JP2008299178A - Polarizing element, manufacturing method of polarizing element, liquid crystal device, and projection display device - Google Patents

Abstract

The present invention provides a polarizing element, a manufacturing method of the polarizing element, a liquid crystal device, and a projection display device that have excellent optical characteristics, can reduce the number of components, and can realize high functionality of the liquid crystal device.
A substrate 11A, a plurality of fine metal wires 18A provided on the substrate 11A by patterning a metal film by etching, and an etching gas and an etching product at the time of etching the metal film cause a chemical reaction between the fine metal wires. The polarizing element 1 includes a deposited film 118 formed on the upper end of 18A. The deposited film 118 is larger than the width of the thin metal wire 18A.
[Selection] Figure 1

Description

  The present invention relates to a polarizing element, a method for manufacturing a polarizing element, a liquid crystal device, and a projection display device.

  A liquid crystal device is used as a light modulation device in a projection display device such as a projector. As such a liquid crystal device, one having a structure in which a liquid crystal layer is sandwiched between a pair of opposed substrates is known, and a voltage is applied to the liquid crystal layer inside the pair of substrates. An electrode is formed. Further, an alignment film that controls the alignment of liquid crystal molecules when no voltage is applied is formed inside the electrode, and an alignment film that has been subjected to rubbing treatment on the surface of a polyimide film is known.

On the other hand, a polarizing plate is disposed on the outside of the pair of substrates (a surface side different from the surface facing the liquid crystal layer) so that predetermined polarized light is incident on the liquid crystal layer. As a polarizing plate, in addition to a polarizing film produced by orienting iodine or a dichroic dye in a certain direction by stretching a resin film of an organic compound in one direction, a metal is formed on a transparent substrate (glass substrate). There is known a wire grid type polarizing plate having a configuration in which a grid made of
The most important feature of this wire grid type polarizing plate is that it is made of an inorganic material and has excellent durability. As such a wire grid, for example, techniques such as Patent Documents 1 and 2 are disclosed.
Special Table 2003-519818 Japanese translation of PCT publication No. 2002-520777

  Recently, a technique for incorporating a wire grid type polarizing plate into a liquid crystal panel as well as a single unit has been proposed. As described above, the incorporation of the polarizing element greatly contributes to the reduction of the number of parts and the enhancement of the function of the liquid crystal panel. Moreover, it is known that the optical characteristics of the wire grid type polarizing element are affected by the material interposed between the grids (conductive members), and a material having a refractive index of 1 between the grids, that is, air ( Alternatively, a state in which a vacuum atmosphere) is interposed is desirable.

  Patent Document 1 described above pays attention to the material between the grids, and can have a structure in which air (or vacuum) is enclosed. However, when the polarizing element of Patent Document 1 is arranged in the cell, it is feasible from the point that the cover glass must be installed only in the pixel region and the cell thickness is increased by arranging the cover glass. Is extremely low. Furthermore, Patent Document 1 does not mention a specific manufacturing method. Patent Document 2 discloses a technique incorporating a wire grid type polarizing element. However, since the gap between the grids is embedded with a planarizing layer, the optical characteristics may be lowered.

  The present invention has been made in view of such circumstances, and has a superior optical characteristic, a polarizing element capable of realizing a reduction in the number of parts and a high functionality of a liquid crystal device, a manufacturing method of the polarizing element, An object of the present invention is to provide a liquid crystal device and a projection display device.

  In order to solve the above-described problems, a polarizing element of the present invention includes a substrate, a plurality of thin metal wires provided on the substrate by patterning the metal film by etching, and an etching gas and etching generation during the etching of the metal film. A deposited film formed on the upper end of each of the thin metal wires by a chemical reaction of the material, wherein the deposited film is larger than the width of the thin metal wire.

  According to the polarizing element of the present invention, the gap in the upper part of the thin metal wire is narrowed by the deposited film. For example, even when another material is laminated on the deposited film, the deposited film prevents the penetration between the fine metal wires and has optical characteristics equivalent to the state in which the fine metal wires are open to the atmosphere. Obtainable. Therefore, even when the polarizing element is incorporated in the liquid crystal device, it does not fill with another member such as a liquid crystal layer or an alignment film between the fine metal wires and has excellent optical characteristics.

