JP2007086375A - Light diffusing member and transmission type screen using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light diffusing member which is excellent respectively in contrast and resolution of a rear projection type display, and to provide a transmission type screen provided with the light diffusing member. <P>SOLUTION: The light diffusing member 50 comprises: a sheet-like lenticular lens part 10 in which a large number of convex cylindrical lenses 5 are formed in parallel to one another with a constant pitch P<SB>c</SB>on one side surface in the thickness direction; a light shielding pattern 20 which is arranged in a stripe shape on the other surface 10a of the lenticular lens part 10; a transmissive resin layer 30 formed so as to cover the other surface 10a and the light shielding pattern 20; and a light diffusion part which is formed by a transmissive resin 32 with light diffusing material 34 dispersed therein and is joined to the transmissive resin layer 30. When the refractive index of the convex cylindrical lenses 5 is n<SB>c</SB>, the proportion of the width of a stripe-shaped light shielding part 15 to a pitch Pc is A and the thickness of the transmissive resin layer 30 is T, the thickness T is selected so as to satisfy the following relation: T>[P<SB>c</SB>×(1-A)]/[2×(2+A)×tan(sin<SP>-1</SP>(1/n<SB>c</SB>))]. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light diffusing member and a transmission screen using the same, and more specifically, a light diffusing material is dispersed on one side of a lenticular lens portion having a large number of convex cylindrical lenses on one surface side in the thickness direction. The present invention relates to a light diffusing member in which a light diffusing portion made of a translucent resin is bonded via a light shielding pattern and a translucent resin layer, and a transmissive screen using the light diffusing member.

  Today, large-screen displays such as liquid crystal displays, projection displays, and plasma displays are prevalent in ordinary homes. Large screen displays are often purchased with the assumption that multiple people watch videos (images), so that each person can enjoy high-quality video even when watching multiple videos (images). High viewing angle characteristics are required. For this reason, for example, in a rear projection display, a transmissive screen provided with a light diffusing member is used in order to improve the viewing angle characteristics in the horizontal direction (meaning the horizontal direction of the screen; the same applies hereinafter).

  Various light diffusing members have been proposed for use in transmissive screens. One of them is a large number of convex cylindrical lenses (cylindrical whose refractive surface is convex on one surface side in the thickness direction). A lens, which is the same hereinafter) formed at a constant pitch, and the other surface in the thickness direction is formed into a flat surface, and formed on the other surface of the lenticular lens portion. There is a type of light diffusing member provided with a light shielding pattern composed of a large number of light shielding portions.

  The light diffusing member of the above type is combined with a Fresnel lens sheet to constitute a transmissive screen. At this time, the Fresnel lens sheet is disposed closer to the image light source than the light diffusing member in the projection optical system of the rear projection display, and the image light projected in a divergent light state is substantially parallel light (including parallel light). It is used in the meaning, and the same shall apply hereinafter) to be incident on the light diffusing member. In the light diffusing member, the longitudinal direction of each convex cylindrical lens is in the vertical direction (which means the vertical direction of the screen; the same applies hereinafter), and the refractive surface of each convex cylindrical lens is in the direction toward the Fresnel lens sheet side. Arranged to diffuse the image light in a substantially parallel light state emitted from the Fresnel lens sheet in the arrangement direction of the convex cylindrical lenses. As a result, the viewing angle characteristics in the horizontal direction of the rear projection type display are good. In addition, the light shielding pattern formed on the other surface of the light diffusing member functions to prevent external light from being reflected on the transmissive screen and improve the contrast of the image.

  In such a transmission screen, in order to improve not only the horizontal viewing angle characteristics but also the vertical viewing angle characteristics in the rear projection type display, resin beads or glass beads are provided on the lenticular lens portion of the light diffusing member. It is generally performed to include a light diffusing material such as.

  By the way, as a light source, a three-tube CRT light source is generally used, but LCD (Liquid Crystal Display) and DLP (Digital Light Processing) are used in response to recent demands for digitalization, high definition, and compactness. A single-tube light source (hereinafter referred to as “single light source” in the present application) has been used. When this single light source is used, there is an advantage that the still image and the character display become clearer, brighter and wider in angle of view due to the pixel display which is the feature. However, when a pixel display type single light source is used, moire occurs between the pixel and the convex cylindrical lens unless the pitch of the convex cylindrical lens of the light diffusing member constituting the transmission screen is set to a fine pitch. There was a problem of doing.

In order to solve the above problem, the convex cylindrical lens of the lenticular lens portion may be narrow pitch, but in the extrusion molding which is a conventional manufacturing method of the light diffusing member, the thickness of the lenticular lens portion must be reduced, As a result, the content of the light diffusing material for improving the viewing angle characteristics is limited, and a sufficient effect may not be obtained.
Japanese Patent No. 2825887 (Fig. 3)

  In particular, in view of the above situation where a sufficient light diffusing material cannot be contained in the lenticular lens portion as in the case of using a single light source, the present inventor A study was made to improve the viewing angle characteristics by arranging a light diffusing part containing a diffusing material in a resin layer or resin film on the observation side of the lenticular lens part. However, in a transmissive screen using such a light diffusing member, the image light is returned to the lenticular lens portion by the backscatter and becomes stray light, and the stray light is emitted from the light-exiting surface on the observation side to reduce contrast. It sometimes caused a decrease in resolution. The “back scatter” is a phenomenon in which a part of light incident on the light diffusing portion from the lenticular lens portion is reflected by the light diffusing material in the light diffusing portion and returns to the lenticular lens portion side.

  FIG. 2 is a schematic diagram showing that return light from the backscatter becomes stray light. As can be seen from FIG. 2, part of the light that has been backscattered and returned to the lenticular lens part is totally reflected at the interface between the refractive surface of the convex cylindrical lens and the medium (air) outside thereof, and again from the lenticular lens part. This is retroreflected light that is emitted to the observation side. When such retroreflected light is generated, there arises a problem that the resolution of the rear projection display is lowered or the contrast is lowered. In addition, any convex cylindrical lens constituting the lenticular lens portion (in FIG. 2, Of the light collected by the convex cylindrical lens 5a), most of the light that becomes retroreflected light is back-scattered with a light diffusing material after the back diffusion with the light diffusing member due to the configuration of the light diffusing member. In many cases, the light exits from the light exit surface on the observation side after being totally reflected at the interface between the refractive surfaces of the cylindrical lenses 5b and 5c and the medium outside thereof.

  The present invention has been made in view of the above circumstances, and an object thereof is a light diffusing member capable of improving the contrast and resolution of a rear projection display, and a transmissive screen including the light diffusing member. Is to provide.

The light diffusing member of the present invention for solving the above problems includes a sheet-like lenticular lens portion in which a large number of convex cylindrical lenses are formed in parallel with each other at a constant pitch _Pc on one surface side in the thickness direction. A light-shielding pattern comprising a plurality of light-shielding portions arranged in a stripe pattern on the other surface in the thickness direction of the lenticular lens portion, and a translucent resin layer formed so as to cover the other surface and the light-shielding pattern When, a light diffusing member having a light diffusing portion that the light diffusing member is bonded to the transparent resin layer is formed by dispersing the translucent resin, the refractive index of the convex cylindrical lens n _c The thickness T satisfies the following formula (I), where A is the ratio of the width of the stripe-shaped light shielding portion to the pitch P _c and T is the thickness of the translucent resin layer. And (below The light diffusing member is sometimes referred to as “light diffusing member I”.

