JP2007240918A - Lens sheet, transmission-type screen, and back projection type video display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission type screen which is diagonally arranged with pixels and can display the video from a light source projecting video light high fineness, while vibrating and is satisfactory in productivity. <P>SOLUTION: The transmission-type screen 10 is equipped with a lens sheet 20 which diffuses the light incident from a back side and emits the light to an observation side. The lens sheet 20 has a plurality of lens elements 22, formed on an incident side side 20a and external light absorption sections 24, which are disposed in the portions not transmitting the light condensed by the lens elements 22 of the exit side surface 20b, are so formed as to protrude to the observation side and are colored on the surface so as to absorb the external light. The arrangement pitch P of the lens elements 22 is 0.30 mm or larger and 0.57 mm or smaller. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rear projection type video display device having a light source, a transmissive screen used in the rear projection type video display device, and a lens sheet used in the transmissive screen. The present invention relates to a rear projection image display device including a light source for projecting light, a transmissive screen suitable for the light source, and a lens sheet suitable for the light source.

  A rear projection type image display device displays an image on a transmissive screen by enlarging and projecting image light from a three-tube CRT light source, a liquid crystal light source or a DLP light source having pixels arranged regularly in the vertical and horizontal directions, etc. Device. In recent trends, liquid crystal light sources and DLP light sources have been used more widely than three-tube CRT light sources.

  The items required for the transmissive screen differ depending on the type of light source. For example, a transmission screen that displays image light from a CRT light source has been required to alleviate problems caused by light being projected from three locations. In addition, a transmission type screen that displays an image from a liquid crystal light source or a DLP light source is required to alleviate problems caused by the image being composed of light for each pixel. More specifically, the arrangement pitch of the lens elements of each lens sheet constituting the transmissive screen is determined according to the pixel pitch of the light source, and the image is displayed with high definition, and the light and lens elements divided for each pixel are used. Moire should not be caused due to interference with the focused light.

Various research and development have been conducted on transmission screens that display images from liquid crystal light sources or DLP light sources, and various research and development have been conducted on manufacturing methods thereof (for example, Patent Document 1). Patent Document 1 discloses a method of manufacturing a lenticular lens sheet that is one lens sheet constituting a transmission screen. As disclosed in Patent Document 1, a lenticular lens sheet used for a transmission type screen that displays an image from a liquid crystal light source or a DLP light source cannot be manufactured by a molding process such as an extrusion process. Since it is molded through the process, there is a problem that the manufacturing cost of the transmission screen including the lenticular lens sheet becomes expensive.
JP 2001-113538 A

  On the other hand, recently, in order to make the boundary between pixels of an image projected from a liquid crystal light source or a DLP light source inconspicuous, a light source for projecting image light while oscillating pixels and vibrating is being developed. Accordingly, it is necessary to develop a transmission screen that does not impair the characteristics of such a light source. In this case, it is preferable to develop a transmissive screen with good productivity, unlike the conventional transmissive screen.

  The present invention has been made in consideration of such points, and can display a high-definition image from a light source that projects image light while the pixels are arranged obliquely and vibrates, and has high productivity. An object is to provide a high transmission screen and a lens sheet.

  In addition, the present invention provides a rear projection type video display device that includes a light source that projects video light while the pixels are obliquely arranged and vibrates, and that can display video with high definition and high productivity. Objective.

  Recently, the present inventor has conducted extensive research, projecting image light while the light source vibrates, and the pixels of the light source are arranged obliquely. As a result, it was found that the moiré is less likely to occur. The present invention is mainly based on such knowledge.

  The lens sheet according to the present invention is used in a rear projection type image display device including a light source that projects image light while obliquely arranging pixels and vibrating, and diffuses light incident from the back side and emits it to the observation side. A lens sheet, which is provided on a portion of the exit-side surface where light collected by the lens element is not transmitted, and is formed so as to protrude toward the observation side. And an external light absorbing portion colored so as to absorb external light, and the arrangement pitch of the lens elements is 0.20 mm or more and 0.57 mm or less.

  According to such a lens sheet, an image can be displayed with high definition. Moreover, such a lens sheet can be easily and inexpensively manufactured by extrusion molding and coloring the external light absorbing portion.

