JP2000356586A - Surface plasmon sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized and inexpensive surface plasmon sensor device. SOLUTION: A sensor device utilizes a surface plasmon resonance method having a prism 5 for allowing exciting light of surface plasmon to be incident on a sensor element 6 to transmit the reflected light from the sensor element 6 through a detector 7 and the detector 7 detecting the light reflected from the sensor element 6. In this case, the light incident on the prism 5 is set to radiation beam. This method develops the effect capable of miniaturizing the apparatus as compared with such a case that the incident light to the prism 5 is condensed parallel beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a sensor device for detecting an object to be measured and outputting a predetermined signal.
In particular, the present invention relates to an improvement in a part of a sensor device using light in a biosensor field using an enzyme reaction such as an antibody antigen reaction or a catalytic reaction.

[0002]

2. Description of the Related Art In a metal, free electrons vibrate collectively to generate a compression wave called a plasma wave. And, the quantization of this compression wave generated on the metal surface is
It is called surface plasmon.

Conventionally, various surface plasmon sensors for quantitatively analyzing a substance in a sample by utilizing the phenomenon that surface plasmons are excited by light waves have been proposed.
Among them, a particularly well-known one uses a system called a Kretschmann configuration (see, for example, JP-A-6-167443).

A surface plasmon sensor using the above system basically includes a prism, a metal film formed on one surface of the prism and brought into contact with a sample, a light source for generating a light beam, and a light source for the prism. An optical system that passes through the interface between the prism and the metal film so as to obtain various angles of incidence, and a light detection that can detect the intensity of the light beam totally reflected at the interface at each of various angles of incidence. Means.

When a light beam is incident on a metal film at an incident angle θ equal to or larger than the total reflection angle, a “smear wave” called an evanescent wave is generated in the metal film on the reflection surface. The evanescent wave has an electric field distribution in the sample in contact with the metal film, and surface plasmons are generated at the interface between the metal film and the sample. When the wave vector of the evanescent wave generated by the incidence of the p-polarized light beam on the metal film is equal to the wave vector of the above-described surface plasmon and the wave number matching is established, both are in a resonance state, and the light energy is changed to the surface plasmon. The plasmon is excited by the migration. At this time,
Due to the transfer of light energy, the intensity of the totally reflected light is significantly reduced.

Therefore, in the surface plasmon sensor, the intensity of the light beam totally reflected by the metal film is measured for the light beam incident on the metal film at various angles of incidence θ, so that the reflected light is measured. An incident angle θ _sp (a total reflection angle elimination angle) at which a phenomenon in which the intensity is significantly reduced is obtained. From the total reflection elimination angle θ _sp and the wave number vector K _{1 of the} incident angle, the resonance wave number K _sp becomes K _sp = It is derived from the relationship of K ₁ sin θ _sp . When the wave number K _{sp of the} surface plasmon is known, the dielectric constant of the sample is obtained. That is, if the angular frequency of the surface plasmon is ω, the high speed in vacuum is c, the permittivity of the metal and the sample is ε _m and ε _s , respectively, the following relationship is obtained.

[0007]

(Equation 1) If the dielectric constant ε _s of the sample is known, the concentration of the specific substance in the sample can be determined based on a predetermined calibration curve or the _{like.Therefore,} by knowing the total reflection elimination angle θ _{sp at} which the reflected light intensity decreases, the sample can be obtained. Quantitative analysis of a specific substance in it is possible.

The surface plasmon sensor can be used for a chemical sensor such as a gas sensor, a biosensor using an antibody-antigen reaction, and the like because it can measure the refractive index of a medium near the sensor element surface.

The above-mentioned sensor has already been put to practical use as a biosensor for immobilizing an antibody on a sensor element and detecting and quantifying proteins, nucleic acids, and other biological substances to which the antibody specifically binds. .

[0010]

The surface plasmon sensor device that has been used is focused on a light beam emitted from a light source by using a focusing lens for focusing the light beam on the sensor element surface. Therefore, the size of the lens itself, the focal length of the lens, and the like cause problems such as an increase in the size of the sensor device and an increase in the cost of manufacturing a condenser lens.

When the light incident on the prism is condensed, there is a problem that the cost increases due to the use of a lens or the like, and the size of the apparatus for adjusting the focal length increases. In the case of (1), the angle of the parallel light must be adjusted to an angle at which surface plasmon resonance occurs, and there is a problem that the structure becomes complicated and the device becomes expensive and large.

