JP4170369B2 - Transmission screen and projection display device - Google Patents

Description

  The present invention relates to a transmissive screen that eliminates the deterioration of display characteristics due to an ineffective light beam generated therein, and the present invention relates to a projection display device using the transmissive screen.

  Hereinafter, with reference to FIGS. 6 to 8, problems of a conventional transmission type screen using various types of Fresnel lens means such as a refractive Fresnel lens plate, a total reflection Fresnel lens plate, and a refractive total reflection Fresnel lens plate will be described.

  FIG. 6 is a view for explaining the structure and operation of a conventional refractive Fresnel lens plate, and shows the sectional shape of the refractive Fresnel lens plate having a refractive Fresnel surface formed on the incident side of the projected light beam.

  In FIG. 6, 110A is a refractive Fresnel lens plate (refractive Fresnel lens means), 111 is a refractive slope (refractive Fresnel surface), 112 is an invalid facet surface (refractive Fresnel surface), 115 is an exit surface, and n is a refractive Fresnel lens plate 110A. (Or the exit surface 115). Reference numeral 150 denotes a light beam projected onto the refractive Fresnel lens plate 110A, 152 denotes an ineffective light beam, and 153 denotes an effective light beam. The refractive Fresnel lens plate 110 </ b> A has a periodic structure composed of a combination of a refractive slope 111 and an invalid facet surface 112 adjacent to the refractive slope 111.

Next, the operation will be described.
The projected light beam 150 is incident on the normal line n of the refractive Fresnel lens plate 110A from an oblique direction, and a part thereof is refracted (optically acting) in the direction of the normal line n by the refractive inclined surface 111 to be refracted Fresnel lens plate 110A. Is emitted as an effective light beam 153 from the exit surface 115 of the light source.

  On the other hand, the remaining portion of the projected light beam 150 is refracted (optically affected) by the invalid facet surface 112 to become an invalid light beam 152. The ineffective light beam 152 is inclined from the direction of the normal line n, part of which is emitted from the exit surface 115 and another part is reflected by the exit surface 115. The reactive light beam 152 reflected by the exit surface 115 is then incident again on the refractive slope 111 or the invalid facet surface 112 constituting the refractive Fresnel lens plate 110A, and is refracted between the refractive slope 111 or the invalid facet surface 112 and the exit surface 115.・ Repeat repeatedly.

  Of these light beams, the effective light beam 153 is normal image light, and the invalid light beam 152 is a cause of generating a double image or a ghost image in which a bright spot or a line image is displayed in addition to the normal display position. It was.

  FIG. 7 is a view for explaining the structure and operation of a conventional total reflection Fresnel lens plate, and shows the cross-sectional shape of a total reflection Fresnel lens plate having a total reflection Fresnel surface formed on the incident side of a projected light beam.

  In FIG. 7, 110B is a total reflection Fresnel lens plate (total reflection Fresnel lens means), 113 is a total reflection slope (total reflection Fresnel surface), 114 is a transmission slope (total reflection Fresnel surface), 115 is an exit surface, and n is a total reflection surface. This is a normal line of the reflective Fresnel lens plate 110B (or the exit surface 115). Further, 150 is a light beam projected onto the total reflection Fresnel lens plate 110B, 151 is an effective light beam, and 152 is a "light beam" (ineffective light beam). The total reflection Fresnel lens plate 110 </ b> B is configured by a periodic structure including a combination of a total reflection slope 113 and a transmission slope 114 adjacent to the total reflection slope 113.

Next, the operation will be described.
The projected light beam 150 is incident on the normal line n of the total reflection Fresnel lens plate 110B from an oblique direction. A part of the projection light beam 150 is refracted (optically acted) by the transmission slope 114 and then the normal reflection slope 113 is directed to the normal line n. The light is reflected (optically actuated) and emitted as an effective light beam 151 from the emission surface 115 of the total reflection Fresnel lens plate 110B.

  On the other hand, the remaining portion of the projected light beam 150 is not reflected by the total reflection inclined surface 113 but becomes “that light beam” 152. The “light beam” 152 is inclined from the direction of the normal line n, part of which is emitted from the exit surface 115 and another part is reflected by the exit surface 115. The “light beam” 152 reflected by the exit surface 115 is then incident again on the total reflection slope 113 or transmission slope 114 constituting the total reflection Fresnel lens plate 110B, and the total reflection slope 113 or transmission slope 114 and the exit surface 115 Repeated refraction and reflection.

  Of the above light beams, the effective light beam 151 is normal image light, and “the light beam” 152 is a cause of generating a double image or a ghost image in which a bright spot or a line image is displayed in addition to the normal display position. It was.

  FIG. 8 is a diagram for explaining the structure and operation of a conventional refractive total reflection Fresnel lens plate. The refractive total reflection Fresnel lens plate in which both the refractive Fresnel surface and the total reflection Fresnel surface are formed on the incident side of the projected light beam. The structure is shown. 6 and 7 are the same or corresponding components. In FIG. 8, reference numeral 110C denotes a refractive total reflection Fresnel lens plate (refractive total reflection Fresnel lens means).

Next, the operation will be described.
The projected light beam 150 is incident on the normal line n of the refractive total reflection Fresnel lens plate 110C from an oblique direction. The light beam refracted (optical action) on the refractive slope 111 becomes an effective light beam 153 traveling in the direction of the normal line n. The light beam refracted (optical action) by the transmission slope 114 and reflected (optical action) by the total reflection slope 113 becomes an effective light beam 151 traveling in the direction of the normal line n.