Here, the “refractive index” means a refractive index when the wavelength of the measuring light is 589 nm, and is represented by a value measured with an Abbe refractometer using a 589 nm filter. Further, the “thickness of the translucent resin layer” refers to a translucent light whose reference plane is an emission surface when light incident on a convex cylindrical lens and collected by the convex cylindrical lens is emitted from the lenticular lens portion. Means the thickness of the conductive resin layer. The units of the pitch _Pc and the thickness T are not limited as long as they are the same.

According to this light diffusing member I, the thickness T of the translucent resin layer satisfies the above formula (I) in the relationship between the pitch P _c of the convex cylindrical lens and the ratio A of the light shielding portion width to the pitch P _c . Therefore, even if the light back-scattered by the light diffusing part is totally reflected at the interface between the refractive surface of the adjacent convex cylindrical lens and the medium (air) outside thereof and travels toward the observation side (the other surface side) The light is blocked by the light shielding portion formed at a ratio A with respect to the pitch _Pc of the convex cylindrical lens. As a result, the light generated based on the back scatter is effectively blocked by the light shielding part, so that the light that exits to the observation side as retroreflected light can be reduced, and the reduction in contrast and resolution are suppressed. Can do.

  In addition, since the light-diffusion member of this invention has a lenticular lens part, the substantially parallel light (including parallel light. The following is the same) incident on the lenticular lens part from the light source side which is said one surface side is each convex cylindrical. The lens can be diffused in the lens arrangement direction (usually in the horizontal direction) and has the light diffusing unit. Therefore, the substantially parallel light incident on the lenticular lens unit is different from the direction in which the convex cylindrical lenses are arranged (usually normal). Can also be diffused in the vertical direction. If such a light diffusing member I is combined with a Fresnel lens sheet to constitute a transmissive screen, a rear projection display having excellent viewing angle characteristics and good contrast and resolution can be constructed.

  In the light diffusing member I of the present invention, the thickness T preferably satisfies the following formula (II) (hereinafter, this light diffusing member may be referred to as “light diffusing member II”).

According to the light diffusing member II, the thickness T of the translucent resin layer satisfies the above formula (II) in the relationship between the pitch _Pc of the convex cylindrical lens and the ratio A of the light shielding portion width to the pitch _Pc . Therefore, the light generated based on the backscatter can be further blocked by the light blocking portion. As a result, it is possible to reduce the light emitted to the observation side as retroreflected light, and to further suppress the decrease in contrast and the decrease in resolution.

  In any of the light diffusing members I and II of the present invention, the translucent resin layer is a transparent resin layer that does not include the light diffusing member (hereinafter, this light diffusing member is referred to as “light diffusing member III”). Is preferred).

According to this light diffusing member III, since the translucent resin layer is a transparent resin layer not including the light diffusing member, backscattering in the translucent resin layer does not occur, and the thickness T of the translucent resin layer is reduced. The effect based on the relationship of the above formulas (I) and (II) expressed by the pitch P _c of the convex cylindrical lens and the ratio A of the light shielding portion width to the pitch P _c becomes more effective. As a result, it is possible to reduce the light emitted to the observation side as retroreflected light, and to further suppress the decrease in contrast and the decrease in resolution.

  Any of the light diffusing members I to III of the present invention further includes an antistatic layer as the outermost component on the light diffusing portion side (hereinafter, this light diffusing member may be referred to as “light diffusing member IV”). ), Further having an antireflection layer as the outermost component on the light diffusion portion side (hereinafter, this light diffusion member may be referred to as “light diffusion member V”), or on the light diffusion portion side. It is preferable to further have an antiglare layer as the outermost component (hereinafter, this light diffusing member may be referred to as “light diffusing member VI”).

  In the light diffusing member IV, dust adhesion is suppressed by the antistatic layer, so that it is easy to keep the optical characteristics in a good state even if the frequency of cleaning is low. In the light diffusing member V, since reflection of external light is suppressed by the antireflection layer, it is possible to suppress the reflected light from being superimposed on the diffused light by the light diffusing member V. Further, according to the light diffusing member VI, since the light diffusing member VI has an antiglare layer, it is possible to suppress glare when visually recognized, and as a result, the light diffusing member VI is configured using the light diffusing member VI. Further, the glare on the display surface of the transmissive screen can be suppressed.

  The transmissive screen of the present invention for solving the above-described problems includes any one of the light diffusing members I to VI of the present invention described above, and a Fresnel lens disposed outside the refractive surface of the convex cylindrical lens in the light diffusing member. And a sheet.

  According to this transmissive screen, the image light can be diffused by the light diffusing member of the present invention after being converted into substantially parallel light by the Fresnel lens sheet, so that the contrast and resolution of the rear projection display can be improved. can do.

As described above, according to the light diffusing member of the present invention, the light backscattered by the light diffusing portion is totally reflected and observed at the interface between the refractive surface of the adjacent convex cylindrical lens and the medium (air) outside thereof. Even if it goes to the side (the other surface side), the light is blocked by the light shielding portion formed at a ratio of A to the pitch _Pc of the convex cylindrical lens, so it is generated based on the backscatter. Light is blocked by the light blocking portion. As a result, it is possible to reduce the light emitted to the observation side as retroreflected light, and to suppress the decrease in contrast and the decrease in resolution.

  If such a light diffusing member is combined with a Fresnel lens sheet to constitute a transmissive screen, a rear projection display having excellent viewing angle characteristics and good contrast and resolution can be constructed.

  Hereinafter, the respective forms of the light diffusing member and the transmissive screen of the present invention will be described with reference to the drawings as appropriate.

(Light diffusion member: 1st form)
FIG. 1 is a cross-sectional view schematically showing the basic structure of the light diffusing member of the present invention. The illustrated light diffusing member 50 includes a lenticular lens unit 10, a light shielding pattern 20 provided on the lenticular lens unit 10, a translucent resin layer 30 covering the light shielding pattern 20, and light bonded to the translucent resin layer 30. And a diffusion unit 40. Hereinafter, the basic structure and features of the light diffusing member of the present invention will be described with reference to the light diffusing member 50.

