JP2001021830A - Confocal optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a common path type confocal optical scanner capable of improving S/N by adjusting the focal distances of a collimating lens and a microlens so that the size of a light source projected to a pinhole plate may be equal to or smaller than the diameter of a pinhole. SOLUTION: The size d1 of the light source 1 is projected to the surface of the pinhole plate 5b by the collimating lens 2 and the microlens formed on a microlens plate 3b. The focal distances of the lens 2 and the microlens are adjusted so that the size of the light source 1 projected to the pinhole plate 5b may be equal to or smaller than the diameter of the formed pinhole. The focal distance of the lens 2 is defined as f1, the focal distance of the microlens formed on the plate 3b is defined as f2 and the diameter of the pinhole formed on the plate 5b is defined as d2. In the case of satisfying (f2/f2).d1<=d2, a noise component is not made at all.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a confocal optical scanner using a white light source as a light source, and more particularly to a confocal optical scanner capable of improving S / N even in a common path type.

[0002]

2. Description of the Related Art A confocal optical scanner has a Nipkow plate having a plurality of pinholes (hereinafter referred to as a pinhole plate).
By rotating the sample, the surface of the sample is scanned, and a slice image of a plane perpendicular to the optical axis direction of the sample can be obtained.

FIG. 8 is a block diagram showing an example of such a conventional confocal light scanner. The confocal light scanner shown in FIG. 8 is a common path type confocal light scanner.
Here, the common path type refers to a configuration in which output light from a light source and return light from a sample pass through the same pinhole.

In FIG. 8, 1 is a light source such as a white light source, 2 is a collimating lens, 3 is a microlens plate on which a plurality of microlenses are formed, 4 is a light splitting means such as a dichroic mirror or a polarizing beam splitter, and 5 is a light splitting means. A pinhole plate in which a plurality of pinholes as openings are formed in the same pattern as the microlens, 6 is an objective lens, 7 is a sample, 8 is a lens, and 9 is a photodetector.

[0005] The output light of the light source 1 is collimated by the collimating lens 2 and is incident on the microlens plate 3. Each microlens formed on the microlens plate 3 transmits the incident light through the light branching means 4 to form a pinhole. Light is focused on each pinhole formed in the plate 5.

The output light transmitted through each pinhole formed in the pinhole plate 5 is condensed by the objective lens 6 and irradiated on the sample 7.

Return light such as fluorescence generated by irradiation of reflected light or output light from the sample 7 is again condensed by the objective lens 6 and passes through the same pinhole that has passed first. Then, the return light passing through the pinhole is reflected by the light branching means 4 and is incident on the photodetector 9 via the lens 8.

Here, the operation of the conventional example shown in FIG. 8 will be described. The output light from the light source 1 is passed through a collimating lens 2, a microlens plate 3, and a light branching unit 4 to a pinhole plate 5.
Then, the light passes through the pinhole formed in the sample 7 and is condensed by the objective lens 6 to irradiate the surface of the sample 7.

Return light such as fluorescent light generated by irradiation of reflected light or output light from the sample 7 is again the same pinhole that has passed through among the pinholes formed in the pinhole plate 5 by the objective lens 6 again. Is condensed to generate a confocal effect.

The return light is reflected and separated by the light branching means 4 and is incident on a photodetector 9 via a lens 8 to be detected as a confocal image. At this time, the photodetector 9
Is a slice image on a plane perpendicular to the optical axis at the focal position of the objective lens 6.

FIG. 9 is a block diagram showing another example of a conventional confocal light scanner. The confocal light scanner shown in FIG. 9 is a non-common path type confocal light scanner. Here, the non-common path type refers to a configuration in which output light from a light source and return light from a sample pass through different pinholes.

In FIG. 9, 1, 2, 6, and 7 are assigned the same reference numerals as in FIG. 8, and 3a is a microlens plate, 4a
Is a light splitting means such as a dichroic mirror or a polarizing beam splitter, 5a is a pinhole plate, 8a is a lens, 9a is a photodetector, and 10 and 11 are mirrors.

The output light of the light source 1 is converted into parallel light by the collimating lens 2 and is incident on the microlens plate 3a. Each microlens formed on the microlens plate 3a transmits the incident light to each pin formed on the pinhole plate 5a. Focus on the hole.