Accordingly, an object of the present invention is to provide a small and inexpensive sensor device.

[0013]

According to the first aspect of the present invention,
A surface plasmon resonance method including a prism for causing excitation light of surface plasmon to enter a sensor element and transmitting reflected light reflected by the sensor element to a detector, and a detector for receiving light reflected from the sensor element Wherein the light incident on the prism is radiated light. In the present invention, an effect that the device can be reduced in size can be obtained as compared with the case where the light incident on the prism is condensed and parallel light.

According to the second aspect of the present invention, by arranging the light radiating means between the light source and the prism, radiated light can be obtained regardless of the type of the light source.

According to the third aspect of the present invention, by disposing the light scattering means between the light source and the prism, even if there is an obstacle on the light path, an image of the obstacle is largely displayed on the sensor element side. Can be reduced.

The light scattering means can be constituted by a light diffusing means. Preferably, the light scattering means is one which can uniformly diffuse transmitted light and can control a light diffusion angle and a light traveling path. Thus, the light beam processed to the specifications of the sensor device can be incident on the prism.

The problem of an image caused by an obstacle in the light traveling path is particularly likely to occur when the light emitting means is provided on the light source side. According to the invention of claim 3, this problem can be solved. It is.

The invention according to claim 6 is characterized in that the light scattering means is integrally formed with the light emitting means.

In the present invention, since the positional relationship between the light scattering means and the light radiating means is constant, the angle of the light to be incident on the prism and the light path are determined by positioning only the integrated parts. Can be constant.

In addition, since the surface plasmon sensor device is formed integrally, it is easy to assemble the optical system of the surface plasmon sensor device and to replace the optical system with a new one integrally formed.

The invention according to claim 7 is characterized in that the light emitting means is a light shielding member having a pinhole.

In the present invention, since the light beam emitted from the light source can be processed into radiation having a certain aperture angle,
There is an effect that light having a plurality of incident angles can be incident on the sensor element at a time.

The light-shielding member having a pinhole can be processed by operations such as sputtering, vacuum deposition, etching, and pressing while the pinhole portion is masked, so that it is cheaper and easier than a lens. This has the effect of being able to be manufactured.

The invention according to claim 8 is characterized in that the light emitting means is a slit.

In the present invention, since the light beam emitted from the light source can be processed into radiation having a constant aperture angle,
There is an effect that light having a plurality of incident angles can be incident on the sensor element.

The ninth aspect of the present invention is characterized in that the light scattering means is a translucent member.

In the present invention, by providing the translucent member, the light diffusing member can be supplied inexpensively, easily, and in a free shape.

According to a tenth aspect of the present invention, the light scattering means comprises:
It is characterized in that it is a hologram.

In the present invention, by providing a hologram, it is possible to uniformly scatter and diffuse transmitted light, and it is also possible to simultaneously control the diffusion angle and course of light.

According to an eleventh aspect of the present invention, the light scattering means comprises:
It is a polarizer member.

In the present invention, the light is processed into P-polarized light by the polarizer member, and since the polarizer member itself is a light scattering and diffusing means, it is simultaneously processed into P-polarized light and scattered.
It becomes possible to spread.

Further, since the polarizer member itself has the light scattering means, the members can be integrally formed, and the assembly is easy at low cost.

It is preferable that the polarizer member has a hologram provided on the surface of the polarizer. It is characterized by the following.

According to a thirteenth aspect of the present invention, the light emitting means comprises:
It is characterized in that the degree of light emission and the diameter of the hole through which light passes can be adjusted.

In the present invention, it is possible to adjust the intensity of light incident on the sensor element.

According to the fifteenth aspect of the present invention, the light scattering means can adjust the degree of light diffusion, and can input a light beam processed to the specifications of the sensor device to the prism.

[0037]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a side sectional view showing the entire configuration of the sensor device of the first embodiment.

As shown in FIG. 1, the sensor device comprises a light source 1, a light shielding member 2 having a pinhole 3, a light diffusion adjusting member 4, a prism 5, a sensor element 6, a detector 7
A prism fixing upper member 8 having a flow path 10, a prism fixing lower member 9 having a function of positioning the excitation light emitting means 2 having the pinhole 3 and the prism 5, and a polarizer 11. ing.

