JP2002311236A - Variable wavelength interference optical filter, production method therefor and variable wavelength interference optical filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable wavelength interference optical filter, with which a wavelength can be arbitrarily selected without depending on a polarization plane, as the interference optical filter of a narrow band for selecting the wavelength by separating a specified wavelength component of incident light. SOLUTION: A multilayer film 3 is formed on a substrate 2 by deposition. The multilayer film 3 is composed of a lower multilayer film 31, a cavity layer 32 and an upper multilayer film 33. The upper and lower multilayer films 31 and 33 are respectively formed by alternately laminating high refractive index layers 31H and 33H and low refractive index layers 31L and 33L. Then, in the x-axis direction of the substrate 2, the refractive index thereof is continuously changed so that a wavelength can become λ/4n corresponding to a transmission wavelength λ. Thus, the transmission wavelength λ is continuously changed corresponding to the incident position of light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a narrow-band tunable interference optical filter used for optical communication, optical measurement, optical information processing, and the like, and depends on a polarization plane capable of continuously changing its transmission wavelength. The present invention relates to a wavelength tunable interference light filter, a method of manufacturing the same, and a wavelength tunable interference light filter device.

[0002]

2. Description of the Related Art A narrow-band optical filter having a dielectric multilayer film is conventionally used as a wavelength-variable filter in which a wavelength is continuously changed in a narrow-band optical filter. Such an optical filter is made of a high refractive material such as ZnS on a substrate, as shown in, for example, "Laser & Optics Guide II", Kino Melles Griot Co., Ltd., PP11-25 to 11-29 "Interference Filter". And Na ₃ AlF
A low-refractive-index material such as ₆ is alternately multilayer-coated with an optical thickness of exactly 1/4 wavelength. Here, assuming that the transmission wavelength is λ and the refractive index of each layer is n, the optical thickness nd is represented by λ / 4. By forming such a multilayer coating layer on a substrate, a narrow band optical filter can be realized.

Conventionally, in an interference optical filter in which dielectric films are laminated in a multilayer to continuously change a transmission wavelength, an optical wavelength tunable filter in which the film thickness of each layer is continuously changed in a predetermined direction has been proposed. (Japanese Patent Application Laid-Open No. 5-2814)
No. 80).

[0004]

However, as shown in FIG. 15, in such a wavelength tunable filter 101 that continuously changes the thickness of the dielectric multilayer film, a transparent substrate 102 serving as a base and a dielectric multilayer film are formed. The plane 103 is no longer parallel. For this reason, the wavelength-division multiplexed light is incident on the dielectric multilayer filter 101 to move the filter in the direction in which the film thickness changes, and the add and the add add only a predetermined wavelength from the optical signal multiplexed by the transmitted light and the reflected light. When a drop for extracting a predetermined wavelength is performed, FIG.
As shown in (b), the distance to the light reflection surface varies depending on the incident position, and thus the efficiency is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and has been made in view of the above circumstances. A wavelength variable interference light filter having a surface parallel to a substrate without changing the position of reflected light depending on the incident position. And a method of manufacturing the same and an interference light filter device.

[0006]

According to the first aspect of the present invention, there is provided a wavelength tunable interference optical filter for continuously changing light transmitted in a predetermined wavelength range. A substrate formed of a material to be formed, and a first refractive index n formed on the substrate.
₁ , a first deposited material film having a thickness d _{1 and} a second deposited material film having a second refractive index n ₂ having a refractive index lower than n ₁ and a thickness d ₂ are alternately laminated to form a multilayer deposited material film. Wherein the refractive indexes n ₁ and n ₂ of the multilayer vapor-deposited material film continuously change along a predetermined direction of the substrate, and irradiation of the optical filter with incident light is performed. The wavelength of the transmitted light is changed by changing the position along a predetermined direction of the substrate.

According to a second aspect of the present invention, in the wavelength tunable interference optical filter of the _{first aspect} , the thickness of each layer of the multilayer deposited material film is d ₁ and d ₂ , and the transmission wavelength at that position is λ. Then, the refractive index of each film continuously changes so that d ₁ = λ / 4n ₁ and d ₂ = λ / 4n ₂ , respectively.

