JP6375359B2 - Display panel unit and display device - Google Patents

Description

  Embodiments described herein relate generally to a display panel unit and a display device.

  2. Description of the Related Art Conventionally, there is a display device that includes a prism sheet that concentrates the spread angle of light from a light source in a predetermined range, and a reflective polarizer disposed to face the prism sheet. The reflective polarizer transmits, for example, a P-polarized component of light transmitted through a prism sheet to a display panel such as a liquid crystal panel and reflects an S-polarized component to a light source.

  The S-polarized component reflected by the reflective polarizer is reflected, for example, by an optical element such as a reflector provided on the light source side, and reaches the reflective polarizer again. By repeating such reflection, the S-polarized component is eventually converted into a P-polarized component and passes through the reflective polarizer. When a reflective polarizer is used, the use efficiency of light from the light source increases, so that the luminance of the display device can be increased.

JP 2003-177394 A JP 2006-147466 A JP 2010-231896 A

  In the display device configured as described above, light interference fringes may occur between the prism sheet and the reflective polarizer. Interference fringes are a cause of lowering the display quality of the display device.

  The problem to be solved by the present invention is to provide a display panel unit and a display device including a reflective polarizer capable of reducing or preventing the generation of the interference fringes.

  A display panel unit according to an embodiment is a display panel unit that faces a prism sheet disposed on a light source side, and includes a display panel, a reflective polarizing layer, and a transparent layer. The display panel controls light transmission.

The reflective polarizing layer has an incident surface on the light source side and an output surface on the display panel side, transmits a first polarization component of light incident from the incident surface to the output surface, and from the incident surface. A second polarization component orthogonal to the first polarization component of incident light is reflected to the light source side. The transparent layer is provided in close contact with the incident surface, transmits the first polarized component and the second polarized component of light from the light source side to the incident surface side, and reflects on the reflective polarizing layer. The second polarized component is transmitted to the light source side. In this display panel unit, the thickness of the transparent layer is 30 μm or more and 59 μm or less .

A display device according to an embodiment includes a backlight unit, a display panel, a reflective polarizing layer, a transparent layer, and a prism sheet. The backlight unit includes a light source and a light guide that takes in the light from the light source and emits the light from the emission surface. The display panel controls light transmission. The reflective polarizing layer has an incident surface on the backlight unit side and an output surface on the display panel side, and transmits the first polarization component of light incident from the incident surface to the output surface and the incident surface. A second polarization component orthogonal to the first polarization component of light incident from the surface is reflected to the backlight unit side. The transparent layer is provided in close contact with the incident surface, transmits the first polarized component and the second polarized component of light from the backlight unit side to the incident surface side, and is provided on the reflective polarized layer. Then, the second polarized component reflected is transmitted to the backlight unit side. The prism sheet has a prism surface on which a prism lens is formed, and is disposed between the transparent layer and the light guide so that the prism surface faces the transparent layer. In this display device, the transparent layer has a thickness of 30 μm or more and 59 μm or less.

1 is a cross-sectional view illustrating a schematic configuration of a liquid crystal display device according to an embodiment. Sectional drawing for demonstrating the structure of the reflective polarizing plate which concerns on one Embodiment. The schematic diagram for demonstrating the usage example of a liquid crystal display device. The figure which shows the structure and evaluation result of the liquid crystal display device which concern on an Example. The figure which shows the level of the interference fringe which generate | occur | produces in the liquid crystal display device which concerns on an Example. The figure which shows the comparative example of some methods for avoiding an interference fringe. Sectional drawing which shows schematic structure of a general liquid crystal display device. The schematic diagram of the interference fringe which appears on the display surface of a liquid crystal display device.

An embodiment will be described with reference to the drawings.
In this embodiment, a transmissive liquid crystal display device is disclosed as an example of a display device.

  First, a configuration example of a general liquid crystal display device and interference fringes generated in the display device will be described.

