JP4376507B2 - Polarizing optical element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a polarizing optical element.
[0002]
[Prior art]
A polarizing element is an optical element that transmits light linearly polarized in a specific direction, and is widely used in various optical devices. A widely known polarizing element is tourmaline, but it is expensive and unsuitable for incorporation as a component in an optical device. As a polarizing element that has good mass productivity and can be manufactured at low cost, a “wire grid type polarizing element” in which a one-dimensional line grating is formed on a transparent substrate with thin wires made of a conductive material has been proposed (see Patent Documents 1 to 3). ).
[0003]
The wire grid type polarizing element utilizes the fact that “the electric body is free of electric field”. That is, when natural polarized light is incident on such a polarizing element, the vibration component in the longitudinal direction of the lattice line in the one-dimensional line grating of the oscillating electric field becomes 0 in the lattice line. Transmits linearly polarized light that oscillates in the direction.
[0004]
Since the one-dimensional line grating is formed on the substrate surface, the ones described in Patent Documents 1 and 2 are easy to peel off from the substrate, and there are strong restrictions on the use mode. The one described in Patent Document 3 has a configuration in which a one-dimensional line lattice is sandwiched between a pair of substrates, and the substrate functions as a protective material for the one-dimensional line lattice. However, it is not always easy to manufacture because of the “structure in which the dimensional optical grating is sandwiched between a pair of substrates”.
[0005]
Patent Document 1 also describes a grid-type polarizing element using an organic resin material as a transparent substrate, but those using an organic resin material have low heat resistance and mechanical strength, and there are strong restrictions on use modes. .
[0006]
[Patent Document 1]
JP-A-10-153706
[Patent Document 2]
US Pat. No. 6,122,103
[Patent Document 3]
US Pat. No. 6,288,840 B1
[0007]
[Problems to be solved by the invention]
  It is an object of the present invention to realize a polarizing optical element using a novel inorganic polarizing element which is a wire grid type polarizing element and has a simple structure and excellent heat resistance and mechanical strength.
[0008]
[Means for Solving the Problems]
  Of this inventionPolarization opticsThe element is “a flat surface of a transparent substrate made of an inorganic material is embedded with a one-dimensional line grating made of a conductive material, and the exposed portion of the embedded one-dimensional line grating and the flat surface of the substrate are the same plane.1-dimensionalLine grid structureOne end of the featureAnd
[0009]
FIG. 1 shows a basic configuration as an explanatory diagram.
Reference numeral 1 denotes a “transparent substrate made of an inorganic material”. A “one-dimensional line grid made of a conductive material” is embedded on the flat surface 1 </ b> A side of the substrate 1.
Code 2_i-12_i2_{i + 1}2_{i + 2},... Show a cross section of each “grid line” with a conductive material embedded as a one-dimensional line grid.
[0010]
The lattice lines 2i and the like extend long in a direction orthogonal to the drawing, and are arranged in a one-dimensional lattice shape in the left-right direction of the drawing to constitute a “one-dimensional line lattice”. Further, the exposed portion of each lattice line in the embedded state and the flat surface 1A of the base body 1 form the same plane.
[0011]
The one-dimensional line grating is “embedded in a flat surface of a transparent substrate made of an inorganic material” is a so-called structural feature of the inorganic polarizing element, and is formed in advance in the manufacturing process of the inorganic polarizing element. The one-dimensional line grating is not “mechanically embedded in the substrate surface”.
[0012]
  Claim 1Polarizing optical elementHas the following characteristics in the above structure.
  That is, the refractive index: n of the transparent substrate 1 made of an inorganic material, the arrangement pitch of each lattice line 2i of the one-dimensional line lattice made of a conductive material: d, and the wavelength of light: λ are:
  (1) 0 <n · d / λ <0.7
Satisfied.
[0013]
  That is, generally, the condition (1) may be satisfied by reducing the product of the refractive index: n and the pitch: d as the wavelength of the light to be polarized becomes shorter.
