JP2007147939A - Front projection screen and on-board projector system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a front projection screen which is used to view images on the front of the screen by projection light from a projector and also used to view the outside sceneries at the front from the back through it, and an on-board projector system. <P>SOLUTION: This screen includes a reflection sheet 1 having a high reflection property to light in the specific wavelength range including the wavelength range of the projection light, and having a high transmissivity for the light in the wavelength range other than the above specific wavelength range, and a light diffusion sheet 3 to scatter and radiate the reflected light from the reflection sheet 1. The light diffusion sheet 3 has an area 3a to pass or transmit the incident light from the front of the screen to the back reflection sheet 1 without changing its optical characteristics, and passes or transmits the external light from the front of the screen through the area 3a of the light diffusion sheet 3 and further through the above reflection sheet 1 to make it possible to view the outside sceneries from the back of the screen. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a front projection screen and an in-vehicle projector system.

  In recent years, a motor vehicle having a driver's seat and a rear seat, such as a wagon-type private car, has a projector system comprising a front projection screen and a projector so that passengers in the rear seat can watch movies etc. It has come to be.

  In this case, since the projection light from the projector is reflected by the front projection type screen and the image is displayed, the front projection type screen is provided in the rear of the driver seat and in the front of the rear seat. It is provided closer to the rear seat than the screen.

  Here, when the driver who is a driver's seat passenger tries to check the back while driving the vehicle, this front projection type screen comes into the field of view, and the field of view is narrower than before was there.

  In order to solve this problem, the screen is provided with a slit in the stripe or a dot-shaped through hole, and the driver can see the back through the hole to secure a field of view. . However, along with this, since the projection light from the projector has reached the driver through this hole, a new problem has arisen that the driver is obscured by this light.

  In order to solve this problem, for example, Patent Document 1 proposes a polarizing screen. By using this screen, the projection light from the projector can be seen through the front surface side of the screen from the back surface (driver side) without passing through the back surface side of the screen.

  However, the present invention is effective only for a liquid crystal projector as a projector, and a sufficient effect cannot be obtained when a projector that projects non-polarized light such as a DLP projector is used.

JP 2001-255586 A

  The present invention has been made in view of the above problems in the prior art, and is not limited to the type of projector, and on the screen front surface side, an image produced by light projected from the projector can be viewed. An object of the present invention is to provide a front projection type screen and an in-vehicle projector system capable of seeing the scenery on the front side of the screen through the screen from the back side.

  The present invention provided in order to solve the above-mentioned problems consists of a plurality of layers in which several kinds of optical films having different refractive indexes are laminated, and has high reflection characteristics for light in a specific wavelength region including the wavelength region of projection light. An optical multilayer film having high transmission characteristics with respect to light in a wavelength region other than the specific wavelength region, and provided on the optical multilayer film to scatter and radiate reflected light from the optical multilayer film A front-projection screen that reflects the projection light from the front surface side of the screen and displays it as an image, wherein the light diffusion layer is on the front surface side of the screen The region A allows the incident light from the screen to pass or transmit to the optical multilayer film side of the back surface without changing its optical characteristics, and external light from the front surface side of the screen is region A of the light diffusion layer. Pass through or pass through, and By transmitting membrane is a front projection screen, characterized in that from the screen back surface side viewable views the screen front side (claim 1).

  Here, the region A is preferably a plurality of holes penetrating the light diffusion layer.

Moreover, it is good to provide the semi-absorption board which is provided in the opposite surface to the said light-diffusion layer of the said optical multilayer film, and absorbs a part of external light.
Or it is good to provide the polarizing plate which is provided in the opposite surface to the said light-diffusion layer of the said optical multilayer film, and absorbs a part of external light.

  The present invention provided to solve the above-described problems includes a front projection screen according to any one of claims 1 to 4 and a projector serving as a light source of the projection light, and includes a driver seat and a rear seat. An on-vehicle projector system mounted on a motor vehicle having the front projection screen provided behind a driver seat and in front of a rear seat, and the projector provided closer to the rear seat than the front projection screen. An in-vehicle projector system characterized by the above-mentioned.