The lenticular lens portion 10 is a sheet-like object in which a large number of convex cylindrical lenses 5 are formed in parallel to each other at a constant pitch _Pc on one surface side in the thickness direction, and the other surface in the thickness direction. 10a (hereinafter referred to as “back surface 10a”) is formed into a flat surface. When the light diffusing member 50 is used as a transmissive screen material, the above pitch is used from the viewpoint of preventing moiré with a single tube type light source using LCD (Liquid Crystal Display) or DLP (Digital Light Processing). it is preferred to select a P _c in the range of about 50 to 500 [mu] m, it is more preferably selected within a range of about 50 to 300 [mu] m. The pitch _Pc is preferably set to ¼ or less of the pixel pitch in the matrix video source. The maximum thickness of the lenticular lens portion 10 may vary depending on the pitch _{P c,} usually suitably selected within a range of 1.0 to 1.5 times the pitch _{P c.}

  From the viewpoint of obtaining a transmission screen with high image quality in front of the screen, each convex cylindrical lens 5 has a light condensing point incident near the optical axis OA from the refractive surface side incident on the end in the width direction. It is preferable that the aspherical lens is farther than the light condensing point. In particular, the light condensing point of light incident near the optical axis OA is outside the lenticular lens unit 10 and is incident on the end in the width direction. It is preferable that the condensing point is an aspherical lens on the back surface 10a.

  Such a lenticular lens unit 10 is formed, for example, by molding a transparent resin having a refractive index of about 1.45 to 1.60 into a desired shape by a method such as extrusion molding or mold molding involving irradiation with ultraviolet rays or electron beams. Can be obtained. To obtain a highly practical light diffusion member 50, transparent resins such as acrylic resins, polycarbonate resins, vinyl chloride resins, styrene resins, cellulose resins, cycloolefin resins, acrylic / styrene copolymer resins, etc. Alternatively, it is preferable that the lenticular lens portion 10 is formed of ultraviolet rays such as urethane, epoxy, or polyester, or an electron beam curable transparent resin.

Shielding pattern 20 is for a number of the light-shielding portion 15 is disposed in parallel stripes each other at a constant pitch P _S, symmetry axis the optical axis OA around the optical axis OA of the individual convex cylindrical lenses 5 A belt-like light transmission portion is defined. The pitch P _S of the light-shielding portion 15 of the light-shielding pattern 20, the pitch P _c of the convex cylindrical lens 5 in the lenticular lens portion 10 is the same value each other.

  The height H of each light shielding part 15 is substantially constant over the whole, and the variation in the height H between the light shielding parts 15 can be ignored. This height H can be appropriately selected within a range of about 1 to 20 μm. Further, the width of each light shielding portion 15 is substantially constant.

  The light shielding portion 15 is disposed outside the optical path when light parallel or substantially parallel to the optical axis OA of each convex cylindrical lens 5 is incident on the refractive surface of the convex cylindrical lens 5. In order to obtain a transmissive screen with high image contrast using the light diffusing member 50, each light shielding portion occupies at least the area corresponding to the display area on the transmissive screen among the back surface 10 a of the lenticular lens portion 10. The ratio of the total area of 15 in plan view is preferably selected as appropriate within a range of about 40 to 90%, and more preferably selected within a range of about 60 to 85%. If the ratio is less than 40%, the contrast of the image tends to be low, and if it exceeds 90%, part of the image light is likely to be blocked by the light shielding portion 15 when assembled into a projection display, and as a result, Spots are likely to occur.

  Each light shielding portion 15 is made of, for example, black ink, black toner, or the like using a normal printing method such as an inkjet method, an electrostatic printing method, a gravure printing method, an offset printing method, a silk printing method, a wiping method, a transfer method, or the like. It can be formed by a method. Further, the light shielding portion 15 is also formed at a desired position by forming a black layer on the entire back surface 10a of the lenticular lens portion 10 and selectively heating and scattering the black layer at unnecessary portions by irradiating infrared light. can do. Prior to the formation of the light shielding portion 15, for example, a photocatalytic reaction is used to selectively change the wettability of the back surface 10 a so that the region of the light shielding portion 15 where the raw material has high wettability corresponds to the shape and size of the light shielding pattern 20. If formed in this manner, each light shielding portion 15 is easily formed at a desired position.

The translucent resin layer 30 is a transparent adhesive layer for bonding the light diffusing portion 40 to the lenticular lens portion 10, and is particularly preferably a transparent resin layer not including a light diffusing member. The translucent resin layer that does not include the light diffusing member does not cause backscattering of the image light from the light source, and the light shielding portion with respect to the thickness T of the translucent resin layer, the pitch _{Pc of the} convex cylindrical lens, and the pitch _Pc . The effect based on the relationship of the above formulas (I) and (II) expressed by the width ratio A can be made more effective. Details of the relationship between the above formulas (I) and (II) will be described later.

  Such a translucent resin layer 30 is, for example, a photocurable resin composition that is cured by irradiating light in a predetermined wavelength region to become a transparent resin, or a transparent resin that is cured by irradiating an electron beam. An electron beam curable resin composition, or a two-component transparent adhesive, a transparent adhesive, or the like can be used as a raw material. The kind of raw material of the translucent resin layer 30 is preferably selected as appropriate so that the total light transmittance of visible light in the translucent resin layer 30 is about 70% or more, usually about 90%. In order to further improve the contrast of the image on the transmission screen using the light diffusing member 50, the above raw material is added with a black dye so that the total light transmittance of visible light is 30% or more. The light resin layer 30 may be formed.

  The light diffusing unit 40 forms a transmissive screen using the light diffusing member 50, and when this transmissive screen is used as a screen of a rear projection display, only the viewing angle characteristics in the horizontal direction of the rear projection display can be obtained. It is a member for improving the viewing angle characteristics in the vertical direction, and is formed of a composite material in which a large number of light diffusing materials 34 such as resin beads and glass beads are dispersed in a translucent resin 32 as a matrix material. .

  Such a light diffusing portion 40 uses, for example, a thermoplastic resin, a photocurable resin composition, an electron beam curable resin composition or the like as a matrix raw material, and the light diffusing material 34 is dispersed in the raw material. It can be formed by forming an uncured layer by a method such as extrusion molding or coating, and then curing the uncured layer by a method such as cooling, light irradiation, or electron beam irradiation. The content of the light diffusing material 34 in the light diffusing portion 40 is about 0.01 to 10% by mass depending on the degree of light diffusion required for the light diffusing portion 40, the type and size of the light diffusing material 34, and the like. It can be selected appropriately within the range.

When the light diffusing member 50 and a Fresnel lens sheet having no light diffusing function are combined to form a transmissive screen, the degree of light diffusion by the light diffusing unit 40 is determined by the diffusion half-value angle being α ₂₅ , diffusion 1 When the / 3 value angle is represented by β ₂₅ and the diffusion 1/10 value angle is represented by γ ₂₅ , α ₂₅ > 3, β ₂₅ > 5, and γ ₂₅ > 6 are preferable, and α ₂₅ > 5, β ₂₅ More preferably,> 6 and γ ₂₅ > 9.

Further, when the light diffusing member 50 and a Fresnel lens sheet having a light diffusing function are combined to form a transmission type screen, the diffusion half-value angle in the Fresnel lens sheet is α _FL and the diffusion 1/3 value angle. _Is expressed as β _FL , and the diffusion 1/10 value angle is expressed as γ _FL , the values of β _FL / α _FL , γ _FL / α _FL , and γ _FL / β _FL are reduced, and the light diffusing unit 40 It is preferable that the degree of light diffusion in the above is greater than the degree of light diffusion in the Fresnel lens sheet. At this time, it is preferable that the degree of light diffusion in the light diffusing unit 40 and the Fresnel lens sheet is α ₂₅ / α _FL > 2, β ₂₅ / β _FL > 3, and γ ₂₅ / γ _FL > 4. By constructing a transmissive screen by combining such a lens unit 50 and a Fresnel lens sheet, it becomes easy to prevent scintillation (glare), moire, and the like. If the degree of light diffusion in the vertical direction of the Fresnel lens sheet is made larger than the degree of light diffusion in the horizontal direction of the Fresnel lens sheet, it is more preferable from the viewpoint of preventing scintillation (glare), moire, and the like. Become.