  Other features of the polarizing optical element according to claim 1 will be described later.
[0014]
As will be described later, the cross-sectional shape of each grid line of the one-dimensional line grid can be various shapes other than the “rectangular shape” shown in FIG. 1, but the “rectangular shape” is crossed as shown in FIG. In the case of a surface shape, the value of the above parameter: n · d / λ is set to 0.1, and the width of the “rectangular shape”: a, thickness: t, refractive index: n, arrangement pitch: d, wavelength: λ But the condition:
(2) 0 <a <d
(3) 0 <t <0.22λ / n
Is preferably satisfied (claim 2).
[0015]
  The polarization opticsIn the element, the cross-sectional shape of each lattice line in the one-dimensional line lattice made of a conductive material can be “trapezoidal shape, wedge shape, semicircular shape, or semielliptical shape” in addition to the above rectangular shape. Item 3).
[0016]
  In each case aboveThe conductive material constituting the one-dimensional line grid can be “metal” (claim 4). As the conductive material, a semiconductor material can be used in addition to the metal. The metal may be any of aluminum, silver, gold, or chromium (Claim 5).
[0017]
  Polarizing optical elementIs used as a polarizing element that reflects non-transmitted light with respect to visible lightIsPreferably, the one-dimensional line grating is formed of “aluminum or silver” having a high reflectivity with respect to visible light (Claim 6). Conversely, “polarized light that does not reflect non-transmitted light with respect to light in the visible range. When used as an “element”, it is preferably formed of “chromium” that easily absorbs visible light.Also "Near RedWhen used as a “polarizing element that reflects non-transmitted light with respect to light in the outer region”, the one-dimensional line grating is preferably formed of “gold”.
[0018]
  In addition, it is also conceivable to implement as a polarizing plate by “a substrate made of an inorganic material is a parallel plate”..
  The polarizing optical element of the present invention has “the polarization function and other optical functions”Optical elementIt is.
  That is,A refracting surface is formed on the “part where the one-dimensional line grating is not formed” of the substrate made of an inorganic material, and the “optical action in cooperation with the one-dimensional line grating” is provided.
[0019]
For example, a substrate made of an inorganic material is formed as a “right angle prism”, and one of the two surfaces other than the inclined surface is embedded with a one-dimensional line grating to form a polarizing element surface, and the other surface is a lens surface (refractive surface). And a reflective surface is formed on the slope. In this way, for example, spontaneously polarized light is incident from the polarizing element surface, linearly polarized light is reflected by the reflecting surface, and the reflected light is diverged or focused by the action of the lens surface. it can.
[0020]
  Claim 1The polarizing optical element “a lens surface is formed on the surface of the substrate made of an inorganic material opposite to the surface on which the one-dimensional line grating is formed”, and further, “one side is formed on a flat surface in which the one-dimensional line grating is embedded. Integrating a lens with a flat surfaceHas been. That is, the polarizing optical element according to claim 1Then, a one-dimensional line grating made of a conductive material is “a form sandwiched between two lens surfaces”.
[0021]
  As a similar polarizing optical element“A structure in which a microlens array is formed on the surface of the substrate made of an inorganic material on the side opposite to the surface on which the one-dimensional line grating is formed”.Can be considered.
[0022]
  As another similar example, there can be considered a liquid crystal element “in combination with a liquid crystal element capable of electrically controlling the polarization direction of transmitted light, combining the inorganic polarizing element according to claim 9 as a pair, a polarizer and an analyzer”. , Using this "liquid crystal switching element"Can be realized.Further, when the liquid crystal elements are arranged in an array, it can be configured as a liquid crystal panel.
[0023]
  further“For liquid crystal element arrays that can electrically control the polarization direction of transmitted light for each element,Similar to aboveA pair of polarizing optical elements is combined as a polarizer and an analyzer, and the array arrangement of the microlenses in the polarizing optical element is matched with the array arrangement of the liquid crystal element array. The light utilization efficiency in the liquid crystal panel can be increased by condensing light on the liquid crystal elements of the liquid crystal element array by each microlens of the microlens array.
