JP2005227699A - Method for manufacturing micro-optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a micro-optical element that facilitates the acquisition of a desired shape with low cost. <P>SOLUTION: The method is characterized by including: a first shape forming step for forming a first shape 104, which is acquired by reducing a second shape 107 and substantially similar thereto, in a resist layer 103 on a substrate 101; and a shape extension step for extending the size of the first shape 104 to the extent to become the second shape 107. As the second shape 107, for example, an aspheric surface shape is given which has an inflection point. Consequently, the micro-optical element can be manufactured which has the aspheric surface of such a complicated shape, e.g., a microlens element. Also, the microlens element can be used, for example, for improving light use efficiency of a spatial light modulation apparatus such as a liquid crystal panel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a micro optical element, and more particularly to a method for manufacturing a micro optical element suitable for a spatial light modulator that modulates incident light according to an image signal.

  In a projector, it is necessary to improve the light use efficiency in order to obtain a bright projected image. For this reason, for example, a microlens array is used in a spatial light modulator provided in a projector, in particular, a liquid crystal spatial light modulator. The microlens array efficiently collects the illumination light from the light source unit on each pixel of the spatial light modulator. In recent years, in order to further improve the light utilization efficiency, the microlens elements constituting the microlens array are increasingly having complicated shapes such as aspheric surfaces. In order to manufacture a microlens element having a desired shape, a method of dry etching a substrate has been proposed (see, for example, Patent Document 1). A method of manufacturing a microlens element by wet etching the substrate is also conceivable.

Special Table 2000-530587

  In Patent Document 1, first, a desired aspheric shape is formed in a resist layer. Thereafter, the aspherical shape is transferred to the glass substrate using a dry etching method. The dry etching method has an advantage that a complicated shape can be formed. However, fine irregularities are generated on the surface of the finally obtained microlens element. Such a concavo-convex shape is a problem because it causes scattered light. Further, in the dry etching method, residues are accumulated in the chamber. In order to remove the residue, it is necessary to generate a plasma in an atmosphere such as oxygen or argon and then exhaust the plasma. For this reason, the cleaning of the residue is a problem because it requires a great running cost.

  In the method of obtaining a desired aspherical shape by the wet etching method, first, layers having different etching rates are formed on a glass substrate. Then, the opening is patterned on the surface and wet etching is performed. The wet etching method has an advantage that a microlens element can be manufactured at low cost. However, in the wet etching method, since there are few parameters (etching rate) that can be controlled, the degree of freedom of shapes that can be manufactured is small. For this reason, for example, it is a problem because it is difficult to accurately manufacture a complex aspheric shape having an inflection point.

  The present invention has been made in view of the above, and an object of the present invention is to provide a method of manufacturing a micro optical element that can easily obtain a desired shape at low cost.

  In order to solve the above-described problems and achieve the object, according to the present invention, a first shape forming step of reducing the second shape and forming a substantially similar first shape on the resist layer on the substrate; And a shape enlarging process for enlarging the size of the first shape until it reaches the second shape. In the present invention, first, a similar shape obtained by reducing the desired second shape is finally formed in the resist layer on the substrate. For this reason, the first shape formed first may be smaller than the second shape finally obtained. Therefore, even when the second shape is a complex aspherical shape having an inflection point, for example, the first shape can be easily formed in a small region. And a 1st shape is expanded to a 2nd shape by a shape expansion process. For this reason, even when the micro optical element has a complicated shape, a desired shape can be easily obtained at low cost.

  Moreover, according to a preferable aspect of the present invention, it is desirable that the shape enlarging step includes a dry etching step and a wet etching step. In the dry etching process, a shape having a ratio of about 1: 1 with the first shape can be formed. In the wet etching process, the shape obtained in the dry etching process is expanded to the final second shape. In the dry etching process, a minute uneven shape, for example, an uneven shape of several tens of nanometers is generated in the formed shape. In the wet etching process, such a minute uneven shape can be smoothed. For this reason, a micro optical element with a smooth surface and reduced scattered light can be obtained. Further, in the wet etching process, it is only necessary to immerse the substrate in the etchant. For this reason, a lot of micro optical elements can be manufactured at low cost.

