JP4103734B2 - Video display device - Google Patents

Description

  The present invention relates to an image display device that enlarges and projects an image of an image generation source and displays the image on a rear projection screen, a transmissive screen and a Fresnel lens sheet used in the image display device, and a manufacturing method thereof.

  Image display devices that use a projection lens, etc., to enlarge the image displayed on a projection cathode-ray tube or a liquid crystal display device as a compact image source and project it onto a rear projection screen have recently seen remarkable improvements in image quality. It is spreading for use.

  In such an image display device, the depth of the image display device is reduced by using a reflection mirror that reflects an enlarged image from the projection lens and guides it to the rear projection screen. As a rear projection screen used for this, a Fresnel lens sheet for converting an enlarged projection image into substantially parallel light or light slightly inward, and a lenticular lens sheet for diffusing image light in the horizontal direction of the screen are usually used. For example, a configuration described in Patent Document 1 below is known as a rear projection screen for coping with further thinning of the image display device.

WO / 02/27399

  The problem of the present invention will be described with reference to FIGS. If the image display device has the same screen size, the thinner the depth, the more advantageous in terms of weight, cost, and installation space. A reflection mirror 54 is provided to reduce the depth of the video display device. As a means for further reducing the depth, there is a method of widening the projection lens 52. However, there is a limit to widening the angle of the lens. For example, when the aspect ratio is 16: 9 and the diagonal is 65 inches, if the projection distance is 700 mm or less, the image generation source 51 and the projection lens 52 interfere with the projection light. A shadow is formed on the rear projection screen 53. Therefore, if it is attempted to reduce the thickness only by widening the projection lens 52, as shown in FIG. 13, when the aspect ratio is 16: 9 and the diagonal is 65 inches, the depth of the optical system is 400 mm (the depth of the image display device). 450 mm) is the limit. In FIG. 13, the optical axis center of the projection lens 52 and the center of the rear projection screen 53 coincide with each other and the optical axis and the screen are set to be vertical, but the optical axis center of the projection lens 52 is set to the lower end of the rear projection screen 53. By setting it in the vicinity, the image generation source 51 and the projection lens 52 do not interfere with the projection light even when the projection distance is 700 mm or less. 14 is a screen size having an aspect ratio of 16: 9 and a diagonal size of 65 inches as in FIG. 13, but the center of the optical axis of the projection lens 52 coincides with the lower end of the rear projection screen 53 and the projection distance is 500 mm. In this case, the depth of the optical system can be reduced to 300 mm (the depth of the image display device is 350 mm).

  As described above, by reducing the projection distance of the projection lens 52 and setting the center of the optical axis of the projection lens 52 in the vicinity of the lower end of the rear projection screen 53, the video display device can be made thinner. However, in this case, the following new problem occurs.

  In FIG. 14, the screen size is 65 inches diagonal with an aspect ratio of 16: 9. Therefore, if the center of the optical axis of the projection lens 52 is the center of the lower end of the rear projection screen 53, the left and right sides of the rear projection screen 53 from the projection lens 52. The screen incident angle of the image light incident on the upper end is 65.2 degrees. FIG. 15 is a diagram showing the relationship between the incident angle of light on the screen of a general exit surface Fresnel lens and the reflection loss. From the figure, it is understood that the reflection loss of the screen is as large as 36% when the light incident angle is 65.2 degrees. If the video display device is further reduced in thickness, this loss increases rapidly, resulting in a problem that the video display device becomes darker at the upper left and right ends of the screen.

  Further, in Patent Document 1, as a rear projection screen corresponding to a reduction in the thickness of an image display device, a refractive prism and a total reflection prism are alternately provided on a light incident surface of a Fresnel lens, and a light emitting surface is planar. It is disclosed that. However, since the configuration described in Patent Document 1 has a configuration in which a refractive prism is provided on the light incident surface of the Fresnel lens, the efficiency is lowered, and a mid-range image (a donut-shaped range on the screen) that is particularly important as an image. There is a problem that becomes darker.

  The present invention has been made in view of the problems as described above, and the object thereof is suitable for shortening the depth of a video display device. Moreover, even when the depth is shortened, the image quality is high. Another object of the present invention is to provide a technique suitable for obtaining an image (in which brightness reduction is suppressed).

