JP2010032589A - Optical system for correcting light intensity distribution and biochip reading apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve efficiency of using light by enlarging a beam diameter and making intensity distribution flat by using a laser beam being collimated light having a small beam diameter. <P>SOLUTION: The optical system for correcting light intensity distribution is provided which improves the efficiency of using light by enlarging the beam diameter and making the intensity distribution flat by using the laser beam being the collimated light having the small beam diameter. The optical system includes a first lens group having a negative refracting power, which converts at least one collimated light into divergent light, a second lens group disposed behind the first lens group and having negative refracting power, which includes at least one lens, and a third lens group disposed behind the second lens group and having a positive refracting power, which includes at least one lens. The optical system diffuses, enlarges and collimates incident light emitted in parallel from a light source, and also emits it while making the intensity distribution of the incident light flat by the spherical aberrations of the respective lens groups. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light intensity distribution correcting optical system capable of obtaining a uniform intensity distribution and a sufficient amount of light by enlarging a thin parallel laser, and a biochip reader using this optical system.

  The following patent documents are known as prior art of the light intensity distribution correcting optical system.

JP 2006-317508 A

The above prior art has the following problems.
1. Since a thin parallel laser is not diverging light, the beam cannot be expanded and the intensity distribution cannot be flattened, and the light utilization efficiency is poor.

Accordingly, the present invention has been made to solve the above-described problems of the prior art.
1. Diffuse a thin parallel laser.
2. The intensity distribution of the beam is made close to flat.
3. In 1.2, the light use efficiency is not lowered.
Accordingly, an object is to realize an optical system capable of obtaining a uniform intensity distribution and a sufficient amount of light.

An optical system of the present invention for achieving such a problem is as follows.
In a light intensity distribution correcting optical system characterized by using a parallel beam laser with a thin beam diameter, expanding the beam diameter and flattening the intensity distribution, and improving the light utilization efficiency.
A first lens group having negative refracting power for converting at least one of the parallel light into divergent light, and a second lens group having negative refracting power, which is arranged at the rear stage of the lens group and has at least one lens;
A third lens group disposed at a subsequent stage of the second lens group and having a positive refractive power composed of at least one lens;
Have
A light intensity distribution correcting optical system characterized in that incident light from a light source emitted in parallel is diffused, magnified and collimated, and the intensity distribution of the incident light is flattened by spherical aberration of each lens group.

The light intensity distribution correcting optical system according to claim 1, wherein the first lens group and the second lens group are in close contact with each other.

  3. The light intensity distribution correcting optical system according to claim 1, wherein an amount of the spherical aberration is approximately 40% or more of a focal length of the first lens group.

In claim 4, in the biochip reader that irradiates the biochip surface with the incident light from the light source by the objective lens,
4. The objective lens according to claim 1, wherein the incident light is collimated using the light intensity distribution correcting optical system according to claim 1, and the intensity distribution of the incident light is flattened by spherical aberration of each lens group. A biochip reader characterized by being made to enter.

As is apparent from the above description, according to claims 1 to 4 of the present invention, the following effects can be obtained.
When applied to a biochip reader, by expanding the laser beam with a narrow parallel beam diameter to a beam diameter that can irradiate the entire sample and flattening the intensity distribution of the beam, and further improving the light utilization efficiency, A light intensity distribution correction optical system with improved screen brightness can be realized.

  FIG. 1 is a main part configuration diagram showing an example of an embodiment of a light intensity distribution correcting optical system of the present invention.

  In FIG. 1, a laser shutter 18 turns on and off a thin parallel laser beam from a laser (not shown). Reference numeral 19 denotes a beam diameter enlarging lens, which is disposed at a position away from the laser shutter 18 by a predetermined distance, and converts it into divergent light by radially expanding the beam diameter.

  Reference numeral 20 denotes an intensity distribution correction optical system, which is disposed at a position away from the magnifying lens 19 by a predetermined distance. The intensity distribution correcting optical system 20 uniformizes the light intensity distribution which is a Gaussian distribution of the laser light diverged by the magnifying lens. The uniformized light is guided to the irradiation surface through the mirror 3 and DM4.

