JP2001108612A - Surface plasmon resonance sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface plasmon resonance sensor that is compact, has improved sensitivity, at the same time, can be easily and optically connected to other optical elements, can be manufactured easily, and can improve sensitivity drastically. SOLUTION: The surface plasmon resonance sensor is provided with an optical waveguide that is formed by successively laminating a clad layer and a core layer on a substrate, and a sensor part that is formed by providing a metal thin film on the surface of the core layer of the optical waveguide. In the surface plasmon resonance sensor, the core layer and the clad layer of the optical waveguide have been formed by resin, a plurality of sensing parts of the sensor are arranged on one optical plane, light passes through the plurality of sensing parts optically and continuously, and the length of the sensing parts have been increased essentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention utilizes the surface plasmon resonance phenomenon caused by changing the wavelength of light or the angle of incidence of light, for example, a refractive index (or dielectric constant).
The present invention relates to a surface plasmon resonance sensor used for a liquid identification sensor for identifying a liquid by monitoring a change or a biosensor for measuring the concentration of a substance reacting with an antigen and specifying the substance.

[0002]

2. Description of the Related Art In recent years, in the fields of biochemistry, analytical chemistry and the like, technology for measuring physical properties of very small amounts of substances and identifying the substances has been actively developed. A surface plasmon resonance sensor that measures physical properties such as a refractive index or a dielectric constant by using the same, and as a result, identifies a substance concentration or a substance has attracted attention. Conventionally, such surface plasmon resonance sensors include:
A prism type surface plasmon resonance sensor which obtains surface plasmon resonance using a prism and an optical fiber type surface plasmon resonance sensor which obtains surface plasmon resonance using an optical fiber have been proposed.

In the former, a substance to be measured is arranged on a prism having a surface provided with a metal thin film such as gold, and light is incident on the prism at an angle of incidence equal to or greater than the total reflection angle, and the surface of the prism is irradiated with light. Since the refractive index or the dielectric constant is determined from the incident angle where the loss of plasmon resonance is large, it is difficult to reduce the size of the sensor part structurally, and a light source and detection for changing the incident angle at that time are required. There is a problem that a drive mechanism of the container is required, and the size of the sensor device cannot be avoided. In addition, in the optical coupling between the light source and the detector and the prism, there is also a problem that high-precision alignment is required in order not to lower the sensitivity of the sensor.

On the other hand, in the latter, the cladding at the end portion of the optical fiber is removed to expose a core made of glass, and the exposed core is coated with a metal thin film such as gold, and at the same time, the core of the optical fiber is exposed. A mirror made of silver or the like is provided at the end as a reflection surface, and light of multiple wavelengths is made incident on this optical fiber to measure the wavelength at which loss of surface plasmon resonance occurs and the amount of attenuation at that time. In order to increase the sensitivity, a considerably long optical fiber, for example, an optical fiber having a length of several centimeters, is required.In this case, there is a problem that it is difficult to reduce the size of the sensor unit. It must be composed of a light receiving device that detects reflected light, and a beam splitter that separates incident waves and reflected waves, resulting in an increase in the size of the sensor device. It made.

In addition, when manufacturing this type of sensor, the cladding at the end of the optical fiber is removed to expose a glass core, and the exposed core is coated with a thin metal film such as gold. However, when the cladding is removed and the core is coated with a metal thin film, the optical fiber is processed by rotating it around its optical axis. As a result, an error occurs in the wavelength measurement with respect to the resonance loss peak for obtaining the refractive index or the dielectric constant of the substance to be analyzed, so that the processing is not easy. Further, when an organic substance is attached to the metal thin film surface of the sensor section in order to provide the above-described optical fiber type surface plasmon resonance sensor with a function as a biosensor, the organic substance is attached to the cylindrical surface of the optical fiber sensor. Therefore, there is a problem that it is difficult to control the thickness of the organic material.

An optical waveguide type surface plasmon resonance sensor has been proposed from the viewpoint of miniaturization of the surface plasmon resonance sensor. However, in the conventional optical waveguide type surface plasmon resonance sensor, impurities are ion-implanted into glass. An embedded optical waveguide type surface plasmon resonance sensor in which a sensor is formed by embedding a core in a clad formed by covering the core with a metal thin film such as gold, and such a sensor is made of an inorganic material called glass. When manufacturing an optical waveguide consisting of a cladding and a core made of a system material, there are difficulties in terms of manufacturing such as the processing temperature of glass, and the method of ion-implanting impurities into glass has a multimode optical waveguide with a large core diameter. It is difficult to make a waveguide.
Therefore, in the optical waveguide surface plasmon resonance sensor as described above, in order to reduce the size, when considering the connection between the sensor unit formed of glass and other optical elements,
For example, it is difficult to align the waveguide portion of the sensor portion formed of glass with the light emitting and receiving elements, and if the connection accuracy is not good, light loss related to the connection portion increases,
There also arises a problem that the sensitivity of the sensor is lowered such as the S / N ratio is deteriorated.

