Display using natural light

Abstract

To provide an external light utilizing display medium that exhibits excellent visibility.SOLUTION: Provided is an external light utilizing display medium 1a, 1b comprising a light diffusion control layer 11, a display layer 13 and a reflection layer 12, the light diffusion control layer 11 including a regular internal structure provided with a plurality of relatively high refractive index regions in a relatively low refractive index region, the reflection layer 12 including a rugged structure when at least one cross section having been cut in the thickness direction is seen. When a beam proceeding on a beam progression plane and having a prescribed angle of incidence is radiated upon an incidence plane while scanning along the intersection of the beam progression plane and the incidence plane, the percentage of a beam that satisfies the condition of expression (1) or expression (2) is 50% or greater. (1): θid<θdd-≤θod≤θdd+; (2): θdd-≤θid≤θdd+<θod.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an external light-utilizing display device that utilizes light incident from the outside to achieve a predetermined display function. [Background technology]

[0002] Conventionally, displays formed by printing characters or images on a reflective surface, or by attaching a transparent or semi-transparent film on which characters or images are printed to a reflective surface, have been used as signs or labels. Some displays, such as liquid crystal display devices and electronic paper, are provided with a reflective layer.

[0003] In such external light-utilizing displays, the display surface is illuminated by a light source such as indoor lighting or the sun, or an auxiliary light source provided on the display surface side of the display, and the light from these light sources is reflected by a reflective surface or reflective layer, making the display visible.

[0004] In an external light-utilizing display, the positional relationship between the light source and the viewer is not usually constant due to the use of an external light source. As a result, depending on the position of the light source, sufficient light does not reach the viewer, which can lead to problems such as reduced visibility and inability to illuminate the entire display brightly.

[0005] In order to solve the above problems, it is conceivable to incorporate a light diffusion plate into the display. However, simply incorporating a general light diffusion plate will not provide sufficient diffusion required for good visibility, and when attempting to achieve wide diffusion, there is a problem that light loss occurs due to stray light and backscattering, impairing image clarity. From the viewpoint of solving these problems, in an external light-utilizing display, it has been considered to provide a light diffusion control layer between the viewer-side surface and the reflective layer, which can transmit and diffuse incident light within a predetermined incident angle range in a strong and low light loss state (for example, Patent Document 1). Due to the presence of the light diffusion control layer, the light reflected by the reflective layer is appropriately diffused, and the decrease in visibility depending on the position of the light source is reduced. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6250648 Summary of the Invention [Problem to be solved by the invention]

[0007] Although the use of the above-mentioned light diffusion control layer achieves some improvement in visibility, there is a need to achieve even brighter and more uniform visibility.

[0008] The present invention has been made in view of the above circumstances, and has an object to provide an external light-utilizing display that exhibits excellent visibility. [Means for solving the problem]

[0009] In order to achieve the above object, firstly, the present invention provides an external light utilization type display device comprising a light diffusion control layer, a display layer and a reflective layer, which are laminated in the order of the light diffusion control layer, the display layer and the reflective layer, or the display layer, the light diffusion control layer and the reflective layer, wherein the light diffusion control layer has a regular internal structure comprising a plurality of regions with a relatively high refractive index within a region with a relatively low refractive index, the reflective layer has an uneven structure when at least one cross section cut in the thickness direction is viewed, the surface of the uneven structure constitutes a reflective surface, the surface located distal to the reflective layer in the external light utilization type display device is defined as an incident surface, a surface including a normal to the incident surface and a diffusion central axis of the light diffusion control layer is defined as a light ray proceeding surface, and when the angle formed by the light ray proceeding surface and the normal to the incident surface is expressed as With respect to the normal to the incident surface, a negative sign is given when light enters from or exits toward the main inclination direction of the uneven surface, and a positive sign is given in the opposite case. The main inclination direction of the uneven surface means a more frequent inclination direction when, for a cross section of the uneven surface obtained by cutting the uneven surface at the light ray traveling plane, the position in the thickness direction of the reflective layer in the uneven surface is differentiated with respect to the position in the in-plane direction of the reflective layer, and the inclination directions of the minute surfaces in the uneven surface are classified according to whether the differential value is a positive value or a negative value. In this case, when a light ray traveling on the light ray traveling plane and having a predetermined incident angle is irradiated onto the incident surface while scanning along the intersection line between the light ray traveling plane and the incident surface, the proportion of the light rays that satisfy the condition of the following formula (1) or the following formula (2) is 50% or more. θ id <θ dd- ≦θ od ≦θ dd+ …(1) θ dd- ≦θ id ≦θ dd+ <θ od …(2) (The above θ id means an angle of the light ray traveling from the incident surface toward the reflective layer with respect to the normal line of the incident surface immediately after the light ray enters the light diffusion control layer, and is −35° or −25°. (The above θ od means an angle of the light ray reflected by the reflective layer toward the incident surface, with respect to the normal to the incident surface immediately after the light ray enters the light diffusion control layer.) (The above θ dd- and θ dd+ are the lower limit and upper limit angles of the diffusion angle range of the light diffusion control layer, respectively, converted into angles in the light diffusion control layer, taking into consideration refraction occurring at the interface between air and the light diffusion control layer, and the diffusion angle range is the range of incidence angles in which, when light is sequentially incident on one surface of the light diffusion control layer alone at incidence angles in the range of -90° to 90° and the haze value of the transmitted light emerging from the other surface is measured, the haze value is 90% or more. The present invention provides an external light-utilizing display device characterized by the above-mentioned (Invention 1).

[0010] The external light utilization display device of the above invention (Invention 1) has the above-mentioned light diffusion control layer and the above-mentioned reflective layer laminated so as to satisfy the conditions related to the above formula (1) or formula (2), thereby making it possible to effectively reflect incident light toward the viewer, and as a result, the viewer can view a bright and uniform display.