  Here, it is preferable that the rear window of the motor vehicle includes a selective reflection filter that reflects light in the specific wavelength region.

  In addition, it is preferable that the rearview mirror of the motor vehicle includes a selective reflection filter that absorbs light in the specific wavelength region and reflects light outside the specific wavelength region.

The present invention provided to solve the above problems includes a front projection screen that reflects part of incident light and transmits the remaining light, and a projector that projects light in a specific wavelength region onto the front projection screen. An in-vehicle projector system mounted on a motor vehicle having a driver seat and a rear seat, wherein the front projection screen is provided in the rear of the driver seat and in front of the rear seat, and the projector is provided by the front projection screen. Is also provided on the rear seat side,
An on-vehicle projector system comprising a selective reflection filter that absorbs light in the specific wavelength region and reflects light outside the specific wavelength region in a rearview mirror of the motor vehicle.

According to the front projection screen of the present invention, the projection light (light in the specific wavelength region) from the front surface side of the screen is reflected by the optical multilayer film and scattered in a region other than the region A of the light diffusion layer. By doing so, it is possible to display a high-contrast image on the front side of the screen without being affected by external light. On the other hand, external light incident from the front surface side of the screen passes or transmits through the region A of the light diffusing layer, and further passes through the optical multilayer film, so that the screen front surface side from the screen rear surface side. You can see the scenery.
According to the in-vehicle projector system of the present invention, a passenger in the rear seat can view a high-contrast image displayed on the front projection screen, and the driver can block the rear view from the front projection screen. It will be possible to secure sufficient visibility.

The configuration of the front projection screen according to the present invention will be described below.
FIG. 1 is a cross-sectional view showing a configuration of a front projection screen which is a premise of the present invention.
As shown in FIG. 1, the front projection screen 10 has a configuration in which a reflection sheet 1 and a light diffusion sheet 3 are bonded together.

  In FIG. 2, the structural example of the reflective sheet 1 is shown. The reflection sheet has a high reflection characteristic with respect to light in the wavelength areas of light of the three primary colors of RGB among the wavelength areas of the projector light on the substrate 11, and has a high transmission characteristic with respect to light other than the wavelength areas. The optical multilayer film 12 having

  The substrate 11 serves as a support for the reflective sheet 1 and is 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 optical multilayer film 12 is formed by laminating a plurality of types of optical films having different refractive indexes. For example, a high refractive index film 12H made of a high refractive index material and a low refractive index having a lower refractive index than the high refractive index film 12H. This is a film having selective reflection characteristics in which low refractive index films 13L made of materials are alternately laminated.

  The high refractive index film 12H and the low refractive index film 12L can be formed by any 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 12H as long as the refractive index is about 2.0 to 2.6. Similarly, the constituent material of the low refractive index film 12L has a refractive index of about 1.3 to 1.5, and various materials can be used. For example, the high refractive index film 12H may be made of TiO ₂ , Nb ₂ O ₅ or Ta ₂ O ₅ , and the low refractive index film 12L may be made of SiO ₂ or MgF ₂ .

When formed by a dry process, the thickness of each optical multilayer film 12 is determined so that the optical thin film has high reflection characteristics with respect to light in a specific wavelength band by simulation based on a 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 region, the wavelength region of each of the RGB three primary colors used as image light by the projector light source is selected, and only light in these wavelength regions is reflected by a simulation based on the matrix method. (FIG. 3 (a))) and the film thickness may be designed so that light in a wavelength region other than these wavelength regions is transmitted (FIG. 3 (b)). By superposing the high-refractive index film 12H and the low-refractive index film 12L having such thicknesses, the optical multilayer film 12 that functions well as a three primary color wavelength band filter can be reliably realized.

