JP2007156200A - Lens substrate, method for manufacturing lens substrate, transmissive screen, and rear projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens substrate capable of displaying images superior in contrast, to provide a method for manufacturing efficiently manufacturing the lens substrate, and to provide a transmissive screen and a rear projector equipped with the lens substrate. <P>SOLUTION: A microlens substrate 1 has a great number of microlenses (lens portions) 21 and is characterized in that: the substrate has a first region (colored part) 22 disposed near the surface of the microlenses 21 and colored in a predetermined density and a second region (non-colored part) 23 having a lower color density than the first region 22 and disposed in contact with tie first region 22; the boundary between the first region 22 and the second region 23 has recesses and projections; and the average pitch P<SB>B</SB>[μm] of the recesses and projections in the boundary between the first region 22 and second region 23, and the average pitch P<SB>L</SB>[μm] of the microlenses 21 satisfy a relation of P<SB>B</SB>>P<SB>L</SB>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

In recent years, the demand for rear projectors (rear projection projection televisions) is increasing as a display suitable for home theater monitors, large screen televisions, and the like.
In such a rear projector, in order to increase the contrast of an image, it is required to suppress external light reflection while suppressing a decrease in intensity of image light.
In order to achieve such an object, a lenticular lens substrate has been proposed that includes a colored layer having a substantially uniform thickness on the light incident surface of the lenticular lens (see, for example, Patent Document 1).

  However, with such a lenticular lens substrate, it has been difficult to sufficiently prevent reflection of external light. In addition, it is conceivable to increase the content of the colorant in the colored layer for the purpose of preventing reflection of external light. In such a case, the light transmittance itself for image formation itself is lowered and sufficiently bright. It was difficult to display images and images with sufficiently high contrast.

Japanese Patent Laid-Open No. 11-125704 (paragraph numbers 0050 to 0053, FIGS. 1 and 3)

  An object of the present invention is to provide a lens substrate capable of displaying an image with excellent contrast, to provide a manufacturing method capable of efficiently manufacturing the lens substrate, and to include the lens substrate. Another object is to provide a transmissive screen and a rear projector.

Such an object is achieved by the present invention described below.
The lens substrate of the present invention is a lens substrate having a lens portion as a number of convex lenses,
A first region colored at a predetermined density provided near the surface of the lens unit;
A color density lower than that of the first region, and a second region provided so as to be in contact with the first region,
The boundary between the first region and the second region is uneven,
When the average pitch of the irregularities at the boundary between the first region and the second region is P _B [μm] and the average pitch of the lens portions is P _L [μm], the relationship of P _B > P _L is established. It is characterized by satisfaction.
Thereby, the manufacturing method which can manufacture efficiently the lens substrate which can display the image excellent in contrast can be provided.

In the lens substrate of the present invention, it is preferable that the second region is not substantially colored.
Thereby, the contrast of the projected (displayed) image can be made particularly excellent.
In the lens substrate of the present invention, it is preferable that the lens portion is a microlens.
Thereby, the viewing angle characteristic can be made particularly excellent.

In the lens substrate of the present invention, the P _B is preferably 30 to 600 μm.
Thereby, the contrast of the displayed image can be made particularly excellent. Further, the durability of the lens substrate can be made particularly excellent.
In the lens substrate of the present invention, it is preferable that the average pitch P _L [μm] of the lens portions is 25 to 360 μm.
This makes it possible to obtain a sufficient resolution in the displayed image while making the viewing angle characteristics, the contrast of the projected image, and the luminance particularly excellent.

In the lens substrate of the present invention, it is preferable that the P _B and the P _L satisfy a relationship of 1.2 ≦ P _B / P _L ≦ 24.
Thereby, the contrast of the displayed image can be made particularly excellent. Further, the durability of the lens substrate can be made particularly excellent.
In the lens substrate of the present invention, it is preferable that the P _B and the P _L satisfy a relationship of 5.0 ≦ P _B −P _L ≦ 575.
Thereby, the contrast of the displayed image can be made particularly excellent. Further, the durability of the lens substrate can be made particularly excellent.

In the lens substrate of the present invention, it is preferable that the average thickness of the first region in the vicinity of the top portion of the lens portion is 10 to 400 μm.
Thereby, the contrast of the displayed image can be made particularly excellent.
In the lens substrate of the present invention, it is preferable that the height difference of the unevenness at the boundary between the first region and the second region is 15 to 360 μm.
Thereby, the contrast of the displayed image can be made particularly excellent. Further, the durability of the lens substrate can be made particularly excellent.

In the lens substrate of the present invention, the coloring density of the first region is preferably 20 to 95% in terms of a Y value (D65 / 2 ° field of view).
Thereby, the contrast of the displayed image can be made particularly excellent.
In the lens substrate of the present invention, it is preferable that the arrangement of the lens portions is a staggered arrangement, and the arrangement of irregularities at the boundary between the first region and the second region is a honeycomb arrangement.
Thereby, the contrast of the displayed image can be made particularly excellent. Further, the durability of the lens substrate can be made particularly excellent.

The manufacturing method of the lens substrate of the present invention includes:
Forming a second region on the substrate using a mold;
A step of forming a first region by applying a composition containing a colorant and a resin material on the second region and forming the composition into a predetermined shape.
Thereby, it is possible to provide a lens substrate manufacturing method capable of efficiently manufacturing a lens substrate capable of displaying an image with excellent contrast.

In the lens substrate manufacturing method of the present invention, it is preferable that the second region is formed so that the surface shape thereof is a microlens shape.
Thereby, the uneven | corrugated area | region can be formed with the completely same manufacturing method as a lens, and manufacturing cost can be held down.
The transmission screen of the present invention is characterized by including the lens substrate of the present invention.
Thereby, it is possible to provide a transmissive screen capable of displaying an image with excellent contrast.

The transmissive screen of the present invention, a Fresnel lens portion in which a Fresnel lens is formed on the light emission side,
And a lens substrate of the present invention disposed on the light emission side of the Fresnel lens portion.
Thereby, it is possible to provide a transmissive screen capable of displaying an image with excellent contrast.
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 display an image with excellent contrast.

Hereinafter, a lens substrate, a method for manufacturing a lens substrate, a transmissive screen, and a rear projector of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
First, the configuration of the lens substrate and the transmission screen of the present invention will be described.
1 is a schematic longitudinal sectional view showing a preferred embodiment of a lens substrate (microlens substrate) of the present invention, FIG. 2 is a schematic plan view of the lens substrate shown in FIG. 1, and FIG. 2 is a schematic longitudinal sectional view showing a preferred embodiment of a transmission screen of the present invention including the lens substrate shown in FIG. In the following description, the left side in FIGS. 1 and 3 is referred to as “(light) incident side”, and the right side is referred to as “(light) emission side”. In the present invention, unless otherwise specified, the “(light) incident side” and the “(light) output side” are the “incident side” of light for obtaining image light (video light), respectively. ”And“ outgoing side ”, not“ incident side ”or“ outgoing side ”of external light or the like.

  A microlens substrate (lens substrate) 1 is a member constituting a transmissive screen 10 described later, and has a substrate body 2 having a plurality of microlenses (lens portions) 21 as shown in FIG. Yes. The substrate body 2 is provided so that the first region 22 provided near the surface of the microlens 21 has a lower coloring density than the first region 22 and is in contact with the first region 22. And a second region 23. The second region 23 only needs to have a lower coloring density than the first region 22, but in the present embodiment, it is preferable that the second region 23 is not substantially colored. As a result, the light transmittance from the light incident side can be made sufficiently high while preventing reflection of external light sufficiently effectively, and the contrast of the displayed image is particularly excellent. be able to. In the following description, it is assumed that the first region 22 is a colored portion colored at a predetermined concentration and the second region 23 is a non-colored portion that is not substantially colored unless otherwise specified. . Note that the microlens substrate 1 is composed of another configuration (not shown), for example, a diffusion portion that is provided on the light emission side of the substrate body and has a function of diffusing the light transmitted through the substrate body, or a light shielding material. It may have a black matrix (light-shielding portion) or the like.

The constituent material of the substrate body 2 is not particularly limited, but is mainly composed of a resin material (usually, the refractive index of light is larger than that of air).
Specific examples of the constituent material of the substrate body 2 (material whose light refractive index is larger than that of air) include polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer (EVA). , Cyclic polyolefin, modified polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide (example: nylon 6, nylon 46, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 6-12, nylon 6-6) 66), polyimide, polyamideimide, polycarbonate (PC), poly- (4-methylpentene-1), ionomer, acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene copolymer ( AS Fat), butadiene-styrene copolymer, polyoxymethylene, polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polycyclohexane terephthalate (PCT) Polyester, polyether, polyetherketone (PEK), polyetheretherketone (PEEK), polyetherimide, polyacetal (POM), polyphenylene oxide, modified polyphenylene oxide, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate , Aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyvinylidene fluoride, other fluororesins, styrene, polyolefin Various thermoplastic elastomers such as vinyl resin, polyvinyl chloride, polyurethane, polyester, polyamide, polybutadiene, trans polyisoprene, fluoro rubber, chlorinated polyethylene, epoxy resin, phenol resin, urea resin, Melamine resins, unsaturated polyesters, silicone resins, urethane resins, etc., or copolymers, blends, polymer alloys, etc. mainly composed of these, may be used, and one or more of these may be combined ( For example, from the viewpoint of transparency, polystyrene, polycarbonate, polyethylene terephthalate, and acrylic resin are preferable, and acrylic resin is particularly preferable among them. Acrylic resins have excellent transparency and are excellent in heat resistance, light resistance, workability, dimensional accuracy when molded, mechanical strength, etc., and as a constituent material of lens substrates (substrate body) Is preferred. In addition, acrylic resins are generally relatively inexpensive and advantageous from the standpoint of manufacturing costs.

As an acrylic resin, for example, an acrylic resin having acrylic acid or a derivative thereof (for example, acrylic ester) as a constituent monomer, a methacrylic resin having a constituent monomer of methacrylic acid or a derivative thereof (for example, methacrylic ester), for example. Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid ester copolymer, styrene-α-chloroacrylic acid methyl copolymer, styrene-acrylonitrile-acrylic acid A copolymer containing (meth) acrylic acid such as an ester copolymer or a derivative thereof as a constituent monomer can be used, and one or more selected from these can be used in combination.
Moreover, in order to diffuse the incident light from the light source, the substrate main body 2 may contain, for example, polystyrene beads, glass beads, organic cross-linked polymers, etc. as a diffusing material, as necessary. Note that the diffusing material may be included in the entire resin (the entire substrate body 2), or may be included in only a part thereof.

