JP2005266263A - Rear projector device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear projector device with which a high contrast image can be projected by eliminating the effect of outside light. <P>SOLUTION: The rear projector device 10 includes: a projecting part (projector light source 1) which projects image light; a reflecting mirror 2 which reflects light L<SB>P</SB>projected from the projecting part; and a screen 3 onto which light L<SB>R</SB>reflected from the reflecting mirror 2 is projected from back. The reflecting mirror 2 has reflection properties relative to light in a prescribed wavelength band corresponding to the image light, and also absorption properties relative to light in a visible wavelength band excepting the prescribed wavelength band. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rear projector apparatus including a projection unit that projects image light, a reflection mirror that reflects projection light from the projection unit, and a screen on which reflected light of the reflection mirror is projected from the back side. It is.

  In recent years, overhead projectors and slide projectors have been widely used as methods for presenting materials by a speaker in a conference or the like. In general households, video projectors and moving picture film projectors using liquid crystals are becoming popular. In these projector projection methods, light output from a light source is modulated by, for example, a transmissive liquid crystal panel to form image light, and the image light is emitted through an optical system such as a lens and projected onto a screen. To do.

  For example, a projector device capable of forming a color image on a screen separates light rays emitted from a light source into red (R), green (G), and blue (B) colors and converges them on a predetermined optical path. An illumination optical system, a liquid crystal panel (light valve) that optically modulates the RGB light beams separated by the illumination optical system, and a light combining unit that combines the RGB light beams light-modulated by the liquid crystal panel, The color image synthesized by the light synthesizing unit is enlarged and projected on a screen by a projection lens.

  Recently, a projector device has been developed that uses a narrow-band three-primary-color light source as a light source, and spatially modulates the luminous flux of each RGB color using a grating light valve (GLV) instead of a liquid crystal panel. Yes.

  In the projector apparatus described above, a projector screen is used to view a projected image. This projector screen is roughly divided into a front projector screen for irradiating projection light from the front side of the screen and viewing the reflected light on the screen, and a projection light from the back side of the screen for transmission through the screen. There is a rear projector screen for viewing light from the front side of the screen. In either method, the image displayed on the screen is required to have high contrast.

  A recent rear projector screen has been proposed in which contrast is improved by forming a light-shielding layer 105 made of black stripes corresponding to the non-condensing portion of the lenticular lens 100 as shown in FIG. 12 (for example, , See Patent Document 1).

JP 2003-131325 A

  However, even in the rear projector screen described above, since the outside light that has entered through the gap between the black stripes of the light shielding layer is re-reflected in the projector device and projected onto the screen, the drop of black as an image becomes insufficient, and as a result, the contrast Had a problem of getting worse.

  The present invention has been made in view of the above problems in the prior art, and an object of the present invention is to provide a rear projector device that can project an image with high contrast while eliminating the influence of external light.

  That is, the invention of claim 1 includes a projection unit that projects image light, a reflection mirror that reflects the projection light from the projection unit, and a screen on which the reflected light of the reflection mirror is projected from the back side. In the rear projector apparatus, the reflection mirror has a reflection characteristic with respect to light in a specific wavelength region corresponding to the image light, and has an absorption characteristic with respect to light in a visible wavelength region excluding the specific wavelength region. It is characterized by that.

  In the present invention, the image light projected from the projection unit is reflected by the reflection mirror and projected onto the screen. On the other hand, external light incident through the screen is almost absorbed by the reflection mirror that absorbs light in the wavelength region excluding image light. Accordingly, since the ratio of the external light reflected by the reflecting mirror is greatly reduced, it is possible to project a high-contrast image on the screen.

In the reflection mirror having such selective reflection characteristics, for example, an optical multilayer film of at least two layers including a dielectric film and a light-absorbing thin film having transparency is formed on a reflection layer that reflects visible light. Obtained by. The dielectric film is made of a transparent material at least in the visible wavelength region, and for example, Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or SiO ₂ is used. The light-absorbing thin film having transparency is preferably formed to a thickness of 5 to 20 nm with a material having a refractive index of 1 or more and an absorption coefficient of 0.5 or more. Examples of such materials include Nb, Nb-based alloys, C, Cr, Fe, Ge, Ni, Pd, Pt, Rh, Ti, TiN, TiN _x W _y , Mn, Ru, and PbTe. Each film of such an optical multilayer film can be formed by sputtering, for example. Although a thermosetting resin, a UV curable resin, or the like can be used as the dielectric, in this case, the dielectric film can be formed by a coating method. The reflective layer on which the optical multilayer film is formed is preferably a metal substrate or a substrate such as a plastic on which a metal film is formed.

