JP2006259642A - Light diffusion substrate, method for manufacturing light diffusion substrate, transmission screen and rear type projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light diffusion substrate which suitably diffuses light and is inexpensively manufactured, and also to provide a method for manufacturing the light diffusion substrate, a transmission screen having the light diffusion substrate, and a rear type projector having the transmission screen. <P>SOLUTION: The light diffusion substrate 7 is provided to the transmission screen 330 having: a Fresnel lens substrate 210 on the surface on the side of a light emitting surface of which a Fresnel lens 211 is formed; and a micro lens substrate 1 arranged on the side of the light emitting surface of the Fresnel lens substrate 210 and on which a plurality of micro lenses 8 are formed. Irregularity 72 with surface roughness (ten-point average roughness specified in JIS B 0601) of ≤0.3 μm is provided on the surface 71 of the light diffusion substrate 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light diffusing substrate, a method for manufacturing the light diffusing substrate, a transmissive screen, and a rear projector.

In recent years, the demand for rear type projectors (projectors) is increasing as a display suitable for home theater monitors, large-screen televisions, and the like. As a transmissive screen used in the rear projector, those having a lenticular lens are disclosed in, for example, Patent Document 1, Patent Document 2, and Patent Document 3.
The transmissive screen described in Patent Document 1 includes a lenticular lens substrate (a lenticular sheet lens supported on a transparent support) and a light diffusion layer (diffusion layer) provided on the light emission side of the lenticular lens substrate. ) And a light shielding layer (black stripe) provided between the lenticular lens substrate and the light diffusion layer. Such a transmissive screen is configured to shield outside light (for example, sunlight or electric illumination light) incident on the transmissive screen by a light shielding layer. Thereby, the light emitted from the lenticular lens substrate or the light diffusion layer can be suitably diffused, that is, the contrast can be improved.

  However, the transmissive screen of Patent Document 1 has a problem in that when the transmissive screen is manufactured, a process of providing a light shielding layer is essential, and thus the manufacturing cost increases. Further, in this transmissive screen, when the position accuracy of the light shielding layer with respect to the lenticular lens substrate is insufficient, it becomes difficult to reliably shield the external light, and thus the light from the lenticular lens substrate is sufficiently absorbed. There was a problem that (preferably) it was difficult to diffuse.

  The transmission screen described in Patent Document 2 includes a lenticular lens substrate and a light absorption layer (light-shielding portion) provided on the lenticular lens substrate. Such a transmission screen is configured to absorb (light-shield) external light incident on the transmission screen by a light absorption layer (colored layer). Thereby, the light emitted from the lenticular lens substrate can be suitably diffused.

However, the transmissive screen of Patent Document 2 has a problem in that when the transmissive screen is manufactured, a process of providing a light absorption layer is essential, and thus the manufacturing cost is increased.
The transmissive screen described in Patent Document 3 includes a Fresnel lens substrate (Fresnel lens sheet) and a lenticular lens substrate provided on the light emission side of the Fresnel lens substrate. Fine irregularities are formed on the lens convex surface of the lenticular lens substrate. Thereby, the light emitted from the lenticular lens substrate can be suitably diffused.
However, the transmissive screen of Patent Document 3 has a problem in that when the transmissive screen is manufactured, an advanced technique for forming the fine unevenness is required, which increases the manufacturing cost. Further, when the formation of the fine irregularities is insufficient, there is a problem that it becomes difficult to suitably diffuse light from the lenticular lens substrate.

Japanese Patent Laid-Open No. 10-301208 JP-A-5-34829 JP-A-5-313252

  An object of the present invention is to provide a light diffusing substrate capable of suitably diffusing light and to be manufactured at low cost, to provide a method for manufacturing the light diffusing substrate, and to transmit with the light diffusing substrate. An object of the present invention is to provide a type screen and to provide a rear type projector provided with the transmission type screen.

Such an object is achieved by the present invention described below.
The light diffusion substrate of the present invention includes a Fresnel lens substrate in which a Fresnel lens is formed on the light exit surface side surface, and a lens substrate that is disposed on the exit surface side of the Fresnel lens substrate and on which a plurality of lenses are formed. A light diffusing substrate provided on a transmissive screen,
At least one of the surfaces is provided with irregularities having a surface roughness Rz (ten-point average roughness specified in JIS B 0601) of 0.3 μm or less.
Thereby, the light-diffusion board | substrate which can diffuse light suitably and can be manufactured cheaply can be provided.