In the above-described method of ion-implanting impurities into glass, the refractive index at the interface between the portion where the refractive index is increased by ion implantation and the portion where the refractive index is not changed without ion implantation is gentle. For example, it is difficult to make a mirror structure by diagonally cutting the core end face of the optical waveguide to totally reflect the incident light, or the refractive index difference between the core and the clad is extremely large. Because of the small size, the critical angle became large, and a mirror structure could not be constructed. In such a case, there is a problem that a mirror structure must be formed by depositing silver or the like on the end face of the core.

Further, in the optical waveguide type surface plasmon resonance sensor formed as described above, the sensor portion covered with the metal thin film is formed of a single linear portion as described above. In view of the characteristics of the sensor that the sensitivity is improved in accordance with the increase in the surface area of the sensor, if the sensitivity is to be improved, it is unavoidable to increase the length of the sensor portion, in other words, the sensor is inevitably increased in size, Conversely, if the sensor section is shortened in order to reduce the size of the sensor, that is, to reduce the size of the sensor, there is a problem that improvement in sensor sensitivity cannot be expected.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above-mentioned problems of the prior art, and has as its object to be compact, have good sensitivity, and have another optical element. The object is to provide a surface plasmon resonance sensor that can be easily optically connected to the device and is easy to manufacture. Another object of the present invention is to provide a surface plasmon resonance sensor that is compact, can achieve a significant improvement in sensitivity, facilitates optical connection with other optical elements, and is easy to manufacture. .

[0010]

The above object is achieved by a surface plasmon resonance sensor according to the present invention. That is, in summary, the present invention has an optical waveguide formed by sequentially laminating a clad layer and a core layer on a substrate,
A surface plasmon resonance sensor further comprising a sensor portion formed by providing a metal thin film on a surface of a core layer of the optical waveguide, wherein the core layer and the cladding layer of the optical waveguide are formed of a resin. A surface plasmon having a plasmon resonance sensor and an optical waveguide formed by sequentially laminating a clad layer and a core layer on a substrate, and further including a sensor portion formed by providing a metal thin film on the surface of the core layer of the optical waveguide. In a resonance sensor, a core layer and a clad layer of the optical waveguide are formed of resin, and a plurality of the sensor units are provided on one optical plane, and the plurality of sensor units are provided with light. A surface plasmon resonance sensor characterized in that it passes optically continuously and the length of the sensor portion is substantially increased.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A surface plasmon resonance sensor according to the present invention forms an optical waveguide by sequentially laminating a clad layer and a core layer made of a resin on a substrate such as a silicon substrate, and further forms a core of the optical waveguide. Since it is a surface plasmon resonance sensor having a sensor portion formed by providing a metal thin film such as gold on the surface of the layer, the core diameter of the waveguide made of resin can be easily increased, and the refractive index of the substance to be measured can be reduced. In the measurement, when optical connection is performed between the core layer of the sensor and other optical elements such as a light source and a detector, alignment of the optical connection is very easy, and is caused by poor alignment accuracy of the optical connection. There is no reduction in sensor sensitivity due to light loss. Further, the surface plasmon resonance sensor of the present invention can reduce the size of the sensor unit and the size of the entire sensor device as compared with a conventional prism type surface plasmon resonance sensor or optical fiber type surface plasmon resonance sensor. it can.

Moreover, since the cladding layer and the core layer of the optical waveguide of the surface plasmon resonance sensor of the present invention are formed of resin, it can be easily manufactured. Furthermore, the surface plasmon resonance sensor of the present invention forms an optical waveguide by sequentially laminating a clad layer and a core layer made of a resin on a substrate, and further forms a thin metal film such as gold on the surface of the core layer of the optical waveguide. A surface plasmon resonance sensor having a sensor unit formed by providing a plurality of sensor units on one optical plane, and light passes optically continuously through these plurality of sensor units. Since the length of the sensor section is substantially increased, in other words, the surface area of the sensor section is substantially increased substantially, so that the sensitivity of the surface plasmon resonance sensor can be greatly improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments with reference to the accompanying drawings. FIG. 1 is a perspective view of one embodiment of a surface plasmon resonance sensor according to the present invention, and FIG.
(A) thru | or (e) are process drawings at the time of producing the surface plasmon resonance sensor shown in FIG.

