JPS58114012A - Optical picture processing system - Google Patents

Abstract

PURPOSE:To obtain a lightweight, easy-to-handle system and to use holography technique as practical measurement technique by sticking a glass block which has a vapor-deposited mirror surface to a recording material into a block. CONSTITUTION:Luminous flux (a) from an Ar laser is caused to illuminate a glass block on the opposite upper side from right and above. The 1st glass block 21 is a mere rectangular parallelepiped. Then, the luminous flux (a) illuminates such the 2nd glass block 22 that a triangular prism having a rectangular equilateral triangle base is set horizontally. The 3rd glass block 23 in a similar shape has a metallic vapor-deposited film of aluminum on a slanting surface. This vapor-deposited film corresponds to the 1st mirror 9. Surfaces of the 1st block 21, the 2nd block 22, the 3rd block 23- are adhered mutually. Thus, a glass block of adequate size in an adequate shape is formed and mirror surfaces are formed by vapor deposition, sputtering, etc., and bonded together into one small, lightweight block.

Description

[Detailed Description of the Invention] The present invention relates to an image processing optical system configuration method,
The details will be explained below using a holographic optical system as an example.

Holography divides coherent light into two parts, one
One irradiates the object, and the other directly enters the recording material. Because interference fringes between the object beam and reference beam are recorded on the material,
By applying a reference light, the original image of the object can be restored.

A half mirror is required to split the light into two.A mirror is required to reflect the light. Since interference fringes are created by differences in the optical path lengths of light rays, the optical path length and mirror angle must be strictly fixed. Moreover, it must not be affected by vibration.

For this reason, the holography device must be constructed on a heavy and wide surface plate. For example, the surface plate is vertically 15
00++++n, 700 rrm wide, several hundred meters thick, it is a block of iron that is elastically supported by springs, tires, etc.

The weight is around 100% or more. The heavier the weight, the higher the vibration cutoff frequency, and the more effective it is at removing vibrations.

Optical equipment such as lenses, mirrors, beam splitters, etc.
The laser, the object to be measured, etc. are all fixed on the surface plate. Optical equipment must be held strictly stationary on a surface plate using a magnetic stand or the like.

The principles of holography are well known, and the deformation of objects can be measured using holographic techniques. When an object deforms, the density and position of interference fringes created by the object beam and reference beam change, and this allows us to determine the degree of deformation.

However, these measurement methods are still limited to experimental studies in the laboratory. This is because a heavy surface plate is required, and the object to be measured must be fixed on this surface plate, so the scope of measurement is limited. Furthermore, it is impractical for the measuring device to be larger than the object to be measured.

The fact that there is still room for laboratory experiments applies not only to holography technology, but also to image processing optical systems in general, such as Fourier transform and correlation.

The present inventor has conducted various studies in order to make holography technology a practical measurement technology. In order to eliminate the wide and heavy surface plate, the mirrors and recording materials themselves must be small and must be able to maintain constant relative distances and angles, and the coherent light beam from the laser must be able to be transmitted without using many mirrors. that it must be guided to the desired position;
and 3. that the reconstructed holographic image can be easily observed.
I found that two requirements were essential.

In order to meet these requirements, the mirror, half mirror 1 recording material, etc. can be combined into one block, an optical fiber can be used to guide the laser beam, and an image fiber can be used to guide the laser beam. It is sufficient to transmit the reproduced image.

Furthermore, to measure the deformation of an object in real time, Bi+2Si02o (B SO
Therefore, it is sufficient to use a material having real-time characteristics such as BGO element) or Bi r2Geozo (BGO element).

The present invention is based on such an idea. The deformation measurement optical system based on the present invention combines a mirror and a recording material into one lump, and is made by gluing a glass block with a mirror surface deposited on it and the recording material into a lump. be.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure, operation, and effects of the present invention will be explained below with reference to drawings showing examples.

FIG. 1 is a configuration diagram showing an optical deformation measuring device including a deformation measuring optical system as an example of the present invention.

In this embodiment, an Ar (argon) laser 1 is used as a writing light source, and an 11e-Ne (11e-Ne) laser is used as a reading light source.
helium neon) laser 2 and TV (television) camera 3
and a television receiver 4, and a holographic deformation measurement optical system 5.The Ar laser 1 and the holographic deformation measurement optical system 5 are connected by a single mode fiber 6.He-Ne laser 2, 'I' V The camera 3 and the holographic deformation measurement optical system 5 are connected by a single mode fiber 7 and an image fiber 8, respectively.