Specifically, the film thicknesses of the high refractive index film 12H and the low refractive index film 12L are set as follows. In general, when a material having a refractive index higher than that of the substrate material is laminated on a certain substrate, the target film thickness d satisfies the condition of the following formula (1) in order to cause a reflectance peak at the wavelength λ _c. There is a need.

d = m · (λ _c / 4) / n (1)
(D: target film thickness, m: odd number, λ _c : wavelength, n: refractive index of optical film)

Here, m is an optical distance (QWOT) with λ _c / 4 as a unit, and a reflectance peak is formed at the wavelength λ _c by making it an odd number. Further, the film thickness d increases or decreases in proportion to the value of m (QWOT number).

  Moreover, the number of layers of the optical film which comprises the optical multilayer film 12 formed by a dry process is not specifically limited, It can be made into a desired number of layers. Here, when the number of layers is increased, the band of the reflection wavelength of light of each of the RGB three primary colors can be narrowed, and the reflectance can be increased. In addition, it is preferable that the outermost layer on the light incident side and the opposite side is constituted by an odd number layer that is a high refractive index film 12H.

When the optical multilayer film 12 is formed by a wet process, a high refractive index film 12H 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 12H. It is preferable to use an odd-numbered layer in which low-refractive index films 12L obtained by applying and curing a low-refractive index film solvent-based paint 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 12H is formed of a thermosetting resin JSR Opster (JN7102, refractive index 1.68), and the low refractive index film 12L is a thermosetting resin JSR Opster (JN7215, refractive index 1.41). ). Thereby, the optical multilayer film 12 has flexibility.
Here, the high refractive index film 12 </ b> H is not limited to the thermosetting resin, and may be any solvent-based paint that can secure a refractive index of about 1.6 to 2.1. The low refractive index film 12L 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 12H and the low refractive index film 12L, the smaller the number of layers.

4 to 6 show specific examples of the reflection sheet 1.
FIG. 4 is a schematic cross-sectional view showing a specific configuration of the reflection sheet 1.
Here, the high refractive index film 12H is an Nb ₂ O ₅ layer having a refractive index of 2.38 (wavelength 550 nm), and the low refractive index film 12L is an SiO ₂ layer having a refractive index of 1.455 (wavelength 550 nm). An optical multilayer film 12 having a five-layer structure of Nb ₂ O ₅ / SiO ₂ / Nb ₂ O ₅ / SiO ₂ / Nb ₂ O ₅ was formed on the substrate 11 by a certain sputtering method. Note that, assuming that an LED projector is used as the projector, the thickness of each layer was set to 11 as the QWOT number.
The reflection characteristic of the obtained reflection sheet 1 is shown in FIG. 5, and the transmission characteristic is shown in FIG.

  In addition, as another structure of the reflection sheet 1, it is good also as a structure by which the optical multilayer film 12 of the same structure as the above was formed in both surfaces of the board | substrate 11, respectively.

  The light diffusion sheet 3 is provided on the optical multilayer film 12 and scatters the light reflected by the reflection sheet 1 to obtain scattered light.

  Since the front projection screen 10 includes the reflection sheet 1 and reflects light in the three primary color wavelength ranges, the observer views the reflected image of the image projected on the screen, that is, the front projection. Only the reflected light of the image projected on the mold screen 10 is seen. However, when the reflected light on the screen is only the reflective specular component, it is difficult to visually recognize a good image, which is disadvantageous for an observer such as a limited field of view, and a natural image cannot be visually recognized.

  Therefore, the reflection type screen 10 includes the light diffusing sheet 3 so that the scattered reflected light from the screen 10 can be viewed. That is, with the configuration in which the light diffusion sheet 3 is provided on the reflection sheet 1, the light incident through the light diffusion sheet 3 is selectively reflected by the reflection sheet 1 in a specific wavelength region. However, at this time, the reflected light is diffused when passing through the light diffusion sheet 3, and scattered reflected light other than the reflection specular component can be obtained. Since the reflected specular component and the scattered reflected light exist as the reflected light from the reflective screen 10, the observer can observe the scattered reflected light in addition to the reflected specular component. The characteristics are greatly improved. As a result, the observer can visually recognize a natural image.