The light source 1 uses an LED, and the light is emitted while being scattered. In addition, LED with collimating lens
Is used, the light is emitted as parallel light.

On the sensor element 6, a small amount of an object to be measured passes through the flow path 10 and is sent to the surface of the sensor element 6.

As a surface plasmon sensor device, light emitted from an LED is applied to a portion where an object to be measured is fed so that the range of the angle of incidence of the light spans the dip angle corresponding to the surface plasmon resonance and the angle range. Therefore, the light shielding member 2 having the pinhole 3 is disposed between the light source 1 and the prism 5.

By arranging the light shielding member 2, the light of the light source 1 scattered or emitted in parallel passes only from the pinhole 3, and the surface plasmon is transmitted to the sensor element 6 to which the object to be measured is sent. A dip angle corresponding to resonance and light straddling the angle are incident.

Further, by arranging the light shielding member 2, the range of the light irradiated on the sensor element 6 is adjusted.

The light incident on the sensor element 6 causes surface plasmon resonance on the sensor element 6, is reflected, passes through the prism 5, and is incident on the detector 7.

The light incident on the detector 7 is processed and output as a measurement result. The angle range of the light incident on the sensor element 6 can be adjusted by changing the size of the diameter of the pinhole 3 or the distance between the light shielding member 2 and the sensor element 6.

When the pinhole 3 is used, there is a characteristic that an image on the light source 1 side is projected on the sensor element 6 side. For example, when foreign matter such as dust enters between the light source 1 and the light shielding member 2, an image of the foreign matter is projected on the sensor element 6 side, which affects the measurement result.

Therefore, by disposing the light diffusing member 4 between the light shielding member 2 and the sensor element 6, the image on the light source 1 side is prevented from being projected on the sensor element 6 side.

FIG. 2 is a view showing a state of light diffusion when a translucent member is used as the light diffusion member 4 of the sensor device of the first embodiment. The arrows in the figure schematically show the traveling direction and intensity of light according to the direction and length.

As the light diffusing member 4, particles such as SiO ₂ and glass are mixed in a transparent resin such as a tape or a transparent resin such as acrylic or the like, which is roughened by giving irregularities to the surface of a transparent adhesive tape. A translucent resin member was used.

In the case of the above-mentioned translucent tape, if a commercially available tape is processed according to the shape of the light shielding member 2, the tape can be adhered to the tape. 4 can be easily and inexpensively formed as an integral member.

In the case of a resin member processed to be translucent by mixing the particles, a prism fixing lower member 9 having a function of positioning the light shielding member 2 having the pinhole 3 and the prism 5 and the shape of the light shielding member 2. And the shape of the prism 5 can be processed according to various uses.

When a translucent member is used as the light diffusing member 4, the light beam A) that has passed through the pinhole 3 passes through the translucent member to become a light beam A ′) and is incident on the sensor element 6. . Since the light beam A ′) has transmitted through the translucent member as compared with the light beam A), the light intensity is reduced. In order to perform the measurement, light having a certain light intensity or more is required. If the light intensity is lower than the certain light intensity, the light intensity of the light source 1 itself is increased to compensate for the reduced light.

However, when it is impossible to increase the intensity of the light source 1 itself due to the performance and cost of the LED and the power supply, it is necessary to prevent the intensity of the light passing through the light diffusing member 4 from decreasing. is there. Therefore, a hologram was used for the light diffusing member 4.

FIG. 3 is a diagram showing a state of light diffusion when a hologram is used for the light diffusion member 4 of the sensor device of the first embodiment.

When a hologram is used for the light diffusing member 4, the light beam B) that has passed through the pinhole 3 passes through the hologram to become a light beam B ′), and is incident on the sensor element 6. As the light beam B) transmitted through the hologram, the light beam diffused at any angle, like the light beam B ′), is uniformly diffused, so that the light intensity of the light source 1 is lower than that of the translucent member. It is possible to enter the sensor element 6 without reducing. Further, the diffusion angle of the transmitted light can be arbitrarily controlled at a designated angle, the X and Y directions of the diffusion angle can be controlled to individual angles, and the path of the light can be controlled. It is possible to control only by passing the angle and direction through the hologram.