The invention of claim 3 of the present application is directed to claim 2 or 3
In the wavelength-tunable interference optical filter, the deposition material layer is characterized in that the thickness d ₃ between the multilayer film is constructed by inserting a cavity layer of lambda / 2n _1.

According to a fourth aspect of the present invention, in the tunable interference light filter of the first aspect, the tunable interference light filter is formed on a rectangular plate-like substrate, and its longitudinal direction is The refractive index of the deposition material film is changed continuously along the line.

According to a fifth aspect of the present invention, in the variable wavelength interference light filter of the first aspect, the wavelength variable interference light filter is formed on a disk-shaped substrate. Things.

According to a sixth aspect of the present invention, there is provided a wavelength tunable interference light filter according to any one of the first to fourth aspects, a first collimator for converting light from a light source into parallel light, A second collimator disposed to face the first collimator and condensing a light beam; and a second collimator disposed between the first and second collimators, the second collimator being arranged in a direction in which a refractive index of the wavelength variable interference optical filter changes. Moving means for moving the wavelength variable interference light filter.

According to a seventh aspect of the present invention, there is provided a wavelength tunable interference light filter according to any one of the first to fourth and sixth aspects, a first collimator for converting light from a light source into parallel light,
A second collimator disposed to face the first collimator and condensing a light beam; and a change direction of a refractive index of the wavelength variable interference light filter disposed between the first and second collimators. And rotating means for rotating the variable wavelength interference light filter.

According to the invention of claim 8 of the present application, a substrate is disposed on a rotating dome, which is provided in a vacuum chamber and has an open surface, perpendicularly to a rotation axis of the rotating dome, and an electrode is provided on a back surface thereof. A first evaporation source having a first refractive index and a second evaporation source having a second refractive index are arranged in the vacuum chamber, and a voltage is applied between the electrode and the vacuum chamber. The electric field changes the density of plasma formed in the vicinity of the substrate, and alternately evaporates the first and second evaporation sources while rotating the rotating dome at a predetermined speed, and has a predetermined film thickness. , And are alternately deposited and laminated.

According to a ninth aspect of the present invention, in the manufacturing method of the tunable interference light filter of the eighth aspect, the electrodes used for forming the plasma are radially arranged from the center of rotation of the substrate toward the peripheral direction. The density is changed.

According to the present invention having such features,
By changing the refractive index of the multilayer vapor deposition material film continuously according to the transmission wavelength, a multilayer wavelength variable interference light filter is configured. For this reason, in the direction of change in the refractive index, the light selection characteristic changes depending on the light irradiation position. In this case, the wavelength continuously changes even if the irradiation position of the light is changed, but the full width at half maximum, the position of the incident light, the position of the reflected light, etc. do not change,
Further, characteristics independent of the polarization plane can be obtained.

[0016]

FIG. 1 is a diagram showing the configuration of a polarization-independent type wavelength-variable interference light filter according to a first embodiment of the present invention. The tunable interference light filter 1 according to the present embodiment is configured by depositing a plurality of substances on a substrate 2 such as glass or silicon. The substrate 2 is made of a material having a high light transmittance in a wavelength range to be used, and a dielectric or a semiconductor is used. In this embodiment, quartz glass is used. Then, on the upper portion of the substrate 2, a multilayer film 3 of a deposition material, a dielectric, a semiconductor, or the like having a high light transmittance at a wavelength to be used is deposited. Here, the multilayer film 3 is composed of a lower multilayer film 31, a cavity layer 32 and an upper multilayer film 33 as shown in the figure.
Shall be formed from An antireflection film 4 is formed on the lower surface of the substrate 2 by vapor deposition. The antireflection film is a two-layer film of, for example, SiO ₂ and TiO ₂ , but may be a film using only one of them.

Here, the vapor deposition material of the multilayer film 3 and the antireflection film 4
The substance used as is, for example, SiO_Two(Refractive index n =
1.46), Ta_TwoO_Five(N = 2.15), Si (n = 3.46) or A
l_TwoO _Three, Si_TwoN_Four, MgF, etc. are used. In addition,
In the embodiment, the multilayer film 3 has a low refractive index film and a high refractive index film alternately.
Laminated and deposited. Here, the thickness of the high refractive index film
d ₁, Low refractive index film thickness d_TwoAnd transmission wavelength λ, high refractive index film
Refractive index n₁, The refractive index n of the low refractive index film_TwoIs related to
So that n₁d₁= Λ / 4 n_Twod_Two= Λ / 4 (1) where the optical thickness of each layer is n₁d₁Or n_Twod_TwoRepresented by
You. And alternately stack low and high refractive index films
The full width at half maximum of the transmittance peak (FWHM)
Is smaller.

