JP5151101B2 - Lens film and display device - Google Patents

Description

  The present invention relates to a light transmissive lens film and a display device incorporating the lens film.

  In recent years, liquid crystal display devices are being replaced by cathode ray tubes (CRTs), which have been the mainstream of display devices, due to advantages such as low power consumption and space saving, and cost reduction.

  In the liquid crystal display device, for example, there are several types classified according to the illumination method when displaying an image. As a typical example, transmission using a light source disposed behind the liquid crystal panel is performed. Type display device.

  In such a transmissive display device, increasing the display luminance and widening the viewing angle are particularly important for increasing the commercial value of the display device. Therefore, a diffusion sheet is provided between the lens film and the liquid crystal panel, the divergence angle of this diffusion sheet is made larger than that of the lens film, and the light output of the light source is increased, thereby widening the viewing angle and increasing the viewing angle. It is conceivable to compensate for the decrease in luminance. However, if the light output of the light source is increased, the power consumption increases, which is not preferable for a liquid crystal display device in which low power consumption is one of the appeal points. Therefore, the display brightness and viewing angle can be optimized by improving the optical gain characteristics and light distribution characteristics of projection optical components such as lens films and diffusion sheets without increasing the light output of the light source. Is strongly desired.

  Here, the lens film is generally configured by arranging a plurality of triangular prisms in parallel along the extending direction as shown in Patent Documents 1 and 2, and the bottom side of each prism. A part of the light incident from the light beam is refracted and transmitted, thereby increasing the directivity. On the other hand, the diffusion sheet generally spreads the viewing angle by diffusing light whose directionality is enhanced by a lens film within a range of a predetermined diffusion angle.

Special table 2003-511735 gazette JP-T-2002-504698

  As described above, the diffusion sheet is used to increase the viewing angle, but there is a problem that the cost and thickness of the display device increase by providing the diffusion sheet. Further, since the diffusion sheet is provided between the lens film and the liquid crystal panel, there is a problem that display luminance is inevitably lowered.

  The present invention has been made in view of such problems, and the object thereof is to increase the viewing angle while minimizing the decrease in display luminance without increasing the cost and thickness of the display device. A lens film and a display device including the lens film are provided.

The lens film of the present invention is configured by arranging a plurality of convex lens bodies extending in the same plane in parallel along the extending direction. Each lens body has two inclined surfaces in contact with the top of the lens body, and has a plurality of curved surfaces protruding from the inclined surface at a portion that is a part of the inclined surface and does not contact the top of the lens body. doing. In all the curved surfaces formed on the inclined surface, the curved surface formed on one inclined surface and the curved surface formed on the other inclined surface are arranged at positions facing each other with the top of the lens body in between. . Each curved surface has a curve forming a part of a sine curve in the extending direction of the lens body, and has an aspherical curve in the arrangement direction of the lens bodies.

The display device of the present invention includes a panel driven based on an image signal, a light source that emits light for illuminating the panel, and a lens film provided between the panel and the light source. The lens film is configured by arranging a plurality of convex lens bodies extending in the same plane in parallel along the extending direction, and each lens body has two slopes in contact with the top of the lens body. In addition to having a surface, it has a plurality of curved surfaces protruding from the inclined surface at a part of the inclined surface and not in contact with the top of the lens body. In all the curved surfaces formed on the inclined surface, the curved surface formed on one inclined surface and the curved surface formed on the other inclined surface are arranged at positions facing each other with the top of the lens body in between. . Each curved surface has a curve forming a part of a sine curve in the extending direction of the lens body, and has an aspherical curve in the arrangement direction of the lens bodies.

  In the lens film of the present invention and the display device including the lens film, each lens body is provided with an inclined surface that is obliquely opposed to the plane, and a plurality of curved surfaces that protrude from the inclined surface are provided on a part of the inclined surface. Therefore, the light incident from the opposite side of the inclined surface of the lens film is refracted by the inclined surface, increasing the directivity, and being refracted by the curved surface provided in a part of the inclined surface, and having a predetermined diffusion angle. Diffused within range.