  The light diffusing sheet 3 has a region 3a that allows incident light from the front surface side of the screen 10 to pass or transmit to the optical multilayer film 12 side on the back surface without changing its optical characteristics.

  Here, the region 3a is a space made of a through hole in the front and back direction of the light diffusion sheet 3 or a portion made of a material constituting the light diffusion sheet 3 but having no light diffusion function. In the case where the region 3a is a gap formed by through holes in the front and back direction of the light diffusing sheet 3, incident light is allowed to pass to the optical multilayer film 12 side on the back surface without changing its optical characteristics (FIG. 1). . Further, when the region 3a is a portion made of the material constituting the light diffusion sheet 3 but not having the light diffusion function, the incident light is transmitted to the optical multilayer film 12 side on the back surface without changing its optical characteristics. To be Note that, without changing the optical characteristics, the wavelength distribution of incident light is not changed, the light travels straight without being scattered, and the like when the incident light passes through or is transmitted through the region 3a. This means that there is no adverse effect on viewing the front side scenery from the back side of the projection screen 10.

In FIG. 7, the shape and arrangement example of the region 3a when viewed from the front surface side of the light diffusion sheet 3 are shown.
Here, the slit-shaped regions 3a having the same shape are arranged in parallel so as to form a stripe. The slit size of this area 3a may be large enough to visually recognize the scenery on the front side from the back side of the front projection screen 10 in relation to the slit interval. 0.01 mm is preferable. The slit length may be the screen length in the arrangement direction, but may be shorter than that. Further, the slit interval of the region 3a is not only small enough to visually recognize the front side scenery from the back side of the front projection screen 10, but also the front surface of the front projection screen 10. The interval needs to be large enough to allow the image displayed on the screen to be viewed. For example, the slit interval is preferably 1 to 0.01 mm. The slit length direction of the region 3a may be either the screen vertical direction or the horizontal direction.

In FIG. 8, the other shape and arrangement example of the area | region 3a at the time of seeing from the front surface side of the light-diffusion sheet 3 are shown.
Here, the dot-shaped regions 3a having the same shape are regularly arranged. The dot size of this area 3a may be large enough to visually recognize the scenery on the front side from the back side of the front projection screen 10 in relation to the dot distribution. 0.01 mm is preferable. Further, the dot distribution of the region 3a is not only a sufficiently small interval for viewing the front side scene from the back side of the front projection screen 10 when viewed as the interval between adjacent dots, The spacing needs to be large enough to allow the image displayed on the front projection screen 10 to be viewed on the screen. For example, the dot interval is preferably 3 to 0.01 mm. In FIG. 8, the dot shape is circular, but the dot shape is not limited to this, and may be any of a triangle, a quadrangle, a polygon, a star, an indefinite shape, and the like. Further, the dot arrangement may be irregular.

  The light diffusing sheet 3 has a conventionally known material, for example, a film composed of a layer in which beads are arranged, a film formed with a microlens array (MLA), a concavo-convex shape on the mold surface formed by sandblasting, etc. on the surface. It can be obtained by using a transferred film or the like and subsequently processing the film to form a region 3a which is a through hole having the shape and arrangement described above. Alternatively, in the case of producing a light diffusion sheet by transferring the uneven shape of the mold surface to the film surface, when the mold surface is processed, a portion corresponding to the position of the region 3a is flattened on the counterpart film surface. By processing in this way, the light diffusion sheet 3 in the present invention is obtained.

  According to the front projection screen 10 having the above-described configuration, an image of light projected from a projector can be viewed on the screen front side, and the screen front side through the screen from the back side of the screen. You can see the scenery.