The polarizing element has a coating layer provided on each deposited film, and is surrounded by the adjacent metal thin wires, the deposited film formed on the metal thin wires, the substrate, and the coating layer. Preferably, the area is a space.
According to this configuration, a space in which air (or vacuum) is sealed between the fine metal wires can be configured by the deposited film, and excellent optical characteristics are provided.

Moreover, in the said polarizing element, it is preferable that the deposited film formed on the said adjacent metal fine wire contact | abuts mutually.
According to this configuration, the deposited films on the adjacent fine metal wires are in contact with each other, so that a space in which air (or vacuum) is enclosed between the fine metal wires can be formed, and the optical properties are excellent. Become.

  The manufacturing method of the polarizing element of the present invention is a manufacturing method of a polarizing element in which a metal film is formed on a substrate, and the metal film is patterned by dry etching to form a plurality of fine metal wires on the substrate. Forming a metal film thereon, forming a mask on the metal film, etching the metal film halfway with a first etching gas through the mask, etching products and chemicals of the metal film A second etching gas that causes a reaction is added to the first etching gas and the metal film is etched to pattern the metal fine wire, and a deposited film larger than the width of the metal fine wire is formed at the upper end of the metal fine wire. And a step of performing.

  According to the present invention, the second etching gas chemically reacts with the etching product of the metal film, so that the deposited film formed at the upper end of the metal thin line narrows the gap above the metal thin line. Even in the case of laminating these materials, it is possible to obtain a material having optical characteristics equivalent to the state in which the deposited film prevents entry between the fine metal wires and the fine metal wires are open to the atmosphere. Therefore, even when the polarizing element is incorporated in the liquid crystal device, it is possible to provide a polarizing element having excellent optical characteristics without filling another member such as a liquid crystal layer or an alignment film between the thin metal wires.

In the method for manufacturing a polarizing element, it is preferable to use a gas containing C and F elements as the second etching gas and use Al as the metal film.
In this way, the above-described deposited film can be satisfactorily formed on the thin metal wire.

Further, in the method for manufacturing a polarizing element, the step of forming, on the deposited film, the adjacent fine metal wires, the deposited film formed on the fine metal wires, and a coating layer forming a space between the substrates. It is preferable to have.
In this way, a space in which air (or vacuum) is sealed between the fine metal wires is formed by the deposited film, and a polarizing element having excellent optical characteristics can be manufactured.

Moreover, in the manufacturing method of the said polarizing element, it is preferable to pattern the said metal fine wire from the said metal film so that the deposition film formed on the said adjacent metal fine wire may become the space | interval which mutually contacts.
In this way, since the deposited films on the adjacent metal thin wires are in contact with each other, a polarizing element having excellent optical characteristics can be provided by forming a space in which air (or vacuum) is sealed between the metal thin wires.

  A liquid crystal device according to the present invention includes the polarizing element.

  According to the liquid crystal device of the present invention, since the polarizing element having excellent optical characteristics is provided, a liquid crystal device having excellent reliability can be provided.

In the liquid crystal device, it is preferable that a liquid crystal layer is sandwiched between a pair of substrates, and the polarizing element is formed on the liquid crystal layer side of at least one of the pair of substrates.
In this way, since the polarizing element having excellent optical characteristics is built in, the liquid crystal device itself can be thinned.

  A projection display device according to the present invention is characterized in that the liquid crystal device is provided as a light modulation device.

  According to the projection type display device of the present invention, light modulation can be favorably performed by a liquid crystal device having excellent optical characteristics, so that display with high accuracy and high luminance can be performed.

(First embodiment)
DESCRIPTION OF EMBODIMENTS Hereinafter, a polarizing element manufacturing method and a polarizing element according to an embodiment of the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size.

(Polarizing element)
Fig.1 (a) is a fragmentary sectional view which shows the polarizing element 1 of this embodiment. FIG. 1B is a perspective view showing a polarizing element unit 110 constituting the polarizing element.
The polarizing element 1 includes a substrate 11A, a wire grid polarizing layer 18 formed on the surface of the substrate 11A, and a coating layer 117 provided on the substrate via the wire grid polarizing layer 18.

