JP2009210714A - Mirror unit and rear projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mirror unit for a rear projector or the like, which can surely prevent the sticking of dust without requiring a special operation with a simple configuration. <P>SOLUTION: The sticking of water and oil to a surface 30S is suppressed by a water- and oil-repellent film 30 provided on the reflecting surface 20S of a base material 20. The base material 20 is made of metal, thereby reducing a surface resistance on the surface 30S. Thus, the sticking of foreign matter to the surface of the mirror unit 18 such as the surface 30S can be prevented without the special operation. Further, when the dust is stuck, the stuck dust can easily be removed by a blower, etc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mirror unit for a rear projector and a rear projector.

  In the rear projector, the projection light emitted from the optical unit is reflected toward the screen by the reflection mirror. When the fan for cooling the optical unit operates, dust or the like enters from the outside of the rear projector casing. And the method of preventing the image quality fall of a projection image produced by adhesion to the reflective mirrors of the dust etc. which penetrate | invaded is known (for example, refer patent document 1 and 2).

Such a method includes providing a cleaning unit for cleaning the reflecting surface of the reflecting mirror and keeping the reflecting surface clean by moving the cleaning unit along the reflecting mirror (for example, Patent Document 1). There is also known a method of decomposing the attached organic dust by coating a reflective surface of a reflecting mirror with a titanium oxide film (for example, Patent Document 2).
JP 2005-257800 A Japanese Patent Laid-Open No. 10-68998

  If a cleaning unit and a moving mechanism for moving the cleaning unit are provided to clean the reflecting surface of the reflecting mirror, the cleaning device becomes large. For this reason, it cannot be employed in a small rear projector. Further, according to this method, the reflective surface cannot be cleaned while the rear projector is in use, that is, when the projection light is emitted. This is because the cleaning device is projected onto the projected image on the screen when cleaning is performed.

  Moreover, the object of decomposition by the titanium oxide film is limited to organic matter. For this reason, it is not possible to remove all kinds of dust and the like attached to the reflecting surface, and dirt on the reflecting surface is gradually accumulated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a rear projector mirror unit or the like that can reliably prevent dust from adhering to a simple configuration without requiring a special operation.

  A first mirror unit of the present invention is a mirror unit of a rear projector that guides projection light emitted from an optical unit to a screen, and is formed on a base material having a reflection surface that reflects the projection light, and the reflection surface. And a water / oil repellent film formed on the binder film.

  The substrate is preferably a metal. The water / oil repellent film is preferably provided on the outermost side of the laminate including the water / oil repellent film. The water / oil repellent film includes, for example, a fluorine-containing organic polymer. The physical film thickness of the water / oil repellent film is preferably 0.4 to 100 nm.

  The binder film is made of, for example, silicon oxide. The physical film thickness of the binder film is preferably 5 to 500 nm. The binder film is preferably a dense film.

The surface resistance of the mirror unit is preferably 1 × 10 ¹⁴ Ω / □ or less.

  A second mirror unit of the present invention is a mirror unit of a rear projector that guides projection light emitted from an optical unit to a screen, and forms a base material and a reflective surface for reflecting the projection light. It is characterized by comprising a reflective film formed on the surface, a binder film formed on the reflective film, and a water / oil repellent film formed on the binder film.

  The substrate is, for example, glass or resin. The reflective film is preferably a dielectric.

  A first rear projector according to the present invention is a rear projector including an optical unit that emits projection light and a mirror unit that guides the projection light to a screen. The mirror unit emits projection light emitted from the optical unit. It is characterized by comprising a base material having a reflective surface for reflection, a binder film formed on the reflective surface, and a water / oil repellent film formed on the binder film.

  A second rear projector according to the present invention is a rear projector including an optical unit that emits projection light and a mirror unit that guides the projection light to a screen. The mirror unit is emitted from a base material and the optical unit. A reflective film formed on the surface of the base material to form a reflective surface for reflecting the projected light, a binder film formed on the reflective film, and a water / oil repellency formed on the binder film And a membrane.

  ADVANTAGE OF THE INVENTION According to this invention, the mirror unit for rear projectors etc. which can prevent adhesion of dust reliably by simple structure, without requiring special operation can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a rear projector provided with a mirror unit in the first embodiment.

  The rear projector 10 includes an optical unit 12, a screen 16, and a mirror unit 18. The optical unit 12 emits projection light. The projection light emitted from the optical unit 12 is reflected by the mirror unit 18 and guided to the screen 16 as indicated by an arrow. The screen 16 is disposed along the front surface 10F of the rear projector 10. The mirror unit 18 is disposed along the rear surface 10R of the rear projector 10 so as to reflect the projection light toward the screen 16 at a predetermined angle.