  In order to achieve the above object, according to the present invention, the incident angle of the projected image projected from the optical component on the Fresnel lens sheet is at least approximately 40 degrees on the image generation source side of the Fresnel lens sheet constituting the rear projection screen. In the above-described range, a total reflection prism portion that gives incident light to a predetermined incident surface exit angle by the total reflection phenomenon after the first refraction phenomenon is provided in the above range, and the second view is provided on the image viewing side of the Fresnel lens sheet. A refracting prism portion that emits light as an outgoing light beam having a predetermined outgoing angle by a refraction phenomenon is provided.

  Further, in the present invention, the prism angle of the refractive prism portion provided on the image viewing side of the Fresnel lens sheet constituting the rear projection screen is determined from the optical component in the range where the image generation source side of the Fresnel lens sheet is a flat plate. The projected image is increased as the incident angle of the projected image on the Fresnel lens sheet increases, but the projected image is reduced from the position where it passes through the total reflection prism portion provided on the image generation source side.

  Further, in the present invention, a predetermined incident surface exit angle obtained by the first refraction phenomenon and the total reflection phenomenon at the starting point of the total reflection prism portion provided on the image generation source side of the Fresnel lens sheet constituting the rear projection screen. Similarly, the predetermined incident surface exit angle obtained by the third refraction phenomenon in the portion where there is no total reflection prism portion adjacent to the start point of the total reflection prism portion of the Fresnel lens sheet is made substantially equal.

  Further, in the present invention, the total reflection surface of the total reflection prism portion provided on the image generation source side of the Fresnel lens sheet constituting the rear projection screen is concave on the image generation source side.

  In the present invention, the refractive index of the material of the total reflection prism portion provided on the image generation source side of the Fresnel lens sheet constituting the rear projection screen is set to the refractive index of the material of the base material constituting the Fresnel lens sheet. Compared to larger.

  Further, in the present invention, the inclination of the incident surface of the total reflection prism portion provided on the image generation source side of the Fresnel lens sheet constituting the rear projection screen is set in the same direction as the total reflection surface of the total reflection prism portion. .

  Further, in the method for producing a Fresnel lens sheet according to the present invention, after forming a refractive prism portion on the image viewing side by heat compression molding a transparent base material such as a copolymer of polymethyl methacrylate or methyl methacrylate-styrene. The total reflection type prism portion is formed of an ultraviolet curable resin on the opposite side. Alternatively, a transparent base material on which a transparent ultraviolet curable resin layer having a total reflection prism portion is formed on the surface opposite to the surface on which the refractive prism portion is formed may be bonded and fixed with an adhesive layer.

  According to the present invention, the video display device can be thinned. In addition, even when the video display device is thinned, it is possible to obtain a video with high image quality (particularly, a reduction in brightness).

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a partial sectional perspective view of a video display device according to the present invention. The image generation source 1 is composed of a projection type cathode ray tube, a reflection type or transmission type liquid crystal panel, an image modulation element such as a display element having a plurality of minute mirrors, and the like, and displays a small image. The projection lens 2 projects the image onto the rear projection screen 3, but since the projection distance is generally long, a reflection mirror 4 is provided in the middle of the optical path in order to reduce the depth of the image display device. These elements are fixed at predetermined positions accommodated in the housing 5.

  FIG. 2 is a schematic diagram showing the structure of the rear projection screen 3 according to the present invention. An enlarged projection image (not shown) projected from the direction of the arrow b is converted into substantially parallel light or light slightly inward by the Fresnel lens sheet 6 and enters the lenticular lens sheet 7. The lenticular lens sheet 7 has a shape in which a plurality of lenticular lenses whose longitudinal direction is the vertical direction of the screen screen are arranged in the horizontal direction of the screen screen as shown in the figure, and functions to diffuse the image light in the horizontal direction of the screen screen. . Further, a black stripe extending in the vertical direction of the screen is formed on the exit surface of the lenticular lens sheet 7 and absorbs external light incident from the screen exit side. Further, a diffusing material 9 is kneaded into the lenticular lens sheet 7 and functions to diffuse the image light in the horizontal and vertical directions of the screen screen. In the embodiment of the rear projection screen of the present invention shown in FIG. 2, the incident angle to the Fresnel lens sheet for enlarged projection projected from the direction of the arrow b on the image generation source side of the Fresnel lens sheet is at least about 40 degrees or more. In this range, the total reflection prism unit 10 is provided which gives incident light to a predetermined incident surface exit angle by the total reflection phenomenon after the first refraction phenomenon.