FIG. 2 is a configuration diagram of the internal optical system of the holographic deformation measurement optical system.

The green coherent light emitted from the Ar laser 1 becomes a light flux that passes through the single mode fiber 6 and enters the first mirror 9 inside the holographic deformation measurement optical system.

The b light flux that has been reflected by the first mirror 9 and changed its course by 90 degrees is incident on the half mirror 10. The light is reflected here and is divided into a C light flux that heads toward the object to be measured O and a d light flux that passes through the No. 1-7 mirror 10 and goes straight.

The C light beam hits the object to be measured O fixed outside the holographic deformation measurement optical system 5. Here, the C light beam (object light) reflected by the object to be measured 0 travels straight through the nozzle mirror 10 .

The d light flux is reflected by the second mirror 11 and becomes an f light flux, which functions as a reference light.

That is, the C light beam, which is the object light, passes through the dichroic mirror 12 and enters the recording material 13.

The f light flux serving as the reference light is incident on the recording material 13 at an appropriate angle with the C light flux.

The recording material 13 is B112SiO2o crystal or Bit2
A real-time material such as GeO2° crystal (abbreviated as BSO element or BGO element) is used.

A DC voltage is applied to the BSO element and the like. When light enters this, it has photoconductivity, so the density of electrons changes depending on the interference fringes created by the object light and reference light. When there is no light irradiation, there are few transitions between localized levels (traps) of electrons, and the relaxation time is as long as 20 to 30 hours.

With the above steps, a hologram is generated on the recording material.

Reading is performed by a 1ie-Ne laser 2. This is because the wavelengths are different and the output is weak, so the recorded interference fringes will not be erased.

The coherent light emitted from the 1ie-Ne laser 2 becomes an l beam that passes through the single mode fiber 7, is reflected by the third mirror 14, changes its course, and becomes an h beam. h
The light beam is reflected by the fourth mirror 15 and becomes l light beam.

The light flux l enters the recording material 13 in the opposite direction to the reference light f from the Ar laser, and reads out the recorded image of the object to be measured 0. The reason that the l light flux and the l light flux are not strictly antiparallel is based on the difference in wavelength between the two lasers. The brightness ratio of the angle formed by the normal line to the recording material and the i and l beams is set to be equal to the wavelength ratio.

Upon receiving the reference light l beam, the recording material 13 produces l light beam. The l light flux is a light flux that produces a real image at the position of the object O to be measured. The guichroic mirror 12 transmits the light of the Ar laser, but reflects the light of the l-1e-Ne laser.

The l beam of light from the 11e-Ne laser is reflected by one dichroic mirror 12. The reflected light beam is reflected by the fifth mirror 16 and becomes a light beam. l
The light flux is transmitted through the image fiber 8 to the camera 3
image plane (not shown).

In order to measure the deformation of the object to be measured O, a double exposure method may be used in the arrangement shown in FIG.

That is, the state of the object O before deformation is irradiated with an Ar laser beam, and interference fringes caused by the object beam and the reference beam are recorded on the recording material 13.

After the object to be measured 0 is deformed, the Ar laser beam is irradiated once again to record the state of the object to be measured on the recording material.

The object to be measured O is recorded twice on the recording material 13. H
Passing the e-Ne laser beam through the single mode fiber 7,
When the light is reflected by the mirrors 14 and 15 and then applied to the recording material 13, a double real image is created at the position of the object O, as described above. These real images are almost identical, but since they are deformed, they become duplicated and there is interference between the two images, so the deformed mouse can be identified by the position and shape of the interference fringes.

The above measurement method is publicly known.

In the present invention, the mirror and recording material used here are constructed of glass blocks, etc., and the holographic deformation measuring optical system is made into one block. A feature of the present invention is that the holographic optical system is assembled into a single unit.

FIG. 3 is a perspective view showing an embodiment of the present invention, corresponding to the optical system configuration diagram in FIG. 2.

Most are made of clear glass. The light beams of the mirror and half mirror 1 are given the same reference numerals as in FIG.