  FIG. 7 is a cross-sectional view showing a schematic configuration of a general liquid crystal display device 100. The liquid crystal display device 100 includes a backlight unit 110 and a display panel unit 130. A broken-line arrow in the figure indicates a part of a light path from the backlight unit 110.

  The backlight unit 110 includes, for example, a light source 111 that is a linear light source, a light guide 112 that takes in light from the light source 111 and emits uniform light toward the optical element group 120, and a light guide 112 in FIG. A reflection sheet 113 that reflects the light emitted downward to the light guide 112 and an optical element group 120.

  The optical element group 120 includes a diffusion sheet 121 that diffuses light from the light guide 112, and a first prism sheet 122 and a second prism that concentrate the spread angle of the light diffused by the diffusion sheet 121 in a predetermined angle range. A sheet 123. The surfaces of the first prism sheet 122 and the second prism sheet 123 on the display panel unit 130 side are prism surfaces on which a large number of prism lenses extending in a uniform cross-sectional shape are arranged in parallel. In addition, the cross-sectional shape of the prism lens is not limited to be uniform.

  The display panel unit 130 transmits the P-polarized component of the light from the optical element group 120 and reflects the S-polarized component orthogonal to the P-polarized component, and the light emitted from the reflective polarizer 131 A liquid crystal panel 132 that controls the transmission of light, and a polarizing plate 133 that transmits a predetermined polarization component included in the light transmitted through the liquid crystal panel 132. An air layer is provided between the second prism sheet 123 and the reflective polarizing plate 131.

  The S-polarized light component reflected by the reflective polarizing plate 131 is reflected by, for example, the prism surface of the second prism sheet 123 or the reflective sheet 113 and reaches the reflective polarizing plate 131 again. By repeating such reflection, the S-polarized component is eventually converted into a P-polarized component and is transmitted through the reflective polarizing plate 131.

  FIG. 7 shows a state in which the optical element group 120 is locally bent. Such bending occurs, for example, when the liquid crystal display device 100 receives an external force. Interference fringes appear on the display surface of the liquid crystal display device 100 due to the bending of the optical element group 120, particularly the bending of the second prism sheet 123.

  FIG. 8 schematically shows interference fringes appearing on the display surface. In the figure, d1 and d2 (d1 <d2) represent pitches in a part of the interference fringes. The interference fringes appear at a narrow pitch such as d1 at a location where the deflection of the second prism sheet 123 is large, and appear at a wide pitch such as d2 at a location where the deflection of the second prism sheet 123 is small.

  The interference fringes are light that is emitted from the light source 111 and reaches the second prism sheet 123, and light that is reflected by the reflective sheet 113 after being reflected by the reflective polarizing plate 131 and reaches the second prism sheet 123 again. Or the interference between the light and darkness formed along the prism lens of the second prism sheet 123 and the reflected image by the reflective polarizing plate 131. Any of these interferences occur due to the gap between the second prism sheet 123 and the reflective polarizing plate 131 becoming non-uniform and the gap becoming too small locally.

Next, the liquid crystal display device according to this embodiment will be described.
FIG. 1 is a cross-sectional view showing a schematic configuration of a liquid crystal display device 1 according to the present embodiment. The liquid crystal display device 1 includes a backlight unit 10 and a display panel unit 30. A broken-line arrow in the figure indicates a part of a light path from the backlight unit 10.

  The backlight unit 10 includes a light source 11, a light guide 12, a reflection sheet 13, and an optical element group 20. The light source 11 is configured, for example, by arranging a large number of point light sources in one end portion of the light guide 12 in a straight line. As the point light source, for example, an LED (Light Emitting Diode) or an organic EL (Organic ElectroLuminescence) can be used. The light source 11 may be a linear light source such as a cold cathode fluorescent tube or a hot cathode fluorescent tube. The light guide 12 takes in the light from the light source 11 and radiates uniform light toward the optical element group 20 from the upper emission surface in FIG. That is, the light guide 12 functions as a surface light source having a rectangular emission surface, for example. The reflection sheet 13 reflects the light emitted below the light guide 12 in FIG. 1 and returns it to the light guide 12.