  According to the lens film and the display device of the present invention, each lens body is provided with an inclined surface that is obliquely opposed to the plane, and a plurality of curved surfaces protruding from the inclined surface are provided on a part of the inclined surface. Therefore, the directivity of light incident from the side opposite to the inclined surface of the lens film can be increased, and the light incident from the side opposite to the inclined surface of the lens film can be diffused within a predetermined diffusion angle range. . That is, since the lens film serves not only as a condenser lens but also as a diffusion sheet, it is not necessary to provide a diffusion sheet separately. As a result, the viewing angle can be expanded while minimizing the decrease in display luminance without increasing the cost and thickness of the display device.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a cross-sectional structure of a display device 1 according to an embodiment of the present invention. The display device 1 is a transmissive display device that displays an image by active matrix driving.

  The display device 1 includes a liquid crystal panel 20 and a lighting device 10 disposed behind the liquid crystal panel 20, and the surface of the liquid crystal panel 20 is directed toward an observer (not shown). In the present embodiment, for convenience, it is assumed that the liquid crystal panel 20 is arranged so that the surface thereof is orthogonal to the horizontal plane.

  The liquid crystal panel 20 has a laminated structure having a liquid crystal layer 26 between a transparent substrate 22 on the observation side and a transparent substrate 29 on the illumination device 10 side. Specifically, the polarizing plate 21, the transparent substrate 22, the color filter 23, the transparent electrode 24, the alignment film 25, the liquid crystal layer 26, the alignment film 27, the transparent pixel electrode 28, the transparent substrate 29, and the polarizing plate 30 in this order from the observation side. Have

  The polarizing plates 21 and 30 are a kind of optical shutter, and allow only light (polarized light) in a certain vibration direction to pass therethrough. The polarizing plates 21 and 30 are arranged so that their polarization axes are different from each other by 90 degrees, so that the light emitted from the illumination device 10 is transmitted or blocked through the liquid crystal layer 26. ing.

  The transparent substrates 22 and 29 are made of a substrate that is transparent to visible light, such as plate glass. Although not shown, the transparent substrate 29 on the illumination device 10 side includes an active drive circuit including a TFT (Thin Film Transistor) as a drive element electrically connected to the transparent pixel electrode 28 and wiring. Is formed.

  The color filter 23 is configured by arranging color filters for separating the emitted light from the lighting device 10 into, for example, three primary colors of red (R), green (G), and blue (B).

  The transparent electrode 24 is made of, for example, ITO (Indium Tin Oxide) and functions as a common counter electrode.

  The alignment films 25 and 27 are made of, for example, a polymer material such as polyimide, and perform an alignment process on the liquid crystal.

  The liquid crystal layer 26 is made of, for example, liquid crystal in a VA (Vertical Alignment) mode, a TN (Twisted Nematic) mode, or an STN (Super Twisted Nematic) mode, and light emitted from the illumination device 10 is applied by a voltage applied from a drive circuit (not shown). Has a function of transmitting or blocking each pixel.

  The transparent pixel electrode 28 is made of, for example, ITO and functions as an electrode for each pixel.

  The illuminating device 10 includes, in order from the observation side, a laminated structure in which lens films 12 and 13, a diffusion sheet 14, a light guide plate 16, and a reflection sheet 17 are laminated, and a light source 11 disposed on a side surface of the laminated structure. And a lamp reflector 15 disposed around the light source 11. A part of the lamp reflector 15 is opened toward the laminated structure. Thus, this illumination device 10 has a so-called edge light type configuration.

  The light source 11 includes, for example, a cold cathode fluorescent lamp called a cold cathode fluorescent lamp (CCFL), a light emitting diode (LED), or the like.

  The lamp reflector 15 has a function of reflecting a part of light emitted from the light source 11 in the direction of the light guide plate 16. Thereby, the emitted light from the light source 11 can be used efficiently.

  The light guide plate 16 has a function of propagating the light emitted from the light source 11 while totally reflecting it and spreading the light over the entire surface of the liquid crystal panel 20. Thereby, the emitted light from the light source 11 can be made into planar light.

  The reflection sheet 17 has a function of reflecting light that is about to leak from the light guide plate 16 to the inside of the light guide plate 16. Thereby, similarly to the lamp reflector 15 described above, the light emitted from the light source 11 can be used efficiently.

  The diffusion sheet 14 has a function of diffusing planar light spread over the entire surface of the liquid crystal panel 20 by the light guide plate 16 and reducing unevenness in brightness. Thereby, light with uniform brightness is irradiated on the entire surface of the liquid crystal panel 20.

  Each of the lens films 12 (13) is made of a transparent synthetic resin, and is preferably formed of a thermoplastic resin such as a polycarbonate resin in consideration of cost and productivity. The lens film 12 (13) has a thickness that does not cause inconvenience in handling, for example, a thickness of about 150 μm to 300 μm.