  The operation of the total reflection prism unit 10 will be described with reference to FIG. FIG. 3 is a longitudinal sectional view of the Fresnel lens sheet 6 according to the present invention shown in FIG. 2, and the position is near the left (right) upper end of the rear projection screen 3 of FIG. The arrow in the figure indicates the direction of the light beam. As shown in FIG. 3, a total reflection type prism unit 19 is provided on the image source side of the Fresnel lens sheet 6 and a refraction type prism unit 11 is provided on the viewing side. A light beam incident from the image source side enters from the c-plane (incident surface) of the total reflection prism unit 10 and is totally reflected by the d surface (total reflection surface), and then is refracted by the refractive prism unit 11 and viewed. The light is emitted substantially horizontally to the viewing side. Although the light beam angle after total reflection can be made substantially horizontal by increasing the angle of the d surface, in the present invention, the angle of the light beam after total reflection is kept large by decreasing the angle of the d surface. The light is refracted by the refracting prism unit 11 and emitted substantially horizontally to the viewing side. The reason for this will be described with reference to FIG.

  FIG. 4 is a longitudinal sectional view of the Fresnel lens sheet 6 according to the present invention, which is a boundary portion where the total reflection prism portion 11 provided on the image source side is provided. As shown in FIG. 4, a predetermined area on the Fresnel lens sheet 6 image source side (an area where image light is incident at a predetermined incident angle (40 degrees) or less) is a flat surface where the total reflection prism portion 10 is not provided. It is an important part (plane part). If the incident angle of the projected image projected from the optical component on the image generation source side to the Fresnel lens sheet 6 is small, the total reflection prism unit 10 cannot be provided. Therefore, in the range where the incident angle of the projected image on the Fresnel lens sheet 6 is small, the image source side is flat and the refractive prism portion is provided on the viewing side as a normal exit surface Fresnel lens. As described above, in the Fresnel lens sheet 6 according to the present invention, the image source side suddenly changes from a flat portion to a portion where the total reflection prism portion 10 is provided. Usually, since the image source side and the viewer side of the Fresnel lens sheet 6 are molded separately, it is necessary to prevent this sudden change from appearing in the image. In the Fresnel lens sheet 6 according to the present invention shown in FIG. 4, the angle α of the light incident on the c-plane of the total reflection prism portion 10 and totally reflected on the d surface and then incident on the refraction-type prism portion 11, and a flat portion After the light is incident from 12 and refracted, the angle β of the light incident on the refractive prism unit 11 is set to be approximately equal. Accordingly, even if the image source side and the viewing side of the Fresnel lens sheet 6 are slightly shifted, the angle of the light beam emitted from the Fresnel lens sheet 6 is kept constant because the angle of the refractive prism portion 11 is almost the same. .

  Next, the prism angle of the refractive prism portion 11 provided on the viewing side of the Fresnel lens sheet 6 according to the present invention will be described with reference to FIGS. 5 (a), 5 (b), 6 (a), and 6 (b). . FIG. 5A is a prism angle of the refractive prism portion 11 provided on the viewing side of the Fresnel lens sheet 6 according to the present invention, and FIG. 5B is a loss of light due to reflection of the same Fresnel lens sheet 6. In both figures, the horizontal axis represents the incident angle of light on the screen. As shown in FIG. 5A, the prism angle of the refractive prism section 11 is constant at 76 degrees from the point that the light incident angle on the screen is 67 degrees. This can be realized by providing the total reflection prism portion 10 on the incident surface from this point. The light loss of the Fresnel lens sheet 6 according to the present embodiment is substantially constant as shown in FIG. 5B, and increases rapidly like the reflection loss of the Fresnel lens sheet according to the prior art shown in FIG. No. 6A is a prism angle of the refractive prism portion 11 provided on the viewing side of the Fresnel lens sheet 6 according to another embodiment of the present invention, and FIG. 6B is a reflection of the same Fresnel lens sheet 6. The horizontal axis represents the incident angle of light on the screen. As shown in FIG. 6A, the prism angle of the refractive prism section 11 gradually decreases from the point that the light incident angle on the screen is 67 degrees. This can be realized by gradually increasing the angle of the d-plane of the total reflection prism portion 10 provided on the incident surface from this point as compared with FIG. At this time, the light loss of the Fresnel lens sheet 6 gradually decreases with the peak of the starting point of the total reflection prism portion 10 as shown in FIG. 6B. Normally, the embodiment of FIG. 5 may be used, but in an image display device in which the periphery is particularly dark, the periphery can be brightened by adopting the embodiment of FIG. In the present invention, the prism angle of the refractive prism portion 11 provided on the viewing side of the Fresnel lens sheet 6 can be freely set within the range shown in FIGS. 5 and 6, so that it can be designed according to the characteristics of the video display device. .