  In the present embodiment, the microlens 21 has a vertical width (width in the vertical direction (length indicated by X in the figure)) in the plan view of the microlens substrate 1 and a horizontal width (indicated by Y in the figure). It has a flat shape (substantially elliptical, substantially bowl-shaped) smaller than the length)). When the microlens 21 has such a shape, it is possible to make the viewing angle characteristics particularly excellent while effectively preventing the occurrence of inconvenience such as moire. In particular, both the horizontal and vertical viewing angle characteristics can be improved. Moreover, the brightness of the projected image can be made higher.

  When the length in the minor axis direction (vertical direction) of the microlens 21 in plan view is X [μm] and the length in the major axis direction (lateral direction) is Y [μm], 0.10 ≦ X / It is preferable to satisfy the relationship of Y ≦ 0.99, more preferable to satisfy the relationship of 0.50 ≦ X / Y ≦ 0.95, and to satisfy the relationship of 0.75 ≦ X / Y ≦ 0.90 More preferably. By satisfying the relationship as described above, the effects as described above become more remarkable.

  The length of the microlens 21 in the minor axis direction (vertical width of the microlens 21) when viewed in plan is preferably 10 to 180 μm. When the length of the microlens 21 in the short axis direction (vertical width of the microlens 21) is a value within the above range, the viewing angle characteristics of the microlens substrate 1, the contrast of the projected image, and the brightness are particularly excellent. It can be. Further, when the length of the microlens 21 in the short axis direction (the width of the microlens 21) is a value within the above range, it is possible to effectively prevent the occurrence of inconvenience such as moire and the microlens substrate 1. Productivity can be further increased.

  Moreover, it is preferable that the length of the major axis direction of the microlens 21 when viewed in plan is 15 to 200 μm. When the length in the major axis direction of the microlens 21 is a value within the above range, the viewing angle characteristics of the microlens substrate 1, the contrast of the projected image, and the luminance can be made particularly excellent. Further, when the length of the microlens 21 in the major axis direction is a value within the above range, it is possible to effectively prevent the occurrence of inconvenience such as moire and further increase the productivity of the microlens substrate 1. Can do.

  The pitch of the microlenses 21 in the minor axis direction is preferably 30 to 600 μm. When the pitch in the minor axis direction of the microlens 21 is a value within the above range, the viewing angle characteristics of the microlens substrate 1, the contrast of the projected image, and the luminance can be made particularly excellent. In addition, when the pitch of the microlenses 21 in the minor axis direction is a value within the above range, it is possible to effectively prevent inconveniences such as moire and to further increase the productivity of the microlens substrate 1. it can.

  Moreover, it is preferable that the pitch in the major axis direction of the microlens 21 when viewed in plan is 30 to 600 μm. When the pitch in the major axis direction of the microlens 21 is a value within the above range, the viewing angle characteristics of the microlens substrate 1, the contrast of the projected image, and the luminance can be made particularly excellent. Moreover, when the pitch in the major axis direction of the microlens 21 is a value within the above range, it is possible to effectively prevent the occurrence of inconvenience such as moire and further increase the productivity of the microlens substrate 1. it can.

  Further, the radius of curvature of the microlens 21 is preferably 15 to 180 μm. When the radius of curvature of the microlens 21 is a value within the above range, the viewing angle characteristics can be made particularly excellent. In particular, both the horizontal and vertical viewing angle characteristics can be improved. The microlens 21 may have a different radius of curvature in the minor axis direction and a radius of curvature in the major axis direction. In such a case, the radius of curvature in the major axis direction is a value within the above range. Is preferred.

Further, the height of the microlens 21 (the height of the microlens 21 as a convex portion) is preferably 10 to 180 μm. When the height of the microlens 21 is within the above range, the viewing angle characteristics can be made particularly excellent.
The plurality of microlenses 21 are arranged in a staggered pattern (in a staggered pattern). By arranging the microlenses 21 in this way, it is possible to effectively prevent inconveniences such as moire. On the other hand, for example, if the microlenses are arranged in a square lattice shape or the like, it may be difficult to sufficiently prevent the occurrence of inconvenience such as moire depending on the size of the microlenses 21 and the like. . Further, when the microlenses are randomly arranged, depending on the size of the microlens 21 or the like, it becomes difficult to sufficiently increase the occupation ratio of the microlenses in the effective region where the microlenses are formed. It is difficult to sufficiently increase the transmittance (light utilization efficiency), and the obtained image may be dark.

  As described above, in the present embodiment, the microlenses 21 are arranged in a staggered pattern when the microlens substrate 1 is viewed in plan view, but the first row configured by the plurality of microlenses 21. 28 and the adjacent second row 29 are preferably offset by a half pitch in the vertical direction. As a result, it is possible to more effectively prevent the occurrence of moire due to light interference and to make the viewing angle characteristics particularly excellent.

The arrangement method of the microlenses 21 is not limited to the one described above. For example, even if the arrangement is a square lattice, the arrangement is optically random (from the main surface side of the microlens substrate 1 in plan view). In this case, the microlenses 21 may be arranged in a random positional relationship with each other.
Further, when the microlens substrate 1 is viewed in plan from the light incident surface side (direction shown in FIG. 2), the occupation ratio of the microlens 21 is 90 to 100 in the effective region where the microlens 21 is formed. % Is preferred. When the occupation ratio of the microlens 21 is a value within the above range, the light use efficiency can be further improved, and the brightness and contrast of the projected image can be made particularly excellent. The occupation ratio of the microlens 21 is a line segment connecting the center 211 of the microlens 21 when viewed in plan and the central portion of the portion adjacent to the microlens 21 where the microlens 21 is not formed. It can be determined as a ratio (L ₃ / L ₄ × 100 [%]) between the length L ₃ [μm] of the portion where the microlens 21 is formed and the length L ₄ [μm] of the line segment. (See FIG. 2).

  As described above, by strictly defining the shape and arrangement method of the microlenses, the viewing angle characteristics and the like can be made particularly excellent while effectively preventing the occurrence of moire due to light interference. . In particular, by strictly defining the shape and arrangement method of the microlens as described above, the effect of having the microlens having the shape and arrangement method as described above, and the first area described in detail later In addition, the effects of having the second region act synergistically, and particularly excellent effects (for example, particularly excellent viewing angle characteristics, light utilization efficiency, etc.) can be obtained.

Each microlens 21 is formed as a convex lens protruding to the incident side, and is designed so that the focal point f is located in the vicinity of the surface on the emission side of the substrate body 2. That is, parallel light La (parallel light La from a Fresnel lens unit 5 described later) incident on the microlens substrate 1 from a substantially vertical direction is condensed by each microlens 21 of the microlens substrate 1 and The focal point f is set near the surface on the exit side of the main body 2.
Further, at this time, by forming the black matrix so as to open in the vicinity of the focal point f, the light utilization efficiency can be further improved.

  A colored portion (first region) 22 colored with a predetermined density is provided near the surface of the microlens 21 of the substrate body 2. The colored portion (first region) 22 can sufficiently transmit light incident from the incident side, and external light (for example, external light incident unintentionally from the light emitting side) is emitted. It has a function of preventing reflection to the side, and this can effectively prevent a decrease in contrast of the displayed image.

Further, a non-colored portion (second region) 23 is provided on the light emission side of the colored portion (first region) 22 so as to contact the colored portion (first region) 22. . The boundary between the colored portion 22 and the non-colored portion 23 is uneven, and the average pitch of the unevenness (hereinafter also referred to as “boundary unevenness”) between the colored portion 22 and the non-colored portion 23 is P. _{When B} [μm] and the average pitch of the microlenses (lens portion) 21 are P _L [μm], the relationship of P _B > P _L is satisfied.
By satisfying such a relationship, it is possible to effectively prevent a reduction in image contrast caused by reflection of external light incident from the light emission side (the side opposite to the side where the microlens 21 is provided). The transmittance of light (image forming light) from the light incident side can be made sufficiently high, and variations in viewing angle characteristics in each direction can be effectively prevented.

More specifically, external light incident from the light emission side passes through the non-colored portion 23 and reaches the colored portion 22. Most of the outside light is absorbed in the vicinity of the surface of the reached colored portion 22. On the other hand, a part of the incident external light is reflected near the surface of the colored portion 22 (near the interface between the colored portion 22 and the non-colored portion 23), but in the microlens substrate 1, the colored portion 22 and the non-colored portion are reflected. Since the unevenness with a relatively large pitch is formed on the boundary with the surface 23, the surface of the colored portion 22 (near the interface between the colored portion 22 and the non-colored portion 23) is utilized by using the height difference of the large unevenness and the curved surface of the unevenness. There is a high possibility that the external light reflected by the light reaches another surface inside the unevenness of the colored portion 22 again (see FIG. 1). Then, by repeating such reflection, the intensity of the reflected light is rapidly attenuated. Accordingly, the influence of the external light on the image contrast is extremely small. Further, since the microlenses 21 are colored and the pitch and height difference of the boundary irregularities are larger than the pitch of the microlenses 21, the color density of the concave portions and the convex portions are observed when the boundary irregularities are observed from the emission side. There appears to be a difference in the color density. As a result, reflection of external light can be prevented and blackness can be enhanced, and as a result, an image with high visual contrast can be obtained. Moreover, the contact area of the coloring part 22 and the non-coloring part 23 becomes a comparatively big thing by being the above structures. For this reason, the adhesion between the colored portion 22 and the non-colored portion 23 is excellent, and the durability and reliability of the microlens substrate 1 are particularly excellent.
On the other hand, when the above relationship is not satisfied, the excellent effect as described above cannot be obtained.

  That is, as shown in FIG. 9, when the pitch of the unevenness at the boundary between the colored portion and the non-colored portion is the same as the pitch of the lens portion, a decrease in contrast due to reflection of external light cannot be sufficiently prevented. . Further, in the lens substrate configured as shown in FIG. 9, it is difficult to set conditions at the time of manufacture, and as shown in FIG. 10, when the structure of the convex portion is slightly shifted, the colored portion in each direction The variation in the thickness tends to increase. When such a thickness variation occurs, the viewing angle characteristics in each direction are greatly different (for example, the luminance when viewed from the right side and the luminance when viewed from the left side are greatly different). . In addition, it is necessary to accurately align the position of the convex portion in the manufacture. For this purpose, as shown in FIG. 11, the height of the unevenness at the boundary is remarkably reduced to absorb the positional deviation. In this case, the above-mentioned problem becomes more prominent.