  That is, the projection light Lp (light in the specific wavelength region) from the front surface side of the screen is reflected by the optical multilayer film 12 of the reflection sheet 1 and scattered in a region other than the region A of the light diffusion sheet 3. Thus, an image can be displayed on the front side of the screen. At this time, since only the projection light Lp from the projector is selectively reflected by the wavelength selective reflection function of the optical multilayer film 12, a high-contrast image can be displayed without being influenced by external light. On the other hand, the external light Lo incident from the front surface side of the screen passes or is transmitted through the region A of the light diffusion sheet 3, and light other than the specific wavelength region (RGB primary color wavelength region) passes through the optical multilayer film 12. Since it is transmitted, it is possible to see the scenery on the front side of the screen from the back side.

FIG. 9 shows a first modification of the front projection screen of the present invention.
The front projection screen 20 includes a semi-absorption filter 4 on the back surface of the front projection screen 10 (the surface opposite to the surface on which the light diffusion sheet 3 of the reflection sheet 1 is provided). Thereby, in addition to the function of the front projection screen 10, by absorbing a part of the light transmitted through the reflection sheet 1, the reflection of external light on the display screen of the front projection screen 20 is suppressed and the black level is reduced. Therefore, the display screen can have high contrast.
Examples of the semi-absorbing filter 4 include a filter in which carbon particles are dispersed in an acrylic film.

FIG. 10 shows a second modification of the front projection screen of the present invention.
The front projection screen 30 includes a polarizing filter 5 on the back surface of the front projection screen 10 (the surface opposite to the surface on which the light diffusion sheet 3 of the reflection sheet 1 is provided). Thus, in the case where the projection light from the projector is a polarization-controlled one (liquid crystal projector), in addition to the function of the front projection screen 10, half of the external light transmitted through the reflection sheet 1 is absorbed. Thus, the reflection of external light on the display screen of the front projection screen 30 is suppressed, and the display screen can have high contrast.
Examples of the polarizing filter 5 include a material obtained by impregnating and stretching iodine in polyvinyl alcohol.

Next, the in-vehicle projector system of the present invention will be described.
FIG. 11 shows the inside of the motor vehicle, and shows an outline of an embodiment of the in-vehicle projector system of the present invention.
The in-vehicle projector system of the present invention includes any one of the above-described front projection screens 10, 20, and 30 of the present invention and a projector 50 serving as a light source of the projection light, and includes a driver's seat 101 and a rear seat 102. In the in-vehicle projector system mounted on an automatic vehicle, the front projection screen 10 (20, 30) is provided behind the driver seat 101 and in front of the rear seat 102, and the projector 50 is connected to the front projection screen 10 ( 20, 30) on the rear seat 102 side.

Thereby, the passenger in the rear seat 102 can appreciate the high-contrast image displayed on the front projection screen 10 (20, 30), and the projection light from the projector 50 is reflected on the front projection screen 10 ( 20, 30) and is not transmitted through the screen, so the driver will not be dazzled by the light. Further, the external light Lo incident from the front surface side of the screen passes or is transmitted through the region A of the light diffusion sheet 3, and light other than the specific wavelength region (RGB primary color wavelength region) passes through the optical multilayer film 12. This allows the driver to ensure that the rear field of view is not obstructed by the front projection screen 10 (20, 30) and that a sufficient rear field of view can be secured.
Such effects of the invention can be obtained by projectors of any device (for example, a liquid crystal projector, a DLP projector, a three-pipe projector, etc.).

  Moreover, it is good to provide the optical filter which has the same wavelength selection function in the window glass of a motor vehicle together with the wavelength selection function of the optical multilayer film 12 in the front projection type screen 10 (20, 30). Thereby, the contrast of the display image of the front projection type screen 10 (20, 30) can be further improved.

  FIG. 12 shows a specific example. Here, in addition to the on-vehicle projector system of the present invention described above, a configuration is shown in which the reflection sheet 1 is attached to the rear window glass 103 of the motor vehicle.

