JPH04330412A - Confocal optical scanner - Google Patents

Abstract

PURPOSE:To provide the confocal optical scanner which is improved in light utilization efficiency and reduces stray light from the surface of a pinhole substrate. CONSTITUTION:The confocal optical scanner rotates the pinhole substrate 10 and scans a sample with irradiation light passed through the pinhole substrate, and the pinhole substrate is equipped with plural light converging means and plural pinholes 14 arranged at the focus positions of the ligyt converging means. A Fresnel lens 13, a quadratice surface mirror or a small convex lens type microleses or distributed refractive index type plane microlenses are used as the light converging means. The light converging means form a light converging means group which have constatn width in a radial direction and is arranged in array in a circumerential direciton including means having focuses outside respective aperture pupils and the radial irradiation range of illumination light irradiating the light converging means group is limited to only the radial width of the light converging means group.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the light utilization efficiency of a confocal optical scanner for scanning a pinhole substrate used in a confocal microscope or the like.

0002

2. Description of the Related Art FIG. 6 is a diagram showing a conventional example of a pinhole substrate used in a confocal optical scanner, and FIG. 7 is a block diagram showing an example of a confocal microscope using a confocal optical scanner. 6 and 7, light emitted from a light source (not shown) passes through a polarizer 1a and a beam splitter 2, and then passes through a pinhole substrate 31 in which a plurality of pinholes 32 are spirally formed. 3 is irradiated. Of this irradiation light, the pinhole substrate 3
The light that has passed through some of the many pinholes 32 arranged spirally passes through the quarter-wave plate 4 and the objective lens 5, and is focused on the sample 6. The reflected light from the sample 6 passes through the same optical path and is focused on one of the pinholes 32 of the pinhole substrate 3, and passes through the pinhole 32 to the beam splitter 2 and the deflector 1b. sample 6 through eyepiece lens 7.
You can see the image of In this device, a pinhole substrate 3 is rotated at a constant speed by a motor 8.
By moving the pinhole 32 as the pinhole substrate 3 rotates, the focused light spot on the sample 6 is scanned.

0003

[Problems to be Solved by the Invention] However, the plurality of pinholes 32 arranged in a spiral manner as shown in the above-mentioned prior art
When light is irradiated from a light source (not shown) to the pinhole substrate 3 having a
There was a problem in that the light utilization efficiency was very low at 1% of the total light irradiated to the area, that is, 1%. Also, pinhole
The reflected light from the surface of the substrate 3 was also large, and this reflected light became stray light. In order to remove this stray light, the beam stop 7a of the eyepiece 7, the polarizer 1a, and the 1/4 wavelength plate 4 are used.
However, it is difficult to completely eliminate stray light, and the equipment is expensive.

The present invention has been made in view of the above-mentioned problems of the prior art, and improves the light utilization efficiency by providing a light condensing means on the light source side of the pinhole substrate. The object of the present invention is to provide a confocal optical scanner that can also reduce reflected light (stray light) from the surface.

[0005]

[Means for Solving the Problems] A first configuration of the present invention for solving the above problems is to rotate a pinhole substrate,
In a confocal optical scanner that scans a sample with irradiation light that has passed through the pinhole substrate, the pinhole substrate has a plurality of light condensing means and a plurality of light condensing means arranged at focal positions of the plurality of light condensing means. The invention is characterized by having a configuration including a plurality of pinholes. Further, in the second configuration, the plurality of light condensing means include a Fresnel lens, two
The present invention is characterized by a configuration using a curved mirror, a minute convex lens type microlens, or a refractive index distribution type flat plate microlens. Further, in the third configuration, the plurality of light condensing means, including those whose focal points are focused outside each aperture pupil, are arranged in a row in the circumferential direction with a constant width in the radial direction. The invention is characterized in that the irradiation range in the radial direction of the illumination light irradiated onto the condensing means group is limited to the width in the radial direction of the condensing means group. . Further, in a fourth configuration, the plurality of pinholes are formed by irradiating the pinhole substrate with a high-intensity laser beam through the plurality of light focusing means. It is characterized in that it is formed in accordance with the light condensing position of the means.