[0024]
In addition, although the inorganic material which comprises the base | substrate with which the one-dimensional line grating | lattice by an electroconductive material is embedded can use quartz glass and various usual optical glass suitably, it is not restricted to this and with respect to a use wavelength with inorganic material. Can be used as appropriate.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments will be described.
  Figure 2FIG. 4 is a diagram for explaining the optical action of the inorganic polarizing element using the one-dimensional line grating and the one-dimensional line grating. The optical action and the form of the one-dimensional line grating will be explained using this figure..
  As shown in FIG. 2A, the inorganic polarizing element 10 has a “parallel plate shape”, and a one-dimensional line grating 10B made of a conductive material is embedded on one side of a parallel plate-like substrate 10A made of an inorganic material. Is formed. Optical glass is assumed as the substrate 10A, and metal is assumed as the conductive material of the one-dimensional line grating 10B.
[0026]
As shown in FIG. 2A, when the incident light LI is incident from one side of the inorganic polarizing element 10, an electric field vibration surface is provided in the longitudinal direction (vertical direction in the figure) of the lattice line in the one-dimensional line lattice 10B. A component (hereinafter referred to as “vertically polarized light”) is reflected as reflected light LR, and a component having an electric field vibration plane in the lattice arrangement direction of the one-dimensional line grating 10B (hereinafter referred to as “horizontal polarized light”) is transmitted light LT. It becomes transparent. In this way, light in a linearly polarized state can be obtained as transmitted light LT and reflected light LR.
[0027]
FIG. 2B shows a partial cross section of FIG. 10B_i-110B_i10B_{i + 1},... Indicate “grid lines made of a conductive material” constituting the one-dimensional line grid 10B, and each grid line 10B_iAre linearly extended in a direction orthogonal to the drawing of FIG. 2B and arranged in parallel in the left-right direction of the drawing to form a “one-dimensional line lattice”.
[0028]
The exposed portion (upper surface in the figure) of the embedded one-dimensional line grating 10B and the flat surface of the base 10A form the same plane. In this embodiment, both surfaces of the substrate 10 are coated with “antireflection films”.
[0029]
Each grid line 10B_iThe cross sectional shape is a rectangular shape having a width: a and a thickness: t. As shown in the figure, a lattice line 10B in a one-dimensional line lattice._iAnd the relationship between width: a and pitch: d is a = d / π (π is the circumference). Further, the refractive index of the inorganic material constituting the substrate 10A is “n”, and the wavelength of the incident light LI is “λ”.
[0030]
At this time, n · d / λ is changed as a dimensionless parameter, and the change in transmittance with respect to each polarized light when the vertically polarized light and the horizontally polarized light are incident on the inorganic polarizing element 10 is examined by “electromagnetic field analysis”. As a result, it became as shown in FIG.
The vertical axis in FIG. 3 is the transmittance, and the horizontal axis (logarithmic scale) is the parameter: n · d / λ.
[0031]
As is clear from this figure, when the parameter: n · d / λ is 0.1 or less, the horizontally polarized light is almost completely blocked and the vertically polarized light is almost completely transmitted. Further, when the parameter: n · d / λ is 0.7 or less, the transmittance of horizontally polarized light is 20%, and the transmittance of vertically polarized light is 80%.
[0032]
Therefore, the range of parameters: n · d / λ in which the inorganic polarizing element 10 can be practically used as a “polarizing element” is as follows:
(1) 0 <n · d / λ <0.7
It turns out that it is the range of. In particular, when the parameter: n · d / λ is 0.1 or less, a good extinction ratio can be realized and the deflection element is extremely good.