In the light diffusing substrate of the present invention, it is preferable that the average pitch of the convex portions in the unevenness of the light diffusing substrate is 1 μm or less.
Thereby, light can be more suitably diffused.
In the light diffusing substrate of the present invention, it is preferable that the average pitch of the convex portions in the unevenness of the light diffusing substrate is 0.1 to 5.0% of the average diameter of the lenses of the lens substrate.
Thereby, light can be more suitably diffused.

In the light diffusing substrate of the present invention, the average thickness of the light diffusing substrate is preferably 1.0 to 5.0 mm.
Thereby, generation | occurrence | production of a diffracted light and a moire can be prevented and suppressed more effectively.
The light diffusing substrate manufacturing method of the present invention is a method of manufacturing the light diffusing substrate of the present invention,
By pressing a mold having a surface with irregularities on one surface of the original plate to be the light diffusion substrate, the irregular shape of the mold is transferred to one surface of the original plate to obtain the light diffusion substrate. It is characterized by that.
Thereby, it is possible to manufacture (provide) a light diffusing substrate that can diffuse light appropriately and can be manufactured at low cost.

In the method for manufacturing a light diffusing substrate of the present invention, the unevenness of the mold is preferably formed by a blast method.
Thereby, the rough surface processing can be performed on the mold at low cost, that is, the mold can be manufactured at low cost.
In the light diffusing substrate manufacturing method of the present invention, the blasting method is preferably a wet blasting method.
Thereby, the rough surface processing can be performed on the mold at a low cost, that is, the mold can be manufactured at a low cost.

In the method for producing a light diffusion substrate of the present invention, it is preferable that the average particle size of the colliding particles is 10 μm or less.
Thereby, the rough surface processing can be performed on the mold at a lower cost, that is, the mold can be manufactured at a lower cost.
The transmission screen of the present invention includes a Fresnel lens substrate having a Fresnel lens formed on the light exit surface side surface, a lens substrate disposed on the exit surface side of the Fresnel lens substrate and having a plurality of lenses formed thereon, And a light diffusion substrate according to the invention.
Thereby, the light-diffusion board | substrate which can diffuse light suitably and can be manufactured cheaply can be manufactured.

In the transmissive screen of the present invention, the lens substrate is preferably a microlens substrate.
Thereby, the transmission screen can have a suitable viewing angle distribution, and the occurrence of moire can be suppressed.
In the transmission screen according to the aspect of the invention, it is preferable that the light diffusion substrate is disposed between the Fresnel lens substrate and the lens substrate.
Thereby, the transmission screen can have a suitable viewing angle distribution, and the occurrence of moire can be suppressed.

In the transmissive screen according to the aspect of the invention, it is preferable that the unevenness of the light diffusing substrate is provided on one surface of the light diffusing substrate, and the surface is opposed to the lens substrate.
Thereby, it is possible to improve luminance by preventing / suppressing a decrease in transmittance.
In the transmissive screen according to the aspect of the invention, it is preferable that the unevenness of the light diffusing substrate is provided on one surface of the light diffusing substrate, and the surface is opposed to the Fresnel lens substrate.
Thereby, it is possible to improve luminance by preventing / suppressing a decrease in transmittance.

In the transmissive screen of the present invention, it is preferable that the unevenness of the light diffusing substrate is provided on both surfaces of the light diffusing substrate.
Thereby, the luminance can be improved by further preventing and suppressing the decrease in transmittance.
In the transmissive screen according to the aspect of the invention, it is preferable that the light diffusing substrate is disposed on an exit surface side of the lens substrate.
Thereby, light can be more suitably diffused.

In the transmissive screen of the present invention, it is preferable that the unevenness of the light diffusing substrate is provided on one surface of the light diffusing substrate, and the other surface faces the lens substrate.
Thereby, light can be more suitably diffused.
In the transmissive screen according to the aspect of the invention, it is preferable that the unevenness of the light diffusing substrate is provided on one surface of the light diffusing substrate, and the surface is opposed to the lens substrate.
Thereby, it is possible to improve luminance by preventing / suppressing a decrease in transmittance.