  In addition, as shown in FIG. 12, when the pitch of the unevenness at the boundary between the colored portion and the non-colored portion is smaller than the pitch of the lens portion, it is caused by the reflection of external light as in the configuration shown in FIG. The decrease in contrast becomes significant. That is, even if the external light is reflected once on the surface of the uneven portion at the boundary, it cannot be reflected to the extent that it is sufficiently attenuated because the pitch and height difference of the uneven portions are low. In addition, in the lens substrate configured as shown in FIG. 12, the thickness of the colored portion for each lens portion is increased. Therefore, when the entire lens shown in FIG. 13 is colored, that is, the colored portion and the non-colored portion. There is no difference from the case where the boundary of is flat.

In the case of the structure as shown in FIG. 13, the contrast decreases due to the reflection of external light, as compared with the structure shown in FIGS. 9 and 12. In addition, in the configuration as shown in FIG. 12, the contact area between the colored portion and the non-colored portion is smaller than that of the above-described microlens substrate of the present invention, so that the adhesion between the colored portion and the non-colored portion is inferior. It will be a thing.
As described above, when the average pitch of the boundary irregularities is P _B [μm] and the average pitch of the microlenses (lens part) 21 is P _L [μm], the relationship of P _B > P _L is satisfied. Preferably satisfies the relationship of 5 ≦ P _B −P _L ≦ 575, more preferably satisfies the relationship of 10 ≦ P _B −P _L ≦ 250, and the relationship of 15 ≦ P _B −P _L ≦ 150 Is more preferable. As a result, reflection of external light can be prevented more effectively, an image with higher contrast can be displayed, and problems such as variations in viewing angle characteristics and color unevenness in each direction can be further generated. It can be surely prevented. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

Further, 1.2 ≦ _P is preferable to satisfy ≦ 24 relationship B / _{P L,} more preferably satisfies ≦ 12 relationship _{1.3 ≦ P B / P L,} 1.5 ≦ P _It is more preferable to satisfy the relationship of _B / P _L ≦ 5. As a result, reflection of external light can be prevented more effectively, an image with higher contrast can be displayed, and problems such as variations in viewing angle characteristics and color unevenness in each direction can be further generated. It can be surely prevented. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

Specific value of the average pitch _{P B} of the boundary unevenness is not particularly limited, but is preferably 30～600Myuemu, more preferably from 40～450Myuemu, even more preferably 50 to 300 [mu] m. When P _B is a value within the above range, reflection of external light can be more effectively prevented, an image with higher contrast can be displayed, and variations in viewing angle characteristics in each direction Occurrence of problems such as color unevenness can be prevented more reliably. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

Moreover, although the height difference F _B of the boundary unevenness is not particularly limited, it is preferably 15 to 360 μm, more preferably 25 to 250 μm, and further preferably 30 to 200 μm. When the height difference F _B of the boundary unevenness is within this range, it is possible to prevent the reflection of external light more effectively, it is possible to display a higher image contrast, field of view in each direction Occurrence of problems such as variations in angular characteristics and color unevenness can be prevented more reliably. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

Moreover, the ratio (F _B / P _B ) of the height difference F _B of the boundary unevenness to the average pitch P _B of the boundary unevenness is not particularly limited, but is preferably 0.5 to 2. When F _B / P _B is a value within the above range, reflection of external light can be more effectively prevented, an image with higher contrast can be displayed, and viewing angle characteristics in each direction Occurrence of problems such as variations in color and color unevenness can be prevented more reliably. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

In addition, when the pitch of the microlens (lens part) 21 in each direction in the surface of the microlens substrate (lens substrate) 1 is different as in the present embodiment, the pitch of the microlens (lens part) 21 is the maximum. a microlens (lens unit) 21 pitch in the composed direction may be adopted as the P _L, but the micro-lenses (lens unit) in a direction pitch of the micro lenses (lens portion) 21 is minimized for 21 pitch also It is preferable to satisfy the above relationship, and it is more preferable to satisfy the above relationship in all directions within the surface of the microlens substrate 1. Thereby, the effects as described above become more remarkable.

Further, when the average width of each convex portion constituting the boundary unevenness is W _C [μm] and the average width of the microlens (lens portion) 21 is W _L [μm], the relationship of W _C > W _L is satisfied. It is more preferable that the relationship 5 ≦ W _C −W _L ≦ 575 is satisfied, and it is more preferable that the relationship 10 ≦ W _C −W _L ≦ 250 is satisfied. As a result, reflection of external light can be prevented more effectively, an image with higher contrast can be displayed, and problems such as variations in viewing angle characteristics and color unevenness in each direction can be further generated. It can be surely prevented. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

Further, it is preferable that the relationship of ≦ 24 of 1.2 ≦ W _C / W _L is satisfied, more preferably the relationship of ≦ 12 of 1.3 ≦ W _C / W _L is satisfied, and 1.5 ≦ W _It is more preferable to satisfy the relationship of _C / W _L ≦ 5. As a result, reflection of external light can be prevented more effectively, an image with higher contrast can be displayed, and problems such as variations in viewing angle characteristics and color unevenness in each direction can be further generated. It can be surely prevented. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

Specific value of the average width _{W C} of the convex portion constituting the boundary unevenness is not particularly limited, but is preferably 30～600Myuemu, more preferably from 40～450Myuemu, in the range of 50~300μm Is more preferable. When W _C is within this range, it is possible to prevent the reflection of external light more effectively, it is possible to display a higher image contrast, Ya variation in viewing angle characteristics in each direction Occurrence of problems such as color unevenness can be prevented more reliably. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

The ratio of the height difference _{F B} of the boundary unevenness to the average width _{W C} of the convex portion constituting the boundary unevenness _(F B / _{W C)} is not particularly limited, but is preferably from 0.5 to 2. When F _B / W _C is a value within the above range, reflection of external light can be more effectively prevented, an image with higher contrast can be displayed, and viewing angle characteristics in each direction Occurrence of problems such as variations in color and color unevenness can be prevented more reliably. Further, the adhesion between the colored portion 22 and the non-colored portion 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be made particularly excellent.

Note that when the width of the microlens (lens portion) 21 in each direction within the surface of the microlens substrate (lens substrate) 1 is different as in this embodiment, the width of the microlens (lens portion) 21 is the maximum. the width of the micro-lens (lens section) 21 in the composed direction may be adopted as W _L, but the micro-lenses (lens portion) in the direction in which the width of the micro-lenses (lens portion) 21 is minimized for 21 pitch also It is preferable to satisfy the above relationship, and it is more preferable to satisfy the above relationship in all directions within the surface of the microlens substrate 1. Thereby, the effects as described above become more remarkable.

The array pattern of the boundary irregularities is preferably a honeycomb shape, but is not particularly limited. For example, it may be a staggered pattern similar to the above-described array pattern of the microlenses 21 (same except that the pitch is different), or square. It may be a lattice. Further, the arrangement pattern of the boundary irregularities may be random.
The average thickness _{D 1} of the first region (colored part) 22 in the vicinity of the apex of the microlens 21 is not particularly limited, but is preferably 10 to 400 [mu] m, more preferably from 20 to 300 [mu] m,. 30 to More preferably, it is 200 μm. When the average thickness D1 of the _first region 22 is a value within the above range, the contrast of the displayed image can be made particularly excellent.

The coloring density of the first region (colored portion) 22 is not particularly limited, but is preferably 20 to 95% in terms of Y value (D65 / 2 ° field of view), more preferably 30 to 85%. More preferably, it is 35 to 75%. When the color density of the first region (colored portion) 22 is a value within the above range, the contrast of the displayed image can be made particularly excellent.
The color of the first region (colored portion) 22 is not particularly limited, but is based on blue, uses a colorant mixed with red, brown, or yellow, and has an achromatic and black appearance. It is preferable to selectively absorb or transmit light of a specific wavelength that controls the balance of the three primary colors. This effectively prevents reflection of external light, accurately represents the color tone of the image formed by the light transmitted through the microlens substrate, and has a wide color coordinate (the range of color tone expression is sufficiently wide). ), A deeper black can be expressed, and as a result, the contrast can be made particularly excellent.

The refractive index (absolute refractive index) of the constituent material of the first region (colored portion) 22 is I ₁ , and the refractive index (absolute refractive index) of the constituent material of the second region (non-colored portion) 23 is I ₂ . In this case, it is preferable to satisfy the relationship of −0.20 ≦ I ₁ −I ₂ ≦ 0.20, and it is preferable to satisfy the relationship of −0.10 ≦ I ₁ −I ₂ ≦ 0.10. Thus, the difference between the refractive index (absolute refractive index) of the constituent material of the first region (colored portion) 22 and the refractive index (absolute refractive index) of the constituent material of the second region (non-colored portion) 23. If the absolute value is sufficiently small, the optical characteristics of the microlens substrate 1 can be controlled easily and reliably.

  Moreover, it is preferable that the main component which comprises the 1st area | region 22 and the main component which comprises the 2nd area | region 23 are substantially the same. Thereby, the difference between the refractive index (absolute refractive index) of the constituent material of the first region (colored portion) 22 and the refractive index (absolute refractive index) of the constituent material of the second region (non-colored portion) 23 is reduced. The absolute value can be made sufficiently small, and the adhesion between the first region 22 and the second region 23 can be made particularly excellent, and the durability and reliability of the microlens substrate 1 can be improved. It can be made particularly excellent.

The constituent material of the base material 26 may be the same as or different from the constituent material of the first region 22 and the constituent material of the second region 23, but the refractive index of the constituent material may be different. The difference is preferably small.
Further, the refractive index I ₁ of the material of the first region (colored part) 22, the refractive index of the material of refractive index I ₂ and the substrate 26 of the material of the second region (non-colored portion) 23 I _{Also for 0} , it is preferable that the refractive index difference satisfies the relationship of −0.20 ≦ I ₁ −I ₀ ≦ 0.20 or −0.20 ≦ I ₂ −I ₀ ≦ 0.20.

Further, a black matrix may be provided on the light emitting surface of the microlens substrate 1. In this case, the black matrix is made of a light-shielding material and is formed in layers. By having such a black matrix, the black matrix can absorb external light (external light unfavorable for forming a projection image), and the image projected on the screen has an excellent contrast. Can be. In particular, by having the first region (colored portion) 22 as described above and a black matrix, the contrast of the image by the microlens substrate 1 can be made particularly excellent.
Such a black matrix desirably has an opening on the optical path of the light transmitted through each microlens 21. Thereby, the light condensed by each micro lens 21 can be efficiently passed through the opening of the black matrix. As a result, the light utilization efficiency of the microlens substrate 1 can be increased.

