JP2011064851A - Reflection screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection screen which views high-contrast images even in the presence of outside light. <P>SOLUTION: The reflection screen 100 reflects projection light Lp obliquely projected toward an observation surface 100a of a screen substrate 10 from a direction shifted in the vertical direction in relation to the normal line of the observation surface 100a toward the observation surface 100a. A plurality of recessed portions 11 or projecting portions is formed in the vertical or lateral direction of the screen substrate 10. The recessed portion 11 or the projecting portion includes a projection light reflection surface 12 reflecting the projection light Lp and an outside light absorbing surface 13 absorbing the outside light Lo. The surface roughness of the projection light reflection surface 12 is smoother than that of the outside light absorbing surface 13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reflective screen that is used with incident projection light.

  A reflection screen that receives projection light emitted from a projector or the like and reflects the projection light to display an enlarged image is known. Among them, as a reflective screen for a proximity projector, a plurality of convex portions are formed on the observation surface of the screen substrate, a reflecting surface that reflects projection light at the unit shape portion of the convex portion, and light absorption that absorbs external light A reflective screen provided with a layer is known (see Patent Document 1).

JP 2006-215162 A

  However, since the reflection screen for a proximity projector is used in the presence of outside light such as indoor lighting, there is a demand for a reflection screen that displays an image with higher contrast even in the presence of outside light. Yes.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] The reflection screen according to this application example uses projection light projected obliquely toward the observation surface from a direction shifted in a direction perpendicular to the normal line of the observation surface of the screen substrate. A plurality of recesses or projections formed in a vertical direction and a horizontal direction of the screen substrate, wherein the recesses or projections reflect a projection light reflecting surface that reflects projection light, and external light. An external light absorbing surface that absorbs, and the projection light reflecting surface is smoother than the surface roughness of the external light absorbing surface.

According to this configuration, the surface roughness of the projection light reflection surface is smoother than the surface roughness of the external light absorption surface in the reflection screen. In other words, the surface roughness of the external light absorbing surface is made larger than the surface roughness of the projection light reflecting surface.
In this way, the projection light can be reflected by the smooth surface of the projection light reflecting surface, and the outside light can be sufficiently absorbed by the rough surface of the outside light absorbing surface, and even in the presence of outside light such as indoor lighting, A reflective screen that projects an image with high contrast can be obtained.

  Application Example 2 In the reflective screen according to the application example described above, it is desirable that the external light absorbing surface has a surface roughness Ra of 82 nm or more and 5000 nm or less.

  According to this configuration, since the surface roughness Ra of the external light absorption surface is 82 nm or more and 5000 nm or less, the surface of the external light absorption surface is rough, so that light can be efficiently absorbed.

  Application Example 3 In the reflection screen according to the application example described above, it is desirable that the projection light reflecting surface has a surface roughness Ra of 10 nm or more and 274 nm or less.

  According to this configuration, since the surface roughness Ra of the projection light reflecting surface is 10 nm or more and 274 nm or less, the surface of the projection light reflecting surface is smooth and the projection light can be efficiently reflected.

  Application Example 4 In the reflection screen according to the application example, it is preferable that the projection light reflecting surface is a curved surface.

  According to this configuration, since the projection light reflection surface is a curved surface, the projection light from a light source such as a projector can be efficiently reflected to the observation surface side of the reflection screen.

Sectional drawing which shows the positional relationship of the reflective screen concerning this embodiment, and a light source. The front view of the reflective screen in this embodiment. The A section enlarged view of Drawing 2 showing the shape of the crevice formed in the screen substrate in this embodiment. The schematic sectional drawing which shows the cross section of the perpendicular direction of the reflective screen in this embodiment. The graph which shows the relationship between a blast particle and the reflectance of light. The graph which shows the relationship between the blast particle | grains and light reflectance when forming an Al (aluminum) film | membrane on the surface which carried out the sandblasting process. The table | surface which shows the relationship between blast particle | grains and the processed surface roughness. The schematic process drawing which shows the manufacturing method of the reflective screen in this embodiment. The schematic process drawing which shows the manufacturing method of the reflective screen in this embodiment. The schematic process drawing which shows the manufacturing method of the other reflective screen in this embodiment. The schematic process drawing which shows the manufacturing method of the other reflective screen in this embodiment. The schematic process drawing which shows the manufacturing method of the other reflective screen in this embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. In the drawings used for the following description, the ratio of dimensions of each member is appropriately changed so that each member has a recognizable size. Moreover, in the following description, a rectangular coordinate system is set and the positional relationship of each member is demonstrated. A predetermined direction in the vertical plane is defined as an X-axis direction, a direction orthogonal to the X-axis direction in the vertical plane is defined as a Y-axis direction, and a direction orthogonal to the X-axis direction and the Y-axis direction is defined as a Z-axis direction.
(Embodiment)