  On the other hand, the projection light beam 150 refracted (optical action) by the invalid facet surface 112 and the projection light beam 150 refracted (optical action) by the transmission slope 114 and not totally reflected by the total reflection slope 113 are an invalid light beam (“it Luminous flux ") 152. The ineffective light beam 152 travels in a direction inclined from the normal line n, part of which is emitted from the exit surface 115 and another part is reflected by the exit surface 115. The reactive light beam 152 reflected by the exit surface 115 is then incident again on the refractive slope 111, the invalid facet surface 112, the total reflection slope 113, and the transmission slope 114 constituting the refractive total reflection Fresnel lens plate 110C. The surface 112, the total reflection slope 113, the transmission slope 114, and the exit surface 115 are repeatedly refracted and reflected.

  Among the above light beams, the effective light beams 151 and 153 are normal image light, and the invalid light beam 152 is a cause of generating a double image or a ghost image in which a bright spot or a line image is displayed in addition to the normal display position. It was.

  The conventional transmissive screen has horizontal and vertical viewing angles on the exit surface 115 side of the Fresnel lens plate 110A, total reflection Fresnel lens plate 110B, and refractive total reflection Fresnel lens plate 110C shown in FIGS. A lenticular lens plate for controlling the image and forming an image is disposed (not shown).

  Since the conventional transmissive screen is configured as described above, ineffective light beams that cause double images and ghost images can be avoided in principle, in addition to effective light beams that contribute to the display of regular projected images. In other words, there is a problem that the double image / ghost image is displayed superimposed on the regular projection image.

  The generation of double images and ghost images is an obstacle to displaying high-quality images, and it is therefore necessary to improve these reductions.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a high-quality transmissive screen capable of removing an ineffective luminous flux and displaying a normal projection image only with an effective luminous flux.

  Another object of the present invention is to provide a projection display device that can display a high-quality image by eliminating the generation of double images and ghost images.

The transmissive screen according to the present invention has a rotation target axis, and gives Fresnel lens means for applying the optical action of the Fresnel surface molded on the incident surface to the projected light beam to be emitted from the emission surface, and the optical of the Fresnel surface. From the stray light removing means having an opaque portion formed by a vertical periodic structure having a vertical periodicity or a vertical periodic structure that removes only light beams having different angles depending on the difference in mechanical action, and from the stray light removing means A condensing lens in which a stray light removing unit has unit lenses arranged in a vertical periodic structure on an incident surface of a first transmission substrate in an image display unit that scatters a light beam to form an image. An array means, a transparent portion provided in the vicinity of the condensing point of the unit lens, and an opaque portion provided in the vicinity of the condensing point of the unit lens are vertically arranged on the exit surface of the first transmission substrate. And it has a first stripe means alternately arranged in a linear periodic structure.

The transmission screen according to the present invention has a rotation target axis, and provides Fresnel lens means for applying the optical action of the Fresnel surface molded on the incident surface to the projected light beam and exiting from the exit surface, and the optical of the Fresnel surface The stray light removing means having an opaque portion formed by a linear periodic structure in the vertical direction or the vertical direction and the horizontal direction is removed, and the light flux from the stray light removing means is removed. Condensing lens array means in which stray light removing means has unit lenses arranged in a vertical periodic structure in the vertical direction on the incident surface of the first transmissive substrate, in a transmissive screen comprising an image display means for forming an image by scattering And a transparent portion provided near the condensing point of the unit lens and an opaque portion provided near the condensing point of the unit lens are intersected with the outgoing surface of the first transmission substrate with a linear periodic structure in the vertical direction. Since the ineffective beam generated in the vertical direction is removed by the stray light removing means, and the stray light removing means and the image forming display means are combined to deviate from the center of the transmission screen to the left and right. The ineffective light flux generated obliquely in the region can be removed, so that the double image and ghost image can be precisely removed to improve the display image quality.

An embodiment of the present invention will be described below. In addition, the same code | symbol in each drawing has shown the same or equivalent component.
Embodiment 1 FIG.
FIG. 1 is a view showing a vertical sectional structure of a transmission screen according to Embodiment 1 of the present invention, and FIG. 2 is a view showing a perspective structure of the transmission screen according to Embodiment 1 of the present invention.

  In FIG. 1, 10C is a refractive total reflection Fresnel lens plate (refractive total reflection Fresnel lens means), 20 is a stray light removing plate (stray light removing means), and 30 is an image forming display plate (image forming display means). The refracted total reflection Fresnel lens plate 10C, the stray light removing plate 20, and the imaging display plate 30 constitute a transmission screen. n is a normal line common to the refractive total reflection Fresnel lens plate 10 </ b> C, the stray light removing plate 20, and the imaging display plate 30. In FIG. 2, reference numeral 40 denotes a projection optical system that emits a projected light beam 50, and reference numeral 90 denotes an enlarged display image viewer.

Next, the operation will be described.
A part of the projected light beam 50 that is emitted from the projection optical system 40 and is inclined with respect to the normal line n and enters the refractive total reflection Fresnel lens plate 10C is refracted provided on the incident surface of the refractive total reflection Fresnel lens plate 10C. The effective light beam 53 is refracted by the slope 11 and parallel to the normal line n. Another part of the projected light beam 50 is refracted by the transmission slope 14 and then reflected by the total reflection slope 13 to become an effective light beam 51 parallel to the normal line n.