  In the lens sheet according to the present invention, it is preferable that the arrangement pitch of the lens elements is 0.20 mm or more and 0.38 mm or less. As a result, even when the number of pixels of the light source is large, a high-definition image corresponding to the number of pixels of the light source can be displayed.

  In the lens sheet according to the present invention, a portion of the emission side surface where the external light absorbing portion is formed may be separated from the lens element by substantially the same length as the focal length of the lens element. According to such a lens sheet, it is possible to increase the ratio of the external light absorbing portion on the exit side surface of the lens sheet without reducing the light transmittance. Thereby, the contrast of the displayed image can be improved.

  Further, in the lens sheet according to the present invention, a diffusing element for diffusing light may be formed in a portion of the exit side surface through which light collected by the lens element is transmitted. According to such a lens sheet, scintillation can be reduced.

  The transmissive screen according to the present invention is a transmissive screen used in a rear-projection video display device including a light source that projects video light while pixels are arranged obliquely and vibrates. The lens sheet is provided.

  According to such a transmission screen, it is possible to display an image with high definition. Moreover, the lens sheet included in the transmission screen can be easily and inexpensively manufactured by extrusion molding and coloring the external light absorbing portion. As a result, the transmission screen can be easily and inexpensively manufactured.

  The transmissive screen according to the present invention further includes an optical sheet disposed on the observation side of the lens sheet, and the optical sheet has a diffusion layer containing light diffusing particles that diffuse light transmitted through the optical sheet. You may do it. According to such a transmission screen, scintillation can be reduced. In addition, the scintillation can be effectively reduced by adding the light diffusing particles to the optical sheet disposed on the observation side of the lens sheet, rather than including the light diffusing particles in the lens sheet.

  Further, in the transmissive screen according to the present invention, the optical sheet is disposed with respect to the lens sheet so that the exit side surface of the diffusion layer is separated from the lens element by at least twice the focal length of the lens element. You may do it. According to such a transmissive screen, the image light is transmitted through the entire region of the exit side surface of the diffusion layer, and the image light can be diffused by the light diffusion particles. Thereby, scintillation can be reduced efficiently.

  Furthermore, in the transmissive screen according to the present invention, the lens sheet and the optical sheet are bonded via an adhesive, and the adhesive contains light diffusing particles that diffuse light transmitted through the adhesive. You may make it. Furthermore, the transmission screen according to the present invention further includes a Fresnel lens sheet disposed on the back side of the lens sheet, and a diffusion element for diffusing light is formed on the surface of the Fresnel lens sheet. Also good. Further, the transmission screen according to the present invention further includes a Fresnel lens sheet disposed on the back side of the lens sheet, and the Fresnel lens sheet contains light diffusing particles that diffuse light transmitted through the Fresnel lens sheet. You may make it do. In these cases, scintillation can be reduced. In addition, it is possible to reduce the amount of light diffusing particles contained in the optical sheet while maintaining scintillation resistance, and to increase the contrast of the image displayed on the transmission screen without deteriorating the scintillation.

  A rear projection image display device according to the present invention includes any one of the above-described transmission screens, and a light source that projects image light while oscillating pixels and vibrating. According to such a rear projection type image display device, an image can be displayed with high definition. Moreover, the lens sheet included in the transmission screen can be easily and inexpensively manufactured by extrusion molding and coloring the external light absorbing portion. As a result, the rear projection type image display device can be manufactured easily and inexpensively.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  1 to 6 are views showing an embodiment of a transmission screen 10 according to the present invention. 1 is a sectional view showing an embodiment of a transmission screen 10 according to the present invention, FIG. 2 is a perspective view showing the transmission screen 10, and FIG. 3 is a rear projection incorporating the transmission screen 10. As shown in FIG. FIG. 4 to FIG. 6 are cross-sectional views showing a transmissive screen 10.

  As shown in FIGS. 1 to 3, the transmissive screen 10 is used as a screen of the rear projection image display device 1, and the image light projected from the light source 3 and reflected by the mirror 5 is projected onto the transmissive screen 10. It is like that. As shown in FIG. 1, the light source 3 projects image light while vibrating, and each pixel when projected onto the transmission screen is arranged diagonally, that is, along a diagonal line. Yes. The light source 3 vibrates only in one direction, for example, and the vibration cycle is 50 Hz to 150 Hz.

