JP2012058275A - Method for manufacturing lens sheet, lens sheet, surface light source device and transmissive display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a lens sheet, for easily manufacturing a lens sheet having high accuracy of the shape or the like even when the lens pattern has a fine pitch, and hardly causing distortion in an image or the like, and to provide the lens sheet, and a surface light source and a transmissive display device including the lens sheet.SOLUTION: The method for manufacturing a lens sheet includes: a lens layer forming step of forming a lens layer in which a plurality of unit lenses are arrayed on one surface of a substrate layer; a coating film forming step of forming a coating film of an ionization radiation-curable resin on the opposite surface to the surface where the lens layer is formed; an exposure step of irradiating the coating film from the lens layer side with approximately parallel beams of ionization radiation along a direction approximately perpendicular to the surface of the substrate layer, so as to expose and cure a portion of the coating film where the ionization radiation transmits; and a removing step of removing an uncured portion of the coating film by a developing process. In the lens layer forming step, the unit lenses are formed so that an array pitch P satisfies 40 μm≤P≤140 μm, and the substrate layer having a thickness T which satisfies 25 μm≤T≤50 μm is used.

Description

  The present invention relates to a lens sheet manufacturing method, a lens sheet, a surface light source device including the lens sheet, and a transmissive display device.

In recent years, demand for display devices capable of displaying stereoscopic images has increased.
As a method for displaying a stereoscopic image, for example, left-eye image light and right-eye image light having parallax are converted into linearly polarized light having different polarization planes, and the images reach each eye using polarized glasses. Switching between images that allow the left and right eyes to be viewed with observation glasses so that left-eye video and right-eye video with parallax displayed in a time-sharing manner reach the left and right eyes of the observer, respectively. There is. However, in such a display device using glasses, there are cases where an observer feels troublesome to wear the glasses.

  Thus, for example, a display device that can observe a stereoscopic image with the naked eye, such as the display device disclosed in Patent Document 1, has been developed. In the display device disclosed in Patent Literature 1, left and right eye images are emitted in predetermined directions by a double-sided prism sheet provided between an LCD (Liquid Crystal Display) panel and a light guide plate. This double-sided prism sheet has a triangular prism lens array on the incident side, and a cylindrical lens array arranged in the same direction as the triangular prism lens array on the output side, and having the same pitch as the triangular prism lens array.

Japanese Patent No. 3930021

The above-mentioned double-sided prism sheet needs to maintain the accuracy of alignment between the cylindrical lens and the triangular prism and the accuracy of the shape and dimensions in order to deliver the images for the respective eyes to the left and right eyes. If the alignment accuracy, shape accuracy, and the like are low, for example, a crosstalk or the like in which a left-eye image that should originally reach the left eye also reaches the right eye occurs, and the stereoscopic image becomes unclear.
In addition, since the light emitted from such a double-sided lens sheet is emitted intermittently according to the arrangement pitch of the triangular prisms (see, for example, FIG. 7), moire may occur or the image may appear streak. . In order to reduce these, the cylindrical lens and the triangular prism lens need to be smaller than the sub-pixel of the LCD panel, and further fine pitch is required.

However, it is not easy to manufacture a double-sided lens sheet with high precision in shape and dimensions and alignment while achieving a fine pitch in the prism shape and lens shape, and due to mold molding and capital investment, etc. There was a problem that the production cost was high.
Further, in the case of the lens sheet as described above, when the fine pitch is to be achieved, it is necessary to reduce the total thickness of the lens sheet itself. In this case, distortion due to a decrease in the rigidity of the lens sheet and accompanying image distortion occur. There was a problem.

  An object of the present invention is to provide a lens sheet manufacturing method, a lens sheet, and a surface light source device including the lens sheet that can easily manufacture a lens sheet that is highly accurate in shape and the like, and is less likely to cause image distortion even when the pitch is fine. And providing a transmissive display device.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention according to claim 1 is a lens layer (141) provided with a plurality of substantially cylindrical unit lenses (144) that are provided on one surface of the substrate layer and are convex on the emission side. 145) and a prism layer (143) provided with a plurality of unit prisms (142) formed on the other surface of the base material layer and having a substantially triangular prism shape convex toward the incident side and having a curved surface with concave side surfaces. And the arrangement direction of the unit lenses and the arrangement direction of the unit prisms are parallel, and the arrangement pitch of the unit lenses and the unit prisms is the same, as viewed from the normal direction of the sheet surface, The vertex of the unit prism is a method of manufacturing a lens sheet that coincides with the vertex of the unit lens, and a lens layer forming the lens layer in which a plurality of the unit lenses are arranged on one surface of the base material layer Process and the lens A coating film forming step of forming a coating film of ionizing radiation curable resin on the surface opposite to the surface on which the surface is formed, and along a direction substantially perpendicular to the surface of the base material layer from the lens layer side An exposure process of irradiating ionizing radiation that is substantially parallel light and exposing and curing the coating film through which the ionizing radiation collected by the unit lens is transmitted, and exposing the coating film in the exposure process. And removing the uncured portion by development processing, and in the lens layer forming step, the base material layer uses a material whose thickness T satisfies 25 μm ≦ T ≦ 50 μm, The unit lens is a method for producing a lens sheet, wherein the arrangement pitch P is formed so as to satisfy 40 μm ≦ P ≦ 140 μm.

According to a second aspect of the present invention, in the lens sheet manufacturing method according to the first aspect of the present invention, a post-exposure step of irradiating ionizing radiation from the prism layer (143) side is provided after the removing step. It is a manufacturing method of a lens sheet.
According to a third aspect of the present invention, in the lens sheet manufacturing method according to the first or second aspect, the side surface of the unit prism adjacent to one of the side surfaces of the unit prism is obtained by the development processing in the removing step. The lens sheet is characterized in that the curve formed by and becomes a substantially parabolic shape or a substantially catenary curve shape in a cross section parallel to the arrangement direction of the unit prisms (142) and perpendicular to the sheet surface. is there.
According to a fourth aspect of the present invention, in the lens sheet manufacturing method according to any one of the first to third aspects, the lens layer forming step includes a molding die (305) that shapes the shape of the unit lens. ) Is coated with an ionizing radiation curable resin, the substrate layer (141) is pressed against the mold, and the ionizing radiation curable resin is cured by irradiating with ionizing radiation to transfer the shape of the unit lens. The method for producing a lens sheet is characterized in that the base material layer integrated with the ionizing radiation curable resin to which the shape of the unit lens is transferred is peeled off from the mold.

The invention of claim 5 is a lens sheet (14) produced by the method for producing a lens sheet according to any one of claims 1 to 4.
According to a sixth aspect of the present invention, a transmissive display unit of a transmissive display device capable of displaying a stereoscopic image by alternately emitting right-eye video light and left-eye video light in predetermined directions is irradiated from the back side. And a base layer (141) and a substantially cylindrical unit lens (144) provided on the exit side surface of the base layer and convex on the exit side. A plurality of arranged lens layers (145) and a plurality of unit prisms (142) which are provided on the incident side surface of the base material layer and have a substantially triangular prism shape convex toward the incident side and having a curved surface with concave side surfaces. An arrangement prism layer (143), the arrangement direction of the unit lenses and the arrangement direction of the unit prisms are parallel, and the arrangement pitch of the unit lenses and the unit prisms is the same, Seen from the normal direction, The apex of the displacement prism coincides with the apex of the unit lens, the thickness T of the base material layer satisfies 25 μm ≦ T ≦ 50 μm, and the arrangement pitch P of the unit lens and the unit prism is 40 μm ≦ A lens sheet (14) characterized by satisfying P ≦ 140 μm.