[0033]
  That is, the inorganic polarizing element 10 shown in FIG. 2 has a one-dimensional line grating 10B made of a conductive material embedded in a flat surface of a transparent base 10A made of an inorganic material, and an exposed portion of the embedded one-dimensional line grating 10B. The flat surface of the substrate 10A is formed so as to form the same plane, the refractive index of a transparent substrate made of an inorganic material: n, the arrangement pitch of each lattice line of a one-dimensional line grating made of a conductive material: d, the wavelength of light : Λ satisfies condition (1)Satisfied.
[0034]
Next, in the embodiment of FIG. 2, the parameter is set to n · d / λ = 0.1 (that is, d = 0.1λ / n), and under this condition, the width of the lattice line: a and the arrangement pitch: Ratio of d: FIG. 4 shows changes in the transmittance of horizontal and vertical polarized light when a / d is changed. The change in extinction ratio (transmission of horizontal polarized light / transmittance of vertical polarized light) at this time is shown in FIG. As shown in FIG. The vertical axis in FIG. 5 represents the extinction ratio.
[0035]
As apparent from FIG. 4, when a / d increases, the transmittance of vertically polarized light decreases rapidly, whereas the transmittance of horizontally polarized light reaches approximately 100% until a / d = 0.2. It has a rate, and after that, it tends to decrease gradually. On the other hand, as shown in FIG. 5, the extinction ratio gradually increases as a / d increases as shown in the figure, and has a maximum when a / d is about 0.7.
[0036]
That is, the grid line width: a is related to the pitch: d,
(1) 0 <a <d
However, since the transmittance of vertically polarized light increases as a approaches 0, the “polarization efficiency” for linearly polarizing incident light becomes worse. Further, as a increases, the transmittance of horizontal polarization decreases rapidly, but as a approaches d, the transmittance of horizontal polarization gradually decreases. This is because the distance between the lattice lines is reduced and the transparent region is narrowed. For this reason, when a approaches d, the polarization efficiency increases, but the polarizing element becomes “dark”.
[0037]
On the other hand, the extinction ratio increases abruptly as a approaches d. Considering this point, the more preferable range of a / d is from the viewpoint of polarization efficiency and brightness.
0.1 <a / d <0.8
Furthermore, considering the extinction ratio as well as the polarization efficiency and brightness,
0.2 <a / d <0.8
Is a more preferable range.
[0038]
Next, under the condition of n · d / λ = 0.1, the lattice line 10B_iFIG. 6 shows the change in transmittance of horizontal and vertical polarized light when the ratio of width: a and thickness: t in t: t / a is changed, and FIG. 7 shows the change in extinction ratio. The vertical axis in FIG. 7 is the extinction ratio.
[0039]
As is clear from FIG. 6, the transmittance of vertically polarized light hardly depends on t / a, but the transmittance of horizontally polarized light tends to gradually decrease as t / a increases. Further, as is apparent from FIG. 7, it can be seen that the extinction ratio increases and saturates as t / a increases.
[0040]
As shown in FIG. 7, since the extinction ratio (vertical axis) is “saturated when t / a is approximately 7 or more”, the extinction ratio cannot be changed even if the thickness t is greater than 7a.
Therefore, the range of “thickness where a desired value can be set as the extinction ratio: t” is considered to be t <7a.
[0041]
The conditions for obtaining the extinction ratio characteristic of FIG. 7 are n · d / λ = 0.1 and a = d / π since d = πa, n · d / λ = n ·, as described above. Since πa / λ = 0.1, a = 0.1λ / (π · n), from which the range “t <7a” is
t <7 · 0.1λ / (π · n) = (0.7 / 3.14) λ / n = 0.22λ / n
And eventually the condition:
(3) 0 <t <0.22λ / n
Is satisfied, the extinction ratio is 1:10 to 1:10.⁸It is possible to set to a “desired value” within the range. (Claim 2).
[0042]
On the contrary, when t ≧ 7a, the extinction ratio is saturated, and there is no change in the extinction ratio in this region. Therefore, in this region, “the transmittance of the horizontally polarized light is appropriately adjusted with respect to the saturated extinction ratio. It is possible.