Referring to FIG. 1, there is shown a surface plasmon resonance sensor 1 according to a first embodiment of the present invention. This surface plasmon resonance sensor 1 facilitates optical connection with other optical elements. The substrate is provided with, for example, a semiconductive silicon substrate 2 having a side of 25 mm × 25 mm in order to facilitate modularization. On this silicon substrate 2, Teflon AF16, which is an amorphous fluororesin,
Cladding layer 3 of 00 (refractive index 1.31, manufactured by DuPont)
Is formed at a thickness of 6 μm, and a polymethyl methacrylate (hereinafter referred to as PMMA) core layer 4 (refractive index: 1.49) is formed at a substantially central portion on the cladding layer 3 formed on the silicon substrate 2. Are formed with dimensions of 5 μm in height, 5 μm in width, and 10 mm in length, and the clad layer 3 and the core layer 4 constitute a loaded optical waveguide 5. The surface of the core layer 4 of the optical waveguide 5 is coated with 40n of gold.
Metal coating 6 deposited and coated to a thickness of m (nanometers)
Are formed, and a portion where the metal film 6 is provided on the optical waveguide 5 is configured as a sensor unit 7.

A method of manufacturing the above-described optical waveguide type surface plasmon resonance sensor 1 will be described below with reference to FIGS. 2 (a) to 2 (e). First, for example, a silicon substrate 2 having a side of 25 mm × 25 mm
Is prepared and Florinert FC is placed on the silicon substrate 2.
Teflon AF1600 (8% solution) having a refractive index of 1.31 dissolved in -75 (manufactured by 3M) was dropped, and the silicon substrate 2 was rotated at 600 rpm using a spinner (not shown).
(Rotation speed per minute) for 20 seconds, Teflon A
An 8% solution of F1600 is applied on the silicon substrate 2.
This silicon substrate 2 was inserted into a hot air circulating drier (not shown) set at a temperature of 180 ° C. and left for 1 hour to dry and remove florinert as a solvent to remove Teflon AF1600 having a thickness of 6 μm. Form clad layer 3 (FIG. 2)
(A)).

Next, the surface of the clad layer 3 is surface-modified by dry etching to impart hydrophilicity, and a PMM having a refractive index of 1.49 is placed on the surface-modified clad layer 3.
A mixed solution of A and methyl methacrylate (hereinafter referred to as MMA) (a solution composed of 10% of PMMA and 90% of MMA) was dropped, and the mixed solution was dropped with a spinner (not shown). 4000 rpm for the silicon substrate 2
At a speed of 15 seconds, and apply a mixed solution of PMMA and MMA onto the cladding layer 3. The silicon substrate 2 coated with the mixed solution on the cladding layer 3 is heated at a temperature of 180 °.
Inserted into a hot air circulating dryer set at a temperature of C and dried by heating for 1 hour to form a PMMA core layer 4 (FIG. 2).
(B)). The dry etching conditions described above were a dry etching chamber pressure of 30 Pa (Pascal), an oxygen gas flow rate of 200 sccm (standard cubic centimeter per minute), a power of 200 W, and a time of 30 seconds.

Next, an electron beam lithography apparatus (not shown) is provided in a predetermined range of the core layer 4 so that the PMMA core layer 4 has a predetermined size and is left and formed substantially at the center of the silicon substrate 2. Irradiate with an electron beam, and thereafter, after development with a developer, rinsing with water, post-baking, and
A PMMA core layer 4 having a size of 10 μm, a width of 5 μm, and a length of 10 mm is formed.
Constitute the loading type optical waveguide 5 (FIG. 2C,
(D)). The electron beam irradiation conditions were as follows: an acceleration voltage of 20 KV, and a dose amount per square centimeter of 1
The post-baking was performed at a temperature of 170 ° C. for 20 minutes, with 00 μC (microcoulomb) and a current value of 1 × 10 minus 8 amps.

Thereafter, the PMM thus formed is formed.
On the surface of the core layer 4 of A, gold was deposited from both sides of the core layer 4 by a vacuum deposition apparatus (not shown) to form a metal thin film 6, thereby producing a sensor section 7 (see FIG. 2E). ). This film was formed by a resistance heating method, and was deposited until the film thickness became 40 nm.