In another example of the reflection mirror having the selective reflection characteristic, a high refractive index film and a low refractive index film having a lower refractive index than the high refractive index film are alternately formed on an absorption layer that absorbs visible light. It is obtained by forming an optical multilayer film laminated on the substrate. The high refractive index film is preferably made of TiO ₂ , Nb ₂ O ₅ or Ta ₂ O ₅ , and the low refractive index film is preferably made of SiO ₂ or MgF ₂ . Each film of such an optical multilayer film can be formed by sputtering, for example. Alternatively, the high refractive index film and the low refractive index film may be optical films formed by applying a paint containing a resin that absorbs energy and causes a curing reaction. The reflective layer on which the optical multilayer film is formed is preferably a substrate containing black particles, or a substrate such as plastic on which a black film is formed.

The reflection mirror is preferably curved in the vertical direction of the screen.
As a result, since the incident angle of the image light projected from the projection unit is within a certain range at any incident position of the reflection mirror (optical multilayer film), the wavelength of the light reflected by the reflection mirror (optical multilayer film) Since the area is within a certain range, the viewer can view an image with little color tone variation over the entire screen.

Alternatively, it is preferable that the reflection mirror has different selective reflection characteristics corresponding to the incident angle of the projection light.
As a result, the wavelength region of the reflected light is adjusted according to the incident angle of the image light projected from the projection unit at any incident position of the reflecting mirror (optical multilayer film). ) Is within a certain range, the viewer can view an image with little color tone fluctuation on the entire screen.

  The specific wavelength region preferably includes a wavelength region of each color of red light, green light, and blue light.

  According to the present invention, the reflection mirror selectively reflects only light in the wavelength region related to the image light out of the projection light from the projector light source, and does not reflect light in other wavelength regions such as external light. It is possible to project a high contrast image.

Hereinafter, a first embodiment of a rear projector apparatus according to the present invention will be described.
FIG. 1 is a cross-sectional view showing a configuration of a rear projector apparatus according to the present invention.
The rear projector 10 includes a projector light source 1 is one embodiment of a projection unit for projecting the image light, a reflecting mirror 2 which reflects the projection light (projector light) L _P from the projector light source 1, reflective mirror 2 reflecting light L _R is projected from the back side, and a screen 3 for emitting a viewer side as the image light L _i.

  The projector light source 1 may be any projector light source as long as it is used as a light source of a normal rear projector device, and uses light including wavelength regions of the three primary colors of red (R), green (G), and blue (B). It is preferable to project image light. For example, any one of a laser oscillator, an LED, a metal halide lamp, a high-pressure mercury lamp, and a xenon lamp and an illumination optical system corresponding thereto are provided. Among them, the laser oscillator is preferably one that emits three primary color narrowband light composed of the wavelength regions of the three primary colors of RGB, for example, a laser oscillator that emits red light having a wavelength of 642 nm, and green light having a wavelength of 532 nm. And a laser oscillator that emits blue light having a wavelength of 457 nm.

Reflecting mirror 2 has a reflection characteristic for light of a specific wavelength region corresponding to the projector light L _P is an image light, having absorption properties with respect to light in a visible wavelength region excluding the specific wavelength range . Here, it is preferable that the specific wavelength region includes a wavelength region of light of each of the three primary colors RGB used as image light by the projector light source 1.

  FIG. 2 shows an example in which the reflective mirror 2 includes a dielectric film 22D, an optical multilayer film 22 made of a light-absorbing thin film 22M having transparency, and a reflective layer 21.

  Here, the reflective layer 21 has a metal film 21M formed on the substrate 21B and reflects the light transmitted through the optical multilayer film 22.

