JPH116903A - Lenticular lens sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the color shift of a lenticular lens sheet and to increase the transmissivity of all light rays. SOLUTION: Relating to a both-side lenticular lens sheet 10A having an entrance lenticular lens 11 on the entrance plane of a light ray and an exit lenticular lens 12 on the exit plane and forming the top part of the exit lenticular lens 12 on almost the converging position of the entrance lenticular lens 11, when representing a distance between lenses in the middle part of sheet by to and a distance between lenses at the end part of the effective screen range of a back-face projection screen constituted by using this lenticular lens sheet by t1 , 0.98<=t1 /t0 <=1.10 is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lenticular lens sheet used for a rear projection screen.

[0002]

2. Description of the Related Art Conventionally, as a method for displaying a large-screen image, there has been known a method of enlarging and projecting an optical image from a CRT or a liquid crystal panel onto a rear projection screen by a projection lens. FIG. 4 is a schematic configuration diagram of a general rear projection television for forming an image by this method, FIG. 5 is an explanatory view of light rays, and FIG. 6 is used in the rear projection television of FIG. FIG. 2 is a perspective view of a screen to be changed.

In the rear projection type television shown in FIG. 1, R (red), G
The optical images from the CRT 1 (green) and B (blue) are enlarged by the projection lens 2, reflected by the reflecting mirror 7, and formed on the rear projection screen 5 composed of the Fresnel lens 3 and the lenticular lens sheet 4. You. Here, the Fresnel lens 3 has a function of substantially directing the incident light in the direction in which the observer is located, and the lenticular lens sheet 4 directs the light emitted from the Fresnel lens 3 at a predetermined angle in the horizontal and vertical directions. In an appropriate distribution ratio to widen the viewing angle in a predetermined range.

However, in such a display device, the position of observing the screen 5 is changed in the horizontal direction due to the concentration angle ε of the projection light of each of the R, G, and B CRTs 1 so that the position on the screen is changed. The color of the image also changes (see FIG. 5). That is, in the normal arrangement of the CRT 1, the green is located at the center, and the red and blue are shifted left and right. Therefore, when the observation position is changed left and right, the color of red or blue becomes stronger. Such a phenomenon is called a color shift.

Therefore, in order to reduce the color shift,
Conventionally, as shown in FIG. 7, as a lenticular lens sheet, an incident-side lenticular lens 11 in which a plurality of cylindrical lenses are arranged in parallel on a light incident side, and an exit-side lenticular in which a plurality of cylindrical lenses are arranged in parallel on an exit side. It is known to use a double-sided lenticular lens sheet 10 in which a lens 12 is formed and a light-absorbing layer 13 is formed on a non-light-collecting portion of an incident-side lenticular lens 11 on the exit side.

On the other hand, at present, as a method of manufacturing a lenticular lens sheet, an extrusion molding method of a thermoplastic resin is used because of high productivity and the like. In this method, the temperature at the end of the die is adjusted to be 5 to 10 ° C. higher than that at the center so that smooth extrusion can be performed over the entire width of the die. This is to compensate for the pressure drop in the manifold at the end by lowering the viscosity.

[0007]

However, the thickness of the lenticular lens sheet is generally 0.5 mm to
Because it is as thin as 1.5 mm, in the conventional extrusion molding method, when sandwiching the molten resin between the shaping rolls,
The pressure in the width direction of the shaping roll becomes non-uniform, so that the shaping roll largely bends at the peripheral portion with respect to the center portion, so-called roll bending occurs. Therefore, even if the intention is to form a lenticular lens sheet having a uniform thickness in the width direction,
Actually, as shown in FIG. 8, the inter-lens distance t _{1 at} the peripheral portion of the double-sided lenticular lens sheet 10 (more specifically, at the end of the effective image area of the rear projection screen formed using the lenticular lens sheet) Actually, the inter-lens distance t ₁ ) is several percent or more smaller than the thickness t ₀ at the center. In order to unexpectedly reduce the distance between the lenses at the peripheral portion, as shown in FIG. 2, the light beam L incident on the emission side lenticular lens 12 at the peripheral portion of the double-sided lenticular lens sheet 10 is used.
Incident angle θ ₁ of the double-sided lenticular lens sheet 10
At the center of the light-emitting lenticular lens 12 becomes significantly larger than the incident angle θ ₀ of the light-emitting lenticular lens 12, causing a problem that the total light transmittance is reduced.