<Configuration of reflection screen>
FIG. 1 is a cross-sectional view showing the positional relationship between a reflective screen and a light source according to this embodiment. FIG. 2 is a front view of the reflection screen in the present embodiment.
As shown in FIGS. 1 and 2, the reflective screen 100 is a light source arranged at a position shifted in the vertical direction (Y-axis direction) with respect to the normal NL passing through the center point C of the observation surface 100 a of the reflective screen 100. The projection light Lp projected obliquely from P toward the observation surface 100a is reflected to the observation surface side (Z-axis positive direction side) of the reflection screen 100. In the reflective screen 100, the normal line NL is arranged in parallel with the Z axis.
The screen substrate 10 is formed using a resin such as polyvinyl chloride (PVC) and has flexibility. Further, the screen substrate 10 is colored with a black light absorbing material as a whole, for example, by staining or the like, and is formed so as to be able to absorb visible light.

The reflective screen 100 is provided with a plurality of concave portions on the observation surface 100 a side of the screen substrate 10.
FIG. 3 shows the shape of the recess formed in the screen substrate, and is an enlarged view of part A in FIG. 4 is a cross-sectional view showing a vertical cross section of the reflective screen, and is a schematic cross-sectional view taken along the line BB in FIG.

Concave portions 11 are arranged on the screen substrate 10 so as to be in contact with each other in a lattice shape. The diameter of the hemisphere of the recess 11 is, for example, about 20 μm to 200 μm.
As shown in FIGS. 3 and 4, the recess 11 includes a projection light reflecting surface 12 that is hemispherical and reflects projection light, and an external light absorbing surface 13 that absorbs external light.
In order to reflect the projection light efficiently on the projection light reflection surface 12, a reflection film 16 is formed on at least a part of the projection light reflection surface 12 with a reflective material such as aluminum (Al). The reflective film 16 is formed by a sputtering method or a vapor deposition method so as to have a film thickness of 10 nm to 5 μm.

An external light absorption surface 13 is formed in a portion where external light such as illumination light is incident, except for the projection light reflection surface 12 of the recess 11.
The external light absorbing surface 13 can absorb light by making the base material of the screen substrate 10 black, or by applying a light absorbing material such as black carbon powder to the inner wall surface of the recess 11. It is configured.

Further, the surface roughness Ra of the projection light reflecting surface 12 is smoother than the surface roughness Ra of the external light absorbing surface 13 in the screen substrate 10. In other words, the surface roughness Ra of the external light absorbing surface 13 is made larger than the surface roughness Ra of the projection light reflecting surface 12.
For example, the surface roughness Ra of the external light absorbing surface 13 is formed to be 82 nm or more and 5000 nm or less, and the surface roughness Ra of the projection light reflecting surface 12 is formed to be 10 nm or more and 274 nm or less.
In addition, surface roughness Ra means centerline average roughness in this application.

Further, although not shown, a protective layer may be formed on the observation surface of the screen substrate 10 so as to fill the recess 11. The protective layer can be formed of, for example, a flexible material such as a resin.
An antireflection film may be formed on the outermost surface of the screen substrate 10 on the observation surface side on the protective layer. The antireflection film is preferably formed of the same material as that of the protective layer, and the refractive index is adjusted between the protective layer and the protective layer so as to prevent reflection of projection light or external light on the surface of the protective layer. .