  The optical element group 20 includes a diffusion sheet 21, a first prism sheet 22, and a second prism sheet 23 in order from the light guide 12 side. The diffusion sheet 21, the first prism sheet 22, and the second prism sheet 23 are formed to have substantially the same dimensions as the light exit surface of the light guide 12, and are laid on the light exit surface in order.

  The diffusion sheet 21 diffuses light from the light guide 12 and makes the luminance of light incident on the first prism sheet 22 substantially uniform. As the diffusion sheet 21, for example, a diffusion sheet having an uneven structure for diffusing light on the surface, or a diffusion sheet containing fine particles having a refractive index different from that of the main constituent material can be used. The first prism sheet 22 and the second prism sheet 23 have prism surfaces on which a large number of prism lenses extending in a uniform cross-sectional shape are arranged in parallel. The cross-sectional shape of the prism lens is, for example, a triangle whose apex angle is approximately 90 degrees. For example, the first prism sheet 22 and the second prism sheet 23 are arranged so that the ridgelines of the prism lens are orthogonal to each other. The cross-sectional shapes of the prism lenses of the first prism sheet 22 and the second prism sheet 23 are not limited to be uniform.

  The first prism sheet 22 and the second prism sheet 23 concentrate the light spreading angle diffused by the diffusion sheet 21 in a predetermined angle range by the action of the prism lens. The ends of the light source 11, the light guide 12, the reflection sheet 13, the diffusion sheet 21, the first prism sheet 22, and the second prism sheet 23 are held by a bezel (not shown), for example.

  The display panel unit 30 is disposed so as to face the emission side of the backlight unit 10 substantially in parallel, and is supported by a support frame or a bezel. The display panel unit 30 includes a reflective polarizing plate 31 as a reflective polarizer, a liquid crystal panel 32 as a display panel, and a polarizing plate 33 in order from the backlight unit 10 side.

  The liquid crystal panel 32 includes an array substrate 32a provided with a large number of pixel electrodes, a counter substrate 32b facing the array substrate 32a with a minute gap, and a liquid crystal sealed between the array substrate 32a and the counter substrate 32b. A liquid crystal layer made of the composition and a color filter for additively mixing RGB colors are included.

  A polarizing plate 33 is stuck on the emission surface of the liquid crystal panel 32, that is, the surface of the counter substrate 32 b, and faces the display area of the liquid crystal panel 32. A reflective polarizing plate 31 is attached to the incident surface of the liquid crystal panel 32, that is, the surface of the array substrate 32a, and faces the display area. The liquid crystal panel 32 selectively applies a voltage to each pixel electrode and controls transmission (transmission / non-transmission) of light emitted from the reflective polarizing plate 31. The light transmitted through the liquid crystal panel 32 has an unnecessary polarization component removed by the polarizing plate 33 and displays an image visible to the user.

  The reflective polarizing plate 31 includes a transparent layer 300 and a reflective polarizing layer 310 in order from the backlight unit 10 side. The transparent layer 300 is provided in close contact with the reflective polarizing layer 310. The reflective polarizing layer 310 transmits the first polarized component of the light from the backlight unit 10 side to the liquid crystal panel 32 side, and reflects the second polarized component of the light from the backlight unit 10 side to the backlight unit 10 side. Let The transparent layer 300 transmits the first polarization component and the second polarization component of the light from the backlight unit 10 side to the reflection polarization layer 310 side, and the second polarization component reflected by the reflection polarization layer 310 is backlit. Permeate to the unit 10 side. In the present embodiment, it is assumed that the first polarization component is a P polarization component and the second polarization component is an S polarization component orthogonal to the P polarization component. However, the reflective polarizing plate 31 or the liquid crystal display device 1 may be configured with the first polarization component as the S polarization component and the second polarization component as the P polarization component.