  The substrate 21B serves as a support for the reflection mirror 2, and can be made of, for example, polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyolefin (PO), or the like. Examples thereof include a polymer having flexibility.

The metal film 21M may be any metal material that reflects visible light with high reflectivity. For example, it is made of Al, Au, or Ag, and a film thickness of 50 nm or more is preferable. As a method for forming the metal film 21M on the substrate 21B, any method such as vapor deposition, plating, and coating may be used.
As the reflective layer 21, a metal substrate made of the same material as the metal film 21M may be used instead of the metal film 21M formed on the substrate 21B of FIG.

  The optical multilayer film 22 is a film having a selective reflection characteristic of at least two layers including a dielectric film 22D and a light-absorbing thin film 22M having transparency. In this case, a structure in which the dielectric films 22D and the light-absorbing thin films 22M having transparency are alternately stacked may be employed, or a structure in which a plurality of types of dielectric films 22D are continuously stacked may be employed.

The dielectric film 22D is made of a transparent material at least in the visible wavelength region, and for example, Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or SiO ₂ is used. Note that the greater the refractive index of the dielectric film 22D, the larger the half-value width of the reflection peak in the wavelength region of each color light in the three primary color wavelength regions, and the smaller the refractive index, the smaller the half-value width tends to be smaller. The dielectric material may be appropriately selected according to the selective reflection characteristics.

The light-absorbing thin film 22M having transparency is a thin film formed with a material having a refractive index of 1 or more and an absorption coefficient of 0.5 or more, preferably in a thickness of 5 to 20 nm. Examples of such materials include Nb, Nb-based alloys, C, Cr, Fe, Ge, Ni, Pd, Pt, Rh, Ti, TiN, TiN _x W _y , Mn, Ru, and PbTe. Each film of the optical multilayer film 22 may be formed by a dry process such as sputtering.

Each film thickness of the optical multilayer film 22 has, for example, high reflectivity with a reflectance of 80% or more for the light of the three primary color wavelength regions composed of light in the wavelength regions of red, green, and blue, and the three primary colors. For light in a wavelength region other than the wavelength region, it is designed to have a high absorption characteristic with an absorptivity of 80% or more, for example. Here, each film thickness of the optical multilayer film 22 is such that the thickness of each film is d, the refractive index of each film is n, and the wavelength of light incident on the optical multilayer film is λ. The target thickness nd is preferably designed so as to satisfy the following expression (1) with respect to the wavelength λ of the incident light.
nd = λ (α ± 1/4) (1)
(However, α is a natural number.)

For example, the metal film 21M is an Al film (film thickness 50 nm), and the optical multilayer film 22 is a three-layer structure of Nb ₂ O ₅ / Nb / Nb ₂ O ₅ (each film thickness: 551 nm / 15 nm / 551 nm). As shown in FIG. 3, the projector light (light from the projector light source using the laser oscillator) has a high reflectance of 80% or more with respect to light in the three primary color wavelength regions, It can be set as the reflective mirror 2 which has a high absorption factor of 80% or more with respect to wavelength range light (stray light). FIG. 3 shows a case where the projector light is perpendicularly incident on the reflection mirror 2 (incident angle is 0 °).

In addition, by using multiple dielectric films and adjusting the film thickness, the half-value width and peak height of each reflection peak in the wavelength region of each color light in the three primary color wavelength regions can be adjusted separately. It is. For example, the metal film 21M is made of an Al film (film thickness 50 nm), and the optical multilayer film 22 has a three-layer structure of SiO ₂ / Nb ₂ O ₅ / Nb (each film thickness: 554 nm / 327 nm / 6 nm). In addition, the reflectance in the green region can be lowered with respect to the red region. Thus, even when a projector light source having a poor luminance balance such that the luminance of the green region is higher than that of the blue and red regions is used, the luminance balance of the three primary colors can be achieved.

4, as another configuration of the reflecting mirror 2, among the wavelength regions of the projector light L _P on the substrate 21B, has a reflection characteristic for light in the wavelength region of each color light of RGB three primary colors, the wavelength region An example in which an optical multilayer film 23 having transmission characteristics with respect to light other than the above and a light absorption layer 24 on the back surface of the substrate 21B is shown. Here, the substrate 21B may be the same as the substrate shown in FIG.

