JP5995131B2 - Optical panel and display device - Google Patents

Description

  The present invention relates to an optical panel for changing the traveling direction of light from an original image incident from one side, transmitting to the other side, and displaying an image on the other side, and a display device including the optical panel. In particular, the present invention relates to an optical panel and a display device that can effectively prevent an unintended image from being observed.

  For example, as disclosed in Patent Document 1, a device that changes the traveling direction of light from an original image incident from one side and transmits the light to the other side and displays the image on the other side is known. . The optical imaging apparatus disclosed in Patent Document 1 has two light control panels each having a large number of strip-like reflecting portions arranged in parallel. In each control panel, a large number of light reflecting portions are arranged such that the reflecting surface is parallel to the normal direction of the panel. The two light control panels are overlapped so that the arrangement directions of the light reflecting portions are orthogonal to each other. According to the optical imaging device of Patent Document 1, the light beam from the three-dimensional model is reflected by the light reflecting portion of each light control panel, so that the three-dimensional model is located in a plane-symmetric position about the panel surface of the light control panel. Can be formed.

JP 2011-175297 A

  However, when the apparatus disclosed in Patent Document 1 is used, that is, when an apparatus having reflective surfaces arranged in a matrix is used, there may be a problem that an unintended image is displayed. In particular, when an unintended image is observed from a direction in which an image to be originally displayed can be observed, that is, when it is observed simultaneously with an image to be originally displayed, the visibility of the image to be originally displayed is visible. Will be significantly degraded.

  The present invention has been made in consideration of such points, and changes the traveling direction of light from the original image incident from one side to transmit to the other side and display the image on the other side. An object of the present invention is to provide an optical panel that effectively suppresses the observation of an unintended image. In addition, the present invention is a display device for changing the traveling direction of light from an original image incident from one side, transmitting to the other side, and displaying the image on the other side. It is an object to provide a display device that effectively suppresses observation.

The optical panel according to the present invention comprises:
In the optical panel for changing the traveling direction of light from the original image incident from one side and transmitting to the other side and displaying the image on the other side,
A plurality of first light transmitting portions arranged in a first arrangement direction, each having a plurality of first reflecting surfaces each of which is parallel to each other and reflects light from the original image incident from the one side. A first optical sheet including a light transmission part;
A second optical sheet disposed on the other side of the first optical sheet, and a plurality of second light transmission portions arranged in a second arrangement direction intersecting the first arrangement direction, A second optical sheet including a plurality of second light transmitting portions each having a second reflecting surface parallel to each other that reflects light from the original image transmitted through the one optical sheet,
The width of the first light transmission portion along the first arrangement direction is narrower than the end portion on the one side at the end portion on the other side, and the first light transmission portion along the second arrangement direction The width | variety of 2 light transmission part is narrower than the edge part of said one side in the edge part of said other side.

  In the optical panel according to the present invention, the width of the first light transmission portion along the first arrangement direction changes only so as to become narrower from the one side toward the other side, and the second arrangement direction. The width of the second light transmission portion along the line may change only so as to become narrower from the one side toward the other side.

  In the optical panel according to the present invention, the width of the first light transmission part along the first arrangement direction continues to change so as to become narrower from the one side toward the other side, and the second arrangement direction The width of the second light transmission part along the line may continue to change so as to become narrower from the one side toward the other side.

  In the optical panel according to the present invention, the first light transmission portion has a trapezoidal shape in a cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction. In addition, the second light transmission portion may have a trapezoidal shape in a cross section of the second optical sheet parallel to both the normal direction to the second optical sheet and the second arrangement direction.

  In the optical panel according to the present invention, a side corresponding to the trapezoidal first reflecting surface formed by the first light transmitting portion is orthogonal to the upper and lower bases of the trapezoidal shape, and the second light transmitting portion The side of the trapezoidal shape corresponding to the second reflecting surface may be orthogonal to the upper and lower bases of the trapezoidal shape.

  In the optical panel according to the present invention, the first optical sheet is formed between two adjacent first light transmission parts using a resin having a lower refractive index than the first light transmission part. The second optical sheet is further formed using a resin having a lower refractive index than the second light transmission part between the two adjacent second light transmission parts. The second low refractive index portion may be further provided.

In the optical panel according to the present invention, in the cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction, an end on the other side of the first light transmission portion The width along the first arrangement direction in the section is W1b, the height of the first light transmission section along the normal direction to the first optical sheet is H1, and the material forming the first light transmission section Where n1a is the refractive index of the resin and n1b is the refractive index of the resin constituting the first low refractive index portion, the following equation (1) is satisfied:
n1a × sin (arctan (H1 / W1b) ≧ n1b --- Equation (1)
In the cross section of the second optical sheet parallel to both the normal direction to the second optical sheet and the second arrangement direction, the second arrangement direction at the other side end of the second light transmission portion W2b, the height of the second light transmission part along the normal direction to the second optical sheet is H2, the refractive index of the material forming the second light transmission part is n2a, When the refractive index of the resin constituting the second low refractive index portion is n2b, the following formula (2) may be satisfied.
n2a x sin (arctan (H2 / W2b) ≥ n2b --- Equation (2)
In the optical panel according to the present invention, when the expressions (1) and (2) are satisfied, the following expressions (1a) and (2a) may be satisfied.
n1a x sin (arctan (H1 / W1a) <n1b --- Equation (1a)
n2a x sin (arctan (H2 / W2a) <n2b --- Equation (2a)
In addition, in the formula (1a) and the formula (2a), the first light transmitting portion in the cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction. W1a is the width along the first arrangement direction at the end of the one side of the first light transmission portion, and H1 is the height of the first light transmission portion along the normal direction to the first optical sheet. The refractive index of the material forming one light transmitting portion is n1a, the refractive index of the resin forming the first low refractive index portion is n1b, and the normal direction to the second optical sheet and the second arrangement direction In the cross section of the second optical sheet parallel to both, the width along the second arrangement direction at the end portion on the one side of the second light transmitting portion is defined as W2a, and the method for the second optical sheet is performed. The height of the second light transmission portion along the line direction is H2. , The refractive index of the material of the second light transmitting portion and n2a, have a n2b the refractive index of the resin forming the second low refractive index portion.

In the optical panel according to the present invention, in the cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction, an end on the one side of the first light transmission portion W1a is the width along the first arrangement direction in the section, and H1 is the height of the first light transmission section along the normal direction to the first optical sheet, and the material forming the first light transmission section Where n1a is the refractive index of the resin and n1b is the refractive index of the resin constituting the first low refractive index portion, the following equation (3) is satisfied:
n1a x sin (arctan (H1 / W1a) ≥ n1b --- Equation (3)
In the cross section of the second optical sheet parallel to both the normal direction to the second optical sheet and the second arrangement direction, the second arrangement direction at the end on the one side of the second light transmission portion W2a, the height of the second light transmission part along the normal direction to the second optical sheet is H2, the refractive index of the material forming the second light transmission part is n2a, When the refractive index of the resin constituting the second low refractive index portion is n2b, the following formula (4) may be satisfied.
n2a x sin (arctan (H2 / W2a) ≥ n2b --- Equation (4)

In the optical panel according to the present invention, in the cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction, an end on the one side of the first light transmission portion W1a is the width along the first arrangement direction in the section, and H1 is the height of the first light transmission section along the normal direction to the first optical sheet, and the material forming the first light transmission section Where n1a is the refractive index of the resin and n1b is the refractive index of the resin constituting the first low refractive index portion, the following equation (5) is satisfied:
n1a × sin (arctan (H1 / W1a) = n1b --- Equation (5)
In the cross section of the second optical sheet parallel to both the normal direction to the second optical sheet and the second arrangement direction, the second arrangement direction at the end on the one side of the second light transmission portion W2a, the height of the second light transmission part along the normal direction to the second optical sheet is H2, the refractive index of the material forming the second light transmission part is n2a, When the refractive index of the resin constituting the second low refractive index portion is n2b, the following formula (6) may be satisfied.
n2a x sin (arctan (H2 / W2a) = n2b --- Equation (6)

  In the optical panel according to the present invention, light-absorbing particles may be dispersed in the resin of the low refractive index portion.

  The display device according to the present invention includes any of the optical panels according to the present invention described above.

  According to the present invention, it is possible to effectively prevent an unintended image from being observed.