The size of the opening of the black matrix is not particularly limited, but the diameter is preferably 5 to 100 μm. Thereby, the image projected on a screen can be made more excellent in contrast.
Moreover, it is preferable that the thickness (average thickness) of a black matrix is 0.01-5 micrometers. When the thickness of the black matrix is a value within the above range, the function as a black matrix can be more effectively exhibited while more reliably preventing unintentional peeling, cracking, etc. of the black matrix. In the transmissive screen 10 including the microlens substrate 1, the contrast of the projected image can be made particularly excellent.

  Further, when the microlens substrate 1 is viewed in plan from the light incident surface side (direction shown in FIG. 2), in an effective region where the microlens 21 is formed, a black matrix (a region other than the opening portion of the black matrix). ) Is preferably 1 to 70%, and more preferably 1 to 50%. When the proportion of the area occupied by the black matrix is a value within the above range, the image projected on the screen can be made excellent in contrast while the light use efficiency is sufficiently high.

Next, the transmission screen 10 including the microlens substrate 1 as described above will be described.
As shown in FIG. 3, the transmission screen 10 includes a Fresnel lens portion 5 and the microlens substrate 1 described above. The Fresnel lens unit 5 is installed on the light (image light) incident side, and the light transmitted through the Fresnel lens unit 5 is incident on the microlens substrate 1.
The Fresnel lens unit 5 has a prism-shaped Fresnel lens 51 formed in a substantially concentric shape on the exit side surface. The Fresnel lens unit 5 refracts image light from a projection lens (not shown) to produce parallel light La parallel to the vertical direction of the main surface of the microlens substrate 1.

In the transmissive screen 10 configured as described above, the image light from the projection lens is refracted by the Fresnel lens unit 5 and becomes parallel light La. The parallel light La is incident on the surface side of the microlens substrate 1 where the first region 22 is formed, is condensed by each microlens 21, and is emitted from the opposite surface side. When the microlens substrate 1 has a black matrix, the light collected by each microlens 21 passes through the opening of the black matrix (light shielding layer).
At this time, the light incident on the microlens substrate 1 is transmitted through the microlens substrate 1 with sufficient transmittance. The light emitted from the microlens substrate 1 is diffused and observed as a planar image by the observer.

Next, an example of a method for manufacturing the above-described microlens substrate 1 will be described.
FIG. 4 is a schematic longitudinal sectional view showing a member with a recess used for manufacturing a microlens substrate, and FIG. 5 is a schematic longitudinal sectional view showing a method for manufacturing the member with a recess shown in FIG. 6 and 7 are schematic longitudinal sectional views showing an example of a manufacturing method of the microlens substrate shown in FIG. In the following description, the lower side in FIGS. 6 and 7 is referred to as “(light) incident side”, and the upper side is referred to as “(light) emission side”.
Further, in the manufacture of the member with concave portions, a large number of concave portions (recesses for microlenses) are actually formed on the substrate, and in the manufacture of the microlens substrate (substrate body), actually a large number of convex portions (convex lenses). However, in order to make the explanation easier to understand, a part thereof is highlighted.

First, prior to the description of the manufacturing method of the microlens substrate, the configuration of the member with recesses (the member with recesses for forming microlenses) used for manufacturing the microlens substrate will be described.
The member with concave portions (member with concave portions for forming microlenses) 6 may be made of any material, but is preferably made of a material that is less likely to bend and is less likely to be damaged. Examples of the constituent material of the member 6 with recesses include soda glass, crystalline glass, quartz glass, lead glass, potassium glass, borosilicate glass, and alkali-free glass. Especially, as a constituent material of the member 6 with a recessed part, soda glass, crystalline glass (for example, neo-serum etc.), and an alkali free glass are preferable. Soda glass, crystalline glass, and alkali-free glass are easy to process, are relatively inexpensive, and are advantageous from the viewpoint of manufacturing cost.

  The member with recesses (member with recesses for forming microlenses) 6 includes a plurality of recesses (recesses for forming microlenses) 61 arranged in a manner corresponding to the arrangement method of the microlenses 21 (transferred positional relationship). ing. These recesses 61 have a shape corresponding to the microlens 21 (substantially the same shape except for the transferred shape) and dimensions, except that the microlens 21 is a recess while the microlens 21 is a protrusion. have.

  More specifically, in the present embodiment, the recess (microlens formation recess) 61 has a vertical width (width in the vertical direction) smaller than the horizontal width (width in the horizontal direction) when the member 6 with recesses is viewed in plan. It has a flat shape (substantially oval or substantially bowl-shaped). The concave portion 61 having such a shape is preferably used for manufacturing the microlens substrate 1 capable of effectively preventing the occurrence of inconvenience such as moire and having particularly excellent viewing angle characteristics. Can do.

  Further, when the length in the minor axis direction (longitudinal direction) of the recess 61 in plan view is X [μm] and the length in the major axis direction (lateral direction) is Y [μm], 0.10 ≦ X /Y≦0.99 is preferably satisfied, 0.50 ≦ X / Y ≦ 0.95 is more preferable, and 0.75 ≦ X / Y ≦ 0.90 is satisfied. It is more preferable to satisfy. By satisfying the relationship as described above, the effects as described above become more remarkable.

  Moreover, it is preferable that the length (width | variety of the recessed part 61) of the minor axis direction of the recessed part 61 when planarly viewed is 10-180 micrometers. When the length of the concave portion 61 in the minor axis direction is a value within the above range, the viewing angle characteristics of the manufactured microlens substrate 1 and the contrast and brightness of the image projected by the microlens substrate 1 are particularly excellent. However, sufficient resolution can be obtained in the projected image. Further, when the length of the concave portion 61 in the short axis direction is a value within the above range, it is possible to effectively prevent the occurrence of inconvenience such as moire when the manufactured microlens substrate 1 is used. The productivity of the microlens substrate 1 (member 6 with a recess) can be further increased.

  Moreover, it is preferable that the length of the major axis direction of the recessed part 61 when it planarly views is 15-200 micrometers. When the length of the concave portion 61 in the major axis direction is a value within the above range, the viewing angle characteristics of the manufactured microlens substrate 1 and the contrast and brightness of the image projected by the microlens substrate 1 are particularly excellent. It can be. Further, when the length of the concave portion 61 in the major axis direction is a value within the above range, it is possible to effectively prevent the occurrence of inconvenience such as moire when the manufactured microlens substrate 1 is used. The productivity of the microlens substrate 1 (member 6 with a recess) can be further increased.

  The pitch in the minor axis direction of the recesses 61 is preferably 30 to 600 μm. When the pitch of the concave portions 61 in the minor axis direction is a value within the above range, the viewing angle characteristics of the manufactured microlens substrate 1 and the contrast and brightness of the image projected by the microlens substrate 1 are particularly excellent. can do. Further, when the pitch in the minor axis direction of the recess 61 is a value within the above range, it is possible to effectively prevent the occurrence of inconvenience such as moire when the manufactured microlens substrate 1 is used, Productivity of the microlens substrate 1 (member 6 with a recess) can be further increased.

  Moreover, it is preferable that the pitch in the major axis direction of the recessed part 61 is 30-600 micrometers. When the pitch in the major axis direction of the recesses 61 is a value within the above range, the viewing angle characteristics of the manufactured microlens substrate 1 and the contrast and brightness of the image projected by the microlens substrate 1 are particularly excellent. can do. Further, when the pitch in the major axis direction of the recess 61 is a value within the above range, it is possible to effectively prevent the occurrence of inconvenience such as moire when the manufactured microlens substrate 1 is used, Productivity of the microlens substrate 1 (member 6 with a recess) can be further increased.

  Moreover, it is preferable that the curvature radius of the recessed part 61 is 15-180 micrometers. When the radius of curvature of the recess 61 is a value within the above range, the viewing angle characteristics of the manufactured microlens substrate 1 can be made particularly excellent. In particular, both the horizontal and vertical viewing angle characteristics can be improved. The concave portion 61 may have a different radius of curvature in the minor axis direction and a radius of curvature in the major axis direction. In such a case, the radius of curvature in the major axis direction is a value within the above range. Preferably there is.

Moreover, it is preferable that the depth of the recessed part 61 is 10-180 micrometers. When the depth of the recess 61 is a value within the above range, the viewing angle characteristics of the manufactured microlens substrate 1 can be made particularly excellent.
The plurality of recesses 61 are arranged in a staggered pattern. By arranging the recesses 61 in this way, it is possible to effectively prevent inconveniences such as moire when the manufactured microlens substrate 1 is used. On the other hand, for example, if the concave portions are arranged in a square lattice shape or the like, it is difficult to sufficiently prevent the occurrence of inconvenience such as moire depending on the size of the concave portions (microlenses). In addition, when the concave portions are randomly arranged, depending on the size of the concave portion (microlens) or the like, it becomes difficult to sufficiently increase the occupancy ratio of the concave portions in the effective region where the concave portions are formed. It is difficult to sufficiently increase the transmittance (light utilization efficiency), and the obtained image may be dark.

  Further, as described above, the recesses 61 are arranged in a staggered pattern when the member 6 with recesses is viewed in plan view, but are adjacent to the first row composed of the plurality of recesses 61. The second row is preferably shifted by a half pitch in the vertical direction. As a result, when the manufactured microlens substrate 1 is used, it is possible to more effectively prevent the occurrence of moiré due to light interference and to make the viewing angle characteristics particularly excellent. it can.

  In the above description, the concave portion 61 is described as having substantially the same shape (dimension) and arrangement method as the microlens 21 except that the concave portion 61 has a concave-convex relationship. In the case where the constituent material of the substrate main body 2 is easily contracted (when the composition constituting the substrate main body 2 contracts due to solidification or the like), the microlens 21 and the recess 61 are considered in consideration of the contraction rate and the like. You may make it a shape (dimension), an occupation rate, etc. differ among these.

Next, the manufacturing method of a member with a recessed part is demonstrated, referring FIG. In practice, a large number of recesses (microlens formation recesses) are formed on the substrate. Here, in order to make the description easy to understand, a part of them is shown highlighted.
First, when manufacturing the member 6 with a recessed part, the board | substrate 7 is prepared.
The substrate 7 having a uniform thickness and having no deflection or scratches is preferably used. The substrate 7 is preferably one whose surface is cleaned by washing or the like.

