JP3525776B2 - Rear projection screen - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear projection type screen composed of three optical elements of a Fresnel lens, a vertical lenticular lens and a horizontal lenticular lens, and a pitch of pixels projected on the screen surface, The present invention relates to a rear projection screen characterized in that the moire phenomenon occurring between the above three optical elements is significantly reduced.

[0002]

2. Description of the Related Art A rear projection type screen used in an image projection apparatus for magnifying and projecting an image of a projection tube, a liquid crystal panel or the like on a screen and observing from the front has a Fresnel lens plate as shown in FIG. It consists of a horizontal wrench and a lens plate. The Fresnel lens plate is used to direct the light emitted from the projector in the direction of the observer, that is, to brighten the screen.
On the other hand, the horizontal lenticular lens plate is used to spread the light emitted from the projector in the left-right direction of the viewer, that is, to widen the observation area so that many people can observe. Further, for the purpose of improving the contrast, as shown in FIG. 1, black stripes are generally arranged in parallel on a flat portion corresponding to the non-condensing portion of the lenticular lens on the observation surface of the horizontal lenticular lens plate. Target.

In the case of a rear projection type screen comprising a conventional Fresnel lens plate and a horizontal lenticular lens plate, there are two Fresnel lens plates having a constant pitch concentric circular pattern and two horizontal lenticular plates having a constant pitch vertical linear pattern. Moire that occurs when the layers are overlapped becomes a problem.

As a method for reducing the above-mentioned moire phenomenon, it has been considered to form fine irregularities on a Fresnel lens plate or a lenticular lens plate, or to mix a light diffusing agent into the Fresnel lens plate or the lenticular lens plate. However, when the moire phenomenon is severe, it cannot be said to be an effective means, and it is difficult to significantly suppress the moire.

In view of such a situation, Japanese Patent Laid-Open No. 57-19
1627, JP-A-59-140433, JP-A-59
As described in the patent publications such as -95525,
When the pitch of the Fresnel lens plate is 1, the pitch ratio with the lenticular lens plate is N + 1.35 to 1.4
A method has been proposed in which the pitch ratio between the lenticular lens plate and the Fresnel lens plate is set within a certain range such that the range is 3 or 1 / (N + 1.35 to 1.43) (where N is a natural number). There is.

On the other hand, in the case of a rear projection type screen consisting of a conventional Fresnel lens plate and a horizontal lenticular lens plate, the horizontal lenticular lens does not have a lens action in the vertical direction, so that the screen is constructed. The observation area in the vertical direction is widened by such means as mixing a light diffusing agent into the base material or applying the light diffusing agent to the surface of the base material. However, as the diffusing agent, for example, inorganic fine powder such as silica, alumina, titanium oxide, and glass powder, or organic fine powder such as cross-linked polymer fine particles is used, which reduces the light transmittance of the screen. There was a problem of inviting.

In order to solve this problem, in a conventional rear projection type screen composed of a Fresnel lens and a horizontal lenticular lens, a vertical lenticular lens having a function of refracting image projection light in a vertical direction without using a light diffusing agent. By adding the element of the vertical lenticular lens that widens the observation area in the vertical direction to the conventional rear projection type screen, the rear projection type screen consisting of three optical elements of Fresnel lens, horizontal lenticular lens and vertical lenticular lens Proposed.

In contrast to the conventional rear projection type screen composed of a Fresnel lens and a horizontal lenticular lens, a vertical lenticular lens having a function of refracting image projection light in the vertical direction is used without using a light diffusing agent. A vertical lenticular lens element that expands the observation area is added to the conventional rear projection type screen, and in the rear projection type screen composed of three optical elements of Fresnel lens, horizontal lenticular lens and vertical lenticular lens, There has been a demand for a rear projection type screen in which moiré is significantly reduced in consideration of moiré with pixels of an image to be projected.

However, as described above, while the proposal for reducing the moire generated between the two optical elements of the Fresnel lens plate and the horizontal lenticular lens plate constituting the rear projection type screen, the rear projection is used. A Fresnel lens having a constant pitch concentric circular pattern forming a formula screen, a vertical lenticular lens having a linear pattern of horizontally arranging a constant pitch, and a linear pattern of vertically arranging a constant pitch. Conventionally, no means has been taken to significantly reduce moiré in consideration of the moiré phenomenon that occurs when the three optical elements of the horizontal lenticular lens that it has are superimposed and the pixel pitch that is projected onto the screen surface. .