According to a seventh aspect of the present invention, in the lens sheet according to the fifth or sixth aspect, the vertex (142t) of the unit prism (142) is along the normal direction of the sheet surface from the unit lens (144) side. The lens sheet (14) is located on the unit lens side in the thickness direction of the lens sheet with respect to the focal position (f) of the substantially parallel light when irradiated with substantially parallel light.
The invention according to claim 8 is the lens sheet according to any one of claims 5 to 7, wherein the side surface of the unit prism adjacent to one side surface (142b) of the unit prism (142). (142a) is a lens sheet (14) characterized in that a curve formed in a cross section parallel to the arrangement direction of the unit prisms and orthogonal to the sheet surface is a substantially parabolic shape or a substantially catenary curve shape. It is.

The invention according to claim 9 is the lens sheet (14) according to any one of claims 5 to 8, a light guide plate (13) disposed on an incident side of the lens sheet, and the unit lens. (144) and the first light source unit (12A) and the first light source unit (12A) which are arranged on the two end faces (13a, 13b) of the light guide plate and which face each other in the arrangement direction of the unit prisms (142) and alternately repeat light emission and extinction. A surface light source device (12A, 12B, 13, 14).
A tenth aspect of the present invention is the surface light source device (12A, 12B, 13, 14) according to the ninth aspect, and a right eye image and a left eye image that are irradiated from the back side by the surface light source device and have parallax. And a transmissive display section (11) that alternately displays the right-eye image when the first light source section (12A) emits light, When the second light source unit (12B) emits light, the left eye image is displayed, and the display image is switched in synchronization with the light emission of the first light source unit and the second light source unit. A transmissive display device (10) characterized in that a stereoscopic image can be displayed.

According to the present invention, the following effects can be obtained.
(1) The method for producing a lens sheet according to the present invention includes a lens layer forming step of forming a lens layer in which a plurality of unit lenses are arranged on one surface of a base material layer, and a surface on which the lens layer of the base material layer is formed. Coating film forming step of forming a coating film of ionizing radiation curable resin on the opposite surface, and ionizing radiation that is substantially parallel light along a direction substantially perpendicular to the surface of the base material layer from the lens layer side And exposing the coating film where the ionizing radiation condensed by the unit lens is transmitted and curing, and developing the uncured part of the coating film that was not exposed in the exposure process In the lens layer forming step, the base material layer has a thickness T satisfying 25 μm ≦ T ≦ 50 μm, and the unit lenses have an arrangement pitch P of 40 μm ≦ P ≦ 140 μm. Shall be formed to satisfy .
Thereby, the unit lens and the unit prism can be easily aligned with high accuracy, and a lens sheet with a finer pitch can be easily manufactured. In addition, a mold for shaping the shape of the unit prism becomes unnecessary, and the production cost can be reduced. Further, when used in a surface light source device of a transmissive display device capable of displaying a stereoscopic image, crosstalk (for example, a phenomenon in which video light for the right eye that should originally reach the right eye reaches the left eye) is reduced or bent. Thus, it is possible to easily manufacture a lens sheet that is effective in reducing deformation.

(2) Since the lens sheet manufacturing method includes a post-exposure step of irradiating ionizing radiation from the prism layer side after the removing step, the uncured portion can be reliably cured.

(3) In the lens sheet manufacturing method, a cross section in which a curve formed by one side surface of a unit prism and a side surface of an adjacent unit prism is parallel to the arrangement direction of the unit prisms and is orthogonal to the sheet surface by development processing. , The shape of the unit prism can be controlled by development processing.

(4) The lens sheet manufacturing method is such that, in the lens layer forming step, an ionizing radiation curable resin is applied to a molding die for shaping the shape of the unit lens, the substrate layer is pressed against the molding die, and the ionizing radiation is irradiated. Then, the ionizing radiation curable resin is cured to transfer the shape of the unit lens, and the base material layer integrated with the ionizing radiation curable resin to which the shape of the unit lens is transferred is peeled off from the molding die. Can be easily manufactured. In addition, the arrangement pitch of the unit lenses can be made finer while maintaining a high transfer rate of the shape of the unit lenses.

(5) Since the lens sheet is produced by the lens sheet manufacturing method according to the present invention, the position of the unit lens and the unit prism is not shifted, and the shape accuracy can be high.

(6) The lens sheet according to the present invention includes a base material layer, a lens layer provided on a surface on the emission side of the base material layer, in which a plurality of substantially cylindrical unit lenses are arranged, and a surface on the incident side of the base material layer. A prism layer in which a plurality of unit prisms each having a substantially triangular prism shape and having a concave side surface are arranged, and the unit lens arrangement direction and the unit prism arrangement direction are parallel to each other, and the unit lens and the unit prism Are arranged at the same pitch, and the vertex of the unit prism coincides with the vertex of the unit lens when viewed from the normal direction of the sheet surface, and the thickness T of the base layer satisfies 25 μm ≦ T ≦ 50 μm. The arrangement pitch P of the unit lenses and the unit prisms satisfies 40 μm ≦ P ≦ 140 μm.
Accordingly, since the side surface of the unit prism is a curved surface that is concave on the incident side, even when the accuracy of the shape and dimensions near the apex of the unit prism is not so high, light can be launched to the viewer side. .
Also, when this lens sheet is used for a surface light source device of a transmissive display device capable of displaying a stereoscopic image, right eye image light and left eye image light are alternately emitted in a predetermined direction. The image light for the right eye can be delivered to the right eye, and the image light for the left eye can be delivered to the left eye. Therefore, a good stereoscopic image can be provided to the observer. Furthermore, by using this lens sheet, it is possible to reduce image distortion due to bending and to display a good image.

(7) The unit lens has a vertex in the thickness direction of the lens sheet, rather than the focal position of the substantially parallel light when the substantially parallel light is irradiated along the normal direction of the sheet surface from the unit lens side. Therefore, the light incident on the unit prism can be efficiently raised to the emission side and emitted in a predetermined direction.

(8) A curve formed in a cross section in which one side surface of the unit prism and a side surface of the adjacent unit prism are parallel to the arrangement direction of the unit prisms and orthogonal to the sheet surface is a substantially parabolic shape or a substantially catenary curve shape. Therefore, the light incident on the unit prism can be efficiently launched to the emission side.

(9) The lens sheet of the present invention, the light guide plate arranged on the incident side of the lens sheet, and the two end faces of the light guide plate facing each other in the arrangement direction of the unit lenses and the unit prisms, and alternately emitting light and Since the surface light source device includes the first light source unit and the second light source unit that are repeatedly turned off, light can be emitted alternately in a predetermined direction.