[0006]

[Operation] According to the present invention, the pinholes are arranged at the focal positions of the plurality of focusing means, so that more incident light can be focused on the pinholes through the plurality of focusing means. can. Furthermore, by employing a condensing means that focuses outside the aperture pupil, the area irradiated with light can be reduced, so that the light utilization efficiency can be improved. Furthermore, the pinhole on the pinhole board
Since light that has been irradiated onto surfaces other than the pinhole can also be focused onto the pinhole, reflected light (stray light) from the pinhole substrate surface can be reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings. FIG. 1 is a block diagram showing a first embodiment of a pinhole substrate used in a confocal optical scanner of the present invention. In FIG. 1A, a thin film 12 is formed on one surface of a glass substrate 11, and a Fresnel lens 13 is formed on the other surface. The thickness t of the glass substrate 11 is made equal to the focal length of the Fresnel lens 13 formed on one surface of the glass substrate 11, and a pinhole 14 is provided on the thin film 12 at the focal position of the Fresnel lens 13. There is. Here, the alignment of the Fresnel lens 13 and the pinhole 14, that is, the method of forming the pinhole 14, is performed by forming the pinhole 14 using a semiconductor mask pattern, and by injecting a high-intensity laser beam from the Fresnel lens 13 side. There are also methods such as evaporation, heat treatment, decolorization, etching, etc. of the thin film to facilitate alignment on the thin film 12, so that the pinhole 14 is aligned with the Fresnel lens 13.
is formed at the light condensing position.

Further, as shown in FIG. 1(B), a plurality of Fresnel lenses 13 formed on one side of the glass substrate 11 are
By rotating the pinhole substrate 10 at a constant speed,
The focal position is sequentially shifted by Pr in the radial direction one screen at a time so that the pinhole image can be scanned over the sample.

FIG. 2 is a block diagram showing an embodiment in which the confocal optical scanner of the present invention is used in a confocal microscope. The pinhole substrate constituting the confocal optical scanner is the one shown in FIG. 1. In FIG. 2, light emitted from a laser light source (not shown) (not only laser light but also white light may be used) is incident on a pinhole substrate 10 as parallel light by a polarizing beam splitter 2. . Pinho
As shown in FIG. 1(A), the light incident on the Fresnel lens 13 collects the incident light on the entrance of the pinhole 14 formed at the convergence position of the Fresnel lens 13, and passes through the Fresnel lens 13. More light is focused through the lens 13. Returning to FIG. 2, the light that has passed through the pinhole 14 passes through the quarter-wave plate 4 and is then irradiated onto the sample 6 by the objective lens 5. The reflected light from the sample 6 passes through the pinhole substrate 10 again, enters the light receiver (camera) 8 via the polarizing beam splitter 2, and displays the sample 6 on the monitor 9.
The image of is displayed. In this embodiment, the pinhole substrate 1
0 is rotated at a constant speed by a motor (not shown), and the pinhole 14 is rotated by the rotation of the pinhole board 10.
The image is scanning over the sample 6. Furthermore, the pinhole 14 on the pinhole substrate 10 and the light spot (pinhole image) on the sample 6 are in a confocal relationship, and both the incident light from the laser light source and the reflected light from the sample 6 are , and passes through the pinhole 14, high resolution can be obtained due to the confocal effect.

In the above embodiment, the light receiver 8 can be observed not only with a camera but also with the naked eye through an eyepiece. Further, as the light receiver, a photodiode or a highly sensitive photomultiplier tube can be used by providing one beam per screen. Furthermore, the polarizing beam splitter of the confocal optical scanner can also be used as a half mirror (a quarter-wave plate is not required).
By using a dichroic mirror as the splitter (a quarter wavelength plate is not required), the fluorescence of the sample can also be measured.

Furthermore, the number of beams is not limited to one per screen, but can also be multiple beams, making it possible to increase the amount of light per screen and increase the speed.