This glass lump is made up of many glass blocks glued together.

The a beam from the Ar laser enters the glass block 21 on the opposite side from the upper right in FIG. 3. The first glass block 21 is a simple rectangular parallelepiped.

The light beam a then enters the @2 glass block 22 which is shaped like a horizontal triangular prism with a right isosceles triangle as its base.

A third glass block 23 having a similar shape has a metal vapor deposited film such as aluminum on its slope. This vapor deposited film corresponds to the first mirror 9.

First block 21, second block 22, third block 2
3, etc., the surfaces are bonded to each other with an adhesive.

The fourth glass block 24 and the fifth glass block 25 are similarly bonded to each other with the vapor deposited film sandwiched between them on diagonal surfaces. This vapor deposited film is also a part of the first mirror 9.

The light beam a is reflected twice by these mirror surfaces and reaches the half mirror 10 located at the middle of the lower front end.

The half mirror 10 is made by attaching a vapor-deposited film to the diagonal surfaces of two triangular prism glass blocks 26 and 27, each of which has a right isosceles triangle as its base.

The readout light from the He-Ne laser also enters the glass block from the upper right in FIG.

The eighth glass block 28 and the ninth glass block 29 are shaped like a rectangular parallelepiped cut with a slope.

l of the eighth glass block or the ninth glass block 29;
A vapor deposited film is provided at a location corresponding to the lJ cross section to reflect the g light flux and guide it to the recording material 13. The third mirror 14 in FIG.
This mirror also serves as the fourth mirror 15.

Now, the C light beam reflected by the half mirror 10 exits the glass block 26 and irradiates the object O to be measured.

The d light beam transmitted through the half mirror 10 is transmitted to the second mirror 11
It is reflected by the beam and enters the recording material 13 obliquely.

10th glass block 30 and 11th glass block 31
has a shape like a rectangular parallelepiped cut with a slope, and f'
L (7) 7' A vapor-deposited film was applied to the slope of the 0-piece to form a mirror, and then it was glued.

The dichroic mirror 12 is provided between a triangular prism-shaped twelfth glass block 32 in contact with the recording material 13 and a thirteenth glass block 33 shaped like a rectangular parallelepiped cut diagonally.

The dichroic mirror transmits Ar laser light and
Reflect mNe%. A mirror with selective permeability, 1'
i02. It can be obtained by vapor depositing an oxide such as CcOz or SiO.

Thereafter, in the same manner, a glass block of appropriate size and shape is made, a part of the mirror etc. is formed on it by vapor deposition, sputtering, etc., and this is adhered.

The glass lump shown in Figure 3 has approximate dimensions of 2αX 2
It is about cm x 5 cm, and the total iM is about 50 g. Small and light.

The deformation measurement method described above was based on a double exposure method. An Ar laser was used for writing, and a He-Ne laser was used for reading.

Next, phase conjugate bolography will be described below as an application example of the present invention.

FIG. 4 is a schematic diagram showing an example of the use of phase conjugate holography.

The light from the Ar laser 1 is split into two by a beam splitter 39. The two lights are transmitted to the holography-deformation measuring instrument 5 by single mode fibers 40 and 41, respectively.

In the optical system configuration diagram of FIG. 5, the a beam from the Ar laser 1 is reflected by the first mirror 42 and becomes the b beam.

The B light beam is reflected by the 171-7th mirror 43 and becomes a C light beam whose course has been changed, and irradiates the object to be measured 0.

The d light flux, which is the object light reflected from the object to be measured O, is the first
Go straight through half mirror 43, 2nd) 1-7 mirror 44,
The recording material 45 is reached.

On the other hand, the other C light beam emitted from the Ar laser 1 [collimating optical system (not shown)] 1 is parallel to the tip of the trowel.
It is reflected by the half mirror 46, becomes an f light beam, and enters the recording material 45.

Since the object beam d and the reference beam f enter the recording material 45 at a constant angle, an interference fringe force is generated and recorded.

In the case of reading, the third mirror 48 strongly reflects the reference light 1 in the opposite direction to create a readout light beam g. The reference light f and the read light g travel in completely opposite directions and enter the recording material 45. The interference fringes recorded in the recording material 45 consist of the object beam d and the reference beam f! Therefore, when the reference light f and the readout light are applied simultaneously from opposite directions, a light flux h having a wave number vector in the completely opposite direction to the object light d is generated.