In the transmissive screen of the present invention, it is preferable that the unevenness of the light diffusing substrate is provided on both surfaces of the light diffusing substrate.
Thereby, the luminance can be improved by further preventing and suppressing the decrease in transmittance.
In the transmissive screen of the present invention, it is preferable that the lens of the lens substrate is provided on the Fresnel lens substrate side.
Thereby, the transmission screen can have a suitable viewing angle distribution, and the occurrence of moire can be suppressed.
A rear projector according to the present invention includes the transmission screen according to the present invention.
Accordingly, it is possible to provide a rear projector that can diffuse light appropriately and can be manufactured at low cost.

Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
<First Embodiment>
FIG. 1 is a longitudinal sectional view schematically showing a first embodiment of an optical system of a transmissive screen according to the present invention, FIG. 2 is an exploded perspective view of the transmissive screen shown in FIG. 1, and FIG. FIG. 4 is a longitudinal sectional view schematically showing a process of manufacturing a light diffusion substrate using the mold shown in FIG. 3, and FIG. 5 is a rear type projector of the present invention. It is a figure shown typically. 1 and 4 are diagrams schematically showing the light diffusion substrate, and do not reflect actual dimensions (the same applies to FIGS. 6 to 8, 10 and 11 described later). That is, the unevenness with respect to the light diffusion substrate is shown to be larger than the actual size.

A transmissive screen 330 shown in FIG. 1 includes a Fresnel lens substrate 210, a microlens substrate (lens substrate) 1, and a light diffusion substrate 7. Hereinafter, the configuration of each unit will be described.
The Fresnel lens substrate 210 has a plurality of Fresnel lenses 211 formed on the light exit surface side surface. These Fresnel lenses 211 are preferably arranged (arranged) regularly along the surface direction of the Fresnel lens substrate 210 (vertical direction and horizontal direction in FIG. 2).

As shown in FIGS. 1 and 2, in the transmissive screen 330, the microlens substrate 1 is disposed to face the exit surface side of the Fresnel lens substrate 210, that is, the surface side on which the Fresnel lens 211 is formed. Yes.
The microlens substrate 1 has a plurality of microlenses (lenses) 8 formed on the light incident surface side surface, that is, the Fresnel lens substrate 210 side surface. Since the microlens 8 is provided (positioned) on the Fresnel lens substrate 210 side in this way, the microlens substrate 1 (transmission type screen 330) can have a suitable viewing angle distribution, and moire can be reduced. Occurrence can be prevented or suppressed.
These microlenses 8 are preferably arranged regularly along the surface direction of the microlens substrate 1 (vertical and horizontal directions in FIG. 2).

  As shown in FIG. 2 (the same applies to FIG. 1), in the transmissive screen 330, the light diffusion substrate 7 is disposed (inserted) between the Fresnel lens substrate 210 and the microlens substrate 1. As a result, the light that has passed through the Fresnel lens 211 is once diffused by the light diffusion substrate 7 and then incident on the microlens substrate 1. As a result, the occurrence of regular interference patterns is prevented / suppressed, and the occurrence of moire in the Fresnel lens substrate 210 and the microlens substrate 1 is prevented / suppressed.

As shown in FIG. 1, on the surface 71 of the light diffusing substrate 7 facing the microlens substrate 1, minute irregularities 72 are randomly provided, that is, roughened. Further, the surface 73 of the light diffusion substrate 7 facing the Fresnel lens substrate 210 has a planar shape.
The surface 71 (unevenness 72) has a surface roughness Rz (ten-point average roughness specified in JIS B 0601) of 0.3 μm or less. Further, the surface roughness Rz is preferably 0.01 to 0.3 μm, and more preferably 0.05 to 0.1 μm.

When the surface roughness Rz satisfies the relationship as described above, light can be suitably diffused, and therefore the front luminance (gain) of the transmissive screen 330 can be increased even with a small number of light sources. Thus, the transmission screen 330 is effective for energy saving.
Further, when the surface roughness Rz satisfies the above relationship, the cost for roughing the large surface 71 used in the rear projector 300 described later can be suppressed (reduced). Therefore, the light diffusion substrate 7 can be manufactured easily and inexpensively.

The unevenness 72 of the surface 71 may be formed with, for example, a protrusion that protrudes larger than the other protrusions. For this reason, by using the ten-point average roughness for the surface roughness of the surface 71, a uniform surface roughness can be set in the surface 71.
Moreover, it is preferable that the average pitch (length shown by P in FIG. 1) of the convex portions in the concave and convex portion 72 of the light diffusion substrate 7 is 1 μm or less. When the average pitch P satisfies the above relationship, light can be diffused more suitably.