  The substrate 11A is made of a translucent material such as glass or quartz. A plurality of metal protrusions 18A (thin metal wires) that protrude upward and are parallel to each other are formed on the substrate 11A.

  The wire grid polarizing layer 18 has a plurality of metal protrusions 18A partially disposed on the substrate 11A. The metal protrusion 18A has a striped pattern in plan view, and has a width W of 70 nm, a height H of 100 nm, and a pitch P of 140 nm, for example.

  The metal protrusion 18A is formed by etching and patterning a metal film as will be described in detail later. In the present embodiment, aluminum (Al) is used as the metal material constituting the metal film.

The metal protrusion 18A is provided with a deposition film (deposited film) 118 formed by a chemical reaction between an etching gas and an etching product when the metal film is etched. The deposition film 118 functions as a protective film for protecting the metal protrusion 18A.
A silicon oxide (SiO ₂ ) (not shown) used in a manufacturing process described later is formed on the metal protrusion 18A. This silicon oxide is used as a mask M when the metal film 12a is etched (see FIG. 4).

  The coating layer 117 covers the plurality of metal protrusions 18A (deposition film 118) and is arranged on the upper surface side thereof. In the present embodiment, the thickness of the coating layer 117 is 20 to 30 nm, and is appropriately set according to the height, pitch, and the like of the metal protrusions 18A. The covering layer 117 is formed by sputtering a silicon oxide film.

In general, the optical characteristics of a polarizing element change depending on the refractive index between metal protrusions.
Hereinafter, the point that the optical characteristics of the polarizing element depend on the refractive index between the metal protrusions will be described with reference to the drawings.
FIG. 2A is a graph and a schematic configuration diagram showing optical characteristics (transmittance and contrast) in a configuration in which a wire grid polarizing element is released in the atmosphere (the refractive index between metal protrusions is 1).
FIG. 2B is a graph and schematic configuration diagram showing optical characteristics when a polarizing element is mounted in a liquid crystal device and liquid crystal (refractive index 1.6) is filled between metal protrusions. It is. In the configuration shown in FIG. 2B, since the tip end side in the thickness direction of the metal protrusions is opened, the liquid crystal is filled between the metal protrusions.
FIG. 2C is a graph and a schematic configuration diagram showing optical characteristics when a coating film (SiO ₂ ) is formed between the metal protrusion and the liquid crystal and the liquid crystal is arranged thereon.

  The graphs shown in FIGS. 2A to 2C show linearly polarized light having a vibration direction perpendicular to the extending direction of the metal film with respect to the polarizing element under the above conditions (that is, on the transmission axis of the polarizing element). The result of measuring the transmittance (Tp) with the incident linearly polarized light in the vibration direction, the transmittance (Tp) of the linearly polarized light in the vibration direction parallel to the transmission axis of the polarizing element, and the reflection axis of the polarizing element The measurement result of contrast (Tp / Ts) obtained as a ratio with the transmittance | permeability (Ts) of the linearly polarized light of a parallel vibration direction is shown. As a polarizing element, the larger the value of both of these (transmittance and contrast), the better the performance.

As shown in FIG. 2A, it can be seen that a polarizing element having a metal protrusion opened in the atmosphere has good characteristics in the visible range.
On the other hand, under the condition where the liquid crystal is filled in the opening of the metal film shown in FIG. 2B, the uniformity of transmittance in the visible light region is lowered, particularly in the blue region (near 440 nm). The depression is intense. Therefore, it is shown that the optical characteristics are deteriorated when the space between the metal protrusions is filled with a substance having a high refractive index.
On the other hand, the polarizing element having the structure shown in FIG. 2C prevents the liquid crystal from being filled between the metal protrusions by the coating film (SiO ₂ ), and the state in which the space between the metal protrusions is filled with air (or Vacuum state). With this configuration, although the wire grid polarizing element is arranged in the liquid crystal, the transmittance and contrast are not reduced as compared with the structure shown in FIG. 2B, and the structure shown in FIG. It is possible to obtain good optical characteristics that are comparable to the above.

  By the way, the polarizing element 1 of this embodiment has the deposition film 118 formed on the metal protrusion 18A. Therefore, the void on the upper end side of the metal protrusion 18A is narrowed by the deposition film 118.