  The lens film 12 (13) has a plurality of portions extending in a plane parallel to the bottom surface 12A (13A) of the lens film 12 (13) as schematically shown in an enlarged view of a part of FIG. It has a structure in which triangular prisms 12-1 (13-1) are arranged along the extending direction. Each prism 12-1 (13-1) corresponds to an example of the “lens body” of the present invention.

  The lens film 12 (13) is arranged so that its bottom surface 12 A (13 A) is parallel to the surface of the liquid crystal panel 20. At this time, for example, the prism 12-1 extends in the horizontal direction (a direction perpendicular to the paper surface of FIG. 1), and the prism 13-1 is perpendicular to the extending direction of the prism 12-1. Extending in various directions (for example, the vertical direction).

  The prism 12-1 (13-1) has inclined surfaces 12C (13C) and 12D (13D) in contact with the apex portion 12B (13B) of the apex angle θ, and the inclined surface 12C is part of the inclined surface 12C (13C). A plurality of curved surfaces 12E (13E) projecting from (13C) and a plurality of curved surfaces 12F (13F) projecting from the tilted surface 12D (13D) are part of the tilted surface 12D (13D). In addition, the inclined surfaces 12C (13C) and 12D (13D) are disposed obliquely facing the bottom surfaces 12A (13A) of the lens films 12 and 13.

  Here, the apex angle θ and the surface shapes of the inclined surfaces 12C (13C) and 12D (13D) depend on the magnitude of the front luminance required for the light emitted from the prism 12-1 (13-1). It is properly adjusted. The apex angle θ is adjusted to a value within a range larger than 0 ° and smaller than 180 °, for example, 90 °. On the other hand, the surface shapes of the inclined surfaces 12C (13C) and 12D (13D) are, for example, flat or convex. It has a curved surface. Thereby, the inclined surfaces 12C and 12D function as a condensing lens that condenses light incident from the bottom surface 12A and mainly adjusts the vertical viewing angle, while the inclined surfaces 13C and 13D are incident from the bottom surface 12B. It functions as a condensing lens that condenses light and mainly adjusts the horizontal viewing angle.

  The surface shapes, sizes, and arrangements of the curved surfaces 12E (13E), 12F (13F) are appropriately adjusted according to the size of the viewing angle required for the display device 1 and the uniformity of display luminance. The curved surfaces 12E (13E) and 12F (13F) are substantially symmetric with respect to the top portion 12B (13B), for example, as shown in FIG. 3A (cross-sectional shape in the direction of arrows AA in FIG. 2). It has a shape. Also, for example, as shown in FIGS. 3A and 3B (cross-sectional shape in the direction of arrows BB in FIG. 2), the sign extends in the extending direction of the prism 12-1 (13-1). It has a curve forming a part of the curve, and has an aspherical curve in the arrangement direction of the prisms 12-1 (13-1). Accordingly, the curved surfaces 12E (13E) and 12F (13F) function as a diffusion sheet that diffuses light incident from the bottom surface 12A (12B). Therefore, the lens film 12 (13) not only serves as a condenser lens but also serves as a diffusion sheet.

  In FIGS. 2, 3A, and 3B, the curved surface 12E (13E) and the curved surface 12F (13F) are spatially separated from each other via the top portion 12B (13B). As shown in FIG. 5, the curved surface 12E may be configured by integrating the curved surface 12E (13E) and the curved surface 12F (13F). In FIGS. 2, 3A, and 3B, the curved surfaces 12E (13E) and 12F (13F) are arranged at periodic intervals. For example, as shown in FIG. You may arrange | position with a space | interval. In FIGS. 2, 3A, and 3B, the curved surfaces 12E (13E) and 12F (13F) have the same size. For example, as shown in FIG. You may do it. 2, 3 </ b> A, 3 </ b> B, and 4, the prism 12-1 and the prism 13-1 have the same shape, but may have different shapes. Further, the curved surfaces 12E and 12F may be provided only for the prism 12-1, and the curved surfaces 13E and 13F may not be provided for the prism 13-1. Further, the curved surfaces 13E and 13F may be provided only for the prism 13-1, and the curved surfaces 12E and 12F may not be provided for the prism 12-1. In any case, the apex angle θ or the inclined surface 12C depends on the size of the front luminance required for the display device 1, the size of each of the horizontal viewing angle and the vertical viewing angle, the uniformity of the display luminance, and the like. The surface shapes of (13C) and 12D (13D), and the curved surfaces 12E (13E) and 12F (13F) are the surface shapes, sizes, and examples illustrated in FIG. 2, FIG. 3 (A), (B), and FIG. Each is adjusted to the arrangement.