  In FIGS. 5 and 6, the total reflection type prism portion 10 is provided, and the incident angle of light on the screen is as large as 67 degrees, and the loss of light is as large as 35%. A means for reducing these values will be described with reference to FIGS. FIG. 7 is a diagram showing the relationship between the refractive index of the total reflection type prism unit 10 and the light incident angle to the screen. As is apparent from FIG. 7, it can be seen that the refractive index of the total reflection prism portion 10 should be increased in order to reduce the angle of incidence of light on the screen. At least, the refractive index of the total reflection type prism unit 10 is preferably larger than the refractive index of the material of the base material constituting the Fresnel lens sheet. FIG. 8 is a view showing the relationship between the inclination of the incident surface (c-plane) of the total reflection prism portion 10 and the incident angle of light on the screen. The inclination of the incident surface (c surface) of the total reflection type prism unit 10 is expressed by minus the same direction as the total reflection surface (d surface). As can be seen from FIG. 7, in order to reduce the incident angle of light on the screen, the inclination of the incident surface (c-plane) of the total reflection type prism unit 10 of the total reflection type prism unit 10 may be set in the negative direction. . However, in general, if the inclination of the incident surface (c-plane) of the total reflection prism portion 10 is negative, the manufacturing becomes extremely difficult. This manufacturing method will be described later.

  Next, another embodiment of the present invention will be described with reference to FIGS. 9 (a) and 9 (b). FIG. 9A is a longitudinal sectional view of the boundary portion where the total reflection type prism portion 11 of one embodiment of the Fresnel lens sheet 6 according to the present invention is provided, which is the same as that shown in FIG. In the figure, only the light beam passing portion is hatched. The same reference numerals and symbols as those in FIG. 4 denote the same parts and the same parts. As is apparent from the figure, the light beam incident from the flat portion 12 where the total reflection type prism unit 10 on the image source side is not provided enters the refraction type prism unit 11 provided on the viewing side without a break. However, the light beam incident from the total reflection type prism unit 10 on the image source side has a portion without light with respect to the refraction type prism unit 11 provided on the viewing side. The presence of the light-free portion is not a problem if the total reflection prism portion 10 on the image source side and the refraction type prism portion 11 provided on the viewing side are arranged at the same pitch without any deviation, but a little. However, if it deviates, it causes moire. FIG. 9B is a longitudinal sectional view of the boundary portion where the total reflection prism portion of another embodiment of the Fresnel lens sheet according to the present invention is provided. In the figure, only the light beam passing portion is hatched. 9B, reference numeral 14 denotes a total reflection prism portion provided on the image source side of the Fresnel lens sheet 13, reference numeral 15 denotes a refractive prism portion provided on the viewing side, and reference numeral 16 denotes a total reflection type on the image source side. This is a flat portion where the prism portion 14 is not provided. In the Fresnel lens sheet 13 according to the present invention shown in FIG. 9 (b), the light ray enters from the e-plane of the total reflection prism portion 14 and is totally reflected by the f-plane, but the f-plane is formed in a concave shape on the image generation source side. Therefore, the reflected light spreads, and as a result, it is incident on the refractive prism portion 15 provided on the viewing side without any break. Thereby, even if the total reflection type prism unit 14 on the image source side and the refraction type prism unit 15 provided on the viewing side are arranged slightly deviated from each other, moire does not occur.

  In general, the prism portion of the Fresnel lens sheet is molded using an ultraviolet curable resin. However, when the prism is provided on both sides like the Fresnel lens sheet of the present invention, the ultraviolet curable resin does not transmit ultraviolet rays. Therefore, only one side can be molded. Therefore, the Fresnel lens sheet of the present invention can be manufactured by carrying out the manufacturing method shown below.

  FIG. 10 is a diagram for explaining an embodiment of a method for producing a Fresnel lens sheet according to the present invention. A refractive prism 11 is molded on the transparent base material 17 constituting the Fresnel sheet 6. The total reflection prism 10 is molded on the transparent ultraviolet curable resin layer 12 adhered to the surface of the transparent substrate 17 where the refractive prism 11 is not formed. Specifically, after forming the refractive prism portion 11 on the image viewing side by heat compression molding a transparent base material 17 such as polymethyl methacrylate or methyl methacrylate-styrene copolymer, ultraviolet rays are formed on the opposite side. The total reflection prism portion 10 is formed of a cured resin. In the embodiment of FIG. 10, the ultraviolet curable resin adheres not only to the total reflection prism portion 10 but also to the flat portion to form the transparent ultraviolet curable resin layer 18.

