JP4867167B2 - Transmission screen and rear projection display device - Google Patents

Description

  The present invention relates to a transmissive screen and a rear projection display device.

  A rear projection television is known as a rear projection display device having a transmissive screen. The rear projection TV projects video light from a projector as a light source, reflects it by a reflecting mirror, and makes it incident on the back of a transmissive screen having a substantially rectangular flat plate shape. Thereby, the observer located in front of the transmission screen can observe the transmitted image light.

  FIG. 4 is a plan sectional view of a transmission screen according to the prior art. In the transmissive screen 920, a Fresnel lens array 30 that converts image light into substantially parallel light is disposed on the light source side, and a lenticular lens array (diffuse lens array) 40 that divides the image light for each unit lens is disposed on the viewer side. (See, for example, Patent Documents 1 and 2).

The Fresnel lens array 30 includes a Fresnel lens 31 disposed on the viewer side of the base material 32 and a first diffusion plate 33 mounted on the light source side of the base material 32. The first diffusion plate 33 ensures the self-supporting property (rigidity) of the Fresnel lens array 30.
On the other hand, the lenticular lens array 40 includes a base material 42 made of a light transmissive material and a lenticular lens 41 arranged on the light source side. A light shielding layer 45 is formed on the viewer side of the substrate 42, and the second diffusion plate 43 is fixed via an adhesive 44 disposed so as to cover the light shielding layer 45.
Then, both are fastened together by a frame body (not shown) arranged at the peripheral edge of the Fresnel lens array 30 and the lenticular lens array 40 to form a transmission type screen 920.

As described above, in the conventional transmissive screen 920, the first diffusion plate 33 is disposed in the Fresnel lens array 30 and the second diffusion plate 43 is disposed in the lenticular lens array 40. This prevents video scintillation. Scintillation is a phenomenon in which the brightness of the image light changes with the change of the observer's viewpoint, and the image looks glaring. As described above, by arranging the thick first diffusion plate 33 and the second diffusion plate 43 at a predetermined distance, the luminance distribution of the image light can be averaged to prevent image scintillation. It has become.
JP 2002-236319 A US Pat. No. 6,307,675 Japanese Patent No. 3002477 Japanese Utility Model Publication No. 1-111734

  The first diffusion plate 33 of the Fresnel lens array 30 described above is formed relatively thick. Therefore, the transmissive screen 920 becomes heavy and the cost is increased. In addition, when the first diffusion plate 33 is thick, the focus of the transmission screen 920 is reduced, and the resolution and sharpness are deteriorated.

  Thus, the formation of a film of the Fresnel lens array 30 has been studied (see, for example, Patent Documents 3 and 4). This is because the first diffusion portion is formed by roughening the surface of the light source side of the base material 32, the first diffusion plate 33 is eliminated, and the Fresnel lens array 30 is thinned to a thickness of 0.8 mm or less. It is. Thereby, the transmissive screen 920 can be lightened and reduced in cost. In addition, the resolution and sharpness of the transmissive screen 920 can be improved.

However, by providing the first diffusing portion instead of the first diffusing plate 33, the distance from the second diffusing plate 43 is reduced. As a result, video scintillation may occur.
The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a transmission screen that can prevent scintillation of an image even when a Fresnel lens array is formed into a film.
It is another object of the present invention to provide a rear projection display device with excellent display quality.

To achieve the above object, the transmissive screen according to the present invention, a Fresnel lens array to convert the movies image light into substantially parallel light is arranged on the light source side, a diffusing lens array for diverging the image light for each unit lens A transmissive screen arranged on an observer side, wherein the Fresnel lens array is formed in a film shape, and a first diffusing portion for diffusing the image light is formed on a light source side of the Fresnel lens array. The surface of the light source side is formed by matting and roughening, and in the vicinity of the imaging position on the observer side of the diffusion lens array, a second diffusion unit for diffusing the image light has optical transparency. A third diffusing portion for diffusing the image light on the viewer side of the second diffusing portion, which is formed by dispersing a light diffusing material or attaching a diffusing film of a predetermined thickness inside the resinous adhesive. Before Characterized in that it is formed by matting treatment to roughening the surface of the light source side of the supporting substrate to ensure the rigidity of the diffusion lens array.
According to this configuration, even when the luminance distribution of the image light is generated by diffusing the image light in the second diffusing unit disposed in the vicinity of the image light image formation position, the image light is disposed away from the image formation position. In addition, by diffusing the image light in the first diffusion unit and the third diffusion unit, the luminance distribution of the image light can be averaged. Therefore, scintillation of the video can be prevented.