[0011] Secondly, the present invention provides an external light utilization type display device comprising an auxiliary light source, a light diffusion control layer, a display layer and a reflective layer, which are laminated in the following order: the auxiliary light source, the light diffusion control layer, the display layer and the reflective layer, or the auxiliary light source, the display layer, the light diffusion control layer and the reflective layer, wherein the auxiliary light source irradiates light onto the display layer, the light diffusion control layer has a regular internal structure comprising a plurality of regions having a relatively high refractive index within a region having a relatively low refractive index, the reflective layer has an uneven structure when at least one cross section cut in the thickness direction is viewed, and a surface of the uneven structure constitutes a reflective surface, the surface of the external light utilization type display device that is located distal to the reflective layer is an incident surface, a surface including a normal to the incident surface and the diffusion central axis of the light diffusion control layer is a light ray proceeding surface, and the light ray proceeding surface is a surface of the external light utilization type display device that is a light ray proceeding surface. When expressing the angle between a light ray traveling on a surface and a normal to the incident surface, a negative sign is used when the light ray enters from or exits toward the main inclination direction of the uneven structure with respect to the normal to the incident surface, and a positive sign is used in the opposite case. The main inclination direction of the uneven surface means a more frequent inclination direction when, for a cross section of the uneven structure obtained by cutting the uneven structure at the light ray traveling surface, the position in the thickness direction of the reflective layer in the uneven structure is differentiated by the position in the in-plane direction of the reflective layer, and the inclination directions of the minute surfaces in the uneven structure are classified depending on whether the differential value is a positive value or a negative value. When the incident surface is irradiated with a light ray originating from the auxiliary light source traveling on the light ray traveling surface, the proportion of the light rays that satisfy the condition of the following formula (1) or the following formula (2) is 50% or more. θ id <θ dd- ≦θ od ≦θ dd+ …(1) θ dd- ≦θ id ≦θ dd+ <θ od …(2) (The above θ id means an angle of a light ray originating from the auxiliary light source traveling from the incident surface toward the reflective layer, with respect to a normal line to the incident surface immediately after the light ray enters the light diffusion control layer.) (The above θ od means an angle of a light ray originating from the auxiliary light source, which is reflected by the reflective layer and directed toward the incident surface, with respect to the normal to the incident surface immediately after entering the light diffusion control layer. (The above θ dd- and θ dd+ are angles obtained by converting the lower limit and upper limit of the diffusion angle range of the light diffusion control layer into angles in the light diffusion control layer, taking into consideration refraction occurring at the interface between air and the light diffusion control layer, and the diffusion angle range is the range of incidence angles in which, when light is sequentially incident on one surface of the light diffusion control layer alone at incidence angles in the range of -90° to 90° and the haze value of the transmitted light emerging from the other surface is measured, the haze value is 90% or more.) The present invention provides an external light-utilizing display device characterized by the above-mentioned (Invention 2).

[0012] The external light utilization display device of the above invention (Invention 2) has the above-mentioned light diffusion control layer and the above-mentioned reflective layer laminated so as to satisfy the conditions related to the above formula (1) or formula (2), thereby making it possible to effectively reflect light from the auxiliary light source toward the viewer, and as a result, the viewer can view a bright and uniform display.

[0013] In the above inventions (Inventions 1 and 2), it is preferable that the uneven structure, when viewed in at least one cross section cut in the thickness direction, is a sawtooth structure in which first inclined surfaces having a predetermined inclination and second inclined surfaces having an inclination different from that of the first inclined surfaces are arranged alternately (Invention 3).

[0014] In the above inventions (Inventions 1 and 2), when the reflective layer is viewed in a plane, it is preferable that the total area of ​​the first inclined surfaces is larger than the total area of ​​the second inclined surfaces, and when at least one cross section cut through the reflective layer in the thickness direction is viewed, the angle of the normal to the first inclined surfaces is greater than or equal to -40° and less than or equal to -1° with respect to the normal to the incident surface (Invention 4).

[0015] In the above inventions (Inventions 1 to 4), the external light-utilizing display satisfies the formula (1), and the θ dd- is equal to or greater than -25° and less than 0°, dd+ It is preferable that the angle is 0° or more and 25° or less (Invention 5).

[0016] In the above inventions (Inventions 1 to 4), the external light-utilizing display satisfies the formula (2), and the θ dd- is equal to or greater than -38° and less than -13°, dd+ It is preferable that the angle is not less than -13° and not more than 19° (Invention 6). Effect of the Invention

[0017] The external light-utilizing display according to the present invention exhibits excellent visibility. [Brief description of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view of an external light-utilizing display according to one embodiment of the present invention. [Diagram 2] FIG. 11 is a cross-sectional view of an external light-utilizing display according to another embodiment of the present invention. [Diagram 3] FIG. 10 is a diagram for explaining a schematic representation of the angle of a light ray. [Figure 4] FIG. 2 is a diagram for illustrating conditions according to one embodiment of the present invention. [Diagram 5] FIG. 2 is a cross-sectional view of an example of a reflective layer in one embodiment of the present invention. [Figure 6] FIG. 13 is a diagram showing the variable angle haze value of the light diffusion control layer used in the examples. [Figure 7] FIG. 13 is a diagram showing the measurement results of the diffuse light reflectance of an ambient light-utilizing display sample produced in an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows a cross-sectional view of an external light-utilizing display according to one embodiment of the present invention. The external light-utilizing display 1a, 1b according to this embodiment shown in FIG. 1 includes a light diffusion control layer 11, a display layer 13, and a reflective layer 12. In the external light-utilizing display 1a, 1b according to this embodiment, the layers are stacked in the order of the light diffusion control layer 11, the display layer 13, and the reflective layer 12 (FIG. 1(a)), or in the order of the display layer 13, the light diffusion control layer 11, and the reflective layer 12 (FIG. 1(b)). The external light-utilizing display 1a, 1b according to this embodiment may include any layer other than these three layers at any position.

[0020] FIG. 2 shows a cross-sectional view of an external light-utilizing display according to another embodiment of the present invention. The external light-utilizing display 2a, 2b according to this embodiment shown in FIG. 2 includes an auxiliary light source 14, a light diffusion control layer 11, a display layer 13, and a reflective layer 12. In the external light-utilizing display 2a, 2b according to this embodiment, the layers are stacked in the order of the auxiliary light source 14, the light diffusion control layer 11, the display layer 13, and the reflective layer 12 (FIG. 2(a)), or in the order of the auxiliary light source 14, the display layer 13, the light diffusion control layer 11, and the reflective layer 12 (FIG. 2(b)). The external light-utilizing display 2a, 2b according to this embodiment may include any layer other than these four layers at any position.