FIG. 3 is a block diagram showing a modified embodiment of the pinhole substrate of FIG. 1 used in the confocal optical scanner of the present invention. Note that in FIG. 3, the same elements as those in FIG. In Figure 3,
A pinhole 14 and a Fresnel lens 13 formed on a thin film 12 are separately attached to glass substrates 11a and 11b.
Glass substrates 11a and 11b are combined via a spacer 15 so that a pinhole 14 is located at the focal position of the Fresnel lens 13.

In this embodiment as well, as in the apparatus shown in FIG.
Since more light can be collected at the entrance of the pinhole 14 formed at the focal position of 3 and passed through the Fresnel lens 13, the light utilization efficiency can be improved and the apparatus shown in FIG. Compared to the above, since the thin film 12 and the Fresnel lens 13 can be formed on separate glass substrates, manufacturing becomes easier.

FIG. 4 is a block diagram showing a second embodiment of the pinhole substrate used in the optical scanner of the present invention. In FIG. 4, the same elements as those in FIG. 1 are given the same reference numerals, and redundant explanations will be omitted. In FIG. 4(a), Fresnel lenses 13 (F1, F2, F3,...) are arranged in a line in the circumferential direction, with a constant width B (aperture pupil width of the Fresnel lens) in the radial direction. It constitutes a Fresnel lens group. This Fresnel lens group includes, as shown in Figure 4 (b),
In addition to the Fresnel lens 13 whose focal point is within the aperture pupil of the Fresnel lens (F3 in the figure), the Fresnel lens 1
It also includes those whose focal points are outside the aperture pupil width B of the Fresnel lens (F1, F2, F4, F5 in the figure). Here, in order to form a Fresnel lens whose focal point is outside the aperture pupil width B, for example, in order to form a Fresnel lens F1, a large Fresnel lens with rotational symmetry about the focal point P1 is assumed. It can be formed by using a pattern in which the peripheral portion is cut out. Further, the radial irradiation range of the illumination light irradiated onto the pinhole substrate 10 is limited to the radial width of the Fresnel lens 13.

With this configuration, in the apparatus shown in FIG. 1, when the pinhole substrate rotating at a constant speed is irradiated with light, the image of the pinhole can be scanned over the sample. Pr the Fresnel lens in the radial direction one screen at a time.
They are formed by shifting one by one. Therefore, the irradiation light needs to illuminate the entire dimension A in the radial direction, but since only the aperture pupil width B of the Fresnel lens is irradiated onto the sample, the light utilization efficiency is B/A, and the light The utilization efficiency was improved compared to the conventional example, but it could not be said to be sufficient. In consideration of this point, the device shown in FIG. 4 further improves the light utilization efficiency. Returning to FIG. 4, as the pinhole substrate 10 rotates, the focal point Pi (i=1, 2, . . . ) scans over the sample. In this case, even though the radial irradiation range of the illumination light irradiated onto the pinhole substrate 10 is only the radial width B of the Fresnel lens 13, the pinhole image travels on the sample in the radial direction. The range of A can be scanned. Therefore, since the light irradiation area can be reduced, the light utilization efficiency becomes B/B, which can be further improved compared to the apparatus shown in FIG.

[0016] In addition to the Fresnel lens used in the confocal optical scanner shown in the above embodiment, other than the saw-shaped cross section shown in the figure, it is possible to use a Fresnel lens with a pattern of shading or phase difference, although this involves a decrease in the amount of light. A plurality of Fresnel zone plates arranged alternately in concentric circles may also be used. Further, the glass substrate may be made of plastic, and injection molding is also possible.

FIG. 5 is a block diagram showing a third embodiment of the pinhole substrate used in the optical scanner of the present invention. In FIG. 5, a plurality of 2
The curved mirror 22 is formed in a spiral shape. Second board 2
3 has the same number of pinholes 24 as the quadratic curved mirror 22.
is formed in a spiral shape. This first substrate 21 and the second
The substrate 23 is a pinhole at the focal position of the quadratic curved mirror 22.
The pinholes 24 are arranged so that they have the same center of rotation and are combined together using, for example, a spacer 25. When the pinhole substrate 20 rotates at a constant speed, the pinholes The image of the image can be scanned over the sample.