(10) A surface light source device according to the present invention, and a transmissive display unit that alternately displays a right-eye image and a left-eye image that are irradiated from the back side by the surface light source device and have parallax, The unit displays an image for the right eye when the first light source unit emits light, and displays an image for the left eye when the second light source unit emits light. Since this is a transmissive display device capable of displaying a stereoscopic image by switching the display image in synchronization with the light emission of the second light source unit, the observer can control the viewing of the left and right eye images. Good 3D images can be displayed without using. In addition, image distortion due to bending can be reduced, and a good image can be displayed.

It is a figure explaining the display apparatus of embodiment. It is a figure which expands and shows a part of cross section of the lens sheet of embodiment. It is a figure which shows the mode of the light which injects into the lens sheet of embodiment. It is a figure which shows an example of the manufacturing apparatus of the lens sheet of embodiment. It is a figure explaining the manufacturing method of the lens sheet of an embodiment. It is a figure which shows the difference in the shape of a unit prism by the thickness of a base material layer. It is a figure which shows the mode of the light which injects into the conventional lens sheet.

Embodiments of the present invention will be described below with reference to the drawings.
In addition, each figure shown below including FIG. 1 is the figure shown typically, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.
In addition, the terms “plate”, “sheet”, “film” and the like are used, but these are generally used in the order of thickness, “plate”, “sheet”, “film”. I am using it. However, since there is no technical meaning in such proper use, the description in the claims is used in the unified description of the sheet. Accordingly, the terms “sheet”, “plate”, and “film” can be appropriately replaced. For example, the optical sheet may be an optical film or an optical plate.
Furthermore, numerical values such as dimensions and material names of each member described in the present specification are examples of the embodiment, and the present invention is not limited thereto, and may be appropriately selected and used.

(Embodiment)
FIG. 1 is a diagram illustrating a display device 10 according to the present embodiment.
The display device 10 includes an LCD panel 11, light source units 12A and 12B, a light guide plate 13, a lens sheet 14, and a control unit 15, and illuminates and displays an image displayed on the LCD panel 11 from the back. It is a transmissive liquid crystal display device, and is a stereoscopic image display device that allows the observer O to observe stereoscopic images without using stereoscopic glasses or the like. The surface light source device (backlight) in the display device 10 is an edge ride type, and corresponds to the light source units 12A and 12B, the light guide plate 13, and the lens sheet 14.

  The LCD panel 11 is a transmissive display unit including a transmissive liquid crystal display element. The LCD panel 11 of the present embodiment has a substantially rectangular shape with a screen size of 2.8 inches diagonal, and can display a resolution of 320 × 240 pixels. The LCD panel 11 has a plurality of sub-pixels arranged in a matrix. Each of the sub-pixels displays primary colors of red (R), G (green), and blue (B), and three sub-pixels of R, G, and B constitute one pixel as a set. In the present embodiment, one pixel has a substantially square shape and is arranged in the horizontal direction of the screen and the vertical direction of the screen. One pixel is divided into three in the horizontal direction of the screen, and R, G, and B subpixels are arranged. The arrangement pitch of the pixels is about 178 μm, and the arrangement pitch of the sub-pixels in the horizontal direction of the screen is about 59 μm. Note that the present invention is not limited to the above example, and one pixel may be composed of three or more subpixels.

In the following specification, as an example, the direction parallel to the short side of the observation screen (LCD panel 11) in the usage state of the display device 10 is the screen vertical direction (screen vertical direction) in the usage state, and is parallel to the long side. The direction is the left-right direction of the screen in the use state (the horizontal direction of the screen). FIG. 1 shows a cross-sectional state parallel to the left-right direction of the screen of the display device 10. In the following description, unless otherwise specified, it is assumed that the screen horizontal direction and the screen vertical direction are the screen horizontal direction and the screen vertical direction when the display device 10 is used.
The LCD panel 11 alternately displays a right-eye image and a left-eye image having parallax according to an instruction from the control unit 15.

The light source units 12 </ b> A and 12 </ b> B are light source units that emit light that illuminates the LCD panel 11. The light source parts 12A and 12B are provided at positions facing both end faces 13a and 13b of the light guide plate 13 in the horizontal direction of the screen. The light source units 12A and 12B are alternately turned on and off in response to an instruction from the control unit 15. The light emission and extinction of the light source units 12A and 12B are synchronized with the switching of the display image on the LCD panel 11.
The light source units 12A and 12B according to the present embodiment use a light emitting diode (LED) that emits white light as a light source, and extend in the vertical direction of the screen along both horizontal ends of the light guide plate 13 (not shown). Used in combination with a guide.

The light guide plate 13 is a member that guides light emitted from the light source units 12A and 12B. As shown in FIG. 1, light source sections 12 </ b> A and 12 </ b> B are arranged at positions facing the two end faces 13 a and 13 b of the light guide plate 13 facing each other in the arrangement direction of the unit lenses 144 and the unit prisms 142.
The light guide plate 13 of the present embodiment is made of an acrylic resin, but is not limited thereto, and for example, a PC (polycarbonate) resin or the like may be appropriately selected and used.
The light guide plate 13 has dots (not shown) formed on its back surface 13d by printing or the like. Further, the surface 13c on the exit side of the light guide plate 13 may be roughened. Further, a reflection plate (not shown) or the like may be provided on the back side of the light guide plate 13 (the side opposite to the lens sheet 14).

The lens sheet 14 includes a base material layer 141, a prism layer 143 in which a plurality of unit prisms 142 are arranged on the incident side (light guide plate 13 side) surface of the base material layer 141, and the output side (LCD panel) of the base material layer 141. 11 side) and a lens layer 145 in which a plurality of unit lenses 144 are arranged.
The lens sheet 14 emits light incident on the unit prism 142 on the incident side (light guide plate 13 side) in a direction that reaches the left and right eyes of the observer O located in the substantially front direction from the unit lens 144. The lens sheet 14 according to the present embodiment controls the direction of light emitted from the light guide plate 13 and is viewed from an observer O positioned substantially in front of the observation surface of the display device 10 (the sheet surface of the lens sheet 14). The light that reaches the right eye of the observer O is emitted in a direction that forms about 0 to 15 ° on the right side of the screen in the left-right direction with respect to the normal direction of the sheet surface, and the light that reaches the left eye is normal to the sheet surface. The light is emitted in a direction of about 0 to 15 ° on the left side in the horizontal direction of the screen with respect to the line direction.

FIG. 2 is an enlarged view showing a part of a cross section of the lens sheet 14 of the present embodiment. In FIG. 2, a cross section orthogonal to the sheet surface of the lens sheet 14 and parallel to the arrangement direction of the unit prism 142 and the unit lens 144 (horizontal direction of the screen) is shown.
The sheet surface indicates, for example, a surface of the lens sheet 14 that is the planar direction of the lens sheet 14 when viewed as the entire lens sheet 14, and in the present specification and claims. Are also used as the same definition. Further, the sheet surface of the lens sheet 14 is parallel to the observation surface of the display device 10 (LCD panel 11).
The base material layer 141 is a layer that becomes a base material (base) of the lens sheet 14. As the base material layer 141, a sheet-like member made of a thermoplastic resin having light transmittance is used, and its thickness is T. The thickness T of the base material layer satisfies 25 μm ≦ T ≦ 50 μm.