Moreover, on the viewer side of said second diffusion portion and this transparent member is fixed is desirable.
According to this configuration , the rigidity of the diffusing lens array can be secured by the support substrate, and image scintillation can be prevented.

In addition, a transparent member having a predetermined thickness is fixed to the observer side of the second diffusing portion, and a support substrate for ensuring the rigidity of the diffusing lens array is disposed on the observer side of the transparent member. It is desirable that the three diffusion portions are formed on the light source side surface of the support substrate.
According to this configuration, the rigidity of the diffusing lens array can be secured by the support substrate, and image scintillation can be prevented. In addition, since the distance between the second diffusing portion and the third diffusing portion can be appropriately set depending on the thickness of the transparent member, it is possible to prevent the occurrence of blurring in the image.

The distance between the first diffusion part and the third diffusion part is preferably 2 mm or more.
According to this configuration, scintillation of video can be reliably prevented.

On the other hand, a rear projection display device according to the present invention includes the above-described transmission screen.
According to this configuration, since the transmissive screen capable of preventing the scintillation of the video is provided, it is possible to provide a rear projection type display device having excellent display quality.

  According to the transmission screen of the present invention, even when the luminance distribution of the image light is generated by diffusing the image light in the second diffusion unit arranged in the vicinity of the image light image formation position, By diffusing the image light in the first diffusing unit and the third diffusing unit that are arranged apart from each other, the luminance distribution of the image light can be averaged. Therefore, scintillation of the video can be prevented.

(First embodiment)
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.
(Rear projection type display device)
FIG. 1 is a side sectional view of a rear projection television which is an example of a rear projection display device. A rear projection television 10 shown in FIG. 1 includes a projector 12 as a light source for projecting image light, reflecting mirrors 13 and 14 that reflect image light, and a transmissive screen 20 that allows image light to be incident from the back and emitted from the front. The casing 11 is mainly configured to cover the whole while exposing the front of the transmission screen 20 to the outside.

(Transparent screen)
FIG. 2 is a plan sectional view of the transmission screen according to the first embodiment. In general, the transmissive screen 20 includes a Fresnel lens array 30 that converts image light into substantially parallel light on the light source side, and a lenticular lens array (diffuse lens array) 40 that divides the image light for each unit lens on the viewer side. It is arranged and configured. In particular, in the transmissive screen 20 according to the first embodiment, the Fresnel lens array 30 is formed in a film shape, and on the light source side of the Fresnel lens array 30, a first diffusion unit 34 that diffuses image light is formed. In the vicinity of the imaging position on the viewer side of the lenticular lens array 40, a second diffusion unit 46 that diffuses image light is formed. A support substrate 50 that secures the rigidity of the lenticular lens array 40 is fixed to the observer side of the second diffusion part 46, and a third diffusion part 52 is formed on the observer side surface of the support substrate 50. Yes.

(Fresnel lens array)
The Fresnel lens array 30 is configured by arranging a plurality of Fresnel lenses 31 on the light source side of the substrate 32. The base material 32 is formed in a horizontally long and substantially rectangular shape by a light-transmitting material such as polyethylene terephthalate (PET). The Fresnel lens 31 is configured by concentrically arranging protrusions made of a resin material having photocurability and light transmission properties such as acrylic. The Fresnel lens 31 refracts the image light incident on the portion, converts it into substantially parallel light, and emits it. Therefore, each Fresnel lens 31 includes an inclined surface corresponding to the incident angle of the image light.