  Although external light is incident on the rear side window glass 103, the light in the specific wavelength region (RGB three primary colors wavelength region) is reflected to the outside by the reflective sheet 1, and light outside the wavelength region passes through the reflective sheet 1 and passes through the interior of the vehicle. Incident light. Next, the light transmitted through the reflection sheet 1 of the rear side window glass 103 is incident on the front projection type screen 10 (20, 30), but is the light other than the specific wavelength region (RGB primary color wavelength region). The reflection sheet 1 is transmitted. Therefore, the influence of external light on the display screen of the front projection screen 10 (20, 30) is suppressed, and the contrast can be further improved.

  Further, in combination with the wavelength selection function of the optical multilayer film 12 in the front projection screen 10 (20, 30), the specific wavelength region (RGB primary color wavelength region) is absorbed by the rearview mirror (room mirror) 104 of the motor vehicle. A reflection sheet 40 may be provided. The configuration is shown in FIG.

  The reflection sheet 1 of the above-described front projection type screen 10 (20, 30) passes through the projection light from the projector 50 without being slightly reflected. Since the transmitted projection light reaches the driver via the rearview mirror 104, there is a problem that the driver is obscured by the light and the rear view cannot be confirmed.

  Therefore, in the present invention, the reflection sheet 40 is provided on the rearview mirror 104, and the reflection sheet 40 absorbs the projection light transmitted through the front projection screen 10 (20, 30) to solve this problem. ing.

  The reflection sheet 40 includes a reflection layer 42, a metal oxide film 43, and an optical multilayer film including a light-absorbing thin film 44 having transparency, on a substrate 41. And has a reflection characteristic with respect to light outside a plurality of specific wavelength regions. Here, the specific wavelength region includes wavelength regions of light of each color of red, green, and blue (RGB three primary colors) used as projection light of the projector.

FIG. 14 shows a cross-sectional configuration example of the reflection sheet 40.
The reflective sheet 40 includes a substrate 41, a reflective layer 42 made of Al (film thickness 50 nm), a metal oxide film 43 made of Nb ₂ O ₅ (film thickness 730 nm), and an Nb (film) in this order from the substrate 41 side. And a light-absorbing thin film 44 having a thickness of 3 nm).

FIG. 15 shows the reflection characteristics of the reflection sheet 40 having the configuration of FIG.
By sticking this reflection sheet 40 to the rearview mirror 104, the projection light (RGB light) of the projector among the light transmitted through the front projection screen 10 (20, 30) is absorbed, and the other light is absorbed. Since it is reflected, the driver can secure a rear view without being obscured by the projection light of the projector.

Next, FIG. 16 shows an outline of another embodiment of the in-vehicle projector system of the present invention. In the configuration of FIG. 16, only the front projection screen is different from the configuration of the in-vehicle projector system shown in FIG. 13, and the other components are the same.
Here, the front projection type screen 90 does not select and reflect / transmit the wavelength, but reflects a part of the incident light and transmits the rest, for example, a conventionally known light reflecting sheet or this light. Carbon powder is dispersed in the diffusion sheet.

  In the present invention, a part of the projection light from the projector 50 is reflected by the front projection screen 90, so that the passenger in the rear seat 102 views the image displayed on the front projection screen 90. Can do. On the other hand, the remaining projection light from the projector 50 is transmitted through the front projection screen 90, but is absorbed by the reflection sheet 40 of the rearview mirror 104, so that it does not reach the driver, and other external light components Since the light reaches the driver, the driver can check the rear field of view through the room mirror 104 without being obscured by the projector image (projected light from the projector 50).