The output light transmitted through each pinhole formed in the pinhole plate 5a is transmitted through the light branching means 4a, is condensed by the objective lens 6, and is irradiated onto the sample 7.

Return light such as fluorescence generated by irradiation of reflected light or output light from the sample 7 is reflected again by the light splitting means 4a from the objective lens 6, is condensed via the mirror 10, and passes through the pin Pass through the pinhole opposite the hole. Then, the return light passing through the pinhole is reflected by the mirror 11 and passes through the lens 8a to the photodetector 9.
a.

Here, the operation of the conventional example shown in FIG. 9 will be described. Output light from the light source 1 passes through a pinhole formed in a pinhole plate 5a via a collimating lens 2, a microphone lens plate 3a, and a light branching means 4a, and is condensed by an objective lens 6 to be focused on the surface of a sample 7. Irradiated.

Return light such as fluorescence generated by irradiation of reflected light or output light from the sample 7 is again transmitted to the pinhole plate 5 by the objective lens 6 via the light branching means 4a and the mirror 11.
The condensed light is condensed on the pinhole on the side opposite to the pinhole that has passed first among the pinholes formed in a, and a confocal effect is generated.

The return light is reflected by the mirror 11, enters the light detector 9a via the lens 8a, and is detected as a confocal image. At this time, the confocal image obtained by the photodetector 9a becomes a slice image on a plane perpendicular to the optical axis at the focal position of the objective lens 6.

[0019]

However, in the conventional example shown in FIG. 8, not only the return light that has passed through the pinhole out of the return light, but also the light reflected by the pinhole plate 5 other than the pinhole. There is a problem in that the light is incident on the photodetector 9 as background light, thereby deteriorating S / N.

For example, FIG. 10 is an explanatory diagram for explaining the S / N problem of the common path type confocal optical scanner.
The reference numerals in 0 are the same as those in FIG. In FIG.
“OL01” and “OL02” are output lights from the light source, and “OL01” in FIG. 10 is a return light from the sample 7 that is irradiated on the sample 7 through a pinhole formed in the pinhole plate 5. In FIG. 10, "SL01" passes through the same pinhole and is reflected and separated by the light branching means 4.

On the other hand, the output light indicated by "OL02" in FIG. 10 does not pass through the pinhole of the pinhole plate 5 and is reflected by the surface of the pinhole plate 5, and the reflected light indicated by "BL01" in FIG. The light is reflected by the light branching means 4.

For this reason, the signal component indicated by "SL01" in FIG. 10 and the signal component "B" in FIG.
The noise component indicated by L01 "is both incident, and the S / N is deteriorated.

On the other hand, such a problem does not occur in the non-common path type confocal optical scanner shown in FIG.

For example, FIG. 11 is an explanatory diagram for explaining the problem of S / N of a non-common-path type confocal optical scanner. The reference numerals in FIG. 11 are the same as those in FIG. FIG.
“OL11” and “OL12” in the middle are output light from the light source, and “OL11” in FIG. 11 passes through a pinhole formed in the pinhole plate 5a and irradiates the sample 7, and
The light "SL11" in FIG. 11, which is the return light from, is reflected and separated by the light branching means 4a.

On the other hand, although the output light indicated by "OL12" in FIG. 11 does not pass through the pinhole of the pinhole plate 5a and is reflected on the surface of the pinhole plate 5a, the light branching means 4a does not exist in the optical path. Therefore, the photodetector 9a (not shown)
Is not incident on. However, the non-common-path confocal optical scanner as shown in FIG. 9 has a problem that the configuration is complicated and it is difficult to align and hold two pinholes. Therefore, an object of the present invention is to realize a confocal optical scanner which is a common path type and which can improve S / N.

[0026]

In order to achieve the above object, according to a first aspect of the present invention, in a common path type confocal optical scanner, a pinhole is provided via a collimating lens and a microlens. By adjusting the focal length of the collimating lens and the microlens so that the size of the light source projected on the plate is smaller than the formed pinhole diameter, all the images of the light source are collected in the pinhole. Since light is emitted, noise components can be significantly reduced even in a common path type.