In the tunable interference light filter 1 according to the present embodiment, since the transmission wavelength and the film thickness have the relationship of the equation (1), the substrate 2 is formed as an elongated plate-like substrate, The refractive index of the multilayer film 3 is changed slightly continuously to change the transmission wavelength λ. D
₁ and d ₂ are constant regardless of the position. Then, the transmission wavelength of the tunable interference light filter 1 is defined as λ _a to λ _c (λ
_a <λ _c ), and the transmission wavelength at the center point (x = x _b ) is λ _b . In such a wavelength tunable interference light filter, the upper and lower multilayer films 31 and 33 have the first refractive index n ₁ ,
More precisely, the first deposited material films of n _{1a to} n _1c and the second refractive index n ₂ having a lower refractive index, more precisely n _2a to n _2c .
The second deposition material film of n _2c (n _1a , n _1c > n _2a , n _2c ) is alternately laminated. In FIG. 1B, the lower multilayer film 31 has a low refractive index film of 31L and a high refractive index film of 31H.
The high refractive index film of the upper multilayer film 33 is set to 33H, and the low refractive index film is set to 33L. And Figure 1 end x _a of each low refractive index film the transmission wavelength against lambda _a and the high refractive index film in the above equation on the x-axis of the filter (a) (1) is set so that holds . The x _b, to set the transmission wavelength lambda _b, lambda the wavelength lambda _b, lambda its refractive index as equation (1) holds in _c against _c at x _c. The refractive index during that period is also set so that the change in wavelength changes linearly. Accordingly, the thickness of each layer is the same for each high refractive index film and each low refractive index film, but each refractive index changes continuously as the position x _{a to} x _c on the x axis, and the positive direction of the x axis The refractive index increases toward. Therefore, assuming that the film thickness is d, the wavelength λ is a function λ (x) of x, and the refractive index is a variable n (x) of x, these relations are λ (x).
(X) / 4 = n (x) · d.

On the quartz glass substrate 2, SiO ₂ is alternately laminated as the low refractive index films 31L and 33L, and TiO ₂ is laminated as the high refractive index films 31H and 33H.
In a filter having a single cavity structure having a center wavelength of 1550 nm, a narrow band filter having a full width at half maximum (FWHM) of 1 nm or less was realized when the upper and lower multilayer films 3 were combined into 32 layers or more. In addition, Si on the quartz glass substrate 2
In a filter having a single cavity structure in which O ₂ and Si are stacked, a total of 24 layers including the upper and lower multilayer films 3 are stacked to realize a narrow band filter having a full width at half maximum (FWHM) of 1 nm or less. As described above, as the difference between the refractive indices of the high refractive index film and the low refractive index film increases, a narrow band filter can be realized with a smaller number of film layers.

FIG. 2 shows the change of the transmission wavelength λ, the full width at half maximum and the change of the transmittance with respect to the incident position x of the light with respect to the wavelength tunable interference optical filter of the present embodiment. Even when the incident position x is changed and the transmission wavelength λ is changed linearly in the equation (1), the full width at half maximum and the transmittance do not change according to the position on the x-axis, but become a constant value. It is shown. Also, there is no difference in the polarization plane of the incident light, and a narrow band optical filter independent of the polarization plane can be realized.

In the above-described embodiment, the wavelength variable interference light filter having a single cavity structure is described. However, a multi-cavity filter having a plurality of such cavity layers may be used. For example, the upper multilayer film 33 having the single cavity structure according to the above-described embodiment.
A tunable interference light filter having a double-cavity structure in which a cavity layer is further formed on the upper surface and a multilayer film is formed on the cavity layer. In this case, as shown in FIG. 3, even if the number of multilayer films is reduced, the wavelength selectivity can be improved. In this figure, m indicates the change in the number of cavities and the wavelength selection characteristics when the same number of multilayer films are used. As is clear from the figure, the wavelength selection characteristic is improved as the number of cavities increases.