The prism layer 143 is formed on the surface on the incident side (light guide plate 13 side) of the base material layer 141, and a plurality of unit prisms 142 are provided on the incident side surface in one direction (the screen left-right direction) along the sheet surface. It is arranged.
The unit prism 142 has a substantially isosceles triangular prism shape, but the side surfaces 142a and 142b are concave curved surfaces. In the cross section shown in FIG. 2, a curve connecting the vertices 142t of two adjacent unit prisms 142 (that is, in the cross section shown in FIG. 2, the side surface 142a of the unit prism 142 and the unit prism adjacent to the unit prism 142). The curve formed by the side surface 142b has a substantially parabolic shape that is concave with respect to the light guide plate 13 side.

The vertex 142t of the unit prism is located closer to the base material layer 141 than the virtual focal point f of the unit lens 144 in the thickness direction of the lens sheet 14 (the normal direction of the sheet surface). The focal point f is a state in which the incident side of the base material layer 141 is covered with a resin that forms the unit prism 142 with a sufficient thickness, and substantially parallel light is irradiated from the unit lens 144 side in a direction orthogonal to the sheet surface. This is a point that becomes the focal point (condensing point) of the substantially parallel light.
The unit prism 142 (prism layer 143) of this embodiment is made of an ultraviolet curable resin. The unit lens 144 is not limited to the ultraviolet curable resin, and may be formed using other ionizing radiation curable resin such as an electron beam curable resin.
Further, the arrangement pitch of the unit prisms 142 is P. This arrangement pitch P satisfies 40 μm ≦ P ≦ 140 μm.
Further, the unit prism 142 has a dimension h1 from the incident surface of the base material layer 141 to the apex 142t in the thickness direction, and the height of the unit prism 142 (thickness direction from the point v1 serving as a valley bottom between the unit prisms 142 to the apex 142t). ) Is h2, and the land thickness is d1 (d1 = h1-h2).

The lens layer 145 is formed on the surface of the base material layer 141 on the emission side (LCD panel 11 side). On the surface of the lens layer 145, along the sheet surface, the unit lens 144 is parallel to the arrangement direction of the unit prisms 142 (right and left of the screen). In the direction).
The unit lens 144 is a substantially cylindrical lens, and is a so-called cylindrical lens.
The arrangement pitch of the unit lenses 144 is P, which is equal to the arrangement pitch of the unit prisms 142. When viewed from the normal direction of the sheet surface, one unit lens 144 corresponds to one unit prism 142 via the base material layer 141, passes through the vertex 144t of the unit lens 144, and is orthogonal to the sheet surface. A straight line (virtual straight line H indicated by a broken line in FIG. 2) passes through the vertex 142t of the unit prism 142, and the positions of the vertex 142t and the vertex 144t coincide with each other when viewed from the normal direction of the sheet surface.

The radius of curvature of the unit lens 144 is R, the dimension from the surface on the emission side of the base material layer 141 in the thickness direction to the apex 144t of the lens is h3, the lens height of the unit lens 144 (the valley bottom between the unit lenses 144 and The normal dimension of the sheet surface from the point v2 to the vertex 144t of the lens) is h4, and the land thickness is d2 (d2 = h3−h4).
The unit lens 144 (lens layer 145) of this embodiment is made of an ultraviolet curable resin. The unit lens 144 is not limited to the ultraviolet curable resin, and may be formed using other ionizing radiation curable resin such as an electron beam curable resin.

FIG. 3 is a diagram illustrating a state of light rays incident on the lens sheet of the embodiment. FIG. 3 shows the state of light incident from 75 degrees with respect to the normal direction of the sheet surface.
By using the lens sheet 14 as described above, for example, light incident on the curved side surface 142b is totally reflected by the curved side surface 142a and is emitted from the unit lens 144. At this time, as shown in FIG. 3, the lens sheet 14 divides into a plurality of light beams from one unit lens 144 in a predetermined angle direction on the observer O side, and spreads out within a predetermined emission angle. The interval between the luminous fluxes is narrower than that of the conventional lens sheet 54 shown in FIG. Further, in the conventional lens sheet 54 shown in FIG. 7, the light emitted to the viewer side enters the vicinity of the apex of the unit prism 542 having a triangular cross section, and is totally reflected by the facing surface. However, in the lens sheet 14 of the embodiment, not only the vicinity of the top of the unit prism 142 but also the light incident at a position slightly away from the apex t is totally reflected on the valley side of the unit prism 142 on the side surface facing the observer O. Raised to the side and emitted.
Therefore, by using the lens sheet 14 of the present embodiment for the display device 10, it is possible to reduce the muscular feeling and moire of the image and display a clear stereoscopic image. In addition, even if the forming accuracy of the unit prism 142 (accuracy of the shape and size of the manufactured unit prism with respect to the design shape), in particular, the accuracy of the shape in the vicinity of the apex 142t is somewhat low, the observer O positioned substantially in the front direction. Light can be emitted to the side, and manufacturing becomes easy.

The dimension of each part of the lens sheet which is an example of the lens sheet 14 of this embodiment is as follows. Unit prism 142 and unit lens 144 arrangement pitch P = 40 μm, base material layer 141 thickness T = 38 μm, unit prism 142 apex 142t to base material layer 141 incident side surface h1 = 24 μm, unit prism 142 height h2 = 20 μm, land thickness d1 = 4 μm, unit lens radius of curvature R = 29 μm, dimension h3 = 12 μm from the apex 144t of the unit lens 144 to the exit side surface of the base layer 141, unit lens 144 Height h4 = 8 μm and land thickness d2 = 4 μm. In the cross section shown in FIG. 3, the curve formed by the concave shape formed by the side surfaces of the unit prisms 142 adjacent to each other has the horizontal direction of the screen as the x-axis direction and the normal direction of the sheet surface as the y-axis. Along the normal direction of the surface, when the observer O side is the y-axis plus side and the point v1 that is the valley bottom is the origin, it is approximately approximated to a parabola of y = −0.05 × ² .
Further, the refractive indexes of the unit lens 144, the base material layer 141, and the unit prism 142 are all 1.55. The base material layer 141 is made of PET resin.
A method for manufacturing the lens sheet 14 will be described later.

Returning to FIG. 1, the control unit 15 alternately switches the light emission of the light source units 12 </ b> A, 12 </ b> B, and synchronizes with the light emission of the light source units 12 </ b> A, 12 </ b> B. Instructs to switch to the video. That is, according to an instruction from the control unit 15, for example, when the light source unit 12B is turned off and the light source unit 12A emits light, the LCD panel 11 displays an image for the right eye, and the light source unit 12A is turned off and the light source unit 12B emits light. When this is done, the LCD panel 11 displays the image for the left eye.
The control unit 15 of this embodiment instructs the switching of the display image on the LCD panel 11 and the alternate light emission of the light source units 12A and 12B while synchronizing at a predetermined frequency. This frequency may be appropriately set according to the characteristics of the LCD panel 11 to be used, the usage environment, and the like.