  The projection light beam 50 other than these is refracted by the invalid facet surface 12 adjacent to the refractive slope 11 or is refracted by the transmission slope 14 and is not reflected by the total reflection slope 13 but tilted with respect to the normal n ( “That light flux”) 52, both of which are incident on the exit surface 15.

  The stray light removing plate 20 includes a condensing lens array (condensing lens array means) 21 formed on the incident surface side of the transmission substrate (first transmission substrate) 22 and a black stripe formed on the output surface side of the transmission substrate 22. (First black stripe means) 23. As shown in FIG. 2, the condenser lens array 21 and the black stripe 23 typically include a lens array having periodicity in the vertical direction and a transparent / opaque lattice plate structure. In the black stripe 23, transparent portions 201 near the condensing point of each unit lens constituting the condensing lens array 21 and opaque portions 200 around the condensing point are periodically and alternately formed.

  In FIG. 1, effective light beams 51 and 53 deflected in a direction along the normal line n by the refractive total reflection Fresnel lens plate 10 </ b> C are incident on the condenser lens array 21, and then collected near the focal point of the unit lens of the condenser lens array 21. The light is transmitted, passes through the transparent portion 201, becomes an effective outgoing light beam 55, and enters the imaging display plate 30. For this reason, the center of each unit lens of the condensing lens array 21 and the center of the transparent portion 201 are arranged so as to substantially coincide with each other as shown in FIG.

  A lenticular lens (cylindrical lens array, lenticular lens means) 31 having periodicity in the horizontal direction is provided on the incident surface of the imaging display plate 30, and a transmission substrate ( A second transmissive substrate 32 is provided to hold the lenticular lens 31.

  The lenticular lens 31 has a function of diffusing incident light in the horizontal direction. In addition, scattering particles made of a known material are dispersed and held inside or near the surface of the transmissive substrate 32. The transmissive substrate 32 forms a projected image by acting as a diffusion plate. Therefore, the horizontal light distribution characteristic of the image light beam 80 emitted from the transmissive screen is determined from the refractive power of the lenticular lens 31 and the scattering characteristic of the transmissive substrate 32. The vertical light distribution characteristic of the image light beam 80 is determined from the refractive power of the condenser lens array 21 of the stray light removing plate 20 and the scattering characteristic of the transmission substrate 32.

  Since the effective light beams 51 and 53 are deflected in the direction along the normal line n by the refractive slope 11 and the total reflection slope 13, the image light beam 80 emitted from the transmission screen has good symmetry with respect to the normal line n. The light distribution characteristic is convenient for the viewer 90 who is located in front of the transmissive screen to view the image.

Next, the action of removing the ineffective light beam by the stray light removing plate 20 will be described.
The ineffective light beam 52 generated by the refracted total reflection Fresnel lens plate 10C enters the stray light removal plate 20 through the emission surface 15 while being inclined with respect to the normal line n. Alternatively, after the invalid light beam 52 is reflected as the reflected invalid light beam 54 on the exit surface 15, it is again applied by the refractive slope 11, the invalid facet surface 12, the total reflection slope 13, the transmission slope 14, etc. on the incident surface side of the refractive total reflection Fresnel lens plate 10C. The light beam is refracted and reflected, and a part of the light beam passes through the emission surface 15 and reenters the stray light removing plate 20 as an invalid light beam. According to a detailed ray tracing simulation, it has been found that most of the ineffective light beam upon re-incidence is a light beam that is largely inclined with respect to the normal line n.

  An invalid light beam (including an invalid light beam that re-enters) 52 that is inclined with respect to the normal line n and enters the stray light removal plate 20 is transmitted by the condensing lens array 21 and then absorbed by the opaque portion 200 of the black stripe 23. Therefore, the incidence on the imaging display panel 30 is prevented. Therefore, the generation of a double image or a ghost image due to the invalid light beam 52 is greatly improved.

  The opaque part 200 is configured by selective application of various known black paints, patterning, selective roughening of the exit side surface of the transmissive substrate 22, or a combination thereof.

  Further, the function of removing the ineffective light beam of the stray light removing plate 20 used in the present invention is realized by the condensing lens array 21 and the black stripe 23 having periodicity in the vertical direction, and therefore the refractive total reflection Fresnel lens plate 10C. When the axis of rotational symmetry is located on the left and right center line of the transmissive screen, it functions ideally in the cross section including this center line.

  Further, by making the condensing lens array 21 and the black stripe 23 have a concentric periodic structure with respect to the rotation center of the refractive total reflection Fresnel lens plate 10C, the stray light removing plate 20 functions more effectively. Can be made.

  Furthermore, ideally, the light blocking function of the stray light removing plate 20 is originally exhibited when the transmission substrate 22 and the condenser lens array 21 do not have a scattering function, and the scattering action for imaging is the transmission substrate 32. However, it is a common technique to arrange them in a shared manner. However, a scattering function is added to the material of the transmissive substrate 22 and the condenser lens array 21 which are constituent elements of the stray light removing plate 20 so that the transmissive screen is displayed. It is also possible to control the light distribution characteristics and the imaging action of the incident light.