Further, when the incident angle θ ₀ is increased, the light absorbing layer 13 prevents the light beam L from being emitted from the light-emitting side lenticular lens 12 from being emitted. Plus red C
Since the difference between the incident angle θ _1R when the light ray from the RT enters the emission side lenticular lens 12 and the incident angle θ _1B when the light ray from the blue CRT enters the emission side lenticular lens 12 becomes large, The color shift was also getting bigger.

These problems caused by the decrease in the distance between the lenses are caused by the single-sided lenticular lens sheet 10x shown in FIG. 9 (that is, the incident side lenticular lens 11 is provided on the incident side of the light beam L, and this incident side lenticular lens 11 is provided). A lenticular lens sheet with a flat exit surface at the part where the light incident on the lenticular lens exits)
Does not occur. Single-sided lenticular lens sheet 10
At x, the sheet thickness of the lenticular lens sheet corresponding to the inter-lens distance of the double-sided lenticular lens 10 decreases from t ₀ to t ₁ , and the exit side of the light beam L is indicated by a broken line from the exit side S _{0 at the} initial position. Even if the position changes to the output side surface S ₁ , the output side surface S _{0 at the} initial sheet thickness is obtained.
The incident angle theta ₀ for the angle of incidence of the light beam L with respect to the exit side S ₁ after the sheet thickness becomes thinner than the theta _1, unchanged at θ ₀ = θ _1. Therefore, the transmittance of the light beam L at the emission side surfaces S ₀ and S ₁ does not change. In addition, a single-sided lenticular lens sheet inherently has a larger color shift than a double-sided lenticular lens sheet, but the degree of this color shift does not change as the sheet thickness decreases.

An object of the present invention is to solve the above-mentioned problems of the prior art. In a double-sided lenticular lens sheet capable of reducing a color shift with respect to a single-sided lenticular lens sheet, the present invention relates to a method for transmitting all rays of the sheet. It is an object of the present invention to improve efficiency of light and prevent light from being absorbed by a light absorbing layer formed on an emission side surface of a sheet, thereby improving light use efficiency and further reducing color shift.

[0011]

In order to achieve the above object, the present invention has an incident side lenticular lens on a light incident side surface, an output side lenticular lens on an exit side surface, and an incident side lenticular lens. In a double-sided lenticular lens sheet in which the top of the exit-side lenticular lens is formed at a substantially condensing position, this lenticular lens sheet is used for a distance between lenses, which is the distance between the top of the entrance-side lenticular lens and the top of the exit-side lenticular lens. When the distance between the lenses at the center of the effective screen range of the rear projection type screen used is t ₀ and the distance between the lenses at the end of the effective screen range is t ₁ , 0.98 ≦ t ₁ / t _0. <1.10. A lenticular lens sheet characterized by satisfying the following condition.

According to the present invention, since the actual lens-to-lens distance of the formed lenticular lens sheet is designed to be 0.98 or more at the end of the effective screen area of the screen as compared with the center, At the end of the lenticular lens sheet, the incident angle θ ₁ when the light incident on the incident side lenticular lens is incident on the exit side lenticular lens does not become excessively large, and the total light transmittance is improved. Blurring can be prevented, and the color shift can be further reduced.

The upper limit of the inter-lens distance at the end of the screen effective screen range with respect to the inter-lens distance at the center is 1.
Since it is 10, the lenticular lens sheet has a sufficient horizontal diffusion property. Therefore, it is possible to prevent a cutoff phenomenon due to a decrease in horizontal diffusion.

Such an effect is not obtained only when the lenticular lens sheet of the present invention is used for a rear projection screen that displays a color optical image using three CRTs. The rear projection type screen using the lenticular lens sheet of the present invention has a CR
In addition to the use of T, even when an LCD or DMD is used as the light source, the total light transmittance can be improved, and the horizontal diffusivity can be increased to prevent the cutoff phenomenon.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view in the width direction of a lenticular lens sheet 10A according to one embodiment of the present invention. As shown in the figure, this lenticular lens sheet 10A
Is the incident side lenticular lens 1 on the incident side of the light beam L.
1 is a double-sided lenticular lens sheet having an exit side lenticular lens 12 also on the exit side of the light beam L, and a light absorbing layer 13 is provided on a non-condensing portion of the entrance side lenticular lens 11 on the exit side of the light beam L It is a thing.

