JP5219111B2 - Optical unit - Google Patents

Description

The present invention relates to an optical unit for illuminating a sample with an observation device such as a microscope. In particular, an intermediate such as a wavelength conversion filter is mounted in a light source beam, and the sample is illuminated and stabilized at an arbitrary specific wavelength. A quality image can be projected onto the light receiving section.

An observation apparatus for enlarging a sample and measuring its shape and dimensions precisely is widely used in various fields because it can easily perform high-precision measurement without contact. In recent years, it has been practiced to use a microscope or a projector as the observation device to illuminate a collected plant at a certain wavelength and to grasp the growth status of the plant from the observation result. Further, even in industrial samples, it is practiced to observe a minute displacement portion as a clear image using various principles of light absorption.

By the way, when observing various samples using an observation device such as a microscope or a projector, in order to stabilize the image quality of the entire optical system light receiving unit, for example, a device for making the density uniform and the wavelength constant. Ingenuity to do is required. In order to cope with such a situation, a wavelength conversion filter for adjusting light, for example, an interference filter (wavelength variable liquid crystal filter or the like) or a color filter is installed as an intermediate in the illumination optical system.
When a general halogen lamp is used as a light source for a microscope, the wavelength becomes a continuous spectrum. Even if a wavelength conversion filter or the like is installed as an intermediate to select a specific wavelength from this spectrum, if oblique rays are incident on the intermediate that is supposed to be used with a parallel beam, The quality may change between the central part and the peripheral part in the observed image. Specifically, if oblique rays from the outside of the optical axis enter the wavelength conversion filter, diffusion occurs, resulting in a difference in wavelength characteristics, and light traveling along the central optical axis of the wavelength conversion filter and the optical axis A color difference occurs between light traveling as oblique rays from the outside. When oblique rays are incident on an intermediate that is supposed to be used with a parallel light beam in this way, a difference in observation results occurs, and the purpose of observation at a specific wavelength is lost.

On the other hand, many examples of illumination optical systems such as a microscope using an optical fiber between a light source and a sample have been proposed so far. For example, in Patent Document 1, the incident end 32a is bundled, and the light from the light source 31 is directed to the slit 33 through the fiber bundle 32 in which the emission ends 32b are arranged in a line. The image of the slit 33 is projected onto the sample 22 through the optical system, and the reflected light is incident on the image sensor 24. As a result, the light from the emission end 32 b becomes a line shape corresponding to the shape of the slit 33, so that the amount of light passing through the slit 33 can be made uniform.
Moreover, in patent document 2, the light from the light source device 20 incorporating the halogen lamp 21 is directed from the fiber cable 30 to the condenser lens 10. Since the condensing lens 10 is attached in place of the eyepiece of the microscope, the light passing through the condensing lens 10 is applied to the sample A perpendicularly. As a result, an effect that the shortage of illumination light quantity can be solved is obtained.
As described above, most of the conventional illumination optical systems such as a microscope using an optical fiber are used as a light guide for guiding light from a light source to a sample.

It is possible to infer an optical system that uses an optical fiber as a light guide as shown in the above-mentioned patent document to direct light to an intermediate and illuminate the sample at a specific wavelength selected by the intermediate It is. In this case, the light beam from the light source directed toward the intermediate can be brought relatively close to the intermediate by using an optical fiber. However, it is difficult to obtain a perfect parallel light beam only by installing an optical fiber, and oblique rays always remain. If oblique rays remain, the function of the intermediate is impaired, and the above-described wavelength unevenness and density unevenness at the microscope light receiving portion occur. Therefore, simply installing an optical fiber does not solve the problem of oblique rays, and stable illumination light at a specific wavelength cannot be obtained. The type and material of the intermediate to be installed, even if you choose to use what was changed and its thickness, occurrence of wavelength unevenness is predicted. In the end, simply installing the intermediate and the optical fiber in the illumination optical system makes it impossible to freely perform illumination and observation utilizing these features.
JP-A-10-104523 JP 2000-292706 A

Therefore, the problem of the present invention is that various intermediates, particularly wavelength conversion filters, can be freely mounted in the sample illumination optical system of an observation apparatus such as a microscope, and the characteristics of the mounted intermediates and the characteristics of a specific single wavelength light source are utilized. In this way, the sample can be illuminated as it is, and the image can be observed on the light receiving part. Thus, the function as an observation apparatus is enhanced so that versatility can be improved.