<A1> A mask 8 having a large number of initial holes (openings) 81 is formed on the surface of the prepared substrate 7, and the back surface of the substrate 7 (the surface opposite to the surface on which the mask 8 is formed) A protective film 89 is formed (see a masking process, FIGS. 5A and 5B).
In particular, in the present embodiment, first, as shown in FIG. 5A, the back surface protective film 89 is formed on the back surface of the prepared substrate 7 and the mask forming film 4 is formed on the surface of the substrate 7 (mask). (Formation film forming step) Thereafter, as shown in FIG. 5B, the mask 8 is obtained by forming the initial hole 81 in the mask formation film 4 (initial hole formation step). The mask forming film 4 and the back surface protective film 89 can be formed simultaneously.

The mask forming film 4 is preferably capable of forming an initial hole 81 to be described later by laser light irradiation or the like and having resistance to etching in an etching process to be described later. In other words, the mask formation film 4 (mask 8) is preferably configured so that the etching rate is substantially equal to or lower than that of the substrate 7.
From this point of view, as a material constituting the mask forming film 4 (mask 8), for example, a metal such as Cr, Au, Ni, Ti, Pt, an alloy containing two or more selected from these, Examples thereof include oxides (metal oxides), silicon, and resins.
In addition, the mask forming film 4 (mask 8) may have, for example, a substantially uniform composition, or a laminated body having a plurality of different layers.

  As described above, the configuration of the mask forming film 4 (mask 8) is not particularly limited, but is a laminate having a layer mainly composed of chromium and a layer mainly composed of chromium oxide. Preferably there is. The mask forming film 4 having such a configuration can easily and reliably form an opening having a desired shape by irradiation with laser light as described later. The mask 8 obtained by using the mask forming film 4 has excellent stability with respect to etching solutions having various compositions (the substrate 7 can be more reliably protected in an etching process described later). . Further, when the substrate 7 is made of glass and the mask forming film 4 (mask 8) has the above-described structure, for example, in an etching process described later, two hydrogen atoms are used as an etching solution. A liquid containing ammonium fluoride can be suitably used. Since ammonium monohydrogen difluoride is not a poisonous deleterious substance, it is possible to prevent the human body and the environment during work more reliably. Further, the mask forming film 4 (mask 8) having the above-described configuration can relieve the internal stress of the mask efficiently, and is particularly excellent in adhesion with the substrate 7 (particularly, adhesion in the etching process). ing. For this reason, by using the mask forming film 4 (mask 8) having the above-described configuration, the concave portion 61 having a desired shape can be easily and reliably formed.

  The method for forming the mask forming film 4 is not particularly limited, but the mask forming film 4 (mask 8) is made of a metal material (including an alloy) such as chromium (Cr) or gold (Au) or a metal oxide (for example, chromium oxide). ), Or a composite material thereof (for example, a laminated body having a metal layer made of a metal material and a metal oxide layer made of a metal oxide, etc.) The film 4 can be suitably formed by, for example, a vapor deposition method or a sputtering method. When the mask forming film 4 (mask 8) is made of silicon, the mask forming film 4 can be suitably formed by, for example, a sputtering method or a CVD method.

  The thickness of the mask forming film 4 (mask 8) varies depending on the material constituting the mask forming film 4 (mask 8), but is preferably about 0.01 to 2.0 μm, preferably 0.01 to 0.3 μm. The degree is more preferable. If the thickness is less than the lower limit, the shape of the initial hole 81 formed in the initial hole forming step (opening forming step) described later may be distorted depending on the constituent material of the mask forming film 4 and the like. There is. In addition, when wet etching is performed in an etching process described later, the masked portion of the substrate 7 may not be sufficiently protected. On the other hand, if the upper limit value is exceeded, depending on the constituent material of the mask forming film 4 and the like, it becomes difficult to form the initial hole 81 that penetrates in the initial hole forming step described later, and the mask forming film 4 (mask Due to the internal stress of 8), the mask forming film 4 (mask 8) may be easily peeled off.

  The back surface protective film 89 is for protecting the back surface of the substrate 7 in the subsequent steps. By this back surface protective film 89, erosion, deterioration, etc. of the back surface of the substrate 7 are preferably prevented. The back surface protective film 89 has the same configuration as the mask forming film 4 (mask 8), for example. Therefore, the back surface protective film 89 can be provided in the same manner as the mask forming film 4 simultaneously with the formation of the mask forming film 4.

Next, as shown in FIG. 5B, a plurality of initial holes (openings) 81 are formed in the mask forming film 4 to obtain a mask 8 (initial hole forming step). The initial hole 81 formed in this step functions as a mask opening in the later-described etching.
A method for forming the initial hole 81 is not particularly limited, but a method using laser light irradiation is preferable. Thereby, the initial holes 81 having a desired shape arranged in a desired pattern can be easily and accurately formed. As a result, the shape, arrangement method, and the like of the recesses 61 can be controlled more reliably. In addition, by forming the initial hole 81 by laser irradiation, a member with a recess can be manufactured with high productivity. In particular, the concave portion can be easily formed even on a large-area substrate. Further, by forming the initial hole 81 in the mask forming film 4 by laser light irradiation, the opening (e.g., easier and less expensive than the case where the opening is formed in the resist film by a conventional photolithography method. An initial hole 81) can be formed.

In addition, when the initial hole 81 is formed by laser light irradiation, the type of laser light to be used is not particularly limited, but a ruby laser, a semiconductor laser, a YAG laser, a femtosecond laser, a glass laser, a YVO ₄ laser, a Ne- He laser, Ar laser, CO ₂ laser, excimer laser or the like may be mentioned. Moreover, you may use wavelengths, such as SHG of each laser, THG, and FHG.

  The shape and size of the initial hole 81 formed in this step is not particularly limited, but is substantially circular and the diameter is preferably 0.5 to 30 μm, more preferably 1.0 to 10 μm. Preferably, it is 1.5-5 micrometers. When the diameter of the initial hole 81 is a value within the above range, the concave portion 61 having the above-described shape can be reliably formed in the etching process described later. However, when the initial hole 81 has a flat shape such as a substantially elliptical shape, the length in the minor axis direction can be substituted for the value of the diameter. That is, when the initial hole 81 formed in this step has a flat shape, the width of the initial hole 81 (length in the minor axis direction) is not particularly limited, but is preferably 0.8 to 30 μm, More preferably, it is 1.0-10 micrometers, and it is still more preferable that it is 1.5-5 micrometers. When the width of the initial hole 81 is a value within the above range, the concave portion 61 having the above-described shape can be reliably formed in the etching process described later.

  In addition, when the initial hole 81 formed in this step is a flat shape, the length of the initial hole 81 (length in the major axis direction) is preferably 0.5 to 30 μm, and 1.0 to More preferably, it is 15 micrometers, and it is still more preferable that it is 1.5-10 micrometers. When the length of the initial hole 81 is a value within the above range, the concave portion 61 having the above-described shape can be more reliably formed in the etching process described later.

<A2> Next, as shown in FIG. 5C, the substrate 7 is etched using the mask 8 in which the initial holes 81 are formed, and a large number of recesses 61 are formed on the substrate 7 (etching step). .
The etching method is not particularly limited, and examples thereof include wet etching and dry etching. In the following description, a case where wet etching is used will be described as an example.

  By performing etching (wet etching) on the substrate 7 covered with the mask 8 in which the initial holes 81 are formed, as shown in FIG. 5C, the substrate 7 is a portion where the mask 8 does not exist ( A large number of recesses 61 are formed on the substrate 7 by etching from a portion corresponding to the initial hole 81 of the mask 8. As described above, since the initial holes 81 formed in the mask 8 are arranged in a staggered pattern (in a staggered pattern), the formed recesses 61 are formed in a staggered pattern (in a staggered pattern) on the surface of the substrate 7. It will be arranged.

Further, when the wet etching method is used, the concave portion 61 can be suitably formed. If, for example, an etching solution containing ammonium monohydrogen difluoride is used as the etching solution, the substrate 7 can be etched more selectively, and the recess 61 can be suitably formed.
When the mask 8 (mask forming film 4) is mainly composed of chromium or chromium oxide, the hydrofluoric acid-based etchant is particularly preferably a liquid containing ammonium monohydrogen difluoride. Since the ammonium hydrogen difluoride solution is not a poisonous and deleterious substance, it can prevent the influence on the human body and the environment during work. When ammonium monohydrogen difluoride is used as the etching solution, the etching solution may contain, for example, hydrogen peroxide and / or sulfuric acid. Thereby, an etching speed can be made faster.
Further, according to wet etching, it is possible to perform processing with a simpler apparatus than dry etching, and it is possible to perform processing on many substrates at once. Thereby, productivity improves and the member 6 with a recessed part can be provided cheaply.

<A3> Next, as shown in FIG. 5D, the mask 8 is removed (mask removal step). At this time, by removing the back surface protective film 89 along with the removal of the mask 8, the member 6 with a recess is obtained.
When the mask 8 is a laminated body having a layer mainly composed of chromium and a layer mainly composed of chromium oxide as described above, the removal of the mask 8 is, for example, ceric ammonium nitrate and perchlorine. The etching can be performed using a mixture containing an acid.

For example, you may perform a mold release process to the surface side in which the recessed part 61 of the member 6 with a recessed part is provided. Thereby, in the method of manufacturing the microlens substrate 1 described in detail later, the microlens 21 included in the substrate body 2 has a defect such as a chip (in particular, a defect near the boundary between the first region 22 and the second region 23). ) Can be easily removed, and as a result, defects in the microlens 21 can be prevented in the final microlens substrate 1. Examples of the mold release treatment include formation of a film composed of a material having releasability such as silicone resin such as alkylpolysiloxane, fluorine resin such as polytetrafluoroethylene, and hexamethyldisilazane ([(CH ₃ ) Surface treatment with a silylating agent such as ₃ Si] ₂ NH), surface treatment with a fluorine-based gas, and the like.

As described above, as shown in FIGS. 5D and 4, the member 6 with recesses in which a large number of recesses 61 are formed in a staggered pattern on the substrate 7 is obtained.
The method of forming the plurality of recesses 61 arranged in a staggered pattern on the substrate 7 is not particularly limited, but the method as described above (the initial holes 81 in the mask forming film 4 by laser irradiation). To obtain a mask 8, and then etching using the mask 8 to form the recess 61 on the substrate 7), the following effects are obtained.

That is, by forming the initial hole 81 in the mask forming film 4 by laser light irradiation, the opening (with a predetermined pattern) can be easily and inexpensively compared with the case where the opening is formed by a conventional photolithography method. A mask having initial holes 81) can be obtained. Thereby, productivity improves and the member 6 with a recessed part can be provided cheaply.
Further, according to the method as described above, it is possible to easily perform processing on a large substrate. When manufacturing a large substrate (a member with a recess, a lens substrate), it is not necessary to bond a plurality of substrates as in the prior art, and the seam of bonding can be eliminated. As a result, a high-quality large-sized substrate (a member with a recess, a lens substrate) can be manufactured at a low cost by a simple method.
Further, when the initial holes 81 are formed by laser irradiation, the shape, size, arrangement, and the like of the formed initial holes 81 can be managed easily and reliably.