  A more detailed configuration of the reflective polarizing plate 31 will be described with reference to the cross-sectional view of FIG. The transparent layer 300 includes an HC (hard coat) layer 301, a transparent substrate 302, and a transparent adhesive layer 303 in this order from the backlight unit 10 side. The reflective polarizing layer 310 includes a reflective layer 311, a transparent adhesive layer 312, and a polarizing layer 313 in order from the backlight unit 10 side. In the following description, the surface on the transparent layer 300 side of the reflective layer 311 is referred to as an incident surface 310a, and the surface on the display panel unit 30 side of the polarizing layer 313 is referred to as an output surface 310b.

  Each element constituting the transparent layer 300 is made of, for example, a material having as little optical loss as possible and having as little optical phase difference as possible inside each element. Specifically, it is preferable to reduce the optical loss of the transparent layer 300 so that the light transmittance exceeds 95%. Further, it is preferable that the optical phase difference does not substantially exist inside the transparent layer 300.

  For example, the HC layer 301 protects the surface of the transparent substrate 302 from contact with the prism lens of the second prism sheet 23. The HC layer 301 is formed, for example, by applying an acrylic resin to the surface of the transparent substrate 302. As a material of the transparent substrate 302, for example, PET (polyethylene terephthalate), TAC (triacetyl cellulose), COP (cycloolefin polymer), or PMMA (polymethyl methacrylate) which is an acrylic resin can be used. The transparent adhesive layer 303 adheres the transparent substrate 302 to the incident surface 310a. As the transparent adhesive layer 303, for example, an acrylic resin adhesive can be used.

  The reflective layer 311 transmits the P-polarized component of the light incident from the incident surface 310a to the polarizing layer 313 side, and reflects the S-polarized component to the second prism sheet 23 side. The transparent adhesive layer 312 adheres the reflective layer 311 to the polarizing layer 313. The transparent adhesive layer 312 does not inhibit the transmission of each polarization component of light. The polarizing layer 313 transmits the P-polarized component of the light transmitted through the reflective layer 311 and the transparent adhesive layer 312 to the emission surface 310b side, and absorbs other polarized components. The S-polarized light component reflected by the reflective layer 311 is reflected by, for example, the prism surface of the second prism sheet 23 or the reflective sheet 13 and reaches the reflective polarizing plate 131 again. By repeating such reflection, the S-polarized component is eventually converted into a P-polarized component and is transmitted through the reflective polarizing layer 310. Thus, the luminance of the liquid crystal display device 1 can be improved by effectively utilizing the S-polarized component and the P-polarized component included in the light from the backlight unit 10.

  The backlight unit 10 and the display panel unit 30 are assembled by, for example, fixing the end portions via an adhesive, a pressure-sensitive adhesive, or a spacer, or fixing with an unshown bezel. The assembled liquid crystal display device 1 is used in a state of being incorporated in a housing 201 of a smartphone 200, for example, as shown in FIG. In addition, the liquid crystal display device 1 can be used as a display for various electronic devices such as a tablet terminal, a mobile phone, a notebook type PC, an electronic dictionary, or a television device, or an AV device.

  Here, as shown in FIG. 2, a plane including the ridge line of each prism lens formed on the second prism sheet 23 is defined as a prism surface 23a. Further, a gap between the incident surface 310a of the reflective polarizing layer 310 and the prism surface 23a is defined as G, and a thickness of the transparent layer 300 is defined as H.

  The gap G is locally reduced due to the bending caused by the external force of the second prism sheet 23 or the reflective polarizing plate 31 and the bending or warping of the second prism sheet 23 or the reflective polarizing plate 31 itself. Sometimes. When the gap G is locally reduced to a predetermined distance or less, the interference fringes described with reference to FIG. 8 may occur. However, the reflective polarizing plate 31 according to this embodiment includes the transparent layer 300 between the reflective polarizing layer 310 and the second prism sheet 23. Therefore, for example, even when the second prism sheet 123 or the like is bent by an external force, the gap G can be kept larger than at least the thickness H. Therefore, the generation of interference fringes can be reduced or prevented.