  FIG. 2 is an enlarged cross-sectional view of the mirror unit 18 in the present embodiment.

  The mirror unit 18 includes a base material 20 and a laminate 24. The base material 20 is provided to reflect the projection light. The laminate 24 prevents dust from adhering to the base material 20 and facilitates removal of dust when adhering.

  In the present embodiment, the base 20 of the mirror unit 18 is formed of a metal such as aluminum, titanium, copper, or iron. That is, unlike a general-purpose mirror using glass, resin, or the like, the projection light is reflected by the metal reflecting surface 20S. When a metal, particularly preferably aluminum, is used as the substrate 20, it is easy to process it into a complicated shape, such as an aspherical surface, as compared with the case of using glass. Further, the metal base 20 can improve the dustproof performance of the mirror unit 18 as will be described later.

  The laminate 24 includes a water / oil repellent film 30. The water / oil repellent film 30 is provided on the outermost surface of the mirror unit 18, that is, the surface opposite to the substrate 20. The water / oil repellent film 30 suppresses water and oil from adhering to the surface 30S. As a result, the adhesion of dust particles to the surface 30S can be prevented as follows.

When the liquid bridging force F ₁ represented by the following formula (1) acts between the base material 20 and the spherical dust particles, the dust particles are likely to adhere to the reflecting surface 20S of the base material 20.
F ₁ = −2πγD (1) (γ is the surface tension of the liquid, and D is the particle size of the dust particles)
Thus, the liquid cross-linking force F ₁ is a force generated by liquid cross-linking when the liquid aggregates at the contact portion between the base material 20 and the dust particles. Therefore, when the reflective surface 20S of the base material 20 is covered with the water / oil repellent film 30 and the adhesion of water or oil to the surface 30S of the water / oil repellent film 30 is suppressed, the adhesion of dust particles due to the liquid cross-linking force F ₁ is prevented. Can be reduced.

  The water / oil repellent film 30 is, for example, an organic silicon polymer containing fluorine, an organic or inorganic compound containing fluorine, an organic-inorganic hybrid polymer, a fluorinated pitch (for example, CFn (n: 1.1 to 1.6). )), Graphite fluoride or the like. This is because the water / oil repellent film 30 containing at least one of these fluorine compounds is excellent in water repellency and oil repellency.

Examples of the organosilicon polymer include a polymer obtained by hydrolyzing a fluorine-containing silane compound having a fluorocarbon group. As the fluorine-containing silane compound, CF ₃ (CF ₂ ) a (CH ₂ ) ₂ SiRbXc (2) (wherein R is an alkyl group, X is an alkoxy group or a halogen atom, a is an integer of 0 to 7, and b is an integer of 0 to 2) And c is an integer of 1 to 3, and b + c = 3).

As specific examples of the compound represented by the formula (2), CF ₃ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ , CF ₃ (CH ₂ ) ₂ SiCl ₃ , CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₅ (CH ₂ ) ₂ SiCl ₃ , CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ , CF ₃ (CF ₂ ) ₇ (CH _{2) 2 SiCl 3, CF 3} (CF 2) 7 (CH 2) 3 SiCH 3 (OCH 3) 2, CF 3 (CF 2) 7 (CH 2) 2 SiCH 3 Cl 2 , and the like. A commercially available product may be used as the organosilicon polymer. For example, XC98-B2472 (manufactured by GE Toshiba Silicone Co., Ltd.) can be used.

  Examples of the fluorine-containing organic compound include a fluororesin. Examples of the fluororesin include a polymer of a fluorine-containing olefin compound, and a copolymer comprising a fluorine-containing olefin compound and a monomer copolymerizable therewith. Examples of such (co) polymers include polytetrafluoroethylene, tetraethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, ethylene-chlorotri Examples include fluoroethylene copolymers, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymers, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride. A polymer obtained by polymerizing a commercially available fluorine-containing composition may be used as the fluororesin. As a commercially available fluorine-containing composition, for example, OPSTAR (manufactured by JSR Corporation), Cytop (registered trademark, manufactured by Asahi Glass Co., Ltd.) and the like can be mentioned.

Examples of the fluorine-containing inorganic compound include LiF, MgF ₂ , CaF ₂ , AlF ₃ , BaF ₂ , YF ₃ , LaF _3, and CaF ₃ . These fluorine-containing inorganic compounds can be obtained from Canon Optron, for example.