In order to solve the above-described problems, the present invention provides a first optical fiber optical system having a random arrangement in which a light beam from a light source emitting a continuous spectrum is directed to an intermediate as a substantially parallel light beam , and a dispersion from the first optical fiber optical system. and intermediates for selecting any particular wavelength from within the source light beam by receiving the light beam as a light, a second optical fiber optically random sequence for directing the sample observation apparatus receives the light beam of a specific wavelength selected by the intermediate And an afocal optical system for magnification conversion is installed between the first optical fiber optical system and the intermediate and between the intermediate and the second optical fiber optical system, and enters through the intermediate. It is characterized in that the light beam is directed toward the sample as dispersed light.

In the present invention, an intermediate can be freely mounted in a sample illumination optical system such as a microscope, and the best effect can be obtained with the parallel light of the intermediate, and the feature of using a specific single wavelength light is utilized. The sample can be illuminated as it is. Since the light beam from the light source toward the intermediate is converted into a substantially parallel light beam, an optical unit with less generation of oblique rays can be obtained. Furthermore, the amount of light energy per unit area can be reduced and the damage given to the intermediate can be reduced by making the light flux toward the intermediate substantially parallel. Even if an adverse effect occurs due to an unpredictable phenomenon of the light flux that has passed through the intermediate, such as insufficient accuracy of the parallel light flux or material conversion of the intermediate, it is possible to remedy it and suppress the illumination unevenness to illuminate the sample. it can. Therefore, even if a C-MOS, CCD, or the like is installed in a light receiving unit such as a microscope, a stable image with a selected wavelength can be projected, and the function as an observation apparatus can be improved and versatility can be improved.

The present invention is an optical unit in an illumination optical system that directs light from a light source that emits a continuous spectrum, such as a halogen lamp, to a sample. Specifically, the light from the light source is directed to an intermediate that can be mounted by the first optical fiber optical system, and the light beam having a specific wavelength selected by the intermediate is directed to the sample by the second optical fiber optical system. It is a thing. An optical unit according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram illustrating the configuration of the entire observation apparatus 1. In the figure, light from a light source unit 2 that emits a continuous spectrum such as a halogen lamp illuminates a sample 5 installed in an observation optical system unit 4 through an optical unit 3. The reflected or transmitted light of the illuminated sample 5 is projected onto the light receiving unit 7 by the objective lens 6 and transmitted to the installed C-MOS, CCD 8, or the like. The image projected on the CCD 8 is sent to the display unit 10 via the control unit (personal computer) 9 and displayed. The personal computer 9 is connected to an input unit 11 such as a keyboard and a mouse, and various storage devices such as a CD-R and MO, and an output unit 12 such as a printer.
The observation optical system unit 4, the personal computer 9, and the display unit 10 may have general internal configurations. In particular, the configuration of the observation optical system unit 4 may be modified in various ways according to the purpose of use. .

FIG. 2 is an explanatory view showing the internal structure of the optical unit 3. In the figure, the light from the halogen lamp 13 accommodated in the light source unit 2 travels through the lens 14 to the input end 15 a of the first optical fiber optical system 15. The light incident on the input end 15a passes through the first optical fiber optical system 15 and travels from the output end 15b to the first afocal optical system 16 for magnification conversion. Two lenses 17 and 18 are accommodated in the optical system 16 and converted into a substantially parallel light beam while changing the magnification and directed toward the intermediate 19. The light beam that has passed through the intermediate 19 with the light beam converted to be substantially parallel goes to the second afocal optical system 20 for magnification conversion. Two lenses 21 and 22 are accommodated in the optical system 20, and the magnification is converted and sent to the input end 23 a of the second optical fiber optical system 23. The first afocal optical system 16 and the second afocal optical system 20 are substantially the same, and the arrangement of the lenses 17 and 18 is reversed to become lenses 21 and 22. The enlarged magnification is reduced by the second afocal optical system 20. The second optical fiber optical system 23 is composed of randomly arranged optical fibers, details of which will be described later. The light incident on the input end 23 a of the second optical fiber optical system 23 passes through the optical fiber optical system 23 and illuminates the sample 5 in the observation optical system unit 4 from the output end 23 b (FIG. 1).
The lengths of the first and second optical fiber optical systems 15 and 23 can be arbitrarily determined, and the arrangement of the light source unit 2 and the observation optical system unit 4 can also be arbitrarily determined. As described above, various kinds of intermediates 19 can be adopted. Although not shown in the figure, a mechanism that can be freely mounted between the two afocal optical systems 16 and 20 is provided, and the first afocal optical system is provided. 16 is positioned so that the light beam that has passed through the light from 16 is transmitted to the second afocal optical system 20.