[0021] In the external light-utilizing display according to this embodiment, the light diffusion control layer 11 has a regular internal structure with a plurality of regions with a relatively high refractive index within a region with a relatively low refractive index. The reflective layer 12 has an uneven structure when at least one cross section cut in the thickness direction is viewed, and the surface of the uneven structure constitutes a reflective surface. The auxiliary light source 14 irradiates light onto the display layer 13.

[0022] The external light utilization type display bodies 1a and 1b according to this embodiment shown in FIG. 1 and the external light utilization type display bodies 2a and 2b according to this embodiment shown in FIG. 2 are configured to satisfy the conditions related to the following formula (1) or the following formula (2). θ id <θ dd-≦θ od ≦θ dd+ …(1) θ dd- ≦θ id ≦θ dd+ <θ od …(2)

[0023] In explaining the above formulas (1) and (2), in this specification, the surface of the ambient light display 1a, 1b, 2a, 2b that is located farther from the reflective layer 12 is defined as the incident surface.

[0024] In this specification, the light ray traveling plane is defined as a plane including the normal to the incident plane and the central diffusion axis of the light diffusion control layer 11. Here, the central diffusion axis refers to an axis about which the diffusion characteristics are substantially symmetrical, and can be estimated based on the diffusion performance grasped by measuring the variable haze of the light diffusion control layer 11 or the like.

[0025] Furthermore, in this specification, the angle between the light ray traveling on the light ray traveling surface and the normal to the incident surface is expressed according to the following rules: When the light ray enters from or exits toward the main inclination direction of the concave-convex structure with respect to the normal to the incident surface, a negative sign is used, and when the light ray exits from the main inclination direction of the concave-convex structure, a positive sign is used.

[0026] FIG. 3(a) shows examples of these rays (ray A and ray B). In particular, ray A is shown as having entered from the main inclination direction side of the concave-convex structure when the normal to the incident surface is used as a reference. Here, when the absolute value of the angle between ray A and the normal to the incident surface is 60°, the angle is given a negative sign and expressed as "-60°". On the other hand, ray B is shown as attempting to exit on the side opposite to the main inclination direction of the concave-convex structure when the normal to the incident surface is used as a reference. Here, when the absolute value of the angle between ray B and the normal to the incident surface is 45°, the angle is expressed as "45°" or "+45°" as it is or with a positive sign.

[0027] The "main inclination direction of the uneven surface" is determined as follows. First, a cross section of the uneven structure obtained by cutting the uneven structure at the light traveling plane is assumed. FIG. 3(b) shows an example of the cross section. Next, in the uneven structure 121 included in the cross section, the position in the thickness direction of the reflective layer 12 (in FIG. 3(b), the vertical direction on the paper) is differentiated with respect to the position in the in-plane direction of the reflective layer 12 (in FIG. 3(b), the horizontal direction on the paper). The differential value obtained by this is a positive value or a negative value (and further, although not shown, 0 as a switching point between positive and negative values) depending on the direction of inclination in the uneven structure 121, as shown in FIG. 3(b). Then, when the inclination direction of the minute surface in the uneven structure 121 is classified according to whether the differential value is a positive value or a negative value, the more frequent inclination direction is determined as the "main inclination direction of the uneven surface". In the case of FIG. 3(b), since the positive values ​​are more frequent, the side of the inclined surface marked "positive" is the "main inclination direction of the uneven surface."

[0028] Based on the above, in the external light utilization type display bodies 1a and 1b according to this embodiment shown in FIG. 1, when a light ray traveling along the light ray traveling surface and having a predetermined incident angle is irradiated onto the incident surface while scanning along the intersection line between the light ray traveling surface and the incident surface, the proportion of the light ray that satisfies the condition of the above formula (1) or (2) is 50% or more.

[0029] Here, in the above formula (1) and formula (2), θ id means the angle of a light ray traveling from the incident surface toward the reflective layer 12 with respect to the normal line of the incident surface immediately after the light ray enters the light diffusion control layer 11. In particular, in the ambient light display devices 1a and 1b shown in FIG. id The specific angle is −35° or −25°. That is, the ambient light display 1a and 1b shown in FIG. id When a light beam is irradiated onto the incident surface so that the angle θ is −35° or −25°, there are cases where the condition of either of the above-mentioned formula (1) or formula (2) is satisfied. idWhen the light is scanned along the intersection line between the light beam traveling plane and the incident plane while maintaining θ = -35° or -25°, 50% or more of the irradiated light beams satisfy either the condition of the above formula (1) or formula (2). id = It is sufficient to achieve a ratio of 50% or more at either -35° or -25°.

[0030] In this specification, the angle of the light ray "immediately after it is incident" refers to the angle before the light ray is diffused by the action of the light diffusion control layer 11. Normally, when a light ray is incident on the light diffusion control layer 11 from the air or a layer adjacent to the light diffusion control layer 11, the light is refracted as the light ray passes between the layers, and the light is diffused while passing through the inside of the light diffusion control layer 11. However, it can be considered that only refraction occurs "immediately after it is incident", and no diffusion occurs.

[0031] In addition, the above θ od means the angle of a light ray reflected by the reflective layer 12 and heading toward the incident surface, with respect to the normal to the incident surface immediately after the light ray enters the light diffusion control layer 11. od is at a predetermined angle (in the light-utilizing display bodies 1a and 1b shown in FIG. 1, θ id = -35° or -25°), is reflected by the reflective layer 12 and returns toward the direction of the incident surface, and is expressed as the angle at which the light ray is incident on the light diffusion control layer 11 immediately after it enters the light diffusion control layer 11.

[0032] Furthermore, the above θ dd- and θ dd+ are the lower limit and upper limit angles of the diffusion angle range of the light diffusion control layer 11, converted into angles in the light diffusion control layer 11, taking into consideration refraction occurring at the interface between air and the light diffusion control layer 11. Here, the above-mentioned diffusion angle range is the range of incidence angles in which, when light is sequentially incident on one surface of the light diffusion control layer 11 alone (i.e., a surface on which no other layers are laminated) at incidence angles in the range of -90° to 90° and the haze value of the transmitted light emerging from the other surface is measured, the haze value is 90% or more.

[0033] On the other hand, in the external light utilization type display bodies 2a and 2b according to this embodiment shown in FIG. 2, when light rays originating from the auxiliary light source traveling along the light ray traveling plane are irradiated onto the incident plane, the proportion of the light rays that satisfy the above-mentioned formula (1) or formula (2) is 50% or more.