<Relationship between surface roughness and light reflectance>
Next, the relationship between the surface roughness of the recess and the light reflectance will be considered.
Here, sandblasting is performed on a glass substrate using abrasives having different particle diameters, and the surface is transferred to a polyvinyl chloride (PVC) sheet, which is the material of the screen substrate. The relationship was investigated.
As the type of abrasive, WA (white alumina abrasive) was used. As the level of abrasives as blast particles, investigation was performed with 6 types of counts of WA # 600, WA # 800, WA # 1000, WA # 2000, WA # 3000, WA # 4000, and sandblasting We also investigated the level of none.

  FIG. 5 is a graph showing the relationship between blast particles and light reflectance. FIG. 6 is a graph showing the relationship between blast particles and light reflectance when an Al (aluminum) film is formed on the sandblasted surface. FIG. 7 is a table showing the relationship between blast particles and processed surface roughness.

As shown in FIG. 5, those processed using WA # 600, WA # 800, WA # 1000, and WA # 2000 as blast particles have a light reflectance of 0.5% or less, and light reflection is low. I understand that it is small. The surface roughness Ra of the screen substrate at this time is 1148 nm to 274 nm from FIG.
The reflectivity increases as the blast particles WA # 3000, WA # 4000, and the abrasive particles become finer. The processed surface using WA # 3000 has a reflectance of about 0.8% and the surface roughness Ra is 82 nm, and the processed surface using WA # 4000 has a reflectance of about 2.5% and the surface roughness Ra is 33 nm.

In addition, the transfer surface of the screen substrate that is not subjected to sandblasting is transferred with the surface state of the transfer mold in the reflection screen manufacturing method described later, and a smooth surface is obtained. In this plane, the reflectance of light is about 4.2%, and the surface roughness Ra is 36 nm.
Thus, as the abrasive becomes rougher, the reflectance of light on the processed surface decreases, and when the surface roughness Ra that is the processed surface of WA # 2000 is 274 nm or less, the reflectance is in an equilibrium state.

  If a surface with low light reflectance is used as an external light absorbing surface, light is sufficiently absorbed. For example, if the reflectance of light is 1.0% or less, the surface may be processed using an abrasive coarser than WA # 3000. As surface roughness Ra, it is 82 nm or more, and 5000 nm or less which is the surface roughness of ground glass is preferable.

Next, as shown in FIG. 6, when an Al film is formed on the transfer surface that has been sandblasted, the light reflectance is significantly improved.
Those processed using WA # 600, WA # 800, WA # 1000, and WA # 2000 as blast particles have a light reflectance of 10% or less, indicating that the light reflection is small. The surface roughness Ra of the screen substrate at this time is 1148 nm to 274 nm from FIG.
The reflectivity increases as the blast particles WA # 3000, WA # 4000, and the abrasive particles become finer. The processed surface using WA # 3000 has a reflectance of about 14% and the surface roughness Ra is 82 nm. The processed surface using WA # 4000 has a reflectance of about 32% and the surface roughness Ra is 33 nm.

On the transfer surface of the screen substrate not subjected to sandblasting, the light reflectance is about 86% and the surface roughness Ra is 36 nm.
Thus, as the abrasive particles become finer, the reflectance of light on the processed surface is improved, and between WA # 2000 (surface roughness Ra is 274 nm) and WA # 3000 (surface roughness Ra is 82 nm). It is considered that there is a critical point for improving the reflectance.

If a surface having a high light reflectance is used as the projection light reflecting surface, the light is sufficiently reflected. For example, the surface may be processed using an abrasive finer than WA # 2000 as the projection light reflecting surface. The surface roughness Ra at this time is 274 nm or less, and preferably 10 nm or more, which is the surface roughness of the polished surface of the glass.
More preferably, the surface roughness Ra which is the processed surface of WA # 3000 is 82 nm or less, and the surface roughness of the polished surface of the glass is 10 nm or more.

<Action of reflection screen>
Next, the operation of the reflective screen will be described.
As described with reference to FIG. 1, observation is performed from a light source P such as a projector disposed at a position shifted in the vertical direction (Y-axis direction) with respect to the normal NL passing through the center point C of the observation surface 100 a of the reflection screen 100. The projection light Lp is projected obliquely toward the surface 100a, and an image is projected on the reflection screen 100.

