JP2004109378A - Transmission type screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission type screen where the sudden change of brightness is not caused even when an observer's viewing point is changed in a perpendicular direction. <P>SOLUTION: The transmission type screen is equipped with a double-sided lenticular lens sheet 1 where a plurality of incident-side lenses 2 are formed and a plurality of emitting-side lenses 3 are formed at or near the condensing point of a light beam made incident on the incident-side lens. The screen uses the lenticular lens sheet at least incorporating (a) light diffusing particulates 5, 5' and 5" relatively increasing the gain of a skirt area where an observation angle is large, (b) light diffusing particulates relatively extending the gain of a top area where the observation angle is small and making a top part gentle, and (c) light diffusing particulates relatively increasing the gain of a middle area between the skirt area where the observation angle is large and the top area where it is small. At such a time, it is desirable that the respective light diffusing particulates (a) to (c) are silicone resin particulates, FMMA resin particulates and glass particulates. <P>COPYRIGHT: (C)2004,JPO

Description

【００２９】
実施例１の透過型スクリーンは、特有の光拡散特性を示す３種の光拡散性微粒子を混合しているので、観察角が大きい場合、小さい場合、および角度を変えた時の輝度変化の滑らかさの何れにおいても、良好な光拡散特性を示している。
【００３０】
一方、比較例１の透過型スクリーンは、図４に示すように裾の広い光拡散特性を示すことから、観察角が大きい場合の明るさに優れるものの、それ以外の評価は劣っている。比較例２の透過型スクリーンは、図５に示すように頂点部が拡大０た光拡散特性を示すことから、観察角の小さい場合の明るさに優れるものの、それ以外の評価は劣っている。比較例３の透過型スクリーンは、図６に示すように中間角度領域で高い利得を有する光拡散特性を示すことから、角度を変えた時の輝度変化は滑らかであるものの、それ以外の評価は劣っている。比較例４の透過型スクリーンは、図７に示すように観察角が大きい場合と小さい場合の明るさは良好であるが、中間角度領域での光拡散特性に劣っている。比較例５および比較例６の透過型スクリーンは、中間角度領域での明るさは良好であるが、それぞれ観察角が小さい場合と大きい場合の光拡散特性が劣っている。
【００３１】
【発明の効果】
以上説明したように、本発明の透過型スクリーンによれば、上述のａ）〜ｃ）の特徴を有する光拡散性微粒子が、垂直方向における観察角度の大きい裾領域の出射光を観察可能とし、垂直方向における観察角度の小さい頂上領域の突出した明るさを抑制し、さらに、垂直方向における観察角度の小さい頂上領域と大きい裾領域との間の中間領域における明るさの変化を滑らかにするよう作用するので、観察者の視点が垂直方向に変化した場合であっても、急激な明るさの変化が起こらないという格別の効果を奏する。こうした透過型スクリーンを備えるプロジェクションテレビジョンには、観察者に違和感を与えるホットバンドや暗部が現れず、明るく且つ広い角度から安心して観察できる。
【図面の簡単な説明】
【図１】本発明の透過型スクリーンが備えるレンチキュラーレンズシートの一例を示す断面構成図である。
【図２】本発明の透過型スクリーンの一例を示す構成図である。
【図３】本発明の透過型スクリーンの他の例を示す構成図である。
【図４】観察角度の大きい裾領域の利得を相対的に増加させるａ）光拡散性微粒子を含有させたレンチキュラーレンズシートの光拡散特性の一例を示すグラフである。
【図５】観察角度の小さい頂上領域の利得を相対的に拡大して頂上部をなだらかにするｂ）光拡散性微粒子を含有させたレンチキュラーレンズシートの光拡散特性の一例を示すグラフである。
【図６】観察角度の大きい裾領域と小さい頂上領域との間の中間領域の利得を相対的に増加させるｃ）光拡散性微粒子を含有させたレンチキュラーレンズシートの光拡散特性の一例を示すグラフである。
【図７】ａ）の光拡散性微粒子とｂ）の光拡散性微粒子を含有させたレンチキュラーレンズシートの光拡散特性の一例を示すグラフである。
【図８】ａ）〜ｃ）の拡散性微粒子を含有させたレンチキュラーレンズシートの光拡散特性の一例を示すグラフである。
【符号の説明】
１　レンチキュラーレンズシート
２　入射側レンズ
３　出射側レンズ
４　光拡散層
５、５’、５”　光拡散性微粒子
６　樹脂
７　ブラックストライプ
１１、２１、３１　透過型スクリーン
１２　フレネルレンズシート
１３　垂直拡散用レンチキュラーレンズを有するフレネルレンズシート
１４　垂直拡散用レンチキュラーレンズシート[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmissive screen used as a component of a projection television, and more particularly, to a transmissive screen in which a sudden change in brightness does not occur even when the observer's viewpoint changes vertically. It is about the screen.