  For example, in order to prevent deterioration of the projected image due to scintillation occurring in the image light beam 80, minute particles are intentionally mixed in the material of the transmission substrate 22 and the condenser lens array 21 to give some scattering characteristics, In some cases, it is effective to disperse and arrange the scattering functions in the direction of the normal line n of the transmission type screen in combination with the scattering characteristics of the transmission substrate 32 having a long distance. Therefore, whether or not to provide the scattering function to the components of the stray light removing plate 20 depends on the system design of the projection display device.

  Further, when the lens array 21, the transmissive substrate 22, and the black stripe 23 constituting the stray light removing plate 20 are thin and unsuitable for holding, the transmissive substrate (holding transmissive substrate) as shown by the dotted line in FIG. 24 may be configured to hold them.

  Further, the inventors of the present application, as shown in FIG. 2, have a stray light removing plate 20 configured by linear black stripes 23 having a periodicity in the vertical direction as well as a linear condenser lens array 21 having a periodicity in the vertical direction. Was combined with a refractive total reflection Fresnel lens plate 10C having a rotational symmetry axis on the center line of the transmission screen and in the vicinity of the lower portion of the transmission screen, and the projected image was observed. As a result, it was confirmed that the double image / ghost image superimposed on the display image was reduced in a corresponding region in the transmissive screen surface with the vertical portion passing through the center of the image as the center.

  This means that the stray light removal plate 20 that should ideally have a concentric structure with respect to the center of the refractive total reflection Fresnel lens plate 10C is composed of a condensing lens array having a linear stripe structure and a black stripe. This means that a certain image quality improvement effect can be obtained. By substituting this stray light removing plate, it becomes possible to provide a transmissive screen that can relieve the restrictions on manufacturing the stray light removing plate and display a good image at low cost.

  As described above, according to the first embodiment, the refractive / reflective total reflection Fresnel lens that emits the refraction / reflection optical action of the refractive total reflection Fresnel surface molded on the incident surface to the projection light beam 50 and exits from the output surface 15. The plate 10C, a condensing lens array 21 in which unit lenses are arranged in a vertical structure on the incident surface of the transmissive substrate 22, a transparent portion 201 provided in the vicinity of the condensing point of the unit lenses, and condensing of the unit lenses A stray light removing plate 20 composed of black stripes 23 in which opaque portions 200 provided around a point are alternately arranged in a vertical structure on the emission surface of the transmissive substrate 22, and the light flux is scattered by its scattering characteristics. Since the image forming display plate 30 is formed of the lenticular lens 31 in which unit lenses are arranged in a horizontal periodic structure on the incident surface of the transmission substrate 32, the ineffective light beams 52 and 5 are provided. Was removed, there is an advantage that it provides a high-quality transmissive screen that can display a projection image of the normal only in the effective light beam 51 and 53.

  Further, according to the first embodiment, the refracted total reflection Fresnel lens plate 10 </ b> C is refracted by the refractive slope 11 and refracted by the transmission slope 14 in a direction substantially parallel to the normal line n of the exit surface 15. Since the refracted total reflection Fresnel lens plate 10C is reflected by the total reflection inclined surface 13 in a direction substantially parallel to the normal line n of the exit surface 15, the light beam is symmetrical with respect to the normal line n direction of the transmission screen. A display image having a light distribution characteristic can be formed, and an effect can be obtained that an image can be displayed under optimum conditions for the viewer 90 located at the center of the transmission screen.

  Furthermore, according to the first embodiment, since the stray light removing plate 20 includes the transmission substrate 24 for holding the transmission substrate 22, the condenser lens array 21, and the black stripe 23, the transmission substrate 22, the collector Even when the layers of the optical lens array 21 and the black stripe 23 are thin, the effect that the stray light removing plate 20 can be configured is obtained.

  Further, according to the first embodiment, the stray light removing plate 20 includes the condensing lens array and the first black stripe molded with a concentric periodic structure with respect to the rotation center of the Fresnel lens plate 10C. An effect is obtained that the function of removing the ineffective light beam of the stray light removing plate 20 can be functioned more effectively.

  Furthermore, according to the first embodiment, since the stray light removal plate 20 includes the condenser lens array and the first black stripe molded with a linear periodic structure, there are restrictions in manufacturing the stray light removal plate 20. The effect of relieving greatly and displaying a good image at low cost is obtained.

  Furthermore, according to the first embodiment, the stray light removing plate 20 is provided with the transmission substrate 22 with the scattering characteristics or the condensing lens array 21 with the scattering characteristics, so that the projection by the scintillation generated in the image light beam 80 is performed. An effect of preventing image deterioration can be obtained.

  Further, according to the first embodiment, since the projection optical system 40 for projecting the projection light beam 50 onto the transmissive screen and displaying the image on the transmissive screen is provided, the generation of the double image / ghost image is provided. It is possible to provide a projection display device that can display a high-quality image by removing the image.

Embodiment 2. FIG.
In the second embodiment, a method that can reduce the double image and the ghost image in a wider area in the projected image will be described.

FIG. 3 is a view showing the structure of a transmission screen according to Embodiment 2 of the present invention. In FIG. 3, 33 is a transmissive substrate (third transmissive substrate), and 34 is a black stripe (second black stripe means).
In FIG. 3, the imaging display plate 30 has a function of the stray light removing plate 20 for removing the horizontal component of the ineffective light beam. For this purpose, a black stripe 34 having a periodicity in the horizontal direction and a transmission substrate 33 are arranged between the lenticular lens 31 having a periodicity in the horizontal direction and the transmission substrate 32. Since other configurations are the same as those in FIGS. 1 and 2, description of the configuration is omitted.