  Therefore, the coating film 117 formed on the deposition film 118 is in a state of closing the space between the metal protrusions 18A without being filled between the metal protrusions 18A. In the polarizing element 1 of the present embodiment, as shown in FIG. 1, the region surrounded by the adjacent metal protrusions 18A, the deposition film 118 formed on the metal protrusions 18A, the substrate 11A, and the covering layer 117 is formed. A hollow portion 18B is configured. Air (or vacuum) is sealed in the hollow portion 18B, so that good optical characteristics can be obtained as described above.

  As described above, in the polarizing element 1 of the present embodiment, the gap on the upper end side of the metal protrusion 18A is narrowed by the deposition film 118 formed on the upper end of the metal protrusion 18A. It is provided with a hollow portion 18B in which air (or vacuum) is sealed without being filled between the bodies 18A. Therefore, even when the polarizing element 1 is incorporated in the liquid crystal device as will be described later, it has good optical characteristics as in the structure shown in FIG.

(Polarizing element manufacturing method)
Next, the manufacturing method of the polarizing element 1 described above will be described with reference to FIG. FIG. 3 is a cross-sectional view showing the manufacturing process of the polarizing element 1.

First, as shown in FIG. 3A, a substrate 11A made of a transparent glass substrate or the like is prepared, and a solid metal film 12a made of aluminum (Al) is formed on one surface side of the substrate 11A. Subsequently, a solid mask layer m made of an inorganic material (SiO ₂ ) functioning as a hard mask is formed on the metal film 12a in a subsequent dry etching process.

  As a method of forming the metal film 12a and the mask layer m, a film forming method such as an evaporation method or a sputtering method can be used. In addition, as a metal constituting the metal film 12a, other than aluminum, for example, gold, copper, palladium, platinum, rhodium, silicon, nickel, cobalt, manganese, iron, chromium, titanium, ruthenium, niobium, neodymium, ytterbium, Any of yttrium, molybdenum, indium, bismuth, or an alloy thereof can be used.

  Next, as shown in FIG. 3B, a resist material is applied onto the mask layer m by spin coating, and this is pre-baked to form a resist layer 14a. Next, the resist layer 14a is exposed by, for example, a two-beam interference exposure method using laser light having a wavelength of 266 nm as exposure light. Here, exposure is performed so that the pitch is a fine striped pattern having a wavelength equal to or smaller than the wavelength of visible light (for example, 140 nm). After the exposure, the resist layer 14a is further baked (PEB), and then the resist layer 14a is developed. Thereby, as shown in FIG. 3C, a resist 14 having a striped pattern is formed on the mask layer m.

  Here, as an exposure apparatus that performs the two-beam interference exposure method, for example, the one shown in FIG. 5 can be used. The exposure apparatus 120 includes a laser light source 121 that irradiates exposure light, a diffraction beam splitter 122, a monitor 123, beam expanders 124 and 125, mirrors 126 and 127, and a stage 128 on which the substrate 11A is placed. I have.

  The laser light source 121 is, for example, an Nd: YVO4 laser device having a fourth harmonic wavelength of 266 nm. The diffractive beam splitter 122 is a branching unit that splits one laser beam output from the laser light source 121 to generate two laser beams. The diffractive beam splitter 122 is configured to generate two diffracted beams (± first order) having the same intensity when the incident laser beam is TE polarized light. The monitor 123 receives the light emitted from the diffractive beam splitter 122 and converts it into an electrical signal. The exposure apparatus 120 can adjust the crossing angle of the two laser beams based on the converted electrical signal.

The beam expander 124 includes a lens 124a and a spatial filter 124b, and has a configuration in which one of the two laser beams branched by the diffractive beam splitter 122 is expanded to, for example, about 300 mm. . Similarly, the beam expander 125 also includes a lens 125a and a spatial filter 125b, and is configured to increase the other beam diameter of the two laser beams. The mirrors 126 and 127 are configured to reflect the laser beams transmitted through the beam expanders 124 and 125 toward the stage 128, respectively. Here, the mirrors 126 and 127 generate interference light by crossing the reflected laser beams, and irradiate the resist layer 14a on the substrate 11A with the interference light.
By irradiating the resist layer 14 a with interference light using such an exposure apparatus 120, the resist 14 can be formed with a formation pitch narrower than the wavelength of the laser light source 121.