As shown in FIG. 4, such a wavelength tunable interference optical filter is used by irradiating one end of the optical filter with light, for example, white light, and separating a spectral component of a desired wavelength. In FIG. 4, light enters the wavelength-tunable interference light filter via the optical fiber 11 and the lens 12 and receives light transmitted through the condenser lens 13 and the optical fiber 14. And this optical filter 1 is x
It is assumed that the wavelength λ to be selected is changed by moving in the axial direction. If the wavelength tunable interference light filter 1 is slightly tilted, for example, by 3 ° to 7 ° as shown in FIG.
Light reflected on the front of the wavelength tunable interference light filter 1 is not reflected directly on the light source side, and adverse effects on the light source side can be avoided. It is necessary that this inclination angle be in a range where the polarization dependence is not present, for example, 10 ° or less.

FIG. 5 shows a manually tunable interference light filter device in which a single wavelength light is separated from incident light by using the tunable interference light filter and the separated wavelength is continuously changed. It is a perspective view which shows the specific example of. In this drawing, a base 21 is a frame having a U-shaped cross section, and a collimating linker 22 is disposed on a pedestal inside thereof.
The collimating linker 22 is a component for outputting light incident from the optical fiber 23 as parallel light. The light incident from the optical fiber 23 is incident on the tunable interference light filters 1A and 1B described above. As described above, the tunable interference light filters 1A and 1B are each inclined at a predetermined angle with respect to the incident light, and the irradiation positions thereof are continuously changed by the adjusters 24 and 26. Here, two adjacent adjusters 24, 2
Numeral 6 is a rack and pinion system, and the knobs are rotated to move the variable wavelength interference light filters 1A and 1B independently and precisely in the x direction in the figure. This movement position is determined by scales 25 and 27 provided on the adjuster.
For example, it is assumed that accurate reading can be performed with an accuracy of about 10 μm. An optical fiber 29 for output is connected to a position facing the collimator linker 22 via a collimator linker 28 on the base. Here, the collimator linkers 22 and 28 are first and second collimators for collimating the light beam from the light source and condensing the light beam, respectively. It constitutes a moving means for moving in the direction.

In this way, the light incident from the optical fiber 23 passes through the tunable interference light filters 1A and 1B via the collimator linker 22, and is again transmitted to the collimator linker 28.
Is output from the optical fiber 29 via the Here, even if the light incident from the optical fiber 23 has a spectrum covering a wide wavelength as shown in FIG. 6A, a specific wavelength as shown in FIG. Is selected and emitted from the optical fiber 29. The selected wavelength can be continuously changed by the adjusters 24 and 26. Here, by sequentially switching the filters to be used by using the two adjusters and the optical filter, the wavelength change range can be increased, and the width of the selected wavelength can be improved as a whole of the wavelength tunable interference optical filter device. For example, the selection wavelength of the variable wavelength interference light filter 1A is set to 1500 nm.
1520 nm and 1B are selected as 1520 nm to 1540 nm. Then, the relationship between the position and the wavelength is preliminarily incident on the optical fiber 23 using a light source whose wavelength is known, and when the output is obtained, the light of that wavelength is clearly indicated on the scale as being selected. If calibration is performed at a number of rotational positions of the knob in this manner, an arbitrary wavelength can be selected based on this scale even when a light source whose incident wavelength is unknown is used.

In this embodiment, the adjusters 24 and 2
Although the position is manually adjusted by the step 6, it goes without saying that the transmission position of the interference light filter may be changed electrically using a motor. Further, in this embodiment, the width of the selected wavelength is improved by switching the wavelengths to be used by using two tunable interference light filters. However, one filter may be used, and more filters may be used. It goes without saying that it may be used. If a plurality of filters having the same characteristics are arranged in parallel and moved in the same direction so that their center wavelengths always coincide, the wavelength selectivity can be improved without using a multi-cavity structure.

In the above-described embodiment, the shape of the filter is a rectangular plate-like filter. However, the filter may be formed using a circular filter. FIG. 7 shows a disk-shaped variable wavelength interference light filter 41 in which a multilayer film 43 and a reflection film 44 are formed on a disk-shaped substrate 42. Also in this case, in FIG. 7, each refractive index is configured to change continuously in proportion to the position in the x-axis direction. In this case, FIG.
As shown in (a) to (c), the transmission wavelength is proportional to cos θ when the position is represented by the angle θ with respect to the origin of the x-axis. Therefore, when the circular filter is rotated, it changes continuously as shown in the figure. Also in this case, the full width at half maximum and the transmittance are determined by the rotation angle (c
os θ or θ) and is constant.