  FIG. 3B shows an enlarged view of the structure of the image forming display plate 30 in FIG. In order to form a projection image as in the first embodiment of FIG. 2, the transmissive substrate 32 has scattering particles made of a known material dispersedly held inside or near the surface of the transmissive substrate 32 so as to have diffusion characteristics. Yes. The lenticular lens 31 is a cylindrical lens array that extends vertically and has periodicity in the horizontal direction.

  Further, the black stripe 34 has a horizontal periodic structure in which the transparent portion 301 is aligned with the center of each unit lens of the lenticular lens 31 and the opaque portion 300 is removed from the lens center. Further, the opaque portion 300 is configured by selective application of various known black paints, patterning, selective roughening of the exit side surface of the transmissive substrate 33, or a combination thereof. The black stripe 34 and the lenticular lens 31 are held so as to maintain a predetermined distance across the transmission substrate 33, and the black stripe 34 side is attached to the transmission substrate 32 by a method such as adhesion.

  As described above, by forming the image forming display plate 30, the image forming display plate 30 can be provided with a function of removing the invalid luminous flux in the horizontal direction on the same principle as the stray light removing plate 20 of FIG. As a result, when the refractive total reflection Fresnel lens plate 10C whose rotational symmetry axis is on the transmission screen center line and near the lower portion of the transmission screen is used, it is vertically moved near the horizontal center of the transmission screen. The generated ineffective light flux is removed by the stray light removing plate 20 and the combination of the stray light removing plate 20 and the imaging display plate 30 can remove the ineffective light flux generated obliquely in the region left and right off the center of the transmission screen. 1, compared with the case of FIG. 2, a double image and a ghost image can be removed more precisely.

  As described above, according to the second embodiment, the transparent portion 301 provided between the transmission substrate 32 and the lenticular lens 31 in the vicinity of the condensing point of the unit lens of the lenticular lens 31 and the collection of unit lenses. Since the imaging display plate 30 is provided with the black stripes 34 in which the opaque portions 300 provided around the light spots are alternately arranged on the emission surface of the transmission substrate 33 in a horizontal periodic structure, The direction component and the horizontal direction component can be removed, and the effect that the double image / ghost image can be removed more precisely is obtained.

Embodiment 3 FIG.
In the third embodiment, as in the second embodiment, a description will be given of a configuration modification example of the transmission screen that can remove both the vertical component and the horizontal component of the ineffective light beam.

  FIG. 4 is a diagram showing the structure of a transmission screen according to Embodiment 3 of the present invention. 4A, reference numeral 10C denotes a refractive total reflection Fresnel lens plate similar to that shown in FIG. 1, reference numeral 20 denotes a stray light removal plate disposed on the exit surface 15 side of the refractive total reflection Fresnel lens plate 10C, and reference numeral 26 denotes a stray light removal plate 20. The transparent portion, 25 is a louver-like opaque portion of the stray light removing plate 20, and 55 is an effective outgoing light beam of the stray light removing plate 20. The configuration of the image forming display plate 30 is the same as that shown in FIG.

  Further, FIG. 4B shows an enlarged perspective view of the stray light removing plate 20 and the refractive total reflection Fresnel lens plate 10C as viewed from the effective outgoing light beam 55 side. In this enlarged perspective view, reference numeral 25H denotes horizontal louver-like opaque portions, which are periodically arranged with the transparent portions 26 interposed therebetween in the vertical direction. Reference numeral 25V denotes vertical louver-like opaque portions, which are periodically arranged with the transparent portions 26 sandwiched in the horizontal direction.

Next, the operation of the transmission screen of FIG. 4 will be described.
As in the case of FIG. 1, the projection light beam 50 has effective light beams 53 and 51 traveling in the direction of the normal line n of the transmission screen by the refraction action of the refraction slope 11 and the action of the transmission slope 14 and the total reflection slope 13. Become. The effective light beams 53 and 51 pass through the transparent portion 26 to become an effective output light beam 55 and enter the image forming display plate 30, diffused in the horizontal direction by the lenticular lens 31, and then on the transmissive substrate 32 having scattering properties. A projected image is formed. The light distribution characteristic in the horizontal direction of the image light beam 80 is determined by the horizontal diffusion characteristic of the lenticular lens 31 and the scattering characteristic of the transmission substrate 32. Further, the light distribution characteristic in the vertical direction is determined by the scattering characteristic of the transmission substrate 32.

  A dotted line arrow denoted by reference numeral 52 is an ineffective light beam transmitted through the invalid facet surface 12 of the refractive total reflection Fresnel lens plate 10C, or an ineffective light beam transmitted through the transmission slope 14 and not reflected by the total reflection slope 13. . The ineffective light beam 52 is absorbed by the louver-like opaque portion 25 configured along the direction of the normal line n, or reflected by the interface 15 between the refractive total reflection Fresnel lens plate 10C and the stray light removing plate 20. A reflected invalid light beam 54 is obtained. After that, the reflected invalid light beam 54 at the interface 15 is refracted / reflected by the refractive slope 11, the invalid facet surface 12, the total reflection slope 13, and the transmission slope 14 on the incident side of the refractive total reflection Fresnel lens plate 10 </ b> C. It is incident again and most of it is absorbed by the louver-like opaque portion 52.