  Such projection light Lp incident obliquely with respect to the observation surface 100a is incident on the projection light reflection surface 12 formed in the recess 11 as shown in FIG. A reflection film 16 is formed on a part of the projection light reflection surface 12, and the reflection light Lr is reflected from the projection light Lp on the observation side of the reflection screen 100. The projection light Lp is blocked by the edge of the recess 11 and the projection light Lp does not enter the entire surface of the projection light reflecting surface 12.

  On the other hand, outside light Lo enters the observation surface of the reflection screen 100 from above the reflection screen 100 in addition to the projection light Lp. The external light Lo incident on the observation surface is incident on the external light absorption surface 13 of the recess 11. The external light Lo that has reached the external light absorption surface 13 of the recess 11 is absorbed by the external light absorption surface 13. The external light is blocked by the edge of the recess 11 and does not enter the projection light reflecting surface 12.

In the reflective screen 100 of the present embodiment, the surface roughness of the projection light reflecting surface 12 is smoother than the surface roughness of the external light absorbing surface 13 in the recess 11. In other words, the surface roughness of the external light absorbing surface 13 is formed to be rougher than the surface roughness of the projection light reflecting surface 12.
For this reason, the projection light Lp is reflected by the smooth surface of the projection light reflecting surface 12, the outside light Lo can be sufficiently absorbed by the rough surface of the outside light absorbing surface 13, and the outside light Lo such as indoor lighting is present. However, it is possible to obtain the reflective screen 100 that displays an image with high contrast.

<Manufacturing method 1 of a reflective screen>
Next, an example of a manufacturing method of the reflection screen having the above configuration will be described.
8 and 9 are schematic process diagrams showing a manufacturing method of the reflective screen.
As shown in FIG. 8A, a mask 21 is formed on a glass substrate 20 such as soda glass. The mask 21 has a chromium oxide (CrO) film as a base and a chromium (Cr) film formed thereon by a sputtering method or the like. Note that before the mask 21 is formed, the surface of the glass substrate 20 may be sandblasted to form a rough surface of the glass substrate 20 to improve the adhesion of the mask 21.
Then, an opening 22 of about several μm is formed at a position where a concave portion is formed with respect to the mask 21. The opening 22 is formed using photoetching or laser processing.

Next, as shown in FIG. 8B, the glass substrate 20 having the opening 22 formed in the mask 21 is immersed in an etching solution for a predetermined time to form a hemispherical hemispherical recess 23 in the glass substrate 20. To do. The glass substrate 20 is isotropically etched through the opening 22 by the etching solution, and the cross-sectional shape is etched into a substantially hemispherical shape.
As the etchant, an ammonium hydrogen difluoride-based etchant is used.
Subsequently, the mask 21 is peeled from the glass substrate 20. Then, as shown in FIG. 8C, a protective film 24 such as an Al film is formed on a part of the hemispherical recess 23 by vapor deposition or sputtering from an oblique direction of the glass substrate 20.

Next, as shown in FIG. 9A, the inside of the hemispherical recess 23 is blasted using a sandblasting device 25. As the blast particles, for example, an abrasive of WA # 1000 is used. Since the protective film 24 is formed in a part of the hemispherical recess 23, the portion where the protective film 24 is not formed is blasted to roughen the surface.
When the protective film 24 formed by vapor deposition or sputtering cannot withstand sandblasting, the protective film 24 may be plated to increase the thickness of the protective film 24.
And the protective film 24 is peeled from the glass substrate 20, and the glass substrate 20 is completed as an original transfer type | mold.

Next, as shown in FIG. 9B, the electroforming mold 28 is made of a metal material such as nickel (Ni) using the glass substrate 20 as the original transfer mold.
Subsequently, as shown in FIG. 9C, the shape of the electroforming mold 28 is transferred to the screen substrate 10 such as a polyvinyl chloride (PVC) sheet by applying heat and pressure. In this way, the concave portion 11 is formed in the screen substrate 10, and the concave portion 11 is provided with the external light absorbing surface 13 having a rough surface and the projection light reflecting surface 12 having a smooth surface.
Here, the screen substrate 10 is a black polyvinyl chloride (PVC) sheet containing a light absorbing material.