The entrance lenticular lens 11 and the exit lenticular lens 12 each have a shape in which cylindrical lenses are arranged in parallel in the width direction of the sheet. The top of the exit-side lenticular lens 12 is formed at a substantially condensing position of the entrance-side lenticular lens 11.

Here, the incident side lenticular lens 11
Is monotonically reduced with an increase in the distance x in the width direction (ie, the direction orthogonal to the longitudinal direction of the cylindrical lens) from the center of the sheet, and the lenticular lens sheet 10A
The radius of curvature Ri ₁ of the cylindrical lens of the entrance-side lenticular lens 11 at the end of the effective screen range of the rear projection type screen constituted by using is approximately several percent smaller than the radius of curvature Ri ₀ at the center of the sheet. Has become.

The lenticular lens sheet 1
Within the effective screen range of the rear projection screen configured using 0A, the distance t (x) between the lenses at a distance x in the width direction from the center of the effective screen area and the lens distance t _{0 at the} center of the effective screen area. The ratio t (x) / t ₀ monotonically increases with an increase in x, and the distance between the lenses at the end of the effective screen range of the rear projection screen formed using the lenticular lens sheet 10A is reduced. when a t _1, is _{0.98 ≦ t 1 / t 0 ≦} 1.10 is satisfied. FIG. 1 shows the ratio t of the distance between the lenses.
Although the case where (x) / t ₀ monotonically increases is shown, this embodiment also includes a case where the ratio t (x) / t ₀ of the distances between lenses monotonically decreases.

The lenticular lens sheet 10A shown in FIG.
The state of transmission of the light ray L in each of the central portion and the peripheral portion of FIG. In the lenticular lens sheet 10A, the inter-lens distance t ₁ at the end of the effective screen range of the screen is 0.98 or more with respect to the inter-lens distance t ₀ at the center. at the exit side incident angle theta ₁ of the light beam L incident on the lenticular lens 12 is not be significantly greater with respect to the incident angle theta ₀ to the lenticular lens 12 at the central portion, the incidence angle theta ₀ at the center Be equivalent. Further, since the top of the emission-side lenticular lens 12 is formed at a substantially condensing position of the incidence-side lenticular lens 11, light is not shaken by the light absorption layer 13. Therefore, according to the lenticular lens sheet 10A, the total light transmittance can be improved and the color shift can be reduced.

The lenticular lens sheet 10
In A, the inter-lens distance t ₁ at the end of the effective screen range of the screen is 1.10 or less with respect to the inter-lens distance t _{0 at the} center of the effective screen range, so that horizontal diffusion is ensured. You. Therefore, the cut-off phenomenon does not become a problem.

The lenticular lens sheet 10A of FIG.
As a manufacturing method of, for example, a so-called pressing method of preparing two flat molds having a reverse shape of a molded product, sandwiching a heated resin between them, pressurizing and cooling, or a reverse mold of a molded product An extrusion molding method or the like in which molten resin is flowed from a die between a pair of shaping rolls having a shape, and pressed and cooled can be used.

Among them, the extrusion molding method is useful as a method for producing a lenticular lens sheet of the present invention because the lens depth, sheet thickness, and the like can be gradually changed in the width direction of the sheet.

Here, when a lenticular lens sheet is manufactured by a pressing method or an extrusion molding method according to a conventional example, the thickness of the peripheral portion of the obtained lenticular lens sheet is several percent thinner than that of the central portion. Therefore, during molding, the thickness is controlled so that the thickness of the peripheral portion is increased with respect to the central portion. More specifically, for example, in the case of molding by an extrusion molding method, the resin pool (so-called bank) between the shaping roll and the resin is increased at the peripheral portion with respect to the central portion of the lenticular lens sheet. In the case of molding by an extrusion molding method, at least one of a pair of shaping rolls may be a crowning roll. In this case, the crowning amount of the roll depends on the banks at the center and the periphery, but
When these are not changed, it is preferable that the thickness be 20 μm or more per 1 m.