  The optical multilayer film 23 is a film having selective reflection characteristics in which a high refractive index film 23H and a low refractive index film 23L having a refractive index lower than that of the high refractive index film 23H are alternately stacked.

  The high refractive index film 23H and the low refractive index film 23L can be formed by any method of a dry process such as sputtering, or a wet process such as spin coating or dip coating.

In the case of forming by a dry process, various materials can be used as the constituent material of the high refractive index film 23H as long as the refractive index is about 2.0 to 2.6. Similarly, the constituent material of the low refractive index film 23L has a refractive index of about 1.3 to 1.5, and various materials can be used. For example, the high refractive index film 23H may be made of TiO ₂ , Nb ₂ O ₅ or Ta ₂ O ₅ , and the low refractive index film 23L may be made of SiO ₂ or MgF ₂ .

When formed by a dry process, the thickness of each optical multilayer film 23 is such that the optical thin film has high reflection characteristics with respect to light in a specific wavelength band by simulation based on the matrix method, and at least visible light other than the wavelength band light is visible. The film thickness may be designed so as to have high transmission characteristics for light in the wavelength band. The simulation based on the matrix method here is a method disclosed in Japanese Patent Application Laid-Open No. 2003-270725, and an angle θ is applied to a multilayer optical thin film system that is composed of a plurality of different materials and causes multiple reflection at the boundary of each layer. _When light is incident at ₀ , the phase is aligned depending on the type and wavelength of the light source to be used and the optical film thickness (product of refractive index and geometric film thickness) of each layer, and the reflected light velocity shows coherence. A simulation is performed using an equation based on a principle that causes cases to interfere with each other, and a film thickness of an optical film having desired characteristics is designed.

  In the present invention, as the specific wavelength regions, the wavelength regions of the three primary colors of RGB used as image light by the projector light source 1 are selected, and only light in these wavelength regions is obtained by simulation based on the matrix method. The film thickness may be designed to reflect and transmit light in a wavelength region other than these wavelength regions. By superposing the high-refractive index film 23H and the low-refractive index film 23L having such a thickness, the optical multilayer film 23 that functions well as a three primary color wavelength band filter can be reliably realized.

  Further, the number of layers of the optical film constituting the optical multilayer film 23 formed by the dry process is not particularly limited and can be set to a desired number of layers. It is preferable that the outer layer is composed of an odd-numbered layer that is a high refractive index film 23H.

When the optical multilayer film 23 is formed by a wet process, a high refractive index film 23H obtained by applying and curing a solvent-based paint for a high refractive index film, and an optical having a lower refractive index than the high refractive index film 23H. It is preferable to use an odd layer in which low-refractive-index films 23L obtained by applying and curing a solvent-based paint for a low-refractive-index film to be a film are alternately laminated. Each optical film may be formed by applying a paint containing a resin that absorbs energy applied by heating, ultraviolet irradiation, or the like and causes a curing reaction. For example, the high refractive index film 23H is formed of a thermosetting resin JSR Opster (JN7102, refractive index 1.68), and the low refractive index film 23L is a thermosetting resin JSR Opster (JN7215, refractive index 1.41). ). Thereby, the optical multilayer film 23 has flexibility.
Here, the high refractive index film 23 </ b> H is not limited to the thermosetting resin, and may be a solvent-based paint that can secure a refractive index of about 1.6 to 2.1. The low refractive index film 23L is not limited to the thermosetting resin, and may be a solvent-based paint that can secure a refractive index of about 1.3 to 1.59. Note that the larger the difference in refractive index between the high refractive index film 23H and the low refractive index film 23L, the smaller the number of layers.

  When formed by a wet process, each film thickness of the optical multilayer film 23 is, for example, highly reflective with, for example, a reflectance of 80% or more with respect to light in the three primary color wavelength regions composed of light in the wavelength regions of red, green, and blue. In addition to having the characteristics, it is designed to have a high transmission characteristic of, for example, a transmittance of 80% or more with respect to light in a wavelength band other than the three primary color wavelength band lights. Here, each film thickness of the optical multilayer film 23 is preferably designed to satisfy the above formula (1).