[0002]
[Prior art]
A projection television is an image device that projects an image supplied from the rear side onto a transmission screen and observes an enlarged projection image transmitted through the screen from the near side. A lenticular lens sheet for widening a viewing angle in a horizontal direction and a vertical direction is used in a transmission screen used in such a projection television. The lenticular lens sheet is required to be bright and capable of observing from as wide an angle as possible.
[0003]
In the conventional lenticular lens sheet, for the purpose of expanding the viewing angle or suppressing the occurrence of extraordinary light, a specific type of lens having a refractive index slightly different from that of the synthetic resin constituting the lenticular lens sheet is used. Light diffusing fine particles have been incorporated into the exit lens surface and the entrance lens surface (see Patent Documents 1 and 2).
[0004]
[Patent Document 1]
JP-A-5-61120 (Claims)
[Patent Document 2]
JP-A-8-15780 (Claims)
[0005]
[Problems to be solved by the invention]
However, in the transmission type screen constituted by the above-described conventional lenticular lens sheet, a hot band (a band-like high-brightness region generated in the horizontal direction, which gives an observer discomfort) is observed, or the like. When the observer's viewpoint changes in the vertical direction, there are often areas that still cause discomfort to the observer, such as observing a region that is extremely dark when viewed from above the screen.
[0006]
The present invention has been made in order to solve the above-described problem, and an object of the present invention is to provide a transmission screen in which a sudden change in brightness does not occur even when the viewpoint of an observer changes in a vertical direction. Is to provide.
[0007]
[Means for Solving the Problems]
The present inventors have conducted further detailed studies based on the conventional knowledge that the light diffusion characteristics in the vertical direction mainly depend on the light diffusing fine particles, and as a result, the synthetic resin constituting the lenticular lens sheet has been obtained. In addition, by including a plurality of types of light diffusing fine particles corresponding to each observation angle in the vertical direction, even if the observer's viewpoint changes continuously in the vertical direction, a sudden change in brightness The inventors have found that this does not happen and arrived at the present invention.
[0008]
That is, the transmission screen of the present invention includes a double-sided lenticular lens sheet in which a plurality of entrance-side lenses are formed, and a plurality of exit-side lenses are formed at or near a light-converging point of light rays incident on the entrance-side lenses. In the transmissive screen, the lenticular lens sheet relatively increases at least a) the light diffusing fine particles that relatively increase the gain in the skirt region where the observation angle is large, and b) the gain in the top region where the observation angle is small. C) light-diffusing fine particles that make the top smooth, and c) light-diffusing fine particles that relatively increase the gain in the intermediate region between the bottom region having a large viewing angle and the small top region. Have.