In such a configuration, when light from a light source (not shown) is incident on the quadratic curved mirror 22 of the pinhole substrate 20, the reflected light is placed at the focal position of the quadratic curved mirror 22. It is collected at the entrance of the pinhole 24. Therefore, since more light can be focused, the efficiency of light utilization can be improved, and since a lens is not used as a light focusing means compared to the device shown in FIG. 1 or 4, it is not affected by chromatic aberration caused by the lens. . Therefore, since there are no restrictions on the wavelengths that can be used, simultaneous irradiation of multiple wavelengths using RGB lasers or the like is possible, color images, etc. can be obtained, and it is easy to use ultraviolet light. Note that even with this configuration of the quadratic curved mirror, it is also possible to collect light outside the optical axis shown in FIG.

In the above embodiment, the condensing means for the pinhole substrate constituting the confocal optical scanner is as follows:
Instead of a Fresnel lens or a quadratic curved mirror, a micro-convex lens type microlens formed by partially shrinking crystallized glass, or a refractive index distribution formed by doping a low refractive index substrate with a high refractive index substance. A type flat plate microlens may also be used, and similar effects can be expected.

[0020]

Effects of the Invention As described above in detail along with the embodiments, according to the present invention, confocal light using a pinhole substrate in which pinholes are arranged at the focal positions of a plurality of condensing means can be realized. By using the scanner configuration, more incident light can be focused on the pinhole. Further, by employing a condensing means that focuses outside the aperture pupil width, the area of light irradiation can be reduced, so that the light utilization efficiency can be further improved. Even more pinho
Light that was previously irradiated on surfaces other than the pinhole on the pinhole can also be focused onto the pinhole, reducing reflected light from the pinhole substrate surface and simplifying the mechanism for removing stray light caused by surface reflected light. It is possible to realize a confocal optical scanner that has the effect of being able to reduce or remove the light.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of a pinhole substrate used in a confocal optical scanner of the present invention.

FIG. 2 is a configuration diagram showing an embodiment in which the confocal optical scanner of the present invention using the pinhole substrate of FIG. 1 is used in a confocal microscope.

FIG. 3 is a configuration diagram showing a modified embodiment of the pinhole substrate of FIG. 1 used in the confocal optical scanner of the present invention.

FIG. 4 is a configuration diagram showing a second embodiment of a pinhole substrate used in the optical scanner of the present invention.

FIG. 5 is a configuration diagram showing a third embodiment of a pinhole substrate used in the optical scanner of the present invention.

FIG. 6 is a conventional example of a pinhole substrate used in a confocal optical scanner.

FIG. 7 is a configuration diagram showing an example of a confocal microscope using a confocal optical scanner.

[Explanation of symbols]

2 Polarizing beam splitter 4 1/4 wavelength plate 5 Objective lens 6 Sample 8 Photo receiver 9. Monitor 10, 20 Pinhole board 11 Glass substrate 12 Thin film 13 Fresnel lens 14, 24 pinhole 21, 23 Board 22 Quadratic curved mirror 25 Spacer

Claims (4)

[Claims] 1. A confocal optical scanner that rotates a pinhole substrate and scans a sample with irradiation light that has passed through the pinhole substrate, the pinhole substrate comprising a plurality of light condensing means and , and a plurality of pinholes respectively arranged at focal positions of the plurality of condensing means. 2. The plurality of condensing means include a Fresnel lens, a quadratic curved mirror, a minute convex lens type microlens,
The confocal optical scanner according to claim 1, characterized in that the confocal optical scanner is configured using a gradient index flat plate microlens. 3. The plurality of light focusing means, including those whose focal points are focused outside each aperture pupil, have a constant width in the radial direction and are arranged in a row in the circumferential direction. 2. The light source according to claim 1, wherein the light means group is configured such that the radial irradiation range of the illumination light irradiated to the light condensing means group is limited to the radial width of the light condensing means group. Focusing optical scanner. 4. The plurality of pinholes are formed by applying a high-strength laser to the pinhole substrate via the plurality of light condensing means.
2. The confocal optical scanner according to claim 1, wherein the confocal optical scanner is formed to match the focusing position of the plurality of light focusing means by irradiating the laser light.