On the other hand, a first diffusion part 34 is formed on the light source side of the substrate 32. The first diffusion part 34 is formed by subjecting the surface of the base material 32 on the light source side to mat processing and roughening the surface. The first diffusion portion 34 may be formed by attaching a diffusion film to the light source side of the substrate 32. Such a Fresnel lens array 30 is formed in a film shape having a thickness of about 0.2 to 0.8 mm.

  In order to manufacture this Fresnel lens array 30, first, one side of a PET film to be a base material 32 is roughened. In addition, you may use the PET film by which the single side | surface was roughened previously. Next, the base material 32 is placed in a mold in which the reverse shape of the Fresnel lens 31 is formed, and a photocurable resin is filled. Then, light is irradiated from the back surface of the substrate 32 to cure the photocurable resin, thereby forming the Fresnel lens array 30. It is also possible to continuously form the Fresnel lens array 30 using a roll in which the reverse shape of the Fresnel lens 31 is formed.

(Lenticular lens array)
On the other hand, the lenticular lens array 40 is configured by arranging a plurality of lenticular lenses 41 on the light source side of the substrate 42. The base material 42 is formed in a horizontally-oriented substantially rectangular shape with a light-transmitting material such as polyethylene terephthalate (PET). The lenticular lens 41 is a substantially semi-cylindrical cylindrical lens made of a resin material or the like having photo-curing and light-transmitting properties such as acrylic. A plurality of lenticular lenses 41 are arranged in parallel in the horizontal direction of the screen such that the longitudinal direction of the lenticular lens 41 is aligned with the vertical direction of the screen. In addition, the arrangement pitch of each lenticular lens 41 is set to 1.0 mm or less (preferably 0.2 mm or less), and the lenticular lens array 40 having a fine pitch is configured.

  A light shielding layer 45 made of a light absorbing material is provided on the viewer side of the base material 42. The light shielding layer 45 is a surface on the viewer side of the base material 42 and is formed in stripes on the non-condensing portion of the image light by the lenticular lens 41. A second diffusion portion 46 is formed so as to cover the light shielding layer 45. The second diffusing portion 46 is configured by dispersing a light diffusing material such as silica in a resin adhesive having light permeability, and is formed in the vicinity of the image light imaging position by the lenticular lens 41. The second diffusion portion 46 may be formed by attaching a diffusion film having a predetermined thickness on the viewer side of the base material 42.

  Further, a support substrate 50 is mounted on the viewer side of the base material 42 with an adhesive constituting the second diffusion part 46 interposed therebetween. The support substrate 50 is made to have a thickness of about 1 to 2 mm by a light transmissive material such as a copolymer of methyl methacrylate (MMA) and styrene (MS), polymethyl methacrylate (PMMA), or glass. Is formed. A third diffusion portion 52 is formed on the viewer side of the support substrate 50. The third diffusing portion 52 is formed by subjecting the surface of the support substrate 50 on the viewer side to mat processing and roughening the surface. The third diffusion part 52 may be formed by attaching a diffusion film to the viewer side of the support substrate 50.

(Fixed structure)
A sealant (not shown) is disposed on the peripheral edge of the Fresnel lens array 30 so that the Fresnel lens array 30 and the lenticular lens array 40 are fixed. Moreover, the peripheral part between both is airtightly sealed by the sealing agent, and the space enclosed by the sealing agent is formed in the center part between both. The internal pressure of this space is set lower than the external pressure. This prevents the central portion of the Fresnel lens array 30 formed in a film form from floating from the lenticular lens array. As a result, the disturbance of the optical path of the image light is prevented, the image light can be imaged at a predetermined position, and the occurrence of blur in the image can be prevented.