FIG. 9 is a perspective view showing the state of use of such a circular variable wavelength interference light filter. In this figure, the light incident through the optical fiber 11 is incident on the tunable interference light filter 41 as parallel light through the collimator lens 12 as in the usage example of FIG. The transmitted light is received by the optical fiber 14 via the condenser lens 13. Here, the tunable interference light filter 41 is rotated in the direction of the arrow by using rotating means (not shown), for example, a motor or a crank-type knob and a reduction mechanism. Then, the wavelength is selected according to the rotation angle. In this case, a wavelength linearized in proportion to cos θ instead of the rotation angle θ is selected. Therefore, if the rotation angle and the selected wavelength are measured in advance, a desired wavelength can be selected.

As described above, if the wavelength tunable interference light filter is formed in a circular shape and the refractive index of the multilayer film 43 is continuously changed depending on the position in the x-axis direction as shown in FIG. The wavelength range can be selected by rotating the optical filter between semicircles, ie, 180 °. Therefore, two circular wavelength tunable interference optical filters having different selected wavelength ranges are stuck together as shown in FIG.
1A and 41B can also be used. In this case, if the selected wavelengths are made different from each other, as shown in FIG.
There is no need to switch the number of optical filters, and a wide range of wavelength selection characteristics can be obtained. Further, as shown in FIG. 10B, a larger number of tunable interference light filters 41A are provided.
To 41D.

In the above-mentioned circular wavelength-tunable interference light filter, the refractive index of the multilayer deposited material film is continuously changed depending on the position in the x-axis direction. It is also possible to adopt a configuration in which the film thickness is continuously changed. In this case, a wavelength characteristic corresponding to the rotation angle θ is obtained.

Next, a method of manufacturing the interference filter used in each of the above-described embodiments will be described. In the filter 1 of the present embodiment, it is necessary to continuously change the refractive index of the multilayer film 3 according to the position on the x-axis. A manufacturing method for forming a filter having such a refractive index will be described with reference to FIG.

FIG. 11 is a schematic view showing a vacuum chamber used for manufacturing this filter. In this drawing, a pair of high-refractive index and low-refractive index deposition materials 52 and 53 are arranged in a vacuum chamber 51 as first and second deposition sources. The high-refractive-index material uses, for example, TiO ₂ as described above, and the low-refractive-index material uses, for example, SiO ₂ . A parabolic rotating dome 54 having an open lower surface is provided at the upper part of the vacuum chamber 51, and is rotated at a constant speed in the direction of the arrow. Then, a substrate is attached to the center position of the inner surface via a substrate holder 55.

As shown in the sectional view of FIG. 12A, the substrate holder 55 is a holder for holding the substrate 56 and the electrode plate 57 in parallel with the substrate 56. The substrate 56 is a substantially square substrate substrate, and a square electrode plate is used as an electrode. For this electrode plate 57, an electrode pattern shape for changing the refractive index by changing the density of plasma formed around the substrate is selected. An optical monitor 58 for monitoring the film thickness is mounted on the upper portion of the substrate holder 55.

FIGS. 13A to 13D are views showing various examples of the electrode plates 57A to 57D used here.
In FIG. 3A, an electrode is formed by a square pattern having a low density near the center and a high density around the same point in the periphery. This pattern electrode is formed by plating a transparent substrate with gold or chrome. This electrode plate 5 shown in FIG.
7B is a square electrode centered on the same point with a high density at the center and a low density at the periphery. As shown in FIG. 13 (c), the electrode plate 57C has a low density on one side and a continuously high density on the other side as shown in FIG.
As shown in FIG. 13 (d), the electrode plate 57 whose density continuously increases in the left-right direction from the center portion may be used.
D can also be used.

