JP2015225217A - Optical sheet for spectroscopy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a user-friendly optical sheet for spectroscopy capable of being manufactured with a simple structure and by a simple manufacturing method.SOLUTION: An optical sheet for spectroscopy includes a blazed diffraction grating at a light incident surface side and a flat surface at a light injection surface side. The blazed diffraction grating adjusts a prism angle, a refraction index, an adjacent prism gap, and the incident angle of incident light so as to guide one of diffraction light into the sheet and to inject the other at a rear surface flat surface side by a slight angular difference in the diffraction light generated by difference in a wavelength included in the incident light. The optical sheet for spectroscopy is molded by transferring the fine shape of the blazed diffraction grating at an extrusion molding time.

Description

The present invention relates to a spectroscopic element and the like, and more particularly to a spectroscopic element such as a transmission diffraction grating used in an optical apparatus.

In the use of light, there is a field of spectroscopy in which incident light is selected for each wavelength and utilized according to each purpose. For example, light-electrical conversion is used for ultraviolet light, illumination is used for visible light, and heat is used for infrared light. When performing spectroscopy, generally, a spectroscopic element such as a refractive optical element such as a prism or a diffractive optical element such as a hologram is used. In addition, in order to improve spectral efficiency, a precision processed spectral element such as a blazed diffraction grating can also be selected.

A spectroscopic element is an element that performs spectroscopic analysis utilizing differences in refractive index and diffraction efficiency for each wavelength. Light beams dispersed by wavelength by the spectroscopic element are emitted at different angles, and the amount of light can be measured for each angle. In the following, four typical methods for performing spectroscopy are described.

As a first method, there is a method using chromatic dispersion (chromatic aberration due to refraction) using a prism as a spectroscopic element. Since the amount of chromatic dispersion is determined by the material constituting the prism, it is common to use a glass material with increased chromatic dispersion.
However, in order to obtain sufficient color separation by the prism, there is a problem that the constraints on the layout become large, such as the need for incident light at a shallow angle.

As a second method, when a diffraction grating is used for spectroscopy, the angle of the light beam can be easily set by setting the diffraction grating pitch, and a large chromatic dispersion can be obtained. However, it is necessary to consider the influence of the accompanying higher-order diffracted light.

As a third method, there is a method in which only a light beam having a specific wavelength is strongly diffracted using a blazed diffraction grating in which the first and second methods are combined. That is, the prism angle is set so that the refracted light overlaps the diffracted light after the prism pitch is made as small as the diffraction grating. However, since it is necessary to use a resin suitable for precise shape transfer, such as a UV curable resin, in order to obtain a diffraction grating or a fine structure similar thereto, it is limited to processing of a thin film. In that case, a general plastic material cannot be used, and it becomes difficult to form a plate-like spectroscopic element.

As a fourth method, there is a method in which a specific wavelength is reflected or absorbed by using a colorant for spectroscopic purposes, but due to its characteristics, it is not suitable for use in selectively extracting light beams having a specific wavelength.

  For example, in Patent Document 1, a structure in which a plurality of diffraction gratings each having a grating surface on which a reflection film that reflects only light in a specific wavelength band is formed is stacked, and light in a specific wavelength band is reflected by the corresponding reflection film. A method of performing spectroscopic analysis is proposed.

  Further, in Patent Document 2, a structure in which a plurality of diffraction gratings having grating surfaces having blazed structures having different shapes corresponding to different specific wavelength bands is laminated, and light of a specific wavelength band is applied to each corresponding diffraction grating. A method of performing spectroscopy by refracting has been proposed.

However, the spectroscopic elements described in Patent Document 1 and Patent Document 2 have a problem that the diffraction grating needs to be multilayered as many as the number of wavelength bands to be subjected to spectroscopic analysis, and the element structure becomes complicated. In addition, since the emission position of the dispersed light beam is close, it is necessary to design the positional relationship between the stacked diffraction grating and the element that detects the light amount accurately, and the irradiation area and irradiation position are limited. There is.