  Examples of the organic-inorganic hybrid polymer containing fluorine include a copolymer of a fluoroaliphatic group-containing unsaturated ester monomer and an unsaturated silane monomer, and an organosilicon polymer having a fluorocarbon group.

  The physical film thickness of the water / oil repellent film 30 is preferably 0.4 to 100 nm, and more preferably 10 to 80 nm. If the physical film thickness of the water / oil repellent film 30 is within a range of 0.4 to 100 nm, necessary light can be sufficiently transmitted while maintaining dust resistance. On the other hand, if the physical film thickness of the water / oil repellent film 30 is less than 0.4 nm, the water / oil repellency becomes insufficient, and if it exceeds 100 nm, the light transmittance is insufficient. There is a possibility that the surface resistance on the surface 30S of the water / oil repellent film 30 is increased and the dustproof performance is lowered.

  The stacked body 24 includes a binder film 32. The binder film 32 is formed on the reflective surface 20 </ b> S of the substrate 20, and the water / oil repellent film 30 is formed on the binder film 32. The binder film 32 is used to improve the adhesion between the water / oil repellent film 30 and the substrate 20. The binder film 32 is made of, for example, silicon oxide.

  The physical film thickness of the binder film 32 is preferably 5 to 500 nm, and more preferably 10 to 400 nm. This is because if the physical film thickness of the binder film 32 is less than 5 nm, the adhesion is not sufficiently improved, and the strength of the water / oil repellent film 30 can be lowered. On the other hand, if it is thicker than 500 nm, the strength of the binder film 32 is lowered due to compressive stress, which may adversely affect the optical characteristics, and the surface resistance on the surface 30S of the water / oil repellent film 30 is large as will be described later. This is because the dustproof performance may be reduced.

  Since the substrate 20 is made of metal, static electricity is not accumulated on the reflective surface 20S. For this reason, when the reflective surface 20S is exposed, it is possible to prevent dust from adhering to the reflective surface 20S due to static electricity. This is one of the advantages of making the base material 20 metal.

In the present embodiment, since the laminated body 24 having lower conductivity than the metal is provided on the reflecting surface 20S, it is preferable to suppress the surface resistance on the surface of the laminated body 24, that is, the surface 30S of the water / oil repellent film 30. Therefore, in the present embodiment, the surface resistance on the surface 30S is suppressed to 1 × 10 ¹⁴ Ω / □ or less by adjusting the material and thickness of the water / oil repellent film 30 and the binder film 32.

As a result, the dust is prevented from adhering to the mirror unit 18 due to static electricity, and the dustproof performance is improved. The surface resistance on the surface 30S is more preferably 1 × 10 ¹² Ω / □ or less.

  Mirror unit 18 includes a ground wire (not shown) that connects laminated body 24 and the housing of rear projector 10 (see FIG. 1). The ground wire is provided to discharge the electric charge accumulated in the laminate 24, that is, static electricity, to the casing of the rear projector 10. For this reason, it is prevented that the surface resistance on the surface 30S increases due to the electric charge accumulated in the laminate 24 after long-term use, and the dustproof performance of the surface 30S is kept good.

  Hereinafter, the manufacturing method of the member which comprises the mirror unit 18 of this embodiment is demonstrated. The base material 20 is molded while maintaining its gloss by grinding and polishing the surface. In the grinding process, a cutting method using a commonly used cutting machine can be used. As the cutting machine, for example, a surface grinder, a mirror grinder, a crank grinder, a lathe, a milling machine or the like is used. Also in the polishing step, a commonly used polishing process can be adopted. As a polishing method, for example, buffing, mirror polishing, wet polishing, lapping, electrolytic polishing, or the like is used.

  In the case of using a fluorine-containing inorganic compound as a material, the water / oil repellent film 30 is formed by a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method or an ion plating method, a chemical vapor deposition method such as thermal CVD or plasma CVD, or the like. . In addition, when a fluorine-containing organic compound and a fluorine-containing organic-inorganic hybrid polymer are used as materials, it can be formed by a coating method such as a dip coating method, a spin coating method, a spray method, a roll coating method, or a screen printing method. it can. In the case of forming by a coating method, it is preferable to remove the solvent by drying after coating for the purpose of increasing the strength of the resulting film. As a drying method, a commonly used method such as air drying, hot air drying, or heat drying can be used. What is necessary is just to select the drying conditions in the apply | coating method suitably according to the heat resistance etc. of a base material.