[0009]
According to the present invention, the light-diffusing fine particles of a) act so as to enable the light emitted from the skirt region having a large observation angle in the vertical direction to be observed, and the light-diffusing fine particles of b) have a small observation angle in the vertical direction. The light diffusing fine particles of c) act to suppress the prominent brightness of the top region, and further smooth the change in brightness in the middle region between the top region and the large skirt region where the observation angle is small in the vertical direction. Acts to be. Since the transmission type screen of the present invention includes the lenticular lens sheet containing each light diffusing fine particle having such an action, even when the viewpoint of the observer changes in the vertical direction, a sharp change in brightness is observed. Does not happen.
[0010]
In the transmissive screen of the present invention, the light diffusing fine particles of a) have a refractive index difference of 0.08 or more with respect to the base material of the lenticular lens sheet, and the light diffusing fine particles of b) are the lenticular lens sheets. The difference in refractive index between the base material of the lens sheet and the base material of the lenticular lens sheet is 0.02 to 0.08. It is preferable that the light diffusing fine particles are silicone resin fine particles, PMMA resin fine particles, and glass fine particles.
[0011]
Further, in the transmission screen of the present invention, it is preferable that the light diffusing fine particles a) to c) are locally blended in the lenticular lens sheet. According to the present invention, since the lenticular lens sheet in which the light diffusing fine particles of a) to c) are locally blended into, for example, the exit lens, the incident light reaching the exit lens is appropriately diffused in the vertical direction. Can be done. As a result, it is possible to provide a transmissive screen in which the brightness does not suddenly change even when the observer's viewpoint changes in the vertical direction.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the transmission screen of the present invention will be described.
[0013]
As shown in FIG. 1, the transmission screen of the present invention has a plurality of incident-side lenses 2 and a plurality of outgoing-side lenses 3 formed at or near the focal point of light rays incident on the incident-side lenses 2. Lenticular lens sheet 1 provided. In the transmission screen of the present invention, the lenticular lens sheet 1 has at least a) light diffusing fine particles 5 which relatively increase the gain of a skirt region having a large observation angle, and b) a top region having a small observation angle. Light diffusing fine particles 5 'for increasing the gain relatively to smooth the top, and c) light diffusion for relatively increasing the gain in an intermediate region between the bottom region and the small top region where the observation angle is large. In particular, in the lenticular lens sheet 1, the light diffusing fine particles a) to c) are locally blended in the exit side lens 3 as shown in FIG. It is preferably formed as a light diffusion layer 4.
[0014]
The mode of the transmissive screen 11 of the present invention is not particularly limited as long as it has the lenticular lens sheet 1 having the above characteristics, and can be applied to various conventional screens. For example, as shown in FIG. 2, a transmissive screen 11 formed by combining a lenticular lens 1 and a Fresnel lens sheet 12, or as shown in FIG. 3B, and a lenticular lens 1, a lenticular lens sheet 14 for vertical diffusion, and a Fresnel lens sheet 12 as shown in FIG. 3B. The transmission screen 31 and the like can be exemplified.
[0015]
The synthetic resin 6 constituting the base material of the lenticular lens sheet 1 is not particularly limited as long as it is a synthetic resin having substantially transparency that can be used for the transmissive screen 11, that is, a light-transmitting synthetic resin. For example, acrylic resin, styrene resin, polycarbonate and the like are used. Above all, acrylic resins are preferably used because of their good surface scratch resistance, weather resistance, transparency and the like. Examples of such an acrylic resin include a resin mainly composed of methyl methacrylate, and a homopolymer of methyl methacrylate, or methyl methacrylate and methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, butyl acrylate, acrylonitrile, anhydrous Examples thereof include a copolymer with at least one of maleic acid, styrene and α-methylstyrene, or a mixture of a homopolymer of methyl methacrylate and the above copolymer. In addition, the synthetic resin may contain additives and the like having various functions and effects other than the light diffusing fine particles described later, as long as the object of the present invention is not impaired.