  The transmissive screen 10 according to the present embodiment includes a Fresnel lens sheet 12 disposed closest to the light source 3, a lens sheet (lenticular lens sheet, light diffusion sheet) 20 disposed on the observation side of the Fresnel lens sheet 12, and And an optical sheet 30 disposed on the observation side of the lens sheet 20.

  Of these, the Fresnel lens sheet 12 has Fresnel lens elements 13 arranged concentrically, refracts the image light enlarged and projected from the light source 3, and emits light in a direction substantially orthogonal to the Fresnel lens sheet 12. It is supposed to be. However, the Fresnel lens sheet 12 is not essential and may be omitted depending on the performance required for the transmission screen 10.

  Next, the lens sheet 20 will be described in detail.

  The lens sheet 20 is arranged in parallel with the Fresnel lens sheet 12 and is for diffusing the image light incident from the back side in the width direction and emitting it to the observation side (FIG. 1). The lens sheet 20 includes a plurality of incident-side lens elements 22 for expanding the viewing angle formed on the incident-side surface 20a, and a portion of the output-side surface 20b through which light collected by the incident-side lens element 20a does not pass. The external light absorbing part 24 that absorbs external light and the light collected by the incident side lens element 22 on the outgoing side surface 20b are provided so as to protrude to the observation side. A light transmitting portion 26. In the present embodiment, since the lens sheet 20 diffuses light in the width direction (lateral direction), the incident-side lens element 22, and accordingly, the external light absorbing unit 24 and the light transmitting unit 26. Are provided at a predetermined arrangement pitch along the width direction (FIG. 2).

  As shown in FIG. 1, at least the observation-side surface 24 a that forms the emission-side surface 20 b of the lens sheet 20 itself is colored in the external light absorbing portion 24. The color to be colored is preferably black so that external light can be efficiently absorbed. In addition, as shown in FIG. 1, since the part of the external light absorption part 24 is formed so that it may protrude rather than another part among the output side surfaces 20b, a coloring process is easy to the surface of the external light absorption part 24 Can be applied.

  Further, as shown in FIG. 4, the exit side surface 20b of the external light absorbing portion 24 of the lens sheet 20 extends from the incident side lens element 22 in the thickness direction by substantially the same length as the focal length L1 of the incident side lens element 22. It is preferred that they are spaced apart along. In other words, the separation distance L2 along the thickness direction between the observation-side surface 24a of the external light absorber 24 (the colored surface of the external light absorber) 24a and the incident-side lens element 22 is the incident-side lens element 22. Is preferably substantially the same as the focal length L1. In this case, even if the ratio of the external light absorbing portion 24 on the emission side surface 20b of the lens sheet 22 is increased, it is possible to prevent the external light absorbing portion 24 from absorbing light transmitted through the lens sheet 20. Because it can. Thereby, outside light can be absorbed more without lowering the light transmittance, and the contrast of the image displayed on the transmissive screen 10 can be improved.

  Incidentally, in such a lens sheet 20, the arrangement pitch P of the incident side lens elements 22 is determined so as to satisfy the following conditions.

  First, it is preferable that the arrangement pitch P of the incident side lens elements 22 is 1 / 1.5 or less of the arrangement pitch of the pixels of the light source 3 so that an image according to the number of pixels of the light source 3 can be displayed finely. .

  For example, a rear projection type image display apparatus that has a screen size of 50 inches, an aspect ratio of 9:16, and the number of pixels arranged in the vertical direction of the light source 3 is 720 pixels, which is becoming a standard performance in recent years. Let's consider 1. In this case, the screen width (horizontal length) is approximately 1107 mm, and the number of pixels arranged in the horizontal direction (width direction) is approximately 1280 pixels, which is along the width direction of the image displayed on the transmissive screen 10. The pixel arrangement pitch P is about 0.865 mm. Therefore, the arrangement pitch of the incident side lens elements 22 is preferably 0.57 or less. Further, similarly, in the high-performance rear projection image display device 1 having a screen size of 50 inches, an aspect ratio of 9:16, and a number of pixels arranged in the vertical direction of the light source 3 of 1080 pixels. The arrangement pitch P of the incident side lens elements 22 is preferably 0.38 mm or less.