  FIG. 11 is a diagram for explaining another embodiment of the method for producing a Fresnel lens sheet according to the present invention. A refractive prism portion 22 is formed on the first transparent ultraviolet curable resin layer 21 adhered to the first transparent substrate 20 constituting the Fresnel lens sheet 19. A second transparent ultraviolet curable resin layer 23 is provided on the surface of the first transparent base material on which the refractive prism 22 is not formed, and a total reflection prism portion 24 is formed thereon. The second transparent ultraviolet curable resin layer 23 on which the total reflection prism portion 24 is formed is formed on the second transparent substrate 25 by the ultraviolet curing method, and then the first transparent substrate 20 is adhered to the first transparent substrate 20 with the adhesive layer 26. Bonded and fixed.

  For the first transparent substrate 20 constituting the Fresnel lens sheet 19, for example, polymethyl methacrylate or a copolymer of methyl methacrylate-styrene can be used. The second transparent substrate 25 of the second transparent ultraviolet curable resin layer 23 on which the total reflection type prism portion 24 is formed is made of polyethylene terephthalate that has been subjected to a surface treatment for facilitating adhesion of the ultraviolet curable resin. A highly transparent acrylic adhesive can be used. In the above description, the second transparent ultraviolet curable resin layer 23 on which the total reflection prism portion 24 is formed is adhered by the adhesive layer 26, but the first transparent ultraviolet curable resin layer 21 on which the refractive prism portion 22 is formed is adhered. Adhering with the layer 26 has the same effect.

  FIG. 12 is a diagram for explaining another embodiment of the method for producing a Fresnel lens sheet according to the present invention. A first transparent ultraviolet curable resin layer 29 on which a refractive prism portion 30 is formed is bonded to a first transparent base material 28 constituting the Fresnel lens sheet 27. On the surface opposite to the surface on which the refractive prism portion 30 is formed, a second transparent ultraviolet curable resin layer 31 on which a total reflection prism portion 32 is formed is provided. The second transparent ultraviolet curable resin layer 31 on which the total reflection prism portion 32 is formed is formed on the second transparent base material 33 by an ultraviolet curable method, and then is adhered to the first transparent base material 28 by the adhesive layer 34. Bonded and fixed. In the embodiment of FIG. 12, the second transparent ultraviolet curable resin layer 31 on which the total reflection prism portion 32 is formed is divided into four. Further, the second transparent ultraviolet curable resin layer 31, the second transparent base material 33, and the adhesive layer 34 in portions where the total reflection prism portion 32 is not formed are omitted. This embodiment is effective when the part where the total reflection type prism portion 32 is provided is only the corner portion of the Fresnel lens sheet 27. Further, the second transparent ultraviolet curable resin layer 31 on which the total reflection type prism portion 32 to be bonded is formed may be the same at all four locations, and may be trimmed if necessary. Further, in this embodiment, the second transparent ultraviolet curable resin layer 31 having total reflection type prism portions 32 formed at all four corners is bonded. However, according to the requirements of the optical system, the upper, lower, right and left portions are bonded. It is good also as two places thru | or one arbitrary corner each. When the second transparent ultraviolet curable resin layer 31 on which the total reflection type prism portion 32 is formed as shown in FIG. 12 is divided, the inclination of the incident surface (c surface) of the total reflection type prism portion 10 as described above. Even if it is set to minus, it can be manufactured relatively easily. When the mold is released from the mold, it may be moved in the direction of the center of curvature of the Fresnel. Even if the incident surface (c-plane) of the total reflection prism portion 10 is slightly inclined in the minus direction, the second transparent ultraviolet curable resin layer 31 is used. And if the 2nd transparent base material 33 is made into the material which is easy to bend, mold release from a type | mold will be attained.

  According to the present invention, in order to reduce the depth of the video display device, the optical axis center of the projection lens is set near the lower end of the rear projection screen, and the screen incident angle of the video light incident on the left and right upper ends of the rear projection screen is Even if it becomes excessive, the reflection loss of the screen can be suppressed. Further, according to the present invention, it is possible to reduce the moire phenomenon that occurs in the Fresnel lens sheet. Thus, according to the present invention, it is possible to obtain a bright image display device up to the upper left and right ends of the screen.