  Then, as shown in FIG. 9D, a reflective film 16 such as an aluminum (Al) film is formed on the projection light reflecting surface 12 of the recess 11. The reflective film 16 can be formed on the projection light reflecting surface 12 of the recess 11 by vapor deposition or sputtering from the oblique direction of the screen substrate 10. Note that a reflective film may be formed by spraying the reflective material onto the concave portion 11.

In this way, a reflective screen is manufactured. Further, a protective layer is formed of a flexible material such as a resin so as to fill the concave portion 11 of the screen substrate 10, and an antireflection film is formed thereon. You may do it.
Further, in the above-described reflection screen manufacturing method, the electroforming mold is formed using the glass substrate 20 as the original transfer mold. However, a resin mold is formed by resin transfer using the glass substrate 20, and the resin mold is photocured. The shape may be transferred to a polyethylene terephthalate sheet (PET sheet) or a polyvinyl chloride (PVC) sheet by a 2P transfer method using a conductive resin.

<Manufacturing method 2 of a reflective screen>
This manufacturing method is different from the manufacturing process described above with reference to FIG. Therefore, the process after FIG. 8 is demonstrated.
FIG. 10 is a schematic process diagram showing another method for manufacturing a reflective screen.
A protective film 24 such as an Al film is formed on a part of the hemispherical recess 23 on the glass substrate 20 obtained in FIG. Note that a dense plating layer may be provided on the protective film 24.
Using this glass substrate 20, as shown in FIG. 10A, an electroforming mold 31 is manufactured using a metal material such as nickel (Ni). Then, as shown in FIG. 10B, the electroforming mold 31 is peeled from the glass substrate 20. The electroforming mold 31 is manufactured by porous (porous) electroforming, so that the surface of the electroforming mold 31 has irregularities except for the portion where the protective film 24 is provided.

Subsequently, as shown in FIG. 10C, the shape of the electroforming mold 31 is transferred to the screen substrate 110 such as a polyvinyl chloride (PVC) sheet by applying heat and pressure. Thus, the recess 111 is formed in the screen substrate 110, and the recess 111 is provided with the external light absorbing surface 113 having a rough surface and the projection light reflecting surface 112 having a smooth surface.
Here, the screen substrate 110 is a black polyvinyl chloride (PVC) sheet containing a light absorbing material.

  Then, as shown in FIG. 10D, a reflective film 116 such as an aluminum (Al) film is formed on the projection light reflecting surface 112 of the recess 111. The reflective film 116 can be deposited on the projection light reflecting surface 112 of the recess 111 by vapor deposition or sputtering from the oblique direction of the screen substrate 110. Note that the reflective film may be formed by spraying the reflective material onto the concave portion 111.

  In this way, the reflective screen is manufactured. Further, a protective layer is formed of a flexible material such as resin so as to fill the concave portion 111 of the screen substrate 110, and an antireflection film is formed thereon. You may do it.

<Manufacturing method 3 of a reflective screen>
The reflection screen manufacturing methods 1 and 2 are manufacturing methods in which a forming die is roughened and the die is transferred to a screen substrate. Next, a manufacturing method in which the reflecting screen is roughened will be described.
11 and 12 are schematic process diagrams showing another method for manufacturing a reflective screen.
As shown in FIG. 11A, a mask 21 is formed on the glass substrate 20. Then, an opening 22 of about several μm is formed at a position where a concave portion is formed with respect to the mask 21. The opening 22 is formed using photoetching or laser processing.
Next, as shown in FIG. 11B, the glass substrate 20 having the opening 22 formed in the mask 21 is immersed in an etching solution for a predetermined time to form a hemispherical hemispherical recess 23 in the glass substrate 20. To do. The glass substrate 20 is isotropically etched through the opening 22 by the etching solution, and the cross-sectional shape is etched into a substantially hemispherical shape.
Subsequently, the mask 21 is peeled from the glass substrate 20. And as shown in FIG.11 (c), the electroforming mold 32 is manufactured with metal materials, such as nickel (Ni), using the glass substrate 20 as an original transfer type | mold.
Subsequently, as shown in FIG. 11D, the shape of the electroforming mold 32 is transferred to a screen substrate 120 such as a polyvinyl chloride (PVC) sheet by applying heat and pressure. Here, the screen substrate 120 is a black polyvinyl chloride (PVC) sheet containing a light absorbing material.