  For example, the film thickness of the high refractive index film 23H (refractive index 1.68) is 1023 nm, the film thickness of the low refractive index film 23L (refractive index 1.41) is 780 nm, the high refractive index film 23H, and the low refractive index film 23L. As shown in FIG. 5, the projector light (the above-mentioned laser) is formed by forming the optical multilayer film 23 having a nine-layer structure in which nine layers are alternately stacked and a high refractive index film 23H is stacked on the stacked layers. Light from a projector light source using an oscillator) has a high reflectance of 80% or more for light in the three primary color wavelength ranges, and has reflectance for wavelength range light (stray light) before and after the three primary color wavelength ranges. It can be set as the film | membrane which has a high permeation | transmission characteristic of 20% or less.

  The absorption layer 24 is formed by applying a black paint film or a black film formed by applying a black paint on the back surface of the substrate 21B, and has a function of absorbing light. As a result, the light transmitted through the optical multilayer layer 23 is absorbed by the absorption layer 24 and reflection of the transmitted light can be prevented, and the reflection mirror 2 can more reliably obtain only the light in the three primary color wavelength regions as the reflected light. It becomes. Further, the substrate 21B itself may function as an absorption layer by adding black paint or the like to the substrate 21B to make the color of the substrate 21B black.

  In any of the above-described reflection mirrors 2, light in a specific wavelength region (three primary color wavelength regions) corresponding to light projected from the projector light source 1 is reflected with a light reflectance, and light outside the specific wavelength region is reflected. It is possible to absorb (external light incident through the screen 3).

Hereinafter, the embodiment will be described by taking the reflection mirror 2 having the configuration of FIG. 2 as an example.
Assuming that the reflecting mirror 2 has a flat plate shape, the incident angle of the projector light varies depending on the position of the reflecting mirror 2 in the vertical direction of the screen 3 as shown in FIG. That is, in the distant the relationship from the projector light source 1 than the incident position P _y is incident position P _x of the projector light on the reflecting mirror 2, than the incident angle x of the projector light L _Px at the incident position P _x, incident position P The incident angle _y of the projector light L _Py at y increases. The variation of the incident angle becomes larger as the rear projector device becomes larger, for example.

  On the other hand, in the optical multilayer film 22, the optical characteristics tend to change when the incident angle of the projector light changes. This is shown in FIG. As the incident angle increases from 0 ° to 40 °, the wavelength region having high reflectance in each of the RGB wavelength regions shifts to the short wavelength side.

  Accordingly, when the reflection mirror 2 has a flat plate shape and the optical multilayer film 22 having uniform optical characteristics is formed, it is reflected by the optical multilayer film 22 depending on the incident position of the projector light on the reflection mirror 2 in the vertical direction of the screen 3. Since the wavelength region of the emitted light varies, the color of the image light emitted from the screen 3 varies in the vertical direction of the screen 3.

Therefore, in the present invention, by curving the reflecting mirror 2 as shown in FIG. 8 in the vertical direction of the screen 3, a configuration in which the incident angle of the projection light L _P from the projector light source 1 to the reflecting mirror 2 is adjusted . As a result, the incident angles (a, b, c) are within a certain range at any incident position (P _a , P _b , P _{c in the} figure) on the reflection mirror 2 and reflected by the optical multilayer film 22. since the wavelength region of the light L _R is within a certain range, the viewer becomes possible to watch an image with little color variation through the screen 3.
Here, the curvature of the reflection mirror 2 is preferably adjusted so that, for example, the incident angle of the projector light is 20 ° or less.

The screen 3 may have a configuration of a conventionally known screen used in a rear projector device, and includes, for example, a Fresnel lens that converts reflected light from a reflecting mirror into parallel light, and a diffusion plate that diffuses and emits the parallel light. Just use clean.
Further, a configuration including a Fresnel lens, a lenticular lens, a black stripe, and a diffusion plate from the reflection mirror 2 side may be used. Specifically, a screen having the configuration shown in FIG. 12 may be used.
Among these screens, it is preferable to use a screen having a light-shielding layer made of black stripes, in combination with the effects of the present invention, because a higher contrast image can be obtained.