FIG. 3 is an explanatory diagram of the first afocal optical system 16. In the figure, when the emission angle of light from the output end 15b of the first optical fiber optical system 15 toward the lens 17 is θ1, the emission angle θ2 of light emitted from the optical axis 24 of the lens 18 toward the intermediate 19 is ,
θ2 = θ1 / M (M = magnification)
Is required. That is, when the magnification M is increased, the value of θ2 decreases, and the light traveling toward the intermediate 19 approaches a parallel light flux. Accordingly, if the design values and positional relationships of the two lenses 17 and 18 are selected and the magnification M is set, the intermediate 19 can obtain the required parallel light flux. Accordingly, the intermediate 19 can select a single wavelength by eliminating oblique rays and taking advantage of the characteristics and characteristics of the intermediate. Further, increasing the beam diameter and converting the magnification with the lenses 17 and 18 increases the parallelism of the beam as described above, but also reduces the amount of light energy per unit area. The damage done can be reduced.
As described above, the second afocal optical system 20 is the same as the first afocal optical system 16, and the magnification enlarged by the first afocal optical system 16 is reduced to the input end 23 a of the second optical fiber 23. Let go.

FIG. 4 is an explanatory diagram of the second optical fiber optical system 23. FIG. A shows the input end 23a of the second optical fiber optical system 23, and FIG. B shows the output end 23b. FIG. A also shows arbitrary regions 25, 26, and 27 in the surface of the input end 23 a when the light beam that has passed through the intermediate 19 enters the input end 23 a through the second afocal optical system 20. ing. One region in the arbitrary region of the input end 23a, for example, 25 includes fibers a1, a2, and a3 in all the fibers constituting the second optical fiber optical system 23. The second arbitrary region 26 includes fibers b1, b2, b3, and b4. The third region 27 is an example in which fibers of c1, c2, c3, and c4 are included. The light beam irradiated on the entire area of the input end 23 a configured as described above travels through the second optical fiber optical system 23 toward the output end 23 b. At this time, since the second optical fiber optical system 23 is composed of the optical fibers of the random arrangement as described above, the light beam directed from the regions 25, 26, 27 to the output end 23b is larger than the fiber arrangement of the input end 23a. Injected into a changed fiber array. For example, as shown in FIG. B, in the fiber arrangement of the output end 23b, each of the arbitrary regions 25, 26, and 27 specified by the input end 23a collapses, and the fibers a1 to a3, b1 to b4, c1 to c4 is in a randomly distributed arrangement. Therefore, even if light passing through the intermediate 19 due to oblique rays is incident on one specific area, for example, 25, the light is dispersed and arranged in the entire output end 23b by the fibers a1, a2, and a3 on the output end 23b side, and oblique rays Average the effects of.

Further, even if light with high luminance is incident on the other regions 26 and 27 in a concentrated manner, the light is dispersed throughout the output end 23b by the fibers b1 to b4 and c1 to c4 that are dispersed and arranged at the output end 23b. The sample 5 is illuminated with an averaged luminance. The dispersive arrangement at the output end 23b is not limited to the regions 25, 26, and 27, but the entire arrangement of the entire input end 23a is dispersed to illuminate the sample 5. Therefore, the light flux that has passed through the intermediate 19 is inadequate in parallelism accuracy. Even if it exists, that is, even if it is a light beam that could not be converted into a completely parallel light beam by the first afocal optical system 16, the second optical fiber optical system 23 functions to relieve it. Similarly, even if the quality and accuracy of the intermediate 19 are not high-grade or converted to another type, the second optical fiber optical system 23 relieves it and illuminates the sample 5. . This means that even if an unpredictable phenomenon occurs in the light flux passing through the intermediate 19, the installation of the second optical fiber optical system 23 covers it.
As described above, according to the present invention, the second optical fiber optical system 23 of the optical unit 3 is configured by a random array of optical fibers, so that an image subjected to stable single-wavelength illumination can be obtained by the light receiving unit 7. .