  Next, dry etching is performed through the resist 14 to pattern the mask layer m, thereby forming a mask M as shown in FIG. The resist 14 may be removed after the mask M is formed. Even if the resist 14 is not peeled off, there is no problem because it is removed by etching during the patterning of the metal film 12a described later.

Subsequently, the metal film 12a is patterned through the mask M. First, a first etching step is performed in which the metal film 12a is etched halfway by dry etching using boron trichloride (BCl ₃ ) and chlorine (Cl ₂ ) as an etching gas (first etching gas). As conditions for the first etching step, for example, the output is RF: ICP / Bias (300/200 W), the flow rate of BCl ₃ gas to be used is 20 sccm, the flow rate of Cl ₂ gas is 40 sccm, the pressure is 0.7 Pa, and the etching time. Was 17 seconds.

After the metal film 12a is etched halfway (after completion of the first etching process), as shown in FIG. 4A, C and F are used as the second etching gas in the first etching gas (BCl ₃ , Cl ₂ ). A gas containing an element, for example, trifluoromethane (CHF ₃ ) is added and a second etching process is performed in which the metal film 12a is etched to pattern the metal protrusion 18A. As conditions for the second etching step, for example, the output is RF: ICP / Bias (300/200 W), the flow rate of BCl ₃ gas to be used is 20 sccm, the flow rate of Cl ₂ gas is 40 sccm, the flow rate of CHF ₃ is ₃ sccm, and the pressure Was 0.7 Pa and the etching time was 20 seconds.

  At this time, with the progress of the etching of the metal film 12a, as shown in FIG. 4B, the etching reaction of the etching product of the metal film 12a on the upper end side (the side where the mask M is formed) of the metal film 12a. The deposition film 118 begins to be deposited. Since the mask M is formed on the metal film 12a, the deposition film 118 is formed on the upper end portion of the metal film 12a by covering the mask M.

The deposition film 118 is a deposit containing each element constituting Al etched from the metal film 12a and etching gases BCl ₃ , Cl ₂ , and CHF ₃ . Further, CHF ₃ (second etching gas) does not function as an etching gas, and only functions to form the deposition film 118. Note that the second etching gas is not limited to CHF ₃ , and CF ₄ , C ₄ F _8, or the like may be added to the first etching gas.

When the deposition film 118 starts to be deposited, as shown in FIG. 4C, the entrance path of the etching gas (BCl ₃ , Cl ₂ ) on the upper end side of the metal film 12a is narrowed by the deposition film 118 and the etching rate is lowered. However, etching proceeds anisotropically. As a result, the metal projection 18A can be satisfactorily patterned, and the deposition film 118 can be formed on the upper end of the metal projection 18A as shown in FIG. 4 (d). The gap at the top of the metal protrusion 18A is narrowed by the deposition film 118.

  FIG. 6 is an electron micrograph of the metal protrusion 18A manufactured using the manufacturing method of the present embodiment. As shown in FIG. 6, the metal protrusion 18 </ b> A obtained by the present embodiment has a deposition film 118 formed on the upper end thereof. Thus, according to the manufacturing method of the present embodiment, the wire grid polarizer 18 in which the gap on the upper side of the metal protrusion 18A is narrowed by the deposition film 118 can be provided.

  Next, the coating layer 117 shown in FIG. 1 is formed by forming a silicon oxide film on the metal protrusion 18A (wire grid polarizer 18) using a sputtering method or the like. At this time, the metal protrusion 18A is formed. Since the gap on the upper side of the metal protrusion 18A is narrowed by the deposition film 118 formed on the upper end of the metal film, the coating layer 117 is not filled between the metal protrusions 18A and is not filled on the deposition film 118. The grown crystal grains abut on the upper part of the opening region between the metal protrusions 18A to close the opening end of the opening. Thereafter, deposits (sputtered particles or the like) forming the coating layer 117 cannot enter the opening, and the coating layer 117 is formed on the metal protrusion 18A in a state where the opening is hollow. The The wire grid polarizing layer 18 in which the region surrounded by the adjacent metal protrusions 18A, the deposition film 118 formed on the metal protrusions 18A, the substrate 11A, and the coating layer 117 constitutes the cavity 18B by the above process. Can be manufactured. According to such a polarizing element 1, the space between the metal protrusions 18A of the wire grid polarizing layer 18 is not filled with the liquid crystal, the alignment film, or the like even when mounted inside the liquid crystal device as described later, and the optical characteristics. Will not drop. Therefore, even when the polarizing element 1 is incorporated in the liquid crystal device as will be described later, it has excellent optical characteristics without being filled with another member such as a liquid crystal layer or an alignment film between the thin metal wires.