The optical waveguide type surface plasmon resonance sensor 1 formed through the above-described process can easily increase the core diameter of the waveguide 5 made of resin as compared with a conventional glass plasmon resonance sensor using glass. When measuring the refractive index of a substance to be measured, the alignment of the optical connection is very easy even when the core layer 4 of the sensor 1 is optically connected to another optical element such as a light source and a detector. There is no decrease in sensor sensitivity due to light loss caused by poor alignment accuracy of the optical connection. In addition, the surface plasmon resonance sensor 1 can reduce the size of the sensor unit 7 and the size of the entire sensor device as compared with a conventional prism type surface plasmon resonance sensor or optical fiber type surface plasmon resonance sensor. it can. Moreover, the cladding layer 3 and the core layer 4 of the optical waveguide 5 of the surface plasmon resonance sensor 1 described above.
Is formed using a resin that can be formed and formed by using a process such as spin coating as described above. Therefore, compared to a conventional optical waveguide formed by ion-implanting impurities into glass, In addition, manufacturing difficulties such as a glass processing temperature can be greatly reduced, and the glass can be easily manufactured.

Next, a second embodiment according to the present invention will be described below. The second embodiment is substantially the same as the first embodiment described above, except that an amorphous fluororesin is used for the cladding layer 3 and the core layer 4. Teflon AF1600 (refractive index: 1.31, manufactured by DuPont), which is an amorphous fluororesin, is used as the resin of the organic polymer material for the upper cladding layer 3, and amorphous resin is used for the core layer 4 as the resin of the organic polymer material. CYTOP (refractive index: 1.34, manufactured by Asahi Glass Co., Ltd.) which is a fluororesin is used.

The method of manufacturing the surface plasmon resonance sensor 1 of the second embodiment is substantially the same as that of the first embodiment, and will be described below with reference to FIGS. 2 (a) to 2 (e). The same components will be described with the same reference numerals. First, as in the first embodiment, one side is 25 m.
A silicon substrate 2 of mX25 mm was prepared, and Teflon AF1600 having a refractive index of 1.31 dissolved on this silicon substrate 2 with Fluorinert FC-75 (manufactured by 3M).
(8% solution) is dropped, the silicon substrate 2 is rotated at a speed of 600 rpm for 20 seconds using a spinner, and the solution of Teflon AF1600 is applied onto the silicon substrate 2.
The silicon substrate 2 was inserted into a hot air circulating drier set at a temperature of 300 ° C. and heated for 1 hour to dry and remove the solvent florinert.
A cladding layer 3 of No. 00 is formed (see FIG. 2A).

Next, a solvent CT is formed on the cladding layer 3.
-Solv. 180 (manufactured by Asahi Glass Co., Ltd.), a CYTOP (8% solution) having a refractive index of 1.34 was dropped, and the silicon substrate 2 on which the solution was dropped was spin-dried with a spinner for 800 r.
The CYTOP solution is applied onto the cladding layer 3 by rotating the CYTOP solution at a speed of pm for 20 seconds. The silicon substrate 2 coated with the CYTOP solution on the cladding layer 3 is heated at a temperature of 300 ° C.
Insert into the hot air circulating dryer set at and heat for 1 hour,
The solvent is dried and removed to form the CYTOP core layer 4 (see FIG. 2B).

Next, the surface of the core layer 4 is surface-modified by dry etching to impart hydrophilicity, and a positive photoresist OFPR8600 is formed on the surface-modified core layer 4.
(Manufactured by Tokyo Ohka Kogyo Co., Ltd.), and 4
Spin at a speed of 000 rpm for 20 seconds to apply. The conditions for the dry etching were as follows: the dry etching chamber pressure was 30 Pa; the oxygen gas flow rate was 200 sccm;
Power 200W, time 30 seconds. The silicon substrate 2 thus coated with the photoresist on the core layer 4
Into a hot air circulating dryer set at a temperature of 80 ° C., and heated for 40 minutes to dry.

Thereafter, the silicon substrate 2 is taken out from the hot air circulating drier, the photoresist is irradiated with ultraviolet rays by an ultraviolet exposure device (not shown), further developed with a dedicated developer, rinsed with water, and washed at a temperature of 140 ° C. And post-baking for 20 minutes to form a photoresist core pattern. Dry etching of the core layer 4 is performed using the photoresist as an etching mask. The dry etching was performed at a power of 200 W for 20 minutes under an atmosphere of a chamber pressure of 45 Pa, an oxygen gas, a carbon tetrafluoride gas, and an argon gas. The photoresist is stripped with a dedicated stripping solution, and the CYTOP core layer 4 has a desired height of 10 μm, a width of 50 μm, and a length of 10 mm.
Are formed, and the clad layer 3 and the core layer 4 constitute a loaded optical waveguide 5 (see FIGS. 2C and 2D).