According to a second aspect of the present invention, in the common path type confocal optical scanner, a light source, a collimating lens for converting output light from the light source into parallel light, and the parallel light are condensed by a formed microlens. A microlens plate, a light branching unit that transmits output light from the microlens plate, a pinhole plate irradiated with the transmitted light from the light branching unit, and each pinhole formed in the pinhole plate. An objective lens for collecting the passed light and collecting return light from the sample to each of the pinholes, and returning the return light passing through each of the pinholes and reflected by the light branching unit to a photodetector. A focus lens for the collimating lens and the microlens so that the size of the light source projected on the pinhole plate is equal to or less than the pinhole diameter. By adjusting the distance, since all of the image of the light source will be focused on the pinhole,
Even with a common path type, it is possible to greatly reduce noise components.

According to a third aspect of the present invention, in the confocal optical scanner according to the first and second aspects of the present invention, the light source is an output light from an output end of an optical fiber, so that the size of the light source is increased. It is possible to reduce the size.

According to a fourth aspect of the present invention, in the confocal optical scanner according to the first and second aspects, the output of the light source is condensed on a stop, and light passing through the stop is converted into parallel light. By irradiating the microlens, the size of the light source can be freely selected.

According to a fifth aspect of the present invention, in the confocal optical scanner according to the first and second aspects, a plurality of microlenses having the same focal length are formed on the microlens plate and the pin is provided. By forming pinholes having the same number and the same pattern as the microlenses on the hole plate and having the same diameter, it is possible to greatly reduce noise components even when there are a plurality of pinholes.

According to a sixth aspect of the present invention, in the confocal optical scanner according to the first and second aspects, all images of the light source are condensed in a pinhole due to the scanning type. Therefore, even in the case of the common path type, the noise component can be significantly reduced.

According to a seventh aspect of the present invention, in the confocal optical scanner according to the first and second aspects, all images of the light source are condensed in the pinhole due to the non-scanning type. Therefore, the noise component can be significantly reduced even in the common path type.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a confocal optical scanner according to the present invention. In FIG.
Reference numerals 2, 4, and 6 to 9 denote the same reference numerals as those in the conventional example shown in FIG. 8, 3b denotes a microlens plate on which one microlens is formed, and 5b denotes a pinhole on which one pinhole is formed. It is a board. Also, the connection relationship and the basic operation are the same as in the conventional example shown in FIG.

Here, the operation of the embodiment shown in FIG. 1 will be described. In FIG. 1, the size of the light source 1 is “d1”, the focal length of the collimator lens 2 is “f1”,
The focal length of the microlens formed in b is "f".
2 ", and the diameter of the pinhole formed in the pinhole plate 5b is" d2 ".

When the following equation is satisfied, FIG.
No noise component as shown in “BL01” is generated at all. (f2 / f1) · d1 ≦ d2 (1)

This situation is shown in FIGS. 2 and 3.
This will be described in more detail with reference to FIG. FIG. 2 is an explanatory diagram showing the relationship between each parameter, and FIG. 3 is a table showing an example of each parameter.

In FIG. 2, the size of the light source 1 is projected on the surface of the pinhole plate 5b by the collimating lens 2 and the micro lens formed on the micro lens plate 3b.
At this time, if the size of the light source 1 projected on the pinhole plate 5b is “d3”, d3 = (f2 / f1) · d1 (2) using the above parameters.

That is, the size of the light source 1 is "f2 / f
The light source 1 is multiplied by 1 "and projected on the pinhole plate 5b. At this time, as shown in FIG. 2, the projected size" d3 "of the light source 1 is the pinhole formed on the pinhole plate 5b. If the diameter is equal to or less than “d2”, all the images of the light source 1 are condensed in the pinhole and are not reflected by the pinhole plate 5b to become a noise component.

For example, as shown in FIG. 3, the size of the light source 1 is "d1 = 1.0 mm" and the diameter of the pinhole is "d2 = 0.
If the focal length of the collimating lens 2 is "f1 = 100 mm" and the focal length of the micro lens is "f2 = 5 mm", the size of the light source 1 projected on the pinhole plate 5b is "05 mm". d3 ″ is d3 = (5/100) · 1.0 = 0.05 [mm] (3)

That is, since the value shown in the equation (3) is equal to the pinhole diameter and satisfies the relationship of the equation (1), all the images of the light source 1 are condensed in the pinhole.