FIG. 1 is a perspective view showing a display device for explaining an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the display device of FIG. FIG. 3 is a partial perspective view showing an optical panel incorporated in the display device of FIG. FIG. 4 is a diagram showing the optical sheet incorporated in the optical panel of FIG. 3 in a cross section along both the normal direction and the arrangement direction of the light transmission portions. FIG. 5 is a cross-sectional view showing the optical sheet in the same cross section as FIG. 4, and is a view for explaining an optical path of light that is reflected once through the light transmitting portion of the optical sheet and forms an image. is there. FIG. 6 is a cross-sectional view showing the optical sheet in the same cross section as FIG. 4, and the light that does not reflect (passes through) the light transmitting portion of the optical sheet and transmits an unintended image (ghost). It is a figure for demonstrating these optical paths. FIG. 7 is a cross-sectional view showing the optical sheet in the same cross section as FIG. 4, and illustrates an optical path of light that is reflected twice through the light transmitting portion of the optical sheet and forms an unintended image (ghost). It is a figure for doing. FIG. 8 is a diagram for explaining what kind of image can be observed from each direction in the cross section similar to FIG. 4.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

  1-8 is a figure for demonstrating one Embodiment by this invention. Among these, FIG. 1 and FIG. 2 are the perspective view and longitudinal cross-sectional view which show a display apparatus. FIG. 3 is a partial perspective view showing the optical panel incorporated in the display device. 4-8 is sectional drawing which shows the optical sheet integrated in the optical panel.

  As shown in FIGS. 1 and 2, the display device 10 includes an optical panel 20 that changes the traveling direction of light from an original image (original image) 91 incident from one side and transmits the light to the other side, And a casing 15 that supports the optical panel 20. In the illustrated display device 10, a conical solid model is disposed in the casing 15 as an original image 91. Therefore, in the illustrated example, the inside of the casing 15 is one side of the optical panel 20, that is, the light incident side, and the outside of the casing is the other side of the optical panel 20. The optical panel 20 reflects the light from the original image 91 in two different directions da and db parallel to the panel surface, so that it is the same as the original image that is a real image on the other side of the optical panel 20, that is, the light output side. A virtual image 92 is formed.

  The casing 15 is formed in a box shape, and supports the optical panel 20 on the upper surface 15a. The upper surface 15a of the casing 15 is inclined with respect to the bottom surface 15b by 45 °, for example. The object (cone) that becomes the original image 91 is disposed in the casing 15 at a position that does not face the normal direction nd to the panel surface of the optical panel 20. The virtual image 92 formed by the optical panel 20 is observed at a position not facing the normal direction nd to the panel surface of the optical panel 20. In particular, in the illustrated example, according to the configuration of the optical panel 20 described below, the virtual image 92 has a panel plane of the optical panel 20 as a center plane and is in a plane symmetric with respect to the original image 91. Will be observed.

  In the present specification, terms such as “sheet”, “film”, and “plate” are not distinguished from each other only based on the difference in names. Therefore, for example, a “sheet” is a concept including a member that can also be called a film or a plate. As a specific example, the “optical sheet” includes members called “optical film”, “optical plate”, and the like.

  Further, in this specification, the “sheet surface (film surface, plate surface, panel surface)” is the plane of the target sheet-like member when the target sheet-like member is viewed as a whole and globally. A surface that matches the direction.

  Furthermore, terms used in the present specification for specifying shapes and geometric conditions, for example, terms such as “parallel”, “orthogonal”, “symmetric”, “trapezoid” and the like are not restricted to strict meanings. Therefore, it should be interpreted including an error to the extent that a similar optical function can be expected.

  Hereinafter, the configuration and operational effects of the optical panel 20 will be described in more detail. As shown in FIG. 3, the optical panel 20 includes a first optical sheet 30 and a second optical sheet 40 disposed on the other side of the first optical sheet 30, that is, the light output side. The first optical sheet 30 includes a sheet-like first base portion 31 and a first light transmission portion 35 arranged on the first base portion 31, and the second optical sheet 40 includes a sheet-like first base portion 31. It has two base parts 41 and a second light transmission part 45 arranged on the second base part 41. In the following, the optical sheets 30 and 40 will be described in more detail. In the following description, when the terms “first” and “second” are used and the symbols in the 30s and 40s are listed and described, For example, when using the terms “optical sheet 30, 40”, “base 31, 41”, and “light transmission part 35, 45”, both the first optical sheet 30 and the second optical sheet 40 are used. This is a true explanation. In particular, in the illustrated embodiment, the first optical sheet 30 and the second optical sheet 40 are configured identically. 4 to 8 are diagrams showing both the first optical sheet 30 and the second optical sheet 40 that are configured identically.

  The bases 31 and 41 are layers that support the light transmission parts 35 and 45, and are appropriately configured so as to have appropriate strength and appropriate transparency. As an example, the thickness of the base portions 31 and 41 can be 20 μm to 200 μm. As such base portions 31 and 41, for example, a biaxially stretched polyethylene terephthalate (PET) film can be used. The biaxially stretched polyethylene terephthalate film is suitable for application as the base portions 31 and 41 in that it has appropriate transparency and durability against ultraviolet irradiation treatment, heat treatment, and the like.

  As shown in FIG. 3, the light transmitting portions 35 and 45 are arranged on the other side surface (light emitting side surface) of the base portions 31 and 41 along the arrangement directions da and db parallel to the surface. . The light transmitting portions 35 and 45 extend linearly in a direction that intersects with the arrangement directions da and db and is parallel to the surface on the other side of the base portions 31 and 41. In particular, in the illustrated example, the light transmitting portions 35 and 45 extend linearly in a direction orthogonal to the arrangement directions da and db. The light transmission parts 35 and 45 may be arranged on the bases 31 and 41 without a gap, or may be arranged on the bases 31 and 41 with a gap as shown in FIG.

  Each first light transmitting portion 35 of the first optical sheet 30 has a first reflecting surface 36 that reflects light from the original image 91 incident from one side, and each second light sheet 40 of the second optical sheet 40 has a second reflecting surface 36. The light transmission part 45 has a second reflection surface 46 that reflects light from the original image 91 incident from one side. The first reflective surfaces 36 are parallel to each other between the multiple first light transmitting portions 35 included in the first optical sheet 30. In addition, the second reflecting surfaces 46 are parallel to each other between the multiple second light transmitting portions 45 included in the second optical sheet 40.

  As shown in FIG. 3, the first optical sheet 30 and the second optical sheet are arranged so that the arrangement direction da of the first light transmission part 35 and the arrangement direction db of the second light transmission part 45 intersect each other. Are arranged so as to overlap each other. In particular, in the present embodiment, the first optical sheet 30 and the second optical sheet are positioned relative to each other such that the arrangement direction da of the first light transmission portions 35 and the arrangement direction db of the second light transmission portions 45 are orthogonal to each other. Is positioned.

  In the embodiment described here, the first optical sheet 30 has a first low refractive index portion 38 disposed between two adjacent first light transmission portions 35, and the second optical sheet 40 is adjacent. A second low refractive index portion 48 is disposed between the two second light transmission portions 45. As shown in FIGS. 3 and 4, the low refractive index portions 38 and 48 are adjacent to the light transmitting portions 38 and 48 on the base portions 31 and 41, and the light transmitting portions 38 and 48 in the arrangement directions da and db. They are arranged alternately. Further, the low refractive index portions 38 and 48 extend linearly in a direction intersecting with the arrangement directions da and db and parallel to the surface on the other side of the base portions 31 and 41. That is, the low refractive index portions 38 and 48 are arranged on the base portion 40 in a stripe arrangement like the light transmitting portions 35 and 45.

  The first low refractive index portion 38 is formed using a resin having a lower refractive index than that of the first light transmitting portion 35, and is reflected at the interface between the first low refractive index portion 38 and the first light transmitting portion 35. It is intended to cause total reflection due to the refractive index difference. Similarly, the second low refractive index portion 48 is formed using a resin having a lower refractive index than the second light transmission portion 45, and is formed at the interface between the second low refractive index portion 48 and the second light transmission portion 45. It is intended to cause reflection, especially total reflection due to refractive index differences.