Thereafter, on the surface of the core layer 4 of the CYTOP thus formed, gold is formed from both sides of the core layer 4 by a vacuum evaporation apparatus to form a metal thin film 6, and the sensor section 7 is manufactured. (See FIG. 2E). This film was formed by a resistance heating method, and was deposited until the film thickness became 40 nm.

The optical waveguide type surface plasmon resonance sensor 1 of the second embodiment manufactured in this manner can easily increase the core diameter of the waveguide 5 made of resin similarly to the first embodiment, and can be measured. When measuring the refractive index of the material to be
Even when the core layer 4 of the sensor 1 is optically connected to another optical element such as a light source and a detector, the alignment of the optical connection is very easy, and the light loss caused by the poor alignment accuracy of the optical connection causes the loss. There is no decrease in sensor sensitivity.
In addition, the surface plasmon resonance sensor 1 can also reduce the size of the sensor unit 7 and the size of the entire sensor device as compared with a conventional prism type surface plasmon resonance sensor or optical fiber type surface plasmon resonance sensor. it can. Moreover, as in the above-described embodiment, the cladding layer 3 and the core layer 4 of the optical waveguide 5 of the surface plasmon resonance sensor 1 are formed of a resin that can be formed and formed by using a process such as spin coating as described above. In comparison with a conventional optical waveguide formed by ion-implanting impurities into glass, when manufacturing the optical waveguide 5, it is possible to greatly reduce manufacturing difficulties such as a processing temperature of the glass, and to easily manufacture the optical waveguide. In addition, since these resins are all fluororesins, they have excellent chemical resistance and heat resistance.

Next, a third embodiment according to the present invention will be described below. The third embodiment is almost the same as the first and second embodiments described above, but as shown in FIG.
A lower cladding layer 3 on the silicon substrate 2 and two side cladding layers 33 on the lower cladding layer 3;
Grooves 32 formed between these side cladding layers 33
A sensor layer 7 is formed by forming a metal thin film 6 on the surface of the core layer 4.
For the cladding layers 3 and 33, a photosensitive resin of SU-8 (refractive index: 1.38, mainly composed of bisphenol novolak glycidyl ether; manufactured by MicroChem Corp., USA) is used as a resin of an organic polymer material. And the core layer 4 is mainly made of PMMA.

A method of manufacturing the surface plasmon resonance sensor 1 according to the third embodiment will be described below with reference to FIGS. 4A to 4E. The method is the same as or similar to the first and second embodiments. Will be described with the same or similar reference numbers. First, as in the first and second embodiments, a silicon substrate 2 having a side of 25 mm × 25 mm is prepared, and SU-8 is placed on the silicon substrate 2.
Is dropped, and the silicon substrate 2 on which the solution is dropped is rotated at a speed of 2000 rpm for 15 seconds using a spinner, and the SU-8 solution is applied onto the silicon substrate 2. The silicon substrate 2 thus coated with the SU-8 solution
Was inserted into a hot-air circulating dryer set at a temperature of 70 ° C., heated for 10 minutes, further heated at a temperature of 90 ° C. for 1 hour, and then irradiated with ultraviolet light by an ultraviolet exposure device (not shown). After further heating at a temperature of 100 ° C. for 60 minutes,
A lower cladding layer 3 of SU-8 having a thickness of 100 μm is formed (see FIG. 4A).

Next, on the silicon substrate 2 on which the lower cladding layer 3 has been formed, SU-8
Is dropped, and the silicon substrate 2 on which the solution is dropped is rotated at a speed of 2000 rpm for 15 seconds using a spinner, and the SU-8 solution is applied onto the silicon substrate 2. The silicon substrate 2 on which the SU-8 solution was further applied on the lower clad layer 3 was inserted into a hot air circulating dryer set at a temperature of 70 ° C. and heated for 10 minutes.
After further heating at a temperature of 90 ° C. for 1 hour, irradiation with ultraviolet light was performed using an ultraviolet exposure apparatus.
After heating for one minute, a side cladding layer 31 of SU-8 having a thickness of 100 μm is formed (see FIG. 4B).

Next, the side cladding layer 3 of the SU-8
1, as shown in FIG. 4C, a groove 32 is formed substantially at the center of the side cladding layer 31 on the silicon substrate 2, and protrusions 33 are formed on both sides of the groove 32. UV light is irradiated by an ultraviolet light exposure device (not shown) in a predetermined range so as to remain and have a predetermined size by heating and further heated at a temperature of 90 ° C. for 30 minutes, and then developed with a developing solution. And by rinsing, a height of 100
The protrusions 33 of SU-8 having a vertical wall of μm, that is, side cladding layers 33 are formed on both sides of the groove 32 (see FIG. 4C).