[Example]
The detailed configuration and operation of the liquid crystal display device 1 will be described with reference to the following embodiments. However, the scope of the invention is not limited to the configuration disclosed in this embodiment.

  FIG. 4 shows a result of producing liquid crystal display devices 1 having different thicknesses H of the transparent layer 300 and visually evaluating the generation level of interference fringes. This evaluation is made up of five types of liquid crystal displays: (1) no transparent layer 300 (H = 0 μm), (2) H = 10 μm, (3) H = 25 μm, (4) H = 37 μm, (5) H = 59 μm. Device 1 was targeted. In any one of (1) to (5), as the first prism sheet 22, an acrylic resin prism lens is formed on a polyester base material at a pitch of 24 μm, and the back surface of the base material is smooth and has a total thickness of 65 μm. A prism sheet was used. In any of (1) to (5), as the second prism sheet 23, an acrylic resin prism lens is formed on a polyester base material at a pitch of 24 μm, and a mat layer is provided on the back surface of the base material. A prism sheet having a total thickness of 70 μm was used.

  In (2), an HC layer 301 is not provided, and a 5 μm-thick transparent base material 302 formed of PET and a 5 μm-thick transparent adhesive layer 303 (glue) formed of an acrylic resin are used. The provided film was used as the transparent layer 300.

  In (3), an HC layer 301 is not provided, and a 20 μm thick transparent base material 302 formed of PMMA and a 5 μm thick transparent adhesive layer 303 (glue) formed of an acrylic resin are used. The provided film was used as the transparent layer 300.

  In (4), an HC layer 301 having a thickness of 7 μm formed of an acrylic resin, a transparent substrate 302 having a thickness of 25 μm formed of TAC, and a thickness of 5 μm formed of an acrylic resin. A transparent layer 300 was used as a transparent layer 300.

  In (5), an HC layer 301 having a thickness of 7 μm formed of an acrylic resin, a transparent substrate 302 having a thickness of 40 μm formed of TAC, and a thickness of 12 μm formed of an acrylic resin. A transparent layer 300 was used as a transparent layer 300.

  “Transmittance” in FIG. 4 is the transmittance of the transparent layer 300. In (1), since there is no transparent layer 300, the transmittance is 100%. Also in (2) to (5), the transmittance was approximately 100%.

  “N / R” in FIG. 4 is a result of visually evaluating the level of interference fringes by applying an external force to the liquid crystal display device 1 of (1) to (5). In (1) to (3), the generation of interference fringes was not sufficiently prevented (NG). On the other hand, in (4) and (5), the interference fringes were hardly noticeable, and a good prevention effect was obtained (OK).

  The level of interference fringes was evaluated in five stages from 1 (bad) to 5 (light), and “NG” was given below level 4 and “OK” was given above level 4. FIG. 5 is a graph showing the relationship between the interference fringe level and the thickness H of the transparent layer 300. The sampling point of the thickness H for creating the graph includes the thickness H of (1) to (5) shown in FIG. The graph is an approximate curve of the level evaluated at each sampling point. Thickness H = 0 μm was defined as a generation level 1. The interference fringe level rose steeply from around the thickness H = 10 μm, exceeded level 4 near the thickness H = 30 μm, and asymptotically approached level 5 thereafter.

  From this graph, it can be seen that the interference fringes are better prevented as the thickness H increases. Further, in the vicinity of the thickness H = 30 μm, the level of the interference fringes exceeds level 4, which is a criterion of the judgment standard. Accordingly, in this embodiment, the generation of interference fringes can be reduced or prevented by providing at least the transparent layer 300, and more appropriate effects can be obtained by setting the thickness H of the transparent layer 300 to about 30 μm or more. The conclusion that it plays is obtained.