  Further, the average pitch P is preferably 0.1 to 5.0% of the average diameter of the microlenses 8 (the length indicated by φD in FIG. 1), and is 0.1 to 1.0%. Is more preferable. When the average pitch P satisfies the above relationship, light can be diffused more suitably. Further, the diffused light can be preferably incident on the microlens 8 (microlens substrate 1).

Further, the average thickness of light diffusion substrate 7 (the length indicated by t in FIG. 2) is preferably equal to or less than the thickness of Fresnel lens substrate 210 and microlens substrate 1. The value (average thickness t) is, for example, 1.0 to 5.0 mm. When the average thickness t satisfies the above relationship, the distance between the Fresnel lens substrate 210 and the microlens substrate 1 can be shortened, and ghosting due to internal diffusion, reduction in contrast, and reduction in transmittance can be prevented. It can be prevented / suppressed.
Moreover, it does not specifically limit as a constituent material (molding material) of the light-diffusion board | substrate 7, For example, various glass and plastics are mentioned.

Next, a method for manufacturing (molding) such a light diffusion substrate 7 will be described.
First, a mold 400 is manufactured (manufactured) used when the light diffusing substrate 7 is molded.
As shown in FIG. 3A, the surface (mirror surface) 402 of the original plate 401 to be the mold 400 is roughened by wet blasting (blasting). As a result, as shown in FIG. 3B, minute irregularities 403 are formed on the surface 402, and the mold 400 is obtained.

By using the wet blast method in this way, the surface 402 can be roughened at low cost (easily), that is, the mold 400 can be manufactured (obtained) at low cost.
In addition, the average particle diameter of the particles 500 that collide with the surface 402 in the wet blast method is preferably 10 μm or less, and more preferably 1 to 5 μm. As a result, the surface 402 can be roughened at a lower cost, that is, the mold 400 can be manufactured at a lower cost.

Further, the constituent material of the particles 500 is not particularly limited, and for example, it is preferably mainly composed of alumina, zirconium oxide, silicon oxide or the like.
Moreover, it does not specifically limit as a constituent material of the metal mold | die 400 (original plate 401), For example, heat resistant steel, a cemented carbide, ceramics etc. are mentioned.
Further, the surface 402 of the original plate 401 may be previously subjected to a plating process (for example, nickel electroforming).

Next, the light diffusion substrate 7 is manufactured using the mold 400.
As shown in FIG. 4A, the surface 402 of the mold 400 on which the unevenness 403 is formed is opposed to the surface 71 of the original plate 70 that becomes the light diffusion substrate 7.
Next, as shown in FIG. 4B, the surface 402 of the mold 400 is pressed against the surface 71 of the original plate 70 while heating the mold 400. Thereby, the uneven shape on the surface 402 of the mold 400 is transferred to the surface 71 of the original plate 70.

Thereafter, as shown in FIG. 4C, the light diffusing substrate 7 having the irregularities 72 formed on the surface 71 is obtained by releasing the mold.
Thus, the light diffusion substrate 7 is formed by a transfer method. Thereby, the light-diffusion board | substrate 7 can be manufactured reliably.
As described above, in the transmissive screen 330, the unevenness 72 of the light diffusion substrate 7 faces the microlens substrate 1 (see FIG. 1). Thereby, it is possible to improve luminance by preventing / suppressing a decrease in transmittance.

Hereinafter, a rear projector using the transmission screen 330 will be described.
As shown in FIG. 5, the rear projector 300 has a configuration in which a projection optical unit 310, a light guide mirror 320, and a transmission screen 330 are arranged in a housing 340.
The rear projector 300 uses the light diffusing substrate 7 capable of suitably diffusing light in the transmissive screen 330. Therefore, the rear projector 300 can favorably diffuse light and has excellent display quality. It becomes a rear type projector.

As described above, since the unevenness 72 is formed in the light diffusing substrate 7, light can be suitably diffused and an inexpensive light diffusing substrate 7 can be manufactured.
Thereby, the transmissive screen and the rear projector using the light diffusing substrate 7 can diffuse light appropriately, and have excellent display quality (cost performance).