With the above structure (Fig. 1), when the projection light L _P from the projector light source 1 is incident to the reflecting mirror 2, is reflected by the light only high reflectivity of RGB three primary-color wavelength regions with an optical multilayer film 22, other wavelengths of Area light is absorbed. Alternatively, only light in the RGB three primary colors wavelength region is reflected by the optical multilayer film 23 with a high reflectance, and light in other wavelength regions is absorbed by the light absorption layer 24. Then, the reflected light L _R reflected by the reflecting mirror 2 passes through the screen 3, to reach the viewer's side as the image light L _i.
In addition, the external light L _O entering from the viewer side includes light entering the projector device through the gap between the black stripes provided in the non-condensing part of the lenticular lens of the screen 3, but the optical multilayer film of the reflection mirror 2. 22 or light absorption layer 24. As a result, an image with higher contrast than that of the conventional rear projector apparatus can be obtained.

Next, a second embodiment of the rear projector apparatus according to the present invention will be described.
In the present embodiment, the configuration for dealing with the problem that the incident angle varies depending on the incident position of the projector light on the reflection mirror 2 is different from the first embodiment, and the other configuration is the same as the first embodiment. Hereinafter, only the configuration of the reflection mirror 2 different from that of the first embodiment will be described.

FIG. 9 is a view of the reflection mirror 2 as viewed from the side where the optical multilayer film 22 is provided.
The optical multilayer film 22 has different selective reflection characteristics in the vertical direction of the screen corresponding to the incident angle of the projection light from the projector light source 1, and in FIG. 9, the optical multilayer film 22 is divided into three regions A, B, and C in the vertical direction of the screen. The optical characteristics are formed differently for each of the regions A, B, and C. Region A is a region far from the projector light source 1, that is, a region where the incident angle of the projector light is large, and region C is a region close to the projector light source 1, and a region where the incident angle of the projector light is small. .

FIG. 10 shows an example of the optical characteristics for each of the regions A, B, and C. Here, a case is shown in which projector light is incident on the optical multilayer film 22 perpendicularly (incident angle 0 °).
Here, with reference to the optical characteristics of the optical multilayer film 22 in the region C, as the incident angle of the projector light increases, that is, the optical characteristics in which the peaks showing the high reflectance in the order of the regions B and C are shifted to the longer wavelength side. It has become. In this case, the film design is such that the optical characteristics are shifted in advance in accordance with the incident angle of the projector light, and the wavelength region of the light that is actually reflected falls within a certain range as the entire reflection mirror 2. The method based on 1) may be performed. Also in this embodiment, the configuration of the optical multilayer film 23 shown in FIG. 4 can be applied. In this case, the method based on the formula (1) or the method based on the simulation based on the matrix method may be used.

11 shows a configuration in which the wavelength region of the reflected light L _R of the reflecting mirror 2 by the present embodiment is housed in the wavelength region of a predetermined range. That is, the incident angle (i, h, g) increases according to the incident position (P _i , P _h , P _g ) on the reflection mirror 2, but in the order of the regions C, B, A of the optical multilayer film 22. by the optical characteristics are shifted to the long wavelength side, as a result of the wavelength region of reflected at each position is adjusted, the wavelength region of the reflected light L _R is within a certain range, the viewer screen It is possible to view an image with little color tone fluctuation through 3.

  In addition, although the aspect which divides the area | region of the optical multilayer film 22 in the position on the reflective mirror 2 like FIG. 9 was shown, even if it is an aspect which changes a selective reflection characteristic continuously in the up-down direction of the reflective mirror 2, FIG. Good. In this case, for example, when the optical multilayer film 22 is formed (at the time of sputtering), an inclined film in which the film thickness of the optical multilayer film 22 continuously changes so as to shift the optical characteristics in advance according to the incident angle of the projector light. do it.

  In the present embodiment as described above, an image having a higher contrast than that of the conventional rear projector device can be obtained by the same effect as that of the first embodiment.