(Modification)
As shown in FIG. 7, the etching conditions (first and second etching steps) of the metal film 12a may be adjusted so that the deposition films 118 on the adjacent metal protrusions 18A come into contact with each other. In this case, a space in which air (or vacuum) is enclosed between the metal protrusions 18A can be formed without forming the coating layer 117. Therefore, even when mounted inside a liquid crystal device as described later, the optical characteristics are not deteriorated, and the coating layer 117 is not provided, so that the liquid crystal device can be thinned. Further, even when the deposition film 118 on the adjacent metal protrusion 18A is close and the gap on the upper end side of the metal protrusion 18A is very small (for example, about several nm), the coating layer 117 is not formed. Also good. In this case, since the gap between the deposition films 118 is very small, the liquid crystal and the alignment film are not filled between the metal protrusions 18A, and the optical characteristics can be prevented from deteriorating.

(projector)
FIG. 8 is a schematic configuration diagram showing a main part of a projector as an embodiment of the projection display apparatus of the present invention. The projector according to the present embodiment is a liquid crystal projector using a liquid crystal device as a light modulation device.

  In FIG. 8, 810 is a light source, 813 and 814 are dichroic mirrors, 815, 816 and 817 are reflection mirrors, 818 is an incident lens, 819 is a relay lens, 820 is an exit lens, and 822, 823 and 824 are liquid crystal devices. A modulation device, 825 is a cross dichroic prism, and 826 is a projection lens.

  The light source 810 includes a lamp 811 such as a metal halide and a reflector 812 that reflects the light of the lamp. As the light source 810, besides a metal halide, an ultrahigh pressure mercury lamp, a flash mercury lamp, a high pressure mercury lamp, a deep UV lamp, a xenon lamp, a xenon flash lamp, or the like can be used.

  The dichroic mirror 813 transmits red light contained in white light from the light source 810 and reflects blue light and green light. The transmitted red light is reflected by the reflection mirror 817 and is incident on the liquid crystal light modulation device 822 for red light. The green light reflected by the dichroic mirror 813 is reflected by the dichroic mirror 814 and is incident on the liquid crystal light modulation device 823 for green light. Further, the blue light reflected by the dichroic mirror 813 passes through the dichroic mirror 814. For blue light, in order to prevent light loss due to a long optical path, a light guide unit 821 including a relay lens system including an incident lens 818, a relay lens 819, and an output lens 820 is provided. The blue light is incident on the blue light liquid crystal light modulation device 824 via the light guide unit 821.

  The three color lights modulated by the respective light modulation devices 822 to 824 are incident on the cross dichroic prism 825. This cross dichroic prism 825 is formed by bonding four right-angle prisms, and a dielectric multilayer film reflecting red light and a dielectric multilayer film reflecting blue light are formed in an X shape at the interface. Yes. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the screen 827 by the projection lens 826 which is a projection optical system, and the image is enlarged and displayed.

  Here, in the projector of the present embodiment, a liquid crystal device as shown in FIG. 9 is employed as the light modulation devices 822 to 824.

(Liquid crystal device)
FIG. 9 is a schematic cross-sectional view of the liquid crystal devices 822 to 824, and the liquid crystal devices 822 to 824 have a configuration in which the liquid crystal layer 50 is sandwiched between the pair of substrates 10 and 20.

  The substrate 10 is an element substrate, and has a configuration in which a wire grid polarizing layer 18, a pixel electrode 9, and an alignment film 21 are provided on a substrate body 10A. The substrate 10 includes a TFT element (not shown) that performs switching driving of voltage application to the pixel electrode 9. On the other hand, the substrate 20 is a counter substrate, and includes a wire grid polarizing layer 18, a counter electrode 23, and an alignment film 22 on the substrate body 20A.

