on a main body part 11. A turret member 16 is fitted so that it can be moved up and down with respect to the main body 11 and driven by motor operation or manual operation. The first objective lens 13 is fitted and fixed to the member 16. The screen 17c is adjusted and aligned with a focal surface on the back side of the lens 14. In the case that the image of the surface of object to be inspected 18 is formed on the screen 17c, the member 16 is driven so as to align the focal surface on the front side of the lens 13 including lenses 13a and 13d with the surface of the object to be inspected. The light from the focal surface on the front side of the lens 13 forms the image of the object on the focal surface on the front side of the lens 13 on the focal surface on the back side of the lens 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical image forming apparatus that forms an object image using an objective lens.

[Conventional technology]

An example of an optical image forming apparatus is a projection inspection apparatus. Among these projection inspection apparatuses, an example of a type in which the optical axis is vertically directed upward is shown in FIG. 6, which is the most common type and has the highest occupation rate. A member 62a that fixedly supports a cross moving stage 62 is moved up and down by a guide 62b provided between the support member 62a and the main body 61 and a drive device (not shown) with respect to the main body 61 placed on a desk (not shown). It is movable and focuses on the surface of the object.

In addition, recently, screens with relatively small diameters have been introduced, so that they can be used with large stage, as shown in the example in Fig. 7.
A guide 71c and a guide 71c are provided between the dark box 71b and the main body 71a in order to focus the dark box (head part) 71b of the system including the projection lens 73 on the image side by driving it with respect to the main body 71a. Some are equipped with a drive device (not shown).

Further, as another example of the optical image forming apparatus, an example of a measuring microscope for use on a boat is shown in FIG. An intermediate member 81a connected to an L-shaped main body 81 to which a cross moving stage 82 is fixed is movable by a guide 81c such as a dovetail, and is coarsely moved over a long distance. A member 81b (observation section) including an objective lens and a system on the image side thereof is movable by a guide 81d using a linear hair ring or the like, and is finely moved in a small stroke. Of course, there are some that do not have fine movement feed.

Both the projection inspection equipment and measurement microscope mentioned above require performance not found in other optical systems, such as extremely high magnification accuracy, so the objective lens itself and the systems on the image side must be strictly It has been adjusted to have a solid structure,
Focusing was performed by relatively moving the object to be examined and the system after the objective lens so that the optical path length was constant and the object surface to be examined coincided with the optical object plane.

[Problem to be solved by the invention]

The projection inspection device shown in Fig. 6 above supports the cross-moving stage with a movable guide, so when the stage is to be enlarged to meet the recent needs for expanding the measurement range, it is necessary to In order to cope with the increase in weight, the weight of the test object, the movement of the center of gravity of the movable part caused by cross movement, etc., the mechanical burden to ensure the rigidity of the guide part increases.

Therefore, it is necessary to increase the size of the device and increase the driving force, and it becomes difficult to ensure accuracy.

On the other hand, in the head vertical movement system shown in Fig. 7, which has recently been seen for large-scale workpieces, the moving part is a structure (head) that does not change the load or center of gravity, so the workpiece is inherently Although it is easy to bring out the accuracy possessed by the projector, it cannot be used if it is used with a model with a relatively small diameter screen because it requires movement of the large diameter screen and large capacity dark box part unique to projection investigation instruments.

Models with large diameter screens have no advantage because the load on the head itself becomes too large. In addition, the head movement method moves the projection screen as well, so
There is a problem in that the observer's eye level must also be moved depending on the object to be examined. When measuring by applying a scale or the like to the screen, external force from humans is also applied, so the guide requires sufficient rigidity to include this, which is still a heavy burden.

Furthermore, an example of a measuring microscope is similar to the latter method, in which the stage is fixed and the observation section is movable (FIG. 8).

In the case of such a measuring microscope, the observation section is smaller and lighter than the head section of a projection inspection device, so there is less mechanical burden and it is advantageous for ensuring accuracy. However, compared to observing through a projection screen, when looking through an eyepiece, the height of the eyes must be strictly determined.If the object is to be examined with a large difference in level, the eyepiece position will move up and down, making it difficult to maintain a constant observation posture. It has the problem of poor performance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and provide an optical image forming device that has a simple configuration without impairing usability and that can ensure sufficient accuracy even when used as various inspection devices. do.

[Means to solve problems]

The present invention as set forth in claim (1) is characterized in that the objective lens is separated into a first objective lens on the object side and a second objective lens on the image side, and the first objective lens is moved in the optical axis direction for focus adjustment. The optical image forming apparatus is characterized in that a moving lens moving device is provided to form an object image at the focal position of the second objective lens.