[0010]

SUMMARY OF THE INVENTION According to the present invention, a Fresnel lens having a function of condensing image projection light on an observation side, a vertical lenticular lens having a function of refracting in the vertical direction, and a function of refracting in the horizontal direction are provided. In a rear projection screen composed of three optical elements of a horizontal lenticular lens, a pixel of an image projected on the screen surface, a Fresnel lens forming the rear projection screen, a vertical lenticular lens, and a horizontal lenticular lens. It is an object of the present invention to provide a rear projection type screen characterized by significantly reducing the moire phenomenon that occurs between the respective optical elements.

[0011]

The present inventor has made the following equation 28
From the ratio of the pitch of the lenticular lens plate and the pitch of the optical elements such as Fresnel lens plate, the size of the moire is calculated, and after careful examination, the pixels of the image projected on the screen surface and the rear projection screen are configured. The present invention has been achieved by finding a pitch of a vertical lenticular lens in which moire between the Fresnel lens and the vertical lenticular lens is not noticeable.

[0012]

[Equation 28]

[0013]

That is, the invention according to claim 1 is directed to image projection.
A Fresnel lens that has the function of converging the emitted light to the observation side,
Vertical lenticular that has the effect of refracting in the vertical direction
Lens and a horizontal wrench that refracts in the horizontal direction.
Rear projection consisting of three optical elements of a muller lens
Image projected on the screen surface of a digital screen
Pixels and constant pitch that makes up the rear projection screen
Fresnel lens with concentric circular pattern and horizontal
Of vertical stripes with a constant pitch linear pattern
Moire generated between the optical element and the
The phenomenon, the pitch of the Fresnel lens P1, the pixel pitch is P2, P1 <P2,1 ≦ n ≦ 6,1 ≦ m
Under the condition of ≦ 29 (excluding multiples of 5), when the following formula 1 is satisfied, the vertical lenticular lens is
Between the Fresnel lens and the pixel is represented pitch area group moire is not generated by the following equation 2-5, there in vertical lenticular Kiyura over lenses having a pitch selected from among the one group of regions And markedly reduced
It is a rear projection type screen .

[0015]

[Equation 29]

[0016]

[Equation 30]

[0017]

[Equation 31]

[0018]

[Equation 32]

[0019]

[Expression 33]

According to a second aspect of the invention, the image projection light is observed.
Fresnel lens that has the function of focusing light to the side, and in the vertical direction
Vertical lenticular lens with refracting action and water
Horizontal lenticular that has the effect of refracting in the horizontal direction
Rear-projection scree consisting of three optical elements
Image pixels projected on the screen surface,
Concentric circles with constant pitch that make up a rear projection screen
Arrange horizontally with patterned Fresnel lens
Vertical wrench with a constant pitch filament pattern
-For the moire phenomenon occurring between the lens and each optical element, the pitch of the Fresnel lens is P1, and the pixel pitch is P.
2 and P1 < P2, 1 ≦ n ≦ 6, 1 ≦ m ≦ 29 (excluding a multiple of 5), when the following expression 6 is satisfied, the vertical lenticular lens is A pitch region group in which no moire is generated between the Fresnel lens and the pixel is represented by the following formulas 7 to 12, and (A) a pitch selected from any of the region groups satisfying formula 7, or (B )
A vertical lenticular lens having a pitch selected from any of the region groups satisfying formulas 8 to 11 or (C) a pitch selected from any of the region groups satisfying formula 12 . Rear projection type, characterized by being significantly reduced
The screen .

[0021]

[Equation 34]

[0022]

[Equation 35]

[0023]

[Equation 36]

[0024]

[Equation 37]

[0025]

[Equation 38]

[0026]

[Formula 39]

[0027]

[Formula 40]

According to a third aspect of the invention, the image projection light is observed.
Fresnel lens that has the function of focusing light to the side, and in the vertical direction
Vertical lenticular lens with refracting action and water
Horizontal lenticular that has the effect of refracting in the horizontal direction
Rear-projection scree consisting of three optical elements
Image pixels projected on the screen surface,
Concentric circles with constant pitch that make up a rear projection screen
Arrange horizontally with patterned Fresnel lens
Vertical wrench with a constant pitch filament pattern
-For the moire phenomenon occurring between the lens and each optical element, the pitch of the Fresnel lens is P1, and the pixel pitch is P.
2 and P1 < P2, 1 ≦ n ≦ 6, 1 ≦ m ≦ 29 (excluding a multiple of 5), when the following expression 13 is satisfied, the vertical lenticular lens is A pitch area group in which no moire is generated between the Fresnel lens and the pixel is represented by the following expressions 14 to 20, and (A) a pitch selected from any area group satisfying expression 14 or (B) ) A vertical lenticular lens having a pitch selected from any of the region groups satisfying the formulas 15 to 17 or (C) a pitch selected from any of the region groups satisfying the formulas 18 to 20. There is a significant reduction
It is a rear projection type screen .