[Comparison example with other methods]
Next, a comparative example of the configuration disclosed in the present embodiment and another method for reducing or preventing interference fringes will be described with reference to FIG.

As other methods, the following (I) to (IV) were adopted.
(I) In the liquid crystal display device 1, a scattering agent is added to the transparent adhesive layer 312 of the reflective polarizing layer 310 without providing the transparent layer 300. In this method, since the transparent adhesive layer 312 to which the scattering agent is added scatters the light and darkness of the interference fringes, the interference fringes are difficult to visually recognize.

(II) In the liquid crystal display device 1, the transparent layer 300 is not provided, and the surface of the polarizing plate 33 is subjected to scattering treatment (for example, antiglare treatment) to form a diffusion layer. In this method, since the diffusion layer scatters the light and darkness of the interference fringes, the interference fringes are difficult to visually recognize.

(III) In the liquid crystal display device 1, the transparent layer 300 is not provided, and the surface of the reflective polarizing layer 310 on the second prism sheet 23 side (that is, the reflective surface 310a) is subjected to scattering treatment (for example, antiglare treatment) to form a diffusion layer. To do. In this method, since light transmitted through the reflective layer 311 and light reflected by the reflective layer 311 are scattered by the diffusion layer, generation of interference fringes can be prevented.

(IV) In the liquid crystal display device 1, the transparent layer 300 is not provided, and a diffusion sheet is disposed between the reflective polarizing layer 310 and the second prism sheet 23. In this method, light incident on the reflective polarizing layer 310 from the second prism sheet 23 and light reflected on the reflective polarizing layer 310 and incident on the second prism sheet 23 are scattered by the diffusion sheet. Generation of interference fringes can be prevented.

  A liquid crystal display device employing the methods (I) to (IV) and a liquid crystal display device 1 employing the method according to the present embodiment in which the transparent layer 300 is provided on the incident surface 310a of the reflective polarizing layer 310 are manufactured. The effect of avoiding interference fringes and the luminance change rate of the display were evaluated. These liquid crystal display devices have the same configuration except for the portions described above for (I) to (IV). The luminance change rate is the luminance of a liquid crystal display device manufactured without employing any of the methods (I) to (IV) and this embodiment, that is, a liquid crystal display device having a configuration excluding the transparent layer 300 in FIG. The rate of change relative to the standard.

  As a result of the evaluation, in the liquid crystal display device employing the methods (I) and (II), an effect of slightly reducing interference fringes was obtained. However, in the liquid crystal display device employing the method (I), the luminance change rate was −6% or more, and in the liquid crystal display device employing the method (II), the luminance change rate was −5% or more.

  Further, in the liquid crystal display device adopting the methods (III) and (IV), interference fringes could be almost completely avoided. However, in the liquid crystal display device employing the method (III), the luminance change rate was −5% or more, and in the liquid crystal display device employing the method (IV), the luminance change rate was −10% or more.

  The liquid crystal display device 1 employing the method of the present embodiment was able to avoid interference fringes almost completely, particularly when the thickness H was 30 μm or more. Further, the luminance change rate was approximately 0% (no luminance change). That is, according to the liquid crystal display device 1 according to the present embodiment, the generation of interference fringes can be reduced or prevented without lowering the luminance.

The configuration disclosed in the above embodiment can be modified in various ways.
For example, in the above embodiment, the transmissive liquid crystal display device 1 is disclosed as an example of a display device including the reflective polarizing plate 31. However, the reflective polarizing plate 31 may be used as an optical element of a reflective liquid crystal display device, a transflective liquid crystal display device, or other types of display devices that do not use liquid crystal.

  The configuration of the reflective polarizing layer 310 is not limited to that disclosed in the above embodiment. As the reflective polarizing layer 310, a circularly polarized light separation type structure or a wire grid type structure may be used.