Next, a method of manufacturing the microlens substrate 1 using the above-described member 6 with a recess will be described.
6 and 7 are schematic longitudinal sectional views showing an example of a manufacturing method of the microlens substrate shown in FIG. In the following description, the lower side in FIGS. 6 and 7 is referred to as “(light) incident side”, and the upper side is referred to as “(light) emission side”.

  <B1> First, as shown in FIG. 6 (a), a composition having a fluidity (the second composition) is formed on the surface on the side where the concavo-convex portion (honeycomb arrangement) of the boundary concavo-convex forming die 9 is formed. A region forming composition) 24 is applied, and a base material 26 is placed thereon, and the composition 24 is pressed by the flat plate (pressing member) 11 through the base material 26 (first pressing step). As the composition 24, for example, a softened resin material, an unpolymerized (uncured) resin material, or the like can be used.

  The boundary unevenness forming mold 9 includes unevenness arranged in a system (transferred positional relationship) corresponding to the array system of boundary unevenness. And the unevenness | corrugation which the type | mold 9 for boundary unevenness formation has is a boundary except the site | part corresponding to the recessed part of the boundary unevenness to be formed is a convex part, and the site | part corresponding to the convex part of the boundary unevenness to be formed is a recessed part. It has a shape corresponding to the unevenness (substantially the same shape except for the transferred shape) and dimensions. The boundary unevenness forming die 9 can be manufactured in the same manner as the member 6 with a recess described above except that the shape of the unevenness is different.

  Moreover, it is preferable that the base material 26 is comprised with the material which has a refractive index comparable as the composition 24 (composition 24 after solidification). The base material may be composed of any material, but is preferably the same acrylic system as the lens material. The base material 26 may be a relatively thick material or may be a film. Moreover, you may use what does not have flexibility substantially.

  In addition, you may perform the press by the flat plate 11 in the state which has arrange | positioned the spacer between the type | mold 9 for boundary uneven | corrugated formation, and the base material 26, for example. Thereby, the thickness of the 2nd field 23 formed can be controlled more certainly. Moreover, when using a spacer, when solidifying the composition 24, the spacer should just be distribute | arranged between the type | mold 9 for boundary uneven | corrugated formation, and the base material 26, and the timing which supplies a spacer is not specifically limited. For example, the composition 24 in which spacers are dispersed in advance as a resin to be applied may be used on the surface of the boundary unevenness forming mold 9 on which the uneven portions are formed, or the spacers are placed on the boundary unevenness forming mold 9. The composition 24 may be applied in a distributed state, or a spacer may be applied after the composition 24 is supplied.

<B2> Next, the composition 24 is solidified (including curing (polymerization)) to form the second region 23 including the microlenses 21 (first solidification step, see FIG. 6B). ).
When the composition 24 is solidified by curing (polymerization), examples of the method include irradiation with light such as ultraviolet rays, irradiation with electron beams, and heating.
Here, if necessary, in the composition 24 and / or the base material 26, for example, polystyrene beads, glass beads, organic cross-linked polymers and the like are mixed in advance as a diffusing material in order to diffuse the incident light from the light source. May be. Here, the diffusing material may be mixed in the composition 24 and / or the entire base material 26, or may be mixed only in part.

  <B3> Next, the boundary unevenness forming die 9 and the flat plate 11 are removed from the formed member of the second region 23 (pressing member / boundary unevenness forming die removing step, see FIG. 6C). The boundary unevenness forming mold 9 and the flat plate 11 thus removed can be repeatedly used for manufacturing the microlens substrate 1. Thereby, the stability of the quality of the microlens substrate 1 to be manufactured can be improved, and the manufacturing cost is advantageous.

  <B4> Next, as shown in FIG. 7 (d), on the surface on the side where the concave portion 61 of the concave portion member 6 for forming the microlens (staggered arrangement) serving as the first region is formed is fluid. A composition (first composition for forming a region) 27 is applied, and a member composed of the second region 23 obtained in the above-described step is placed thereon, and the second region 23 is formed. The composition 27 is pressed by the flat plate (pressing member) 11 through the member (second pressing step). As the composition 27, for example, a softened resin material, an unpolymerized (uncured) resin material in which a colorant is dispersed, or the like can be used.

  The pressing by the flat plate 11 may be performed, for example, in a state where a spacer is disposed between the member 6 with a recess and the member formed of the second region 23. Thereby, the thickness of the 1st field 22 formed can be controlled more certainly. Moreover, when using a spacer, when solidifying the composition 27, the spacer should just be arrange | positioned between the member 6 with a recessed part, and the 2nd area | region 23, and the timing which supplies a spacer is not specifically limited. For example, the composition 27 in which spacers are dispersed in advance as the resin to be applied may be used on the surface of the member 6 with recesses on the side where the recesses 61 are formed, or the spacers are arranged on the member 6 with recesses. The composition 27 may be applied, or a spacer may be applied after the composition 27 is supplied.

<B5> Next, the composition 27 is solidified (including curing (polymerization)) to form the first region 22 (second solidification step, see FIG. 7E).
In the case where the composition 27 is solidified by curing (polymerization), examples of the method include methods such as irradiation with light such as ultraviolet rays, irradiation with electron beams, and heating.
Here, in order to diffuse the incident light from the light source, for example, polystyrene beads, glass beads, organic cross-linked polymers, etc. may be mixed in advance as a diffusing material in the composition 27 as necessary. Here, the diffusing material may be mixed in the entire composition 27 or may be mixed only in part.

<B6> Next, the recessed member 6 and the flat plate 11 are removed from the formed first region 22 (pressing member / recessed substrate removing step, see FIG. 7F). Thereby, the microlens substrate 1 provided with the first region 22 and the second region 23 is obtained. The member 6 with concave portions and the flat plate 11 removed in this step can be repeatedly used for manufacturing the microlens substrate 1. Thereby, the stability of the quality of the microlens substrate 1 to be manufactured can be improved, and the manufacturing cost is advantageous.
According to the method as described above, a microlens substrate including the first region 22 and the second region 23 can be efficiently manufactured.

Next, a rear projector using the transmission screen will be described.
FIG. 8 is a diagram schematically showing the configuration of the rear projector of the present invention.
As shown in the figure, the rear projector 300 has a configuration in which a projection optical unit 310, a light guide mirror 320, and a transmissive screen 10 are arranged in a housing 340.
Since the rear projector 300 includes the transmissive screen 10 as described above, it is possible to obtain an image with high brightness and excellent contrast. Further, since the microlens substrate 1 (transmission type screen 10) as described above is provided, the viewing angle characteristics and the like are particularly excellent.

In particular, in the microlens substrate 1 described above, since the elliptical microlenses 21 are arranged in a staggered pattern (in a staggered pattern), the rear projector 300 is not particularly susceptible to problems such as moire.
As mentioned above, although this invention was demonstrated based on embodiment of illustration, this invention is not limited to these.

For example, each part of the lens substrate, the transmissive screen, and the rear projector can be replaced with any structure that can exhibit the same function.
In the embodiment described above, the plate-shaped (or film-shaped) member is used as the boundary unevenness forming mold and the recessed member. However, the boundary unevenness forming mold and the recessed member are as described above. For example, it may be a roll shape. Thereby, the productivity of the lens substrate can be made particularly excellent.

In the above-described embodiment, the colored portion (first region) has been described as being formed by molding a composition containing a colorant into a predetermined shape, but the colored portion (first region) The forming method is not limited to such a method. For example, the colored portion (first region) may be formed by manufacturing a member having a shape corresponding to the lens substrate (substrate body) and then staining the vicinity of the surface of the lens portion. In such a case, for example, the region to be the colored portion (first region) as the member is calibrated with a material that is easily dyed as compared with other regions, so that the colored portion (first region) is suitably obtained. Region) can be formed.
You may change the order of each process.

In the above-described embodiment, the coloring portion (first region) is described as being provided on the entire surface of the lens substrate on the light incident side, but the coloring portion (first region) is incident on the light. It may be provided only on a part of the surface side.
In the above-described embodiment, the microlens in the microlens substrate and the recess in the member with the recess have been described as having an elliptical shape when viewed in plan (flat shape). The shape may be any shape, and may be, for example, a circle, a substantially square, or a substantially hexagon.

  In the above-described embodiment, the microlenses in the microlens substrate and the concave portions in the member with concave portions are described as being arranged in a staggered manner, but the arrangement of the microlenses and concave portions may be any, For example, it may be arranged in a square lattice shape or a honeycomb shape. Moreover, the microlens and the recess may be formed randomly.

In the above-described embodiments, the transmission screen is described as including a microlens substrate (lens substrate) and a Fresnel lens. However, the transmission screen of the present invention does not necessarily include a Fresnel lens. May be. For example, the transmission screen of the present invention may be substantially constituted only by the lens substrate of the present invention.
In the above-described embodiment, the configuration including the microlens as the lens portion having a more desirable shape has been described from the viewpoint of the viewing angle. However, the lens portion (lens) configuring the lens substrate is not limited thereto. For example, a lenticular lens may be used. By using a lenticular lens, the manufacturing process of the lens portion can be simplified, and the productivity of the transmission screen can be improved. When a lenticular lens is used as the lens unit, a striped light shielding layer (black stripe) can be provided instead of the black matrix. Even in such a configuration, the same operation and effect as in the above-described embodiment can be obtained.

In the above description, the black matrix is directly formed on the surface of the substrate body. However, the black matrix is bonded to the substrate body through, for example, a base layer (adhesive layer). There may be.
Further, in the above-described embodiment, the composition is applied to the surface of the boundary unevenness forming mold and described as pressing with a flat plate through the base material. For example, the composition is applied to the surface of the base material, You may press this with the type | mold for boundary uneven | corrugated formation. Similarly, in the above-described embodiment, the composition is applied to the surface of the substrate with recesses and pressed with a flat plate via a member corresponding to the second region. For example, the second region The composition may be applied to the surface of the member corresponding to the above and pressed with a substrate with a recess.

  In addition, the lens substrate and the transmission type screen of the present invention may have a diffusion part and a diffusion plate having a function of diffusing light transmitted through the convex lens. With such a configuration, for example, the viewing angle characteristics of a transmissive screen and a rear projector can be further improved.