[0029]

[Formula 41]

[0030]

[Equation 42]

[0031]

[Equation 43]

[0032]

[Equation 44]

[0033]

[Equation 45]

[0034]

[Equation 46]

[0035]

[Equation 47]

[0036]

[Equation 48]

According to a fourth aspect of the invention, the image projection light is observed.
Fresnel lens that has the function of focusing light to the side, and in the vertical direction
Vertical lenticular lens with refracting action and water
Horizontal lenticular that has the effect of refracting in the horizontal direction
Rear-projection scree consisting of three optical elements
Image pixels projected on the screen surface,
Concentric circles with constant pitch that make up a rear projection screen
Arrange horizontally with patterned Fresnel lens
Vertical wrench with a constant pitch filament pattern
-For the moire phenomenon occurring between the lens and each optical element, the pitch of the Fresnel lens is P1, and the pixel pitch is P.
2 and P1 < P2, 1 ≦ n ≦ 6, 1 ≦ m ≦ 29 (excluding multiples of 5), when the following expression 21 is satisfied, the vertical lenticular lens is A pitch region group in which no moire is generated between the Fresnel lens and the pixel is represented by the following formulas 14 to 20, and (A) formula 22 to
A pitch selected from any of the region groups satisfying 24,
Alternatively, (B) a vertical lenticular lens having a pitch selected from the group of regions satisfying the expressions (25) to (27), which is remarkably reduced.
The screen .

[0038]

[Equation 49]

[0039]

[Equation 50]

[0040]

[Equation 51]

[0041]

[Equation 52]

[0042]

[Equation 53]

[0043]

[Equation 54]

[0044]

[Equation 55]

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

FIG. 1 is a perspective view showing an example of the structure of a rear projection type screen having a conventional two-piece structure including a Fresnel lens plate and a horizontal lenticular lens plate. Also,
FIG. 2 is a perspective view showing an example of the configuration of a rear projection screen including three optical elements including a Fresnel lens, a horizontal lenticular lens, and a vertical lenticular lens according to the present invention.

FIG. 3 is a graph showing the pitch ratio of optical elements and the size of moire from the following equation 56. That is, in order to make the moire inconspicuous to the minimum, the wavelength becomes the minimum at the intersection of the n-th and (n + 1) th-order moire wavelength curves. The minimum intersection is 2 / (2n + 1)
(N: positive integer). That is, 2/3, 2
The values are / 5, 2/7, 2/9, 2/11, 2/13, etc. Moire is inconspicuous if the pitch ratio between the two optical elements is the above value or less. In order to suppress the moire wavelength within 1.5 times in order to reduce moire, the pitch ratio is ± 5%.

[0048]

[Equation 56]

When the pitch ratio is a value of 1 or more, 1
+ (2m / 10) (m: positive integer, except for multiples of 5), that is, the pitch ratio is 1. 2, 1. 4,
1. 6, 1. The values will be 8, 2.2, 2.4, etc. Moire is inconspicuous if the pitch ratio between the optical elements is at or above the above values. In order to suppress the moire wavelength within 1.5 times in order to reduce moire, the pitch ratio is ± 0.03.

Hereinafter, as an example, the pixel pitch (P2) is 0.973 mm and the Fresnel lens pitch (P1) is 0.
In case of 100 mm, P1 < P2, 1 ≦ n ≦ 6, 1 ≦ m
Under the condition of ≦ 29 (excluding a multiple of 5), when the following expression 6 is satisfied, the vertical lenticular lens defines a pitch area group in which no moire occurs between the Fresnel lens and the pixel. It was calculated. The results are shown in Tables 1 and 2.

[0051]

[Equation 57]

[0052]

[Table 1]

[0053]

[Table 2]

From the results shown in Table 1, it is sufficient to consider the moire only with the Fresnel lens as the finer pitch, so the pitch of the vertical lenticular lens is 0.06.
33-0.0700, 0.0380-0.0420,
It is selected from the range of 0.0271 to 0.0300 ...