A method for displaying a stereoscopic image of the display device 10 according to the present embodiment will be described.
In the display device 10 illustrated in FIG. 1, for example, the light emitted from the light source unit 12 </ b> A is guided through the light guide plate 13 and is emitted from the exit-side surface 13 c of the light guide plate 13. Is incident on the side surface 142a. The light incident on the unit prism 142 is totally reflected by the side surface 142b facing the side surface 142a and travels toward the unit lens 144 side. Then, the direction from the unit lens 144 toward the right eye side of the observer O positioned substantially in the front direction (viewed from the observer O, about 0 to 15 ° in the horizontal direction of the screen with respect to the normal direction of the observation surface of the display device 10). Exits to the right) and enters the LCD panel 11. At this time, since the LCD panel 11 displays the right-eye image, the light of the right-eye image reaches the right eye of the observer O. On the other hand, since the light source unit 12B is turned off, the amount of light reaching the left eye is very small and does not affect the viewing of the stereoscopic video.

The light emitted from the light source unit 12 </ b> B is guided through the light guide plate 13, exits from the exit-side surface 13 c of the light guide plate 13, and enters one side 142 b of the unit prism 142 of the lens sheet 14. The incident light is totally reflected by the opposing side surface 142a and travels toward the unit lens 144 side. Then, the direction toward the left eye of the observer O positioned substantially in the front direction from the unit lens 144 (viewed from the observer O is about 0 to 15 ° in the horizontal direction of the screen with respect to the normal direction of the observation surface of the display device 10. Exits to the left) and enters the LCD panel 11. At this time, since the LCD panel 11 displays the left-eye image, the light of the left-eye image reaches the left eye of the observer O. On the other hand, since the light source unit 12A is turned off, the amount of light reaching the right eye is very small and does not affect the viewing of the stereoscopic video.
Therefore, the right eye image reaches the right eye of the observer O, the left eye image reaches the left eye, and these are switched at high speed, so that the observer O recognizes it as a stereoscopic image.

(Lens sheet manufacturing method)
Here, the manufacturing method of the lens sheet 14 of this embodiment is demonstrated.
FIG. 4 is a diagram illustrating an example of a manufacturing apparatus for the lens sheet 14 according to the present embodiment.
FIG. 5 is a diagram illustrating a method for manufacturing the lens sheet 14 of the present embodiment.
The lens sheet manufacturing apparatus 300 includes a lens layer forming unit 301 and a prism layer forming unit 302, as shown in FIG.
The lens layer forming unit 301 includes a first application unit 303, a pressing roll 304, a molding roll 305, a first light source unit 306, and a release roll 307. The 1st application part 303 is a dispenser which supplies ultraviolet curable resin. The pressing roll 304, the forming roll 305, and the release roll 307 are all substantially cylindrical members, and are members that can be rotationally driven with the central axis as a rotation axis. The pressing roll 304 is a member that presses the base material layer 141 unwound from the original fabric roll 141A toward the molding roll 305 side. The molding roll 305 is a molding die for shaping the shape of the unit lens 144, and a mold shape (not shown) for shaping the unit lens 144 is arranged on the outer peripheral surface thereof in the axial direction of the molding roll. . The direction in which the mold shapes are arranged may be arranged in the circumferential direction of the forming roll 305. The release roll 307 is a member that releases the base material layer 141 from the molding roll 305. The first light source unit 306 is a light source device that irradiates ultraviolet rays.

  The prism layer forming unit 302 includes a second application unit 308, a second light source unit 309, a developing device 310, a third light source unit 311, and the like. The second application unit 308 applies a UV curable resin to the surface of the base material layer 141 opposite to the surface on which the lens layer 145 is formed to form a coating film 143R (see FIG. 5B). It is. The second light source unit 309 is a light source device that irradiates substantially parallel light along a direction orthogonal to the surface of the base material layer 141 (the sheet surface of the lens sheet). The developing device 310 is a device that removes the coating film of the uncured portion. The third light source unit 311 is a light source device that irradiates ultraviolet rays from the prism layer 143 side.

First, in the manufacturing apparatus 300, the base material layer 141 is unwound from the original fabric roll 141 </ b> A around which the base material layer 141 is wound, by the roll 312, and is conveyed to the lens layer forming unit 301.
In the lens layer forming unit 301, the base material layer 141 is supplied between the pressing roll 304 and the molding roll 305 with one side (the surface 141 b shown in FIG. 5A) side as the molding roll 305 side. At this time, the UV curable resin is supplied from the first application unit 303 to the molding roll 305, and the base material layer 141 sandwiches the supplied UV curable resin between the molding roll 305 and the base material layer 141. It passes between the pressing roll 304 and the molding roll 305 in a state. At this time, the base material layer 141 is pressed toward the molding roll 305 by the pressing roll 304. As shown in FIG. 4, the ultraviolet curable resin may be supplied to the mold shape of the molding roll 305 or may be applied to the surface of the base material layer 141. As shown in FIG. 4, it is possible to prevent air bubbles from entering by applying an ultraviolet curable resin reservoir in the valley between the molding roll 305 and the pressing roll 304.

Next, in a state where the base material layer 141 is wound around the molding roll 305, the first light source unit 306 is irradiated with ultraviolet light to cure the ultraviolet curable resin between the base material layer 141 and the molding roll 305, thereby The shape of the unit lens 144 is transferred to a curable resin layer (lens layer).
Next, the base material layer 141 proceeds to the release roll 307 located on the opposite side of the pressing roll 304 with the molding roll 305 interposed therebetween, and the base layer on which the lens layer 145 is formed from the molding roll 305 by the release roll 307. Layer 141 is peeled off.
Thereby, a lens layer 145 having a unit lens as shown in FIG. 5A is formed on one surface of the base material layer 141 (lens layer forming step).

Next, the base material layer 141 on which the lens layer 145 is formed is conveyed to the prism layer forming unit 302. Then, an ultraviolet curable resin is applied to the surface opposite to the surface on which the lens layer 145 of the base material layer 141 is formed (the surface 141a shown in FIG. 5) by the second application unit 308, and FIG. A coating film 143R as shown in FIG.
Next, the second light source unit 309 irradiates ultraviolet light that is substantially parallel light along the normal direction of the surface (sheet surface) of the base material layer 141 from the lens layer 145 side. Thereby, as shown in FIG.5 (c), the part which the light (ultraviolet ray) condensed by the unit lens 144 permeate | transmits among the coating films 143R is UV-exposed and hardened (exposure process). At this time, an unexposed portion (portion through which ultraviolet rays do not transmit) of the coating film 143R remains uncured.