[0034] In the ambient light display bodies 2a and 2b according to this embodiment shown in FIG. id , θ od , θ dd- and θ dd+ The definition of is basically the same as that of the ambient light type display 1a and 1b shown in FIG. id is not specified to -35° or -25° in the ambient light-utilizing display bodies 2a and 2b shown in Fig. 2. Therefore, the ambient light-utilizing display bodies 2a and 2b have a ratio of 50% or more of light rays that are irradiated from the auxiliary light source 14 provided therein and travel along the light ray travel surface and that satisfy the condition of the above-mentioned formula (1) or formula (2).

[0035] Whether or not a certain ambient light-utilizing display satisfies the above formula (1) or (2) at the above ratio can be confirmed as follows. First, based on the diffusion angle range measured as described above for the light diffusion control layer alone and the refractive index of the light diffusion control layer, the lower and upper limit angles of the diffusion angle range are converted to angles in the light diffusion control layer (details will be described later), and the angle θ dd- and θ dd+ get.

[0036] Then, a light beam is irradiated at a predetermined incident angle onto the surface of the external light-utilizing display body facing the light diffusion control layer, and the angle of the outgoing light beam is measured in sequence.

[0037] In the case of an external light-utilizing display device that does not have an auxiliary light source, the incident angle is set to an angle θ idThe incident angle is set to be -35° or -25°. In addition, the light ray traveling surface and the incident surface (the surface located farther from the reflective layer in the external light-utilizing display body) assumed when the external light-utilizing display body is constructed are determined, and the above-mentioned incident point is changed along the intersection line between the light ray traveling surface and the above-mentioned incident surface.

[0038] On the other hand, in the case of an external light-utilizing display device having an auxiliary light source, the auxiliary light source is turned on to irradiate light rays.

[0039] Then, the angles measured in sequence are converted into angles in the light diffusion control layer, taking into consideration the refraction that occurs in the light path when the external light utilization type display is constructed, to obtain an angle θ id and angle θ od The angle θ for each ray obtained is id and angle θ od By calculating the ratio that satisfies the relationship of the above-mentioned formula (1) or formula (2), it can be determined whether the above-mentioned ratio is satisfied.

[0040] 1. Details of Equation (1) and Equation (2) The above formulas (1) and (2) will be explained in more detail below with reference to FIG.

[0041] Fig. 4(a) shows the relationship between light rays and the diffusion angle range (converted range) in the light diffusion control layer 11 when the condition of the above formula (1) is satisfied, and Fig. 4(b) shows the relationship between light rays and the diffusion angle range (converted range) in the light diffusion control layer 11 when the condition of the above formula (2) is satisfied. Note that these figures are cross-sectional views that show only the light diffusion control layer 11 in a schematic manner, and the reflective layer 12 is actually laminated directly or indirectly via another layer below the light diffusion control layer 11 in the plane of the drawing.

[0042] In FIGS. 4(a) and 4(b), the arrow indicated by “I” represents a ray of light that is incident from the incident surface side and passes through the light diffusion control layer 11. The angle between the ray of light I and the normal to the incident surface is θ idThe arrow indicated by "O" represents the light ray I that is reflected by the reflective layer 12 that is originally located in the downward direction of the paper, returns to the light diffusion control layer 11, and passes through the light diffusion control layer 11. The angle between the light ray O and the normal to the incident surface is θ od Furthermore, "D - " and "D + The range surrounded by the line marked with " " (the range marked with diagonal lines in the drawing) corresponds to the diffusion angle range of the light diffusion control layer 11. - The angle between the normal to the incident surface is θ dd- And line D + The angle between the normal to the incident surface is θ dd+ It becomes.

[0043] The above formula (1) is the angle θ id But the angle θ dd- and angle θ dd+ and the angle θ od In other words, as shown in FIG. 4(a), a light ray I originating from an external light source or an auxiliary light source 14 and incident on the light diffusion control layer 11 is reflected by a line D - and line D + After passing through the outside of the range surrounded by and and passing through the light diffusion control layer 11, the light ray O reflected by the reflective layer 12 travels along a line D. - and line D + This means that the light is emitted from the light diffusion control layer 11 through the area surrounded by the line D - and line D + The range surrounded by corresponds to the diffusion angle range, so the light rays passing through that range have a haze value of 90% or more when emitted, that is, are strongly diffused and transmitted. Therefore, after the light ray I passes through the light diffusion control layer 11 without light diffusion or with weak light diffusion, the light ray O is strongly diffused and transmitted and is emitted from the light diffusion control layer 11.

[0044] On the other hand, the above formula (2) is id is the angle θ dd- and angle θ dd+ The angle θ odThat is, as shown in FIG. 4(b), a light ray I originating from an external light source or an auxiliary light source 14 and incident on the light diffusion control layer 11 is reflected by a line D - and line D + After passing through the area surrounded by and and transmitting through the light diffusion control layer 11, the light ray O reflected by the reflective layer 12 travels along a line D - and line D + This means that the light ray I is emitted from the light diffusion control layer 11 by passing outside the range surrounded by and . In this case, after the light ray I is strongly diffused and transmitted through the light diffusion control layer 11, the light ray O is not strongly diffused again and is emitted from the light diffusion control layer 11 while maintaining the diffused state.

[0045] The external light-utilizing display bodies 1a, 1b and the external light-utilizing display bodies 2a, 2b according to the present embodiment satisfy the conditions of the above formula (1) or (2) at the above-mentioned predetermined ratio, respectively, and thus can effectively diffuse and reflect the light rays incident from an oblique direction to a viewer in the front direction. As a result, the viewer can view the display content of the display layer 13 with sufficient and uniform brightness. This prevents the light rays from being diffused twice before and after reflection by the reflective layer 12, and prevents the light rays from being diffused too much, resulting in a decrease in brightness or a loss of uniformity in the diffused light.