The groove 32 formed between the side cladding layers 33 made of SU-8 has a P of 1.49 in refractive index.
A mixed solution of MMA and MMA is dropped and applied. The silicon substrate 2 having the groove 32 coated with the mixed solution of PMMA is inserted into a hot-air circulating dryer set at a temperature of 180 ° C. and dried by heating for 1 hour.
To form The lower clad layer 3, the side clad layer 33 and the core layer 4 constitute an optical waveguide 5 (FIG. 4).
(D)).

Thereafter, the PMM thus formed is formed.
A gold thin film was formed on the surface of the core layer 4 of A by a vacuum evaporation apparatus to form a metal thin film 6, and a sensor unit 7 was manufactured.
(E)). This film formation is performed by a resistance heating method,
Deposition was performed until the film thickness became 40 nm.

The optical waveguide type surface plasmon resonance sensor 1 of the third embodiment manufactured in this manner can easily increase the core diameter of the waveguide 5 made of resin similarly to the first and second embodiments. When measuring the refractive index or the like of a substance to be measured, the alignment of the optical connection is very high even when the core layer 4 of the sensor 1 is optically connected to another optical element such as a light source and a detector. It is easy and does not cause a decrease in sensor sensitivity due to light loss caused by poor alignment accuracy of the optical connection. In addition, this surface plasmon resonance sensor 1
Also, as compared with the conventional prism type surface plasmon resonance sensor or optical fiber type surface plasmon resonance sensor, the sensor unit 7 can be made more compact and the entire sensor device can be made smaller. Moreover, similarly to the above-described embodiment, the resin capable of forming and forming the lower cladding layer 3 and the side cladding layer 33 of the optical waveguide 5 of the surface plasmon resonance sensor 1 by using the process such as the spin coating as described above. Therefore, compared to the conventional optical waveguide formed by ion-implanting impurities into glass, when manufacturing the optical waveguide 5, manufacturing difficulties such as the processing temperature of the glass can be greatly reduced, and the glass can be easily formed. Can be made.

Further, in addition to the above-described embodiment according to the present invention, a fourth embodiment according to the present invention will be described below. In the surface plasmon resonance sensor 1 of the fourth embodiment, the same or similar components as those of the first to third embodiments described above are denoted by the same or similar reference numerals. As shown in FIGS. 5 and 6, the fourth embodiment differs from the first and second embodiments in that the metal thin film 6 covers the cladding layer 3, the core layer 4, and the surface of the core layer 4. Then, the formed sensor part 7 is formed to a desired length, and two or three or more (in this embodiment, a plurality of) sensor parts 7 formed to the desired length are formed on one optical plane. The four sensor units 7a, 7b, 7c, 7 from the upper side of FIG.
d), for example, the surface plasmon resonance sensor 1 is arranged side by side. More specifically, core layers 4a, 4b, 4c and 4d are formed on clad layer 3 having a predetermined range of area formed on silicon substrate 2.
Is formed, and the cladding layer 3 and these core layers 4a, 4a
b, 4c and 4d, respectively, the loaded optical waveguide 5
a, 5b, 5c and 5d.

At this time, one end face 10 of the core layer 4a is formed.
Are formed on an inclined surface having an angle of total reflection, for example, at an angle of 45 degrees, and the corresponding core is formed so as to have an optical mirror relationship with one end face portion 10 of the core layer 4a. One end face 11 of the layer 4b is also formed with a 45-degree slope, and the other end face 12 of the core layer 4b is
It is formed on a slope of 5 degrees. Similarly, the other end surface portion 13 of the core layer 4c corresponding to the other end surface portion 12 of the core layer 4b is also formed with a 45-degree slope, and the one end surface portion 14 of the core layer 4c also has a 45-degree slope. While being formed on a slope, one end face 15 of the core layer 4d is also formed with a 45-degree slope. The optical mirror relationship described above is based on the fact that the clad layer 3 and the core layer 4 made of the resin according to the present invention cause the difference in the refractive index of the resin used at each end face of the optical waveguide 5 to be smaller than the clad layer 3. And it is easily achieved by being clearly formed at the boundary surface of the core layer 4.