  The fixing structure of the Fresnel lens array 30 and the lenticular lens array 40 is not limited to the above. For example, an adhesive is disposed on the tops of a plurality of Fresnel lenses 31 constituting the Fresnel lens array 30, and the Fresnel lens is formed by the adhesive. The array 30 and the lenticular lens array 40 may be fixed. Alternatively, a line of adhesive may be arranged in a lattice pattern on the surface of the Fresnel lens array 30, and the Fresnel lens array 30 and the lenticular lens array 40 may be fixed by the adhesive.

  As described above, the transmission screen 20 according to the present embodiment is configured. The screen 20 is secured by a support substrate 50 disposed on the observer side of the lenticular lens array 40.

  In the transmissive screen 20 according to the present embodiment, three diffusion parts are formed, that is, the first diffusion part 34 of the Fresnel lens array 30 and the second diffusion part 46 and the third diffusion part 52 of the lenticular lens array 40. Has been. Among them, the second diffusion part 46 functions as a main diffusion part, and the first diffusion part 34 and the third diffusion part 52 function as secondary diffusion parts. The distance from the first diffusion part 34 to the second diffusion part 46 is set to about 1 mm, and the distance from the first diffusion part 34 to the third diffusion part 52 is set to 2 mm or more (preferably 3 mm or more). Yes.

(Video display method)
Next, a method for displaying an image in the rear projection display device including the transmission screen according to the present embodiment will be described with reference to FIGS.
First, image light is projected from the projector 12 shown in FIG. This image light is reflected by the reflecting plate 13 and the reflecting plate 14 and enters the back surface of the transmissive screen 20.

  Next, in the transmissive screen 20 shown in FIG. 2, the image light incident on the Fresnel lens array 30 is first weakly diffused by the first diffusion unit 34, passes through the base material 32, and enters each Fresnel lens 31. . The image light projected radially from the projector is refracted by the inclined surface of each Fresnel lens 31 and converted into substantially parallel light. Thereafter, the image light emitted from the Fresnel lens array 30 is incident on the lenticular lens array 40 that is closely arranged on the Fresnel lens array 30.

The image light incident on the lenticular lens array 40 is collected for each lenticular lens 41 that is a unit convex lens, and forms an image near the surface of the substrate 42 on the viewer side. In addition, since the light shielding layer 45 is formed in the non-condensing part of the image light by the lenticular lens 41, the image light is transmitted through the gap between the stripe-shaped light shielding layers 45. Then, the image light after image formation is diverged radially for each lenticular lens 41. In addition, the image light is strongly diffused in the process of passing through the second diffusion unit 46. Thereby, the rear projection type display apparatus can secure a wide viewing angle. Thereafter, the image light passes through the support substrate 50, is weakly diffused by the third diffusion unit 52, and is emitted from the lenticular lens array 40.
As described above, the image light is emitted from the transmission screen of the rear projection display device, and the image is displayed by reaching the observer.

As described above, in the transmissive screen 20 of the present embodiment, the image light is strongly diffused in the second diffusion unit 46. Here, since the second diffusing unit 46 is formed in the vicinity of the imaging position of the video light by the lenticular lens array 40, the luminance distribution of the video light is likely to occur. However, in the transmissive screen 20 of the present embodiment, the first diffusing unit 34 and the third diffusing unit 52 are disposed apart from the image light imaging position by the lenticular lens array 40. By diffusing the image light in these diffusion units, the luminance distribution of the image light can be averaged. Moreover, since the distance from the first diffusion unit 34 to the third diffusion unit 52 is set to 2 mm or more (preferably 3 mm or more), the luminance distribution of the image light can be averaged reliably.
In FIG. 2, the second diffusing portion 46 is described in contact with the light shielding layer 45, but is not necessarily limited thereto, and may be optically disposed in the vicinity of the image light imaging position. More desirably, it may be in the vicinity of the condensing position of the lenticular lens array 40.