  Further, according to a preferred aspect of the present invention, the method further includes a resist layer forming step of forming at least a resist layer on the substrate, and the dry etching step includes etching the resist layer in which the first shape is formed, It is desirable to form a shape substantially the same size as the first shape on the substrate, and in the wet etching step, the shape formed on the substrate is expanded to the second shape. A first shape is formed on the resist layer by, for example, a laser drawing method, an electron beam drawing method, a gray scale lithography method, an area gradation lithography method, or the like. In these methods, a desired complicated shape can be accurately formed. In addition, the first shape has a smaller area than the second shape. For this reason, even when these methods are used, the first shape can be formed in a short time. Thereby, even when the second shape is a complicated shape, the first shape can be created accurately and easily.

  Moreover, according to the preferable aspect of this invention, it is desirable to further include the resin filling process which fills the board | substrate with which the 2nd shape is formed with optically transparent resin. Thereby, a micro optical element that refracts light at the interface between the finally obtained second shape and the optical transparent resin can be easily obtained.

  In addition, according to a preferable aspect of the present invention, it is desirable to further include a mold transfer step of transferring the second shape to another member using the substrate on which the second shape is formed as a mold. Thereby, the other member in which the 2nd shape and the shape in which the unevenness | corrugation is reversed can be easily obtained using mold transfer.

  Embodiments of a method for manufacturing an optical element according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

  FIGS. 1-1 to 1-6 show the procedure of the method for manufacturing the micro optical element according to the first embodiment of the present invention. A case where an aspherical surface having an inflection point is manufactured as a micro optical element will be described. 1-1, a mask 102 serving as a protective film is formed on a substrate 101 made of quartz, glass, or the like by CVD (Chemical Vapor Deposition) or sputtering. The mask 102 is made of Cr or Si, such as poly-Si. Subsequently, a resist layer 103 is applied on the mask 102 in a resist layer forming step. As the resist layer 103, for example, AZ4620, AZP4902 (product name) manufactured by Clariant, or S900 (product name) manufactured by Shipley Company can be used.

  In the first shape forming step shown in FIG. 1-2, the second shape 107 (FIG. 1-5) that is finally desired is reduced and the first shape 104 that is substantially similar to the resist layer 103 on the substrate 101 is formed. Form. The first shape 104 formed first may be smaller than the second shape 107 finally obtained. Therefore, even when the second shape 107 is a complex aspherical shape having an inflection point, for example, the first shape 104 can be easily formed in a small region. The first shape 104 is formed on the resist layer 103 by, for example, laser drawing, electron beam drawing, gray scale lithography, area gradation lithography, or the like. Since the area of the first shape 104 is smaller than that of the second shape 107, the first shape 104 can be formed in a short time even when these methods are used. Thereby, even when the second shape 107 is a complicated shape, the first shape 104 can be created accurately and easily.

In the dry etching step shown in FIG. 1-3, the resist layer 103 on which the first shape 104 is formed is dry etched. Thereby, the first shape 104 and a shape 105 that is substantially the same size as the first shape 104 are formed on the substrate 101. For example, the RIE / ICP method is used for the dry etching. As the reaction gas, a mixed gas of Ar, C ₄ F ₈ and XeF ₂ is used. Ar acts on shape etching by physical atomic collision. C ₄ F ₈ acts on the reactive etching of the substrate 101 such as glass. XeF ₂ acts on the reactive etching of the mask 102 made of poly-Si. Such a mixed gas acts in the order of Ar, XeF ₂ and C ₄ F ₈ from the start of etching. The ratio of supplying each gas is preferably changed in the order of Ar, XeF ₂ and C ₄ F ₈ . For example, the RIE method is performed under the conditions shown in the following order of Step 1, Step 2, and Step 3.
(Step 1) 0.665 Pa, RF power 500 W, Ar: XeF ₂ : C ₄ F ₈ = 1: 1: 10, 2 minutes (Step 2) 2.5 Pa, RF power 500 W, Ar: XeF ₂ : C ₄ F ₈ = 1: 5: 10, 3 minutes (step 3) 6.5 Pa, RF power 1000 W, Ar: XeF ₂ : C ₄ F ₈ = 1: 0: 50, ₈ minutes

As a result, as shown in FIG. 1C, the first shape 104 formed in the resist layer 103 and a shape 105 that is substantially the same size as the first shape 104 can be formed on the substrate 101. Preferably, it is desirable to add more O ₂ to the mixed gas. Thereby, it can reduce that a residue adheres to the surface of the formed surface. In the dry etching process, an opening 102a of the mask 102 for a wet etching process described later is formed. In such a dry etching process, the processing time can be reduced as compared with the prior art.