  In the above-described embodiments, the lens substrate is described as a member constituting a transmissive screen and a rear projector. However, the lens substrate of the present invention is applied to a transmissive screen and a rear projector. The present invention is not limited to this, and may be used for any purpose. For example, the lens-equipped substrate of the present invention may be applied to a constituent member of a liquid crystal light valve of a projection display device (front projector).

[Production of lens substrate and transmissive screen]
Example 1
First, a boundary unevenness forming mold provided with an uneven portion for forming boundary unevenness and a member with a recess provided with a recess for forming a microlens were manufactured.
Hereinafter, the manufacturing method of the boundary unevenness forming mold will be described, and then the manufacturing method of the member with concave portions will be described.

The boundary unevenness forming mold was manufactured as follows.
First, a soda glass substrate (absolute refractive index n ₂ : 1.50) having a width of 1.2 m × length of 0.7 m square and a thickness of 4.8 mm was prepared as a substrate.
This soda glass substrate was immersed in a cleaning solution containing 4 wt% ammonium monohydrogen difluoride and 8 wt% hydrogen peroxide and etched by 6 μm to clean the surface.
Thereafter, cleaning with pure water and drying using N ₂ gas (removal of pure water) were performed.

  Next, a chromium / chromium oxide laminate (a laminate in which chromium oxide was laminated on the outer surface side of chromium) was formed on the soda glass substrate by sputtering. That is, a mask forming film and a back surface protective film made of a chromium / chromium oxide laminate were formed on the surface of a soda glass substrate. The thickness of the chromium layer was 0.03 μm, and the thickness of the chromium oxide layer was 0.01 μm.

Next, laser processing was performed on the mask forming film to form a large number of initial holes in a range of 113 cm × 65 cm in the central portion of the mask forming film, thereby forming a mask.
The laser processing was performed using an excimer laser under the conditions of an energy density of 1.2 J / cm ² , a beam diameter of 2 μm at the processing point, and a scanning speed of 0.1 m / sec.
Thereby, substantially circular initial holes were formed in a pattern arranged in a honeycomb shape over the entire range of the mask forming film. The diameter of the initial hole was 2 μm.

Next, wet etching was performed on the soda glass substrate, and concave portions having a regular hexagonal shape when viewed in plan were formed on the soda glass substrate. The formed many recesses had substantially the same shape as each other. The formed recess had a length in the minor axis direction of 102 μm and a length in the major axis direction of 140 μm. Moreover, the curvature radius of the recessed part was 70 micrometers, and the depth of the recessed part was 70 micrometers. Moreover, the occupation rate of the recessed part in the effective area | region in which the recessed part was formed was 100%.
In the wet etching, an aqueous solution containing 4 wt% ammonium monohydrogen difluoride and 8 wt% hydrogen peroxide was used as an etchant, and the immersion time was 2.0 hours.

Next, the mask and the back surface protective film were removed by etching using a mixture of ceric ammonium nitrate and perchloric acid.
Next, cleaning with pure water and drying (removing pure water) using N ₂ gas were performed.
Thereafter, a gas phase surface treatment (silylation treatment) with hexamethyldisilazane was performed on the surface side of the substrate where the concave portions were formed, thereby forming a release treatment portion.
As a result, a boundary unevenness forming mold was obtained in which a large number of recesses for forming boundary unevenness were arranged in a honeycomb shape on a soda glass substrate. When the obtained boundary unevenness forming mold was viewed in plan, the proportion of the area occupied by the recesses in the effective region where the recesses were formed was 100%.

Next, the manufacturing method of a member with a recessed part is demonstrated.
First, a soda glass substrate (absolute refractive index n ₂ : 1.50) having a width of 1.2 m × length of 0.7 m square and a thickness of 4.8 mm was prepared as a substrate.
This soda glass substrate was immersed in a cleaning solution containing 4 wt% ammonium monohydrogen difluoride and 8 wt% hydrogen peroxide and etched by 6 μm to clean the surface.
Thereafter, cleaning with pure water and drying using N ₂ gas (removal of pure water) were performed.

  Next, a chromium / chromium oxide laminate (a laminate in which chromium oxide was laminated on the outer surface side of chromium) was formed on the soda glass substrate by sputtering. That is, a mask forming film and a back surface protective film made of a chromium / chromium oxide laminate were formed on the surface of a soda glass substrate. The thickness of the chromium layer was 0.03 μm, and the thickness of the chromium oxide layer was 0.01 μm.

Next, laser processing was performed on the mask forming film to form a large number of initial holes in a range of 113 cm × 65 cm in the central portion of the mask forming film, thereby forming a mask.
The laser processing was performed using an excimer laser under the conditions of an energy density of 1.2 J / cm ² , a beam diameter of 2 μm at the processing point, and a scanning speed of 0.1 m / sec.
Thereby, initial holes having a predetermined length were formed in a staggered pattern over the entire range of the mask forming film. The average width of the initial holes was 2 μm, and the average length was 2 μm.

Next, wet etching was performed on the soda glass substrate to form concave portions (recesses for forming microlenses) having a flat shape (substantially elliptical shape) when viewed in plan on the soda glass substrate. The formed many recesses had substantially the same shape as each other. The length (pitch) in the minor axis direction of the formed recess was 54 μm, the length in the major axis direction was 82 μm, the radius of curvature was 41 μm, and the depth was 41 μm. Moreover, the occupation rate of the recessed part in the effective area | region in which the recessed part was formed was 100%.
In the wet etching, an aqueous solution containing 4 wt% ammonium monohydrogen difluoride and 8 wt% hydrogen peroxide was used as an etchant, and the immersion time was 2.0 hours.

Next, the mask and the back surface protective film were removed by etching using a mixture of ceric ammonium nitrate and perchloric acid.
Next, cleaning with pure water and drying (removing pure water) using N ₂ gas were performed.
Thereafter, a gas phase surface treatment (silylation treatment) with hexamethyldisilazane was performed on the surface side of the substrate where the concave portions were formed, thereby forming a release treatment portion.
Thereby, the member with a recessed part in which many recessed parts for microlens formation were arranged on the soda glass substrate in zigzag form was obtained. When the obtained member with a recess was viewed in plan, the ratio of the area occupied by the recess in the effective region where the recess was formed was 100%.

Next, a composition composed of an unpolymerized (uncured) acrylic resin (an ultraviolet curable resin mainly composed of a methacrylate monomer) on the surface on which the concave portion of the boundary irregularity forming mold is formed A substrate (thickness: 2 mm) made of an acrylic resin was placed thereon. The refractive index (absolute refractive index) of the substrate was 1.53.
Next, the said composition was pressed through the base material with the flat plate comprised with soda glass. At this time, air was prevented from entering between the substrate and the composition.

  Thereafter, the composition was completely cured by irradiating the composition with ultraviolet rays while being pressed with a flat plate, thereby obtaining a member having a shape corresponding to the second region. This member had a convex portion corresponding to the concave portion of the boundary irregularity forming mold. Further, this member was not colored and was substantially transparent. The formed convex part had a length in the minor axis direction of 102 μm and a length in the major axis direction of 140 μm. Moreover, the curvature radius of the convex part was 70 micrometers, and the height of the convex part was 70 micrometers. Moreover, the occupation ratio of the convex part in the effective area | region in which the convex part is formed was 100%. Moreover, the refractive index (absolute refractive index) of the material which comprises the hardening part obtained by hardening was 1.557.

Next, the flat plate and the boundary unevenness forming mold were removed from the manufactured member.
Next, on the surface of the member with recesses on the side where the recesses are formed, a colorant (resin coloring dyeing solution) and an unpolymerized (uncured) acrylic resin (ultraviolet curing using a methacrylate monomer as main ingredients) And a member having a shape corresponding to the second region was placed thereon.

Next, the composition was pressed through the member with a flat plate made of soda glass. At this time, air was prevented from entering between the member and the composition.
Thereafter, the composition was completely cured by irradiating the composition with ultraviolet rays while being pressed with a flat plate, thereby forming a first region colored with a predetermined coloring concentration. The formed first member had a microlens having a shape corresponding to the concave portion of the concave substrate. The formed microlens had a flat shape (substantially elliptical shape), and had a length in the major axis direction of 82 μm, a radius of curvature of 41 μm, and a height of 41 μm. Further, the occupation ratio of the microlens in the effective region where the microlens is formed was 100%. In addition, the refractive index (absolute refractive index) of the material constituting the formed first region was 1.557. The density of the formed first region was 50% in terms of Y value (D65 / 2 ° field of view) as a screen.
Next, by removing the flat plate and the substrate with recesses, a microlens substrate as shown in FIGS. 1 and 2 was obtained.
A transmissive screen as shown in FIG. 3 was obtained by assembling the microlens substrate manufactured as described above and the Fresnel lens portion.

(Examples 2 to 6)
By changing the manufacturing conditions of the boundary unevenness forming mold and the substrate with recesses, the size and shape of the recesses of the boundary unevenness forming mold, the size, shape, occupation ratio, etc. of the recesses of the substrate with recesses are changed. In addition, a microlens substrate and a transmissive screen were manufactured in the same manner as in Example 1 except that the thickness and coloring density of the first region and the thickness of the second region were adjusted.

(Comparative Example 1)
The substrate with concave portions used in Example 1 was prepared.
Next, a composition composed of an unpolymerized (uncured) acrylic resin (an ultraviolet curable resin mainly composed of a methacrylate monomer) is formed on the surface of the member with a recess where the recess is formed. The base material (thickness: 2 mm) comprised with the acrylic resin was mounted on it. The refractive index (absolute refractive index) of the acrylic resin constituting the substrate was 1.53.

Next, the said composition was pressed through the base material with the flat plate comprised with soda glass. At this time, air was prevented from entering between the substrate and the composition.
Thereafter, the composition was completely cured by irradiating the composition with ultraviolet rays while being pressed with a flat plate. The cured part formed by curing had a microlens having a shape corresponding to the concave part of the substrate with concave parts. The formed microlens had a flat shape (substantially elliptical shape), and had a length in the major axis direction of 82 μm, a radius of curvature of 41 μm, and a height of 41 μm. Further, the occupation ratio of the microlens in the effective region where the microlens is formed was 100%. In addition, the refractive index (absolute refractive index) of the material constituting the formed first region was 1.557.
Next, the microlens substrate was obtained by removing the flat plate and the substrate with recesses. This microlens substrate was not colored and was substantially transparent.
By assembling the microlens substrate manufactured as described above and the Fresnel lens portion, a transmissive screen as shown in FIG. 3 was obtained in the same manner as in Example 1.