The mounting angle of the substrate 56 is perpendicular to the axis of rotation of the center of the rotating dome. By rotating the rotating dome, the deposition materials 52, 53 having a high refractive index and a low refractive index are rotated.
Is controlled by rotation so that the average value is constant, a high-refractive-index film having a constant film thickness and a low-refractive-index film can be obtained. Then, a high-frequency voltage, for example, 1 KV, is applied between the vacuum chamber 51 and the electrode plate 57. At this time, the plasma formed around the substrate depends on the density of the electrodes. The higher the electrode density, the stronger the electric field and the higher the plasma density. Therefore, the O ₂ component varies depending on the plasma density. The higher the density of the O ₂ component, the higher the refractive index. Accordingly, the density of the low-refractive-index film and the high-refractive-index film formed on the substrate is accurately controlled according to the location by the plasma density. be able to.

The pattern of the electrodes is made to have a constant density.
As shown in (b), the electrode plate may be arranged at one end via a spacer 59 with a slight inclination with respect to the substrate 56. Also in this case, the density of the plasma formed around the substrate changes depending on the tilted angle, so that the refractive index can be continuously changed in a predetermined direction.

As shown in FIG. 14, an ion source 60 may be provided at the bottom of the vacuum chamber 51 to emit an ion gun toward the substrate, thereby generating plasma. By cutting out the substrate so that the refractive index continuously changes in a desired direction, the interference filter according to each of the embodiments described above can be manufactured.

[0037]

As described above in detail, the tunable interference light filter according to the first to fifth aspects of the present invention can linearly adjust the light irradiation position without rotating the tunable interference light filter. By changing the transmission wavelength, the transmission wavelength can be continuously changed. The transmission wavelength differs only depending on the incident position, and the transmittance does not change depending on the plane of polarization, and the same transmittance can be obtained for the P wave and the S wave. Further, an excellent effect is obtained that the full width at half maximum, which is the light selection characteristic, does not change depending on the irradiation position of the light and can be set to a constant value. In other words, the full width at half maximum does not depend on the polarization plane,
It is possible to continuously change only the wavelength while keeping the light transmittance and the light reflection position constant.

According to the sixth and seventh aspects of the present invention, it is possible to configure an optical filter device that continuously changes the selected wavelength by using the wavelength variable interference optical filter. According to the eighth and ninth aspects of the present invention, it is possible to easily form an interference light filter whose refractive index continuously changes in a predetermined direction.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating a configuration of a wavelength tunable interference light filter having a single cavity structure according to a first embodiment of the present invention, and FIG. 1B is a graph illustrating a change in transmittance on an x-axis thereof; It is.

FIG. 2 is a graph showing changes in a transmission wavelength, a full width at half maximum, and a transmittance with respect to an incident position in the present embodiment.

FIG. 3 is a graph showing wavelength selection characteristics with respect to the number of cavity layers.

FIG. 4 is a schematic diagram showing a use state of the wavelength variable interference light filter according to the present embodiment.

FIG. 5 is a perspective view showing a tunable interference light filter device using the tunable interference light filter according to the present embodiment.

FIG. 6 is a graph showing a spectrum change of incident light and outgoing light to the wavelength variable interference light filter device of the present embodiment.

FIG. 7A is a diagram illustrating a configuration of a wavelength variable interference light filter according to a second embodiment of the present invention, and FIG. 7B is a graph illustrating a change in transmittance thereof.

FIG. 8 is a graph showing changes in a transmission wavelength, a full width at half maximum, and a transmittance with respect to a rotation angle of a wavelength variable interference light filter according to a second embodiment of the present invention.

FIG. 9 is a schematic diagram showing a use state of a wavelength variable interference light filter according to a second embodiment of the present invention.

FIG. 10A is a front view showing a state in which two circular optical filters according to the second embodiment are bonded to each other, and FIG.
FIG. 4 is a front view showing a usage example in which four different tunable interference light filters are bonded to each other.

FIG. 11 is a schematic view showing a manufacturing process of the wavelength variable interference light filter according to the third embodiment of the present invention.

FIG. 12 is a sectional view showing a substrate holder, a substrate held by the substrate holder, and an electrode plate.

FIG. 13 is a view showing various electrode patterns of an electrode plate used in the present embodiment.

FIG. 14 is a schematic view showing a manufacturing process of the wavelength variable interference light filter according to the fourth embodiment of the present invention.

FIG. 15 is a schematic diagram illustrating a use state of the wavelength variable interference light filter.