Hereinafter, the above formulas (I) and (II), which are characteristic features of the present invention, will be described in detail. In the light diffusing member of the present invention, the refractive index of the convex cylindrical lens 5 is n _c , the ratio of the width of the stripe-shaped light shielding portion 15 to the pitch P _c of the convex cylindrical lens 5 is A, and the thickness of the translucent resin layer 30 Is set so that the thickness T of the translucent resin layer 30 satisfies the following formula (I).

In the light diffusing member of the present invention, the thickness T of the translucent resin layer 30 depends on the above formula (I) in relation to the pitch P _c of the convex cylindrical lens 5 and the ratio A of the width of the light shielding portion 15 to the pitch P _c . Therefore, the light backscattered by the light diffusing unit 40 is totally reflected at the interface between the refractive surface of the adjacent convex cylindrical lens 5 and the medium (air) outside thereof and travels toward the observation side (the other surface side). Even so, the light is blocked by the light blocking portion 15 formed at a ratio A to the pitch _Pc of the convex cylindrical lens 5. As a result, the light generated based on the back scatter is effectively blocked by the light shielding unit 15, so that the light emitted to the observation side as retroreflected light can be reduced, and the decrease in contrast and the decrease in resolution are suppressed. be able to. The reason for this will be described in detail with reference to FIGS.

  2 and 3 are schematic views for explaining the reason why generation of retroreflected light is suppressed in the light diffusing member 50 shown in FIG. FIG. 2 shows an example of a light diffusing member in which the light diffusing portion 40 is directly joined to the back surface 10a of the lenticular lens portion 10 via the light shielding pattern 20 without providing the translucent resin layer 30. These are the forms which show an example of the light-diffusion member which concerns on this invention which provided the translucent resin layer 30. FIG. Further, in FIGS. 2 and 3, in order to distinguish the convex cylindrical lenses from each other, reference numerals 5a, 5b, 5c, 5d, or 5e are given to the individual convex cylindrical lenses. Further, in order to make the optical path easy to understand, hatching is omitted.

  First, the reason why the light back-scattered on the optical axis OA of the convex cylindrical lens 5a is suppressed from being retroreflected light will be described.

  As already described, most of the light that can be retroreflected out of the light collected by a certain convex cylindrical lens 5 a is diffused in the light diffusing section 40 due to the configuration of the light diffusing member 50. After backscattering with the material 34, the light propagates to the convex cylindrical lenses 5 b and 5 c adjacent to the convex cylindrical lens 5 a, and is totally reflected at the interface between the refractive surface of the adjacent convex cylindrical lenses 5 b and 5 c and the medium (for example, air) outside thereof. reflect. The retroreflected light is light emitted from a transmission region (region between light shielding portions) on the optical axis of the adjacent convex cylindrical lenses 5b and 5c or further adjacent convex cylindrical lenses 5d and 5e among the totally reflected light. is there.

Now, assuming that the light diffusing portion 40 is directly bonded to the back surface 10a of the lenticular lens portion 10 via the light shielding pattern 20 without providing the light transmissive resin layer 30 as in the light diffusing member 50a shown in FIG. Lights L ₁ , L ₂ , L ₃ , and L ₄ (hereinafter referred to as L _{1 to} L ₄ ) out of the light that is reflected back and scattered by the light diffusing material 34 at the point O ₁ on the optical axis OA are shielded. The light propagates into the lenticular lens unit 10 without being blocked by the pattern 20. The propagated lights L _{1 to} L ₄ are repeatedly totally reflected at the interface between the refractive surface of the convex cylindrical lens 5 b or 5 c adjacent to the convex cylindrical lens 5 a and the medium outside the light L _{1 to} L ₄ , and a part of the reflected light 20 The light is emitted from the transmission region (region between the light shielding portions) on the optical axis of the convex cylindrical lens 5b or 5c without being blocked by the light, and becomes retroreflected light RL ₃ and RL ₄ .

On the other hand, in FIG. 2, among the light backscatter at the point O _1, light incident on the refracting surface of the convex cylindrical lenses 5a, in order to emit from it refracting surface on the light source side, not on the retroreflected light.

Further, as in the case of the light diffusing member 50 shown in FIG. 3, when the translucent resin layer 30 having a predetermined thickness T is provided and the light diffusing portion 40 is joined so as to cover the translucent resin layer 30. In FIG. 2, backscattering occurs at a point O ₂ farther from the lenticular lens unit 10 than the point O ₁ shown in FIG. Of the backscattered light, the light L ₅ and L ₆ that propagates to the lenticular lens unit 10 without being blocked by the light blocking pattern 20 are all incident on the convex cylindrical lens 5a. Since the lights L ₅ and L ₆ are emitted without being totally reflected by the refractive surface of the convex cylindrical lens 5a, they are not retroreflected light. Further, the other light L ₇ and L ₈ are blocked by the light blocking pattern 20 and do not propagate to the adjacent convex cylindrical lenses 5b and 5c.

Therefore, the value of the thickness T of the translucent resin layer 30, by greater than the value of the distance between the rear surface 10a of the O ₁ and the lenticular lens portion 10 points shown in FIG. 2, and more preferably the view 3, even if the light backscattered by the light diffusing unit 40 propagates to the lenticular lens unit 10, the light is suppressed from being retroreflected as much as possible. can do. Distance between the point O ₁ and the back 10a, and the distance between the point O ₂ and the back 10a can be determined, for example, as follows.

FIG. 4 is a schematic diagram for explaining how to obtain the distances between the points O ₁ and O ₂ shown in FIGS. 2 and 3 and the back surface 10 a of the lenticular lens unit 10. Also in the figure, hatching is omitted as in FIG.

The distance between the point O ₁ and the back surface 10 a and the distance between the point O ₂ and the back surface 10 a are such that the refractive index nc of the material of the convex cylindrical lenses 5 a to 5 _c is the translucent resin layer 30. Write when larger refractive index n _t is a refractive index n _t is longer than when a refractive index greater than n _c. However, as already described, the difference between the refractive index of the material of the convex cylindrical lenses 5a to 5c and the refractive index of the translucent resin layer 30 is preferably within 0.05, and the difference in refractive index between the two is when satisfying this requirement, the distance between the point O ₁ and the back 10a, and the maximum value of each distance between the point O ₂ and the back 10a is the distance when the refractive index n _c and a refractive index n _t are equal to each other Can be approximated. Hereinafter, as equal to each other and the refractive index n _c the refractive index n _t, and, in any of the convex cylindrical lens bodies 5a to 5c, the optical axes OA parallel to the convex cylindrical lenses 5a, 5b, or 5c of The condensing point O of the light L incident on the end in the width direction will be described as being on the back surface 10a of the lenticular lens unit 10. In addition, when the lenticular lens part 10 is comprised by the several layer from which refractive index differs, the refractive index of the surface (back surface 10a) in which the convex cylindrical lenses 5a-5c are not formed is made into a reference | standard.