  In the wet etching process shown in FIGS. 1-4, the shape 105 obtained in the dry etching process is expanded to the final second shape 107. The wet etching is performed by, for example, immersing the substrate 101 in a solution obtained by adding 30% ammonium fluoride solution to 5% hydrofluoric acid solution for 30 minutes. As a result, the substantially equal-sized shape 105 is etched approximately isotropically, and the shape is enlarged. Ammonium fluoride has a function of suppressing deterioration of the hydrofluoric acid etchant. Thereby, a uniform etching rate can be obtained. Further, it is desirable that the temperature in the etching tank is uniform within a range of 20 ° C ± 1 ° C. Thereby, the inside of the substrate 101 can be formed in a uniform shape by matching the etching rate within the surface to be etched.

  In the dry etching process, a minute uneven shape, for example, an uneven shape of several tens of nanometers, is generated on the processing surface due to the influence of reaction assist by plasma. The uneven shape on the processed surface generates scattered light on the lens surface. The light use efficiency is reduced by the scattered light. In the wet etching process, such minute irregularities can be smoothed. Therefore, it is possible to obtain a micro optical element having a smooth processed surface and reduced scattered light. More preferably, the smoothness of the processed surface can be further improved by adding 3% of a surfactant to the etchant. Further, in the wet etching process, it is only necessary to immerse the substrate in the etchant. For this reason, a lot of micro optical elements can be manufactured at low cost. In addition, even when the micro optical element has a complicated shape having an inflection point, the first shape 104 is simply enlarged, so that a desired shape can be easily obtained in large quantities at a low cost. The shape enlargement process is formed by the above-described dry etching process and wet etching process.

  In the resin filling step shown in FIGS. 1-6, the optically transparent resin 108 is filled into the substrate 101 on which the second shape 107 is formed. A micro optical element that refracts light at the interface between the second shape 107 and the optical transparent resin 108 can be easily obtained. This micro optical element has functions of high efficiency, high contrast, and high light resistance. Then, a TFT substrate or the like is formed on the optical transparent resin 108 using the manufactured micro optical element as a micro lens element. Thereby, a spatial light modulation device including a microlens array including a plurality of microlens elements can be configured. Details of such a spatial light modulator will be described later with reference to FIG.

  Further, the processed substrate 101 can be opposed to each other, and an optical transparent resin can be filled between the substrates 101. Thereby, a biconvex aspherical lens can be obtained.

  Further, instead of forming the microlens element on the processed substrate 101, a mold transfer step of transferring the second shape 107 to another member using the substrate 101 on which the second shape 107 is formed as a mold is further performed. May be included. As a result, it is possible to easily obtain another member having a shape in which the unevenness is reversed from that of the second shape 107 by using mold transfer.

  Next, such a mold transfer process will be described with reference to FIGS. 2-1 to 2-4. In FIG. 2A, the transfer member 151 as a precursor is preferably a low-viscosity liquid material. Such a substance can easily transfer the shape of the surface of the substrate 101 even at normal temperature, normal pressure, or in the vicinity thereof. The liquid substance is preferably a substance that can be cured by applying energy. When such a substance is used, it becomes easy to control the timing of solidifying the transfer member 151 to form the micro optical element 160, so that it is easy to improve productivity and accuracy, and a robust micro optical element 160 is obtained. easy.

  Further, a material having plasticity can be used as the transfer member 151 which is another member. Further, the transfer member 151 is not particularly limited as long as it has a strength capable of supporting the structure formed thereon after solidification, but a resin can be used. As the resin, one having energy curability or one having plasticity can be easily obtained, which is preferable.

  It is desirable that the resin having energy curability be curable by applying at least one of light and heat. The use of light and heat can use a general-purpose exposure apparatus, a heating apparatus such as a bake furnace or a hot plate, and can reduce equipment costs.

  As such resin having energy curability, for example, acrylic resin, epoxy resin, melamine resin, polyimide resin and the like can be used. In particular, an acrylic resin is suitable because it can be easily cured in a short time by irradiation with light by using various precursors and photosensitizers (photopolymerization initiators) on the market.

  Specific examples of the basic composition of the photocurable acrylic resin include prepolymers or oligomers, monomers, and photopolymerization initiators.

  Examples of the prepolymer or oligomer include epoxy acrylates, urethane acrylates, polyester acrylates, polyether acrylates, acrylates such as spiroacetal acrylates, epoxy methacrylates, urethane methacrylates, polyester methacrylates, and polyethers. Methacrylates such as methacrylates can be used.