(Comparative Example 2)
A microlens substrate in the same manner as in Example 1, except that a substrate with a recess that forms the shape of the first region was used as the substrate that forms the shape of the unevenness (boundary unevenness) at the boundary with the second region, A transmission screen was produced. That is, the shape of the unevenness (boundary unevenness) at the boundary between the first region and the second region is the same as the surface shape of the microlens, and the pitch of the boundary unevenness is the same as the pitch of the microlens ( A microlens substrate and a transmissive screen were manufactured in the same manner as in Example 1 except for those shown in FIGS. In addition, although the pitch, arrangement | positioning, and curvature of a micro lens are the same as the said Example 1, the type | mold with an occupation rate of 65% and a lens diameter of 50 micrometers was obtained by adjusting etching time.

(Comparative Example 3)
By changing the manufacturing conditions of the boundary unevenness forming mold, as shown in Table 1, except that the pitch of the recesses of the boundary unevenness forming mold is smaller than the pitch of the recesses of the substrate with the recesses In the same manner as in Example 1, a microlens substrate and a transmission screen were manufactured (see FIG. 12).

(Comparative Example 4)
A microlens substrate and a transmissive screen were manufactured in the same manner as in Example 1 except that a flat plate having a flat surface was used instead of the boundary unevenness forming mold (see FIG. 13). In addition, as a flat plate in place of the mold for forming the boundary irregularities, a plate (having a release treatment part) whose entire surface was subjected to gas phase surface treatment (silylation treatment) with hexamethyldisilazane was used. .
Table 1 summarizes the configuration of the microlens substrate for each of the examples and comparative examples. In Table 1, the acrylic resin is represented by Ac, the colorant is represented by P, and the styrene resin is represented by As. In Table 1, the column “average thickness” shows the value of the average thickness of the first region in the vicinity of the top of the microlens.

[Evaluation of contrast]
Contrast evaluation was performed on the transmissive screens produced in the respective Examples and Comparative Examples. Contrast is the amount of increase in the front luminance of white display (white luminance) LW (cd / m ² ) when 410 lx all white light is incident in the dark room and the front luminance of black display when the light source is completely turned off in the bright room. (Amount of increase in black luminance) The ratio to LB (cd / m ² ), LW / LB, was determined and evaluated according to the following four criteria. The bright room was measured in a room with an external light illuminance of 185 lx (bright room). A luminance meter BM-7 manufactured by Topcon was used for the luminance measurement.
A: Contrast 250 or more.
○: Contrast 200-250.
(Triangle | delta): Contrast 150-200.
X: Contrast 150 or less.

[Production of rear projector]
Rear projectors as shown in FIG. 8 were produced using the transmissive screens of the respective Examples and Comparative Examples.
[Evaluation of uneven color]
The Y value (D65 / 2 ° field of view) of the transmissive screens of the rear projectors of each of the examples and comparative examples was measured in 20 planes, and the difference ΔT (Y) between the maximum value and the minimum value of the transmittance was measured. %) Was defined as color unevenness, and the occurrence of color unevenness was evaluated according to the following four criteria.
A: ΔT (Y) (%) less than 3%. No color unevenness is observed.
○: ΔT (Y) (%) 3 to 5%. There is almost no color unevenness.
Δ: ΔT (Y) (%) 5 to 10%. Slight color unevenness is observed.
X: ΔT (Y) (%) more than 10%. Color unevenness is noticeable.

[Evaluation of diffracted light and moire]
Sample images were displayed on the transmissive screens of the rear projectors of the examples and comparative examples. The displayed images were evaluated for the occurrence of diffracted light and moiré according to the following four criteria.
A: Diffraction light and moire are not recognized at all.
○: Diffracted light and moire are hardly recognized.
Δ: Slightly diffracted light and moire are observed.
X: Diffracted light and moire are remarkably recognized.

[Evaluation of viewing angle symmetry]
The luminance of the screen was measured from the direction of 45 ° to the left and right of the normal to the screen, and the difference in luminance was evaluated according to the following four criteria.
A: The difference in luminance is 5 or less.
○: The difference in luminance is 5-15.
(Triangle | delta): The difference of a brightness | luminance is 15-25.
X: The difference in luminance is 25 or more.

[Evaluation of long-term stability]
The produced transmission type screen was installed immediately before the light emitting part of the projection optical unit of the rear projector that radiates 450 lx light, and the long-term stability was evaluated at an accelerated rate by placing it in a 60 ° C. environment.
The difference in transmittance (change amount ΔT (Y)) or the change in appearance (peeling, floating, deformation, etc.) around 10 hours from the start of light irradiation is regarded as deterioration or unevenness of the transmission screen, and is divided into the following four stages. Evaluation was made according to criteria.
(Double-circle): Deterioration and nonuniformity are not recognized at all. Alternatively, the change amount ΔT (Y) is less than 3%.
○: Deterioration and unevenness are hardly observed. Or change amount (DELTA) T (Y) 3 to 5%.
Δ: Slight deterioration or unevenness is observed. Alternatively, the change amount ΔT (Y) is 5 to 10%.
X: Deterioration and unevenness are noticeable. Or the amount of change ΔT (Y) exceeds 10%.
These results are summarized in Table 2.

As is clear from Table 2, the present invention provided excellent contrast, and was excellent in viewing angle characteristics and long-term stability in each direction. In the present invention, an excellent image without color unevenness could be displayed. That is, in the present invention, an excellent image can be stably displayed over a long period of time.
On the other hand, in the comparative example, a satisfactory result was not obtained. In particular, in Comparative Example 1 having no colored portion, the contrast was particularly low. Further, in Comparative Example 2 in which the shape of the boundary unevenness is the same as the surface shape of the microlens, and the pitch of the boundary unevenness is the same as the pitch of the microlens, the average thickness of the colored layer is large and the boundary unevenness is small. Structurally, the structure was almost the same as that of Comparative Example 4, and as a result, the characteristics were the same as those of Comparative Example 4.

It is a typical longitudinal section showing a suitable embodiment of a lens substrate (micro lens substrate) of the present invention. FIG. 2 is a schematic plan view of the lens substrate shown in FIG. 1. It is a typical longitudinal cross-sectional view which shows suitable embodiment of the transmission type screen of this invention provided with the lens board | substrate (microlens board | substrate) shown in FIG. It is a typical longitudinal section showing a member with a crevice used for manufacture of a micro lens substrate. It is a typical longitudinal cross-sectional view which shows the manufacturing method of the member with a recessed part shown in FIG. It is a typical longitudinal cross-sectional view which shows an example of the manufacturing method of the lens board | substrate (micro lens board | substrate) shown in FIG. It is a typical longitudinal cross-sectional view which shows an example of the manufacturing method of the lens board | substrate (micro lens board | substrate) shown in FIG. It is a figure which shows typically the rear type projector to which the transmission type screen of this invention is applied. It is a typical longitudinal cross-sectional view for demonstrating the lens board | substrate of a comparative example. It is a typical longitudinal cross-sectional view for demonstrating the lens board | substrate of a comparative example. It is a typical longitudinal cross-sectional view for demonstrating the lens board | substrate of a comparative example. It is a typical longitudinal cross-sectional view for demonstrating the lens board | substrate of a comparative example. It is a typical longitudinal cross-sectional view for demonstrating the lens board | substrate of a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Micro lens board | substrate (lens board | substrate) 2 ... Board | substrate main body 21 ... Micro lens (lens part) 211 ... Center 22 ... 1st area | region (colored part) 23 ... 2nd area | region (non-colored part) 24 ... Composition ( Second region forming composition) 26 ... base material 27 ... composition (first region forming composition) 28 ... first row 29 ... second row 4 ... mask forming film 5 ... Fresnel lens portion DESCRIPTION OF SYMBOLS 51 ... Fresnel lens 6 ... Member with a recessed part (Member with a recessed part for microlens formation) 61 ... Recessed 7 ... Substrate 8 ... Mask 81 ... Initial hole 89 ... Back surface protective film 9 ... Boundary unevenness forming type 10 ... Transmission type screen 11 ... Flat plate (pressing member) 300 ... Rear projector 310 ... Projection optical unit 320 ... Light guide mirror 340 ... Case

Claims (16)

A lens substrate having a lens portion as a plurality of convex lenses,
A first region colored at a predetermined density provided near the surface of the lens unit;
A color density lower than that of the first region, and a second region provided so as to be in contact with the first region,
The boundary between the first region and the second region is uneven,
When the average pitch of the irregularities at the boundary between the first region and the second region is P _B [μm] and the average pitch of the lens portions is P _L [μm], the relationship of P _B > P _L is established. A lens substrate characterized by satisfaction.   The lens substrate according to claim 1, wherein the second region is substantially uncolored.   The lens substrate according to claim 1, wherein the lens unit is a microlens. The lens substrate according to claim 1, wherein the P _B is 30 to 600 μm. The lens substrate according to claim 1, wherein an average pitch P _L [μm] of the lens portions is 25 to 360 μm. 6. The lens substrate according to claim 1, wherein the P _B and the P _L satisfy a relationship of 1.2 ≦ P _B / P _L ≦ 24. The lens substrate according to claim 1, wherein the P _B and the P _L satisfy a relationship of 5.0 ≦ P _B −P _L ≦ 575.   8. The lens substrate according to claim 1, wherein an average thickness of the first region in the vicinity of a top portion of the lens portion is 10 to 400 μm.   9. The lens substrate according to claim 1, wherein a difference in level of unevenness at a boundary between the first region and the second region is 15 to 360 μm.   10. The lens substrate according to claim 1, wherein the coloring density of the first region is 20 to 95% in terms of a Y value (D65 / 2 ° field of view).   The lens substrate according to any one of claims 1 to 10, wherein the lens portions are arranged in a staggered arrangement, and the arrangement of irregularities at the boundary between the first region and the second region is a honeycomb arrangement. A method for producing the lens substrate according to claim 1, comprising:
Forming a second region on the substrate using a mold;
A process for producing a lens substrate, comprising: applying a composition containing a colorant and a resin material on the second region and forming the first region by molding the composition into a predetermined shape. Method.   The method of manufacturing a lens substrate according to claim 11, wherein the second region is formed so that a surface shape thereof is a microlens shape.   A transmissive screen comprising the lens substrate according to claim 1. A Fresnel lens part having a Fresnel lens formed on the light exit side;
A transmissive screen comprising: the lens substrate according to claim 1 disposed on a light emission side of the Fresnel lens portion. A rear projector comprising the transmissive screen according to claim 14.

Images