When the refractive index n _t of the refractive index n _c and the transparent resin layer 30 of the convex cylindrical lenses 5a~5c materials are equal to each other, the light L ₁ shown in FIG. 2, O ₁ and point a point shown in FIG. 4 becomes a line connecting the Q _1, is on the line segment would be located point R shown in FIG. Further, the light L ₅ shown in FIG. 3 becomes the line segment connecting the O ₂ and the point Q ₂ points shown in FIG. 4, the point R to the line segment will be located. Here, the point Q ₁ is the width direction left in the refractive surface of the convex cylindrical lenses 5b (meaning left under the state shown in FIG. Hereinafter the same.) Indicates the point Q ₂ are convex The left end in the width direction on the refracting surface of the cylindrical lens 5a is shown. A point R indicates a cross-sectional intersection point between the side surface on the convex cylindrical lens 5a side of the light shielding portion 15 that overlaps both the convex cylindrical lenses 5a and 5b in plan view and the back surface 10a of the lenticular lens portion 10. Yes.

At this time, when an intersection between a perpendicular line drawn from the point Q ₂ on the optical axis OA of the convex cylindrical lens 5a and the optical axis OA and "S", the point Q ₁ is positioned on an extended line of the line segment SQ ₂ Therefore, the triangle O ₁ OR and the triangle O ₁ SQ ₁ are similar to each other. The triangle O ₂ OR and the triangle O ₂ SQ ₂ are similar to each other.

Here, as described above, the light shielding pattern 20 defines a band-shaped light transmission portion having the optical axis OA as an axis of symmetry around the optical axis OA of each of the convex cylindrical lenses 5a to 5c. When the interval between the light shielding portions 15 that match each other is “D”, the distance between the point O and the point R is represented by D / 2. The width of each of the convex cylindrical lenses 5a~5c is equal to the pitch _{P c} of the convex cylindrical lenses adjacent, distance between the point _{Q 1,} the point S is expressed by _{(P c + P c / 2} ), distance between the point _{Q 2} and the point S is expressed by _P c / 2.

When the triangle O ₁ OR and the triangle O ₁ SQ ₁ are similar to each other, the distance between the point O and the point O ₁ is “T ₁ ”, and the point Q ₁ and the point Q ₂ when the back surface 10a is used as the reference plane, respectively. When the height of “t” is “t”, the following equation (i) is established.

Assuming that the width of each light shielding portion 15 is “W”, the pitch P _c is expressed by the following equation (ii). Therefore, the ratio of the above-described ratio A, that is, the pitch P _c of the convex cylindrical lens, The ratio of the width can be expressed by the following formula (iii). Then, by transforming the formula (iii), the following formula (iv) is obtained.

  Substituting the above equation (iv) into equation (ii) yields the following equation (v), and transforming this equation (v) yields the following equation (vi).

  Substituting equation (vi) into equation (i) described above yields the following equation (vii), and transforming this equation (vii) yields the following equation (viii).

When the triangle O ₂ OR and the triangle O ₂ SQ ₂ are similar to each other, when the distance between the point O and the point O ₂ is “T ₂ ”, the following expression (ix) is established.

  Then, by substituting the above formula (vi) into this formula (ix), the following formula (x) is obtained.

Here, if the incident angle is phi ₁ when the light L incident from the outside of the refracting surface of the convex cylindrical lens 5a of the optical axis OA and parallel to the convex cylindrical lens 5a to the point Q ₂ is incident on the rear surface 10a, the point The height t of each of Q ₁ and point Q ₂ is expressed by the following equation (xi).

Since the refractive index nc of the material of the convex cylindrical lenses 5 a to 5 _c and the refractive index n _t of the translucent resin layer 30 are equal to each other as described above, the light L is transmitted between the translucent resin layer 30 and the light diffusion portion 40. If the incident angle when entering the interface is “φ ₂ ”, the height t takes the minimum value when the incident angle φ ₂ is a critical angle. Further, when the light L passes through the translucent resin layer 30 and the light diffusing portion 40 and is emitted from the light diffusing member 50, the light L enters the interface between the light diffusing portion 40 and the medium (air) outside thereof. the angle φ ₃ is equal to or less than the critical angle. Incidentally, one-dot chain line CL ₁ in FIG. 4 shows the normal at the interface between the light-transmitting resin layer 30 and the light diffusion unit 40, a chain line CL ₂ is the outside the light diffusing portion 40 medium (air ) And the normal line at the interface.

When the incidence angle phi ₃ described above critical angle, the following formula (xii) holds. Here, the symbol “n _d ” in the formula (xii) represents the refractive index of the matrix material 32 constituting the light diffusion portion 40.

Since each other equal to the refractive index n _c, as described above and the refractive index n _t, equal to each other and the incident angle phi ₁ and the incident angle phi _2. Therefore, the incident angle φ ₁ can be expressed by the following equation (xiii) from the above equation (xii). Further, when the formula (xiii) is substituted into the formula (xi), the following formula (ivx) is obtained.

  When the above formula (ivx) is substituted into the above formula (viii), the following formula (vx) is obtained. When the above formula (x) is substituted, the following formula (vix) is obtained.

Thus, greater than the value of the distance T ₁ a value of the thickness T of the light-transmitting resin layer 30 is represented by the above formula (vx), in other words, the thickness T of the light-transmitting resin layer is above If the formula (I) is satisfied, the light backscattered by the light diffusing unit 40 is prevented from propagating to the lenticular lens unit 10 and becoming retroreflected light. Then, is greater than the value of the distance T ₂ value of the thickness T of the light-transmitting resin layer 30 is represented by the above formula (xvi), in other words, the thickness T of the light-transmitting resin layer is above If the above formula (II) is satisfied, it is further suppressed that the light back-scattered by the light diffusing unit 40 propagates to the lenticular lens unit 10 and becomes retroreflected light.

  In the light diffusing member of the present invention, since the thickness T of the translucent resin layer satisfies the above formula (I), the translucent resin layer in the light diffusing member 50 shown in FIGS. A thickness T of 30 also satisfies the aforementioned formula (I). Therefore, according to the light diffusing member 50, it is suppressed that the light back-scattered by the light diffusing unit 40 propagates to the lenticular lens unit 10 and becomes retroreflected light. Then, by selecting the thickness T so that the thickness T of the translucent resin layer 30 satisfies the above-mentioned formula (II), the light back-scattered by the light diffusion unit 40 is propagated to the lenticular lens unit 10. Thus, it is possible to further suppress retroreflected light.