[0043]
In the above, the “cross-sectional shape of each lattice line constituting the one-dimensional line lattice” in the inorganic polarizing element is a rectangular shape, but various other cross-sectional shapes of the lattice line are possible.
[0044]
In the example shown in FIG._iThe cross-sectional shape such as “inverted trapezoidal shape” is the lattice line 22 in the example shown in FIG._iThe cross-sectional shape such as “wedge shape” is the lattice line 23 in the example shown in FIG._iThe cross-sectional shape such as “a semi-elliptical shape” is defined in claim 3.
[0045]
Of course, the above condition (1) is also effective in the case of a one-dimensional line grating having various cross-sectional shapes as shown in FIG. In the case of the various cross-sectional shapes described above, a range of “thickness that can set a desired value as the extinction ratio: t” corresponding to the condition (3) can be set. In this case, the thickness: t is obtained by multiplying the “groove depth” in each cross-sectional shape shown in FIG. 3 by a coefficient (according to the cross-sectional shape).
In addition to the above, various shapes such as a “semicircular shape” are allowed for the cross-sectional shape of the grid lines.
[0046]
Here, in the inorganic polarizing element of the present invention, the one-dimensional line grating made of the conductive material is embedded in the flat surface of the transparent substrate made of the inorganic material, and the exposed portion of the embedded one-dimensional line grating and the flat surface of the substrate are embedded. A method for realizing the structure in which the surfaces are the same plane will be briefly described. Various methods for realizing such a structure are possible.
[0047]
For example, assuming optical glass as an inorganic material, a photoresist layer is formed on a flat surface of the optical glass, and a pattern corresponding to a one-dimensional line lattice is formed on the photoresist layer by electron beam drawing or X-ray drawing. "Is written, and development is performed to remove the" photoresist of the portion to be a lattice line ".
[0048]
Next, etching is performed using the developed photoresist layer as a mask, and the “pattern corresponding to the one-dimensional line grating” formed on the photoresist is transferred to the flat surface of the optical glass, and “one-dimensional” is applied to the optical glass surface. A groove pattern corresponding to the line grating ”is formed.
[0049]
In this state, a metal material, for example, aluminum is deposited on the surface of the photoresist layer and “one-dimensional line lattice” by a chemical vapor deposition method such as CVD (chemical vapor deposit), a film formation method using physical vapor deposition, or a deposition method such as plating. It is attached in a layered manner to the “corresponding groove pattern”.
[0050]
After that, when the “aluminum-attached photoresist layer” is removed from the flat surface of the optical glass, an array of fine aluminum wires corresponding to a one-dimensional line lattice is obtained. The “aluminum portion raised from the optical glass surface” is removed, and the embedded “exposed portion of the one-dimensional line grating made of aluminum” and the flat surface of the substrate form the same plane.
[0051]
As another method, a “groove pattern corresponding to a one-dimensional line lattice” is directly processed on the flat surface of the optical glass by electron beam drawing or the like, and the entire flat surface is formed by chemical vapor deposition such as physical vapor deposition or CVD. Aluminum is deposited and the groove pattern is filled with aluminum. Thereafter, by removing “aluminum on the flat surface” by electron sputtering or the like and leaving only the aluminum filled in the grooves, a desired one-dimensional line lattice can be obtained.
[0052]
As described above, silver, gold, chromium, or the like can be used instead of the aluminum according to the purpose of use of the inorganic polarizing element (claims 6, 7, 8). Of course, other conductive materials can be used.
[0053]
  The inorganic polarizing element 10 whose embodiment has been described with reference to FIG. 2 and subsequent drawings has a substrate 10A made of an inorganic material as a parallel plate.AndCan be used as a "polarizing plate"is there.
[0054]
  Figure 9,Claim 11 shows an embodiment of a polarizing optical element.
  In this polarizing optical element 90, a refractive surface 91A is formed on a portion of the base 91 made of an inorganic material where the one-dimensional line grating 92 is not formed, and the optical action in cooperation with the one-dimensional line grating 92 is achieved.Have.