  As shown in FIG. 4, in the present embodiment, the first low refractive index portion 38 of the first optical sheet 30 and the second low refractive index portion 48 of the second optical sheet 40 are both light transmitting portions 35 and 45. And main portions 39a and 49a made of a resin having a lower refractive index, and light absorbing particles 39b and 49b dispersed in the main portions 39a and 49a. The light absorbing particles 39b and 49b are granular materials having a function of absorbing visible light. Accordingly, in the optical sheets 30 and 40, at the interfaces between the light transmitting portions 35 and 45 and the low refractive index portions 38 and 48. The light that has entered the low refractive index portions 38 and 48 without being reflected can be absorbed by the light absorbing particles 39b and 49b. In the optical sheets 30 and 40 described here, the visible light absorption function of the light absorbing particles 39b and 49b can improve the contrast of the displayed image.

  Next, the cross-sectional shapes of the light transmitting portions 35 and 45 and the low refractive index portions 38 and 48 will be described mainly with reference to FIGS. FIG. 4 is a cross-sectional view (also referred to as a main cutting surface of the optical sheet) along the arrangement direction da, db of the light transmitting portions 35, 45 of the optical sheets 30, 40 and the normal direction nd of the optical sheets 30, 40. It is a figure which shows the sheets 30 and 40. FIG.

  As shown in FIGS. 4-7, in the main cut surface of the first optical sheet, the width W1 of the first light transmission part 35 along the first arrangement direction da is at the end of the other side (light emission side). The width W2 of the second light transmission part 45 along the second arrangement direction db on the main cut surface of the second optical sheet is narrower than the end on one side (light incident side). Is narrower than the end on one side. That is, the width W1b of the first light transmission part 35 at the light exit side end is narrower than the width W1a of the first light transmission part 35 at the light incident side end, and the second light transmission part at the light output side end. The width W2b of 45 is narrower than the width W2a of the second light transmission portion 45 at the light incident side end. According to such a configuration, as will be described later, a ghost attributed to light transmitted without reflecting the light transmitting portions 35 and 45 described later is not observed from a direction in which an unintended image does not appear clearly. The intended image 92 can be observed from the direction.

  In particular, in the example shown in FIGS. 4 to 7, the width W1 of the first light transmitting portion 35 along the first arrangement direction da is from one side (light incident side) to the other side (light emitting side). It only changes so that it becomes narrower, it does not change so that it becomes wider. Similarly, the width W2 of the second light transmission portion 45 along the second arrangement direction db changes only so as to become narrower from one side (light incident side) to the other side (light output side), and is wide. Will not change. 4 to 7, the width W1 of the first light transmission portion 35 along the first arrangement direction da is from one side (light incident side) to the other side (light output side). The width W2 of the second light transmission part 45 along the second arrangement direction db is narrowed from one side (light incident side) to the other side (light output side). It continues to change.

  Furthermore, in the example shown in FIGS. 4 to 7, the surface extending from one side of the first light transmission portion 35 to the other side is formed linearly on the main cut surface of the first optical sheet, The surface extending from one side of the second light transmission part 45 to the other side is formed linearly on the main cut surface of the second optical sheet. Furthermore, as shown in FIGS. 4-7, the 1st light transmission part 35 becomes trapezoid shape in the main cut surface of a 1st optical sheet, and the 2nd light transmission part 45 is a 2nd optical sheet. The main cut surface has a trapezoidal shape. And in this Embodiment, it is from the original image 91 by one of the two surfaces 36 and 37 extended from the one side of the 1st light transmission part 35 to the other side in the main cut surface of a 1st optical sheet. The first reflecting surface 36 is formed which reflects the light of the first light and forms the image 92 on the other side. Similarly, light from the original image 91 is reflected by one of the two surfaces 46 and 47 extending from one side of the second light transmission portion 45 to the other side of the main cut surface of the second optical sheet. Thus, a second reflecting surface 46 for forming the image 92 on the other side is formed.

  As shown in FIGS. 4 to 7, one side corresponding to the trapezoidal first reflecting surface 36 formed by the first light transmitting portion 35 is orthogonal to the upper and lower bases of the trapezoidal shape, One side corresponding to the trapezoidal second reflecting surface 46 formed by the second light transmission part 45 is orthogonal to the upper and lower bases of the trapezoidal shape. That is, the first reflecting surface 36 of the first light transmitting portion 35 extends in the normal direction of the first optical sheet 30, and the second reflecting surface 46 of the second light transmitting portion 45 is the second optical sheet 40. It extends in the normal direction. In addition, the trapezoid shape which makes the cross-sectional shape of the light transmission parts 35 and 45 is arrange | positioned so that the upper base may make the surface 30b and 40b of the other side of an optical sheet, and the lower base is arrange | positioned at one side.

In addition, the optical panel 20 according to the present embodiment is configured as follows in order to enable the intended image 92 to be observed while effectively suppressing the unintended image from being observed. Yes. First, on the main cut surface of the first optical sheet, the width W1b at the other end (light emission side end) of the first light transmitting portion 35 along the first arrangement direction da, The height H1 of the first light transmitting portion 35 along the normal direction nd, the refractive index n1a of the material forming the first light transmitting portion 35, and the refraction of the resin forming the main portion 39a of the first low refractive index portion 38. The rate n1b satisfies the following formula (a). Similarly, on the main cut surface of the second optical sheet, the width W2b at the other end (light-emitting side end) of the second light transmission part 45 along the second arrangement direction db and the second optical sheet. The height H2 of the second light transmission portion 45 along the normal direction nd, the refractive index n2a of the material forming the second light transmission portion 45, and the resin forming the main portion 49a of the second low refractive index portion 48. The refractive index n2b satisfies the following formula (b). When the expression (a) or the expression (b) is satisfied, the ghost and the light transmission part caused by the transmitted light that is not reflected by the light transmission parts 35 and 45 to be described later in a state where an unintended image does not substantially appear. The intended image 92 can be observed brightly from the direction in which neither of the ghosts caused by the transmitted light reflected twice by 35 and 45 is observed.
n1a × sin (arctan (H1 / W1b) ≧ n1b --- Equation (a)
n2a x sin (arctan (H2 / W2b) ≥ n2b --- Equation (b)

Furthermore, on the main cut surface of the first optical sheet, a width W1a at one end (light-emitting side end) of the first light transmitting portion 35 along the first arrangement direction da, and the first optical sheet to the first optical sheet. The height H1 of the first light transmitting portion 35 along the normal direction nd, the refractive index n1a of the material forming the first light transmitting portion 35, and the refraction of the resin forming the main portion 39a of the first low refractive index portion 38. The rate n1b satisfies the following formula (c). Similarly, on the main cut surface of the second optical sheet, the width W2a at one end (light emission side end) of the second light transmission portion 45 along the second arrangement direction db and the second optical sheet. The height H2 of the second light transmission portion 45 along the normal direction nd, the refractive index n2a of the material forming the second light transmission portion 45, and the resin forming the main portion 49a of the second low refractive index portion 48. The refractive index n2b satisfies the following formula (d). When the expression (c) or the expression (d) is satisfied, a ghost and a light transmission part caused by transmitted light that is not reflected by the light transmission parts 35 and 45 described later in a state where an unintended image does not substantially appear. The intended image 92 can be observed brightly from the direction in which neither of the ghosts caused by the transmitted light reflected twice by 35 and 45 is observed.
n1a × sin (arctan (H1 / W1a) ≧ n1b --- Equation (c)
n2a x sin (arctan (H2 / W2a) ≥ n2b --- Equation (d)

  By the way, in the illustrated example, the two adjacent light transmission parts 35 and 45 are arranged with a gap along the arrangement directions da and db. For this reason, the low refractive index portions 38 and 48 provided in the two adjacent light transmission portions 35 and 45 have a quadrangular shape, particularly a trapezoidal shape, on the main cut surface of the optical sheet. The trapezoidal shape forming the cross-sectional shape of the low refractive index portions 38 and 48 is arranged such that the upper base is disposed on one side and the lower base forms the surfaces 30b and 40b on the other side of the optical sheets 30 and 40. Yes. That is, the other side of the optical sheets 30 and 40 is formed by the upper base of the trapezoidal shape that forms the cross-sectional shape of the light transmitting portions 35 and 45 and the lower base of the trapezoidal shape that forms the cross-sectional shape of the low refractive index portions 38 and 48. Surfaces (light-emitting side surfaces) 30b and 40b are formed. On the other hand, surfaces (light incident side surfaces) 30 a and 40 a on one side of the optical sheets 30 and 40 are formed by the base portions 31 and 41. As a result, each of the optical sheets 30 and 40 is configured as a sheet-like optical member having two parallel principal surfaces that are very easy to handle.