[0016]
The light-diffusing fine particles contained in the synthetic resin 6 include at least a) light-diffusing fine particles 5 that relatively increase the gain in a skirt region with a large observation angle, and b) gain in a top region with a small observation angle. Light-diffusing fine particles 5 'that relatively enlarges the top and smoothes the crest, and c) the light-diffusing property that relatively increases the gain in the intermediate region between the crest region and the crest region where the observation angle is large. Fine particles 5 ″. By adding at least three types of light diffusing fine particles having these light diffusing characteristics, a sharp change in brightness can be obtained even when the observer's viewpoint changes in the vertical direction. This does not occur, and the change in brightness can be made smooth.
[0017]
FIGS. 4 to 6 are graphs showing the light diffusion characteristics in the vertical direction of the lenticular lens sheet containing each of the light diffusing fine particles of the above a) to c) alone. This light diffusion characteristic is measured by a minute argument luminance meter, and the front surface of the lenticular lens sheet is set to 0 °, the horizontal axis is the vertical observation angle, and the vertical axis is the gain (also referred to as gain).
[0018]
FIG. 4 is a graph showing an example of a vertical light diffusion characteristic of a lenticular lens sheet containing light diffusing fine particles that relatively increase the gain of a skirt region having a large viewing angle. In this type of light diffusion characteristic, the width of the graph is narrow in the top region where the observation angle is small (for example, about −5 ° to + 5 °), and the gain is large in the bottom region where the observation angle is large (for example, about 10 ° to 40 °). The characteristic is that the top is sharp and the curve is wide. Examples of the light diffusing fine particles having such light diffusing characteristics include silicone resin fine particles. The light diffusing fine particles preferably have a refractive index difference of 0.08 or more from the base material of the lenticular lens sheet.
[0019]
FIG. 5 is a graph showing an example of the vertical light diffusion characteristics of a lenticular lens sheet containing light diffusing fine particles that relatively increase the gain of the top region where the observation angle is small and smooth the top. . In this type of light diffusion characteristic, the width of the graph is wide and gentle in the top region where the observation angle is small (for example, about -5 ° to + 5 °), but the skirt region where the observation angle is large (for example, about 10 ° to 40 °). The characteristic of ()) is that the gain is small, and the top is generally a curved line without a wide tail. Examples of the light diffusing fine particles exhibiting such light diffusing characteristics include PMMA (polymethyl methacrylate) resin fine particles. The light diffusing fine particles preferably have a refractive index difference of 0 to 0.02 with respect to the base material of the lenticular lens sheet.
[0020]
FIG. 6 shows an example of the vertical light diffusion characteristics of a lenticular lens sheet containing light diffusing fine particles that relatively increase the gain in an intermediate region between a large skirt region and a small crest region with a large viewing angle. It is a graph. This type of light diffusion characteristic has a large gain in an intermediate region between a top region having a small observation angle (for example, about -5 ° to + 5 °) and a skirt region having a large observation angle (for example, about 10 ° to 40 °). There is a feature that the light diffusion characteristics of the intermediate mode between FIGS. 4 and 5 are shown. Examples of the light diffusing fine particles having such light diffusing characteristics include glass fine particles. The light diffusing fine particles preferably have a refractive index difference of 0.02 to 0.08 with respect to the base material of the lenticular lens sheet.
[0021]
Next, the combinations of the light diffusing fine particles a) to c) described above will be described. FIG. 7 is a graph showing an example of the light diffusion characteristics in the vertical direction of a lenticular lens sheet containing the light diffusing fine particles a) and the light diffusing fine particles b). The lenticular lens sheet according to this combination has the feature of having the width of the skirt, which is the characteristic of the light diffusing fine particles of a), and the width of the top, which is the characteristic of the light diffusing fine particles of b). . Such a lenticular lens sheet has a drawback in that a sharp change in brightness is observed between a top region where the observation angle is small and a skirt region where the observation angle is large. FIG. 8 is a graph showing the light diffusion characteristics in the vertical direction of the lenticular lens sheet containing the light-diffusing fine particles of c) in this combination. This combination is a combination of the light-diffusing fine particles of a) to c), and becomes a graph having a certain spread in the middle region between the top region where the observation angle is small and the large skirt region. There is an unprecedented advantageous effect that brightness changes smoothly up to the large skirt region.