Further, the present invention according to claim (2) is the optical image forming apparatus according to claim (1), characterized in that a screen is disposed at a focal position of the second objective lens. And so.

Furthermore, the present invention as set forth in claim (3) provides an optical image forming apparatus as set forth in claim (1), further comprising: an optical image forming apparatus as set forth in claim (1), further comprising: a close-limit lens for observing the object image; did.

[Operation] With the above configuration, the only member that moves for focus adjustment is the first objective lens on the object side.

Therefore, it is necessary to move the stage up and down to adjust the focus.
Since there is no need to integrally move the components after the objective lens up and down, the configuration is simple, and the position of the observed image does not change up and down, improving usability.

Further, according to the present invention as set forth in claim 2.3, since an object image can be obtained on the screen simply by moving the first objective lens, the moving member can be made small and lightweight, and the moving member can be free from load fluctuations. Since there is no movement of the center of gravity, it is relatively easy to simplify the mechanical structure, increase rigidity, and improve accuracy.

Furthermore, since only a portion of the objective lens moves to adjust the focus, the eyepoint remains constant, allowing observation at a constant position regardless of the height of the object, improving work efficiency.

〔Example〕

FIG. 1 shows a first embodiment in which the present invention is applied to a projection inspection device. The main body portion 11 is integrally provided with a second objective lens 14, a projection screen 17c, mirrors 17a and 17b for guiding light from the second objective lens 14 to the projection screen 17c, a cross moving stage 12, and the like. The turret member 16 is connected to the main body 11 as a linear guide 16 including rollers and bearings.
It is mounted so as to be movable up and down via a, and is driven with respect to the main body 11 via a feed screw or the like, either electrically or manually. The first objective lens 13 is attached and fixed to the turret member 16. With this configuration, the projection screen 17c is the second
It is adjusted and coincides with the back focal plane of the objective lens 14. To focus on an arbitrary object surface 18 (that is, to form an image of the object surface 18 on the projection screen 17c)
, the first objective lens 13 including lenses 13a and 13d may be driven so that its front focal plane coincides with the object surface.

As a result, the light from the front focal plane of the first objective lens 13 becomes parallel after passing through the objective lens 13, and the object at the front focal plane of the first objective lens 13 appears on the rear focal plane of the second objective lens 14. Form an image.

In this case, basically only the first objective lens 13 needs to be driven, but in practice, a variable magnification mechanism and a reflective illumination device are required. In the embodiment shown in FIG. 1, the first objective lens (projection lens)
From an external light source device 15d, a hollow hole 16C formed in the central axis of the turret mount 16b, which can be rotated and switched.
Illumination light is introduced using an optical fiber 15c, and is transmitted to the first
It passes through the half mirror 13b built in the auxiliary condenser lens 13C1 of the objective lens 13, and then the first objective lens front group 1.
A vertical epi-illumination device is illustrated that illuminates the object surface 18 through 3a. A configuration using a built-in half mirror for epi-illumination is known from Japanese Patent Publication No. 61-53804, and can utilize conventional know-how such as flare reduction. In addition, by using optical fiber 15c,
It can prevent the influence of heat from the light source. Light is introduced through the central axis of the turret mount 16b, so that the member 16 does not have any protruding parts and the weight burden is reduced compared to the case where a light source section is attached to the turret member 16. Of course, the turret mount may be a single mount, and the epi-illumination may also be structured such that a conventional light source is attached to the member 16.

Note that FIG. 2 shows the mirrors 17a and 17b in the embodiment shown in FIG.
By changing the arrangement and orientation of the screen, the height of the screen can be suppressed. That is, mirror 17
The light reflected by the mirror 17b is reflected in the same height direction so as to change its direction toward the front of the page, and the light is reflected by the mirror 17a.
, 17b, the projection screen 17 is located at approximately the same height as the projection screen 17b.
guided by c.

FIG. 3 shows a third embodiment. This does not have a loading table,
The head portion 31 is provided with a drive device for the first objective lens 13, and is suitable for use by being attached to a machine tool such as a die grinder, for example. The projection device itself has vertical movement (
Since it has a focusing device, there is no need to provide a special device for vertical movement on the mounting partner 32, and furthermore, the range of vertical movement can be greatly expanded compared to similar devices that have existed in the past. I can do it. This is one of the very effective application examples of the present invention.