  Next, in consideration of the productivity of the transmission screen 10, it is preferable that the lens sheet 20 can be formed by extrusion. In order to form the concavo-convex shape of the lens sheet 20 by extrusion processing, the arrangement pitch P of the incident side lens elements 22 is preferably 0.20 mm or more, and in order to form more reliably, it is 0.30 mm or more. It is preferable. In general, when the arrangement pitch P is reduced, the resin enters the mold, and the thickness of the lens sheet must be reduced as the arrangement pitch P is reduced. For this reason, if the arrangement pitch P of the incident side lens elements 22 is reduced, the manufacture of the lens sheet 20 becomes extremely difficult, and the productivity is remarkably deteriorated. When the arrangement pitch P of the incident side lens elements 22 is less than 0.20 mm, the lens sheet 20 formed by the extrusion process does not have a desired cross-sectional shape. In this case, the lens sheet 20 does not have a desired light diffusion performance, and the viewing angle of the transmissive screen becomes narrower than a predetermined angle.

  From the above, the arrangement pitch P of the incident side lens elements 22 is preferably 0.20 mm or more and 0.57 mm or less, and preferably 0.20 mm or more and 0.38 mm or less, or 0.30 mm or more and 0.57 mm or less. More preferably, it is still more preferably 0.30 mm or more and 0.38 mm or less. Such a lens sheet 20 can be efficiently manufactured by extruding a thermoplastic resin and then performing a coloring process on the observation-side surface 24a of the external light absorption unit 24 by, for example, die coating. That is, the productivity of the lens sheet 22 can be significantly improved.

  As shown in FIG. 1, in the present embodiment, the transmission screen 10 further includes an optical sheet 30 disposed on the observation side of the lens sheet 20. By providing this optical sheet 30, the rigidity of the transmission screen 10 is increased, and the self-supporting property of the transmission screen 10 is improved. Furthermore, the optical sheet 30 in the present embodiment has a diffusion layer 32 containing a plurality of light diffusion particles 34 for diffusing light emitted from the lens sheet 20 and transmitted through the optical sheet 30. Therefore, the light diffused so as to expand the viewing angle by the lens sheet 20 can be diffused more irregularly (without directivity). As a result, scintillation can be prevented, and the viewing angle in the direction that cannot be diffused by the lens sheet 20 (vertical direction in the present embodiment) can also be increased.

  As shown in FIG. 5A, the exit side surface 32 a of the diffusion layer 32 is separated from the incident side lens element 22 of the lens sheet 20 along the thickness direction at least twice the focal length L <b> 1 of the incident side lens element 22. As described above, the optical sheet 30 is preferably disposed with respect to the lens sheet 20. In other words, the separation distance L3 along the thickness direction between the incident side lens element 22 of the lens sheet 20 and the emission side surface 32a of the diffusion layer 32 is at least twice the focal length L1 of the incident side lens element 22 of the lens sheet 20. It is preferable that When not arranged in this way, as shown in FIG. 5B, a portion R where no light is emitted is generated on the emission side surface 20b of the diffusion layer 32, and the light diffusion particles 34 are used efficiently. This is because not only light cannot be diffused, but also the image displayed on the transmissive screen 10 may be uneven. That is, the emission side surface 32a of the diffusion layer 32 is disposed so that the emission side surface 32a of the diffusion layer 32 is separated from the incident side lens element 22 of the lens sheet 20 by at least twice the focal length L1 of the incidence side lens element 22. The image light is transmitted through the entire area of the image, and the image light can be diffused by the light diffusion particles 34. Thereby, scintillation can be reduced efficiently.

  Note that the optical sheet 30 may be held integrally with the lens sheet 20 by fixing the edges thereof to each other with a frame or the like, or may be fixed and held on the entire surface of the lens sheet 20 via an adhesive.

  Further, the optical sheet 30 is not limited to the mode (FIG. 5) constituted only by the diffusion layer 32, but may further include a layer having another optical action (for example, an external light antireflection layer), a protective layer, or the like. The optical sheet possessed can be used. As an example, the optical sheet 30 shown in FIG. 6 has a thin diffusion layer 32 and the diffusion layer 32 spaced apart from the incident side lens element 22 of the lens sheet 20 by a certain distance in the thickness direction. And a transparent resin layer 36 for increasing rigidity.