Then, as shown in FIG. 12A, a protective film 124 such as an aluminum (Al) film is formed on a part of the recess 121 by vapor deposition or sputtering from an oblique direction of the screen substrate 120.
Next, as shown in FIG. 12 (b), the inside of the recess 121 is blasted using a sand blast device 25. As the blast particles, for example, an abrasive of WA # 1000 is used. Since the protective film 124 is formed in a part of the recess 121, the portion where the protective film 124 is not formed is blasted to roughen the surface.

Then, the protective film 124 is peeled off, and a reflective film 126 such as an aluminum (Al) film is formed on the projection light reflecting surface 122 of the recess 121 as shown in FIG. The reflective film 126 can be deposited on the projection light reflecting surface 122 of the recess 121 by vapor deposition or sputtering from the oblique direction of the screen substrate 120. Note that the reflective film may be formed by spraying the reflective material onto the concave portion 121.
Thus, the recess 121 is formed in the screen substrate 120, and the recess 121 is provided with the external light absorbing surface 123 having a rough surface and the projection light reflecting surface 122 having a smooth surface.

  Further, as another manufacturing method, using the screen substrate 120 to which the shape of the electroforming mold 32 shown in FIG. 11D is transferred, an acrylic paint or the like is applied to a part of the recess 121 to smooth the surface. Can be. A reflective film may be formed on the surface to which this paint is applied to form a projection light reflecting surface.

  As described above, in the above embodiment, the projection light reflection surface that reflects the projection light and the external light absorption surface that absorbs the external light are provided in the concave portion, but the projection light reflection surface that reflects the projection light on the convex portion, It is good also as a structure which provides the external light absorption surface which absorbs external light. In the above embodiment, the external light absorbing surface is formed as a curved surface, but may be a flat surface other than the curved surface.

  DESCRIPTION OF SYMBOLS 10 ... Screen substrate, 11 ... Recessed part, 12 ... Projection light reflecting surface, 13 ... External light absorbing surface, 16 ... Reflecting film, 20 ... Glass substrate, 21 ... Mask, 22 ... Opening, 23 ... Hemispherical recessed part, 24 ... Protection Membrane, 25 ... Sandblasting device, 28 ... Electric mold, 31, 32 ... Electric mold, 100 ... Reflective screen, 100a ... Observation surface, 110 ... Screen substrate, 111 ... Recess, 112 ... Projection light reflection surface, 113 ... Absorption of external light Surface 116, reflective film 120, screen substrate 121, concave portion 122, projection light reflection surface 123, external light absorption surface 124, protective film 126, reflection film, Lo external light, Lp projection light, Lr: reflected light, P: light source.

Claims (4)

A reflective screen that reflects the projection light projected obliquely toward the observation surface from a direction perpendicular to the normal of the observation surface of the screen substrate, to the observation surface side;
A plurality of concave or convex portions are formed in the vertical direction and horizontal direction of the screen substrate,
The concave portion or the convex portion includes a projection light reflecting surface that reflects projection light, and an external light absorbing surface that absorbs external light,
The reflective screen is characterized in that the surface roughness of the projection light reflecting surface is smoother than the surface roughness of the external light absorbing surface. The reflective screen according to claim 1.
The reflection screen, wherein the external light absorbing surface has a surface roughness Ra of 82 nm or more and 5000 nm or less. The reflective screen according to claim 1.
The reflection screen, wherein the projection light reflecting surface has a surface roughness Ra of 10 nm or more and 274 nm or less. The reflective screen according to any one of claims 1 to 3,
The reflection screen, wherein the projection light reflection surface is a curved surface.

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