  Note that the backscatter in the light diffusing unit 40 does not occur only on the optical axis OA of each convex cylindrical lens, but also occurs at a location off the optical axis OA. The luminance is the highest and the amount of emitted light decreases as the viewing angle increases. Many viewers view images from the front. In consideration of these matters, in order to prevent a decrease in resolution and a decrease in contrast in the rear projection display caused by the light that has been backscattered by the light diffusing unit 40 being retroreflected light, first the front of the screen is used. Therefore, it is desirable to take into consideration the prevention of resolution and contrast deterioration. Therefore, it is preferable to suppress the light that has been backscattered on the optical axis OA from being retroreflected as described above.

(Light diffusing member: second embodiment)
The shape of the back surface of the lenticular lens portion in the light diffusing member of the present invention is not limited to a flat surface, and the portion where the light shielding portion is to be formed may be shaped like a trapezoid.

  FIG. 5 is a cross-sectional view schematically showing an example of the light diffusing member of the present invention in which the back surface of the lenticular lens portion has the above shape. The light diffusing member 60 shown in the figure includes a lenticular lens portion 10A in which a large number of trapezoidal portions 10p are formed in a stripe shape on the back surface 10a side, and the trapezoidal portions on the upper surface and side surfaces of the individual trapezoidal portions 10p. The light diffusing member 30 has the same structure as the light diffusing member 30 shown in FIG. 1 except that the light shielding pattern 20a is constituted by the light shielding portion 15a formed so as to cover 10p. Of the constituent members shown in FIG. 5, those common to the constituent members shown in FIG. 1 are given the same reference numerals as those used in FIG.

  In the lenticular lens portion 10A, for example, a mold roll for forming the convex cylindrical lens 5 and a mold roll for forming the base portion 10p are arranged so that their molding surfaces face each other. It can be obtained by forming a transparent resin formed into a shape or a sheet into a predetermined shape with these rolls before the transparent resin is cured. Further, each light shielding portion 15a can be formed by, for example, a printing method. By appropriately selecting the printing conditions, it is possible to form the light-shielding portion 15a having a desired shape in one step.

  Also in the light diffusing member 60 having the above structure, by selecting the thickness T of the translucent resin layer 30 so that the thickness T satisfies the above formula (I), the light diffusing unit 40 can perform backscattering. Propagated light is prevented from propagating to the lenticular lens portion 10A and becoming retroreflected light. Then, by selecting the thickness T of the translucent resin layer 30 so that the thickness T satisfies the above-described formula (II), the light back-scattered by the light diffusion unit 40 propagates to the lenticular lens unit 10A. Thus, it is possible to further suppress retroreflected light.

(Light diffusing member: third embodiment)
The structure of the lenticular lens portion in the light diffusing member of the present invention is not limited to a single layer structure, and may be a laminated structure.

  FIG. 6 is a cross-sectional view schematically showing an example of the light diffusing member of the present invention provided with a lenticular lens portion having a laminated structure. In the light diffusing member 70 shown in the figure, a lenticular lens portion 10B having a laminated structure is formed by providing a convex cylindrical lens group 5G composed of a large number of convex cylindrical lenses 5 on one surface of the base film 1. The translucent resin layer 30 is bonded to the other surface of the base film 1 via the light shielding pattern 20. 6 that are the same as those shown in FIG. 1 are given the same reference numerals as those used in FIG. 1 and description thereof is omitted.

  In the case of forming a lenticular lens portion having a laminated structure like the illustrated lenticular lens portion 10B, it is preferable to suppress the physical interface between adjacent layers in the thickness direction from becoming an optical interface. The refractive index difference between these layers is preferably about 0.05 or less. The lenticular lens portion having a laminated structure can be formed of a transparent resin having a refractive index of about 1.45 to 1.60, for example, similarly to the lenticular lens portion having a single layer structure. For example, the convex cylindrical lens group 5G can be formed of an ultraviolet curable resin such as urethane, epoxy, or polyester, and the base film 1 can be a transparent film made of polyester, polycarbonate, acrylic, or the like. . If necessary, a small amount of a light diffusing material can be dispersed in the transparent resin.

  Also in the light diffusing member 70 having the above-described structure, the light diffusing unit 40 can perform backscattering by selecting the thickness T of the translucent resin layer 30 so that the thickness T satisfies the above-described formula (I). Propagated light is prevented from propagating to the lenticular lens portion 10B and becoming retroreflected light. Then, by selecting the thickness T of the translucent resin layer 30 so that the thickness T satisfies the above-described formula (II), the light back-scattered by the light diffusing unit 40 propagates to the lenticular lens unit 10B. Thus, it is possible to further suppress retroreflected light.

(Light diffusion member: 4th form)
In the light diffusing member of the present invention, a layer having a desired function such as an antistatic layer, an antireflection layer, an antiglare layer or the like (hereinafter referred to as “functional layer”) as the outermost component on the light diffusing portion 40 side. ).

  FIG. 7 is a cross-sectional view schematically showing an example of the light diffusing member of the present invention having the above structure. The light diffusing member 80 shown in the figure has the same structure as the light diffusing member 50 shown in FIG. 1 except that a functional layer 75 is provided on the outer surface of the light diffusing portion 40. Among the structural members shown in FIG. 7, those common to the structural members shown in FIG. 1 are assigned the same reference numerals as those used in FIG.

  The illustrated functional layer 75 is directly formed on the light diffusing unit 40, but the functional layer 75 may be affixed on the light diffusing unit 40 using a transparent bonding agent. What function layer is provided as the functional layer 75 is appropriately selected according to the application, grade, and the like of the light diffusion member 80.

  By providing an antistatic layer as the functional layer 75, it is possible to suppress the adhesion of dust to the surface of the light diffusing member 80 (the surface of the functional layer 75). As a result, the light diffusing member 80 is used. In addition, the transmissive screen can easily maintain the optical characteristics even when the frequency of cleaning is low. Further, by providing an antireflection layer as the functional layer 75, reflection of external light on the surface of the light diffusing member 80 (surface of the functional layer 75) can be suppressed. As a result, the diffused light by the light diffusing member 80 is reduced. It is possible to suppress the reflected light from being superimposed. Further, by providing an antiglare layer as the functional layer 75, it is possible to suppress glare when the surface of the light diffusion member 80 (the surface of the functional layer 75) is visually recognized. As a result, the light diffusion member 80 is used. It is also possible to suppress glare on the transmissive screen constructed as described above.

  Also in the light diffusing member 80 having the above-described structure, the light diffusing unit 40 can perform backscattering by selecting the thickness T of the translucent resin layer 30 so that the thickness T satisfies the above-described formula (I). The transmitted light is prevented from propagating to the lenticular lens unit 10 and becoming retroreflected light. Then, by selecting the thickness T of the translucent resin layer 30 so that the thickness T satisfies the above formula (II), the light back-scattered by the light diffusing unit 40 propagates to the lenticular lens unit 10. Thus, it is possible to further suppress retroreflected light.

(Transparent screen)
The transmission screen of the present invention includes the above-described light diffusing member of the present invention and a Fresnel lens sheet disposed outside the refractive surface of the convex cylindrical lens in the light diffusing member.