  Examples of the monomer include 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, N-vinyl-2-pyrrolidone, carbitol acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, Monofunctional monomers such as dicyclopentenyl acrylate and 1,3-butanediol acrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, ethylene Bifunctional monomers such as glycol diacrylate, polyethylene glycol diacrylate, pentaerythritol diacrylate, and trimethylo Propane triacrylate, trimethylol propane trimethacrylate, pentaerythritol triacrylate, polyfunctional monomers such as dipentaerythritol hexaacrylate available.

  Examples of the photopolymerization initiator include acetophenones such as 2,2-dimethoxy-2-phenylacetophenone, butylphenones such as α-hydroxyisobutylphenone and p-isopropyl-α-hydroxyisobutylphenone, and p-tert-butyl. Halogenated acetophenones such as dichloroacetophenone, p-tert-butyltrichloroacetophenone, α, α-dichloro-4-phenoxyacetophenone, benzophenones such as benzophenone, N, N-tetraethyl-4,4-diaminobenzophenone, benzyl, benzyl Benzyls such as dimethyl ketal, benzoins such as benzoin and benzoin alkyl ether, oximes such as 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, 2-methyl Thioxanthone, 2-xanthones such as chlorothioxanthone, Michler's ketone, radical generating compounds such as benzyl methyl ketal are available.

  If necessary, a compound such as amines may be added for the purpose of preventing curing inhibition by oxygen, or a solvent component may be added for the purpose of facilitating coating. The solvent component is not particularly limited, and various organic solvents such as propylene glycol monomethyl ether acetate, methoxymethyl propionate, ethoxyethyl propionate, ethyl lactate, ethyl pyruvate, methyl amyl ketone, etc. Is available.

  The use of these substances is preferable because the release from the substrate 101 is good when the substrate 101 is formed of silicon or quartz.

  Moreover, as resin which has plasticity, resin which has thermoplasticity, such as a polycarbonate-type resin, a polymethylmethacrylate-type resin, an amorphous polyolefin-type resin, can be utilized, for example.

  Then, as shown in FIG. 2B, the above-described substrate 101 is prepared. The substrate 101 has a second shape 107 formed in the recess. The second shape 107 and the transfer member 151 are brought into close contact with each other. Alternatively, the transfer member 151 may be provided in the form of a lump in the substantially central portion of the second substrate 150, and the transfer member 151 may be spread out by the second substrate 150 and the substrate 101. By doing so, bubbles between the transfer member 151 and at least one of the second substrate 150 and the substrate 101 are released to the outside, and the bubbles are less likely to remain.

  Instead of placing the transfer member 151 on the substrate 10, it may be placed on the substrate 101 or on both the second substrate 150 and the substrate 101. In addition, the transfer member 151 may be preliminarily spread to a predetermined area on one or both of the second substrate 150 and the substrate 101. Further, if necessary, when the second substrate 150 and the substrate 101 are brought into close contact with each other via the transfer member 151, the transfer member 151 may be pressurized via at least one of the second substrate 150 and the substrate 101. good. By pressurizing, the time during which the transfer member 151 spreads and spreads to a predetermined area can be shortened, so that workability is improved and filling between the second shapes 107 which are the concave portions of the substrate 101 is ensured.

  By bringing the substrate 101 and the second substrate 150 into close contact with each other via the transfer member 151, the shape corresponding to the surface having the second shape 107 which is the concave portion of the substrate 101 is transferred to the transfer member 151. That is, the transfer member 151 is formed with the micro optical element 160 that is the inverted shape of a plurality of recesses and the flat surface 153 that corresponds to the flat surface 152 that is formed around the second shape 107 that is a recess. .

  Subsequently, as shown in FIG. 2-2, the transfer member 151 is solidified. For example, when the transfer member 151 includes a photocurable material, the transfer member 151 is irradiated with light 155. In that case, the substrate 101 preferably has a light-transmitting property, and light 155 can be irradiated through the substrate 101. Alternatively, when a plasticized resin heated to a temperature higher than the softening point is used as the transfer member 151, it can be solidified by cooling.