<Second Embodiment>
FIG. 6 is a longitudinal sectional view schematically showing a second embodiment of the optical system of the transmission screen of the present invention.
Hereinafter, the second embodiment of the transmission screen of the present invention will be described with reference to this figure, but the description will focus on the differences from the above-described embodiment, and the description of the same matters will be omitted.

This embodiment is the same as the first embodiment except that the direction (direction) in which the light diffusion substrate is installed is different.
As shown in FIG. 6, in the transmissive screen 330 </ b> A, the unevenness 72 (surface 71) of the light diffusion substrate 7 faces the Fresnel lens substrate 210. Thereby, it is possible to improve luminance by preventing / suppressing a decrease in transmittance.

<Third Embodiment>
FIG. 7 is a longitudinal sectional view schematically showing a third embodiment of the optical system of the transmission screen of the present invention.
Hereinafter, the third embodiment of the transmission screen of the present invention will be described with reference to this figure, but the description will focus on differences from the above-described embodiment, and the description of the same matters will be omitted.

This embodiment is the same as the first embodiment except that the shape of the light diffusion substrate is different.
As shown in FIG. 7, unevenness 72 is provided on the surfaces 71 and 73 of the light diffusion substrate 7A of the transmission screen 330B.
In such a transmission screen 330B, the unevenness 72 of the surface 71 of the light diffusion substrate 7A faces the microlens substrate 1, and the unevenness 72 of the surface 73 of the light diffusion substrate 7A faces the Fresnel lens substrate 210. . Thereby, the luminance can be improved by further preventing and suppressing the decrease in transmittance.
In addition, as for the unevenness 72 of the surface 71 and the unevenness 72 of the surface 73, at least one unevenness 72 should just satisfy the numerical range of the average pitch P.

<Fourth embodiment>
FIG. 8 is a longitudinal sectional view schematically showing a fourth embodiment of the optical system of the transmission screen of the present invention, and FIG. 9 is an exploded perspective view of the transmission screen shown in FIG.
Hereinafter, the fourth embodiment of the transmission screen of the present invention will be described with reference to these drawings. However, the difference from the above-described embodiment will be mainly described, and the description of the same matters will be omitted.

This embodiment is the same as the first embodiment except that the position where the light diffusion substrate is installed is different.
As shown in FIGS. 8 and 9, the light diffusing substrate 7 of the transmissive screen 330 </ b> C is disposed on the light emission surface side of the microlens substrate 1, that is, on the surface side where the microlenses 8 are not formed.

Further, in the transmissive screen 330 </ b> C, the light diffusion substrate 7 is disposed so that the surface 73 faces the microlens substrate 1. In other words, in the transmissive screen 330 </ b> C, the light diffusing substrate 7 is disposed so that the surface 71 becomes the light emitting surface of the light diffusing substrate 7.
With such an arrangement of the light diffusion substrate 7, external light (for example, sunlight or electric illumination light) incident on the transmission screen 330C can be suppressed (shielded), and thus light can be suitably diffused. That is, the contrast can be improved.

<Fifth Embodiment>
FIG. 10 is a longitudinal sectional view schematically showing a fifth embodiment of the optical system of the transmission screen of the present invention.
Hereinafter, a transmission screen according to a fifth embodiment of the present invention will be described with reference to this figure. However, the description will focus on differences from the above-described embodiment, and the description of the same matters will be omitted.

This embodiment is the same as the fourth embodiment except that the direction (direction) in which the light diffusion substrate is installed is different.
As shown in FIG. 10, in the transmissive screen 330 </ b> D, the unevenness 72 of the light diffusion substrate 7 faces the microlens substrate 1. Thereby, it is possible to improve luminance by preventing / suppressing a decrease in transmittance.

<Sixth Embodiment>
FIG. 11 is a longitudinal sectional view schematically showing a sixth embodiment of the optical system of the transmission screen of the present invention.
Hereinafter, the sixth embodiment of the transmission screen of the present invention will be described with reference to this drawing. However, the difference from the above-described embodiment will be mainly described, and the description of the same matters will be omitted.

The present embodiment is the same as the fourth embodiment except that the shape of the light diffusion substrate is different.
As shown in FIG. 11, irregularities 72 are provided on the surfaces 71 and 73 of the light diffusing substrate 7B in the transmissive screen 330E.
In such a transmissive screen 330E, the unevenness 72 of the surface 73 of the light diffusion substrate 7A is opposed to the microlens substrate 1. Thereby, the luminance can be improved by further preventing and suppressing the decrease in transmittance.