[0055]
  The refractive surface 92 formed on the surface of the substrate 91 made of an inorganic material opposite to the surface on which the one-dimensional line grating 92 is formed is a “convex lens surface”.AndOn the side of the surface on which the one-dimensional line grating 92 is formed, a convex lens 93 having a flat surface on one side is joined and integrated.Have.
[0056]
In such a polarizing optical element 90, for example, when incident light LI including horizontal and vertical polarization components is incident as a parallel light beam from the convex lens 93 side, the horizontal polarization component becomes transmitted light LT, and the lens 93 and the lens surface 91A As a result, the light beam becomes a focused light beam, and the vertically polarized light component becomes reflected light LR.
[0057]
The lens surface 91A can be a concave lens surface, and the lens 93 can be a concave lens. For example, “transmitted light LT is divergent light and reflected light LR is focused light” or “transmitted light LT is focused light and reflected. It is possible to make the light LR a diverging light or to make both the transmitted light LT and the reflected light LR a diverging light.
[0058]
  FIG.Is a form of liquid crystal elementIt is a figure for demonstrating.
  Reference numerals 101 and 102 denote polarizing optical elements, and reference numeral 103 denotes a liquid crystal element array. The liquid crystal element array is an array of liquid crystal elements LCij constituting a unit pixel arranged in a two-dimensional square matrix, and a driving voltage can be independently applied to each liquid crystal element LCij by a driving circuit (not shown). .
[0059]
Each liquid crystal element LC_ijIs an element based on “twisted nematic liquid crystal”, and when “light in a linearly polarized state” is incident without applying a driving voltage, the polarization plane of incident light is rotated 90 degrees and transmitted. When a driving voltage is applied, the incident light is transmitted while maintaining the direction of the polarization plane.
[0060]
The polarizing optical elements 101 and 102 are configured using an inorganic material as a base, and a one-dimensional line grating made of a conductive material is embedded on one surface thereof, and the exposed portion of the embedded one-dimensional line grating and the flat surface of the base are the same plane. It is formed to make.
[0061]
In the polarizing optical element 101, the embedded one-dimensional line grating 101A has an arrangement direction of the lattice lines in the vertical direction of the drawing. In the polarizing optical element 102, the embedded one-dimensional line grating 102A The arrangement direction is perpendicular to the drawing. Therefore, in the polarizing optical elements 101 and 102, the lattice arrangement directions of the one-dimensional line gratings 101A and 102A are orthogonal to each other.
[0062]
Therefore, the polarizing optical elements 101 and 102 can be used as a pair of polarizing elements as a polarizer / analyzer.
[0063]
Further, on the surface opposite to the one-dimensional line grating 101A of the polarization optical element 101, the microlens ML1 is formed._ijBut liquid crystal element LC_ijThe microlens ML2 is formed on the surface opposite to the one-dimensional line grating 102A of the polarizing optical element 102 formed._ijBut liquid crystal element LC_ijIt is formed corresponding to the array of 1: 1.
[0064]
Therefore, for example, when spontaneously polarized light is incident from the left side of FIG. 10, only the “polarized component that vibrates in the vertical direction in the figure” of the incident light is transmitted by the action of the polarizing optical element 101 as a polarizer. Each microlens ML1 becomes light_ijThe liquid crystal element LC corresponding to each microlens_ijCondensed to This light is liquid crystal element LC_{i j}In this case, in the liquid crystal element to which no driving voltage is applied, the polarization plane is rotated by 90 degrees, and the microlens ML2 is rotated._ijAnd is transmitted through the one-dimensional line grating 102A.