  The reflected invalid light beam 54 due to the interface 15 is almost generated when the stray light removing plate 20 is integrally formed on the back surface (outgoing surface) side of the refracted total reflection Fresnel lens plate 10C or when both are bonded with an adhesive or the like. It is not necessary to consider because it does not. The stray light removing plate 20 uses, for example, an acrylic material to mold a lattice-like groove with a mold in which a projection row corresponding to the louver-like opaque portion 25 is formed, and injects ink or ink having absorption into the groove portion. Can be formed.

  When ink or ink is injected, it is necessary to appropriately remove the dirt component remaining on the surface of the stray light removing plate 20 so as not to disturb the transmission characteristics of the transparent portion 26. The stray light removing plate 20 created in this way is bonded to a refractive total reflection Fresnel lens plate 10C made of, for example, an acrylic material with an adhesive having a refractive index similar to that of acrylic, and both are integrally molded and reflected. Generation of the ineffective light beam 54 can be minimized. Of course, there is no problem even if the stray light removing plate 20 is directly integrally formed on the back side of the refractive total reflection Fresnel lens plate 10C and then injected by injecting ink or ink.

  4A shows a vertical sectional view of the transmissive screen, but the projected light beam 50 also has an oblique component or a horizontal component, and the horizontal component of the invalid light beam generated in this case is the vertical direction. The louver-like opaque portion 25V is mainly absorbed. The vertical component of the ineffective light beam is mainly absorbed by the horizontal louver-like opaque portion 25H.

  Further, the louver-like opaque portions 25, 25V, 25H may be shaped so that the width gradually changes along the direction of the normal line n in consideration of the ease of mold molding and the ease of ink / ink injection. good. In this case, in FIG. 4A showing a cross-sectional view of the transmission screen, the louver-like opaque portion 25 has a gentle trapezoidal shape whose width changes along the normal line n (not shown).

  As described above, according to the third embodiment, the transparent portion 26 that transmits the light beam, the horizontal direction louver-like opaque portion 25H that is arranged with the transparent portion 26 sandwiched between the vertical structures in the vertical direction, and the transparent portion 26, respectively. Since the stray light removing plate 20 is composed of the vertical louver-like opaque portions 25V arranged with the periodic structures in the horizontal direction, the vertical component and the horizontal component of the ineffective light beam 52 can be removed. Thus, the effect that the double image / ghost image can be removed more precisely is obtained.

  Further, according to the third embodiment, the stray light removing plate 20 forms the cross-sectional shapes of the louver-like opaque portions 25H and 25V in a trapezoidal shape whose width varies along the normal line n of the exit surface 15 of the Fresnel lens plate 10C. As a result, it is possible to obtain an effect that the stray light removing plate 20 can be easily molded and black / ink injection corresponding to the louver-like opaque portion can be easily performed.

  Further, according to the third embodiment, since the stray light removing plate 20 is integrally formed on the exit surface 15 of the Fresnel lens plate 10C, the generation of the reflected invalid light beam generated on the exit surface of the Fresnel lens plate 10C is minimized. The effect that it can suppress to the limit is acquired.

Embodiment 4 FIG.
FIG. 5 shows a configuration example in which a louver element and a lenticular lens with a black stripe can be combined to remove both the vertical and horizontal components of the ineffective light beam.

FIG. 5 is a view showing the structure of a transmission screen according to Embodiment 4 of the present invention.
In FIG. 5, reference numeral 20 denotes a stray light removing plate, which is composed of a louver-like opaque portion 25 and a transparent portion 26. As shown in FIG. 5B, the louver-like opaque part 25 is composed only of horizontal louver-like opaque parts 25H arranged periodically in the vertical direction. Further, the imaging display plate 30 is configured by laminating a lenticular lens 31, a transmission substrate 33, a black stripe 34, and a transmission substrate 32 in this order from the incident side of the effective emitted light beam 55.

  As shown in the enlarged drawing of FIG. 5C, the black stripe 34 is composed of a stripe-shaped opaque portion 300 and a transparent portion 301 that are periodically arranged in the horizontal direction, and the central portion in the horizontal direction of the transparent portion 301 is a lenticular. The lens 31 is arranged in alignment with the center of each unit lens. In addition, the transmissive substrate 33 sets and holds a distance between the lenticular lens 31 and the black stripe 34. The configuration of the refractive total reflection Fresnel lens plate 10C is the same as that in FIG.

Next, the operation of the transmission screen of FIG. 5 will be described.
As in the case of FIG. 1, the projected light beam 50 has effective light beams 53 and 51 that travel in the direction of the normal line n of the transmission screen by the refraction action of the refraction slope 11 and the action of the transmission slope 14 and the total reflection slope 13. It becomes. The effective light beams 53 and 51 are transmitted through the transparent portion 26 to become an effective output light beam 55 and enter the imaging display plate 30, diffused in the horizontal direction by the lenticular lens 31, and then onto the transmissive substrate 32 having scattering properties. A projected image is formed. The light distribution characteristic in the horizontal direction of the image light beam 80 is determined by the horizontal diffusion characteristic of the lenticular lens 31 and the scattering characteristic of the transmission substrate 32. Further, the light distribution characteristic in the vertical direction is determined by the scattering characteristic of the transmission substrate 32.