[Explanation of symbols]

1, 1A, 1B, 41, 41A, 41B, 41C, 41
D Wavelength variable interference light filter 2,42 Substrate 3,43 Multilayer film 4,44 Antireflection film 11,14,23,29 Optical fiber 12,13 Lens 22,28 Collimate linker 24,26 Adjuster 25,27 Scale 31 Lower multilayer film 32 Cavity layer 33 Upper multilayer film 31L, 33L Low refractive index film 31H, 33H High refractive index film 51 Vacuum tank 52, 53 Deposition material 54 Rotating dome 55 Substrate holder 56 Substrate 57, 57A to 57D Electrode plate 58 Electrode monitor 59 Spacer 60 Ion source

Continuation of the front page (72) Inventor Yoshimi Ikeda 122, Kamimatsu, Komaki-shi, Aichi F-term in Santec OCC Co., Ltd. (reference) 2H041 AA21 AB10 AC01 AZ01 AZ05 AZ08 2H048 GA01 GA04 GA13 GA22 GA23 GA25 GA30 GA32 GA33 GA34 GA60

Claims (9)

[Claims] 1. A wavelength tunable interference light filter for continuously changing light transmitted in a predetermined wavelength range, comprising: a substrate formed of a material transmitting light in a range of wavelengths used; A first refractive index n ₁ ,
A first deposited material film having a thickness of d _{1 and} a second deposited material film having a second refractive index n ₂ having a refractive index lower than n ₁ and a thickness of d ₂ are alternately laminated to provide a multilayer deposited material film; The refractive indices n ₁ and n ₂ of the multi-layer deposited material film are configured to change continuously along a predetermined direction of the substrate. A wavelength variable interference light filter, wherein the wavelength of transmitted light is changed by changing the wavelength of the transmitted light along a predetermined direction of the substrate. 2. Assuming that the thickness of each layer of the multilayer deposited material film is d ₁ and d ₂ and the transmission wavelength at that position is λ, d ₁ = λ / 4n ₁ and d ₂ = λ / 4n ₂ , respectively. 2. The tunable interference light filter according to claim 1, wherein the refractive index of each film continuously changes. 3. The wavelength tunable type according to claim 2, wherein the vapor deposition material film is formed by inserting a cavity layer having a thickness d ₃ of λ / 2n ₁ between the multilayer films. Interference light filter. 4. The tunable interference light filter is formed on a rectangular plate-like substrate, and the refractive index of a deposition material film is continuously changed along a longitudinal direction thereof. The tunable interference light filter according to claim 1, wherein: 5. The tunable interference light filter according to claim 1, wherein said tunable interference light filter is formed on a disk-shaped substrate. 6. A wavelength tunable interference light filter according to claim 1, a first collimator for converting light from a light source into parallel light, and a first collimator facing the first collimator. A second collimator disposed to converge a light beam; and a second collimator disposed between the first and second collimators, the second variable collimator being arranged in a direction in which a refractive index of the variable wavelength interference light filter changes. And a moving means for moving the wavelength-variable interference light filter device. 7. A tunable interference light filter according to claim 1, a first collimator for converting light from a light source into parallel light, and a first collimator facing the first collimator. A second collimator arranged to converge a light beam; and a second collimator arranged between the first and second collimators, the wavelength-variable interference light being arranged in a direction in which a refractive index of the wavelength-variable interference light filter changes. A wavelength variable interference light filter device, comprising: a rotation unit for rotating the filter. 8. A first refractor, wherein a substrate is arranged on an inner surface of a rotating dome, which is provided in a vacuum chamber and has an open surface, perpendicularly to a rotation axis of the rotating dome, and an electrode is arranged on a back surface thereof. A first evaporation source having a refractive index and a second evaporation source having a second refractive index are arranged in the vacuum chamber, a voltage is applied between the electrode and the vacuum chamber, and the electric field is applied to the substrate. Changing the density of the plasma formed in the vicinity of the first and the second while rotating the rotating dome at a predetermined speed.
Characterized in that the evaporation sources are alternately evaporated, alternately evaporated until a predetermined film thickness is obtained, and laminated. 9. The tunable interference according to claim 8, wherein the electrode used for forming the plasma changes the density of the substrate radially from the center of rotation to the peripheral direction. Manufacturing method of optical filter.