  Next, an example (melt extrusion molding method) of forming the lens film 12 (13) having such a configuration will be described.

FIG. 5 shows a schematic configuration of the lens film manufacturing apparatus 36 . The lens film manufacturing apparatus 36 heats the transparent resin 12X (13X) supplied from the supply apparatus 35 that supplies the molten transparent resin 12X (13X) and the supply apparatus 35, and forms a prism shape on the transparent resin 12X (13X). The transfer device 32 is configured to transfer and form the lens film 12 (13).

  Here, the transfer device 32 is a press roll 33 that rotates about the rotation axis X, and a forming roll that rotates about a rotation axis Y parallel to the rotation axis X and has a heater (not shown) inside. 34. A prism shape obtained by inverting the surface shape of the lens film 12 (13) is formed on the peripheral surface of the forming roll 34. Specifically, as will be described later, a plurality of grooves 34A are formed in parallel on the peripheral surface of the forming roll 34, and a plurality of depressions 34C are intermittently formed on the inner wall 34B of each groove 34A. Yes.

In this lens film manufacturing apparatus 36 , after the transparent resin 12X (13X) supplied from the supply apparatus 35 is temporarily held in a mortar-shaped part formed by the gap between the pressing roll 33 and the forming roll 34, As the pressing roll 33 and the forming roll 34 rotate, they are sent out below the gap. The sent transparent resin 12X (13X) is pressed against the peripheral surface of the forming roll 34 by the pressure from the pressing roll 33, and is solidified by heat from the heater in the forming roll 34. Thereby, the prism shape formed on the peripheral surface of the forming roll 34 is transferred to the transparent resin 12X (13X), and the lens film 12 (13) is formed.

  Next, an example of a method for manufacturing the forming roll 34 described above will be described with reference to FIGS. 6 (A), 6 (B), 7 (A), and 7 (B). 6A and 7A show a schematic configuration for explaining the manufacturing process of the forming roll 34, and FIG. 6B shows a cross-sectional configuration of FIG. 6A. 7 (B) represents the cross-sectional structure of FIG. 7 (A).

  First, a roll 34D having no irregularities on its peripheral surface is prepared. As shown in FIGS. 6A and 6B, this roll 34D is rotated, and a cutting tool 40 having a triangular tip is formed on the peripheral surface of the roll 34D. Push it. As a result, the peripheral surface of the roll 34D is scraped, and a triangular columnar groove 34A is formed in an annular shape on the peripheral surface. Next, after separating the cutting tool 40 from the peripheral surface of the roll 34D, the cutting tool 40 is moved in the longitudinal direction of the roll 34D (the arrow direction in FIG. 6). Then, the cutting tool 40 is pressed against the circumferential surface of the roll 34D along the previously formed groove 34A. As a result, the peripheral surface of the roll 34D is cut, and a new triangular prism-shaped groove 34A is formed in an annular shape on the peripheral surface. By repeating this a predetermined number of times, as shown in FIG. 7A, a plurality of grooves 34A are formed in parallel on the peripheral surface.

Subsequently, as shown in FIGS. 7A and 7B, the center of an aspherical bit 41 (see FIG. 7B) whose tip shape is represented by the following formula (1) is rolled, for example. The groove 34A is aligned with the center of the groove 34A formed in 34D, and intermittently presses against the inner wall 34B of the groove 34A. As a result, the inner wall 34B is shaved, and a recess 34C intermittently aligned with the inner wall 34B is formed. At this time, the frequency f and the maximum amplitude value a byte 41 is vibrated in the radial direction of the roll 34D, and by controlling the initial position y ₀ in the radial direction of the roll 34D byte 41, the period and depth of the recess 34C It can be changed freely. For example, when the cutting tool 41 is periodically pressed against the inner wall 34B so as to draw a sine curve as shown in the following formula (2), for example, as shown in FIG. The depressions 34C are formed periodically in a line. In this way, the forming roll 34 is manufactured.

z = x ² / (R + √ (R ² − (1 + K) × x ² )) + A × x ⁴ (1)
y = a × sin ((4π ² × r × f / p) × t) + y ₀ (2)

  Here, z is a coordinate in the radial direction of the roll 34D, x is a coordinate in the arrangement direction of the grooves 34A, R is a radius of curvature, K is a conic constant, and A is a fourth-order aspheric coefficient. is there. Further, y is the vertical position of the cutting tool 41, r is the radius of the roll 34D, and p is the number of aspherical protrusions per circumference of the roll 34D.