Next, as shown in FIG. 2-3, the substrate 101 is peeled from the micro optical element 160. Here, a procedure for improving the releasability when the substrate 101 is peeled will be described. A low adhesion layer is formed on the surface of the micro optical element 160. The low adhesion layer is formed of a material that repels the transfer member 151. For example, if the transfer member 151 is hydrophilic, the low adhesion layer is formed of a hydrophobic material such as silicon. If the transfer member 151 is hydrophobic, a low adhesion layer is formed of a hydrophilic material such as metal or SiO ₂ . Alternatively, if the low adhesion layer is formed by coating with fluorine (a compound having an atom (F)), the transfer member 151 repels whether it is hydrophilic or hydrophobic. For example, when the substrate 101 is formed of a silicon-based material, fluorine coating can be performed by performing surface treatment with a silane coupling agent having fluorine atoms. Also, as shown in FIG. 2-4, the substrate 101 is left in an atmosphere 161 of HMDS (a product name of positive resist adhesion assistant manufactured by Clariant Japan) for 30 minutes or more. Thereafter, mold releasability is improved by performing mold transfer.

  3A to 3C illustrate the procedure of the method for manufacturing the micro optical element according to the second embodiment. In the present embodiment, a procedure for forming an aspheric surface having no inflection point is shown. This embodiment differs from the first embodiment in that no mask is used. First, in a resist layer forming step, a resist layer 113 is formed on a substrate 111 made of quartz or glass. Then, as illustrated in FIG. 3A, a first shape 114 that is reduced in size approximately similar to a desired aspheric shape is formed in the resist layer 113 by a gray scale lithography method. As the gray scale lithography method, an area gradation mask or a gray scale mask using photosensitive glass can be used.

In the dry etching process shown in FIG. 3B, the first shape 114 and the shape 115 having the same size as the first shape 114 are transferred to the substrate 111 by RIE using C ₄ F ₈ or SF ₆ which is a hydrofluoric acid gas. As described in the first embodiment, the shape 115 has an uneven shape on the processed surface due to the influence of the dry etching process.

  In the wet etching step shown in FIG. 3-3, the substrate 111 is swung by being immersed in a hydrofluoric acid solution (HF 3%) and a surfactant 5% solution bath for 3 minutes. Thereby, the shape 115 can be enlarged and the second shape 117 can be obtained. Also, the uneven shape is smoothed. In this embodiment, in order to form an aspherical surface having no inflection point, it is only necessary to perform isotropic etching in the process from the dry etching process to the wet etching process. Therefore, unlike the first embodiment, no mask is required.

(Spatial light modulator)
Next, a liquid crystal panel 520R which is a spatial light modulation device including the microlens element 203 which is a micro optical element obtained by the above embodiment will be described with reference to FIG. The liquid crystal panel 520R modulates and emits incident light according to the image signal. The liquid crystal panel 520R is arranged in a lattice shape in which a plurality of opening areas AP are substantially orthogonal. The opening area AP which is a pixel opening is a rectangular opening formed in the black matrix 205 having a light shielding function. The opening area AP corresponds to one pixel. FIG. 4 shows only a portion of one opening area AP among the plurality of opening areas AP of the liquid crystal panel 520R. The configuration of the liquid crystal panel 520R corresponding to the other opening regions is the same as the configuration shown in FIG. Red light (hereinafter referred to as “R light”) from an ultra high pressure mercury lamp (not shown) enters the liquid crystal panel 520R from the left side of FIG. 4, and exits from the right side toward the screen (not shown). Inside the incident-side dustproof transparent plate 201 (exit side), a microlens element 203 that is a lens portion is formed by a microlens array substrate 202 and an optically transparent adhesive layer 204. The detailed configuration and operation of the microlens element 203 will be described later. One microlens element 203 is provided corresponding to one corresponding opening area AP. Looking at the entire liquid crystal panel 520R, a plurality of microlens elements 203 are arranged on a plane corresponding to the plurality of aperture regions AP to form a microlens array that is a refractive optical unit.

  A counter substrate 206 having a transparent electrode 207 made of an ITO film or the like is formed on the inner side (outgoing side) of the microlens element 203. Further, a black matrix 205 serving as a light shielding portion is formed between the counter substrate 206 and the transparent electrode 207. As described above, the black matrix 205 is provided with the rectangular opening area AP corresponding to the pixel. Furthermore, an alignment film 208 that has been subjected to a predetermined alignment process such as a rubbing process is provided on the emission side of the transparent electrode 207. The alignment film 208 is made of, for example, a transparent organic film such as a polyimide film.

  A TFT substrate 212 is formed on the inner side (incident side) of the emission-side dust-proof transparent plate 213. Inside the TFT substrate 212, a transparent electrode and a TFT (thin film transistor) forming layer 211 are provided. An alignment film 210 is provided further inside (incident side) of the TFT formation layer 211. The rubbing direction of the alignment film 208 and the rubbing direction of the alignment film 210 are arranged so as to be substantially orthogonal. Then, the incident side dustproof transparent plate 201 and the emission side dustproof transparent plate 213 are bonded together with the counter substrate 206 and the TFT substrate 212 facing each other. A liquid crystal layer 209 for image display is sealed between the counter substrate 206 and the TFT substrate 212.