Further, since it is necessary to consider the moire of both the optical elements of the pixel and Fresnel lens for the coarser pitch,
0.1176-0.1223, 0.1372-0.14
30, 0.1570-0.1572, 0.1770
0.1830, 0.2170 to 0.2230, 0.27
70 to 0.2830, etc. are selected. Moire can be reduced by combining pitches that are multiples that can be expressed by the above two expressions.

Examples of the base material of the lenticular lens plate and Fresnel lens plate used in the rear projection screen of the present invention include acrylic resin, polycarbonate resin, styrene resin, acrylic-styrene copolymer resin, vinyl chloride resin and the like. It is not particularly limited. When using these synthetic resin base materials, a lenticular lens plate and a Fresnel lens plate can be manufactured by extrusion molding or hot flat press molding. Further, an ultraviolet curable resin layer is provided only on the lens portion of the lenticular lens plate and the Fresnel lens plate on the surface of the base material, the resin layer is superposed on a mold having a shape opposite to the lens, and the transparent resin substrate side is formed. It is also possible to produce a lenticular lens plate and a Fresnel lens plate by irradiating the resin layer with ultraviolet rays or the like to cure the resin layer and molding the lens portion on the surface of the base material.

The lenticular lens plate and the Fresnel lens plate used in the rear projection screen of the present invention may be composed of transparent base materials, and the base material may be, for example, silica, alumina, titanium oxide, inorganic fine particles such as glass powder. At least one of a lenticular lens plate and a Fresnel lens plate, or a light diffusing agent of an organic fine powder such as a powder or crosslinked polymer fine particles is mixed, or the light diffusing agent is made into an ink.
It may be applied and formed on a desired surface. The use of the light diffusing agent has an auxiliary effect on the suppression of moire, but it is desirable that the amount of the diffusing agent used is as small as possible.

Next, a specific example will be described. A transparent acrylic resin plate is used, and a horizontal lenticular lens plate with a pitch of 0.160 mm and a Fresnel lens with a concentric pattern with a pitch of 0.100 mm are formed on one surface of the transparent acrylic resin plate. A double-sided lens plate composed of a Fresnel lens and a lenticular lens formed by molding a 0.040 mm vertical lenticular lens was prepared by a desired method. The Fresnel lens surface of this double-sided lens plate and the lenticular lens surface of one of the horizontal lenticular lens plates are overlapped, and the rear projection type screen of the present invention comprising three optical elements of a Fresnel lens, a horizontal lenticular lens and a vertical lenticular lens. Got Regarding the degree of recognition of moire in the rear projection screen of the present invention, it was confirmed that the moire was significantly reduced and the moire was not noticeable.

[0059]

According to the present invention, the moire phenomenon which occurs between the image pixels projected on the screen surface, the Fresnel lens forming the rear projection type screen, the vertical lenticular lens and the horizontal lenticular lens is suppressed. It is possible to provide a bright rear projection screen with a wide viewing area in the vertical direction, which is composed of three optical elements: a significantly reduced Fresnel lens, a vertical lenticular lens, and a horizontal lenticular lens.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a configuration of a conventional rear projection type screen.

FIG. 2 is a perspective view showing an example of a configuration of a rear projection type screen of the present invention.

FIG. 3 is a graph showing the relationship between the pitch ratio of two optical elements and the size of moire.

[Explanation of symbols]

1. Rear projection screen 2. Fresnel lens 3. Vertical lenticular lens 4. Horizontal lenticular lens 5. Black stripe

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-62-236282 (JP, A) JP-A-62-121436 (JP, A) JP-A-60-263932 (JP, A) JP-A-58- 93044 (JP, A) JP 8-36224 (JP, A) JP 7-114107 (JP, A) JP 5-297338 (JP, A) JP 5-142658 (JP, A) JP-A-3-168630 (JP, A) JP-A-3-149540 (JP, A) JP-A-2-97991 (JP, A) Actual development: 3-37437 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 21/62

Claims (4)