  However, the present invention is not limited to this example, and two adjacent light transmission portions 35 and 45 may be disposed adjacent to each other along the arrangement directions da and db. According to this example, the low refractive index portions 38 and 48 provided in the two adjacent light transmission portions 35 and 45 have a triangular shape, particularly a right triangle shape, on the main cutting surface of the optical sheet. Even in such an example. The optical sheets 30 and 40 may be configured as a sheet-like optical member having two parallel principal surfaces.

In addition, when the present inventors conducted intensive experiments, one end of the first light transmitting portion 35 (light emitting side end) along the first arrangement direction da on the main cut surface of the first optical sheet. , The width W1b at the other end (light-emitting side end) of the first light transmitting portion 35 along the first arrangement direction da, and the normal direction nd to the first optical sheet It has been found that the height H1 of the first light transmission part 35 preferably satisfies the following relationship when it is evaluated by a numerical value up to the first decimal place by rounding off.
2.0 ≦ H1 / W1a ≦ 5.0
1.5 ≦ W1a / W1b ≦ 3.5
Similarly, on the main cut surface of the second optical sheet, a width W2a at one end (light emission side end) of the second light transmission portion 45 along the second arrangement direction db and the second arrangement direction db Width W2b at the other side end portion (light output side end portion) of the second light transmission portion 45 along the height H2 of the second light transmission portion 45 along the normal direction nd to the second optical sheet. However, it has been found that it is preferable to satisfy the following relationship when rounded to the first decimal place.
2.0 ≦ H2 / W2a ≦ 5.0
1.5 ≦ W2a / W2b ≦ 3.5
When the light transmission parts 35 and 45 are designed so as to satisfy the above relationship, an observation angle region As where a ghost is not substantially observed, which will be described later, can be secured to a sufficient size, and the image 92 is also displayed. The optical sheet 30 and 40 including the light transmitting portions 35 and 45 can be manufactured at a low cost by molding.

  The optical sheets 30 and 40 having the above-described configuration can be manufactured as follows as an example.

  First, the light transmissive portions 35 and 45 have a characteristic of being cured by ionizing radiation such as an electron beam and ultraviolet rays, for example, a light transmissive portion constituting composition that becomes to constitute the light transmissive portions 35 and 45 by being cured. It can be made using an epoxy acrylate prepolymer or the like. Specifically, it corresponds to the mold roll having convex portions corresponding to the configuration (arrangement, shape, etc.) of the low refractive index portions 38, 48, in other words, corresponding to the configuration (arrangement, shape, etc.) of the light transmission portions 35, 45. A mold roll having a concave portion is prepared. The base sheet that forms the bases 31 and 41 is fed between the mold roll and the nip roll, and the light transmitting part constituting composition is placed between the mold roll and the base sheet in accordance with the feeding of the base sheet. To supply. Thereafter, the light transmitting portion constituting composition is pressed with a mold roll and a nip roll so that the liquid light transmitting portion constituting composition supplied in an uncured state on the base sheet is filled in the concave portion of the mold roll. At this time, the light transmitting portion constituting composition is supplied onto the base sheet so as to be thicker than the depth of the concave portion of the mold roll, that is, so that the mold roll and the base sheet do not come into contact with each other. The sheet-like portion formed integrally with the transmission portions 35 and 45 forms the base portions 31 and 41 together with the base material sheet. In this way, after filling the uncured and liquid light-transmitting portion constituting composition between the base sheet and the mold roll, the light-transmitting portion constituting composition is cured (solidified) by irradiation with ionizing radiation. Thus, the light transmitting portions 35 and 45 can be formed.

  Next, the low-refractive index portions 38 and 48 are light-absorbing containing urethane acrylate prepolymer having a characteristic of being cured by ionizing radiation that becomes the main portions 39a and 49a when cured, and carbon black, for example. It can be produced using an uncured and liquid low-refractive index constituent composition containing particles 39b and 49b. First, a low refractive index part constituent composition is supplied onto the light transmission parts 35 and 45 formed previously. Thereafter, the groove formed between the adjacent light transmitting portions 35 and 45, that is, the portion corresponding to the convex portion of the mold roll is filled with the low refractive index portion constituent composition while using a doctor blade. However, the excess low-refractive-index part constituent composition overflowing outside the groove is scraped off. Thereafter, the low refractive index portions 38 and 48 are formed by irradiating and curing the low refractive index portion constituting composition between the light transmitting portions 35 and 45 by ionizing radiation. Thereby, the optical sheets 30 and 40 which have the base parts 31 and 41 and the light transmission parts 35 and 45 and the low-refractive-index parts 38 and 48 which were arranged in stripes on the base part are produced.

  Next, functions and effects of the display device 10, the optical panel 20, and the optical sheets 30 and 40 configured as described above will be described.

  As shown in FIGS. 1 and 2, an original image that is a display target, that is, an original image 91 is arranged on one side (light incident side) of the optical panel 20 supported by the casing 15. In the example shown in FIGS. 1 and 2, the cone is disposed in the casing 15 as the original image 91. As shown in FIG. 3, light from the original image 91 enters the optical panel 20 from one side, changes the traveling direction, passes through the optical panel 20, and forms an image 92 on the other side. Become. Hereinafter, the image 92 formed on the other side of the optical panel 20 in this way is also referred to as a normal image 92 in order to distinguish it from an unintended image (ghost) described later. Further, in order to distinguish the light from the original image 91 that forms the normal image 92 on the other side of the optical panel 20 from the light that forms an unintended image (ghost) described later, the normal image from the original image 91 is used. Also called light.

  Light from the original image 91 enters the first optical sheet 30 disposed on one side of the optical panel 20. The first optical sheet 30 has a large number of first light transmission parts 35 arranged in the first arrangement direction da, and each first light transmission part 35 has a first reflection surface 36 parallel to each other. Each first reflective surface 36 is a surface parallel to the normal direction of the first optical sheet 30, in other words, the normal direction of the optical panel 20. Therefore, the first reflecting surface 36 of the first optical sheet 30 reflects regular light from the original image 91 so as to form an image that is specularly reflected by a surface parallel to the first reflecting surface 36.

  However, the second optical sheet 40 is disposed on the other side of the first optical sheet 30. The second optical sheet 40 has a large number of second light transmission parts 46 arranged in the second arrangement direction db, and each second light transmission part 46 has a second reflection surface 46 parallel to each other. Each second reflecting surface 46 is a surface parallel to the normal direction nd of the second optical sheet 40, in other words, the normal direction nd of the optical panel 30. For this reason, the second reflecting surface 46 of the second optical sheet 40 is the original after being reflected by the first reflecting surface 36 so as to form an image 92 that is specularly reflected by a surface parallel to the second reflecting surface 46. The regular light from the image 91 is reflected.

  As shown in FIG. 3, light traveling in various directions from each position of the original image 91 is transmitted from the first reflecting surface 36 in the first optical sheet 30 and the second reflecting surface 46 in the second optical sheet 40. The reflected light travels to a position symmetrical with respect to the position 91 of the original image with the panel surface of the optical panel 20 as the center. As a result, an image 92 that is plane-symmetric with the original image 91 about the panel surface of the optical panel 20 is formed at a position that is plane-symmetric with the original image 91 about the panel surface of the optical panel 20. When the observer 1 observes from the direction opposite to the traveling direction of the light traveling from the optical panel 20 toward the position symmetrical to the original image 91 about the panel surface of the optical panel 20, the other side of the optical panel 20 is observed. The elephant 92 formed on the side can be grasped three-dimensionally.

  As described above, the reflection surfaces 36 and 46 of the optical panel 20 extend in the normal direction nd of the optical panel 20. Therefore, when observing the normal image 92 formed on the other side, if the optical panel 20 and the original image 91 are arranged on the extended line in the observation direction, the real image 91 itself is displayed together with the normal image 92. More specifically, it is visually recognized from between the reflecting surfaces 36 and 46, and the visibility of the regular image 92 is significantly deteriorated. Therefore, as shown in FIGS. 1 and 2, the original image 91 is disposed at a position that does not face the optical panel 20 along the normal direction nd to the panel surface of the optical panel 20. Thereby, the observer observes the reproduced normal image 92 from a direction inclined to one side with respect to the normal direction nd to the panel surface of the optical panel 20. As a result, the normal image 92 and the real image 91 itself are prevented from being observed through the optical panel.