  Here, the optically transparent microlens array substrate 202 manufactured according to the above-described embodiment and the optically transparent adhesive layer 204 constitute a microlens element 203 that is a lens portion. Incident light that is a substantially parallel light beam is refracted at the interface between the microlens array substrate 202 and the adhesive layer 204. The microlens element is composed of, for example, an aspherical sub-lens that is divided into four with respect to the square opening area AP. Each aspheric lens has a shape having an inflection point. At this time, each of the four aspherical sub-lenses is designed by controlling the focal position for each annular zone. When the four aspherical sub-lenses are arranged, a synthetic annular zone that is synthesized around the optical axis AX is formed. Hereinafter, the synthesized synthetic ring-shaped part is simply referred to as a substantially ring-shaped part or a ring-shaped part.

  Each of the four aspherical sub-lenses is designed such that the annular portion has an optimized focal position. Then, the microlens element 203 obtained by synthesizing the four aspherical sub-lenses functions as one aspherical lens having a plurality of focal positions different for each of the plurality of substantially annular portions R1 and R2 centered on the optical axis AX. . By processing such an aspherical surface, for example, illumination light from an ultra-high pressure mercury lamp can efficiently pass through the opening area AP, and the amount of light emitted from the opening area AP can be reduced. As a result, light can be used with high efficiency. Furthermore, the light distribution density can be made substantially uniform in the vicinity of the liquid crystal layer 209. As a result, local concentration of light energy in the vicinity of the liquid crystal layer 209 can be reduced, so that deterioration of the alignment films 208 and 210 can be reduced. Therefore, a long-life liquid crystal panel 520R can be obtained.

  According to the above-described embodiment, even the microlens element 203 having such a complicated shape can be manufactured accurately and easily. The spatial light modulation device including the microlens element 203 can realize high efficiency, high contrast, and high light resistance.

(projector)
Next, a schematic configuration of a projector including the liquid crystal panel 520R that is the above-described spatial light modulation device will be described. In FIG. 5, an ultra-high pressure mercury lamp 501 that is a light source unit includes R light that is first color light, green light that is second color light (hereinafter referred to as “G light”), and blue light that is third color light ( Hereinafter, light including “B light”) is supplied. The integrator 504 makes the illuminance distribution of the light from the extra-high pressure mercury lamp 501 uniform. The light whose illuminance distribution is made uniform is converted into polarized light having a specific vibration direction, for example, s-polarized light by the polarization conversion element 505. The light converted into the s-polarized light is incident on the R light transmitting dichroic mirror 506R that constitutes the color separation optical system. Hereinafter, the R light will be described. The R light transmitting dichroic mirror 506R transmits R light and reflects G light and B light. The R light transmitted through the R light transmitting dichroic mirror 506R is incident on the reflection mirror 507. The reflection mirror 507 bends the optical path of the R light by 90 degrees. The R light whose optical path is bent is incident on a first color light spatial light modulator 510R that modulates the R light, which is the first color light, in accordance with the image signal. The spatial light modulator for first color light 510R is a transmissive liquid crystal display device that modulates R light according to an image signal. Since the polarization direction of the light does not change even if it passes through the dichroic mirror, the R light incident on the first color light spatial light modulator 510R remains as s-polarized light.

  The spatial light modulator for first color light 510R includes a λ / 2 phase difference plate 523R, a glass plate 524R, a first polarizing plate 521R, a liquid crystal panel 520R, and a second polarizing plate 522R. The detailed configuration of the liquid crystal panel 520R will be described later. The λ / 2 phase difference plate 523R and the first polarizing plate 521R are disposed in contact with a light-transmitting glass plate 524R that does not change the polarization direction. Thereby, the problem that the first polarizing plate 521R and the λ / 2 phase difference plate 523R are distorted by heat generation can be avoided. In FIG. 5, the second polarizing plate 522 </ b> R is provided independently, but may be disposed in contact with the exit surface of the liquid crystal panel 520 </ b> R or the entrance surface of the cross dichroic prism 512.