The light diffusing substrate, the method for manufacturing the light diffusing substrate, the transmissive screen, and the rear projector of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.
Further, the transmission screen 330 is not limited to having a microlens substrate, and may have a lenticular lens substrate instead of the microlens substrate, for example.

Further, in the transmissive screen 330, the microlens is not limited to being provided on the Fresnel lens substrate side, and may be provided on the opposite side to the Fresnel lens substrate side.
Further, in the transmissive screen 330, the light diffusion substrate is not limited to be disposed between the Fresnel lens substrate and the microlens substrate, or the light diffusion substrate is disposed on the emission surface side of the microlens substrate. For example, a light diffusion substrate may be disposed between the Fresnel lens substrate and the microlens substrate and on the emission surface side of the microlens substrate.

The unevenness of the mold is not limited to being formed by the wet blast method, and may be formed by, for example, a drive blast method, a shot blast method, photolithography, machining (for example, mechanical cutting), or the like.
Further, a particulate light diffusing material made of, for example, silica or glass may be dispersed inside the light diffusing substrate.

Moreover, the unevenness | corrugation similar to the unevenness | corrugation formed in the light-diffusion board | substrate may be provided in at least one of the surface in which the microlens of a microlens substrate and a microlens are not formed. For example, when unevenness similar to the unevenness of the light diffusion substrate is provided on both surfaces of the microlens substrate, the contrast in the transmission screen can be usually improved by 2 to 4%.
In the above description, the light diffusing substrate of the present invention is used as an example of a transmissive screen and a projection display device including the transmissive screen. However, the present invention is not limited to this. The light diffusing substrate of the present invention is not limited to various electro-optical devices such as CCDs and optical communication elements, liquid crystal display devices (liquid crystal panels), organic or inorganic EL (Electro luminescence) display devices, and others. Needless to say, it can be used in the above-mentioned apparatus.
Further, the display device is not limited to a rear projection type display device (rear projector), and for example, the light diffusion substrate of the present invention can be used for a front projection type display device.

Next, specific examples of the present invention will be described.
1. Production of light diffusion substrate 1 to 8 light diffusion substrates were produced.
(No. 1)
First, the metal mold | die for manufacturing a light-diffusion board | substrate was manufactured as shown below.

A plate member having a length of 1150 mm, a width of 650 mm, and a thickness of 2 mm was prepared as an original plate to be a mold. Further, the surface of the original plate is formed (configured) by nickel electroforming using a nickel sulfamate solution.
Next, as shown in FIG. 3, the entire surface of the mold original plate was roughened by a wet blast method.

The conditions in the wet blast method are as shown below.
・ Blasting liquid (treatment liquid): Aqueous dispersion of alumina particles (average particle size: 5 μm) ・ Pressure when colliding with blasting liquid: 0.2 MPa
Next, a light diffusion substrate was manufactured using the obtained mold.
First, a plate member having a length of 1100 mm, a width of 620 mm, and a thickness of 2.0 mm was prepared as an original plate to be a light diffusion substrate.
The constituent material of the original plate is polymethyl methacrylate (PMMA).

Next, as shown in FIG. 4, the original plate was pressed against a mold to produce a light diffusion substrate.
Hot press transfer was performed in a temperature range approximately 10 to 20 degrees higher than the glass transition temperature of polymethyl methacrylate (PMMA), which is the original plate material.
As described above, no. 1 light diffusion substrate was produced.
The surface roughness Rz of the obtained light diffusing substrate was as shown in Table 1.

(No. 2-6)
Each of the above-mentioned Nos. Was used except that an aqueous dispersion of particles having different average particle diameters was used when the mold was produced. In the same manner as in No. 1, a light diffusion substrate was produced.
In addition, the surface roughness Rz of each obtained light-diffusion board | substrate was as showing in Table 1, respectively.
(No. 7)
A light diffusing substrate (having both surfaces roughened) as shown in FIG. 3 was produced in the same manner as in No. 3.
The surface roughness Rz of the obtained light diffusing substrate was as shown in Table 1.
(No. 8)
When the mold was produced, the above-mentioned No. 1 was used except that an aqueous dispersion of particles having different average particle diameters (average particle diameter: 50 μm) was used. In the same manner as in No. 1, a light diffusion substrate was produced.
The surface roughness Rz of the obtained light diffusing substrate was as shown in Table 1.