  However, when the inventors conducted experiments, as shown in FIGS. 1 and 2, the original image 91 is located at a position that does not face the optical panel 20 along the normal direction nd to the panel surface of the optical panel 20. Even if the normal image 92 is observed from a direction that is arranged and inclined with respect to the normal direction nd to the panel surface of the optical panel 20, an image different from the normal image 92, in particular, a shape similar to the normal image 92, is obtained. The ghost you have had been seen. According to the study by the present inventors, such an unintended image formation is caused by regular stray light traveling in the casing 15 reflected by the original image 91 and then transmitted through the optical panel 20 in the observation direction. On the other hand, according to the optical panel 20 of the present embodiment having the above-described configuration, it is possible to effectively suppress an unintended image from being observed. did it.

  As a result of extensive research, the present inventors have found that the ghost that can be visually recognized most clearly is an image caused by light that is transmitted through the light transmitting portions 35 and 45 without being reflected by the reflecting surfaces 36 and 46. The next ghost that can be visually recognized is an image caused by light reflected twice by the light transmission parts 35 and 45 and transmitted through the light transmission parts 35 and 45, while an image caused by other light ( For example, it has been found that an image caused by light reflected by the light transmitting portions 35 and 45 at least three times and transmitted through the light transmitting portions 35 and 45 cannot be visually recognized clearly. According to the optical panel 20 having the above-described configuration, the angle region Ab in which an image caused by the light transmitted through the light transmitting portions 35 and 45 without being reflected by the reflective surfaces 36 and 46 that are most easily sensed can be observed. An image caused by light transmitted through the light transmission parts 35 and 45 without being reflected by the reflection surfaces 36 and 46 and the light transmission parts 35 and 45 reflected twice by the light transmission parts 35 and 45 are reduced. It is possible to generate an angular region As in which both of the images caused by the transmitted light cannot be observed, and as a result, it is possible to effectively suppress the observation of an unintended image. Hereinafter, such an optical action will be described in detail with reference to the traveling direction of the light emitted from one optical sheet 30 or 40.

  First, the angle region Aa where the normal image 92 can be observed will be described mainly with reference to FIG. As a premise, as shown in FIG. 1 and FIG. 2, an original image 91 is arranged at a position not facing the optical panel 20 along the normal direction nd to the panel surface of the optical panel 20, and the panel of the optical panel 20 Assuming that the normal image 92 is observed from a direction inclined with respect to the normal direction nd to the surface, the same side as the original image 91 from the front direction nd of the optical panel 20 to the front direction nd of the optical panel 20 The normal image 92 can be observed from the direction inclined to the right.

  Next, the maximum angles θ1a and θ2a with respect to the normal direction nd of the optical sheets 30 and 40 in the observation direction in which the normal image 92 can be observed are directions in which the optical path of the light L5 in FIG. Is an angle formed with respect to the normal direction nd of the optical sheets 30 and 40. As shown in FIG. 5, the light L5 is an end on one side (light incident side) of the inclined surfaces 37 and 47 facing the reflecting surfaces 36 and 46 of the light transmitting portions 35 and 45 on the main cut surface of the optical sheet. After being incident on the light transmitting portions 35 and 45 through the optical path in contact with the portion and reflected by the reflecting surfaces 36 and 46, the light transmitting portions 35 and 45 come into contact with the other end (light emitting side) of the inclined surfaces 37 and 47. The light is emitted from the optical sheets 30 and 40 through the optical path.

The angle θ1a ′ that the traveling direction of the light L5 travels in the first light transmitting portion 35 of the first optical sheet 30 with respect to the normal direction nd of the first optical sheet 30 is expressed by the following equation (x1a). expressed. And when this light L5 radiate | emits from the 1st optical sheet 30, Snell's law represented by Formula (x1b) is satisfy | filled. Therefore, the angle θ1a formed by the emission direction of the light L5 from the first optical sheet 30 with respect to the normal direction nd of the first optical sheet 30 is expressed by the equation (x1c). Similar to the first optical sheet, the angle θ2a ′ formed by the traveling direction when the light L5 travels through the second light transmitting portion 45 of the second optical sheet 40 with respect to the normal direction nd of the second optical sheet 40 is: It is represented by the following formula (x2a). When the light L5 is emitted from the second optical sheet 30, Snell's law expressed by the equation (x2b) is satisfied, and the emission direction of the light L5 from the second optical sheet 40 is the second. An angle θ2a formed with respect to the normal direction nd of the optical sheet 40 is represented by an expression (x2c).
<First optical sheet>
θ1a '= arctan ((W1b + W1a) / H1) --- Expression (x1a)
n1a × sinθ1a '= sinθ1a --- Expression (x1b)
θ1a = arcsin (n1a × sin (arctan ((W1b + W1a) / H1))) --- Equation (x1c)
<Second optical sheet>
θ2a '= arctan ((W2b + W2a) / H2) --- Expression (x2a)
n2a × sinθ2a '= sinθ2a --- Expression (x2b)
θ2a = arcsin (n2a × sin (arctan ((W2b + W2a) / H2))) --- Equation (x2c)
Here, in the main cut surface of the first optical sheet, the width along the first arrangement direction da at the end on one side (light incident side) of the first light transmitting portion 35 is defined as W1a, and the first light transmitting portion The width along the first arrangement direction da at the end of the other side (light emission side) of W35 is W1b, and the height of the first light transmission portion 35 along the normal direction nd to the first optical sheet 30 is W1b. H1 and the refractive index of the material forming the first light transmission part 35 are n1a. Further, in the main cut surface of the second optical sheet, the width along the second arrangement direction db at the end portion on one side (light incident side) of the second light transmission portion 45 is W2a, and the second light transmission portion 45 is formed. W2b is the width along the second arrangement direction db at the end of the other side (light emission side), and the height of the second light transmission portion 45 along the normal direction nd to the second optical sheet 40 is H2. The refractive index of the material forming the second light transmission part 45 is n2a.

  Note that light traveling in a direction inclined more than the light L5 in FIG. 5 with respect to the normal direction nd of the optical sheets 30 and 40 is reflected by the reflecting surfaces 36 and 46 of the light transmitting portions 35 and 45, and then tilted. The surfaces 37 and 47 are also reflected. That is, it cannot be normal light forming the normal image 92. For this reason, the angular area Aa from which the normal light forming the normal image 92 is emitted from the first optical sheet 30 is greater than 0 ° with respect to the normal direction nd of the first optical sheet 30 and is expressed by the equation (x1c). The region is inclined at an angle that is equal to or smaller than the angle θ1a. Further, the angular area Aa from which the normal light forming the normal image 92 is emitted from the second optical sheet 40 is greater than 0 ° with respect to the normal direction nd of the second optical sheet 40 and is represented by the formula (x2c). The region is inclined at an angle of θ2a or less.

  Next, mainly referring to FIG. 6, an angular region Ab in which a ghost (unintentional image) due to the light L6 that is transmitted through the light transmitting portions 35 and 45 without being reflected by the reflecting surfaces 36 and 46 can be observed. After that, mainly referring to FIG. 7, a ghost (unintended image) caused by the light L7 reflected twice by the light transmitting portions 35 and 45 and passing through the light transmitting portions 35 and 45 is observed. The obtained angle range Ac will be described. Here, as a premise, in order to examine whether or not a ghost is observed while observing the normal image 92, as shown in FIG. 8, with respect to the normal direction nd to the panel surface of the optical panel 20, Consider an angle region inclined to the same side as the angle region Aa where the normal image 92 can be observed.

  The ghost attributed to the light L6 that passes through the light transmitting portions 35 and 45 without being reflected by the reflecting surfaces 36 and 46, that is, the light L6 that passes through the light transmitting portions, is normal direction nd of the optical sheets 30 and 40. Can be observed from Further, the maximum angle θ1b with respect to the normal direction of the optical sheets 30 and 40 in the observation direction in which a ghost attributed to the light L6 that is transmitted through the light transmission portions 35 and 45 without being reflected by the reflection surfaces 36 and 46 can be observed. θ2b is an angle formed by the direction of taking the optical path of the light L6 in FIG. 6 and exiting from the optical sheets 30 and 40 with respect to the normal direction nd of the optical sheets 30 and 40. As shown in FIG. 6, the light L6 is transmitted through an optical path in contact with the end of one side (light incident side) of the reflecting surfaces 36 and 46 of the light transmitting portions 35 and 45 on the main cut surface of the optical sheet. An optical path that is incident on the portions 35 and 45 and is not reflected by the reflecting surfaces 36 and 46 and the inclined surfaces 37 and 47 and is in contact with the other end (light emitting side) of the inclined surfaces 37 and 47 of the light transmitting portions 35 and 45 Then, the light is emitted from the optical sheets 30 and 40.