  The s-polarized light incident on the first color light spatial light modulator 510R is converted into p-polarized light by the λ / 2 phase difference plate 523R. The R light converted into p-polarized light passes through the glass plate 524R and the first polarizing plate 521R as it is and enters the liquid crystal panel 520R. The p-polarized light incident on the liquid crystal panel 520R is converted into s-polarized light by modulation according to the image signal. The R light converted into s-polarized light by the modulation of the liquid crystal panel 520R is emitted from the second polarizing plate 522R. In this way, the R light modulated by the first color light spatial light modulator 510R is incident on the cross dichroic prism 512, which is a color synthesis optical system.

  Next, the G light will be described. The G light and B light reflected by the R light transmitting dichroic mirror 506R have their optical paths bent 90 degrees. The G light and the B light whose optical paths are bent enter the B light transmitting dichroic mirror 506G. The B light transmitting dichroic mirror 506G reflects G light and transmits B light. The G light reflected by the B light transmitting dichroic mirror 506G is incident on the second color light spatial light modulator 510G that modulates the G light as the second color light according to the image signal. The spatial light modulator for second color light 510G is a transmissive liquid crystal display device that modulates G light according to an image signal. The second color light spatial light modulator 510G includes a liquid crystal panel 520G, a first polarizing plate 521G, and a second polarizing plate 522G. Details of the liquid crystal panel 520G will be described later.

  The G light incident on the second color light spatial light modulator 510G is converted into s-polarized light. The s-polarized light incident on the second color light spatial light modulator 510G passes through the first polarizing plate 521G as it is and enters the liquid crystal panel 520G. The s-polarized light incident on the liquid crystal panel 520G is converted into p-polarized light by modulation according to the image signal. The G light converted into the p-polarized light by the modulation of the liquid crystal panel 520G is emitted from the second polarizing plate 522G. In this way, the G light modulated by the second color light spatial light modulator 510G is incident on the cross dichroic prism 512, which is a color synthesis optical system.

  Next, the B light will be described. The B light transmitted through the B light transmitting dichroic mirror 506G passes through the two relay lenses 508 and the two reflection mirrors 507, and modulates the B light as the third color light in accordance with the image signal. It enters the spatial light modulator for color light 510B. The spatial light modulator for third color light 510B is a transmissive liquid crystal display device that modulates B light according to an image signal.

  The reason why the B light passes through the relay lens 508 is that the optical path length of the B light is longer than the optical path lengths of the R light and the G light. By using the relay lens 508, the B light transmitted through the B light transmitting dichroic mirror 506G can be directly guided to the third color light spatial light modulator 510B. The spatial light modulator for third color light 510B includes a λ / 2 phase difference plate 523B, a glass plate 524B, a first polarizing plate 521B, a liquid crystal panel 520B, and a second polarizing plate 522B. The configuration of the spatial light modulator for third color light 510B is the same as the configuration of the spatial light modulator for first color light 510R described above, and thus detailed description thereof is omitted.

  The B light incident on the third color light spatial light modulator 510B is converted into s-polarized light. The s-polarized light incident on the third color light spatial light modulator 510B is converted into p-polarized light by the λ / 2 phase difference plate 523B. The B light converted into p-polarized light passes through the glass plate 524B and the first polarizing plate 521B as it is, and enters the liquid crystal panel 520B. The p-polarized light incident on the liquid crystal panel 520B is converted into s-polarized light by modulation according to the image signal. The B light converted into the s-polarized light by the modulation of the liquid crystal panel 520B is emitted from the second polarizing plate 522B. The B light modulated by the spatial light modulator for third color light 510B is incident on a cross dichroic prism 512 that is a color synthesis optical system. As described above, the R light transmissive dichroic mirror 506R and the B light transmissive dichroic mirror 506G constituting the color separation optical system convert the light supplied from the ultrahigh pressure mercury lamp 501 into the R light that is the first color light and the second light. The light is separated into G light, which is colored light, and B light, which is third color light.

  The cross dichroic prism 512, which is a color synthesis optical system, is configured by arranging two dichroic films 512a and 512b orthogonally in an X shape. The dichroic film 512a reflects B light and transmits R light and G light. The dichroic film 512b reflects R light and transmits B light and G light. As described above, the cross dichroic prism 512 includes the R light and G light modulated by the first color light spatial light modulation device 510R, the second color light spatial light modulation device 510G, and the third color light spatial light modulation device 510B, respectively. And B light. The projection lens 514 projects the light combined by the cross dichroic prism 512 onto the screen 516. Thereby, a full color image can be obtained on the screen 516.