  The configuration of the transparent layer 300 is not limited to that disclosed in the above embodiment. For example, the transparent layer 300 may not include the HC layer 301. The effect that the transparent layer 300 reduces or prevents the generation of interference fringes is mainly due to the thickness H of the transparent layer 300. Therefore, even when the transparent layer 300 does not include the HC layer 301, the generation of interference fringes can be reduced or prevented.

  The optical elements provided in the liquid crystal display device 1 are not limited to those shown in FIG. In addition to what is shown in FIG. 7, the liquid crystal display device 1 may include a further optical element or may not include a part of the optical elements.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 10 ... Backlight unit, 11 ... Light source, 12 ... Light guide, 13 ... Reflection sheet, 20 ... Optical element group, 21 ... Diffusing sheet, 22 ... 1st prism sheet, 23 ... 2nd prism Sheet, 23a ... Prism surface, 30 ... Display panel unit, 31 ... Reflective polarizing plate, 32 ... Liquid crystal panel, 33 ... Polarizing plate, 300 ... Transparent layer, 301 ... HC layer, 302 ... Transparent substrate, 303 ... Transparent adhesive Layer 310, reflective polarizing layer, 310a, incident surface, 310b, outgoing surface, 311 ... reflective layer, 312 ... transparent adhesive layer, 313 ... polarizing layer.

Claims (18)