Next, the base material layer 141 is conveyed to the developing device 310. In the developing device 310, for example, an unexposed portion of the coating film 143R is removed by WET development (wet development) using a mixed solution of isopropyl alcohol (IPA) and ethyl acetate as a developer (removal step). By this development processing, side surfaces 142a and 142b of the unit prism 142 that are concave curved surfaces are formed.
Next, ultraviolet light is irradiated from the prism layer 143 side by the third light source unit 311 to perform post UV exposure (post exposure process). As a result, the unit prism 142 (prism layer 143) is substantially completely cured. This post-UV exposure may be performed from the unit lens 144 side.
Thereafter, the base material layer 141 on which the prism layer 143 and the lens layer 145 are formed is wound around a winding roll 141B, for example, as shown in FIG. 4, and is cut into a predetermined size by a cutting device (not shown). A lens sheet 14 as shown in FIG. 5D is completed. The base material layer 141 on which the prism layer 143 and the lens layer 145 are formed is not taken up by the take-up roll 141B as shown in FIG. Good.

By manufacturing the lens sheet 14 of the present embodiment by the manufacturing method as described above, the alignment between the unit lens 144 and the unit prism 142 can be reliably performed with high accuracy, and a complicated alignment process is performed. Is also unnecessary and can be easily manufactured.
Further, by selecting such a manufacturing method, even in a lens sheet including unit prisms 142 and unit lenses 144 that have an arrangement pitch P of around 40 μm, the accuracy of the shape and dimensions of the unit prisms and the like is high. In addition, a device with high alignment accuracy can be easily manufactured. Note that even a lens sheet having an arrangement pitch P of unit prisms 142 and unit lenses 144 of about 150 to 200 μm can be manufactured with high accuracy.
Furthermore, by using such a manufacturing method, a mold for shaping the shape of the unit prism becomes unnecessary, and the production cost can be reduced.

Here, since the lens sheet 14 of the present embodiment is manufactured by the manufacturing method as described above, since the focal position f is also constant when the shape and the arrangement pitch P of the unit lenses 144 are constant, the unit prism The shape of 142 depends on the thickness of the base material layer 141.
FIG. 6 is a diagram showing the difference in the shape of the unit prism depending on the thickness of the base material layer. The lens sheets shown in FIGS. 6A to 6C have substantially the same shape except that the thickness of the base material layer 141 and the shape of the prism layer 143 are different, and the apex of the unit prism 142 from the apex of the unit lens 144. The dimensions up to are substantially the same. The thickness of the base material layer 141 of the lens sheet shown in FIGS. 6A to 6C satisfies the relationship T1 <T2 <T3. The lens sheet shown in FIG. 6A corresponds to the lens sheet of this embodiment.
As shown in FIG. 6, when the shape of the unit lens 144 is constant and the thickness of the base material layer 141 is increased, the land thickness of the unit prism 142 is decreased. If the base material layer 141 is too thick, the surface of the base material layer 141 is exposed between the unit prisms 142 and the side surfaces 142a and 142b of the unit prism 142 are formed as shown in FIG. The curved surface is not formed.

  In the lens sheet shown in FIG. 6A in which the preferred shape of the unit prism 142 is obtained, the light L1 that is incident near the approximate apex of the unit prism 142 or a position that is slightly away from the apex compared to the light L1. All of the lights L2 are launched to the observer O side. However, in the lens sheet having the substrate layer 141 that is too thick as shown in FIG. 6C, a part of the light L3 incident in the vicinity of the approximate apex 142t rises toward the observer O, but is slightly smaller than the light L3. The light L4 incident at a position away from the apex 142t does not travel toward the unit lens 144 corresponding to the light incident on the unit prism 142, but travels in a direction greatly deviated from the observer O side. Moreover, the amount of light L4 is larger than the amount of light L3. For this reason, when such a lens sheet is used for the display device 10, the stereoscopic image becomes unclear and difficult to observe, or the brightness of the image becomes dark.

  Moreover, when the base material layer 141 is made thin, a preferable shape of the unit prism 142 can be obtained, but there is a problem that the rigidity as a lens sheet is lowered and bending or distortion is likely to occur. When the arrangement pitch P of the unit lenses 144 and the unit prisms 142 is set to 140 μm or less and a fine pitch is to be obtained, in order to obtain a preferable shape of the unit prisms 142, the base material layer is compared with a lens sheet having P = about 150 to 200 μm. It is necessary to make the thickness T of 141 thinner. However, by reducing the thickness T of the base material layer 141, deformation such as bending is more likely to occur. Such deformation of the lens sheet, such as bending, is observed as image distortion (image distortion) when used in a display device, and greatly affects image quality.

Further, the unit lenses 144 and the unit prisms 142 are strongly required to have fine pitches from the viewpoints of clarifying stereoscopic images and improving image quality.
From the above, in this embodiment, the arrangement pitch P of the unit lenses 144 and the unit prisms 142 satisfies 40 μm ≦ P ≦ 140 μm, and the thickness T of the base material layer 141 satisfies 25 μm ≦ T ≦ 50 μm. It was supposed to be. From the viewpoint of displaying a clear stereoscopic image and further improving the effect of reducing display defects such as image streaks and moire, the arrangement pitch P of the unit lenses 144 and the unit prisms 142 is determined in the horizontal direction of the subpixel. More preferably, it is smaller than the arrangement pitch.

(Comparison between the lens sheet of the example and the lens sheet of the comparative example)
Here, the lens sheet 14 of the example of this embodiment and the lens sheet of the comparative example were prepared, and the clarity of the stereoscopic image of the display device using these and the presence or absence of occurrence of image distortion were examined.
The lens sheet of the comparative example has substantially the same form as the lens sheet 14 of the example except that the arrangement pitch P and the thickness T of the base material layer are different.
The dimensions of the unit prism and unit lens arrangement pitch P and base layer thickness T of the lens sheet of the example and the lens sheet of the comparative example are as follows. In the lens sheets of the examples and comparative examples, the lens layer, the base material layer, and the prism layer all have a refractive index of 1.55. Further, the base material layer is made of PET resin, and the lens layer and the prism layer are made of ultraviolet curable resin.
Furthermore, the exposure conditions and development conditions of the lens sheets of these examples and comparative examples are the same.
The lens sheet of Comparative Example 1 has unit lens arrangement pitch P = 140 μm and base layer thickness T = 100 μm.
The lens sheet of Comparative Example 2 has unit lens arrangement pitch P = 140 μm and base layer thickness T = 75 μm.
The lens sheet of Example 1 has unit lens arrangement pitch P = 140 μm and base layer thickness T = 50 μm.
The lens sheet of Example 2 has unit lens array pitch P = 140 μm and base layer thickness T = 38 μm.
Example 3 The lens sheet has a unit lens arrangement pitch P = 140 μm and a base material layer thickness T = 25 μm.
The lens sheet of Comparative Example 3 has unit lens array pitch P = 140 μm and base layer thickness T = 12 μm.

The lens sheet of Comparative Example 4 has unit lens arrangement pitch P = 70 μm and base layer thickness T = 100 μm.
The lens sheet of Comparative Example 5 has unit lens arrangement pitch P = 70 μm and base layer thickness T = 75 μm.
The lens sheet of Example 4 has a unit lens arrangement pitch P = 70 μm and a base layer thickness T = 50 μm.
The lens sheet of Example 5 has unit lens array pitch P = 70 μm and base layer thickness T = 38 μm.
The lens sheet of Example 6 has unit lens arrangement pitch P = 70 μm and base layer thickness T = 25 μm.
The lens sheet of Comparative Example 6 has unit lens arrangement pitch P = 70 μm and base layer thickness T = 12 μm.