  In the present embodiment, a wire grid type polarizing element 19 is configured by the wire grid polarizing layer 18 and the substrate body 10A (20A). The substrate bodies 10A and 20A are not only substrates for liquid crystal devices but also function as substrates for polarizing elements. The polarizing element 19 is manufactured using the manufacturing method of the polarizing element described above.

  As the alignment films 21 and 22 formed on the wire grid type polarizing element 19, for example, an organic material such as polyimide subjected to a rubbing process is used.

  In the configuration of FIG. 9, a pair of substrates 10 and 20 are bonded together via a sealing material (not shown), and liquid crystal is sealed therein. In this case, a TN (Twisted Nematic) mode is employed as the liquid crystal mode of the liquid crystal layer 50, but an STN (Super Twisted Nematic) mode, an ECB (Electrically Controlled Birefringence) mode, and the like can also be employed.

  Here, the wire grid polarizing layer 18 provided on the substrate 10 side and the wire grid polarizing layer 18 provided on the substrate 20 side are configured such that the metal protrusions 18A intersect each other.

With such a wire grid polarizing layer 18, it is possible to select each color light emitted from the light source 810 and transmit only linearly polarized light to the liquid crystal layer 50.
The wire grid polarizing layer 18 includes a large number of metal protrusions 18A arranged in a stripe pattern with a pitch smaller than the wavelength of light incident on the liquid crystal layer 50, thereby extending the metal protrusions 18A in the extending direction. On the other hand, it can function as a reflective polarizing element that reflects polarized light that vibrates in a substantially parallel direction and transmits polarized light that vibrates in a direction substantially perpendicular to the extending direction of the metal protrusion 18A.

  That is, the wire grid polarization layer 18 is subjected to polarization selection according to the polarization direction of the light incident on the wire grid polarization layer 18. Therefore, as shown in FIG. 10, the linearly polarized light X having the polarization axis in the direction perpendicular to the extending direction of the wire grid polarizing layer 18 is transmitted, and the polarization axis is parallel to the extending direction of the wire grid polarizing layer 18. The linearly polarized light Y having

  Therefore, the wire grid polarization layer 18 has the same function as the light reflection type polarizer, that is, the function of transmitting polarized light parallel to the optical axis (transmission axis) and reflecting the polarized light perpendicular thereto.

  In the liquid crystal devices 822 to 824, linearly polarized light is incident on the liquid crystal layer 50 through the wire grid polarizing layer 18 incorporated inside the substrate 10 (20) as described above, and phase control is performed in the liquid crystal layer 50. Is done. That is, the drive control of the liquid crystal layer 50 is performed by the voltage applied to the electrodes 9 and 23, and the phase of the incident light is controlled. Therefore, the phase-controlled light is selectively transmitted through the wire grid polarizing layer 18 incorporated inside the opposite substrate 20 (10) and modulated. As described above, the wire grid polarizing layer 18 according to the present embodiment is not filled with the alignment films 21 and 23 and the liquid crystal 50 between the metal protrusions 18A, and has excellent optical characteristics. ing.

  In this embodiment, since the polarizing element is incorporated in the liquid crystal panel, the substrate bodies 10A and 20A function as the substrate for the liquid crystal device and the substrate for the polarizing element. Thereby, since the number of parts can be reduced, the whole apparatus can be thinned and the function of the liquid crystal device can be improved. Furthermore, since the device structure is simplified, the cost can be reduced.

  Also, as shown in FIG. 8, each color light modulated by the liquid crystal devices 822 to 824 is formed by being incident on the cross dichroic prism 825 as described above. The synthesized light is projected onto the screen 827 by the projection lens 826 which is a projection optical system, and the image is enlarged and displayed.