  Next, the basic operation when displaying an image in the display device 1 incorporating the lens films 12 and 13 formed in this way will be described.

First, in the illuminating device 10, the light emitted from the light source 11 is reflected by the lamp reflector 15 and the reflection sheet 17 , directed toward the liquid crystal panel 20, and then spread over the entire surface of the liquid crystal panel 20 by the light guide plate 16. The light is evenly diffused by the liquid crystal panel 2 and emitted to the liquid crystal panel 2 through the lens films 12 and 13.

  In the liquid crystal panel 2, the incident light from the illumination device 10 is transmitted according to the magnitude of the voltage applied to each pixel between the transparent pixel electrode 28 and the transparent electrode 24 as the counter electrode, and the color filter 23. To separate the colors and inject them to the viewing side. Thereby, a color image display is performed.

  By the way, in the present embodiment, each prism 12-1 (13-1) constituting the lens film 12 (13) is obliquely opposed to the bottom surface 12A (12B) of the lens film 12 (13) and is planar. Alternatively, the inclined surfaces 12C (13C) and 12D (13D) having convex curved surfaces are provided, and further, the inclined surfaces 12C (13C) and 12D (13D) are part of the inclined surfaces 12C (13C) and 12D (13D). Since a plurality of protruding curved surfaces 12E (13E) and 12F (13F) are provided, the light incident from the bottom surface 12A (12B) is refracted by the inclined surfaces 12C (13C) and 12D (13D) to increase directivity. In addition, the light is refracted by the curved surfaces 12E (13E) and 12F (13F) and diffused within a predetermined diffusion angle range. As a result, the brightness and the viewing angle can be changed to some extent in a range different from the conventional case where a curved surface is not provided in a part of each prism.

  As described above, in the present embodiment, the lens film 12 (13) is provided with not only a function of a condenser lens but also a function of a diffusion sheet, so that it is not necessary to provide a diffusion sheet separately. Accordingly, the viewing angle can be expanded while minimizing the decrease in display luminance without increasing the cost and thickness of the display device 1.

  In particular, in the present embodiment, the viewing angle can be finely adjusted by appropriately adjusting the shape, size, and arrangement of the curved surfaces 12E (13E) and 12F (13F). Thereby, when it is desired to finely adjust the viewing angle, it is not necessary to separately provide a diffusion sheet in order to finely adjust the viewing angle. Thereby, it is possible to finely adjust the viewing angle while minimizing the decrease in display luminance without increasing the cost and thickness of the display device 1.

  Moreover, in this Embodiment, the period of each prism 12-1 (13-1) which comprises the lens film 12 (13) by arrange | positioning irregularly the arrangement | positioning of the curved surfaces 12E (13E) and 12F (13F). It is possible to mitigate light and darkness (moire) of light generated due to the property. Accordingly, it is not necessary to provide a separate diffusion sheet to alleviate moire. Thereby, it is possible to alleviate moire while minimizing the decrease in display luminance without increasing the cost and thickness of the display device 1.

[Example]
Next, an example of the lens film 12 of the present embodiment will be described in comparison with a lens film according to a comparative example.

In the first embodiment, the radius r of the roll 34D is 150 mm, the rotation frequency f of the roll 34D is 30 Hz, and the number p of times that the cutting tool 41 is vibrated in the radial direction of the roll 34D during the rotation of the roll 34D is 11775. The initial position y ₀ in the radial direction of the roll 34D of the cutting tool 41 is set to 138.8 μm, the maximum amplitude value a when the cutting tool 41 is vibrated in the radial direction of the roll 34D is set to 20.0 μm, and the curvature radius R is 25 μm. And the conic constant K is −10, the fourth-order aspheric coefficient A is 0.00005, and the inclined surfaces 12C and 12D of each prism 12-1 are formed, and the curved surfaces 12E and 12F are formed periodically. Thus, a lens film 12 was formed (see FIG. 9A).