FIG. 2 is a cross-sectional view in a width direction of a lenticular lens sheet 10B according to another embodiment of the present invention. As shown in the figure, this lenticular lens sheet 10B
, Like the lenticular lens sheet 10A of FIG. 1, a double-sided lenticular lens sheet having a light absorbing layer 13 on the exit surface of the light beam L, from the sheet central portion than the inter-lens distance t ₀ in the sheet central portion The inter-lens distance t (x) where the distance in the width direction is x monotonically increases, and the inter-lens distance t ₁ at the end of the effective screen range of the rear projection screen is _{0 with} respect to the inter-lens distance t _{0 at the} center of the sheet. .98
It is molded so as to be up to 1.10 times. However, in the lenticular lens sheet 10B, the radius of curvature Ri of the cylindrical lens constituting the entrance-side lenticular lens 11 is the same over the entire width of the sheet, and the exit-side lenticular lens 1
The radius of curvature Ro of the cylindrical lens constituting the second lens unit 2 is the same over the entire width of the sheet.

FIG. 2 shows an inter-lens distance t (x) at a distance x from the center of the effective screen range of the rear projection type screen constituted by using the lenticular lens sheet 10B, and an effective face. Although the case where the ratio t (x) / t ₀ to the lens distance t ₀ in the center of the range is monotonically increased is shown, the case where the ratio t (x) / t ₀ is monotonously decreased is also the same. This embodiment includes:

FIG. 2 shows the state of light transmission at the central portion and the peripheral portion of the lenticular lens sheet 10B. This lenticular lens sheet 1
1B, the lenticular lens sheet 10B is similar to the lenticular lens sheet 10A of FIG.
The incident angle θ ₁ of the light beam L incident on the emission side lenticular lens 12 in the peripheral portion of the lens does not become significantly larger than the incident angle θ ₀ on the lenticular lens 12 at the central portion, and the incident angle at the central portion It is equivalent to θ ₀ . Further, since the top portion of the emission-side lenticular lens 12 is formed at a substantially condensing position of the incidence-side lenticular lens 11, light is not shaken by the light absorbing layer 13. Therefore, it is possible to improve the total light transmittance and reduce the color shift as compared with the conventional lenticular lens sheet.

Here, the lenticular lens sheet 10B of FIG. 2 is replaced with the lenticular lens sheet 10A of FIG.
The lenticular lens sheet 10 of FIG.
B has a smaller angle of incidence θ ₁ of the light beam on the emission side lenticular lens 12 in the peripheral portion of the lenticular lens sheet than in the lenticular lens sheet 10A of FIG. For this reason, the lenticular lens sheet 10 of FIG.
The total light transmittance is higher than A. On the other hand, the horizontal diffusion angle is wider in the lenticular lens sheet 10A of FIG.

The lenticular lens sheet 10B shown in FIG.
As in the method of manufacturing the lenticular lens sheet 10A of FIG. 1, when forming using a pressing method, an extrusion molding method, or the like, the thickness of the peripheral portion is equal to or greater than that of the central portion. In addition, adjustment of the bank and the amount of crowning of the shaping roll are performed, but in the case of the extrusion molding method, the temperature of the die used for extrusion is made uniform between the central part and the peripheral part, or Is preferably 5 to 10 ° C. higher than the peripheral portion to increase the number of banks in the peripheral portion of the roll. By controlling the die temperature in this way,
Since the resin having a relatively low temperature is extruded from the periphery of the die, there may be a portion that cannot be used at the peripheral portion of the sheet. In this case, the portion may be cut off.

According to the present invention, in addition to the above-mentioned lenticular lens sheets 10A and 10B, the ratio t _{1/2 of the} distance t ₁ between lenses at the end of the effective screen range of the rear projection type screen and the distance t ₀ between lenses at the center of the sheet. t ₀ is 0.98 or more
Various modes can be adopted as long as the number is 10 or less.
For example, in the above-described example, the inter-lens distance t (x) at the distance x from the center of the sheet monotonically increases or decreases as x increases, but can be changed stepwise. Further, the distance between the lenses may be flat from the center of the sheet to the periphery of the sheet.

The lens shapes of the entrance lenticular lens 11 and the exit lenticular lens 12 are as follows.
In the lenticular lens sheets 10A and 10B described above, the outer shape of the cylindrical lens constituting each lenticular lens on the incident side or the output side forms an arc, and the shape is represented by a radius of curvature, but the outer shape of the lens is not limited to the arc. Instead of an arc of an ellipse,

[0032]

(Equation 1)

(Where x is the distance from the lens center in the pitch direction, C is the reciprocal of the radius of curvature, K is the conic constant, D, E,
F and G represent the coefficients of the fourth to tenth terms, respectively. ) May be used.