(57) [Claims] 1. A function of condensing image projection light on an observation side.
A Fresnel lens and a vertical lens that refracts vertically.
Direct lenticular lens and function to refract in the horizontal direction
From the three optical elements of the horizontal lenticular lens with
In the rear-projection screen configured, the pixels of the image projected on the screen surface and the rear-projection screen
Has a concentric pattern with a constant pitch that constitutes a clean
Fresnel lens and horizontal pitch
With a vertical wrench killer lens with a linear pattern of
Regarding the moire phenomenon occurring between the optical elements, the pitch of the Fresnel lens is P1, the pixel pitch is P2, and P1 <P2, 1 ≦ n ≦ 6, 1 ≦ m ≦ 29 (excluding a multiple of 5). When the following expression 1 is satisfied under the condition of, the vertical lenticular lens is represented by the following expression 2 to 5 as a pitch area group in which no moire is generated between the Fresnel lens and the pixel, A rear projection screen, which is a vertical lenticular lens having a pitch selected from any of the area groups, which is remarkably reduced . [Equation 1] [Equation 2] [Equation 3] [Equation 4] [Equation 5] 2. A function of condensing image projection light on an observation side.
A Fresnel lens and a vertical lens that refracts vertically.
Direct lenticular lens and function to refract in the horizontal direction
Three optical elements of a horizontal Renchikyu Rarenzu with
In the rear-projection screen configured, the pixels of the image projected on the screen surface and the rear-projection screen
Has a concentric pattern with a constant pitch that constitutes a clean
Fresnel lens and horizontal pitch
With a vertical wrench killer lens with a linear pattern of
Regarding the moire phenomenon occurring between the optical elements, the pitch of the Fresnel lens is P1, the pixel pitch is P2, and P1 <P2, 1 ≦ n ≦ 6, 1 ≦ m ≦ 29 (excluding a multiple of 5). When the following expression 6 is satisfied under the condition of, the vertical lenticular lens is represented by the following expressions 7 to 12 as a pitch area group in which no moire is generated between the Fresnel lens and the pixel: (A) Pitch selected from any of the region groups that satisfy Expression 7, or (B)
A vertical lenticular lens having a pitch selected from any of the region groups satisfying formulas 8 to 11 or (C) a pitch selected from any of the region groups satisfying formula 12 . Rear projection screen characterized by being significantly reduced [Equation 6] [Equation 7] [Equation 8] [Equation 9] [Equation 10] [Equation 11] [Equation 12] 3. A function of condensing image projection light on an observation side.
A Fresnel lens and a vertical lens that refracts vertically.
Direct lenticular lens and function to refract in the horizontal direction
From the three optical elements of the horizontal lenticular lens with
In the rear-projection screen configured, the pixels of the image projected on the screen surface and the rear-projection screen
Has a concentric pattern with a constant pitch that constitutes a clean
Fresnel lens and horizontal pitch
With a vertical wrench killer lens with a linear pattern of
Regarding the moire phenomenon occurring between the optical elements, the pitch of the Fresnel lens is P1, the pixel pitch is P2, and P1 <P2, 1 ≦ n ≦ 6, 1 ≦ m ≦ 29 (excluding a multiple of 5). When the following expression 13 is satisfied under the condition of, the pitch region group in which the vertical lenticular lens does not generate moire between the Fresnel lens and the pixel is represented by the following expressions 14 to 20, (A) Pitch selected from any of the region groups satisfying the formula 14, (B) Pitch selected from any of the region groups satisfying the formulas 15 to 17, or (C) Formula 18 to A rear projection screen, which is a vertical lenticular lens having a pitch selected from any of the region groups satisfying 20 and is significantly reduced . [Equation 13] [Equation 14] [Equation 15] [Equation 16] [Equation 17] [Equation 18] [Formula 19] [Equation 20] 4. A function of condensing image projection light on the observation side.
A Fresnel lens and a vertical lens that refracts vertically.
Direct lenticular lens and function to refract in the horizontal direction
From the three optical elements of the horizontal lenticular lens with
In the rear-projection screen configured, the pixels of the image projected on the screen surface and the rear-projection screen
Has a concentric pattern with a constant pitch that constitutes a clean
Fresnel lens and horizontal pitch
With a vertical wrench killer lens with a linear pattern of
Regarding the moire phenomenon occurring between the optical elements, the pitch of the Fresnel lens is P1, the pixel pitch is P2, and P1 <P2, 1 ≦ n ≦ 6, 1 ≦ m ≦ 29 (excluding a multiple of 5). When the following expression 21 is satisfied under the condition of, the vertical lenticular lens is represented by the following expressions 14 to 20 as a pitch region group in which the moire does not occur between the Fresnel lens and the pixel, (A) Formula 22-
A pitch selected from any of the region groups satisfying 24,
Alternatively, (B) a vertical lenticular lens having a pitch selected from any of the group of regions satisfying Formulas 25 to 27, which is remarkably reduced, and is a rear projection screen. [Equation 21] [Equation 22] [Equation 23] [Equation 24] [Equation 25] [Equation 26] [Equation 27]