  FIG. 8 is a perspective view schematically showing an example of the transmission screen of the present invention. The illustrated transmission screen 120 includes the light diffusing member 50 illustrated in FIG. 1 and the Fresnel lens sheet 110 disposed outside the refractive surface of the convex cylindrical lens 5 in the light diffusing member 50. Since the light diffusion member 50 has already been described, the description thereof is omitted here. 8 that have already been described with reference to FIG. 1 are denoted by the same reference numerals as those used in FIG. 1 and description thereof is omitted.

  The Fresnel lens sheet 110 has a large number of prisms 105 on one surface in the thickness direction and is formed in a concentric arc shape centering on a virtual point Ov outside the surface, and the other surface in the thickness direction. Is formed into a flat surface. The imaginary point Ov means a vertical axis Ax of the Fresnel lens sheet 110 (an axis extending in the height direction of the Fresnel lens sheet 110 in the illustrated state) when the Fresnel lens sheet 110 is viewed from the front. The Fresnel lens sheet 110 is symmetrical with respect to the vertical axis Ax.

  In the Fresnel lens sheet 110, the pitch between the adjacent prisms 105 (meaning the interval between the apexes) is constant. This pitch is preferably about 1.0 mm or less, and more preferably about 0.1 mm or less so that each prism 105 is not visually recognized when a transmissive projection screen is formed using the Fresnel lens sheet 110. preferable. The shape of each prism 105 is such that visible light incident in the state of diverging light from behind and obliquely below one of the surfaces as viewed from the light diffusing member 50 side is converted into light that is parallel or substantially parallel to the thickness direction of the Fresnel lens sheet 110. It is selected so that it can be converted.

  The Fresnel lens sheet 110 and the light diffusing member 50 are supported and fixed at predetermined positions of the rear transmissive display in a state where the Fresnel lens sheet 110 is on the inner side and the light diffusing member 50 is separated on the outer side. Thus, the transmission screen 120 is configured.

  FIG. 9 is a partial cross-sectional view schematically showing an example of a rear projection display using the transmissive screen 120. In the rear projection display 130 shown in the figure, a projector 124 is disposed at the bottom of a thin casing 122, close to the inner surface of the rear wall of the casing 122, and parallel to the vertical direction on the screen surface (screen). A mirror 126 is arranged. Then, the transmission screen 120 shown in FIG. 8 is provided so as to close the window provided on the front wall of the housing 122. In this transmissive screen 120, the direction of the vertical axis Ax (see FIG. 8) of the Fresnel lens sheet 110 and the longitudinal direction of each convex cylindrical lens 5 in the light diffusing member 50 are respectively perpendicular to the screen surface (screen). In this direction, the light diffusing member 50 is supported on the outside by a support member (not shown).

  In the rear projection display 130 having such a structure, a projection optical system is configured by the projector 124 and the mirror 126, and the image light ML emitted from the projector 124 is transmitted to the transmission screen 120 side by the mirror 126. The light is reflected and enters the transmission screen 120 in a divergent light state. The image light ML incident on the transmissive screen 120 is converted into image light parallel or substantially parallel to the thickness direction of the Fresnel lens sheet 110 by the Fresnel lens sheet 110 (see FIG. 8), and further, the light diffusion member 50. The light is diffused by (see FIG. 8) and emitted from the rear projection display 130.

  As already described, the light diffusing member 50 is easy to improve the viewing angle characteristics and the resolution of the rear projection display, respectively. Therefore, the rear projection display 130 provided with the light diffusing member 50 includes: This is a rear projection display that can easily obtain a display with excellent viewing angle characteristics and resolution.

  The transmission screen of the present invention is not limited to the transmission screen 120 described above. As long as the light diffusing member of the present invention described above is used, various modifications, modifications, combinations, and the like can be made in addition to the transmission screen 120 described above. For example, the light diffusing member shown in FIG. 5, FIG. 6, or FIG. 7 may be used in place of the light diffusing member 50. In addition, as the Fresnel lens sheet, it is possible to use a plurality of annularly shaped prisms that are concentrically arranged around a virtual point in one surface in the thickness direction, and the planar shape is a band shape. Alternatively, a large number of linear prisms (linear Fresnel lens sheet) formed in parallel to each other may be used. The individual prisms constituting the Fresnel lens sheet may convert the direction distribution of the image light using total reflection, or convert the direction distribution of the image light using refraction. Also good.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples.

Example 1
First, a 25 μm thick polyester film (refractive index; 1.59) is used as a base film, and a urethane-based ultraviolet curable resin composition having a refractive index of 1.5 is applied to one surface in the thickness direction of the polyester film. A lenticular lens portion was formed by using it to obtain a lenticular lens. In the above lenticular lens portion, a large number of convex cylindrical lenses are formed at a pitch of 50.0 μm, and the refracting surfaces of the individual convex cylindrical lenses have a lateral radius (radius in the arrangement direction of the large number of convex cylindrical lenses). The aspherical surface is 3 μm and has a longitudinal radius (radius in the thickness direction of the convex cylindrical lens) of 36 μm. The maximum thickness of the lenticular lens portion (thickness from the top of the lenticular lens portion to the emission plane) is 57.5 μm. When the lenticular lens portion is composed of a plurality of layers having different refractive indexes as in Example 1, the refractive index of the surface (back surface 10a) on which the convex cylindrical lens is not formed is used as a reference. And

  Next, a negative photosensitive resin having a refractive index of 1.55 is applied to the other surface of the lenticular lens, that is, the exit surface side that is the other surface in the thickness direction of the polyester film by a roll coating method. A photosensitive resin layer (light transmission layer) having a thickness of 10 μm is formed, and the photosensitive resin layer is selectively exposed by irradiating ultraviolet rays substantially vertically from the refractive surface side of each convex cylindrical lens, and then developed. Thus, a light transmission layer composed of a photosensitive resin layer that was not dissolved during development was obtained. Thereafter, a black ink was filled in the concave portion formed by dissolving the photosensitive resin layer by the above-described development by a wiping method to form a light shielding pattern.

This light shielding pattern is composed of a large number of light shielding portions arranged at a pitch of 50.0 μm, and each light shielding portion has a strip shape. Each light shielding part has a height (thickness) of 10 μm and a width of 30 μm. The width of the light shielding portion is substantially constant in the thickness direction, in other words, substantially constant from the surface on the lenticular lens portion side to the surface opposite to the lenticular lens portion. Further, the ratio (BS ratio) of the total area of each light shielding part in plan view to the area of the other surface of the lenticular lens is 60%, and the ratio A of the width of the striped light shielding part to the pitch P _c is also 60. %.

  Thereafter, the thickness of the other surface of the lenticular lens and the light shielding pattern is 15 μm (meaning the thickness of the other surface of the lenticular lens that is exposed without being covered by the light shielding pattern). The acrylic pressure-sensitive adhesive layer was formed, and a light diffusion plate having a thickness of 2 mm was joined to the lenticular lens by this acrylic pressure-sensitive adhesive layer. The light diffusing plate is obtained by dispersing an acrylic styrene-based diffusing agent in an impact-resistant acrylic resin having a refractive index of 1.5, and its diffusion half-value angle is 6 °.