One method for solving this is to adjust the emission positional relationship using a mirror or a lens. However, since the light utilization efficiency is lowered due to the loss at the time of catadioptric refraction at the interface, there is a drawback that the apparatus configuration becomes complicated, such as the need for a highly sensitive sensor at the time of measurement, and adjustment and maintenance are required.

JP 2011-90074 A JP 2012-208506 A

The present invention has been made in view of the above points, and enables continuous transfer of a diffraction grating shape to a plate-like sheet, and enables efficient spectroscopy, such as the position and area of a spectroscopic element. An object of the present invention is to provide an easy-to-use spectroscopic sheet that is not restricted.

n1 ： 入射側屈折率
n2 ： 出射側屈折率
θ1： 入射角
θ2： 出射角（透過）

α ： 入射角
β ： 出射角（反射）
ｄ ： 格子間隔
λ ： 波長
ｍ ： 整数 The invention described in claim 1
A spectroscopic element is formed on the light incident surface side of the sheet,
A spectroscopic optical sheet having a flat surface opposite to the light incident surface,
The spectroscopic optical sheet includes a surface layer on which the spectroscopic element is formed,
A back layer on which the flat surface is formed;
A laminate including at least a central layer provided between the surface layer and the back layer,
The spectroscopic element is shown by the following refracted light represented by the following formula 1 and formula 2 with respect to the shape of the spectroscopic element, the refractive index, the spacing between the adjacent spectroscopic elements, and the incident angle of light incident on the spectroscopic optical sheet. The spectroscopic optical sheet is characterized by satisfying a relationship in which the diffracted light beams coincide with each other.

n1: Incident side refractive index
n2: Output side refractive index θ1: Incident angle θ2: Output angle (transmission)

α: Incident angle β: Output angle (reflection)
d: Lattice spacing λ: Wavelength m: Integer

The invention described in claim 2
The MI (melt index) value of the material used for the surface layer and the back layer is higher than the MI value of the material used for the center layer,
The spectroscopic optical sheet according to claim 1.
The invention according to claim 3
The MI value of the material used for the surface layer and the back layer is in the range of 5.5 to 20, and the MI value of the center layer is in the range of 0.8 to 6,
The spectroscopic optical sheet according to claim 1.

The invention according to claim 4
The thickness ratio of the surface layer, the center layer, and the back layer is configured in the range of 2: 6: 2 to 0.3: 6: 0.3, respectively.
The spectroscopic optical sheet according to claim 1.
The invention described in claim 5
A measuring device, a display, or a photovoltaic power generation device comprising the spectroscopic optical sheet according to claim 1.

The spectroscopic sheet according to the present invention can select incident light in two directions of internal reflection that propagates through the spectroscopic sheet and external transmission that is refracted and emitted to the outside, and at the same time lowers the light utilization efficiency. Since strong diffracted light is generated without generating high-order diffracted light, it is possible to efficiently split the light beam.
Moreover, it becomes possible to improve the moldability, productivity, and shape restoration property of the surface shape.

It is the schematic which shows the spectrum by the spectrum sheet in this invention. It is the schematic when the spectroscopic sheet in the present invention has a three-layer configuration. It is a figure which shows the manufacturing method of the spectroscopic sheet in this invention.

An embodiment of the present invention will be described with reference to the drawings. For the sake of simplicity, the same reference numerals are assigned to corresponding parts in the drawings.

FIG. 1 shows an outline when a light beam 12 is incident on a spectral sheet 11 according to the present invention. FIG. 2 is a schematic sectional view showing an example of the layer structure of the spectroscopic sheet 11 in the present invention.

The spectroscopic sheet 11 of the present invention includes three layers having different mechanical strengths, that is, a center layer 21, a surface layer 22 that is a light incident surface, and a back layer 23 that constitutes the back side thereof.