FIG. 5 is an explanatory diagram showing the relationship between the first optical fiber optical system 15 and the luminance. Column A shows the input end 15a and the luminance of the irradiation light received from the light source unit 2 by the input end 15a. Column B shows the output end 15b and the brightness of the light that the output end 15b sends to the intermediate 19 through the first afocal optical system 16.
In row A, the input end 15a of the first optical fiber optical system 15 is irradiated with light from the light source unit 2, and arbitrary specific regions 25, 26, and 27 are shown as in FIG. (In order to clarify the positional relationship of each area, diagonal lines are added.) The average luminance of the light applied to the entire area of the input end 15a is a curve 28. According to this curve 28, the light from the halogen lamp 13 has a wavelength in the vicinity of 400 to 800 μm, and the maximum peak value (100%) is in the vicinity of 750 μm. When the light from the input end 15a that has been irradiated with such luminance is transmitted to the output end 15b, the brightness becomes a curve 28a as shown in the B1 column of the figure. The curve 28a is almost the same as the curve 28, but the light has been lost by the length of the first optical fiber optical system 15, and the curve 28 is also indicated by a dotted line for reference in the figure. is there. Arbitrary regions 25, 26, and 27 on the output end 15b shown in the B1 column are in the same arrangement state as that of the input end 15a in the A column.

However, in general, the arbitrary specific region on the input end side of the optical fiber optical system usually changes its arrangement greatly in units of region on the output end side. For example, there is a ratio of being biased to one side or concentrated in one place. high. The B2 column of FIG. 5 shows such a case. Although the regions 25, 26, and 27 from the input end 15a are arranged in units of regions at the output end 15b, the arrangement position changes greatly. And it is an example concentrated in one place. In this example, assuming that each region 25, 26, 27 in the A row is strongly irradiated with, for example, red light (700 to 800 μm), each region 25 is output at the output end 15b in FIG. , 26 and 27 are concentrated in one place, the brightness of the light toward the intermediate 19 becomes a light having a strong red wavelength with a peak near 750 μm as shown by the curve 29. The wavelength in the vicinity of 400 to 500 μm is weakened. In this way, when an optical fiber is used in which the arrangement of the arbitrary regions at the input end 15a and the output end 15b changes in units of regions, the output end 15b including the case of the above-described hypothetical example is also used. I can't predict how it will change on the side. Therefore, it is necessary to test one by one and see the result. Assuming that the light from the output end 15b is directed to the intermediate 19, it is assumed that the accuracy and quality of the intermediate 19 are not high-grade, or that the type and thickness of the intermediate are changed. The light flux passing through the intermediate becomes even more unpredictable.

FIG. 6 is an explanatory diagram showing the relationship between the second optical fiber optical system 23 and the luminance of the light that has passed through the intermediate, and column A is from the input end 23a and the second afocal optical system 20 received by the input end 23a. The emission light luminance is shown. The row B indicates the output end 23b and the luminance of the light sent from the output end 23b to the sample 5.
In the A1 column, the input end 23a of the second optical fiber optical system 23 is irradiated with light from the intermediate 19 and the second afocal optical system 20, and in the figure, arbitrary specific regions 25, 26, In this state, light from 27 is received as it is as regions 25, 26, and 27 of the same arrangement. The incident light has a luminance as indicated by a curve 30. According to this curve 30, a wavelength near 600 μm is selected by passing the light flux by the curve 28 a in the first row of FIG. 5B through the intermediate 19, and other wavelengths have a cut waveform.
However, it is also predicted that light other than the wavelength represented by the curve 30 will actually enter the input end 23a. That is, as described above, when the accuracy of the parallel light beam from the first optical fiber optical system 15 toward the intermediate 19 is low, light beams other than wavelengths near 600 μm also enter the input end 23a from the intermediate 19. . FIG. A2 column shows an example of incident light in such a case, where a wavelength in the vicinity of 400 to 500 μm and a wavelength in the vicinity of 700 to 800 μm are incident, which are shown as curve 31 and curve 32, respectively. It is. These curves 31 and 32 are obtained when the output end 15b of FIG. 5 is changed from the B1 row to the B2 row or when an unpredictable phenomenon occurs by changing the material of the intermediate 19 or the like. Also occurs. If such light is directly supplied to the sample 5 as illumination light, the illumination light becomes unstable.