[0022]
The light diffusing fine particles contained in the lenticular lens sheet may contain one kind of each of the light diffusing fine particles of a) to c), or may contain one or two or more kinds of light diffusing fine particles, As a result, it can be preferably contained as long as it shows the light diffusion characteristic in the mode as shown in FIG.
[0023]
【Example】
Hereinafter, the transmission screen of the present invention will be described based on specific examples and comparative examples.
[0024]
(Example 1)
First, 0.2 parts by weight of silicone resin particles having an average particle diameter of 6 μm and a refractive index of 1.42, 1.2 parts by weight of glass particles having an average particle diameter of 10 μm and a refractive index of 1.56, and an average particle diameter of 30 μm and a refractive index of 1. For example, 3.0 parts by weight of 49 PMMA resin fine particles were used, and each of these light diffusing fine particles was mixed with 100 parts by weight of a PMMA-styrene copolymer resin having a refractive index of 1.51 to form an emission side lens layer. A co-extruded resin was prepared. Next, as the co-extruded resin for the incident side lens layer, a co-extruded resin prepared by setting the clearness of PMMA-styrene copolymer resin, which is the same base resin as above, to 50% was prepared. These resins were supplied to a co-extruder, and a lenticular lens sheet having a light diffusion layer was produced by a mold roll having a predetermined shape. The obtained lenticular lens sheet and a separately produced Fresnel lens sheet were bonded together to produce a transmission screen of Example 1 according to the present invention. FIG. 8 shows the light diffusion characteristics of the transmission screen of the first embodiment.
[0025]
(Comparative Examples 1 to 6)
As shown in Table 1, each type of light diffusing fine particles mixed in 100 parts by weight of the PMMA-styrene copolymer resin was changed in the same manner as in Example 1 except that the type of each light diffusing fine particle was changed. Light diffusing fine particles were selected as shown in Table 1, and transmission screens of Comparative Examples 1 to 6 were produced. 4 to 7 show the light diffusion characteristics of the transmission screens of Comparative Examples 1 to 4.
[0026]
(Measurement of light diffusion characteristics)
The light diffusion characteristics were measured by a micro deflector luminance meter, which is a device for measuring the luminance at each light beam emission angle. As shown in FIG. 4 to FIG. 8, the light diffusion characteristics are represented by the observation angle on the horizontal axis and the gain on the vertical axis. Then, each of the obtained transmissive screens was mounted on an actual projection television, and the change in brightness when the observation angle in the vertical direction was changed was observed. The results were compared with the results of the light diffusion characteristics shown in FIGS. It was evaluated.
[0027]
(Evaluation results)
[0028]
[Table 1]

[0029]
The transmissive screen of Example 1 contains three types of light diffusing fine particles exhibiting unique light diffusing characteristics. Therefore, when the observation angle is large, when the observation angle is small, and when the angle is changed, the luminance change is smooth. In each case, good light diffusion characteristics are shown.
[0030]
On the other hand, the transmissive screen of Comparative Example 1 exhibited light diffusion characteristics with a wide skirt as shown in FIG. 4, and thus was excellent in brightness when the observation angle was large, but poor in other evaluations. As shown in FIG. 5, the transmission screen of Comparative Example 2 exhibits light diffusion characteristics in which the apex is enlarged to zero, and thus has excellent brightness when the observation angle is small, but is inferior in other evaluations. The transmissive screen of Comparative Example 3 has a light diffusion characteristic having a high gain in the intermediate angle region as shown in FIG. 6, so that the luminance change when the angle is changed is smooth, but the other evaluations are Inferior. As shown in FIG. 7, the transmission screen of Comparative Example 4 has good brightness when the observation angle is large and small when the observation angle is small, but is inferior in light diffusion characteristics in an intermediate angle region. The transmissive screens of Comparative Example 5 and Comparative Example 6 have good brightness in the intermediate angle region, but have inferior light diffusion characteristics when the observation angle is small and large, respectively.