  By joining this light diffusing plate to a lenticular lens, the intended light diffusing member was obtained. By combining the light diffusing member and the Fresnel lens, it is possible to obtain a transmission screen having good viewing angle characteristics, high image contrast, and sharp image quality.

(Example 2)
First, a first mold roll having a large number of recesses for forming a convex cylindrical lens and a second mold roll for forming a platform (see FIG. 5) are prepared. These mold rolls were arranged close to the extruder so that the center of the concave part and the center of the convex part of the second mold roll face each other under a predetermined interval during molding.

  Next, a sheet of impact-resistant acrylic resin having a refractive index of 1.5 is formed by the above-described extruder, and is formed by the first mold roll and the second mold roll before the sheet is cooled and cured. Thus, a lenticular lens having the same shape as the lenticular lens shown in FIG. 5 was obtained.

  In this lenticular lens, a large number of convex cylindrical lenses are formed at a pitch of 300.0 μm, and the refracting surface of each convex cylindrical lens has a lateral radius (radius in the arrangement direction of a large number of convex cylindrical lenses) of 152.0 μm, The aspherical surface has a longitudinal radius (radius in the thickness direction of the convex cylindrical lens) of 216.0 μm. The maximum thickness of the lenticular lens (thickness from the top of the lenticular lens portion to the emission plane) is 345 μm, and on the other surface, a trapezoidal portion having a width of 180 μm and a height of 50 μm in a planar shape. Many are formed at a pitch of 300.0 μm.

Next, black ink was applied on each of the above-mentioned table-like portions by a gravure offset printing method. At this time, the printing pressure, the amount of ink, and the hardness of the printing rubber roll were adjusted so that the ink also flowed to the side surface of each table-like portion. Thereby, the light-shielding part which covers the said base-shaped part one by one in one base-shaped part was formed, and the light-shielding pattern was obtained. The thickness of the light-shielding portion on the upper surface of each trapezoidal portion is 3 μm, and the width of each light-shielding portion is substantially constant in the height direction (thickness direction of the trapezoidal portion). Further, the ratio (BS ratio) of the total area of each light shielding part in plan view to the area of the other surface of the lenticular lens is 60%, and the ratio A of the width of the striped light shielding part to the pitch P _c is also 60. %.

  Thereafter, the light diffusing plate was joined to the lenticular lens under the same conditions as in Example 1 to obtain a target light diffusing member. That is, an epoxy acrylate UV adhesive layer (refractive index: 1.49) having a thickness of 80 μm is formed so as to cover the other surface of the lenticular lens and the light shielding pattern, and light diffusion having a thickness of 2 mm is performed by this adhesive layer. The plate was bonded to a lenticular lens. The light diffusing plate is obtained by dispersing an acrylic styrene-based diffusing agent in an impact-resistant acrylic resin having a refractive index of 1.5, and its diffusion half-value angle is 6 °. By combining the light diffusing member and the Fresnel lens, it is possible to obtain a sharp transmissive screen with good viewing angle characteristics, high image contrast and resolution.

  Further, in this light diffusing member, even if the relative position between the optical axis of the convex cylindrical lens and the center of the light shielding portion in plan view is shifted within a range of ± 15 μm in the arrangement direction of each cylindrical lens, the above relative Thus, a transmissive screen using the same transmissive screen as that having the same viewing angle characteristics and image quality as that of a screen having no misalignment can be obtained.

It is sectional drawing which shows schematically the basic structure of the light-diffusion member of this invention. It is the schematic for demonstrating the reason the generation | occurrence | production of retroreflection light is suppressed in the light-diffusion member shown in FIG. It is another schematic diagram for demonstrating the reason that generation | occurrence | production of retroreflection light is suppressed in the light-diffusion member shown in FIG. Is a schematic diagram for explaining how to determine the distance between the rear surface of the O _1, O ₂ and the lenticular lens portion that shown in FIGS. It is sectional drawing which shows roughly an example of the light-diffusion member of this invention in which the location which is going to form a light-shielding part in the back surface of a lenticular lens part becomes the shape which protruded in the trapezoid shape. It is sectional drawing which shows roughly an example of the light-diffusion member of this invention provided with the lenticular lens part of laminated structure. Section which shows roughly an example of the light-diffusion member of this invention which has the structure in which the layer which has desired functions, such as an antistatic layer, an antireflection layer, an anti-glare layer, was provided as the outermost component by the side of a light-diffusion part FIG. It is a perspective view which shows roughly an example of the transmission type screen of this invention. FIG. 9 is a partial cross-sectional view schematically showing an example of a rear projection type display using the transmissive screen shown in FIG. 8.

Explanation of symbols

5, 5a, 5b, 5c, 5d, 5e Convex Cylindrical Lens 5G Convex Cylindrical Lens Group 10, 10A, 10B Lenticular Lens Part 10a The other side (back side) of the lenticular lens part in the thickness direction
10p base part 15, 15a light-shielding part 20, 20a light-shielding pattern 30 translucent resin layer 32 translucent resin (matrix material)
34 Light diffusing material 40 Light diffusing portion 50, 50a, 60, 70 80 Light diffusing member 75 The outermost component on the light diffusing portion side in the light diffusing member (functional layer; antistatic layer, antireflection layer, antiglare layer, etc.)
105 prism 110 pitch T of the Fresnel lens sheet 120 transmission screen 130 rear projection display 122 housing 124 pitch P _S shielding portion of the convex cylindrical lenses adjacent the optical axis P _c of the projector 126 mirrors ML image light OA convex cylindrical lens Thickness of translucent resin layer H Height of light shielding part W Width of light shielding part

Claims (7)

A sheet-like lenticular lens portion in which a number of convex cylindrical lenses are formed in parallel with each other at a constant pitch _Pc on one surface side in the thickness direction, and a stripe on the other surface in the thickness direction of the lenticular lens portion A light-shielding pattern comprising a plurality of light-shielding portions arranged in a shape, a light-transmitting resin layer formed to cover the other surface and the light-shielding pattern, and a light-transmitting resin in which a light diffusing material is dispersed. A light diffusing member having a light diffusing portion bonded to the translucent resin layer,
When the refractive index of the convex cylindrical lens is n _c , the ratio of the width of the stripe-shaped light shielding portion to the pitch P _c is A, and the thickness of the translucent resin layer is T, the thickness T is A light diffusing member satisfying the following formula (I):

The light diffusing member according to claim 1, wherein the thickness T satisfies the following formula (II).

  The light diffusing member according to claim 1, wherein the translucent resin layer is a transparent resin layer not including a light diffusing material.   The light diffusion member according to any one of claims 1 to 3, further comprising an antistatic layer as an outermost component on the light diffusion portion side.   The light diffusion member according to any one of claims 1 to 3, further comprising an antireflection layer as an outermost component on the light diffusion portion side.   The light diffusing member according to claim 1, further comprising an antiglare layer as an outermost component on the light diffusing portion side. A transmissive screen comprising: the light diffusing member according to any one of claims 1 to 6; and a Fresnel lens sheet disposed outside the refractive surface of the convex cylindrical lens in the light diffusing member. .

Images