[0046] As described above, the diffusion angle range of the light diffusion control layer 11 is determined from the incident angle of light rays that satisfy a predetermined haze value among light rays irradiated from the air to the light diffusion control layer 11 alone. In other words, the diffusion angle range is defined based on the angle of light rays in the air. Meanwhile, the above formulas (1) and (2) in this embodiment are determined based on the angle θ in the light diffusion control layer 11. dd- and θ dd+ Therefore, the angle θ dd- and θ dd+ The upper and lower limit angles of the diffusion angle range are converted into the range of angles in the light diffusion control layer 11, taking into account the refraction occurring at the interface between air and the light diffusion control layer 11. Specifically, the conversion is performed using the following formula: θ dd-=arcsin{sin(θ d- )×1 / n} θ dd+ =arcsin{sin(θ d+ )×1 / n} In these formulas, θ d- and θ d+ respectively mean the lower and upper limit angles of the diffusion angle range of the light diffusion control layer 11. n means the refractive index of the light diffusion control layer 11.

[0047] In the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment, when light rays are irradiated as described above, the ratio of the light rays that satisfy the condition of the above formula (1) or (2) is 50% or more, but from the viewpoint of achieving even better visibility, the ratio is preferably 70% or more, and more preferably 90% or more. The upper limit of the ratio is not particularly limited and may be 100%.

[0048] When the ambient light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment satisfy the above formula (1), the angle θ dd- is preferably -25° or more, more preferably -22° or more, and further preferably -19° or more. dd- is preferably less than 0°, more preferably -3° or less, and even more preferably -6° or less. dd+ is preferably 0° or more, more preferably 3° or more, and further preferably 6° or more. dd+ is preferably 25° or less, more preferably 22° or less, and even more preferably 19° or less. By satisfying such an angle, the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment can achieve better visibility.

[0049] On the other hand, when the ambient light display devices 1a, 1b, 2a, and 2b according to the present embodiment satisfy the above formula (2), the angle θ dd-is preferably -38° or more, more preferably -37° or more, and further preferably -35° or more. dd- is preferably less than −13°, more preferably −16° or less, and even more preferably −19° or less. dd+ is preferably -13° or more, more preferably -10° or more, and further preferably -6° or more. dd+ is preferably 19° or less, more preferably 16° or less, and even more preferably 13° or less. By satisfying such an angle, the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment can achieve better visibility.

[0050] 2. Light diffusion control layer The light diffusion control layer 11 in this embodiment has a regular internal structure with multiple regions of relatively high refractive index within a region of relatively low refractive index, and as long as it exhibits the above-mentioned diffusion angle range as a result of this, there are no limitations on its internal structure, composition, etc.

[0051] The above-mentioned regular internal structure refers to an internal structure in which a plurality of regions with a relatively high refractive index are arranged with a certain regularity in a region with a relatively low refractive index. For example, when a cross section of the light diffusion control layer 11 cut along a plane parallel to the surface of the light diffusion control layer 11 is viewed, the internal structure refers to an internal structure in which regions with a relatively high refractive index are repeatedly arranged with a similar pitch in a region with a relatively low refractive index along at least one direction in the cross section. The regular internal structure here is distinguished from a phase separation structure in which one phase exists in another phase without clear regularity and a sea-island structure in which approximately spherical island components exist in a sea component, in that the regions with a relatively high refractive index extend in the thickness direction of the light diffusion control layer 11.

[0052] According to the above-mentioned regular internal structure, incident light within a predetermined range of incident angles on the surface of the light diffusion control layer 11 can be emitted while being strongly diffused with a predetermined opening angle. On the other hand, when the incident angle is outside the above-mentioned range, the light can be transmitted without being diffused, or can be emitted with weaker diffusion than the incident light within the range of incident angles.

[0053] From the viewpoint of facilitating the formation of the regular internal structure as described above, the light diffusion control layer 11 according to the present embodiment is preferably a layer obtained by curing a composition for a light diffusion control layer that contains a high refractive index component and a low refractive index component having a refractive index lower than that of the high refractive index component. As the high refractive index component, the low refractive index component, and other components contained in the composition for a light diffusion control layer, conventionally known components can be used. Then, the light diffusion control layer 11 can be formed by a conventionally known method.

[0054] The thickness of the light diffusion control layer 11 in this embodiment is preferably 30 μm or more, more preferably 45 μm or more, and even more preferably 60 μm or more. The thickness is preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 200 μm or less. When the thickness of the light diffusion control layer 11 is in this range, the external light utilization type display bodies 1a, 1b, 2a, and 2b according to this embodiment are likely to satisfy the condition of the above-mentioned formula (1) or formula (2).

[0055] 3.Reflective layer The reflective layer 12 in this embodiment is not particularly limited as long as it has an uneven structure when viewed at least one cross section cut in the thickness direction, the surface of the uneven structure forms a reflective surface, and as a result, the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to this embodiment satisfy the above formula (1) or formula (2) at a predetermined ratio. The reflective layer 12 in this embodiment has the above uneven structure, making it possible to reflect light rays incident from an oblique direction in the front direction. As a result, the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to this embodiment are more likely to satisfy the conditions of the above formula (1) or formula (2).

[0056] An example of the above-mentioned uneven structure is a sawtooth structure as shown in Fig. 5. Fig. 5 is a cross-sectional view showing at least one cross section of a reflective layer 12 having a sawtooth structure cut in the thickness direction. The reflective layer 12 includes a sawtooth structure 121, a support region 125 that supports the sawtooth structure 121, and a transparent region 124 laminated on the sawtooth structure 121. Furthermore, the sawtooth structure 121 has a structure in which a first inclined surface 122 having a predetermined inclination and a second inclined surface 123 having an inclination different from that of the first inclined surface 122 are alternately arranged.

[0057] In the reflective layer 12 having such a sawtooth structure 121, the sawtooth structure 121 has reflectivity to light rays, and can effectively reflect light rays obliquely incident from the surface side of the transparent region 124 toward the front direction. Note that the reflective layer 12 having the sawtooth structure 121 does not necessarily have to have the transparent region 124.

[0058] In the reflective layer 12 having the sawtooth structure 121, it is preferable that the first inclined surface 122 and the second inclined surface 123 have different sizes as shown in Fig. 5. That is, when the reflective layer 12 is viewed in a plan view, for example, it is preferable that the total area of ​​the first inclined surface 122 is larger than the total area of ​​the second inclined surface 123. In this case, by installing the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment so that the first inclined surface 122 faces a main light source (such as the sun, indoor lighting installed on the ceiling, or an auxiliary light source), it is possible to more effectively reflect light from the light source to the viewer.