FIG. 4 shows a fourth embodiment in which the present invention is applied to a measuring microscope. A main observation section (a second objective lens 44, a relay lens, an eyepiece, etc.) is provided on the main body 41, and a stage 42 is fixed thereto. Similar to the embodiment of the projection inspection device,
A member 46 to which the first objective lens 43 is attached is movable up and down relative to the main body 41 via a guide 46a using a ball race or the like, and a feed device using a rank, a pinion, etc. A circle 46b drawn with a two-dot chain line in the figure is a feed handle of the feed device.

FIG. 5 shows a fifth embodiment in which the present invention is applied to a measuring microscope, and is an example in which the present invention is applied to the fine movement guide side of a conventional measuring microscope that has two guides, coarse movement and fine movement. That is, the observation section 57 is guided so as to be vertically movable via the guide 57a with respect to the main body 5I to which the stage 42 is fixed, and the observation section 57 is moved up and down by rotation of the feed handle 57b of the feeding device.

This is a coarse movement. Coarse movement is used when the observation unit 57 is moved largely when the object 48 is high (the reverse may also be the case). Further, a member 56 holding the first objective lens 43 against the observation section 57 is guided by a guide 56a so as to be movable up and down, and the first objective lens 43 is moved up and down by rotation of the handle 56b of the feeding device. This becomes a slight tremor. Therefore, the position of the eyepoint does not change during slight movement.

In addition, the fine movement side handle 56b can be configured near the first objective lens 43, and when performing vertical movement operation (as long as the height of the test object 8 is determined, the coarse movement side handle 57b is not operated). Work that used to require reaching deep into the room becomes easier.

According to the above-described embodiments of the present invention, (1) The vertical moving part of the focusing barrel is lightweight and can be simply configured, and there is no change in load or center of gravity, which simplifies guidance;
Improved accuracy can be achieved. Since the load on the drive system is small, handling is improved when using a manual system, and low-output equipment is required when using an electric system. (2) The cost of the vertical movement mechanism can be reduced. (3) The eye level during observation can be improved. (4) The weight of the moving parts is small, improving reliability during transportation, (5) The same performance as before (magnification accuracy, resolution, etc.) is maintained. 6) If applied to height measurement, the degree of freedom in design is higher than in conventional configurations, so it is possible to reduce error factors in scale arrangement, etc.

Further, according to the embodiment shown in FIG. 1, optical fibers are used, and in order to take advantage of the features of the present invention, it is possible to eliminate the weight burden on the light source section and at the same time avoid the influence of heat from the light source lamp.

Further, according to the embodiment shown in FIG. 3, it is possible to provide a retrofit projection head which has a large vertical movement range and has good performance, and which can achieve its functions simply by attaching it.

Furthermore, according to FIGS. 4 and 5, it is possible to overcome the ``vertical movement of the eye point,'' which was a fundamental problem with measuring microscopes.

Furthermore, according to FIG. 5, since the vertical movement knob can be placed in the front, workability is good even in a model compatible with a large stage.

〔Effect of the invention〕

As described above, according to the present invention, the moving part for the goldfish is only the first objective lens, so the configuration is simple,
Moreover, since the stage and the observation position are fixed, it is easy to ensure accuracy and improve usability.

[Brief explanation of the drawing]

FIG. 1 is a schematic partial cross-sectional view of a first embodiment of the present invention in a projection tester, FIG. 2 is a schematic partial cross-sectional view of a second embodiment of the present invention in a projection tester, and FIG. FIG. 4 is a schematic partial cross-sectional view of the fourth embodiment of the present invention in a measuring microscope; FIG. 5 is a schematic partial cross-sectional view of the fifth embodiment of the present invention in a measuring microscope. Figure, 6th
The figure is a schematic partial sectional view of a conventional stage table top and bottom type projection inspection device, and FIG. 7 is a schematic partial sectional view of a conventional head top and bottom type projection inspection device.
FIG. 8 is a schematic partial sectional view of a conventional measuring microscope. [Explanation of symbols of main parts] 13.43...First objective (projection) lens 14.44.
・Second objective lens

Claims (3)

[Claims] (1) Separating the objective lens into a first objective lens on the object side and a second objective lens on the image side, and providing a lens moving device that moves the first objective lens in the optical axis direction for focus adjustment, An optical image forming apparatus characterized in that an object image is formed at a focal position of the second objective lens. (2) The optical image forming apparatus according to claim 1, further comprising a screen disposed at a focal position of the second objective lens. (3) The optical image forming apparatus according to claim (1), further comprising an eyepiece for observing the object image.