As a result, the focal length of the collimating lens 2 and the microlens is adjusted so that the size of the light source 1 projected on the pinhole plate 5b becomes smaller than the formed pinhole diameter, thereby achieving a common path type. Even if there is, it is possible to greatly reduce the noise component.

In the embodiment shown in FIG. 1, a white light source or the like is used as the light source. However, even if the light emitted from the optical fiber or the LED satisfies the relationship of the equation (1), the noise component is greatly reduced. It becomes possible.

For example, FIG. 4 is a partial block diagram showing an example of a case where light emitted from an optical fiber is used as a light source. 4, reference numeral 2 denotes the same reference numeral as in FIG. 1, and reference numeral 12 denotes an output end of the optical fiber.

In this case, the diameter of the output end of the optical fiber 12 indicated by "PD01" in FIG.
And the size of the light source can be reduced by selecting the diameter of the optical fiber. Further, the focal lengths of the collimator lens 2 and the microlens may be adjusted so as to satisfy the relationship shown in Expression (1).

Further, the size of the light source "d1" may be substantially reduced by temporarily stopping the output light of the light source 1 with a stop. FIG. 5 is a partial block diagram showing an example of a case where such an aperture is used. In FIG. 5, 1 and 2 are denoted by the same reference numerals as in FIG. 1, 13 is a lens, and 14 is a stop.

The output light of the light source 1 is transmitted through the
The light is condensed on the pinhole formed in 4. The output light that has passed through the pinhole formed in the stop 13 is converted into parallel light by the collimator lens 2 and is incident on the microlens plate 3b (not shown).

In this case, the substantial light source size "d"
Since "1" corresponds to the diameter of a pinhole formed in the aperture indicated by "PD02" in Fig. 5, the size of "d1" can be freely selected. The focal length can also be appropriately selected according to this.

Further, in the embodiment shown in FIG. 1, the case where one pinhole is formed in the pinhole plate 5b is exemplified. However, in the case where a plurality of pinholes are formed in the pinhole plate 5b. Even if the relationship of the expression (1) is satisfied, the noise component can be significantly reduced.

For example, in this case, the focal length of each microlens formed on the microlens plate 3b corresponding to each pinhole is equal to "f2 '", and the diameters of the plurality of pinholes are equal. Assuming that “d2 ′”, it suffices to satisfy the relational expression of (f2 ′ / f1) · d1 ≦ d2 ′ (4).

Further, in the embodiment shown in FIG. 1, a confocal light scanner using a pinhole plate (Nipkow plate) is exemplified, but it may be used for a non-scanning confocal light scanner.
For example, a confocal optical scanner using a plurality of microlenses and a pinhole array as shown in FIG.
A focal light scanner using a plurality of cylindrical lenses and slits as shown in FIG. 7 may be used.

In FIG. 6, reference numeral 15 denotes a light source, 16 denotes a collimating lens, 17 denotes a microlens plate on which a microlens is formed, and 18 denotes a pinhole plate on which a pinhole having the same pattern as the microlens is formed. .

In this case, the size of the light source 15 is "d4",
When the focal length of the collimating lens 16 is “f3”, the focal length of the microlens formed on the microlens plate 17 is “f4”, and the diameter of the pinhole formed on the pinhole plate 18 is “d5”. , (F4 / f3) · d4 ≦ d5 (5) If the expression is satisfied, no noise component is generated.

In FIG. 7, reference numerals 15 and 16 denote the same reference numerals as in FIG. 6, reference numeral 19 denotes a cylindrical lens plate on which a cylindrical lens is formed, and reference numeral 20 denotes a slit which is an opening having the same pattern as that of the cylindrical lens. It is the slit plate which was done.

In this case, the size of the light source 15 is "d4",
When the focal length of the collimating lens 16 is “f3”, the focal length of the cylindrical lens formed on the cylindrical lens plate 19 is “f5”, and the width of the slit formed on the slit plate 20 is “d6”, f5 / f3) · d4 ≦ d6 (6) When the expression is satisfied, no noise component is generated.