In the second embodiment, the radius r of the roll 34D, the rotation frequency f of the roll 34D, the initial position y _{0 of} the cutting tool 41, the radius of curvature R, the conic constant K, and the fourth-order aspherical coefficient A are set. The same as the first embodiment, the number of times p that the cutting tool 41 is vibrated in the radial direction of the roll 34D during one rotation of the roll 34D is 18849, and the maximum amplitude when the cutting tool 41 is vibrated in the radial direction of the roll 34D. The value a is set to 21.2 μm, and the inclined surfaces 12C and 12D of each prism 12-1 are formed, and the curved surfaces 12E and 12F are formed periodically to form the lens film 12 (see FIG. 9B). .

In the third embodiment, the values of the radius r of the roll 34D and the rotation frequency f of the roll 34D are made equal to those of the first embodiment, and the cutting tool 41 is moved to the diameter of the roll 34D while the roll 34D rotates once. The number of vibrations p in the direction p is set to 18849, the initial position y ₀ in the radial direction of the roll 34D of the cutting tool 41 is set to 279.7 μm, and the maximum amplitude value a when the cutting tool 41 is vibrated in the radial direction of the roll 34D is 42 μm. The curvature radius R is 10 μm, the conic constant K is −3, the fourth-order aspheric coefficient A is 0.00003, and the inclined surfaces 12C and 12D of each prism 12-1 are formed, and the curved surfaces 12E and 12F are formed. The lens film 12 was formed by periodically forming (see FIG. 9C).

  In addition, the lens film which concerns on a comparative example is corresponded to the case where the curved surfaces 12E and 12F are not formed in FIG. 9 (A).

  FIGS. 10A and 10B show the relationship between the viewing angle and the display luminance when the lens film 12 according to the first to third examples or the lens film according to the comparative example is mounted on the display device 1. FIG. 10A shows the relationship between the horizontal viewing angle and the display brightness, and FIG. 10B shows the relationship between the vertical viewing angle and the display brightness. Here, the horizontal axis of FIGS. 10A and 10B is the viewing angle, and the vertical axis is the display luminance normalized by the value of the comparative example. In the present example and the comparative example, a lens film (lens film corresponding to the lens film 13 in the above embodiment) in which each prism extends in the vertical direction is not mounted.

  10 (A) and 10 (B), as the size of the curved surface of each prism 12-1 is gradually increased, the horizontal viewing angle and the vertical viewing angle become larger than those in the comparative example, and display luminance is inversely proportional to the horizontal viewing angle. It turns out that becomes small compared with a comparative example. In this way, by changing the size of the curved surface of each prism 12-1, it is possible to change to some extent the luminance and the viewing angle in a range different from the conventional case where a curved surface is not provided in a part of the prism.

  In other words, in the present embodiment, the lens film 12 has not only a role of a condenser lens but also a role of a diffusion sheet, so that it is not necessary to provide a diffusion sheet separately. Accordingly, the viewing angle can be expanded while minimizing the decrease in display luminance without increasing the cost and thickness of the display device 1.

  In the present embodiment, the horizontal viewing angle and the vertical viewing angle can be continuously changed by appropriately adjusting the size of the curved surface of each prism 12-1. Therefore, when it is desired to finely adjust these viewing angles, it is not necessary to separately provide a diffusion sheet in order to finely adjust these viewing angles. Thereby, it is possible to finely adjust the viewing angle while minimizing the decrease in display luminance without increasing the cost and thickness of the display device 1.

  While the present invention has been described with reference to the embodiments and the examples thereof, the present invention is not limited to these embodiments and the like, and various modifications are possible.

  For example, in the above-described embodiment and the like, the configuration of the display device 1 has been specifically described, but it is not necessary to include all layers, and other layers (for example, a reflective polarizing plate) may be included. Good. That is, various selections can be made according to applications and purposes.

  In the above embodiments and the like, the case of the active matrix display device 1 has been described. However, the present invention can also be applied to the case of simple matrix driving.

  Further, in the above-described embodiments and the like, the case of the liquid crystal display device 1 has been described, but it is of course applicable to a display device using other principles.