The h light flux creates a conjugate real image at the position where the object to be measured 0 once existed. The h light flux is reflected by the half mirror 44 to become the i light flux, which is reflected by the mirror 49 and then reflected by the half mirror 5.
0 and becomes j luminous flux. Among the j light flux and C light flux, the light flux (l! light flux) that has passed through the half mirror 46 interferes to form interference fringes.

Since the k light flux is a plane wave, this interference fringe represents the amount of deformation of the zero object from the ideal plane.

This is input into an image fiber 8, imaged by a television camera 3, and displayed on a television receiver 4.

FIG. 6 is a perspective view showing an example of an optical system corresponding to the configuration shown in FIG. 5 made of a glass block.

As in the previous example, the same reference numerals and numbers are given to the light beams of the same mirror and half mirror 1.

The method of dividing into blocks is arbitrary. The same applies to making mirrors and half mirrors by vapor depositing metal. A mass is made in the same manner as in the embodiment of FIG. 3, but the detailed description will not be repeated.

As described above, according to the present invention, a heavy and wide surface plate in which individual optical systems were fixed separately can be combined into one light and small block.

Since it is a block, the mutual positional relationship of the optical systems is fixed. Generally speaking, holography technology has strict conditions such that the positional shift must not be more than 1/8 of the wavelength of the light.

In the present invention, such conditions can be easily met. It is lightweight and small, making it convenient to handle. The range of objects to be measured is widened, expanding the range of uses. We will be able to accurately measure the minute deformations of various objects, such as measuring the deformation of IC boards and film thickness in passivation.

Furthermore, since the lump and the light source (laser) are connected through an optical fiber and the output image is transmitted through an image fiber, the deformation measuring instrument can be installed at any location.

There are few restrictions due to location.

As a holographic recording material, BSO element, BGO element f
Because it uses , it is possible to measure the deformation of an object in real time.

In the above embodiments, only mirrors, half mirrors, and dichroic mirrors were made of glass blocks, but the invention is not limited thereto.

If the object to be measured is large, it is necessary to expand the laser beam from the single mode fiber. At this time, lenses must be used in combination, but the lenses can also be tied together and fixed to a glass block. By using materials with different refractive indexes, lenses can be effectively constructed into glass blocks.

Of course, concave mirrors, convex mirrors, etc. can be stored inside the glass block.

Although the present invention has been described in detail using a holographic deformation measuring optical system as an example, this technique is also applicable to image processing optical systems such as Fourier transform, spatial frequency filtering, and image correlation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of the present invention. FIG. 2 is a diagram showing an example of the configuration of an optical system when holography is created by the double exposure method, and FIG. 3 is a perspective view of the configuration of a glass block according to an embodiment of the present invention, which corresponds to the case using the double exposure method. FIG. 4 is a schematic diagram of the configuration of the present invention using the phase co-projection method. FIG. 5 is a diagram showing an example of the configuration of an optical system for creating a phase conjugate hologram. FIG. 6 is a perspective view of the structure of a glass block according to another embodiment of the present invention, which corresponds to the case of the phase co-projection method shown in FIG. 1... Ar laser 2-11e-Ne laser 3 ・Par 1" ■ Camera 4- Television receiver 5, ・Holography deformation measuring instrument 6 ・・Single mode fiber 7 ・・Single mode fiber 8, Image fiber 9...No. 1 mirror 10, half mirror 11...second mirror 12, dichroic mirror 13...recording material 14...third mirror 15...fourth mirror 16...th 5 mirrors 21, 22,..., glass block 40
, 41... Single mode fiber 42...
...First mirror 43...First half mirror 44...Second half mirror 45...Recording material 46...Third half mirror 47, 48, 49... · mirror
-0...Object to be measured

Claims (1)

[Claims] A glass block of an appropriate shape and size, a thin film having a desired wavelength transmission characteristic coated on an appropriate surface of the glass flock, a rod lens with a uniform refractive index distribution, a Bi 12S iOzo element or a B112GcO element.
An image processing optical system that has an image processing function and is constructed by bonding together image recording materials made of ZO elements as a block.