The core layers 4a, 4b,
4c and 4d, while covering the respective end faces 10 to 15;
The cladding layer 3 and the core layers 4a, 4b, 4c, 4d are exposed so as to expose the respective central portions of the core layers 4a, 4b, 4c and 4d.
Further, on top of c and 4d, for example, Teflon AF1600, PMMA or SU-8, which is an amorphous fluororesin,
A coating layer 16 of a suitable resin such as is provided on a predetermined region by a spin coating method. At that time, the core layers 4a, 4b,
The core layers 4a, 4b, 4c and 4d and the cladding layer 3
A seal or the like (not shown) is previously applied to a portion of each central portion to be exposed, and then the cladding layer 3 and the core layer 4 are exposed.
a, 4b, 4c, and 4d are coated by spin-coating a suitable resin to be the coating layer 16, and after this coating, the seals and the like are removed. You.

As a result, the core layers 4a, 4b, 4c and 4d, that is, the respective central portions of the optical waveguides 5a, 5b, 5c and 5b are exposed, and the periphery thereof is covered by the covering layer 16. In each of the end faces 10 to 15 of the core layers 4a, 4b, 4c and 4d, light can be continuously passed through these core layers without affecting the mutual optical mirror state. Become. The spin coating was performed at 1000 rpm for 20 seconds, followed by drying in an oven at 300 ° C. for 45 minutes. The coating layer 1 formed by the spin coating method
The formation of 6 may be repeated a desired number of times, if necessary, up to a predetermined thickness. Thereafter, gold is formed on the surfaces of the core layers 4a, 4b, 4c, and 4d exposed at the window 17 by a vacuum evaporation apparatus (not shown), and the metal thin films 6a, 6b, 6c, and 6d was formed, and sensor portions 7a, 7b, 7c, and 7d were respectively manufactured.

In the surface plasmon resonance sensor of the fourth embodiment configured as described above, when measuring the refractive index and the like of the substance to be measured, FIG. 7 is a schematic diagram illustrating the optical path of the surface plasmon resonance sensor. As will be easily understood from the reference, when light is incident from the other end face of the sensor section 7a, the light path passes through the sensor section 7a due to an optical mirror relationship, and the optical path is changed to one end face section 10a. Is reflected by the sensor part 7b by one end face part 11 of the sensor part 7b.
, Further reflected by the other end surface 12 of the sensor portion 7b, passed through the sensor portion 7c by the other end surface portion 13 of the sensor portion 7c, and further passed through one end surface portion 14 of the sensor portion 7c.
Then, the light passes through the sensor portion 7d by one end surface portion 15 of the sensor portion 7d and travels toward the other end surface portion of the sensor portion 7d.

This means that the optical path becomes longer, the surface area of the sensor portion of the surface plasmon resonance sensor is increased substantially, and the surface area of the sensor portion of the surface plasmon resonance sensor is substantially increased. In addition to the effects of the embodiments to the third embodiment, the sensitivity of the surface plasmon resonance sensor can be greatly improved by making it compact. In this case, in the conventional method of ion-implanting impurities into glass, as described above, it is difficult to cut the core end face of the optical waveguide obliquely to form a mirror structure in order to totally reflect incident light. The mirror structure can be formed by a very simple method as compared with the case where silver or the like is deposited on the core end surface to form the mirror structure.

It should be noted that the above-described fact is that even if the substance to be measured is non-translucent, the coating layer 16 covers the end faces of the core layers 4a, 4b, 4c and 4d. The light passes without affecting the mutual optical mirror state of the core layers 4a, 4b, 4c and 4d, in other words, without affecting the light passing from the sensor sections 7a to 7d. As a result, also in this case, the surface area of the surface plasmon resonance sensor unit can be substantially increased substantially. Although the above embodiment has been described in relation to the first and second embodiments, also in the third embodiment, a plurality of sensor units of the surface plasmon resonance sensor are provided, and these sensor units are provided with incident light. Needless to say, a similar effect can be obtained by adopting a configuration in which the transmitted light passes optically continuously and the length of the sensor portion can be substantially increased.

Although the above-described optical path has been described with reference to the case where the end face of the sensor section 7 is formed with a 45-degree slope, the present invention is not limited to this embodiment. 7b, the optical path is made longer by changing the slope angle of the end face and the arrangement of the sensor section 7 so that the length of the sensor section can be substantially increased. Means may be provided.