[0059] As described above, when the total area of ​​the first inclined surfaces 122 is larger than the total area of ​​the second inclined surfaces 123, when at least one cross section cut in the thickness direction of the reflective layer 12 (particularly, a cross section cut parallel to the direction in which the first inclined surfaces 122 and the second inclined surfaces 123 are arranged), the angle of the normal to the first inclined surfaces 122 (in FIG. 5, “θ s ") is preferably -40° or more, more preferably -35° or more, and even more preferably -30° or more, based on the normal to one surface of the reflective layer 12 (normal to the incident surface). The above angle is preferably -1° or less, more preferably -3° or less, and even more preferably -5° or less. When the angle of the first inclined surface 122 is in the above range, it is possible to more effectively reflect light to the viewer.

[0060] The method of producing the reflective layer 12 having the sawtooth structure 121 is not particularly limited, and for example, the reflective layer 12 can be produced by forming the support region 125, and then sequentially stacking the sawtooth structure 121 and the transparent region 124 on the support region 125. When forming the support region 125, it is preferable to form the surface on the side where the sawtooth structure 121 is stacked into a shape corresponding to the sawtooth structure 121. The material of the support region 125 is not particularly limited, and resin, metal, etc. can be used. From the viewpoint of ease of forming a shape corresponding to the sawtooth structure 121, resin is preferable, and metal is preferable when the material also serves as an electrode of a display element. The material of the sawtooth structure 121 is not particularly limited as long as it can form a mirror surface with high reflectance, and it is preferable to use a metal such as aluminum, silver, or nickel. In particular, as described above, it is preferable to form the sawtooth structure 121 by evaporating a metal onto the surface of the support region 125 formed with a shape corresponding to the sawtooth structure 121. The material of the transparent region 124 is not particularly limited as long as it has a high light transmittance, and for example, resin, glass, etc. can be used.

[0061] Although the sawtooth structure 121 has been described in detail above as an example of the uneven structure in this embodiment, the uneven structure is not limited to the sawtooth structure 121 and may be another structure, for example, a structure formed randomly. In addition, the uneven structure is not limited to one composed of only flat surfaces, but may be one composed of only curved surfaces, or one composed of a combination of flat surfaces and curved surfaces.

[0062] The thickness of the reflective layer 12 in this embodiment is not particularly limited, but may be, for example, 0.1 μm or more, particularly 1 μm or more, and may be 1000 μm or less, particularly 500 μm or less.

[0063] 4.Display layer The display layer 13 in this embodiment is not particularly limited as long as it can display the display content and has light transmittance. For example, the display layer 13 may be a printed layer in which the display content is printed on an adjacent layer, a transparent or semi-transparent film on which characters or images are printed, or a display device that displays electronically. Examples of such display devices include liquid crystal displays, electronic paper, electrophoretic displays, MEMS displays, and solid crystal displays.

[0064] 5.Auxiliary light source The auxiliary light source 14 in the present embodiment is not particularly limited as long as it can irradiate light onto the display layer 13 and does not significantly impede visibility of the display content. A preferred example of the auxiliary light source 14 is a front light including a light source and a light guide member.

[0065] The light guide member in the front light is preferably provided so as to cover the layers (light diffusion control layer 11, display layer 13, etc.) located directly below the auxiliary light source 14. In addition, the light source is preferably provided on at least a part of the periphery of the auxiliary light source 14 and in contact with the light guide member.

[0066] The light guide member guides light rays emitted from a light source to the display layer 13. The configuration of the light guide member is not limited as long as it exerts such an action, and may be, for example, one having projections and recesses forming a prism inside, or one coated with a reflective material containing particles that reflect light.

[0067] The position of the light source is not limited as long as it can irradiate light onto the display layer 13 via the light guide member, and may be provided, for example, at an upper position on the periphery of the display surface (upper side from the viewer's perspective).

[0068] The auxiliary light source 14 preferably irradiates light rays to the light diffusion control layer 11 under the following conditions. That is, 60% of the light rays irradiated from the auxiliary light source 14 immediately after entering the light diffusion control layer 11 preferably have an incidence angle in the range of -45° or more, and particularly preferably have an incidence angle in the range of -41° or more. Also, 60% of the light rays irradiated from the auxiliary light source 14 immediately after entering the light diffusion control layer 11 preferably have an incidence angle in the range of -20° or less, more preferably have an incidence angle in the range of -25° or less, particularly preferably have an incidence angle in the range of -30° or less, and further preferably have an incidence angle in the range of -35° or less.

[0069] 6.Other components The ambient light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment may include components other than the light diffusion control layer 11, the reflective layer 12, the display layer 13, and the auxiliary light source 14 described above.

[0070] For example, the external light-utilizing display bodies 1a, 1b, 2a, and 2b may have a surface coating layer, a cover panel, or the like, provided on the outermost surface facing the viewer, and a backlight, or the like, may be provided on the outermost surface facing away from the viewer.

[0071] Furthermore, the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment may include a deflection element that deflects the optical path of the light beam. Even when such a deflection element is included, the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment can achieve excellent visibility by satisfying the conditions according to the above-mentioned formula (1) or (2).

[0072] Although the shape of the display surface of the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to this embodiment is not particularly limited, it is typically preferable that the display surface has a rectangular shape. In this case, the display surface may be a rectangle consisting of a pair of long sides and a pair of short sides, or a square with all sides of equal length. In addition, the shape of the display surface may be a quadrangle other than a rectangle, such as a rhombus, trapezoid, or parallelogram, a polygon other than a quadrangle, such as a triangle or pentagon, a circle such as a regular circle or an ellipse, or an indefinite shape other than these.

[0073] 7. Manufacturing method of an external light-utilizing display The manufacturing method of the external light-utilizing display bodies 1a, 1b, 2a, and 2b according to the present embodiment is not particularly limited, and they can be manufactured by a conventional manufacturing method. For example, the external light-utilizing display bodies 1a, 1b, 2a, and 2b can be obtained by manufacturing the light diffusion control layer 11, the reflective layer 12, the display layer 13, and, if necessary, the auxiliary light source 14, respectively, and then stacking them in a predetermined stacking order. EXAMPLES

[0074] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0075] [Preparation of Reflective Layer] A reflective layer having a sawtooth structure in which first inclined surfaces and second inclined surfaces are alternately arranged was prepared. As shown in Fig. 5, the reflective layer has the sawtooth structure 121, a support region 125 that supports the sawtooth structure 121, and a transparent region 124 laminated on the sawtooth structure 121. When the reflective layer 12 is viewed in plan, the total area of ​​the first inclined surfaces 122 of the reflective layer is larger than the total area of ​​the second inclined surfaces 123.