  A dotted line arrow denoted by reference numeral 52 is an ineffective light beam transmitted through the invalid facet surface 12 of the refractive total reflection Fresnel lens plate 10C, or an ineffective light beam transmitted through the transmission slope 14 and not reflected by the total reflection slope 13. . The ineffective light beam 52 is absorbed by the louver-like opaque portion 25 configured along the direction of the normal line n, or reflected by the interface 15 between the refractive total reflection Fresnel lens plate 10C and the stray light removing plate 20. The reactive light beam 54 is obtained. The reflected invalid light beam 54 is then refracted / reflected by the refractive slope 11, the invalid facet surface 12, the total reflection slope 13, and the transmission slope 14 on the incident side of the refractive total reflection Fresnel lens plate 10C, and is incident on the interface 15 again. Most of the louver-like opaque portion 52 is absorbed.

  The reflection invalid light beam 54 due to the interface 15 is hardly generated when the stray light removing plate 20 is integrally formed on the back surface side of the refractive total reflection Fresnel lens plate 10C or the both are bonded with an adhesive or the like. There is no need. The stray light removing plate 20 is formed by, for example, using an acrylic material, molding a lattice-like groove with a mold in which a projection row corresponding to the louver-like opaque portion 25 is formed, and injecting ink or ink having absorption into the groove portion. Can be formed. The stain component remaining on the surface of the stray light removing plate at the time of injecting the black ink or the ink needs to be processed so as not to disturb the transmission characteristics of the transparent portion 26 by appropriately wiping off.

  The stray light removing plate 20 created in this way is bonded to a refractive total reflection Fresnel lens plate 10C made of, for example, an acrylic material with an adhesive having a refractive index similar to that of the refractive total reflection Fresnel lens plate 10C. Of course, there is no problem even if the stray light removing plate 20 is directly integrally formed on the back side of the refractive total reflection Fresnel lens plate 10C and then injected by injecting ink or ink.

  The louver-like opaque portions 25 and 25H may have a shape in which the width gradually changes along the direction of the normal line n in consideration of the ease of molding and the ease of ink / ink injection. In this case, in FIG. 5A showing a cross-sectional view, the louver-like opaque portion 25 has a gentle trapezoidal shape whose width changes along the normal line n (not shown).

  Although FIG. 5A shows a vertical sectional view of the transmission screen, the projected light beam 50 also has an oblique component or a horizontal component, and the horizontal component of the invalid light beam generated in this case is mainly used. Absorption is removed by the action of the lenticular lens 31 in the imaging display plate 30 and the opaque portion 300 of the black stripe 34 (see FIG. 5C).

  Further, the lenticular lens 31 and the black stripe 34 are arranged so as to have periodicity in the horizontal direction, and the condenser lens array 21 and the black stripe 23 in FIG. The absorption principle is the same.

  Further, the vertical component of the ineffective luminous flux is mainly absorbed by the horizontal louver-like opaque portion 25H (see FIG. 5C).

  As described above, according to the fourth embodiment, the stray light removing plate 20 includes the transparent portion 26 that transmits the light flux and the horizontal louver-like opaque portion 25H that is arranged with the transparent portion sandwiched between the vertical structures in the vertical direction. The transparent part 301 provided near the condensing point of the unit lens of the lenticular lens 31 and the opaque part 300 provided near the condensing point of the unit lens between the transmission substrate 32 and the lenticular lens 31. Since the imaging display plate 30 is provided with the black stripes 34 alternately arranged in a horizontal periodic structure on the emission surface of the transmission substrate 33, the vertical and horizontal components of the ineffective light beam 52 can be removed. Thus, the effect that the double image / ghost image can be removed more precisely is obtained.

  Further, according to the fourth embodiment, the stray light removing plate 20 forms the cross-sectional shape of the louver-like opaque portion 25H in a trapezoidal shape whose width varies along the normal line n of the exit surface 15 of the Fresnel lens plate 10C. As a result, it is possible to obtain an effect that the stray light removing plate 20 can be easily molded and ink / ink can be easily injected corresponding to the louver-like opaque portion.

  Further, according to the fourth embodiment, since the stray light removing plate 20 is integrally formed with the exit surface 15 of the Fresnel lens plate 10C, the generation of the reflected invalid light beam generated on the exit surface of the Fresnel lens plate 10C is minimized. The effect that it can suppress to the limit is acquired.

  In each of the embodiments shown in FIGS. 1 to 5, the configuration and operation of the transmissive screen in combination with the refractive total reflection Fresnel lens plate 10C have been described. However, the refracted total reflection Fresnel lens plate 10C shown in FIGS. 1 to 5 may be applied to a transmission screen in which the following Fresnel lens plates (1) to (3) are replaced, and the same effect can be obtained.

(1) A transmissive screen in which a refractive Fresnel surface having a periodic structure consisting of a refractive slope and an ineffective facet surface is replaced with a refractive Fresnel lens plate (FIG. 6) formed on the incident surface side.

(2) A transmissive screen in which a total reflection Fresnel surface having a periodic structure composed of a total reflection slope and a transmission slope is replaced with a total reflection Fresnel lens plate (FIG. 7) formed on the incident surface side.