  FIG. 2 is a block diagram showing an example of a light intensity distribution correcting optical system used in the present invention. The configuration of this light intensity distribution correcting optical system is disclosed in Japanese Patent Laid-Open No. 2006-317508.

  FIG. 2 shows details of the intensity distribution correcting optical system 20. In the figure, a light source 30 is diverging light from a laser beam transmitted through the magnifying lens 19 shown in FIG. The first convex lens 31 causes the diverging light to be refracted by the positive refractive power toward the optical axis side and enter the concave lens 32 while reducing the beam diameter. The concave lens 32 refracts the light emitted from the first convex lens 31 to the outside with a negative refractive power so as to be almost parallel light.

  The spherical aberration of each lens makes the Gaussian distribution of light intensity when output from the light source a flat light intensity distribution. Each lens group is not limited to a single lens, and may be composed of a plurality of lenses.

This will be described with reference to FIG. FIG. 3 is an explanatory diagram for explaining the spherical aberration of the lens. In FIG. 3A, in the convex lens 34, the light beam incident on the outer peripheral side of the convex lens 34 converges to the focal length f1 near the lens due to the spherical aberration. Is converged to a focal length f2 farther than f1.

  In FIG. 3B, in the concave lens 35, due to spherical aberration, the light beam incident on the outer peripheral side has a large spread angle, and the light beam incident on the inner periphery has a small spread angle. In FIG. 3B, the focal lengths f3 and f4 are distances to the point where the extension line (broken line) of the diverging light beam when parallel light enters is converged. This focal length is short (f3) on the outer periphery of the concave lens 35 and far (f4) on the inner periphery due to spherical aberration.

Returning to FIG. 2, in the first convex lens 31, due to spherical aberration, the light beam in the central part with high light intensity becomes nearly parallel, and the light beam in the peripheral part with low light intensity is collected in the central part.
In addition, since the entire diameter of the concave lens 32 is reduced by the first convex lens 31, the beam is incident on the inside of the concave lens 32, so that the spherical aberration of the concave lens 32 is weakened, and the entire beam becomes close to parallel light and the light intensity distribution. Can be flattened.

  The second convex lens 33 enables zooming by enlarging the narrowed beam diameter. Actually, a more uniform light intensity distribution is realized by combining the spherical aberrations of the first convex lens 31, the concave lens 32 and the second convex lens 33. In this case, if the spherical aberration amount is approximately 40% or more of the combined focal length of the first convex lens 31, such an effect can be obtained.

FIG. 4 is a diagram showing the effect of the light intensity distribution correction described above.
4A and 4B, the vertical axis indicates the relative intensity of the beam, and the horizontal axis indicates the beam diameter. In this example, divergent light from the optical fiber end face with NA = 0.09 is used at the position of the light source 30 in FIG.

FIG. 4A shows the intensity distribution (Gaussian distribution) of the beam before correction of the light intensity distribution, in which there is an intensity peak at the center of the beam, and the intensity is attenuated toward the periphery.
On the other hand, FIG. 4B shows a distribution after correction of the light intensity distribution, and the light intensity is sharply attenuated at a distance a from the center of the beam, but in the necessary field of view 2a. It can be seen that the distribution is corrected almost uniformly.

Even when the light intensity distribution is corrected, it can be said that the value of the shading S indicated by the difference in beam intensity at the distance a from the peak of the beam intensity (the center of the beam) is almost the same.
From this result, the beam intensity distribution is flattened within the allowable shading S, and the incident efficiency to the aperture (field diameter 2a) is approximately 22% of the amount of light emitted from the fiber before correction. It has been confirmed that this is about 58% after correction, which is improved by 2.6 times.

  As described above, the divergent light can be collimated by the three spherical lenses, and the light intensity distribution can be corrected to be flat within a necessary visual field.