As described above, when the wave vector of the evanescent wave generated by the incidence of the p-polarized light beam on the metal film is equal to the wave vector of the surface plasmon and the wave number matching is established, the two are brought into a resonance state. Then, the energy of light is transferred to the surface plasmon, and the plasmon is excited. Therefore, the polarizer 1 is disposed between the light source 1 and the sensor element 6.
1 is arranged. The light beam generated from the light source 1 passes through the polarizer 11, is p-polarized, and is incident on the sensor element 6.

Therefore, in order to reduce the size and cost of the sensor device, the surface of the polarizer 11 itself is provided with fine irregularities, and the function of the light diffusing member 4 is provided.
1 can be p-polarized and simultaneously diffused.

Further, since the surface of the polarizer 11 itself is processed so as to have a hologram function, the light transmitted through the polarizer 11 is p-polarized and simultaneously diffused uniformly, and the diffusion angle is arbitrarily controlled at a designated angle. This makes it possible to control the X and Y directions of the diffusion angle to individual angles.

[0060]

According to the present invention, since the light from the light source is not condensed by a lens and made incident on the sensor element, a light-shielding member having a pinhole or a slit is used, so that the size and focus of the condensing lens itself are reduced. A configuration that does not consider the distance can be adopted, and the size of the sensor device can be reduced.

A light-shielding plate having a pinhole can be easily manufactured because it can be processed by operations such as sputtering, vacuum deposition, etching, and pressing while the pinhole is masked.

Further, since the light diffusion control means is used, the aperture angle and the incident direction of the incident light can be adjusted without changing the diameter of the pinhole and the width of the slit.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of a sensor device according to the present invention as viewed from a side.

FIG. 2 is a diagram showing a light diffusion state when a translucent member is used as a light diffusion member of the sensor device of the present invention.

FIG. 3 is a diagram showing a light diffusion state when a hologram is used as a light diffusion member of the sensor device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Excitation light emission member, 3 ... Pinhole, 4 ...
Light diffusing member, 5: prism, 6: sensor element, 7: detector, 8: prism fixed upper member, 9: prism fixed lower member, 11: polarizer, A) light beam processed into radiation light, A ')… The light beam diffused by the translucent member,
B): Light beam processed into synchrotron radiation, B '): Light beam diffused by hologram

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Ohara 〒 2-1 1-1 Nakajima, Kokurakita-ku, Kitakyushu-city, Fukuoka Prefecture F-term in TOTO Kiki Co., Ltd. 2G059 AA05 BB12 CC16 DD13 EE02 EE05 FF06 GG02 JJ12 JJ19 KK01

Claims (15)

[Claims] 1. A prism for making surface plasmon excitation light incident on a sensor element and transmitting reflected light reflected by the sensor element to a detector, and a detector for receiving light reflected from the sensor element. A surface plasmon sensor device using a surface plasmon resonance method, wherein light incident on the prism is radiated light. 2. The surface plasmon sensor device according to claim 1, wherein light emitting means is provided between the light source and the prism. 3. The surface plasmon sensor device according to claim 1, wherein light scattering means is provided between the light source and the prism. 4. The surface plasmon sensor device according to claim 3, wherein said light scattering means is a light diffusion means. 5. The surface plasmon sensor device according to claim 3, wherein light emitting means is provided between the light source and the light scattering means. 6. The surface plasmon sensor device according to claim 5, wherein said light scattering means is integrated with said light emitting means. 7. The surface plasmon sensor device according to claim 2, wherein said light emitting means is a light shielding member having a pinhole. 8. The surface plasmon sensor device according to claim 2, wherein said light emitting means is a slit. 9. The surface plasmon sensor device according to claim 3, wherein said light scattering means is a translucent member. 10. The surface plasmon sensor device according to claim 3, wherein said light scattering means is a hologram. 11. The surface plasmon sensor device according to claim 3, wherein said light scattering means is a polarizer member. 12. The surface plasmon sensor device according to claim 11, wherein the polarizer member has a hologram provided on a surface of the polarizer. 13. The surface plasmon sensor device according to claim 2, wherein said light emitting means is capable of adjusting a degree of light emission. 14. The light emitting means according to claim 2, wherein said light emitting means is capable of adjusting a hole diameter through which light passes.
9. The surface plasmon sensor device according to claim 1. 15. The surface plasmon sensor device according to claim 3, wherein said light scattering means is capable of adjusting a degree of light scattering.