  The binder film 32 can be formed by a method similar to that used when the water / oil repellent film 30 is formed of a fluorine-containing inorganic compound (see paragraph [0037]). The binder film 32 is preferably a dense film rather than a porous film or the like from the viewpoint of the adhesive strength between the water / oil repellent film 30 and the substrate 20.

  In FIG. 2, the members constituting the laminate 24 are shown enlarged in the thickness direction, that is, the direction perpendicular to the reflecting surface 20 </ b> S of the base material 20 for convenience of explanation. The same applies to FIG. 3 described later.

  As described above, according to the present embodiment, in the mirror unit 18 having a simple structure in which the laminated body 24 including the water / oil repellent film 30 is formed on the reflective surface 20S of the metal base material 20, a special operation is performed. It is possible to prevent the dust from adhering without needing to be used. Since the water / oil repellent film 30 has water repellency and oil repellency, it is possible to prevent the adhesion of foreign substances widely regardless of the type of dust such as organic or inorganic materials. Furthermore, when dust adheres to the surface of the mirror unit 18 such as the surface 30S, the attached dust can be easily removed by a blower or the like.

  Further, in the present embodiment, since the dustproof performance can be improved by a simple process of forming the laminated body 24, the laminated body 24 is formed on the existing mirror unit to which the dust easily adheres, and the dust is attached. It is also possible to prevent this easily. And by forming the laminated body 24 with a member excellent in light transmittance, it is possible to realize the mirror unit 18 having a higher reflection efficiency than the case of using a photocatalyst that absorbs part of the projection light.

  In the present embodiment, a fine uneven film (not shown) for forming fine unevenness on the surface 30 </ b> S may be further laminated below the water / oil repellent film 30. When irregularities are formed on the surface 30S, the distance between the dust particles and the surface 30S is maintained, and the intermolecular force between the two becomes small. As a result, dust particles can be prevented from adhering to the surface 40S. Such a fine uneven film is preferably disposed immediately below the water / oil repellent film 30 in order to effectively form unevenness on the surface 30S. However, the binder film 32 may also be provided between the water / oil repellent film 30 and the fine uneven film to improve the adhesion between these film members.

  In such a fine concavo-convex film, it is preferable that fine concave portions and convex portions are randomly arranged. This is because the projection light emitted from the optical unit 12 is not attenuated if the concave portions and the convex portions are randomly arranged, so that the amount of reflected light guided to the screen 16 does not decrease.

  The surface roughness of the fine uneven film is adjusted such that the three-dimensional average surface roughness SRa on the surface 30S is 1 to 100 nm, preferably 8 to 80 nm, more preferably 10 to 50 nm. This is because if SRa on the surface 30S is 1 nm or more, dust particles can be sufficiently prevented from adhering to the surface 30S due to intermolecular force, whereas if it exceeds 100 nm, scattering of light incident on the laminate 24 is scattered. This is because it may occur.

  The fine uneven film is preferably formed of silicon oxide, alumina, aluminum hydroxide, zinc oxide, zinc hydroxide, or the like, and particularly preferably formed of silicon oxide (silica). This is because the fine concavo-convex film of silicon oxide has good adhesion to the water / oil repellency film 30, and therefore the binder film 32 between the water / oil repellency film 30 and the fine concavo-convex film (see paragraph [0042]). ) Is not necessary.

  Next, the second embodiment will be described with a focus on differences from the first embodiment. FIG. 3 is an enlarged sectional view showing the mirror unit 18 in the present embodiment.

  In the mirror unit 18 of the present embodiment, glass or resin is used as the base material 20. For this reason, the reflective film 36 which is a member for forming a reflection surface that reflects the projection light is provided on the surface 20 </ b> A of the base material 20 as a part of the laminate 24. That is, in the present embodiment, unlike the first embodiment, the projection light is reflected by the reflecting surface 36S.

  The reflective film 36 is a metal film, a metal oxide film, a cold mirror, or the like. As the metal film, silver, gold, platinum, aluminum or the like is used. As the metal oxide film, chromium oxide, silicon oxide, titanium oxide, aluminum oxide, or the like is used. The metal oxide film may be a single film, or may be a form in which a plurality of metal oxide films are stacked. In the case of the laminated form, the types of metal oxides may be different. Moreover, as a cold mirror, a silicon oxide and a titanium oxide are preferable.