The angle θ1b ′ that the traveling direction of the light L6 travels in the first light transmitting portion 35 of the first optical sheet 30 with respect to the normal direction nd of the first optical sheet 30 is expressed by the following equation (y1a). expressed. And when this light L6 radiate | emits from the 1st optical sheet 30, Snell's law represented by Formula (y1b) is satisfy | filled. Therefore, the angle θ1b formed by the emission direction of the light L6 from the first optical sheet 30 with respect to the normal direction nd of the first optical sheet 30 is expressed by the equation (y1c). Similar to the first optical sheet, the angle θ2b ′ formed by the traveling direction when the light L6 travels in the second light transmitting portion 45 of the second optical sheet 40 with respect to the normal direction nd of the second optical sheet 40 is: It is represented by the following formula (y2a). When the light L6 is emitted from the second optical sheet 30, Snell's law expressed by the equation (y2b) is satisfied, and the emission direction of the light L6 from the second optical sheet 40 is the second. An angle θ2b formed with respect to the normal direction nd of the optical sheet 40 is represented by an expression (y2c).
<First optical sheet>
θ1b '= arctan (W1b / H1) --- expression (y1a)
n1a × sinθ1b '= sinθ1b --- expression (y1b)
θ1b = arcsin (n1a × sin (arctan (W1b / H1))) --- expression (y1c)
<Second optical sheet>
θ2b '= arctan (W2b / H2) --- expression (y2a)
n2a × sinθ2b '= sinθ2b --- expression (y2b)
θ2b = arcsin (n2a × sin (arctan (W2b / H2))) --- expression (y2c)
The symbols used in the formula (y1a), the formula (y1b), the formula (y1c), the formula (y2a), the formula (y2b), and the formula (y2c) are the same as the formulas (x1a), (x1b), and ( x1c), the expression (x2a), the expression (x2b), and the expression (x2c).

  Note that light traveling in a direction inclined more largely than the light L6 in FIG. 6 with respect to the normal direction nd of the optical sheets 30 and 40 is reflected at least by the inclined surfaces 37 and 47 of the light transmitting portions 35 and 45. . For this reason, the angle region Ab in which the light L6 that passes through the first light transmission part 35 without being reflected by the first reflection surface 36 that forms the ghost that is most clearly confirmed is emitted from the first optical sheet 30 is: The first optical sheet 30 is a region having an angle of 0 ° or more and an angle θ1b or less represented by the formula (y1c) with respect to the normal direction nd of the first optical sheet 30. In addition, the angle region Ab in which the light L6 that is transmitted through the second light transmitting portion 45 without being reflected by the second reflecting surface 46 that forms the most clearly confirmed ghost is emitted from the second optical sheet 40 is 2 An area having an angle of 0 ° or more and an angle θ2b or less represented by the formula (y2c) with respect to the normal direction nd of the optical sheet 40.

  On the other hand, as shown in FIG. 7, each of the optical sheets 30 and 40 in the observation direction in which a ghost attributed to the light L7 reflected twice by the light transmission portions 35 and 45 and transmitted through the light transmission portions 35 and 45 can be observed. The minimum angles θ1c and θ2c with respect to the normal direction are angles formed by the direction of taking the optical path of the light L7 in FIG. 7 and exiting from the optical sheets 30 and 40 with respect to the normal direction nd of the optical sheets 30 and 40. As shown in FIG. 7, the light L7 is reflected at the end of one side (light incident side) of the inclined surfaces 37, 47 of the light transmitting portions 35, 45 on the main cut surface of the optical sheet. Then, the light is incident on the light transmitting portions 35 and 45 and then is emitted from the optical sheets 30 and 40 while being reflected by the other end (light emitting side) of the reflecting surfaces 36 and 46 of the light transmitting portions 35 and 45.

The angle θ1c ′ that the traveling direction of the light L7 travels in the first light transmitting portion 35 of the first optical sheet 30 with respect to the normal direction nd of the first optical sheet 30 is expressed by the following equation (z1a). expressed. And when this light L7 radiate | emits from the 1st optical sheet 30, Snell's law represented by Formula (z1b) is satisfy | filled. Therefore, an angle θ1c formed by the emission direction of the light L7 from the first optical sheet 30 with respect to the normal direction nd of the first optical sheet 30 is expressed by an equation (z1c). Similar to the first optical sheet, the angle θ2c ′ formed by the traveling direction of the light L7 in the second light transmitting portion 45 of the second optical sheet 40 with respect to the normal direction nd of the second optical sheet 40 is It is represented by the following formula (z2a). When the light L7 is emitted from the second optical sheet 30, Snell's law expressed by the equation (z2b) is satisfied, and the emission direction of the light L7 from the second optical sheet 40 is the second. An angle θ2c formed with respect to the normal direction nd of the optical sheet 40 is represented by an expression (z2c).
<First optical sheet>
θ1c '= arctan (W1a / H1) --- expression (z1a)
n1a × sinθ1c '= sinθ1c --- Formula (z1b)
θ1c = arcsin (n1a × sin (arctan (W1a / H1))) --- Expression (z1c)
<Second optical sheet>
θ2c '= arctan (W2a / H2) --- Formula (z2a)
n2a × sinθ2c '= sinθ2c --- Formula (z2b)
θ2c = arcsin (n2a × sin (arctan (W2a / H2))) --- Expression (z2c)
The symbols used in the formula (z1a), the formula (z1b), the formula (z1c), the formula (z2a), the formula (z2b), and the formula (z2c) are the same as the formulas (x1a), (x1b), and ( x1c), the equation (x2a), the equation (x2b), and the symbol used in the equation (x2c).

  Even if the light traveling in the direction tilted smaller than the light L7 in FIG. 7 with respect to the normal direction nd of the optical sheets 30 and 40 is reflected by the inclined surfaces 37 and 47 of the light transmitting portions 35 and 45, In addition, the light is not reflected by the reflecting surfaces 36 and 46. For this reason, the angle region in which the light L7 reflected twice by the first light transmission part 35 that forms a ghost that is relatively clearly confirmed and transmitted through the first light transmission part 35 is emitted from the first optical sheet 30. Ac is a region that forms an angle equal to or greater than the angle θ1c represented by the formula (z1c) with respect to the normal direction nd of the first optical sheet 30. In addition, the angle region Ac where the light L7 reflected twice by the second light transmission part 45 that forms a ghost that is relatively clearly confirmed and transmitted through the second light transmission part 45 is emitted from the second optical sheet 40. Is a region that forms an angle equal to or larger than the angle θ2c represented by the formula (z2c) with respect to the normal direction nd of the second optical sheet 40.

  Here, based on the above examination results, when the optical sheets 30 and 40 are observed from a direction inclined to one side with respect to the normal direction nd of the optical sheets 30 and 40, the normal image 92 is observed. Angle region Aa that can be observed, the angle region Ab in which the most clearly confirmed ghost due to the light L6 that passes through the light transmission parts 35 and 45 without being reflected by the reflecting surfaces 36 and 46 can be observed, and light transmission FIG. 8 collectively shows an angular region Ac where a ghost that is relatively clearly confirmed due to the light L7 reflected twice by the portions 35 and 45 and transmitted through the light transmitting portions 35 and 45 can be observed.

  As described above, in the main cut surface of the first optical sheet, the width W1 of the first light transmission portion 35 along the first arrangement direction da is set to one side (input side) at the end of the other side (light output side). It is narrower than the edge on the light side. For this reason, the angle θ1b represented by the equation (y1c) is narrowed, and the most clearly confirmed ghost attributed to the light L6 transmitted through the first light transmitting portion 35 without being reflected by the first reflecting surface 36 is observed. The angular area Ab that can be made can be narrowed.