The center layer 21 is desirably made of a material having a low MI value (melt index; fluidity index), that is, a hard material. Thereby, sufficient mechanical strength of the spectroscopic sheet itself can be obtained, and the entire spectroscopic sheet can be thinned.
Further, by using a resin having an MI value higher than that of the center layer 21 for the surface layer 22 or the back layer 23, a fine pattern having an edge can be transferred satisfactorily.

In addition, it is desirable that the surface layer 22 and the back layer 23 use the same material, but have the same thickness, that is, the layer ratio. Thereby, the deformation | transformation (warping) resulting from the heating at the time of spectroscopic sheet use can be suppressed. In other words, warping always occurs when an acrylic single-layer product is molded by an extrusion method, but the stress balance within the spectroscopic sheet can be maintained even when the temperature rises by making the spectroscopic sheet a multilayer structure. Deformation is suppressed and high temperature resistance can be improved.

  In the present embodiment, the spectroscopic sheet 11 has a three-layer configuration including the center layer 21, the surface layer 22, and the back layer 23. However, layers having other functions may be provided as appropriate.

The light beam 12 incident on the spectroscopic sheet 11 is split by the blazed diffraction grating 24 formed on the surface layer 22 and reaches the back layer 23 at an incident angle corresponding to the wavelength. Then, with the critical angle at which the total reflection occurs on the back surface as a boundary, the light beam 13 that is totally reflected toward the inside of the sheet and is guided through the sheet to be emitted, and the light beam 14 that is emitted to the outside of the sheet by transmission is split Can do.

Here, the shape of the blazed diffraction grating 24 provided on the surface layer 22 of the spectroscopic sheet is determined.
The angle of the light beam emitted from the spectroscopic sheet 11 is the angle of the light beam incident on the spectroscopic sheet 11, the refractive index of the resin composing the blazed grating, and the angle of the prism composing the blazed grating. ) Can be determined by defining.

n1 ： 入射側屈折率
n2 ： 出射側屈折率
θ1： 入射角
θ2： 出射角（透過）

α ： 入射角
β ： 出射角（反射）
ｄ ： 格子間隔
λ ： 波長
ｍ ： 整数

n1: Incident side refractive index
n2: Output side refractive index θ1: Incident angle θ2: Output angle (transmission)

α: Incident angle β: Output angle (reflection)
d: Lattice spacing λ: Wavelength m: Integer

Specifically, first, the angle of the prism is determined by applying Snell's law so that an arbitrary wavelength becomes the total reflection angle on the back surface side.
Thereafter, the prism pitch is determined by using the equations (1) and (2) so that the exit angle θ2 of the light beam emitted from the prism and the exit angle of the diffracted transmitted light by the repetitive structure of the prism match (so-called Littrow arrangement). ). Thus, a blazed diffraction grating 24 that generates strong first-order diffracted light can be obtained. In addition, the outgoing angle of the transmitted light by diffraction is an angle that is obtained as a surface object on the surface of the spectroscopic sheet by obtaining the outgoing angle β of reflection.
Since the refractive index is determined by the material of the surface layer, it is appropriately selected.

When manufacturing the spectroscopic sheet 11, a multilayer extrusion method using a T-die, an injection method, an extrusion coating method, or the like can be used. In the spectral sheet 11 obtained by the present invention, since a hard resin layer is selected as the center layer 21, it is possible to manufacture by the extrusion method, which has conventionally been difficult to transfer with high accuracy, and the productivity is higher than that of the injection method. Can be improved.
Below, the case where the multilayer extrusion method by T die excellent in productivity is used is demonstrated using FIG.

The multi-layer extrusion method using T-die is to connect an extruder that melts and discharges different types of resin to the feed block, merges and multi-layers in the feed block, and then discharges as a multilayer resin film while cooling the resin with a cooling roll. It is a method to make it.