  As described above, the light incident on the cross dichroic prism 512 from the first color light spatial light modulator 510R and the third color light spatial light modulator 510B is set to be s-polarized light. The light incident on the cross dichroic prism 512 from the second color light spatial light modulator 510G is set to be p-polarized light. In this way, by changing the polarization direction of the light incident on the cross dichroic prism 512, the light emitted from the spatial light modulators for the respective color lights in the cross dichroic prism 512 can be effectively combined. The dichroic films 512a and 512b are usually excellent in the reflection characteristics of s-polarized light. For this reason, R light and B light reflected by the dichroic films 512a and 512b are s-polarized light, and G light transmitted through the dichroic films 512a and 512b is p-polarized light.

  The project 500 includes spatial light modulators 510R, 510G, and 510B each including a microlens element 203 having a desired shape manufactured according to the above-described embodiment. Therefore, the projector 500 is inexpensive and can realize high efficiency, high contrast, and high light resistance.

FIG. 3 is a diagram illustrating a method for manufacturing the micro optical element according to the first embodiment. FIG. 5 is another view for explaining the method of manufacturing the micro optical element according to the first embodiment. FIG. 6 is still another view for explaining the method of manufacturing the micro optical element according to the first embodiment. FIG. 4 is another diagram for explaining a method of manufacturing the micro optical element according to the first embodiment. FIG. 6 is still another diagram illustrating a method for manufacturing the micro optical element according to the first embodiment. FIG. 3 is a diagram illustrating a method for manufacturing the micro optical element according to the first embodiment. The figure explaining type | mold transcription | transfer. FIG. 4 is another diagram illustrating mold transfer. FIG. 6 is still another diagram illustrating mold transfer. FIG. 6 is another diagram illustrating mold transfer. FIG. 6 is a diagram illustrating a method for manufacturing the micro optical element according to the second embodiment. FIG. 10 is another view for explaining the method of manufacturing the micro optical element according to the second embodiment. FIG. 6 is still another view for explaining the method of manufacturing the micro optical element according to the second embodiment. The schematic block diagram of a spatial light modulation apparatus provided with a micro optical element. The schematic block diagram of a projector provided with a spatial light modulation device.

Explanation of symbols

  101 substrate, 102 mask, 102a opening, 103 resist layer, 104 first shape, 105 substantially equal shape, 107 second shape, 108 optically transparent resin, 111 substrate, 113 resist layer, 114 first Shape, 115 substantially equal size, 117 second shape, 520R liquid crystal panel, 150 second substrate, 151 transfer member, 152 flat surface, 153 flat surface, 155 light, 160 micro optical element, 161 atmosphere, 201 incident side Dust-proof transparent plate, 202 microlens array substrate, 203 microlens element, 204 adhesive layer, 205 black matrix, 206 counter substrate, 207 transparent electrode, 208 alignment film, 209 liquid crystal layer, 210 alignment film, 211 formation layer, 212 substrate 213 Dust-proof transparent plate on the exit side, 501 super high Mercury lamp, 504 integrator, 505 polarization conversion element, 506R R light transmission dichroic mirror, 506G G light transmission dichroic mirror, 507 reflection mirror, 508 relay lens, 510R, 510G, 510B spatial light modulator for each color light, 512 cross dichroic prism 512a dichroic film, 512b dichroic film, 514 projection lens, 516 screen, 520R, 520G, 520B liquid crystal panel, 521R, 521G, 521B first polarizing plate, 522R, 522G, 522B second polarizing plate, 523R, 523B retardation plate 524R, 524B Glass plate, AX Optical axis

Claims (5)

A first shape forming step of reducing the second shape and forming a substantially similar first shape on the resist layer on the substrate;
And a shape enlarging step of enlarging the size of the first shape to the second shape.   The method for manufacturing a micro optical element according to claim 1, wherein the shape enlarging step includes a dry etching step and a wet etching step. A resist layer forming step of forming at least a resist layer on the substrate;
The dry etching step forms a shape having a size substantially the same as the first shape on the substrate by etching the resist layer on which the first shape is formed,
3. The method of manufacturing a micro optical element according to claim 1, wherein the wet etching step expands the shape formed on the substrate until the second shape is reached.   The method of manufacturing a micro optical element according to claim 1, further comprising a resin filling step of filling the substrate on which the second shape is formed with an optical transparent resin. .   4. The method according to claim 1, further comprising a mold transfer step of transferring the second shape to another member using the substrate on which the second shape is formed as a mold. 5. The manufacturing method of the micro optical element of description.

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