  As described above, according to the present embodiment, the arrangement pitch P of the incident side lens elements 22 of the lens sheet 20 is used in the transmissive screen 10 used together with the light source 3 that projects image light while the pixels are arranged obliquely and vibrated. Is within a predetermined range. As a result, it is possible to display an image with high definition without causing moire. Further, the lens sheet 20 of such a transmission screen 10 can be manufactured by extrusion molding and coloring the surface 24a on the observation side of the external light absorbing portion 24, whereby the lens sheet can be manufactured. Easy and inexpensive. In particular, in the present embodiment, the lens sheet 20 does not contain the light diffusing particles 34, and is formed from one type of thermoplastic resin except for the coloring material that colors the external light absorbing portion 24. Therefore, the extrusion processability is also very good.

  Further, according to the present embodiment, the exit-side surface 20b of the external light absorbing portion 24 of the lens sheet 20 extends in the thickness direction from the incident-side lens element 22 by substantially the same length as the focal length L1 of the incident-side lens element 22. Therefore, the ratio of the external light absorbing portion 24 on the emission side surface 20b of the lens sheet 20 can be increased without absorbing the light transmitted through the lens sheet 20. Thereby, the contrast of the image displayed on the transmissive screen 10 can be improved without reducing the light transmittance.

  Furthermore, according to the present embodiment, the transmission screen 10 further includes an optical sheet 30 disposed on the observation side of the lens sheet 20, and the optical sheet 30 diffuses light transmitted through the optical sheet 30. It has a diffusion layer 32 containing a plurality of light diffusion particles 34. Therefore, it is not necessary to include the light diffusing particles 34 in the lens sheet 20, whereby the lens sheet 20 can be formed from one type of thermoplastic resin except for the coloring material that colors the external light absorbing portion 24. Extrudability is very good. In addition, the scintillation can be further reduced when the optical sheet 30 arranged on the observation side of the lens sheet 20 contains the light diffusing particles 34 than when the lens sheet 20 contains the light diffusing particles 34.

  Furthermore, according to the present embodiment, the optical sheet 30 is arranged such that the exit side surface 32a of the diffusion layer 32 is separated from the incident side lens element 22 of the lens sheet 20 by at least twice the focal length L1 of the incident side lens element 22. Is disposed with respect to the lens sheet 20. Accordingly, the image light is transmitted through the entire surface of the emission side surface 32 a of the diffusion layer 32, and the image light can be diffused by the light diffusion particles 34. Thereby, scintillation can be further reduced efficiently.

  Next, a modification of the present embodiment will be described with reference to FIGS. 7 to 10, the same parts as those of the transmissive screen 10 according to the present embodiment described with reference to FIGS. 1 to 6 are denoted by the same reference numerals and redundant description is omitted.

  In the present embodiment, an example in which the light diffusing particles 34 are contained only in the optical sheet 30 has been shown, but the present invention is not limited to this. As shown in FIG. 7, the lens sheet 20 and the optical sheet 30 are bonded via an adhesive 40, and a plurality of light diffusing particles 34 for diffusing the light transmitted through the adhesive 40 by the adhesive 40. It may be made to contain.

  According to such a transmission screen 10, the adhesive layer 42 composed of the adhesive 40 and the light diffusing particles 34 also has a light diffusing effect, and scintillation can be further reduced. In this case, since the external light absorbing portion 24 of the lens sheet 20 protrudes to the observation side, the adhesive layer 42 between the external light absorbing portion 24 of the lens sheet 20 and the optical sheet 30 becomes thin, and accordingly. The amount of the light diffusing particles 34 intervening therebetween becomes a very small amount. Therefore, most of the light diffusing particles 34 in the adhesive layer 42 are interposed between the light transmitting portion 26 of the lens sheet 20 and the optical sheet 30 and are efficiently used to diffuse the light emitted from the lens sheet 20. It is done.

  On the other hand, it is possible to reduce the amount of the light diffusing particles 34 contained in the optical sheet 30 while maintaining the scintillation resistance by containing the light diffusing particles 34 in the adhesive 40. In this case, only a small amount of light diffusing particles 34 is present in the adhesive layer 42 facing the external light absorbing portion 24 of the lens sheet 20, and the amount of light diffusing particles 34 in the optical sheet 20 is reduced. Therefore, the external light absorption unit 24 can absorb external light more efficiently. That is, the contrast of the image displayed on the transmissive screen 10 can be further increased without deteriorating scintillation.