The resin 36 constituting the center layer 21 and the resin 37 constituting the surface layer 22 and the back layer 23 are melted by different extruders 31 a, b and c and supplied to the T die 32. In addition, about the lamination | stacking method of each resin, the general multilayering technique currently utilized can be used. That is, it may be performed by a feed block (not shown) or the like provided in the upstream portion of the T die 32, or may be multi-layered inside the T die 32.

The molten resin that has reached the take-up machine (not shown) is sandwiched between the cooling roll 33 and the cooling roll 34. At that time, the roll temperature, torque, and pinching pressure are adjusted so as to be in close contact with the cooling roll 34.
At this time, it is possible to adjust the thickness by controlling the force sandwiched between the cooling rolls, but it is necessary that the resin be kept at a temperature that can be deformed by an external force.

Heat removal is performed by the cooling roll 34 and the cooling roll 35, and sheeting is performed while adjusting the temperature difference and tension of the cooling roll to correct the warp of the sheet.

It is important to prevent the occurrence of flow marks when performing the multilayer extrusion method. A flow mark is a phenomenon that occurs because, when resins having high fluidity are combined, each has a different fluidity from the other. As a general measure, a method is adopted in which a resin having a MI value close to that of each layer of resin is selected and the flow speed after discharging the T-die is made uniform.

On the other hand, in the present invention, as described above, since the intermediate layer 21, the surface layer 22, and the back layer 23 use resins having different MI values, the temperature of the resin layered in the T-die is adjusted for each layer, It is necessary to determine a discharge condition that does not generate a flow mark.
That is, by selecting a resin having a high viscosity for the center layer 21 and adjusting the discharge conditions (temperature and discharge amount) so that a low-viscosity resin such as the front layer 22 or the back layer 23 is thinly aligned, the flow mark is excellent. Can be obtained.

At this time, the rotational speed of the extruder 31, the lip bolt of the T die, the temperature condition, and the like are also adjusted so that the resin sheet has an appropriate layer ratio and thickness.

When the resin sheet thus obtained is thin, a slitter is selected, and when it is thick, a circular saw, a running saw, laser cutting, or the like is appropriately selected and cut to obtain the spectral sheet 11 of the present invention.

Next, a method for transferring the shape of the blazed diffraction grating 24 to the surface layer 22 will be described.
As an example of a transfer method in the case where an optical shape is provided on the surface layer 22 of the spectroscopic sheet 11, the optical shape is engraved in advance on a base material such as resin or metal constituting the cooling roll, and the shape is transferred.

The cooling roll that performs shape transfer performs copper plating on the iron core and engraves the copper plating layer. For example, it is formed by using a cutting tool using a diamond tool, a grinding process using a grindstone, an etching process that selectively corrodes, and many other existing patterning techniques.
By performing chromium plating on the copper plating layer, it becomes possible to protect the copper plating layer by improving the surface hardness.

In addition to this, a highly durable roll in which metal or ceramic is thermally sprayed and polished on the cylinder surface, a roll having a shape cut on the nickel surface, or the like may be used.
The resin sheet sufficiently cooled by the cooling roll can be manufactured by a winding process if it is a film, or by a cutting process if it is a plate.

In the manufacturing process described above, since the shape transfer to the resin sheet is performed with the surface layer 22 in a molten state, it is desirable that the resin temperature be high and that the upstream side be as close to the T die 32 as possible. For example, in the case of an acrylic resin, transferability is improved when heated to 245 ° C., and a spectral sheet having an effective width of 500 mm and a thickness of 2 mm can be obtained by discharging at a discharge rate of about 100 kg / h.

As another shape transfer method, after forming a transparent multilayer resin sheet, shape forming may be performed by post-processing such as cutting or hot pressing.

The spectroscopic sheet 11 in the present invention is made of a transparent member, and can be configured using a general optical transparent resin. If a plastic material that is relatively easy to process, for example, polycarbonate resin, MS (methacrylstyrene) resin, or the like, is used, it is possible to have a feature that is excellent in impact resistance and is difficult to break. Further, if acrylic resin or polystyrene resin is used, it is possible to improve the abrasion resistance.