[0076] With respect to the dimensions of the above-mentioned reflective layer, the angle of the normal to the first inclined surface 122 (in FIG. 5, “θ s5) is 100 μm, and the thickness of support region 125 (length indicated by "T" in FIG. 5) is 150 μm.

[0077] Regarding the material of the reflective layer, the transparent region 124 is made of a transparent resin material with a refractive index of 1.4. The sawtooth structure 121 is formed by evaporating aluminum onto the surface of the support region 125, and the entire surface is a mirror surface.

[0078] [Preparation of light diffusion control layer] As the light diffusion control layer, films A to C having a regular internal structure with a plurality of regions with a relatively high refractive index in a region with a relatively low refractive index and exhibiting predetermined light diffusion characteristics were prepared. These films were produced by the method disclosed in JP 2021-032961 A and the like.

[0079] The films A to C each have the angular haze value (%) shown in FIG. 6. The films A to C each have the angular haze value (%) shown in Table 1 below. dd- and θ dd+ Shows.

[0080] [Table 1]

[0081] Example 1 The film A prepared as described above was laminated on the surface of the transparent region side of the reflective layer prepared as described above to obtain an external light-utilizing display sample A. At this time, the light ray traveling surface of the light diffusion control layer (the surface including the normal to one side of the light diffusion control layer and the diffusion central axis of the light diffusion control layer) was laminated parallel to the arrangement direction of the teeth of the sawtooth structure in the reflective layer. Although the sample A does not have a display layer, the optical characteristics such as the optical path of the incident light ray are almost the same as when a display layer is provided.

[0082] For the external light display sample A, θ id When θ is -25° od The result is about -6°. Therefore, in the case of the ambient light display sample A, θ id (-25°)<θ dd- (-17.9°)≦θ od (-6°)≦θ dd+ (3.5°) This relation holds true, that is, it satisfies the above-mentioned formula (1).

[0083] This relational expression is satisfied in all cases where the light beam irradiation position is scanned along the intersection line between the incident surface and the light ray traveling plane (the plane containing the normal to the incident surface and the diffusion central axis of the light diffusion control layer), so the proportion of light beams that satisfy expression (1) is 100%.

[0084] Example 2 An external light-utilizing display sample B was obtained in the same manner as in Example 1, except that film B was used instead of film A. id When θ is -25° od Therefore, in the case of the ambient light display sample B, θ dd- (-38.8 or less) ≤ θ id (-25°)≦θ dd+ (-22.1°)<θ od (-9.5°) This relation holds true, that is, it satisfies the above-mentioned formula (2).

[0085] This relational expression is satisfied in all cases where the light beam irradiation position is scanned along the intersection line between the incident surface and the light ray traveling plane (the plane containing the normal to the incident surface and the diffusion central axis of the light diffusion control layer), so the proportion of light beams that satisfy expression (2) is 100%.

[0086] Comparative Example 1 An external light-utilizing display sample C was obtained in the same manner as in Example 1, except that film C was used instead of film A. id When θ is -25° od The calculated value is -20.7°. As shown in Table 1 above, the θ dd- =-31.6° or less, θ dd+ =-9.3°, and within these ranges, θ id and θ od Therefore, the above-mentioned formula (1) and formula (2) are not satisfied, and the proportion of light rays that satisfy these formulas is never 50% or more.

[0087] [Test Example] (Measurement of diffuse light reflectance) The ambient light-utilizing display samples obtained in the examples and comparative examples were measured for diffuse light reflectance using a diffuse luminance distribution measuring device (manufactured by Suga Test Instruments Co., Ltd., product name "Variable Goniometer VC-2").

[0088] Specifically, the surface of the light diffusion control layer side of the external light utilization type display sample is id A light beam was irradiated at an incidence angle of -25°, and the light intensity of the diffused light reflected by the ambient light display sample was measured while changing the angle of the receiver. The angle of the receiver was set so that the angle (receiver angle) between the line segment connecting the emission point (the point where the reflected light is generated by the light beam) and the receiver and the normal line passing through the emission point on the sample surface was -20° to 45°. The angle value is expressed as a negative value when the receiver is inclined toward the first inclined surface of the reflective layer (facing the first inclined surface), and as a positive value when the receiver is inclined toward the second inclined surface (facing the second inclined surface). The light source used was a C light source.

[0089] On the other hand, as a reference, a standard white component board was placed as the measurement target, and the reference value of the light intensity was measured with the receiver angle fixed at -45°. Then, the ratio of the light intensity of each ambient light-utilizing display sample measured as described above to the reference value (percentage with the reference value set at 100%) was calculated. The results are shown in Figure 7. In Figure 7, the horizontal axis represents the receiver angle (converted into the angle in the light diffusion control layer) and the vertical axis represents the light intensity (%).

[0090] 7, the ambient light-utilizing display samples according to Examples 1 and 2 achieved a higher diffuse light reflectance in a wider angle range than the ambient light-utilizing display sample according to Comparative Example 1. In other words, the ambient light-utilizing display samples according to Examples 1 and 2 exhibited excellent visibility. [Industrial Applicability]

[0091] The external light-utilizing display of the present invention can be used as a display that utilizes external light, and can be particularly suitably used as a smart watch, tablet, electronic paper, signboard, advertisement, road sign, etc. [Explanation of symbols]

[0092] 1a, 1b, 2a, 2b...Display using external light 11...Light diffusion control layer 12...Reflection layer 121…Sawtooth structure 122...First inclined surface 123...Second inclined surface 124...Transparent area 125…Support area 13…display layer 14…Auxiliary light source