  Further, in the present embodiment, a light diffusion portion 26 having an arcuate contour in a cross-sectional view is provided in a portion of the exit side surface 20b of the lens sheet 20 through which light collected by the entrance side lens element 22 is transmitted. An example is shown, but the present invention is not limited to this. As shown in FIG. 8, a planar light transmission portion 29 having a linear outline in a cross-sectional view may be formed in a portion of the emission side surface 20 b through which the collected light is transmitted. Furthermore, a diffusing element 28 for diffusing light is formed in the arc-shaped light transmitting portion 26 or the linear light transmitting portion 29 provided in a portion through which the collected light is transmitted for the purpose of reducing scintillation. May be. In the transmissive screen 10 shown in FIG. 9, the lens sheet 20 and the optical sheet 30 are bonded together by an adhesive 40 having a refractive index different from that of the lens sheet 20, and the light emitted from the condensed light of the lens sheet 20 is emitted. A diffusion element 28 having an uneven shape is formed on the side surface 20b. In such a transmissive screen 10, an interface is formed between the lens sheet 20 and the adhesive layer 42, and light emitted from the lens sheet 20 is refracted and diffused at this interface. Thereby, scintillation can be further reduced.

  On the other hand, it is also possible to reduce the amount of the light diffusing particles 34 to be contained in the optical sheet 30 while maintaining the scintillation resistance by giving the light diffusing effect to the exit side surface 20b of the lens sheet 20. In this case, since the amount of the light diffusing particles 34 in the optical sheet 30 is reduced, the external light absorber 24 can absorb external light more efficiently. That is, the contrast of the image displayed on the transmissive screen 10 can be further increased without deteriorating scintillation.

  In addition, the unevenness | corrugation of the spreading | diffusion element 28 may be formed regularly, and may be formed irregularly.

  Furthermore, in the present embodiment, an example in which the transmissive screen 10 includes the Fresnel lens sheet 12 disposed on the back side of the lens sheet 20 has been described. In order to diffuse light on the surface of the Fresnel lens sheet 12. The diffusion element 14 may be formed, or a plurality of light diffusion particles 34 for diffusing the light transmitted through the Fresnel lens sheet 12 may be included in the Fresnel lens sheet 12. In the transmissive screen 10 shown in FIG. 10, an example is shown in which the diffusing element 14 having an uneven shape is provided on the incident side surface 12 a of the Fresnel lens sheet 12 and the light diffusing particles 34 are contained in the Fresnel lens sheet 12. The diffusing element 14 is not limited to the incident side surface 12a of the Fresnel lens sheet 12, but may be formed on the emission side surface 12b or both the incident side surface 12a and the emission side surface 12b. Moreover, the unevenness | corrugation of the spreading | diffusion element 14 may be formed regularly, and may be formed irregularly.

  According to such a transmissive screen 10, the Fresnel lens sheet 12 also has a light diffusion effect, and scintillation can be further reduced. On the other hand, it is possible to reduce the amount of the light diffusing particles 34 contained in the optical sheet 30 while maintaining the scintillation resistance by giving the Fresnel lens sheet 12 a light diffusing effect. In this case, since the amount of the light diffusing particles 34 in the optical sheet 30 is reduced, the external light absorber 24 can absorb external light more efficiently. That is, the contrast of the image displayed on the transmissive screen 10 can be further increased without deteriorating scintillation.

  Hereinafter, specific examples of the above-described embodiment of the present invention will be described.

  A transmissive screen composed of a Fresnel lens, a lens sheet, and an optical sheet shown in FIG. 1 and having a screen size of 50 inches and an aspect ratio of 9:16 was manufactured. For the lens sheet, MBS (methacrylstyrene butadiene copolymer resin) available from Sumitomo Chemical Co., Ltd. under the trade name “Sumipex HW” is extruded, and then the surface on the observation side of the external light absorption part is blackened by die coating. Colored.

  In addition, the arrangement pitch of the incident side lens elements of the lens sheet is 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm, 0.55 mm, and Ten types of 0.60 mm were manufactured. About each lens sheet, the cross section was confirmed using the optical microscope.