The row B in the figure shows the output end 23b of the second optical fiber optical system 23 and the luminance of light emitted from the output end 23b. As described in FIG. 4B, the output end 23b is configured so that its fiber arrangement greatly changes from the fiber arrangement of the input end 23a. For example, the areas 25, 26, and 27 are also collapsed, and the internal fiber a1 Through a3, b1 through b4, and c1 through c4 are all randomly distributed. In the figure, the dispersed arrangement is the same as the arrangement of FIG. 4B, but the brightness of the light emitted from the output end 23b by the dispersed arrangement is as shown by a curve 33 in the figure. According to this curve 33, the wavelengths that created the curves 31 and 32 in FIG. 6A2 are dispersed and absorbed by the curve 33 so as to be integrated, and the brightness has a peak value in the vicinity of 600 μm. That is, the light beam from the second afocal optical system 20 incident on the input end 23a passes through the second optical fiber optical system 23 toward the output end 23b. At this time, the second optical fiber optical system 23 is configured. It is distributed and transmitted throughout the output end 23b by a random arrangement of fibers. By this dispersion, the light beam directed to the sample 5 is averaged without wavelength unevenness. Therefore, when light with high luminance is incident on the regions 25, 26, and 27, or when light such as the curves 31 and 32 is incident due to oblique rays passing through the intermediate 19. In addition, even if light that has been changed in advance unpredictably enters the input end 23a, the output end 23b always supplies the sample 5 with averaged light.

What has been described above is that the first optical fiber optical system 15 in the optical unit 3 is configured by a normal optical fiber, and the second optical fiber optical system 23 is configured by a random array of optical fibers. However, according to the purpose of the present application, the first optical fiber optical system 15 can also be obtained as a further effect by using a random array of optical fibers. In this case, the input end 23a in FIG. 4A may be read as the input end 15a of the first optical fiber optical system 15, and the output end 23b in FIG. 4B may be read as the output end 15b of the first optical fiber optical system 15. That is, when the light from the halogen lamp 14 in the light source unit 2 is received by the input end 15a of the first optical fiber optical system 15, the light enters the arbitrary regions 25, 26, and 27 (FIG. 4A) in the entire area of the input end 15a. The dispersed light is dispersed into a1 to a3, b1 to b4, and c1 to c4 (FIG. 4B) toward the output end 15b. The first afocal optical system 16 substantially converts this dispersed light into a parallel light beam and directs it to the intermediate 19. Accordingly, without causing the problem described with reference to FIG. 5, the intermediate 19 selects a predetermined wavelength and illuminates the sample 5 from the second afocal optical system 20 toward the second optical fiber optical system 23. . As a result, the sample 5 is illuminated with the light dispersed by the first and second optical fiber optical systems 15 and 23, and the light beam after passing through the intermediate 19 is made more reliable. As described above, this embodiment is characterized in that the first and second optical fiber optical systems 15 and 23 are randomly arranged optical fibers.

The optical unit of the present invention has been described as the first and second embodiments. In these embodiments, the connection method between the first and second optical fiber optical systems 15 and 23 and the first and second afocal optical systems 16 and 20 and the connection method between the light source unit 2 and the optical unit 3 will be described in detail. Not. Similarly, a method for connecting the intermediate 19 and the afocal optical systems 16 and 20 is not described in detail. However, these can be solved by combining existing ones and designing within an allowable range.

Schematic explaining the structure of the whole observation apparatus. Explanatory drawing which showed the internal structure of the optical unit. Explanatory drawing of a 1st afocal optical system. Explanatory drawing of a 2nd optical fiber optical system. Explanatory drawing which showed the relationship between a 1st optical fiber optical system and a brightness | luminance. Explanatory drawing which showed the brightness | luminance relationship of a 2nd optical fiber optical system and intermediate body passage light.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Observation apparatus 2 ... Light source part 3 ... Optical unit 4 ... Observation optical system part 5 ... Sample 7 ... Light-receiving part 8 ... CCD 9 ... Control part 10 * ··· Display unit 13 · · · Halogen lamp 15 · · · First optical fiber optical system 16 · · · First afocal optical system 19 · · · Intermediate 20 · · · Second afocal optical system 23 · · · Second optical fiber optical system 25, 26, 27 ... specific region

Claims (1)

A first optical fiber optical system in which a random sequence that directs the intermediate light flux from the light source which emits a continuous spectrum as substantially parallel light beam, the light source light beam in receiving a light beam as a dispersed light from the first optical fiber optical system An intermediate for selecting an arbitrary specific wavelength from the first optical fiber , and a second optical fiber optical system having a random array for receiving a light beam having the specific wavelength selected by the intermediate and directing it toward the sample of the observation apparatus. An afocal optical system for magnification conversion is installed between the optical system and the intermediate and between the intermediate and the second optical fiber optical system, and the incident light beam passing through the intermediate is directed to the sample as dispersed light. An optical unit characterized by illumination.