Claims

1. An external light utilizing display body comprising a light diffusion control layer, a display layer, and a reflective layer, which are laminated in the order of the light diffusion control layer, the display layer, and the reflective layer, or the display layer, the light diffusion control layer, and the reflective layer, the light diffusion control layer has a regular internal structure including a plurality of regions having a relatively high refractive index within a region having a relatively low refractive index; the reflective layer has an uneven structure when viewed in at least one cross section cut in a thickness direction, and a surface of the uneven structure constitutes a reflective surface; The surface located farther from the reflective layer in the external light-utilizing display is defined as the incident surface, and the surface including the normal to the incident surface and the central diffusion axis of the light diffusion control layer is defined as the light ray traveling surface. When expressing the angle between the light ray traveling on the light ray traveling surface and the normal to the incident surface, a negative sign is used when the light ray enters from the main inclination direction side of the uneven structure or exits toward the main inclination direction side, based on the normal to the incident surface, and a positive sign is used in the opposite case. The main inclination direction of the unevenness structure means a more frequent inclination direction when, for a cross section of the unevenness structure obtained by cutting the cross section at the light ray traveling plane, the position in the thickness direction of the reflective layer in the unevenness structure is differentiated with respect to the position in the in-plane direction of the reflective layer, and the inclination directions of the minute surfaces in the unevenness structure are classified according to whether the differential value is a positive value or a negative value. When a light ray traveling along the light ray traveling surface and having a predetermined incident angle is irradiated onto the incident surface while scanning along the intersection line between the light ray traveling surface and the incident surface, the proportion of the light rays that satisfy the condition of the following formula (2) is 50% or more. i ｄｄ－ ≦θ ｉｄ ≦θ ｄｄ＋ <θ ｏｄ …(2) (The above θ ｉｄ means an angle of the light ray traveling from the incident surface toward the reflective layer with respect to the normal line of the incident surface immediately after the light ray enters the light diffusion control layer, and is −35° or −25°. (The above θ ｏｄ means an angle of a light ray having the highest light intensity among the light rays traveling from the light diffusion control layer to the reflective layer, which is reflected by the reflective layer and travels toward the incident surface, with respect to the normal to the incident surface immediately after the light ray enters the light diffusion control layer.) (The above θ ｄｄ－ and θ ｄｄ＋ are the lower limit and upper limit angles of the diffusion angle range of the light diffusion control layer, respectively, converted into angles in the light diffusion control layer, taking into consideration refraction occurring at the interface between air and the light diffusion control layer, and the diffusion angle range is the range of incident angles in which, when light is sequentially incident on one surface of the light diffusion control layer alone at angles of incidence in the range of -90° to 90° and the haze value of the transmitted light emerging from the other surface is measured, the haze value is 90% or more.

1. A display device that utilizes external light.

2. An external light utilizing display body comprising an auxiliary light source, a light diffusion control layer, a display layer, and a reflective layer, which are laminated in the order of the auxiliary light source, the light diffusion control layer, the display layer, and the reflective layer, or the auxiliary light source, the display layer, the light diffusion control layer, and the reflective layer, the auxiliary light source irradiates light onto the display layer, the light diffusion control layer has a regular internal structure including a plurality of regions having a relatively high refractive index within a region having a relatively low refractive index; the reflective layer has an uneven structure when viewed in at least one cross section cut in a thickness direction, and a surface of the uneven structure constitutes a reflective surface; The surface located farther from the reflective layer in the external light-utilizing display is defined as the incident surface, and the surface including the normal to the incident surface and the central diffusion axis of the light diffusion control layer is defined as the light ray traveling surface. When expressing the angle between the light ray traveling on the light ray traveling surface and the normal to the incident surface, a negative sign is used when the light ray enters from the main inclination direction side of the uneven structure or exits toward the main inclination direction side, based on the normal to the incident surface, and a positive sign is used in the opposite case. The main inclination direction of the unevenness structure means a more frequent inclination direction when, for a cross section of the unevenness structure obtained by cutting the cross section at the light ray traveling plane, the position in the thickness direction of the reflective layer in the unevenness structure is differentiated with respect to the position in the in-plane direction of the reflective layer, and the inclination directions of the minute surfaces in the unevenness structure are classified according to whether the differential value is a positive value or a negative value. When the light beam originating from the auxiliary light source traveling along the light beam traveling plane is irradiated onto the incident surface, the ratio of the light beams that satisfy the condition of the following formula (2) is 50% or more: i ｄｄ－ ≦θ ｉｄ ≦θ ｄｄ＋ <θ ｏｄ …(2) (The above θ ｉｄ means an angle of a light ray originating from the auxiliary light source traveling from the incident surface toward the reflective layer, with respect to a normal line of the incident surface immediately after the light ray enters the light diffusion control layer.) (The above θ ｏｄ means an angle, based on the normal to the incident surface, of the light rays with the highest light intensity among the light rays originating from the auxiliary light source traveling from the light diffusion control layer to the reflective layer, which are reflected by the reflective layer and travel toward the incident surface immediately after entering the light diffusion control layer.) (The above θ ｄｄ－ and θ ｄｄ＋ are the angles obtained by converting the lower limit and upper limit of the diffusion angle range of the light diffusion control layer into angles in the light diffusion control layer, taking into consideration refraction occurring at the interface between air and the light diffusion control layer, and the diffusion angle range is the range of incidence angles in which, when light is sequentially incident on one surface of the light diffusion control layer alone at incidence angles in the range of -90° to 90° and the haze value of the transmitted light emerging from the other surface is measured, the haze value is 90% or more.

1. A display device that utilizes external light.

3. The external light-utilizing display body as described in claim 1 or 2, characterized in that the uneven structure, when viewed in at least one cross section cut in the thickness direction, is a sawtooth structure in which first inclined surfaces having a predetermined inclination and second inclined surfaces having an inclination different from that of the first inclined surfaces are arranged alternately.

4. When the reflective layer is viewed in plan, a total area of ​​the first inclined surfaces is larger than a total area of ​​the second inclined surfaces, When at least one cross section obtained by cutting the reflective layer in a thickness direction is viewed, an angle of a normal line of the first inclined surface is −40° or more and −1° or less with respect to a normal line of the incident surface.

4. The external light-utilizing display according to claim 3.

5. The external light-utilizing display satisfies the formula (2), Said θ ｄｄ－ is equal to or greater than -38° and less than -13°, Said θ ｄｄ＋ is greater than or equal to -13° and less than or equal to 19° 5. The display device according to claim 1, wherein the display device is a display that utilizes external light.

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