Further, in the above-described example, the radius of curvature Ri of the cylindrical lens constituting the incident-side lenticular lens 11 is reduced by several percent at the end of the sheet with respect to the center of the sheet (FIG. 1), or over the entire width of the sheet. FIG. 2 shows an example in which the distribution of the radius of curvature Ri of the cylindrical lens forming the incident-side lenticular lens or the boundary between adjacent cylindrical lenses forming the incident-side lenticular lens in the present invention. The distribution state of the lens depth, which is defined as the height from the lens trough to the top of the lens where the lens surface of the cylindrical lens protrudes most toward the light source, is not limited to this. Preferably, the lens depth of the incident-side lenticular lens at the center of the effective screen range of the rear projection screen constituted by using this lenticular lens sheet is hi ₀ , and the lens depth of the incident-side lenticular lens at the end of the effective screen range is the when the hi _1, so that the _{0.98 ≦ hi 1 / hi 0 ≦} 1.10 is satisfied is. This makes it possible to further reduce the color shift and improve the total light transmittance.

The lenticular lens sheet of the present invention
Like the conventional lenticular lens sheet, as shown in FIG. 6, it can be used for a rear projection screen in combination with a Fresnel lens. In this case, as the Fresnel lens, a lens conventionally used for a rear projection screen can be used.

The rear projection type screen using the lenticular lens sheet of the present invention can be used preferably not only for a CRT but also for an LCD or DMD as a light source, so that the total light transmittance can be increased. it can.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments.

Example 1 (1) Production of Lenticular Lens Sheet A lenticular lens sheet having the structure shown in FIG. 2 was produced by an extrusion molding method using a crowning roll. In this case, polymethyl methacrylate was used as a resin constituting the lenticular lens sheet.
As for the extrusion conditions, the die temperature was raised by 5 ° C. at the center of the die with respect to the periphery of the die, and the bank was increased by about 10% at the periphery with respect to the center of the roll.

Thus, the total height of the sheet = 1500 m
m, total width = 1000 mm, pitch (p) of the incident side lenticular lens 11 = 0.78 mm, approximate radius of curvature Ri ₀ = 0.
32 mm ellipse, ellipse with approximate radius of curvature Ri ₁ = 0.32 mm at the sheet end of the incident-side lenticular lens, pitch (p) of the exit-side lenticular lens sheet 12 =
0.36 mm, ellipse with approximate radius of curvature Ro ₀ = 0.22 mm at the center of the exit-side lenticular lens sheet, ellipse with approximate radius of curvature Ro ₁ = 0.22 mm at the sheet end of the exit-side lenticular lens sheet, lenticular lens Distance between lenses at the center of the sheet t _o = 0.9
A lenticular lens sheet having a length of 30 mm and a distance t ₁ between the ends of the lens of 0.930 mm was molded.

Next, the light absorbing layer 13 was printed on the molded lenticular lens sheet by a conventional method (stripe width 0.32 mm) to obtain the lenticular lens sheet of the example.

(2) Evaluation (2-1) Color shift A lens having a focal length f = 900 mm was prepared as a Fresnel lens, and a rear projection type screen was formed by combining the lens with the above-mentioned lenticular lens sheet (width about 125).
0mm, height about 950mm). This screen can be used with a commercially available rear-projection projector TV (T0SHIBA AMERICA CONS
UMER PRODUCTS., INC., Model name TP61E90). Then, an all white signal is input to the television set, and as shown in FIG. 3, a position (A) 600 mm left from the center of the screen 5 of the television set 20 in the horizontal direction.
Was observed at a position (B) in front of the screen at a distance of 3 m and a position (C) shifted 60 ° counterclockwise in the horizontal direction to evaluate the color shift as follows.

First, cover the blue and green light sources with a cover,
The emission luminance from the screen when the red light was emitted to the screen was measured at the position B (R ₀ [nit]). Next, the red and green light sources were covered with a cover, and the emission luminance of the blue light from the screen was measured in the same manner (B ₀ [ni
t]).

The measurement position was moved to the position C, and the emission luminance R ₆₀ [nit] of the red light and the emission luminance B ₆₀ [nit] of the blue light were measured in the same manner as the measurement at the position B.

Then, a color shift CS _{(600 mm, 60 °)} representing the magnitude of the color change at a position (A) 600 mm leftward from the center of the screen 5 was determined according to the following equation.