2. Production of lens substrate (Example 1)
No. 1 was used to produce the transmission screen shown in FIG.
The specifications of the Fresnel lens substrate and the microlens substrate are as follows.

-Fresnel lens substrate Composition material: Glass Average thickness: 2 mm
・ Microlens substrate Component material: Glass Average thickness: 2mm

(Example 2)
No. A transmissive screen shown in FIG. 1 was manufactured in the same manner as in Example 1 except that the light diffusing substrate 2 was used.
(Example 3)
No. A transmissive screen shown in FIG. 1 was manufactured in the same manner as in Example 1 except that the light diffusing substrate 3 was used.

Example 4
No. A transmissive screen shown in FIG. 1 was produced in the same manner as in Example 1 except that the light diffusing substrate 4 was used.
(Example 5)
No. A transmissive screen shown in FIG. 1 was produced in the same manner as in Example 1 except that the light diffusing substrate 5 was used.

(Example 6)
No. A transmissive screen shown in FIG. 1 was produced in the same manner as in Example 1 except that the light diffusing substrate 6 was used.
(Example 7)
No. A transmissive screen shown in FIG. 7 was manufactured in the same manner as in Example 1 except that the light diffusing substrate 7 was used.

(Example 8)
No. A transmissive screen shown in FIG. 8 was manufactured except that the light diffusing substrate 3 was used.
The specifications of the Fresnel lens substrate and the microlens substrate are the same as those in the first embodiment.
Example 9
No. A transmissive screen shown in FIG. 11 was produced in the same manner as in Example 8 except that the light diffusing substrate 7 was used.

(Comparative Example 1)
No. A transmissive screen shown in FIG. 1 was manufactured in the same manner as in Example 1 except that the light diffusing substrate 8 was used.
(Comparative Example 2)
No. A transmissive screen shown in FIG. 8 was produced in the same manner as in Example 8 except that the light diffusing substrate 8 was used.

(Comparative Example 3)
A transmissive screen shown in FIG. 1 was produced in the same manner as in Example 1 except that the original light diffusion substrate used in the example was used as the light diffusion substrate.
(Comparative Example 4)
A transmissive screen shown in FIG. 8 was produced in the same manner as in Example 8 except that the original light diffusion substrate used in the example was used as the light diffusion substrate.

3. Evaluation Regarding the lens substrates manufactured in each Example and each Comparative Example, diffuse transmittance and haze value (HAZE value: (Pd / Pa) × 100, where diffuse transmittance is Pd and total transmittance is Pa) The value represented by
Moreover, the increase rate with respect to the front luminance of the transmission screen manufactured in Comparative Example 3 was measured for each of the transmission screens manufactured in each Example and Comparative Examples 1, 2, and 4.

The surface roughness Rz was measured using an electrical roughness measuring device.
The diffuse transmittance was measured with a spectrophotometer.
The total transmittance was measured with a spectrophotometer.
Further, the front luminance was measured by irradiating light from the flat surface side of the light diffusion substrate (original plate) and measuring the value at that time using an illuminometer.
These results are shown in Table 1, respectively.

As shown in Table 1, in all the lens substrates manufactured in each example, the rate of increase in front luminance was clearly high. In other words, any of the transmissive screens manufactured in each example could diffuse light appropriately.
Further, by setting the surface roughness Rz, the increase rate of the front luminance tends to increase, and the transmission screen having the light diffusion substrate in which the surface roughness Rz is set in the range of 0.05 to 0.1 Then, the rate of increase in front luminance was particularly high.
On the other hand, in each of the transmission screens manufactured in the comparative examples, the increase rate of the front luminance was extremely inferior. In other words, it is difficult for any of the transmissive screens manufactured in the comparative examples to diffuse light appropriately.