[0065]
Further, in the liquid crystal element to which the driving voltage is applied, the rotation of the polarization plane does not occur, and the microlens ML2_ijThe transmitted light focused by is blocked by the one-dimensional line grating 102A. Thus, the light emitted from the polarizing optical element 102 to the right side of the figure is the liquid crystal element LC to which the drive voltage is applied._ijIs spatially modulated according to
[0066]
A two-dimensional image can be displayed if the light whose intensity is modulated in this way is imaged by an appropriate imaging optical system.
[0067]
Conventionally, an “organic polarizing element” is used as a polarizer / analyzer in a liquid crystal panel. However, it is known that the performance of an organic polarizing element deteriorates due to aging due to the influence of heat. As shown in FIG. 10, when the inorganic polarizing element of the present invention is used as a polarizer / analyzer, the heat resistance and mechanical strength are extremely high, so that a durable liquid crystal panel can be realized.
[0068]
  That is, the polarizing optical elements 101 and 102 shown in FIG. 10 are polarizing optical elements in which a microlens array is formed on the surface of the substrate made of an inorganic material that faces the surface on which the one-dimensional line gratings 101A and 102A are formed.AndMoreover, as a polarizer and an analyzer for the liquid crystal element 103 that can electrically control the polarization direction of transmitted light.Combined,The liquid crystal element array 103 that can electrically control the polarization direction of transmitted light for each element is combined as a polarizer and an analyzer, and the arrangement of microlenses in the polarizing optical elements 101 and 102 is the same as that of the liquid crystal element array 103. Array array andMatch.
[0069]
    "Concrete example"
  The polarizing optical elements 101 and 102 shown in FIG. 10 were prepared as follows. Wavelength used: λ is visible region: 400 to 700 nm, parallel plate-shaped optical glass having a refractive index of 1.4 is used as an inorganic material to be a base, and a convex surface corresponding to the element arrangement in the liquid crystal element array is provided on one side thereof. A substrate formed with an array of microlenses was used.
[0070]
  Aluminum was used as the conductive material constituting the one-dimensional line grating, the arrangement pitch of the grating lines: d was 85.7 nm, and the parameters were n · d / λ <0.3. That is, for λ = 400 nm, n · d <120nmIt is.
[0071]
The cross section of the lattice line was rectangular, its width: a = 30 nm, and thickness: t = 100 nm.
[0072]
As described above, “a photoresist layer is formed on the flat surface of the optical glass, a pattern corresponding to a one-dimensional line lattice is written on the photoresist layer by electron beam drawing, development is performed, and etching is performed. A groove pattern corresponding to a one-dimensional line lattice is formed on the substrate, and aluminum is deposited in a layer form by CVD. Thereafter, the photoresist layer to which aluminum is deposited is removed from the flat surface of the optical glass, and the surface side of the optical glass is blasted. The method is such that the exposed portion of the embedded aluminum one-dimensional line lattice and the flat surface of the substrate are in the same plane ”.
[0073]
In the polarizing optical elements 101 and 102 thus obtained, the transmittance of horizontal polarization and vertical polarization is as shown in FIG. 11, and the extinction ratio is as shown in FIG.
As apparent from FIG. 11, in the visible region: wavelength range of 400 to 700 nm, the transmittance is substantially 0 for vertically polarized light and 80% or more for horizontally polarized light. Further, the extinction ratio is 1: 100 or more in the visible region.
[0074]
That is, this polarizing optical element can be used as a good polarizer / analyzer.
[0075]
【The invention's effect】
  As described above, according to the present invention,Realization of new polarization opticsit can.Inorganic polarizing elementAs described above, a one-dimensional line grating made of a conductive material is embedded in a flat surface of a transparent substrate made of an inorganic material, and the exposed portion of the embedded one-dimensional line grating and the flat surface of the substrate are the same plane. Because of the structure, the bond between the one-dimensional line lattice and the substrate made of an inorganic material is firm and excellent in mechanical durability, and since the material is an inorganic material and a conductive material, it is also excellent in heat resistance. ing. Moreover, it has a favorable polarizing function by satisfying the condition (1).