It is sectional drawing which shows the structure of the front projection type screen which concerns on this invention. It is sectional drawing which shows the structure of the reflective sheet used by this invention. It is a conceptual diagram of the reflection characteristic and the transmission characteristic of the optical multilayer film used in the present invention. It is a structural example of the reflective sheet used by this invention. It is a figure which shows the reflective characteristic of the reflective sheet of FIG. It is a figure which shows the permeation | transmission characteristic of the reflective sheet of FIG. It is a surface external view (1) of the light-diffusion sheet used by this invention. It is a surface external view (2) of the light-diffusion sheet used by this invention. It is a modification (1) of the front projection type screen which concerns on this invention. It is a modification (2) of the front projection type screen which concerns on this invention. It is sectional drawing which shows the structural example of the vehicle-mounted projector system which concerns on this invention. It is an application example (1) of the vehicle-mounted projector system of FIG. It is an application example (2) of the vehicle-mounted projector system of FIG. It is an example of composition of a reflective sheet provided in a back mirror. It is a figure which shows the reflective characteristic of the reflective sheet of FIG. It is sectional drawing which shows the other structural example of the vehicle-mounted projector system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reflection sheet, 3 ... Light diffusion sheet, 3a ... Area | region, 4 ... Semi-absorption filter, 5 ... Polarization filter, 10, 20, 30, 90 ... Front projection type screen, 11, 41 ... Substrate, 12 ... Optical multilayer film , 12H ... High refractive index film, 12L ... Low refractive index film, 42 ... Reflective layer, 43 ... Metal oxide film, 44 ... Light absorbing thin film, 101 ... Driver's seat, 102 ... Rear seat, 103 ... Rear window glass, 104 …rearview mirror

Claims (8)

It consists of a plurality of layers in which several kinds of optical films with different refractive indexes are laminated, has a high reflection characteristic for light in a specific wavelength region including the wavelength region of projection light, and has a wavelength region other than the specific wavelength region. An optical multilayer film having a high light transmission characteristic; and a light diffusion layer provided on the optical multilayer film and scatters and radiates reflected light from the optical multilayer film. A front projection screen that reflects the projection light from the surface side and displays it as an image,
The light diffusion layer has a region A that allows incident light from the front surface side of the screen to pass or transmit to the optical multilayer film side of the back surface without changing its optical characteristics,
External light from the front side of the screen passes through or passes through the area A of the light diffusion layer, and further passes through the optical multilayer film so that the scenery on the front side of the screen can be viewed from the back side of the screen. A front projection screen characterized in that it enables.   The front projection screen according to claim 1, wherein the region A is a plurality of holes penetrating the light diffusion layer.   The front projection screen according to claim 1, further comprising a semi-absorbing plate that is provided on a surface opposite to the light diffusion layer of the optical multilayer film and absorbs part of external light.   The front projection screen according to claim 1, further comprising a polarizing plate that is provided on a surface opposite to the light diffusion layer of the optical multilayer film and absorbs part of external light. An in-vehicle projector system comprising a front projection screen according to any one of claims 1 to 4 and a projector that serves as a light source for the projection light, and is mounted on an automobile having a driver seat and a rear seat. And
The in-vehicle projector system, wherein the front projection screen is provided behind the driver seat and in front of the rear seat, and the projector is provided closer to the rear seat than the front projection screen.   The in-vehicle projector system according to claim 5, further comprising a selective reflection filter that reflects light in the specific wavelength region on a rear window of the motor vehicle.   The in-vehicle projector system according to claim 5, further comprising a selective reflection filter that absorbs light in the specific wavelength region and reflects light outside the specific wavelength region in a rearview mirror of the motor vehicle. A motor vehicle that includes a front projection screen that reflects a part of incident light and transmits the remaining light, and a projector that projects light of a specific wavelength region onto the front projection screen, and has a driver seat and a rear seat. An in-vehicle projector system,
The front projection screen is provided behind the driver seat and in front of the rear seat, and the projector is provided on the rear seat side of the front projection screen.
An in-vehicle projector system comprising a selective reflection filter that absorbs light in the specific wavelength region and reflects light outside the specific wavelength region in a rearview mirror of the motor vehicle.

Images