[0055]

As is apparent from the above description,
According to the present invention, the following effects can be obtained. Claims 1, 2,
According to the sixth and seventh aspects of the present invention, the size of the light source projected onto the pinhole plate via the collimating lens and the microlens is smaller than the formed pinhole diameter. By adjusting the focal length of the lens, all images of the light source are condensed in the pinhole, so that the noise component can be significantly reduced even in the common path type.

According to the third aspect of the present invention, the size of the light source can be reduced by using the output light from the output end of the optical fiber as the light source.

According to the fourth aspect of the present invention, the size of the light source can be freely selected by focusing the output of the light source on the aperture and irradiating the light passing through the aperture as parallel light to the microlens. It becomes possible. In addition, the focal lengths of the collimating lens and the microlens can be appropriately selected in accordance with this.

According to the fifth aspect of the present invention, a plurality of microlenses having the same focal length are formed on the microlens plate, and the pinhole plates have the same number of pinholes having the same number and the same pattern as the microlenses. Due to the formation, even if there are a plurality of pinholes, the noise component can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing an embodiment of a confocal optical scanner according to the present invention.

FIG. 2 is an explanatory diagram showing a relationship between parameters.

FIG. 3 is a table showing an example of each parameter.

FIG. 4 is a partial block diagram showing an example of a case in which light emitted from an optical fiber is used as a light source.

FIG. 5 is a partial block diagram showing an example of a case where an aperture is used.

FIG. 6 is a confocal optical scanner using a plurality of microlenses and a pinhole array.

FIG. 7 is a focal light scanner using a plurality of cylindrical lenses and slits.

FIG. 8 is a configuration block diagram showing an example of a conventional confocal optical scanner.

FIG. 9 is a configuration block diagram showing another example of a conventional confocal optical scanner.

FIG. 10 is an explanatory diagram for explaining a problem of S / N of the common path type confocal optical scanner.

FIG. 11 shows the S / N ratio of a non-common-path confocal optical scanner.
FIG.

[Explanation of symbols]

 Reference Signs List 1,15 Light source 2,16 Collimating lens 3,3a, 3b, 17 Micro lens plate 4,4a Light splitting means 5,5a, 5b, 18 Pinhole plate 6 Objective lens 7 Sample 8,8a, 13 Lens 9,9a Detector 10, 11 Mirror 12 Optical fiber 14 Aperture 19 Cylindrical lens plate 20 Slit plate

Claims (7)

[Claims] 1. A common-path confocal optical scanner, wherein the size of a light source projected onto a pinhole plate via a collimating lens and a microlens is smaller than a formed pinhole diameter. And a focal length of the microlens is adjusted. 2. A common-path confocal optical scanner, comprising: a light source; a collimator lens for converting output light from the light source into parallel light; a microlens plate for condensing the parallel light by a formed microlens; A light branching unit for transmitting the output light from the microlens plate, a pinhole plate irradiated with the transmitted light from the light branching unit, and condensing light passing through each pinhole formed in the pinhole plate And an objective lens for condensing return light from the sample on each of the pinholes, and a lens for condensing the return light reflected by the light branching means through each of the pinholes on a photodetector. The focal length of the collimating lens and the microlens is adjusted so that the size of the light source projected on the pinhole plate is equal to or smaller than the pinhole diameter. Confocal optical scanner according to claim. 3. The confocal optical scanner according to claim 1, wherein said light source is output light from an output end of an optical fiber. 4. The confocal optical scanner according to claim 1, wherein an output of said light source is condensed on a stop, and light passing through said stop is irradiated on said microlens as parallel light. 5. A microlens plate wherein a plurality of microlenses having the same focal length are formed, and the pinhole plate has pinholes having the same number and the same pattern as the microlenses formed on the pinhole plate. 3. The confocal optical scanner according to claim 1, wherein: 6. The confocal optical scanner according to claim 1, wherein said confocal optical scanner is of a scanning type. 7. A non-scanning type device according to claim 1, wherein:
And a confocal optical scanner according to claim 2.