The central layer 21 of the spectral sheet 11 of the present invention desirably has high transparency while having the mechanical strength of the spectral sheet 11 itself. In general, the aforementioned polycarbonate or acrylic resin is preferably selected.
In addition, the surface layer 22 or the back layer 23 of the spectroscopic sheet 11 may be made of a material having an MI value different from that of the resin constituting the center layer 21. For this reason, for example, a combination of different resins such as the above-mentioned polycarbonate and acrylic may be used.

When different resins are combined, they can be manufactured relatively easily, but if there is a difference in processing conditions depending on the melting temperature of the resin and the viscosity at the time of melting, the workability may be significantly reduced.
In this case, the same type of resin with different molecular weights or those with additives added can be selected to easily satisfy the processing conditions such as the melting temperature and viscosity at the time of melting. Becomes easy.

When selecting the resin constituting the three layers, as described above, the mechanical strength of the center layer 21 and the shape transferability to the surface layer 22 or the back layer 23 are the most important.
Since the mechanical strength of the spectroscopic sheet 11 is substantially determined by the MI value of the center layer 21, a resin having a relatively low MI value is selected. For example, when a resin having an MI value of 0.8 to 6 (for example, VH4, VH5, MD, etc., is an acrylic resin manufactured by Mitsubishi Rayon, etc.), it is a good machine in the range of the layer ratio described below. Strength can be obtained.

When the shape is transferred to the surface layer 22 or the back layer 23, the MI value is in the range of 5.5 to 20 (for example, VH5, TF8, TF9, etc. in the case of Mitsubishi Rayon acrylic resin). preferable. Within this range, it is easy to balance the line speed (time for pressing the mold) and the pressure applied to the resin, and it is possible to transfer the shape of a pattern having an edge like a prism shape. Furthermore, since the surface layer becomes relatively soft and the shape restoration property of the material is improved, it is possible to obtain an effect that durability and durability are less likely to occur, such as rusting and cracking.

More preferably, if the MI value of the surface layer 22 or the back layer 23 is in the range of 10 to 20 and the MI value of the center layer 21 is in the range of 2 to 6, sufficient effects can be obtained and the productivity is also good. It becomes.

When the MI value of the surface layer 22 or the back layer 23 is less than 5.5, the shape transferability is poor. Further, when it exceeds 20, it becomes difficult to select a material having a MI value of the center layer 21 or less.
If the MI value of the center layer 21 is less than 0.8, the resin viscosity is too high and smooth sheeting becomes difficult, and the fluidity is not compatible with the surface layer 22 or the back layer 23 and a flow mark is also generated. Therefore, the appearance is poor. This flow mark is not desirable because it also occurs when the MI value of the central layer 21 exceeds 6.

In order to obtain the effect of total reflection and reflection of incident light at the boundary surface in the spectroscopic sheet, the difference in refractive index between the front and back layers and the intermediate layer may be less than 0.05, and particularly less than 0.001. Then, the light action at the boundary surface can be ignored. When selecting the same type of resin, the difference in refractive index due to grades and additives is very small and has almost no effect, so a wide variety of resins can be selected.
For example, when an acrylic resin is selected, in the case of Mitsubishi Rayon Acrypet VH and TF9, both have a refractive index of 1.490, and a combination having a refractive index difference of less than 0.0001 is obtained.

In addition, by forming the thickness ratio in the center of each layer in the range of 2: 6: 2 to 0.3: 6: 0.3, for example, a single layer manufactured only with the resin used for the center layer of this configuration It can have the same sheet characteristics as the product.
When the surface layer is thickened exceeding 2: 6: 2, the discharged resin is too soft, resulting in a bank mark, making sheeting difficult. Further, when the surface layer is made thinner than 0.3: 6: 0.3, it is difficult to maintain a uniform thickness distribution of the resin layer, and it is not desirable because it causes problems such as partial transfer of the shape.