1 is a schematic cross-sectional view showing a configuration of a rear projector device according to the present invention. It is a figure which shows the optical film structure (1) of the reflective mirror 2. FIG. FIG. 6 is a diagram showing optical characteristics of the optical multilayer film 22. It is a figure which shows the optical film structure (2) of the reflective mirror 2. FIG. FIG. 6 is a diagram showing optical characteristics of an optical multilayer film 23. It is the schematic which shows the relationship between the incident position and incident angle of the projector light on a reflection mirror when it is assumed that the reflection mirror 2 is flat form. It is a figure which shows the incident angle dependence of the optical characteristic in the optical multilayer film 22 of the projector light. It is a figure which shows the structural example of the reflective mirror 2 in the 1st Embodiment of this invention. It is a figure which shows the example of an optical film structure of the optical multilayer film 22 in the 2nd Embodiment of this invention. It is a figure which shows the optical characteristic for every area | region of the optical multilayer film 22 in the 2nd Embodiment of this invention. It is a figure which shows the structural example of the reflective mirror 2 in the 2nd Embodiment of this invention. It is a figure which shows the structural example of the screen applied by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector light source, 2 ... Reflection mirror, 21B ... Substrate, 21M ... Metal film, 22, 23 ... Optical multilayer film (optical multilayer film), 3 ... Screen, 10 ... Rear projector apparatus, 22D ... Dielectric film, 22M ... Light absorption thin film, 23H: High refractive index film, 23L: Low refractive index film, 24 ... Absorption layer, 90 ... Fresnel lens sheet, 91 ... Light diffusion substrate, 92 ... Fresnel lens part, 93 ... Cylindrical lens group, 100 ... Lenticular Sheet, 101 ... Substrate, lens part ... 102, 105 ... Light-shielding part, 106 ... UV curable resin layer, 201 ... Light diffusion plate, 207 ... Adhesive layer, _Li ... Video light, _Lp ... Projector light, _LR ... Reflected light, L _o ... External light

Claims (12)

In a rear projector device including a projection unit that projects image light, a reflection mirror that reflects projection light from the projection unit, and a screen on which reflected light of the reflection mirror is projected from the back side,
The reflection mirror has a reflection characteristic with respect to light in a specific wavelength region corresponding to the image light, and has an absorption characteristic with respect to light in a visible wavelength region excluding the specific wavelength region. Rear projector device.   The reflection mirror includes at least two or more optical multilayer films composed of a dielectric film and a light-absorbing thin film having transparency, and a reflective layer that reflects light transmitted through the optical multilayer film. Item 4. The rear projector device according to Item 1.   3. The rear projector apparatus according to claim 2, wherein the dielectric film is made of a material transparent at least in a visible wavelength region, and the light absorption thin film is made of a material having a refractive index of 1 or more and an absorption coefficient of 0.5 or more. . The material of the dielectric film is Nb ₂ O ₅ , TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ or SiO ₂ , and the material of the light absorption thin film is Nb, Nb-based alloy, C, Cr, Fe, Ge The rear projector apparatus according to claim 3, wherein the rear projector apparatus is Ni, Pd, Pt, Rh, Ti, TiN, TiN _x W _y , Mn, Ru, or PbTe.   The rear projector apparatus according to claim 2, wherein the reflective layer is a metal substrate or a metal film formed on the substrate.   The reflection mirror includes an optical multilayer film in which a high refractive index film and a low refractive index film having a lower refractive index than the high refractive index film are alternately stacked, and an absorption layer that absorbs light transmitted through the optical multilayer film. The rear projector apparatus according to claim 1. The rear projector apparatus according to claim 6, wherein the high refractive index film is made of TiO ₂ , Nb ₂ O ₅ or Ta ₂ O ₅ , and the low refractive index film is made of SiO ₂ or MgF ₂ .   7. The rear projector apparatus according to claim 6, wherein the high refractive index film and the low refractive index film are optical films formed by applying a paint containing a resin that absorbs energy and causes a curing reaction. .   The rear projector apparatus according to claim 6, wherein the absorption layer is a substrate containing black particles or a black film formed on the substrate.   The rear projector apparatus according to claim 1, wherein the reflection mirror is curved in the vertical direction of the screen.   The rear projector apparatus according to claim 1, wherein the reflection mirror has different selective reflection characteristics corresponding to an incident angle of the projection light.   The rear projector apparatus according to claim 1, wherein the specific wavelength region includes a wavelength region of each color of red light, green light, and blue light.

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