The lens sheet of Comparative Example 7 has unit lens arrangement pitch P = 40 μm and base layer thickness T = 100 μm.
The lens sheet of Comparative Example 8 has unit lens arrangement pitch P = 40 μm and base layer thickness T = 75 μm.
The lens sheet of Example 7 has unit lens array pitch P = 40 μm and base layer thickness T = 50 μm.
The lens sheet of Example 8 has unit lens arrangement pitch P = 40 μm and base layer thickness T = 38 μm.
The lens sheet of Example 9 has unit lens array pitch P = 40 μm and base layer thickness T = 25 μm.
The lens sheet of Comparative Example 9 has unit lens arrangement pitch P = 40 μm and base layer thickness T = 12 μm.
In addition, the lens sheets of the examples and comparative examples having the same arrangement pitch P have the same radius of curvature R of the unit lenses.

For the evaluation of the stereoscopic image, the lens sheet of each example and the optical sheet of the comparative example are incorporated in a display device similar to the display device 10 described above to display an image that can be stereoscopically displayed, and 30 cm from the observation surface in the front direction of the screen. The stereoscopic images displayed from a distant position were observed, and the clarity and visibility of the stereoscopic images were evaluated. Those in which very good 3D images are observed are marked as 表 in Table 1, and those in which good 3D images are observed are indicated by ○ in Table 1, and the 3D images are not visible or unclear. Some things are indicated as “impossible” in Table 1.
The image distortion is evaluated by incorporating the lens sheet of each example and the optical sheet of the comparative example into a display device similar to the display device 10 described above, displaying an image in a normal temperature and humidity environment, and bending or warping of the lens sheet. It was evaluated by observing whether or not the image was distorted due to the deformation of. Those in which image distortion is not observed are shown as ◯ in Table 1 as good, and those in which image distortion is slightly occurring but within the allowable range are shown as △ in Table 1, and image distortion is visually recognized. Inappropriate items are shown as x in Table 1.

As shown in Table 1, each of the display devices using the lens sheets of Examples 1 to 9 satisfying 40 μm ≦ P ≦ 140 μm and 25 μm ≦ T ≦ 50 μm has no image distortion and a stereoscopic image is clear. There was a good image.
However, although satisfying 40 μm ≦ P ≦ 140 μm, T> 50 μm, the lens sheet of Comparative Example 4 (P = 70 μm, T = 100 μm) and the lens sheet of Comparative Example 7 (P = 40 μm, T = 100 μm) In the display device using the lens sheet of Comparative Example 8 (P = 40 μm, T = 75 μm), image distortion was not observed, but the stereoscopic image was unclear and unsuitable for use.
Furthermore, the lens sheet of Comparative Example 6 (P = 70 μm, T = 12 μm) satisfying 40 μm ≦ P ≦ 140 μm but T <25 μm, and the lens sheet of Comparative Example 9 (P = 40 μm, T = 12 μm). In the display device used, the stereoscopic image was good, but the image distortion was severe, and since the substrate layer itself was thin, it was very difficult to produce and was not suitable for use.

  The lens sheet of Comparative Example 1 (P = 140 μm, T = 100 μm), the lens sheet of Comparative Example 2 (P = 140 μm, T = 75 μm), and the lens sheet of Comparative Example 5 (P = 70 μm, T = 75 μm). In each of the display devices used, each lens sheet did not satisfy the preferable range of the thickness T of the base material layer, but the stereoscopic image was good and there was no image distortion, and a good image could be visually recognized. However, in this embodiment, the preferable range of the thickness T of the base material layer is set to 25 μm ≦ T ≦ 50 μm, and the reason why these lens sheets are used as comparative examples is that the arrangement of unit lenses and unit prisms is achieved by fine pitch. This is because when the pitch P is made smaller, a stereoscopic image becomes unclear with a lens sheet where T> 50 μm.

From the above, according to the present embodiment, the arrangement pitch P of the unit prisms 142 and the unit lenses 144 is 40 μm ≦ P ≦ 140 μm, and the thickness T of the base material layer 141 is 25 μm ≦ T ≦ 50 μm. Therefore, a fine pitch of the lens sheet can be realized, a stereoscopic image can be observed satisfactorily, and a good lens sheet in which image distortion due to the deflection of the lens sheet is not observed can be provided.
Further, according to the present embodiment, it is easy to align the unit lens 144 and the unit prism 142, and the accuracy can be very high.
Furthermore, according to the present embodiment, a molding die for molding the unit prism 142 is unnecessary, so that the production cost of the lens sheet can be suppressed, and a lens sheet with good optical performance can be provided at low cost.

(Deformation)
The present invention is not limited to the embodiment described above, and various modifications and changes are possible, and these are also within the scope of the present invention.
(1) In this embodiment, the example in which the base material layer 141 is continuously supplied from the lens layer forming process to the post-exposure process and various processes are performed on one line is shown, but the present invention is not limited thereto. For example, it may be wound and stored once after the lens layer forming step. Moreover, it is good also as a form from which a line is divided for every process. Further, a single substrate layer 141 may be used.

(2) In the present embodiment, the light guide plate 13 has an example in which dots (not shown) are formed on its back side surface by printing or the like. In addition, various unit lenses or the like may be arranged on the surface on the emission side (LCD panel 11 side), or a configuration in which dots or the like are not provided on the back surface may be adopted. For example, a plurality of prism shapes (for example, an arrangement pitch of about 90 μm and a height of about 2 μm) are formed on the back surface 13 d of the light guide plate 13, and a part of a substantially elliptic cylinder shape is formed on the output surface 13 c. A plurality of unit lenses (for example, an arrangement pitch of about 50 μm and a height of about 15 μm) having a shape or a partial shape of a substantially cylindrical shape may be formed.
In addition, the light guide plate 13 may include a diffusing material or the like.
Further, a reflection plate (not shown) or the like may be provided on the back side of the light guide plate 13. The reflecting plate is a member that can reflect light and reflects the light reflected toward the light guide plate 13 by the lens sheet 14 or the like and directs the light toward the lens sheet 14 again. By providing such a reflector, the light from the light source unit can be used more efficiently.

(3) In the present embodiment, the unit lens 144 of the lens sheet 14 is formed of an ultraviolet curable resin on the incident side of the base material layer 141. However, the present invention is not limited to this. For example, the lens layer 145 ( The unit lens 144) and the base material layer 141 may be made of a thermoplastic resin and integrally molded by hot melt extrusion molding or the like. By adopting such a form, the base material layer 141 and the unit lens 144 are formed at a time, so that the manufacture is easy.

(4) In this embodiment, the concave shape formed by the side surfaces of the unit prisms 142 adjacent to each other is such that the curve formed in the cross section that is parallel to the arrangement direction of the unit prisms 142 and orthogonal to the sheet surface approximates a parabola. However, the present invention is not limited to this. For example, the curve in the cross section may be approximated to a partial shape such as an arc shape or an elliptical shape, or approximated to a catenary curve (suspension curve). It is good also as a shape.