As described above in detail, in the transmissive screen 20 according to the first embodiment, the Fresnel lens array 30 is formed in a film shape, and the first diffusion unit 34 diffuses video light on the light source side of the Fresnel lens array 30. Is formed in the vicinity of the imaging position on the viewer side of the lenticular lens array 40, and the second diffusion portion 46 for diffusing the image light is formed on the viewer side of the lenticular lens array 40. A support substrate 50 that secures rigidity is fixed, and a third diffusion unit 52 that diffuses image light is formed on the viewer side of the second diffusion unit 46 on the viewer side. It was.
According to this configuration, even when the luminance distribution of the image light is generated by diffusing the image light in the second diffusing unit 46 disposed in the vicinity of the image light image formation position, the image light is disposed away from the image formation position. By diffusing the image light in the first diffusion unit 34 and the third diffusion unit 52, the luminance distribution of the image light can be averaged. Therefore, scintillation of the video can be prevented.

(Second Embodiment)
Next, a transmission screen according to the second embodiment will be described with reference to FIG.
FIG. 3 is a plan sectional view of a transmission screen according to the second embodiment. In the transmissive screen 220 according to the second embodiment, the transparent member 48 is fixed to the observer side of the second diffusing unit 46, and the support substrate 50 that ensures the rigidity of the lenticular lens array 40 is provided on the observer side of the transparent member. The third diffusion part 52 is formed on the surface of the support substrate 50 on the viewer side. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.
In FIG. 3 as well, the second diffusing portion 46 is shown in contact with the light shielding layer 45, but this is not necessarily the case, and it may be optically disposed in the vicinity of the image light imaging position. More desirably, it may be in the vicinity of the condensing position of the lenticular lens array 40.

  In the transmissive screen 220 according to the second embodiment, the transparent member 48 is fixed to the observer side of the second diffusion unit 46. The transparent member 48 is made of a light transmissive material such as PET. In addition, since the self-supporting property (rigidity) of the lenticular lens array 40 is ensured by the support substrate 50, it is not necessary to form the transparent member 48 thick. Thereby, the lenticular lens array 40 of 2nd Embodiment is formed in the film form of thickness about 0.3-1.0 mm.

  The constituent material of the transparent member 48 is preferably matched with the constituent material (for example, PET) of the base material 42. In this regard, in the conventional transmission type screen, even if the lenticular lens array 40 is made of materials having different environmental characteristics such as expansion coefficient due to heat, moisture absorption, etc., the occurrence of warpage in the lenticular lens array 40 is caused by the Fresnel lens array 30. It was possible to hold down by the rigidity of. However, the film formation of the Fresnel lens array 30 makes it difficult to prevent the lenticular lens array 40 from warping. Therefore, warping of the lenticular lens array 40 can be prevented by configuring the base material 42 and the transparent member 48 of the lenticular lens array 40 with the same material or with materials having similar environmental characteristics.

  On the other hand, a support substrate 50 is disposed on the observer side of the transparent member 48. Similar to the support substrate of the first embodiment, the support substrate 50 is formed of a material such as MS, PMMA, or glass to a thickness of about 1 to 2 mm. The support substrate 50 is simply disposed adjacent to the transparent member 48 without being fixed. Accordingly, it is possible to prevent the warpage of the lenticular lens array 40 due to the difference in environmental characteristics between the transparent member 48 and the support substrate 50.

  A third diffusion portion 52 is formed on the viewer side of the support substrate 50. The third diffusing portion 52 is formed by subjecting the surface of the support substrate 50 on the viewer side to mat processing and roughening the surface. The third diffusion part 52 may be formed by attaching a diffusion film to the viewer side of the support substrate 50.

  In the transmissive screen 220 according to the second embodiment, as in the first embodiment, the first diffuser 34 of the Fresnel lens array 30 and the second diffuser 46 and the third diffuser 52 of the lenticular lens array 40 Three diffusion parts are formed. Among them, the second diffusion part 46 functions as a main diffusion part, and the first diffusion part 34 and the third diffusion part 52 function as secondary diffusion parts. The distance from the first diffusion part 34 to the second diffusion part 46 is set to about 1 mm, and the distance from the first diffusion part 34 to the third diffusion part 52 is set to 2 mm or more (preferably 3 mm or more). Yes.