  In addition, since the width W1b of the first light transmission part 35 at the light output side end is narrower than the width W1a of the first light transmission part 35 at the light incident side end, the angle represented by the equation (y1c) θ1b is smaller than the angle θ1c represented by the formula (z1c). For this reason, the most clearly confirmed ghost attributed to the light L6 transmitted through the first light transmission part 35 without being reflected by the first reflection surface 36 and reflected twice by the first light transmission part 35 An angle region As is generated in which both of the ghosts that are relatively clearly confirmed due to the light L7 transmitted through the first light transmission part 35 cannot be visually recognized. Further, the angle θ1a represented by the expression (x1a) is larger than both the angle θ1b represented by the expression (y1c) and the angle θ1c represented by the expression (z1c). That is, in the main cut surface of the first optical sheet, the width W1 of the first light transmission portion 35 along the first arrangement direction da is one side (light incident side) at the other side (light emission side) end. If it is narrower than the end portion of the first optical sheet 30, it is caused by the light L 6 that is transmitted through the first light transmitting portion 35 without being reflected by the first reflecting surface 36 on the other side (light emission side) of the first optical sheet 30 Both the most clearly confirmed ghost and the relatively clearly confirmed ghost caused by the light L7 reflected twice by the first light transmitting portion 35 and transmitted through the first light transmitting portion 35 are visually recognized. It is possible to observe the intended normal image 92 in the angle range As that cannot be performed.

  Similarly to the first optical sheet 30, the width W2 of the second light transmission portion 45 along the second arrangement direction db is the end of the other side (light emission side) on the main cut surface of the second optical sheet. , The width W2b of the second light transmission portion 45 at the light output side end portion is smaller than the width W2a of the second light transmission portion 45 at the light input side end portion. Is also narrower. Therefore, it is possible to narrow the angular region Ab in which the most clearly confirmed ghost attributed to the light L6 transmitted through the second light transmitting portion 45 without being reflected by the second reflecting surface 46 can be observed. In addition, on the other side (light output side) of the second optical sheet 40, the ghost that is most clearly confirmed due to the light L6 that is transmitted through the second light transmitting portion 45 without being reflected by the second reflecting surface 46. In the angular region As where both of the ghosts that are reflected twice by the second light transmission part 45 and are relatively clearly confirmed due to the light L7 transmitted through the second light transmission part 45 cannot be visually recognized, It is possible to observe the intended normal image 92.

  From the above, on the other side of the optical panel 20, the most clearly confirmed ghost and light caused by the light L6 transmitted through the light transmitting portions 35 and 45 without being reflected by the reflecting surfaces 36 and 46, and the light The intended normal image in the angle region As where both of the ghosts that are reflected twice by the transmission parts 35 and 45 and are relatively clearly confirmed due to the light L7 transmitted through the light transmission parts 35 and 45 cannot be visually recognized. 92 can be observed. That is, it is possible to clearly observe the normal image 92 while suppressing the occurrence of ghosts that have deteriorated the visibility so far.

  By the way, in order for the normal image 92 to be observed brightly in the angle area As, it is effective to totally reflect at least a part of the normal light traveling toward the angle area As by the reflection surfaces 36 and 46. In this case, it is possible to secure a sufficient amount of normal light traveling in at least a part of the direction of the angle area As, and it is possible to observe the normal image 92 brightly while suppressing the occurrence of ghost. As an actual condition, light having the smallest emission angle (angle in the emission direction with respect to the normal direction of the optical sheet) out of the light emitted from the optical sheets 30 and 40 toward the angle region As, that is, FIG. The light L6a emitted in the direction parallel to the light L6 may be totally reflected by the reflecting surfaces 36 and 46 of the light transmitting portions 35 and 45.

When it is assumed that the light L6a travels along the main cutting surface of the optical sheet in order to make the conditions most strict, the incident angle of the light on the reflection surfaces 36 and 46 is (90−θ1b) in the first optical sheet. ') °, and (90-θ2b') ° in the second optical sheet. Here, “θ1b ′” and “θ2b ′” are values represented by the above-described equations (y1a) and (y2a), respectively. Therefore, when the already mentioned formula (a) is satisfied, the normal image 92 can be brightly observed on the other side of the first optical sheet 30 in the angle region As where the ghost does not substantially occur. . Similarly, when the formula (b) is satisfied, the normal image 92 can be observed brightly on the other side of the second optical sheet 40 in the angle region As where a ghost does not substantially occur.
n1a × sin (arctan (H1 / W1b) ≧ n1b --- Equation (a)
n2a x sin (arctan (H2 / W2b) ≥ n2b --- Equation (b)

  Further, it is more preferable that the normal image 92 is observed brightly in the angle area As, so that all of the normal light traveling toward the angle area As where substantially no ghost is generated is totally reflected by the reflection surfaces 36 and 46. It is. In this case, it is possible to secure a sufficient amount of normal light traveling in all directions within the angle region As, and it is possible to observe the normal image 92 brightly while suppressing the occurrence of ghosts. As an actual condition, light having the largest emission angle (angle in the emission direction with respect to the normal direction of the optical sheet) among the light emitted from the optical sheets 30 and 40 toward the angle region As, that is, FIG. Even the light L7a emitted in the direction parallel to the light L7 need only be totally reflected by the reflecting surfaces 36 and 46 of the light transmitting portions 35 and 45.

When it is assumed that the light L7a travels along the main cutting surface of the optical sheet in order to make the conditions most strict, the incident angle of the light on the reflection surfaces 36 and 46 is (90−θ1c) in the first optical sheet. ') °, and (90-θ2c') ° in the second optical sheet. Here, “θ1c ′” and “θ2c ′” are values represented by the above-described equations (z1a) and (z2a), respectively. Therefore, when the above-mentioned formula (c) is satisfied, the normal image 92 is brightly observed on all the directions in the angle region As where the ghost is not substantially generated on the other side of the first optical sheet 30. Is possible. Similarly, when the expression (d) is satisfied, the normal image 92 can be brightly observed in all directions within the angular region As where the ghost is not substantially generated on the other side of the second optical sheet 40. It becomes.
n1a × sin (arctan (H1 / W1a) ≧ n1b --- Equation (c)
n2a x sin (arctan (H2 / W2a) ≥ n2b --- Equation (d)

It is also preferable that the above-described expressions (a) and (b) are satisfied, and that the following expressions (e) and (f) are satisfied instead of the expressions (c) and (d).
n1a × sin (arctan (H1 / W1a) = n1b --- Equation (e)
n2a x sin (arctan (H2 / W2a) = n2b --- Equation (f)
When Expression (e) and Expression (f) are satisfied, the normal image 92 can be observed brightly in the entire area of the angle area As where ghost is not substantially generated, but in the angle area Ac, the normal image 92 is brightened. I can't observe. However, the angle area Ac is an area where a ghost attributed to the light L7 reflected twice by the light transmitting parts 35 and 45 and transmitted through the light transmitting parts 35 and 45 can be visually recognized. Therefore, when the expressions (e) and (f) are satisfied, the regular image 92 cannot be observed brightly in the angle region Ac, and is reflected twice by the light transmitting portions 35 and 45. The ghost attributed to the light L7 transmitted through the light transmitting portions 35 and 45 is no longer observed brightly.

Furthermore, the above-described expressions (a) and (b) may be satisfied, and the following expressions (g) and (h) may be satisfied instead of the expressions (c) and (d).
n1a x sin (arctan (H1 / W1a) <n1b --- expression (g)
n2a x sin (arctan (H2 / W2a) <n2b --- expression (h)
When the expressions (g) and (h) are satisfied, the normal image 92 cannot be observed brightly from a part of the angular region As where the ghost is not substantially generated. The ghost caused by the light L7 reflected twice at 45 and transmitted through the light transmitting portions 35, 45 is no longer observed brightly. That is, when the direction in which the normal image 92 is observed is determined to be a partial direction within the angular region As according to the application of the display device 10 and the like, together with the equations (a) and (b), the equation You may make it satisfy | fill (g) and Formula (h).

  By the way, in the optical sheets 30 and 40 described in the present embodiment, low refractive index portions 38 and 48 are provided between the light transmitting portions 35 and 45. The low refractive index portions 38 and 48 include light absorbing particles 39b and 39b having a function of absorbing visible light. For this reason, the light which absorbs the light from the outside which goes to the inside of the casing 15 from the outside of the casing 15 is absorbed by the light absorbing particles 39b and 39b, and the original image in the casing 15 is specified by the light from the outside. Illumination from the direction can be prevented. Thereby, generation | occurrence | production itself of the light from the original image 91 which comes to form a ghost can be suppressed effectively.