(5) In the present embodiment, as shown in FIG. 2, the unit prism 142 has an example in which the tip including the apex 142t has a pointed shape. However, the present invention is not limited to this example. It is good also as a form formed by the curved surface which becomes convex at the optical plate 13 side. By adopting such a configuration, the tip of the unit prism 142 is not easily damaged.

(6) In the present embodiment, the unit lens 144 is an example of a cylindrical lens having a substantially cylindrical partial shape. However, the unit lens 144 is not limited to this example. For example, the unit lens 144 has an elliptic cylinder shape whose long axis is orthogonal to the sheet surface. It is good also as a partial shape.

(7) In the present embodiment, the base layer 141 is made of PET resin. However, the present invention is not limited to this. For example, PC resin, TAC (triacetyl cellulose), PEN (polyethylene naphthalate) resin A sheet-like member can be used.

(8) In the present embodiment, the display device 10 has shown an example in which the screen size of the LCD panel 11 is 2.8 inches diagonal. However, the display device 10 is not limited to this, and may be a larger screen size, for example. The screen size may be set.
Further, in the present embodiment, the example in which the arrangement pitch of the sub-pixels in the horizontal direction of the screen of the LCD panel 11 is about 59 μm is shown, but the present invention is not limited to this and may be appropriately selected and used.

(9) In the present embodiment, the light source units 12A and 12B are LEDs as a light emission source and used in combination with a light guide. However, the present invention is not limited to this. For example, a cold cathode tube may be used as the light emission source. Good. At this time, a shutter capable of shielding light from the cold cathode tube may be provided between the cold cathode tube and the light guide plate, and the opening / closing of the shutter and the display of the image on the LCD panel 11 may be synchronized.

  In addition, although this embodiment and modification can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited by the above-described embodiments and the like.

DESCRIPTION OF SYMBOLS 10 Display apparatus 11 LCD panel 12A, 12B Light source part 13 Light guide plate 14 Lens sheet 141 Base material layer 142 Unit prism 143 Prism layer 144 Unit lens 145 Lens layer 15 Control part

Claims (10)

A base material layer;
A lens layer that is provided on the one surface and has a plurality of substantially cylindrical unit lenses that are convex on the exit side; and
A prism layer in which a plurality of unit prisms are arranged on the other surface of the base material layer, each having a substantially triangular prism shape that is convex on the incident side, and a curved surface having a concave side surface;
With
The arrangement direction of the unit lenses and the arrangement direction of the unit prisms are parallel, and the arrangement pitch of the unit lenses and the unit prisms is the same,
When viewed from the normal direction of the sheet surface, the vertex of the unit prism is a method of manufacturing a lens sheet that coincides with the vertex of the unit lens,
A lens layer forming step of forming a lens layer in which a plurality of the unit lenses are arranged on one surface of the base material layer;
A coating film forming step of forming a coating film of ionizing radiation curable resin on the surface opposite to the surface on which the lens layer is formed;
Irradiating ionizing radiation, which is substantially parallel light, along the direction substantially perpendicular to the sheet surface of the base material layer from the lens layer side, and the coating of the portion through which the ionizing radiation collected by the unit lens is transmitted. An exposure step of exposing and curing the film;
The removal process of removing the uncured part by the development process without being exposed in the exposure process in the coating film,
With
In the lens layer forming step,
The base material layer has a thickness T satisfying 25 μm ≦ T ≦ 50 μm,
The unit lenses are formed such that an arrangement pitch P satisfies 40 μm ≦ P ≦ 140 μm;
A manufacturing method of a lens sheet characterized by the above. In the manufacturing method of the lens sheet according to claim 1,
A post-exposure step of irradiating ionizing radiation from the prism layer side after the removing step;
A manufacturing method of a lens sheet characterized by the above. In the manufacturing method of the lens sheet according to claim 1 or 2,
In the cross section perpendicular to the sheet surface, the curve formed by one of the side surfaces of the unit prism and the side surface of the unit prism adjacent to the side surface is parallel to the arrangement direction of the unit prisms. To be substantially parabolic or catenary curved,
A manufacturing method of a lens sheet characterized by the above. In the manufacturing method of the lens sheet according to any one of claims 1 to 3,
The lens layer forming step includes
Ionizing radiation curable resin is applied to a mold for shaping the unit lens,
Pressing the base material layer against the mold,
Irradiating ionizing radiation to cure the ionizing radiation curable resin to transfer the shape of the unit lens,
Peeling the base material layer integrated with the ionizing radiation curable resin onto which the shape of the unit lens has been transferred, from the mold;
A manufacturing method of a lens sheet characterized by the above.   The lens sheet produced by the manufacturing method of the lens sheet of any one of Claim 1- Claim 4. Used for a surface light source device that irradiates a transmissive display unit of a transmissive display device capable of displaying a stereoscopic image by alternately emitting right-eye video light and left-eye video light in predetermined directions. A lens sheet,
A base material layer;
A lens layer provided on the exit side surface of the base material layer, and a plurality of substantially cylindrical unit lenses that are convex on the exit side; and
A prism layer in which a plurality of unit prisms are arranged on a surface on the incident side of the base material layer, the unit prisms having a substantially triangular prism shape convex to the incident side and having a curved side surface;
With
The arrangement direction of the unit lenses and the arrangement direction of the unit prisms are parallel, and the arrangement pitch of the unit lenses and the unit prisms is the same,
Seen from the normal direction of the sheet surface, the vertex of the unit prism coincides with the vertex of the unit lens,
The thickness T of the base material layer satisfies 25 μm ≦ T ≦ 50 μm,
The arrangement pitch P of the unit lenses and the unit prisms satisfies 40 μm ≦ P ≦ 140 μm,
Lens sheet characterized by In the lens sheet according to claim 5 or 6,
The vertex of the unit prism is closer to the unit lens side in the thickness direction of the lens sheet than the focal position of the substantially parallel light when irradiated with substantially parallel light from the unit lens side along the normal direction of the sheet surface. Located in the
Lens sheet characterized by In the lens sheet according to any one of claims 5 to 7,
The curve formed in a cross section in which the one side surface of the unit prism and the side surface of the adjacent unit prism are parallel to the arrangement direction of the unit prism and orthogonal to the sheet surface is a substantially parabolic or catenary curve. Be
Lens sheet characterized by The lens sheet according to any one of claims 5 to 8,
A light guide plate disposed on the incident side of the lens sheet;
A first light source unit and a second light source unit, which are arranged on two end faces of the light guide plate facing each other in the arrangement direction of the unit lens and the unit prism, and alternately repeat light emission and extinction;
A surface light source device comprising: A surface light source device according to claim 9,
A transmissive display unit that alternately displays a right-eye image and a left-eye image that are irradiated from the back side by the surface light source device and have parallax;
With
The transmissive display unit is
When the first light source unit emits light, the right eye image is displayed,
When the second light source unit emits light, the left eye image is displayed,
Making it possible to display a stereoscopic image by switching a display image in synchronization with light emission of the first light source unit and the second light source unit;
A transmissive display device characterized by the above.

Images