It is a longitudinal cross-sectional view which shows typically 1st Embodiment of the optical system of the transmission type screen of this invention. It is a disassembled perspective view of the transmission type screen shown in FIG. It is a longitudinal cross-sectional view which shows typically the process of manufacturing a type | mold. It is a longitudinal cross-sectional view which shows typically the process of manufacturing a light-diffusion board | substrate using the type | mold shown in FIG. It is a figure which shows typically the rear type | mold projector of this invention. It is a longitudinal cross-sectional view which shows typically 2nd Embodiment of the optical system of the transmission type screen of this invention. It is a longitudinal cross-sectional view which shows typically 3rd Embodiment of the optical system of the transmission type screen of this invention. It is a longitudinal cross-sectional view which shows typically 4th Embodiment of the optical system of the transmission type screen of this invention. FIG. 9 is an exploded perspective view of the transmission screen shown in FIG. 8. It is a longitudinal cross-sectional view which shows typically 5th Embodiment of the optical system of the transmission type screen of this invention. It is a longitudinal cross-sectional view which shows typically 6th Embodiment of the optical system of the transmissive screen of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Microlens board | substrate 7,7A, 7B ...... Light-diffusion board | substrate 70 ... Original board 71,73 ... Surface 72 ... Concavity and convexity 8 ... Microlens 210 ... Fresnel lens board 211 ... Fresnel lens 300 ... Rear type Projector 310... Projection optical unit 320... Light guide mirror 330, 330 A, 330 B, 330 C, 330 D, 330 E. Unevenness 500 …… Particle

Claims (20)

Light diffusion provided on a transmissive screen comprising a Fresnel lens substrate having a Fresnel lens formed on the light exit surface side and a lens substrate having a plurality of lenses formed on the exit surface side of the Fresnel lens substrate. A substrate,
A light diffusing substrate, wherein at least one surface thereof is provided with irregularities having a surface roughness Rz (ten-point average roughness specified in JIS B 0601) of 0.3 μm or less.   2. The light diffusion substrate according to claim 1, wherein an average pitch of the convex portions in the unevenness of the light diffusion substrate is 1 μm or less.   3. The light diffusion substrate according to claim 1, wherein an average pitch of the convex portions in the unevenness of the light diffusion substrate is 0.1 to 5.0% of an average diameter of the lenses of the lens substrate.   The light diffusion substrate according to any one of claims 1 to 3, wherein an average thickness of the light diffusion substrate is 1.0 to 5.0 mm. A method for producing the light diffusing substrate according to any one of claims 1 to 4,
By pressing a mold having a surface with irregularities on one surface of the original plate to be the light diffusion substrate, the irregular shape of the mold is transferred to one surface of the original plate to obtain the light diffusion substrate. A method of manufacturing a light diffusing substrate.   6. The method of manufacturing a light diffusing substrate according to claim 5, wherein the unevenness of the mold is formed by a blast method.   The method for manufacturing a light diffusing substrate according to claim 6, wherein the blasting method is a wet blasting method.   The method for producing a light diffusing substrate according to claim 6 or 7, wherein an average particle diameter of the colliding particles is 10 µm or less.   5. The Fresnel lens substrate in which a Fresnel lens is formed on the light exit surface side surface, the lens substrate that is disposed on the exit surface side of the Fresnel lens substrate and has a plurality of lenses, and any one of claims 1 to 4. A transmissive screen comprising the light diffusion substrate described above.   The transmissive screen according to claim 9, wherein the lens substrate is a microlens substrate.   The transmissive screen according to claim 9 or 10, wherein the light diffusion substrate is disposed between the Fresnel lens substrate and the lens substrate.   The transmissive screen according to claim 11, wherein the unevenness of the light diffusing substrate is provided on one surface of the light diffusing substrate, and the surface faces the lens substrate.   The transmissive screen according to claim 11, wherein the unevenness of the light diffusion substrate is provided on one surface of the light diffusion substrate, and the surface faces the Fresnel lens substrate.   The transmissive screen according to claim 11, wherein the unevenness of the light diffusing substrate is provided on both surfaces of the light diffusing substrate.   The transmissive screen according to claim 9 or 10, wherein the light diffusion substrate is disposed on an exit surface side of the lens substrate.   The transmissive screen according to claim 15, wherein the unevenness of the light diffusion substrate is provided on one surface of the light diffusion substrate, and the other surface faces the lens substrate.   The transmissive screen according to claim 15, wherein the unevenness of the light diffusion substrate is provided on one surface of the light diffusion substrate, and the surface faces the lens substrate.   The transmissive screen according to claim 15, wherein the unevenness of the light diffusing substrate is provided on both surfaces of the light diffusing substrate.   The transmissive screen according to claim 9, wherein the lens of the lens substrate is provided on the Fresnel lens substrate side. A rear projector comprising the transmissive screen according to any one of claims 9 to 19.

Images