The present invention can be applied as a spectroscopic element, and in particular, a large and plate-like spectroscopic sheet can be obtained. Therefore, the present invention can be applied not only for measurement but also in fields such as a display and sunlight utilization. As an example of the use of sunlight using the optical sheet for spectroscopy of the present invention, an arbitrary wavelength in sunlight can be dispersed with the spectrum sheet, and the photovoltaic power generation apparatus can be efficiently irradiated. For example, by splitting sunlight into infrared light and visible light, it is possible to use a solar power generation device optimally designed for power generation with visible light and power generation using the thermoelectric effect with infrared light. Operation becomes possible.
In another case, solar power generation includes a method in which visible light with relatively low utilization efficiency is dispersed and used for plant growth instead of power generation. This is because in the normal spectroscopic method, the emission position of the dispersed light beam is the same point or very close position, making it difficult to install both spatially. However, in the spectroscopic sheet of the present invention, the light emission position after the separation is separated. -Since it can be adjusted, a plant can be efficiently grown simultaneously with the use of the solar power generation device. In addition, since the light used for the plant growth use in this example does not contain infrared light, the efficiency of photosynthesis is also increased, and a plant growth promoting effect can be expected.

  As mentioned above, although embodiment of this invention was illustrated, this invention is not limited to the said embodiment, It cannot be overemphasized that a design change etc. can be performed unless it deviates from the technical idea of this embodiment.

Example 1
An experiment was conducted to transfer a prism shape having an apex angle of 90 ° to the surface layer of a molded product having a width of 500 mm, a sheet thickness of 2 mm, and a thickness ratio of 0.5: 6: 0.5 at the center of each layer by multilayer extrusion. .

Note that TF9 (MI value: 20) manufactured by Mitsubishi Rayon was selected as the material for the front and back layers forming the blazed diffraction grating 24. As the intermediate layer 21, VH made by Mitsubishi Rayon, which has stable physical properties and is easy to perform sheeting, was selected.

(Example 2)
An experiment was conducted to measure the amount of warpage of this component. The spectroscopic sheet obtained in Example 1 was cut into 774 mm × 430 mm and left at 80 ° C. for 2 hours.

(Example 3)
With the same layer structure (resin type, layer ratio) as in Example 1, the take-up speed of the extruder was increased, the spectral sheet was manufactured with a thickness of 1 mm, and the strength was confirmed.

Example 4
An experiment was conducted in which light was incident on the spectroscopic sheet 11 of the present invention having the same layer configuration (resin type, layer ratio) as in Example 1, and ultraviolet rays and other wavelengths were dispersed.
Refractive index for each wavelength of TF9 made by Mitsubishi Rayon selected as the surface layer is 1.4891 for C line (λ = 656 nm), 1.4915 for D line (λ = 587 nm), and 1 for F line (λ = 486 nm). 4875, g-line (λ = 436 nm) is 1.5027. That is, in this embodiment, the problem is to split g-rays that become ultraviolet light and other light rays.

First, each value regarding the shape of the blazed diffraction grating 24 was determined from the equations (1) and (2). That is, the incident-side prism angle was set to 83 °, the incident angle of the light beam 12 was set to 6 ° with respect to the sheet normal, and the prism pitch was set to 0.40 μm.
Next, the determined blazed diffraction grating shape was engraved on the mold of the cooling roll 34. A three roll type take-up machine was used for cooling the resin.

(Comparative Example 1)
As a comparative example of Example 1, a single-layer product manufactured using only the center layer 21 (VH manufactured by Mitsubishi Rayon) was prepared, and a prism-shaped transfer experiment having a 90 ° apex angle was performed.

(Comparative Example 2)
A single-layer product similar to Comparative Example 1 was prepared, and an experiment similar to Example 2 was performed.

(Comparative Example 3)
A single-layer product similar to Comparative Example 1 was prepared, and an experiment similar to Example 3 was performed.