[0076]
  Therefore,This inorganic polarizing elementUsePolarizing opticsExcellent polarization function,Combines polarization and other optical functions,The effect of heat is not a problem.
[Brief description of the drawings]
[Figure 1]Inorganic polarizing elementIt is a figure for demonstrating the structure of.
[Figure 2]One form of inorganic polarizing elementIt is a figure for demonstrating.
FIG. 3 is a diagram for explaining a condition (1).
FIG. 4 is a diagram for explaining conditions (2) and (3).
FIG. 5 is a diagram for explaining conditions (2) and (3).
FIG. 6 is a diagram for explaining conditions (2) and (3).
FIG. 7 is a diagram for explaining conditions (2) and (3).
FIG. 8 is a diagram showing three examples of cross-sectional shapes of lattice lines of a one-dimensional line lattice.
FIG. 9Claim 1It is a figure for demonstrating one Embodiment of the polarizing optical element of this.
FIG. 10One form of liquid crystal elementIt is a figure for demonstrating.
FIG. 11Polarizing optical element for liquid crystal polarizing elementIt is a figure for demonstrating the optical characteristic.
FIG. 12 is a diagram for explaining optical characteristics of Examples.
[Explanation of symbols]
1 Substrate made of inorganic material
1A Flat surface of substrate 1
2i Lattice lines of a one-dimensional line grating made of a conductive material embedded in the flat surface 1A of the substrate 1

Claims (8)

A one-dimensional line grating made of a conductive material is embedded in a flat surface of a transparent substrate made of an inorganic material so that the exposed portion of the embedded one-dimensional line grating and the flat surface of the substrate make the same plane. Formed,
The refractive index of a transparent substrate made of an inorganic material: n, the arrangement pitch of each lattice line of a one-dimensional line lattice made of a conductive material: d, and the wavelength of light: λ are as follows:
(1) 0 <n · d / λ <0.7
Satisfied ,
A lens surface is formed on the surface of the substrate made of the inorganic material opposite to the surface on which the one-dimensional line grating is formed, and one surface is flat on a flat surface in which the one-dimensional line grating is embedded. A polarizing optical element obtained by joining and integrating lenses. The polarizing optical element according to claim 1,
The cross-sectional shape of each lattice line in the one-dimensional line lattice made of a conductive material is rectangular, the refractive index of the transparent substrate made of inorganic material: n, and the arrangement pitch of each lattice line of the one-dimensional line lattice made of the conductive material: d, the wavelength of light: parameter by λ: the value of n · d / λ is 0.1, and the width: a, the thickness: t, the refractive index in the rectangular shape of the cross-sectional shape of each lattice line : N, arrangement pitch: d, wavelength: λ, conditions:
(2) 0 <a <d
(3) 0 <t <0.22λ / n
A polarizing optical element characterized by satisfying The polarizing optical element according to claim 1,
A polarizing optical element, wherein a cross-sectional shape of each lattice line in a one-dimensional line lattice made of a conductive material is a trapezoidal shape, a wedge shape, a semicircular shape, or a semielliptical shape. The polarizing optical element according to claim 1, 2 or 3,
A polarizing optical element, wherein the conductive material constituting the one-dimensional line grating is a metal. The polarizing optical element according to claim 4, wherein
A polarizing optical element, wherein the metal constituting the one-dimensional line grating is any one of aluminum, silver, gold, and chromium. The polarizing optical element according to claim 5, wherein
For light in the visible region, it is used as a polarizing element that reflects the non-transmitted light, the polarizing optical element, characterized in that one-dimensional line grating is made of aluminum or silver. The polarizing optical element according to claim 5, wherein
For light in the visible range, the non-transmitted light is used as a polarizing element that does not reflect light polarizing film 1-dimensional line grating, characterized in that it is formed of chromium. The polarizing optical element according to claim 5, wherein
To light in the near infrared region, it is used as a polarizing element that reflects the non-transmitted light, the polarizing optical element, characterized in that one-dimensional line grating is formed of gold.

Images