  Moreover, in the said embodiment etc., although the lens film 12 (13) was formed by the melt extrusion molding method, it is of course possible to form it by other manufacturing methods. For example, the lens film 12 (13) has, for example, (1) a synthetic resin laminated on a sheet mold having a shape obtained by inverting the surface shape of the lens film 12 (13), and the sheet mold is peeled off to remove a prism on the surface. A method of transferring the shape, or (2) injection molding in which a molten resin is injected into a mold having a shape obtained by inverting the surface shape of the lens film 12 (13) and the prism shape is transferred to the surface by solidifying the resin. Method (3) The sheet-shaped resin is heated and the prism is formed on the surface by pressing the lens film 12 (13) between a metal mold and a mold having a shape obtained by inverting the surface shape. (4) A base film is applied to a roll having a shape obtained by applying a UV curable resin to a base film and inverting the surface shape of the lens film 12 (13). With pressing the coated UV curing resin, ultraviolet is irradiated with can be formed by a method of transferring a prism shape on the surface by solidifying the UV curable resin.

1 is a cross-sectional view illustrating an example of a configuration of a display device according to an embodiment of the present invention. It is a perspective view showing an example of a structure of the lens film of FIG. It is a cross-sectional block diagram of the lens film of FIG. It is a perspective view showing the other example of a structure of the lens film of FIG. It is a schematic diagram showing an example of a structure of a lens film manufacturing apparatus. It is the schematic for demonstrating the manufacturing method of the transfer apparatus of FIG. It is the schematic for demonstrating the manufacturing method following FIG. It is the schematic for demonstrating the manufacturing method following FIG. It is an expansion perspective view showing an example of composition of a lens film concerning an example. FIG. 10 is a relationship diagram between the viewing angle of the lens film of FIG. 9 and display luminance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 10 ... Illuminating device, 11 ... Light source, 12, 13 ... Lens film, 12A, 13A ... Bottom surface, 12B, 13B ... Top part, 12C, 12D, 13C, 13D ... Inclined surface, 12E, 12F, 12G, 13E, 13F, 13G ... curved, 12X, 13X ... transparent resin, 12-1,13-1 ... prism, 14, 31 ... diffusing sheet, 15 ... lamp reflector, 16 ... light guide plate, 17 ... reflection sheet, 20 ... liquid crystal Panels 21, 30 ... Polarizing plates 22, 29 ... Transparent substrates, 23 ... Color filters, 24 ... Transparent electrodes, 25, 27 ... Alignment films, 26 ... Liquid crystal layers, 28 ... Transparent pixel electrodes, 32 ... Transfer devices, 33 ... Pressing roll, 34 ... Forming roll, 34A ... Groove, 34B ... Inner wall, 34C ... Depression, 34D ... Roll, 35 ... Supplying device, 36 ... Lens film manufacturing device, 40 , 41 ... Light, X, Y ... rotation axis.

Claims (5)

A lens film in which a plurality of convex lens bodies extending in the same plane are arranged in parallel along the extending direction,
Each of the lens bodies has two inclined surfaces in contact with the top of the lens body, and a plurality of protrusions protruding from the inclined surface at a portion that is a part of the inclined surface and does not contact the top of the lens body. Has a curved surface,
Of all the curved surfaces formed on the inclined surface, the curved surface formed on one inclined surface and the curved surface formed on the other inclined surface are arranged at positions facing each other with the top of the lens body in between. and,
Each of the curved surfaces has a curve forming a part of a sine curve in the extending direction of the lens body, and an aspherical curve in the arrangement direction of the lens body . The lens film according to claim 1, wherein the curved surface formed on one inclined surface and the curved surface formed on the other inclined surface are arranged at positions symmetrical to each other about the top of the lens body. The lens film according to claim 1, wherein the plurality of curved surfaces are periodically arranged in an extending direction of the lens body. The lens film according to claim 1, wherein the plurality of curved surfaces are irregularly arranged in an extending direction of the lens body. A panel driven based on an image signal;
A light source that emits light for illuminating the panel;
A lens film provided between the panel and the light source,
The lens film is configured by arranging a plurality of convex lens bodies extending in the same plane in parallel along the extending direction,
Each of the lens bodies has two inclined surfaces in contact with the top of the lens body, and a plurality of protrusions protruding from the inclined surface at a portion that is a part of the inclined surface and does not contact the top of the lens body. Has a curved surface,
Of all the curved surfaces formed on the inclined surface, the curved surface formed on one inclined surface and the curved surface formed on the other inclined surface are arranged at positions facing each other with the top of the lens body in between. and,
Each of the curved surfaces has a curve forming a part of a sine curve in the extending direction of the lens body, and an aspherical curve in the arrangement direction of the lens body .

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