1 is a partial cross-sectional perspective view showing an embodiment of a video display device according to the present invention. It is a schematic diagram which shows the structure of the rear projection type screen 3 of the video display apparatus shown in FIG. It is a longitudinal cross-sectional view of the Fresnel lens sheet 6 according to the present invention shown in FIG. It is a longitudinal cross-sectional view of the Fresnel lens sheet 6 by this invention, and is a boundary part in which the total reflection type prism part 11 provided in the image source side is provided. The prism angle of the refractive prism portion 11 provided on the viewing side of the Fresnel lens sheet 6 according to the present invention and the light loss due to the reflection of the same Fresnel lens sheet 6 are shown. The prism angle of the refraction type prism part 11 provided in the viewing side of the Fresnel lens sheet 6 by the other Example of this invention, and the loss of light by reflection of the same Fresnel lens sheet 6 are shown. It is the figure which showed the relationship between the refractive index of the total reflection type prism part 10, and the light ray incident angle to a screen. It is the figure which showed the relationship between the inclination of the incident surface (c surface) of the total reflection type prism part 10, and the light ray incident angle to a screen. The longitudinal cross-sectional view of the boundary part in which the total reflection type prism part 11 of one Example of the Fresnel lens sheet 6 by this invention is provided, and the boundary in which the total reflection type prism part of the other Example of the Fresnel lens sheet by this invention is provided It is a longitudinal cross-sectional view of a part. It is a figure explaining one Example of the manufacturing method of the Fresnel lens sheet by this invention. It is a figure explaining the other Example of the manufacturing method of the Fresnel lens sheet by this invention. It is a figure explaining the other Example of the manufacturing method of the Fresnel lens sheet by this invention. It is a figure which shows the limit of thickness reduction of the optical system by the wide angle of the projection lens. 6 is a diagram showing a reduction in the thickness of the optical system when the optical axis center of the projection lens 52 is set at the lower end center of the rear projection screen 53. FIG. It is the figure which showed the relationship between the light ray incident angle to the screen of a common output surface Fresnel lens, and reflection loss.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image generation source, 2 ... Projection lens, 3 ... Rear projection type screen, 4 ... Reflection mirror, 5 ... Case, 6, 13, 19, 27 ... Fresnel lens sheet, 7 ... Diffusion sheet, 10, 14, 24 , 32 ... Total reflection type prism part, 11, 15, 22, 30 ... Refraction type prism part, 12, 16 ... Flat part where the total reflection type prism part on the image source side is not provided, 17, 20, 25, 28,33 ... transparent substrate, 18,21,23,29,31 ... transparent UV curable resin layer, 26,34 ... adhesive layer

Claims (2)

A video source,
An optical component for enlarging and projecting the image of the image source;
A rear projection screen for projecting a projection image projected from the optical component;
With
The rear projection type screen includes at least a double-sided Fresnel lens sheet on the image generation source side and a diffusion sheet for diffusing image light on the image viewing side as its component parts, and the optical image on the image generation source side of the double-sided Fresnel lens sheet. In the range where the incident angle of the projection image projected from the component to the double-sided Fresnel lens sheet is at least approximately 40 degrees or more, the incident light is all given a predetermined incident surface exit angle by the total reflection phenomenon after the first refraction phenomenon. In a video display device having a reflective prism portion, and having a refractive prism portion that emits as a light beam having a predetermined emission angle by a second refraction phenomenon on a video viewing side of the double-sided Fresnel lens sheet,
The prism angle of the refractive prism portion provided on the image viewing side of the double-sided Fresnel lens sheet is
In a range where the light from the image generation source side of the double-sided Fresnel lens sheet is a flat plate having a angle less than a predetermined incident angle, the projection angle projected from the optical component increases as the incident angle to the double-sided Fresnel lens sheet increases. Is the angle
An image display apparatus characterized in that the projected image has an angle that is constant or reduced from the vicinity of a position where the projected image passes through a total reflection prism portion provided on the image generation source side. The video display device according to claim 1,
A predetermined incident surface exit angle obtained by a first refraction phenomenon and a total reflection phenomenon at a starting point of a total reflection prism portion provided on the image generation source side of the double-sided Fresnel lens sheet, An image display device characterized in that a predetermined incident surface exit angle obtained by a third refraction phenomenon in a portion where there is no total reflection type prism portion adjacent to the start point of the reflection type prism portion is substantially equal.

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