FIG. 5 is a diagram showing a configuration of an optical system in a biochip reader using the light intensity distribution correcting optical system of the present invention.
As shown in FIG. 5, the biochip reader of the present embodiment includes an illumination optical system 200 using the light intensity distribution correction optical system of the present invention that irradiates excitation light onto the surface 110 of a transparent biochip 100, and this An imaging optical system 300 that forms a fluorescent image based on the excitation light irradiated by the illumination optical system 200.

  A plurality of cells are two-dimensionally arranged on the surface 110 of the biochip 100, and a fluorescent sample is injected into each cell.

  A transparent rotating plate 123 in which a microlens 123a is formed is provided at the subsequent stage of the illumination optical system 200. The rotating plate 123 is attached to the rotating shaft 125 of the motor 124 and is rotated by the driving force of the motor 124. When the parallel light from the illumination optical system 200 enters the rotating plate 123, each microlens 123a collects the laser light and irradiates the biochip 100.

  When the rotating plate 123 is rotated by the motor 124, the surface 110 of the biochip 100 is scanned by the excitation light beam narrowed by each microlens 123a. The microlens 123a is arranged on the rotating plate 123 in a spatial positional relationship so that each beam can individually scan each cell of the biochip 100. With such a configuration, generation of speckle noise can be prevented.

The imaging optical system 300 includes a lens 131, a barrier filter 132 that removes excitation light and selectively transmits only fluorescence, and an objective lens 133. The fluorescence from the cell of the biochip 100 excited by the excitation light enters the light receiver 114 through the lens 131, the barrier filter 132, and the objective lens 133, and forms an image on the light receiver 114.

The above description merely shows a specific preferred embodiment for the purpose of explanation and illustration of the present invention.
Therefore, the present invention is not limited to the above-described embodiments, and includes many changes and modifications without departing from the essence thereof.

It is a principal part block diagram which shows an example of embodiment of the light intensity distribution correction | amendment optical system of this invention. It is a block diagram which shows an example of the light intensity distribution correction | amendment optical system used by this invention. It is explanatory drawing explaining the spherical aberration of a lens. It is a figure showing the effect of light intensity distribution correction. It is a principal part block diagram of a biochip reader.

Explanation of symbols

3 Mirror 4 DM (Dichroic Mirror)
DESCRIPTION OF SYMBOLS 18 Laser shutter 19 Beam expansion lens 20 Light intensity distribution correction | amendment optical system 31 1st convex lens 32 Concave lens 33 2nd convex lens 34 Convex lens 35 Concave lens 100 Biochip 110 The surface of a biochip 114 Light receiver 123 Rotating plate 123a Micro lens 124 Motor 125 Rotating shaft 131 Lens 132 Barrier Filter 133 Objective Lens 200 Illumination Optical System 300 Imaging Optical System

Claims (4)

In a light intensity distribution correcting optical system characterized by using a parallel beam laser with a thin beam diameter, expanding the beam diameter and flattening the intensity distribution, and improving the light utilization efficiency.
A first lens group having negative refracting power for converting at least one of the parallel light into divergent light, and a second lens group having negative refracting power, which is arranged at the rear stage of the lens group and has at least one lens;
A third lens group disposed at a subsequent stage of the second lens group and having a positive refractive power composed of at least one lens;
Have
A light intensity distribution correcting optical system characterized in that incident light from a light source emitted in parallel is diffused, magnified and collimated, and the intensity distribution of the incident light is flattened by spherical aberration of each lens group. The light intensity distribution correcting optical system according to claim 1, wherein the first lens group and the second lens group are in close contact with each other.   3. The light intensity distribution correcting optical system according to claim 1, wherein an amount of spherical aberration is approximately 40% or more of a focal length of the first lens group. 4. In a biochip reader that irradiates the biochip surface with incident light from a light source by an objective lens,
The incident light is collimated using the light intensity distribution correcting optical system according to any one of claims 1 to 3, and the intensity distribution of the incident light is flattened by spherical aberration of each lens group. A biochip reader characterized by being incident on an objective lens.