Also in the present embodiment, the water / oil repellent film 30 is provided on the outermost side of the laminate 24 as in the first embodiment. Furthermore, by using a dielectric as the reflective film 36 as described above, the surface resistance on the surface 30S of the water / oil repellent film 30 is 1 × 10 ¹⁴ Ω even in the present embodiment in which no metal is used for the base material 20. / □ Adjusted to be below. As is clear from the above, also in this embodiment, the adhesion of dust to the surface 30S is prevented.

  In addition, the glass used as the base material 20 of this embodiment is borosilicate glass, soda-lime glass, optical glass, etc., for example. Moreover, resin as the base material 20 is, for example, a transparent resin such as polymethacrylate resin or polycarbonate resin, or a heat resistant resin such as polyphenylene sulfide.

  Similarly to the binder film 32, the reflective film 36 can be formed by a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or an ion plating method, or a chemical vapor deposition method such as thermal CVD or plasma CVD.

  As described above, according to the present embodiment, even when the base material 20 is formed of a general-purpose material, the mirror unit 18 having a good dustproof performance can be realized as in the first embodiment.

  The material, arrangement, and manufacturing method of each member included in the mirror unit 18 are not limited to the first and second embodiments. For example, in the first embodiment, a metal oxide may be used as the base material 20. This is because, as in the case of metal, the dustproof performance is improved and the molding process of the base material 20 is facilitated. Furthermore, in order to improve the light reflection characteristics on the reflection surface 20S of the base material 20 made of metal or metal oxide, the reflective film 36 of the second embodiment is formed on the reflection surface 20 of the first embodiment. Also good.

  On the other hand, in the mirror unit 18 of the second embodiment, when the base material 20 such as glass or resin having excellent light reflection characteristics is used, the reflective film 36 may not be provided. In this case, as in the first embodiment, the surface 20S of the substrate 20 functions as a reflecting surface. Also in the second embodiment, a fine uneven film (not shown) may be provided below the water / oil repellent film 30 (see paragraphs [0042] to [0045]).

It is a figure which shows roughly the rear projector provided with the mirror unit in 1st Embodiment. It is sectional drawing which expands and shows the mirror unit in 1st Embodiment. It is sectional drawing which expands and shows the mirror unit in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mirror unit 12 Optical unit 16 Screen 18 Mirror unit 20 Base material 20S Reflective surface 24 Laminated body 30 Water / oil repellent film 32 Binder film 36 Reflective film 36S Reflective surface

Claims (14)

A rear projector mirror unit for guiding projection light emitted from an optical unit to a screen,
A substrate having a reflective surface for reflecting the projection light;
A binder film formed on the reflective surface;
A mirror unit comprising: a water / oil repellent film formed on the binder film.   The mirror unit according to claim 1, wherein the base material is a metal.   The mirror unit according to claim 1, wherein the water / oil repellent film is provided on the outermost side of the laminate including the water / oil repellent film.   4. The mirror unit according to claim 1, wherein the water / oil repellent film includes a fluorine-containing organic polymer.   The mirror unit according to any one of claims 1 to 4, wherein a physical film thickness of the water / oil repellent film is 0.4 to 100 nm.   6. The mirror unit according to claim 1, wherein the binder film is made of silicon oxide.   The rear projector according to claim 1, wherein a physical film thickness of the binder film is 5 to 500 nm.   The rear projector according to claim 1, wherein the binder film is a dense film. 9. The mirror unit according to claim 1, wherein a surface resistance of the mirror unit is 1 × 10 ¹⁴ Ω / □ or less. A rear projector mirror unit for guiding projection light emitted from an optical unit to a screen,
A substrate;
A reflective film formed on the surface of the base material to form a reflective surface for reflecting the projection light;
A binder film formed on the reflective film;
A mirror unit comprising: a water / oil repellent film formed on the binder film.   The mirror unit according to claim 10, wherein the base material is glass or resin.   The mirror unit according to claim 10, wherein the reflective film is a dielectric. A rear projector comprising an optical unit that emits projection light, and a mirror unit that guides the projection light to a screen,
The mirror unit is
A base material having a reflecting surface for reflecting the projection light emitted from the optical unit;
A binder film formed on the reflective surface;
A rear projector comprising: a water / oil repellent film formed on the binder film. A rear projector comprising an optical unit that emits projection light, and a mirror unit that guides the projection light to a screen,
The mirror unit is
A substrate;
A reflective film formed on the surface of the base material to form a reflective surface that reflects the projection light emitted from the optical unit;
A binder film formed on the reflective film;
A rear projector comprising: a water / oil repellent film formed on the binder film.

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