[0042]

As described above, according to the surface plasmon resonance sensor of the present invention, the core diameter of the waveguide made of resin can be easily increased, and the refractive index of the substance to be measured can be measured. In optical connection between the core layer of the sensor and other optical elements such as a light source and a detector, alignment of the optical connection is very easy, and the sensor due to light loss caused by poor alignment accuracy of the optical connection. There is no decrease in sensitivity. Further, the surface plasmon resonance sensor of the present invention can reduce the size of the sensor unit and the size of the entire sensor device as compared with a conventional prism type surface plasmon resonance sensor or optical fiber type surface plasmon resonance sensor. it can. In addition, when forming the clad layer and the core layer of the optical waveguide of the surface plasmon resonance sensor of the present invention, these can be easily manufactured because they are formed of resin.

Further, a plurality of sensor portions formed by providing a metal thin film on the surface of the core layer of the optical waveguide constituted by the clad layer and the core layer are formed on one optical plane.
In the disposed surface plasmon resonance sensor of the present invention, light passes optically and continuously through these plurality of sensor units, and the length of the sensor unit is substantially increased. Sensitivity can be greatly improved.

[0044]

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of a surface plasmon resonance sensor according to the present invention.

FIG. 2 (a) to

FIG. 2 (e) is a view showing the step of producing the surface plasmon resonance sensor shown in FIG. 1;

FIG. 3 is a plan view of another embodiment of the surface plasmon resonance sensor according to the present invention.

FIG. 4A to FIG.

FIG. 4 (e) is a view showing the step of producing the surface plasmon resonance sensor shown in FIG. 3;

FIG. 5 is a plan view of still another embodiment of the surface plasmon resonance sensor according to the present invention.

FIG. 6 is a sectional view of the surface plasmon resonance sensor shown in FIG.
It is sectional drawing which follows a line.

7 is a schematic diagram illustrating an optical path of the surface plasmon resonance sensor shown in FIG.

[Explanation of symbols]

 1: Surface plasmon resonance sensor, 2: Silicon substrate 3: Cladding layer, 4, 4a, 4b, 4c, 4d: Core layer 5, 5a, 5b, 5c, 5d: Optical waveguide 6, 6a, 6b, 6c, 6d: Metal thin film 7, 7a, 7b, 7c, 7d: sensor part 10, 11, 12, 13, 14, 15: end face part 16: coating layer 17: window

[Procedure amendment]

[Submission date] April 14, 2000 (2004.1.
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a perspective view of one embodiment of a surface plasmon resonance sensor according to the present invention.

FIGS. 2 (a) to 2 (e) are process diagrams for producing the surface plasmon resonance sensor shown in FIG.

FIG. 3 is a plan view of another embodiment of the surface plasmon resonance sensor according to the present invention.

4 (a) to 4 (e) are process diagrams for producing the surface plasmon resonance sensor shown in FIG. 3;

FIG. 5 is a plan view of still another embodiment of the surface plasmon resonance sensor according to the present invention.

FIG. 6 is a sectional view of the surface plasmon resonance sensor shown in FIG.
It is sectional drawing which follows a line.

7 is a schematic diagram illustrating an optical path of the surface plasmon resonance sensor shown in FIG.

[Description of Signs] 1: surface plasmon resonance sensor, 2: silicon substrate, 3: cladding layer, 4, 4a, 4b, 4c, 4d: core layer, 5, 5a, 5b, 5c, 5d: optical waveguide, 6, 6a, 6b, 6c, 6d: metal thin film, 7, 7a, 7b, 7c, 7d: sensor part, 10, 11, 12, 13, 14, 15: end face part, 16: coating layer, 17: window.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomonori Sasaki 3-13-10 Nishigaoka, Kita-ku, Tokyo Inside the Tokyo Metropolitan Industrial Research Institute (72) Inventor Genro Imaizumi 25-25-25 Miyasaka, Setagaya-ku, Tokyo No. Stock Company Junko F-term (reference) 2G059 AA01 AA05 BB04 BB12 CC20 DD13 EE02 GG00 JJ17 KK01 LL03

Claims (2)

[Claims] A clad layer and a core layer are sequentially formed on a substrate.
A surface plasmon resonance sensor having an optical waveguide formed by lamination and further including a sensor portion formed by providing a metal thin film on the surface of a core layer of the optical waveguide, wherein the core layer and the cladding layer of the optical waveguide are A surface plasmon resonance sensor formed of a resin. 2. A clad layer and a core layer are sequentially formed on a substrate.
A surface plasmon resonance sensor having an optical waveguide formed by lamination and further including a sensor portion formed by providing a metal thin film on the surface of a core layer of the optical waveguide, wherein the core layer and the cladding layer of the optical waveguide are A plurality of the sensor portions are formed on a single optical plane, and are formed of resin, and light passes optically continuously through the plurality of optical waveguides,
A surface plasmon resonance sensor, wherein the length of the sensor portion is substantially increased.