  According to this configuration, even when the luminance distribution of the image light is generated by diffusing the image light in the second diffusing unit 46 disposed in the vicinity of the image light image formation position, the image light is disposed away from the image formation position. By diffusing the image light in the first diffusion unit 34 and the third diffusion unit 52, the luminance distribution of the image light can be averaged. Therefore, scintillation of the video can be prevented.

In the second embodiment described above, the transparent member 48 is fixed to the observer side of the second diffusing portion 46, the support substrate 50 is disposed on the observer side of the transparent member 48, and the surface of the support substrate 50 on the observer side. A third diffusion portion 52 was formed. In this case, since the distance from the 2nd spreading | diffusion part 46 to the 3rd spreading | diffusion part 52 becomes long, there exists a possibility that a blur may arise in an image | video.
Therefore, the third diffusion portion 52 may be provided on the light source side surface of the support substrate 50. In this case, by forming the transparent member 48 to a predetermined thickness, the distance between the second diffusing portion and the third diffusing portion can be set as appropriate, and blurring in the image can be prevented. it can.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and includes those in which various modifications are made to the above-described embodiment without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate.

  For example, in each of the embodiments described above, a lenticular lens array is used as the diffusing lens array. However, a microlens array in which a plurality of unit lenses are arranged in a matrix can also be used. Further, as the diffusing lens array, a cross wrench lens array in which the first cylindrical lens array and the second cylindrical lens array are arranged to intersect each other may be adopted. Furthermore, as the diffusing lens array, a prism lens array in which a plurality of unit lenses that reflect and diffuse video light may be used.

  In each of the above-described embodiments, the lenticular lens and the base material in the lenticular lens array are individually formed. However, they can be integrally formed of the same material. Similarly, the Fresnel lens and the base material in the Fresnel lens array can be integrally formed of the same material.

  Moreover, in each embodiment mentioned above, it was set as the structure which provides a 3rd spreading | diffusion part in the surface by the side of an observer or the surface by the side of a light source of a support substrate. In this case, the third diffusion portion can be easily formed, and the cost can be reduced. However, the third diffusion portion may be formed at an intermediate portion in the thickness direction of the support substrate. In this case, it is possible to appropriately set the distance between the second diffusion part and the third diffusion part while ensuring the rigidity of the lenticular lens array by the support substrate, and it is possible to prevent the occurrence of blurring in the image. it can.

It is side surface sectional drawing of a rear projection television. It is a plane sectional view of the transmission type screen concerning a 1st embodiment. It is a plane sectional view of a transmission type screen concerning a 2nd embodiment. It is a top sectional view of a transmission type screen concerning the prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Transmission type screen 30 ... Fresnel lens array 34 ... 1st diffuser part 40 ... Lenticular lens array 46 ... 2nd diffuser part 50 ... Supporting substrate 52 ... 3rd diffuser part

Claims (4)

A transmissive screen in which a Fresnel lens array that converts image light into substantially parallel light is disposed on a light source side, and a diffuser lens array that diverges the image light for each unit lens is disposed on an observer side,
The Fresnel lens array is formed in a film shape,
On the light source side of the Fresnel lens array, a first diffusion part for diffusing the image light is formed by matting and roughening the light source side surface of the substrate,
In the vicinity of the image forming position on the viewer side of the diffusing lens array, the second diffusing portion for diffusing the image light disperses the light diffusing material inside the resin adhesive having light transmittance or has a predetermined thickness. It is formed by attaching a diffusion film of
On the viewer side of the second diffusing section, the third diffusing section for diffusing the video light is matted to roughen the surface on the light source side of the support substrate that ensures the rigidity of the diffusing lens array. A transmissive screen characterized by being formed. The transmissive screen according to claim 1, wherein a transparent member is fixed to an observer side of the second diffusion part. The transmission screen according to claim 1 or 2 , wherein a distance between the first diffusion part and the third diffusion part is 2 mm or more. A rear projection display device comprising the transmissive screen according to any one of claims 1 to 3 .

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