  In addition, the display state of the transmissive screen was confirmed using a light source that projects image light while the pixels are arranged obliquely and vibrate. Two types of light sources were tested: a light source with 720 pixels in the vertical direction and a light source with 1080 pixels in the vertical direction.

The evaluation criteria were as follows.
1. Section 1.1. Shape ○: A desired cross-sectional shape was obtained.
Δ: A substantially desired cross-sectional shape was obtained.
X: The desired cross-sectional shape was not obtained.
1.2. Coloring position ○: The surface on the observation side of the external light absorbing portion was accurately colored.
X: The coloring position was shifted.

2. Display state 2.1. Clarity ○: The image was displayed with high definition.
Δ: The image was displayed finely.
X1: The viewing angle was narrow.
× 2: The resolution was poor 2.2. Contrast ○: Good.
X: Not good.

The evaluation results are as shown in Table 1.

Sectional drawing which shows one Embodiment of the transmission type screen by this invention. The perspective view which shows a transmissive screen. The perspective view which shows the rear projection type video display apparatus incorporating a transmissive screen. Sectional drawing which shows the lens sheet of a transmissive screen. Sectional drawing which shows the lens sheet and optical sheet of a transmissive screen. Sectional drawing which shows the lens sheet and optical sheet of a transmissive screen. Sectional drawing which shows the modification of a transmissive screen. Sectional drawing which shows the modification of a transmissive screen. Sectional drawing which shows the modification of a transmissive screen. Sectional drawing which shows the modification of a transmissive screen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rear projection type image display apparatus 3 Light source 10 Transmission type screen 12 Fresnel lens 14 Diffusion element 20 Lens sheet 20a Incident side surface 20b Emission side surface 22 Incident side lens element 24 External light absorption part 26 Light transmission part 28 Diffusion element 29 Light transmission Part 30 Optical sheet 32 Diffusion layer 34 Light diffusion particle 40 Adhesive L1 Focal length

Claims (11)

In a lens sheet that is used in a rear projection type image display device provided with a light source that projects image light while the pixels are arranged obliquely and vibrates, in a lens sheet that diffuses light incident from the back side and emits it to the observation side,
A plurality of lens elements formed on the incident side surface;
An outside light absorbing portion provided on a portion of the emission side surface that does not transmit the light collected by the lens element and formed to protrude to the observation side and colored to absorb outside light; Prepared,
A lens sheet, wherein the arrangement pitch of the lens elements is 0.20 mm or more and 0.57 mm or less.   The lens sheet according to claim 1, wherein an arrangement pitch of the lens elements is 0.20 mm or more and 0.38 mm or less.   3. The part according to claim 1, wherein a portion of the emission-side surface where the external light absorbing portion is formed is separated from the lens element by substantially the same length as a focal length of the lens element. Lens sheet.   The diffusion element for diffusing light is formed in the part which the light condensed by the said lens element permeate | transmits among the light emission side surfaces, The Claim 1 thru | or 3 characterized by the above-mentioned. Lens sheet. A transmissive screen used in a rear projection type image display device including a light source that projects image light while pixels are arranged obliquely and vibrates,
A transmissive screen comprising the lens sheet according to claim 1. An optical sheet disposed on the observation side of the lens sheet;
The transmissive screen according to claim 5, wherein the optical sheet has a diffusion layer containing light diffusing particles that diffuse light transmitted through the optical sheet.   The optical sheet is disposed with respect to the lens sheet so that an exit side surface of the diffusion layer is separated from the lens element by at least twice the focal length of the lens element. The transmissive screen as described. The lens sheet and the optical sheet are bonded via an adhesive,
The transmissive screen according to claim 6 or 7, wherein the adhesive contains light diffusing particles that diffuse light transmitted through the adhesive. Further comprising a Fresnel lens sheet disposed on the back side of the lens sheet,
The transmissive screen according to any one of claims 5 to 8, wherein a diffusion element for diffusing light is formed on a surface of the Fresnel lens sheet. Further comprising a Fresnel lens sheet disposed on the back side of the lens sheet,
The transmissive screen according to any one of claims 5 to 8, wherein the Fresnel lens sheet contains light diffusion particles that diffuse light transmitted through the Fresnel lens sheet. The transmissive screen according to any one of claims 5 to 10,
A rear projection type image display device comprising: a light source that projects image light while pixels are arranged obliquely and vibrate.

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