[0045]

## EQU2 ## CS _{(600 mm, 60 °)} = 20 log ((R ₆₀ / R ₀ ) /
(B ₆₀ / B ₀ )) [dB] The results are shown in Table 1.

(2-2) Total light transmittance As in the case of the color shift measurement described above, a lenticular lens sheet is attached to a rear projection type projector television, and 600 mm left from the center of the screen of this television set in the horizontal direction. ASTM for location
The total light transmittance _Tt was measured according to D-1003.

Table 1 shows the results.

Examples 2 to 6, Comparative Examples 1 to 3 Lenticular lens sheets having the shapes shown in Tables 1 and 2 were prepared in substantially the same manner as in the examples, and the color shift and the total light transmittance thereof were measured. . Tables 1 and 2 show these results.

[0049]

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Sheet central Reference Bu distance _{t 0 (mm) 0.930 ← ←} ← ← ← incident side Reference Bu _{Ri 0 (mm) 0.32 ← ←} ← ← ← emitted Side lens ゛ Ro ₀ (mm) 0.22 ← ← ← ← ← Sheet edge Reference Bu distance _{t x (mm) 0.930 0.925 0.940} 0.960 0.925 0.960 incident side Reference Bu _{Ri x (mm) 0.32 ← ←} ← 0.31 0.31 emitting side Reference Bu _{Ro x (mm) 0.22 ← ←} ← ← ← Color shift (dB) 7.5 8.0 7.5 7.0 8.0 7.0 Total light transmittance _Tt (%) 83 82 84 86 81 85

[0050]

[Table 2]

According to Tables 1 and 2, according to the lenticular lens sheet of the embodiment in which the distance between the lenses at the end of the sheet is 0.98 or more and 1.10 or less with respect to the distance between the lenses at the center of the sheet, the color shift can be reduced. It can be seen that the total light transmittance can be improved by reducing the total light transmittance.

[0052]

According to the lenticular lens sheet of the present invention, the color shift can be reduced.
It is possible to improve the total light transmittance of the sheet, prevent the light from being blurred, and improve the light use efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lenticular lens sheet of the present invention and a ray tracing diagram thereof.

FIG. 2 is a sectional view of a lenticular lens sheet according to another embodiment of the present invention and a ray tracing diagram thereof.

FIG. 3 is an explanatory diagram of a color shift measuring method.

FIG. 4 is a schematic configuration diagram of a general rear projection television.

FIG. 5 is an explanatory diagram of light rays in a general rear projection television.

FIG. 6 is a perspective view of a screen used in a general rear projection television.

FIG. 7 is a cross-sectional view of a conventional double-sided lenticular lens sheet.

FIG. 8 is a ray tracing diagram of a conventional double-sided lenticular lens sheet.

FIG. 9 is a cross-sectional view of a conventional single-sided lenticular lens sheet and a ray tracing diagram thereof.

[Explanation of symbols]

Reference Signs List 1 CRT 2 Projection lens 3 Fresnel lens 4 Lenticular lens sheet 5 Rear projection screen 10x Single-sided lenticular lens sheet 10, 10A, 10B Double-sided lenticular lens sheet 11 Incident-side lenticular lens 12 Exit-side lenticular lens 13 Light-absorbing layer 20 TV set

Claims (4)

[Claims] An incident side lenticular lens is provided on an incident side surface of a light beam, an exit side lenticular lens is provided on an exit side surface, and a top portion of the exit side lenticular lens is formed at a substantially condensing position of the incident side lenticular lens. In the double-sided lenticular lens sheet, the distance between the lenses, which is the distance between the top of the entrance-side lenticular lens and the top of the exit-side lenticular lens, is the center of the effective screen area of the rear projection screen configured using this lenticular lens sheet. the inter-lens distance t _0, the inter-lens distance in the effective screen range ends when the t _1, lenticular lens sheet, characterized in that it is satisfied _{0.98 ≦ t 1 / t 0 ≦} 1.10 . 2. From the center of the effective screen area of the screen,
When a distance between lenses at a position of a distance x in a direction orthogonal to the longitudinal direction of the cylindrical lens constituting the entrance-side lenticular lens is t (x), t (x) / t ₀ is within the effective screen area of the screen. 2. The lenticular lens sheet according to claim 1, wherein the lenticular lens sheet monotonously decreases or increases as x increases. 3. The lenticular lens sheet according to claim 1, which is formed by extrusion molding. 4. The lenticular lens sheet according to claim 3, wherein the crowning amount of the shaping roll used for extrusion molding is 20 μm or more per m.