A display panel unit facing a prism sheet arranged on the light source side,
A display panel that controls light transmission;
The light source side incident surface and the display panel side emission surface have a first polarization component of light incident from the incident surface transmitted to the emission surface and the light incident from the incident surface. A reflective polarizing layer that reflects a second polarization component orthogonal to the one polarization component toward the light source;
The second polarized light that is provided in close contact with the incident surface, transmits the first polarized component and the second polarized component of the light from the light source side to the incident surface side, and is reflected by the reflective polarizing layer. A transparent layer that transmits the polarization component to the light source side;
With
The transparent layer has a thickness of 30 μm or more and 59 μm or less .
Display panel unit.   The transparent layer prevents the occurrence of interference fringes by preventing the gap between the prism surface of the prism sheet and the incident surface of the reflective polarizing layer from becoming smaller than 30 μm.
  The display panel unit according to claim 1. The reflective polarization layer reflects the second polarization component of light incident from the incident surface, and transmits the first polarization component of light that is attached to the display panel and transmitted through the reflection layer. A polarizing layer that absorbs other polarizing components, and a first adhesive layer that adheres the reflective layer and the polarizing layer,
The display panel unit according to claim 1 or 2. The transparent layer includes a transparent base material, and a transparent second adhesive layer that adheres the transparent base material to the reflective polarizing layer.
The display panel unit according to any one of claims 1 to 3. The transparent layer further includes a hard coat layer provided on the surface of the transparent substrate,
The transparent substrate is disposed between the reflective polarizing layer and the hard coat layer,
The display panel unit according to claim 4 . The light transmittance of the transparent layer is 95% or more.
The display panel unit according to any one of claims 1 to 5 . A backlight unit having a light source and a light guide that takes in light from the light source and emits the light from an emission surface;
A display panel that controls light transmission;
A light incident surface on the backlight unit side and an output surface on the display panel side; the first polarization component of light incident from the incident surface is transmitted to the output surface; A reflective polarizing layer that reflects the second polarized light component orthogonal to the first polarized light component toward the backlight unit;
The first polarization component and the second polarization component of the light from the backlight unit side that are provided in close contact with the incident surface are transmitted to the incident surface side and reflected by the reflective polarizing layer. A transparent layer that transmits the second polarization component to the backlight unit side;
A prism sheet having a prism surface on which a prism lens is formed, and disposed between the transparent layer and the light guide so that the prism surface faces the transparent layer;
With
The transparent layer has a thickness of 30 μm or more and 59 μm or less .
Display device.   The transparent layer prevents the occurrence of interference fringes by preventing the gap between the prism surface of the prism sheet and the incident surface of the reflective polarizing layer from becoming smaller than 30 μm.
  The display device according to claim 7.   A backlight unit having a light source and a light guide that takes in light from the light source and emits the light from an emission surface;
  A display panel that controls light transmission;
  A light incident surface on the backlight unit side and an output surface on the display panel side; the first polarization component of light incident from the incident surface is transmitted to the output surface; A reflective polarizing layer that reflects the second polarized light component orthogonal to the first polarized light component toward the backlight unit;
  The first polarization component and the second polarization component of the light from the backlight unit side that are provided in close contact with the incident surface are transmitted to the incident surface side and reflected by the reflective polarizing layer. A transparent layer that transmits the second polarization component to the backlight unit side;
  A prism sheet having a prism surface on which a prism lens is formed, and disposed between the transparent layer and the light guide;
  With
  The transparent layer has a thickness of 30 μm or more,
  The transparent layer and the prism surface face each other without any other member,
  There is substantially no optical retardation inside the transparent layer,
  Display device.   A backlight unit having a light source and a light guide that takes in light from the light source and emits the light from an emission surface;
  A display panel that controls light transmission;
  A light incident surface on the backlight unit side and an output surface on the display panel side; the first polarization component of light incident from the incident surface is transmitted to the output surface; A reflective polarizing layer that reflects the second polarized light component orthogonal to the first polarized light component toward the backlight unit;
  The first polarization component and the second polarization component of the light from the backlight unit side that are provided in close contact with the incident surface are transmitted to the incident surface side and reflected by the reflective polarizing layer. A transparent layer that transmits the second polarization component to the backlight unit side;
  A prism sheet having a prism surface on which a prism lens is formed, and disposed between the transparent layer and the light guide so that the prism surface faces the transparent layer;
  A diffusion sheet disposed between the prism sheet and the light guide, and diffusing light from the light guide;
  With
  The transparent layer has a thickness of 30 μm or more.
  Display device.   A backlight unit having a light source and a light guide that takes in light from the light source and emits the light from an emission surface;
  A display panel that controls light transmission;
  A light incident surface on the backlight unit side and an output surface on the display panel side; the first polarization component of light incident from the incident surface is transmitted to the output surface; A reflective polarizing layer that reflects the second polarized light component orthogonal to the first polarized light component toward the backlight unit;
  The first polarization component and the second polarization component of the light from the backlight unit side that are provided in close contact with the incident surface are transmitted to the incident surface side and reflected by the reflective polarizing layer. A transparent layer that transmits the second polarization component to the backlight unit side;
  A prism sheet having a prism surface on which a prism lens is formed, and disposed between the transparent layer and the light guide;
  With
  The transparent layer has a thickness of 30 μm or more,
  The transparent layer and the prism surface face each other without any other member.
  Display device.   The transparent layer has a thickness of 30 μm or more and 59 μm or less.
  The display device according to claim 9. The reflective polarization layer reflects the second polarization component of light incident from the incident surface, and transmits the first polarization component of light that is attached to the display panel and transmitted through the reflection layer. A polarizing layer that absorbs other polarizing components, and a first adhesive layer that adheres the reflective layer and the polarizing layer,
The display device according to claim 7 . The transparent layer is disposed in a gap between the reflective layer and the prism surface;
The display device according to claim 13 . A gap is formed between the transparent layer and the prism surface,
Display device according to any one of claims 7 to 14. The transparent layer includes a transparent base material, and a transparent second adhesive layer that adheres the transparent base material to the reflective polarizing layer.
Display device according to any one of claims 7 to 15. The transparent layer further includes a hard coat layer provided on the surface of the transparent substrate,
The transparent substrate is disposed between the reflective polarizing layer and the hard coat layer,
The display device according to claim 16 . The light transmittance of the transparent layer is 95% or more.
Display device according to any one of claims 7 to 17.

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