(Experimental result)
In this component of Example 1, the resin reached 100% of the prism shape having a 90 ° apex angle, and complete shape transfer could be realized. On the other hand, in the single-layer product of Comparative Example 1, the resin reached only about 60% of the prism shape, resulting in incomplete shape transfer. This is because the viscosity of the melted surface layer 22 is lower than that of the single-layer product obtained in Comparative Example 1 for this component.

In this configuration product of Example 2, the warpage amount was 3 mm in the longitudinal direction. On the other hand, in the single layer product of Comparative Example 2, the warpage amount was 17 mm. The allowable range of warpage varies depending on the intended use, but is generally within 3 mm. From the results of Example 2 and Comparative Example 2, it is considered that this component is sufficiently practical, while the single-layer product is limited in usable applications.

With this component of Example 3, a spectroscopic sheet having excellent productivity could be obtained without causing cracks or chipping when lifted manually. On the other hand, the single-layer product of Comparative Example 3 was cracked and chipped when lifted manually, resulting in significant loss of productivity.

  From the above experimental results, it can be confirmed that the spectral sheet obtained by the present invention can transfer the prism shape in accordance with the optical design well and has the necessary strength.

In the result of Example 4, on the flat surface on the back layer side, it was confirmed that light rays other than g-line were refracted and emitted from the sheet, and only g-line was totally reflected and not emitted from the sheet but guided inside the sheet. did it. Further, it was confirmed that high-order diffracted light was not generated and the maximum diffraction efficiency was obtained, and the transmitted diffracted light and the refracted light were superposed to perform efficient spectroscopy.

DESCRIPTION OF SYMBOLS 11 ... Spectral sheet 12 ... Incident light 13 ... Light beam 14 guided and emitted 14 ... Light beam 21 emitted by transmission 21 ... Main layer 22 of the spectral sheet of the present invention ... Surface layer 23 of the spectroscopic sheet of the present invention ... Back layer 24 of the spectroscopic sheet of the present invention ... Blaze diffraction grating 31a ... Extruder 31b ... Extruder 31c ... Extruder 32 ... T-die 33 ..Cooling roll 34 ... Cooling roll 35 ... Cooling roll 36 ... Resin 37 constituting the main layer ... Resin 38a constituting the surface layer or back layer ... Resin pellet 38b ... Resin pellet 38c ... resin pellet 39 ... screw

Claims (6)

A spectroscopic element is formed on the light incident surface side of the sheet,
A spectroscopic optical sheet having a flat surface opposite to the light incident surface,
The spectroscopic optical sheet includes a surface layer on which the spectroscopic element is formed,
A back layer on which the flat surface is formed;
A laminate including at least a central layer provided between the surface layer and the back layer,
The spectroscopic element satisfies the relationship of the following formulas 1 and 2 with respect to the shape of the spectroscopic element, the refractive index, the spacing between the adjacent spectroscopic elements, and the incident angle of light incident on the spectroscopic optical sheet. Spectral optical sheet.

n1: Incident side refractive index
n2: Output side refractive index θ1: Incident angle θ2: Output angle (transmission)

α: Incident angle β: Output angle (reflection)
d: Lattice spacing λ: Wavelength m: Integer The surface layer, the back layer, and the center layer are composed of layers having different mechanical strengths,
The spectroscopic optical sheet according to claim 1. The MI (melt index) value of the material used for the surface layer and the back layer is higher than the MI value of the material used for the center layer,
The spectroscopic optical sheet according to claim 1 or 2. The MI value of the material used for the surface layer and the back layer is in the range of 5.5 to 20, and the MI value of the center layer is in the range of 0.8 to 6,
The spectroscopic optical sheet according to any one of claims 1 to 3. The thickness ratio of the surface layer, the center layer, and the back layer is configured in the range of 2: 6: 2 to 0.3: 6: 0.3, respectively.
The spectroscopic optical sheet according to any one of claims 1 to 4.   A measuring device, a display, or a solar power generation device comprising the spectroscopic optical sheet according to claim 1.

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