(3) Since the refractive total reflection Fresnel lens plate has a concentric structure, in order to increase the transmission efficiency in a portion with a small radius, it consists of a refractive slope and an ineffective facet surface with respect to the total reflection Fresnel part consisting of the total reflection slope and the transmission slope. Hybrid that obtains high transmission efficiency only in the total reflection Fresnel part in the part with a large radius, and the ratio of the total reflection Fresnel part is increased in the part with a large radius to increase the transmission efficiency gradually. A transmissive screen replaced with a refractive total internal reflection Fresnel lens plate.

It is a figure which shows the up-down direction cross-section of the transmission type screen by Embodiment 1 of this invention. It is a figure which shows the perspective structure of the transmission type screen by Embodiment 1 of this invention. It is a figure which shows the structure of the transmission type screen by Embodiment 2 of this invention. It is a figure which shows the structure of the transmission type screen by Embodiment 3 of this invention. It is a figure which shows the structure of the transmission type screen by Embodiment 4 of this invention. It is a figure for demonstrating the structure and operation | movement of the conventional refractive Fresnel lens plate. It is a figure for demonstrating the structure and operation | movement of the conventional total reflection Fresnel lens board. It is a figure for demonstrating the structure and operation | movement of the conventional refractive total reflection Fresnel lens plate.

Explanation of symbols

  10C refractive total reflection Fresnel lens plate (refractive total reflection Fresnel lens means), 11 refractive slope, 12 invalid facet surface, 13 total reflection slope, 14 transmission slope, 15 exit surface, 20 stray light removal plate (stray light removal means), 21 Optical lens array (condenser lens array means), 22 transmissive substrate (first transmissive substrate), 23 black stripe (first black stripe means), 24 transmissive substrate (holding transmissive substrate), 25 louver-like opaque portion, 25H horizontal Directional louver-like opaque portion, 25V Vertical louver-like opaque portion, 26, 201, 301 Transparent portion, 30 Imaging display plate (imaging display means), 31 Lenticular lens (lenticular lens means), 32 Transmission substrate (second transmission) Substrate), 33 transmission substrate (third transmission substrate), 34 black stripe (second black strap) 40 projection optical system, 50 projection beam, 51, 53 effective beam, 52 invalid beam, 54 reflected beam, 55 effective beam, 80 image beam, 90 viewer, 200, 300 opaque part, n normal .

Claims (9)

Fresnel lens means that has an axis of rotation and gives the optical action of the Fresnel surface molded on the entrance surface to the projected light beam and exits from the exit surface, and has a different angle depending on the difference in optical action of the Fresnel surface. The stray light removing means having an opaque portion formed by a linear periodic structure in the vertical direction or the vertical direction and the horizontal direction , and the light flux from the stray light removing means is scattered to form an image. In a transmissive screen provided with image display means,
The stray light removal means
Condensing lens array means in which unit lenses are arranged in a vertical periodic structure in the vertical direction on the incident surface of the first transmission substrate;
A transparent portion provided in the vicinity of the condensing point of the unit lens and an opaque portion provided in the vicinity of the condensing point of the unit lens have a linear periodic structure in the vertical direction on the emission surface of the first transmission substrate. A transmissive screen comprising first stripe means arranged alternately. The stray light removal means
2. The transmissive screen according to claim 1, further comprising a transmissive substrate for holding the first transmissive substrate, the condenser lens array means, and the first stripe means. The imaging display means
2. A transmissive screen according to claim 1, wherein said lenticular lens means comprises unit lenses arranged in a horizontal periodic structure on an incident surface of a second transmissive substrate that scatters a light beam by the scattering characteristics. Fresnel lens means that has an axis of rotation and gives the optical action of the Fresnel surface molded on the entrance surface to the projected light beam and exits from the exit surface, and has a different angle depending on the difference in optical action of the Fresnel surface. Stray light removing means having an opaque portion formed by a vertical periodic structure in the vertical direction and / or horizontal direction, and an image display means for forming an image by scattering the light flux from the stray light removing means In a transmissive screen with
The imaging display means
A transmissive screen comprising lenticular lens means in which unit lenses are arranged in a horizontal periodic structure on an incident surface of a second transmissive substrate that scatters a light beam by the scattering characteristics. The imaging display means
Between the second transmissive substrate and the lenticular lens means, a transparent part provided near the condensing point of the unit lens of the lenticular lens means and an opaque part provided around the condensing point of the unit lens are provided. 5. The transmission type screen according to claim 3, further comprising second stripe means arranged alternately in a horizontal periodic structure on an emission surface of the three transmission substrate. The stray light removal means
A transparent part that transmits the luminous flux;
It is composed of a horizontal louver-like opaque part arranged with the transparent part sandwiched between vertical periodic structures, respectively.
The imaging display means
Between the second transmissive substrate and the lenticular lens means, a transparent part provided near the condensing point of the unit lens of the lenticular lens means and an opaque part provided around the condensing point of the unit lens are provided. 5. The transmissive screen according to claim 4, further comprising second stripe means arranged alternately in a horizontal periodic structure on an output surface of the three transmissive substrate. The stray light removal means
7. The transmission screen according to claim 6, wherein the cross-sectional shape of the louver-like opaque part is formed in a trapezoidal shape whose width varies along the normal line of the exit surface of the Fresnel lens means. The stray light removal means
7. A transmission type screen according to claim 6, wherein said transmission type screen is formed integrally with the exit surface of the Fresnel lens means. The transmissive screen according to any one of claims 1 to 8,
A projection display apparatus, comprising: a projection optical system that projects a light beam onto the transmission screen and displays an image on the transmission screen.

Images