[0031]
【The invention's effect】
As described above, according to the transmission screen of the present invention, the light-diffusing fine particles having the above-described characteristics a) to c) enable the emission light in the skirt region having a large observation angle in the vertical direction to be observed, The effect of suppressing the prominent brightness of the top area where the observation angle is small in the vertical direction, and smoothing the change in brightness in the middle area between the top area where the observation angle is small in the vertical direction and the large skirt area. Therefore, even when the viewpoint of the observer changes in the vertical direction, a special effect that a sudden change in brightness does not occur is achieved. A projection television having such a transmissive screen does not show a hot band or a dark portion that gives a sense of incongruity to an observer, and can be viewed from a bright and wide angle without worry.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an example of a lenticular lens sheet provided in a transmission screen of the present invention.
FIG. 2 is a configuration diagram showing an example of a transmission screen of the present invention.
FIG. 3 is a configuration diagram showing another example of the transmission screen of the present invention.
FIG. 4 is a graph showing an example of a light diffusion characteristic of a lenticular lens sheet containing light diffusing fine particles for relatively increasing the gain of a skirt region having a large viewing angle.
FIG. 5 is a graph showing an example of a light diffusion characteristic of a lenticular lens sheet containing light diffusing fine particles in which the gain of a top region having a small observation angle is relatively enlarged to make the top smooth.
FIG. 6 is a graph showing an example of a light diffusion characteristic of a lenticular lens sheet containing light diffusing fine particles, which relatively increases a gain in an intermediate region between a skirt region having a large viewing angle and a small crest region. It is.
FIG. 7 is a graph showing an example of the light diffusion characteristics of a lenticular lens sheet containing the light diffusing fine particles a) and the light diffusing fine particles b).
FIG. 8 is a graph showing an example of the light diffusion characteristics of a lenticular lens sheet containing the diffusing fine particles of a) to c).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lenticular lens sheet 2 Incident side lens 3 Outgoing side lens 4 Light diffusion layer 5, 5 ', 5 "Light diffusing fine particle 6 Resin 7 Black stripes 11, 21, 31 Transmission screen 12 Fresnel lens sheet 13 Vertical lenticular lens Lens sheet 14 having a lenticular lens sheet for vertical diffusion

Claims (4)

In a transmission screen including a double-sided lenticular lens sheet in which a plurality of incident-side lenses are formed, and a plurality of exit-side lenses are formed at or near the light-converging point of light rays incident on the incident-side lenses,
The lenticular lens sheet has at least a) light diffusing fine particles for relatively increasing the gain of a skirt region having a large viewing angle, and b) relatively increasing the gain of a top region having a small viewing angle to make the top smooth. And c) light-diffusing fine particles for relatively increasing the gain in an intermediate region between a skirt region having a large viewing angle and a crest region having a small viewing angle. The light diffusing fine particles a) have a refractive index difference of 0.08 or more with respect to the base material of the lenticular lens sheet, and the light diffusing fine particles b) have a refractive index difference with the base material of the lenticular lens sheet. The index difference is 0 to 0.02, and the light diffusing fine particles of c) have a refractive index difference of 0.02 to 0.08 with respect to the base material of the lenticular lens sheet. 2. The transmission screen according to 1. 3. The transmission screen according to claim 1, wherein the light diffusing fine particles of a) to c) are silicone resin fine particles, PMMA resin fine particles, and glass fine particles. The transmissive screen according to any one of claims 1 to 3, wherein the light diffusing fine particles (a) to (c) are locally blended in the lenticular lens sheet.

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