The projector 800 includes a liquid crystal device incorporating a polarizing element as light modulation means.
As described above, since the liquid crystal devices 822 to 824 of the present embodiment have the wire grid polarizing layer 18 with high optical characteristics as described above, display defects and reliability are not reduced, and low power consumption is achieved. The display brightness is also excellent. Therefore, since the projector 800 according to the present invention includes the liquid crystal devices 822 to 824 as light modulation means, the projector 800 has high reliability and excellent display characteristics.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and includes those in which various modifications are made to the above-described embodiment without departing from the spirit of the present invention. For example, in the embodiment, a liquid crystal device including a TFT as a switching element has been described as an example. However, the present invention is applied to a liquid crystal device including a two-terminal element such as a thin film diode as a switching element. Is also possible. In the embodiment, a three-plate projector (projection display device) has been described as an example. However, the present invention can also be applied to a single-plate projection display device or a direct-view display device.

  The liquid crystal device of the present invention can also be applied to electronic devices other than projectors. A specific example is a mobile phone. This mobile phone includes the liquid crystal device according to each of the above-described embodiments or modifications thereof in a display unit. Other electronic devices include, for example, IC cards, video cameras, personal computers, head-mounted displays, fax machines with display functions, digital camera finders, portable TVs, DSP devices, PDAs, electronic notebooks, and electronic bulletin boards. And advertising announcement displays.

It is the fragmentary sectional view and perspective view which show a polarizing element. The graph and schematic block diagram which show the change of the optical characteristic of a polarizing element by the difference in structure. It is manufacturing process explanatory drawing of a polarizing element. FIG. 4 is an explanatory diagram of a manufacturing process of the polarizing element subsequent to FIG. 3. It is a schematic block diagram which shows an example of the exposure apparatus used for manufacture of a polarizing element. It is a photograph which shows the cross-sectional structure of a polarizing element, and the conventional structure. It is a figure which shows the structure which concerns on the modification of a polarizing element. It is a schematic block diagram which shows a projector. It is a schematic block diagram of the liquid crystal device used as a light modulation apparatus. It is explanatory drawing which shows the effect | action of a polarizing layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Polarizing element, 11A ... Board | substrate, 12a ... Metal film, 18A ... Metal protrusion (metal fine wire), 19 ... Polarizing element, 117 ... Cover film, 118 ... Deposition film (deposition film), 800 ... Projector (projection type) Display device), 822-824 ... Liquid crystal device

Claims (10)

A substrate, a plurality of fine metal wires provided on the substrate by patterning the metal film by etching, and an etching gas and an etching product at the time of etching the metal film are chemically reacted with each other at the upper end portion of each of the fine metal wires. A deposited film formed, and
The polarizing element, wherein the deposited film is larger than the width of the thin metal wire.   A coating layer is provided on each deposited film, and the adjacent metal thin wires, the deposited film formed on the metal thin wires, the substrate, and a region surrounded by the coating layer are spaces. The polarizing element according to claim 1.   The polarizing element according to claim 1, wherein the deposited films formed on the adjacent metal thin wires are in contact with each other. A method for manufacturing a polarizing element, comprising: forming a metal film on a substrate; and patterning the metal film by dry etching to form a plurality of fine metal wires on the substrate,
Forming the metal film on the substrate;
Forming a mask on the metal film, and etching the metal film halfway with a first etching gas through the mask;
A second etching gas that causes a chemical reaction with an etching product of the metal film is added to the first etching gas and the metal film is etched to pattern the metal fine wire, and the metal fine wire is formed at an upper end portion of the metal thin wire. Forming a deposited film that is larger than the width of the polarizing element.   The method for manufacturing a polarizing element according to claim 4, wherein a gas containing C and F elements is used as the second etching gas, and Al is used as the metal film.   6. The method according to claim 4, further comprising: forming a coating layer forming a space between the adjacent metal thin wires, the deposited film formed on the metal thin wires, and the substrate on the deposited film. The manufacturing method of the polarizing element of description.   6. The method for manufacturing a polarizing element according to claim 4, wherein the thin metal wires are patterned from the metal film so that the deposited films formed on the adjacent thin metal wires are in contact with each other. .   A liquid crystal device comprising the polarizing element according to claim 1.   9. The liquid crystal device according to claim 8, wherein a liquid crystal layer is sandwiched between a pair of substrates, and the polarizing element is formed on the liquid crystal layer side of at least one of the pair of substrates. .   A projection display device comprising the liquid crystal device according to claim 8 as a light modulation device.

Images