  As shown in FIG. 4, when the light transmitting portions 35 and 45 are provided with a gap, light L4a incident on the low refractive index portions 38 and 48 from the base portions 31 and 41 is also generated. Such light can form ghosts that are observed from a particular direction. When the low refractive index portions 38 and 48 have a light absorption function as in the present embodiment, such light L4a can also be absorbed and the occurrence of ghost can be suppressed.

  According to the present embodiment as described above, the width W1 of the first light transmission portion 35 along the first arrangement direction da is set to one side (light incident side) at the other side (light emission side) end. The width W2 of the second light transmission portion 45 along the second arrangement direction db is narrower than the end portion of the other side (light-emitting side), and the end on one side (light-incident side). It is narrower than the part. For this reason, the angle area Ab in which an unintended image caused by light transmitted through the light transmitting portions 35 and 45 without being reflected by the reflective surfaces 36 and 46 that are most easily sensed can be observed is narrowed, and the reflective surface 36 , 46 and unintentional images caused by the light transmitted through the light transmitting portions 35 and 45 and the light reflected twice by the light transmitting portions 35 and 45 and transmitted through the light transmitting portions 35 and 45 An angular region As where both unintended images cannot be observed can be generated, thereby effectively suppressing unintended images from being observed.

  Note that various modifications can be made to the above-described embodiment. Hereinafter, an example of modification will be described.

  For example, in the above-described embodiment, the original image 91 is an example of a real model. However, the present invention is not limited to this, and the original image itself may be an image formed as a video.

  In the above-described embodiment, an example in which only one optical panel 20 is provided in the display device 10 has been described. However, the present invention is not limited to this, and two or more optical panels 20 may be provided. In such a modification, the first optical panel forms a first image with light from the original image, and the second optical panel forms a second image with light forming the first image. You may make it do.

  Furthermore, in the above-described embodiment, the example in which the first optical sheet 30 and the second optical sheet 40 included in the optical panel 20 are configured in the same manner is shown, but the present invention is not limited thereto, and the first optical sheet 30 is not limited thereto. The second optical sheet 40 may be different from each other in configuration such as dimensions and shapes.

  Furthermore, in the above-described embodiment, an example in which the light-absorbing particles 39a and 49a having a function of absorbing visible light are mixed in the low refractive index portions 38 and 48 of the optical sheets 30 and 40 has been shown. It is not limited to this. Instead of the light absorbing particles 39a and 49a or in addition to the light absorbing particles 39a and 49a, particles having a function of reflecting visible light may be added to the low refractive index portions 38 and 48, or the low refractive index portion. 38 and 48 may not be mixed with particles.

  Furthermore, in the above-described embodiment, the example in which the optical sheets 30 and 40 have the low refractive index portions 38 and 48 has been described. However, the present invention is not limited thereto, and the low refractive index portions 38 and 48 may not be provided. . In such a modification, an air gap is formed between two adjacent light transmission portions 35 and 45, and the above-described formulas (a) to (h) are expressed by the refractive index n1b = 1 and the refractive index. In the case where n2b = 1 is satisfied, the same operational effects as in the case where the expressions (a) to (h) are satisfied in the above-described embodiment can be obtained.

  In addition, although the some modification with respect to embodiment mentioned above was demonstrated above, naturally, it is also possible to apply combining several modifications suitably.

DESCRIPTION OF SYMBOLS 10 Display apparatus 15 Casing 20 Optical panel 30 1st optical sheet 30a The surface of one side, the light-incidence side surface 30b The surface of the other side, the light emission side surface 31 Base 35 1st light transmission part 36 1st reflection surface 37 1st slope 38 First low refractive index portion 39a Main portion 39b Light absorbing particles 40 Second optical sheet 40a One side surface, light incident side surface 40b The other side surface, light exit side surface 41 Base 45 Second light transmission portion 46 Second reflection surface 47 Second slope 48 Second low refractive index portion 49a Main portion 49b Light absorbing particles

Claims (8)

Arranged along the normal direction at a position that does not face the original image, changes the traveling direction of light from the original image incident from one side, transmits to the other side, and forms an image on the other side In the optical panel for
A plurality of first light transmitting portions arranged in a first arrangement direction, each having a plurality of first reflecting surfaces each of which is parallel to each other and reflects light from the original image incident from the one side. A first optical sheet including a light transmission part;
A second optical sheet disposed on the other side of the first optical sheet, and a plurality of second light transmission portions arranged in a second arrangement direction intersecting the first arrangement direction, A second optical sheet including a plurality of second light transmitting portions each having a second reflecting surface parallel to each other that reflects light from the original image transmitted through the one optical sheet,
The width of the first light transmission portion along the first arrangement direction is narrower than the end portion on the one side at the end portion on the other side, and the first light transmission portion along the second arrangement direction The width of the 2 light transmission part is an optical panel which is narrower than the edge part of said one side in the edge part of said other side. The first optical sheet further includes a first low refractive index portion formed using a resin having a lower refractive index than the first light transmitting portion between two adjacent first light transmitting portions. Have
The second optical sheet further includes a second low refractive index portion formed between two adjacent second light transmitting portions using a resin having a lower refractive index than the second light transmitting portion. The optical panel according to claim 1. In the cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction, the first arrangement direction at the end on the other side of the first light transmission portion W1b, the height of the first light transmission part along the normal direction to the first optical sheet is H1, the refractive index of the material forming the first light transmission part is n1a, When the refractive index of the resin constituting the first low refractive index portion is n1b, the following equation (1) is satisfied:
n1a × sin (arctan (H1 / W1b) ≧ n1b --- Equation (1)
In the cross section of the second optical sheet parallel to both the normal direction to the second optical sheet and the second arrangement direction, the second arrangement direction at the other side end of the second light transmission portion W2b, the height of the second light transmission part along the normal direction to the second optical sheet is H2, the refractive index of the material forming the second light transmission part is n2a, The optical panel according to claim 2, wherein the following expression (2) is satisfied, where n2b is a refractive index of the resin constituting the second low refractive index portion.
n2a x sin (arctan (H2 / W2b) ≥ n2b --- Equation (2) In the cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction, the first arrangement direction at the end portion on the one side of the first light transmission portion W1a, the height of the first light transmission part along the normal direction to the first optical sheet is H1, the refractive index of the material forming the first light transmission part is n1a, When the refractive index of the resin constituting the first low refractive index portion is n1b, the following equation (3) is satisfied:
n1a x sin (arctan (H1 / W1a) ≥ n1b --- Equation (3)
In the cross section of the second optical sheet parallel to both the normal direction to the second optical sheet and the second arrangement direction, the second arrangement direction at the end on the one side of the second light transmission portion W2a, the height of the second light transmission part along the normal direction to the second optical sheet is H2, the refractive index of the material forming the second light transmission part is n2a, The optical panel according to claim 2 or 3, wherein the following expression (4) is satisfied, where n2b is a refractive index of the resin constituting the second low refractive index portion.
n2a x sin (arctan (H2 / W2a) ≥ n2b --- Equation (4) In the cross section of the first optical sheet parallel to both the normal direction to the first optical sheet and the first arrangement direction, the first arrangement direction at the end portion on the one side of the first light transmission portion W1a, the height of the first light transmission part along the normal direction to the first optical sheet is H1, the refractive index of the material forming the first light transmission part is n1a, When the refractive index of the resin constituting the first low refractive index portion is n1b, the following equation (5) is satisfied:
n1a × sin (arctan (H1 / W1a) = n1b --- Equation (5)
In the cross section of the second optical sheet parallel to both the normal direction to the second optical sheet and the second arrangement direction, the second arrangement direction at the end on the one side of the second light transmission portion W2a, the height of the second light transmission part along the normal direction to the second optical sheet is H2, the refractive index of the material forming the second light transmission part is n2a, The optical panel according to any one of claims 2 to 4, wherein the following formula (6) is satisfied, where n2b is a refractive index of the resin constituting the second low refractive index portion.
n2a x sin (arctan (H2 / W2a) = n2b --- Equation (6)   The optical panel according to claim 2, wherein light-absorbing particles are dispersed in the resin of the low refractive index portion.   The optical panel according to any one of claims 1 to 6, wherein the image is displayed in a plane-symmetrical direction at a plane-symmetrical position with respect to the original image with the panel surface of the optical panel as a center plane. Comprising the optical panel according to any one of claims 1 to 7,
A display device, wherein an arrangement region for arranging an original image is provided at a position that does not face the optical panel along a normal direction of the optical panel.

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