Light emitting device, lighting system, and optical communication system

Abstract

A light emitting device (1) includes a light guide (10) having a light-transmissive member (11) and a light control layer (12), the light-transmissive member having light-transmissivity at least in a visible light region, the light control layer being provided on at least a part of a surface of the light-transmissive member (11), and a light source (20) that emits light toward at least one end surface of the light-transmissive member (11), the light control layer (12) having a reflection wavelength selectivity in which a wavelength of reflected light depends on an incident angle of incident light.

Description

Technical Field

[0001] This invention relates to light-emitting devices, lighting systems, and optical communication systems. Background Technology

[0002] As a light-emitting device, there are known lighting devices that emit illumination light. In a lighting device, light emitted from a light source is extracted to the outside as illumination light using optical components such as light guide plates, lenses, or filters, depending on the purpose or function.

[0003] For example, Patent Document 1 discloses a lighting device that, for the purpose of achieving high decorative effect, allows a portion of white light emitted from a white light source to pass through a blue filter, so that both white and blue light are incident into a light guide section. The ratio of white light to blue light is changed according to the incident position of the light guide section, thereby illuminating light whose hue changes gradually from blue to orange.

[0004] (Existing technical literature)

[0005] (Patent Documents)

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-141840 Summary of the Invention

[0007] The purpose of this invention is to provide a light-emitting device, etc., which can extract light by adjusting the positional relationship of multiple optical components and a light source, thereby enabling a new extraction method.

[0008] One embodiment of the light-emitting device according to the present invention is as follows: the light-emitting device comprises: a light guide having a light-transmitting component and a light control layer, the light-transmitting component being light-transmitting at least in the visible light region, the light control layer being disposed on at least a portion of the surface of the light-transmitting component; and a light source emitting light toward at least one end face of the light-transmitting component, the light control layer having a reflection wavelength selectivity, the reflection wavelength selectivity being that the wavelength of the reflected light depends on the incident angle of the incident light.

[0009] One aspect of the lighting system proposed in this invention includes the aforementioned light-emitting device as a lighting apparatus.

[0010] The present invention relates to one embodiment of an optical communication system, which includes the aforementioned light-emitting device as an optical transmission device.

[0011] This invention enables the extraction of light using a novel extraction method. Attached Figure Description

[0012] Figure 1 This is a perspective view of the light-emitting device in Embodiment 1.

[0013] Figure 2This is a cross-sectional view of the light-emitting device in Embodiment 1.

[0014] Figure 3A This is a graph showing the reflection spectrum of a colloidal crystal film G that appears green when viewed from above.

[0015] Figure 3B This is a graph showing the reflection spectrum of a colloidal crystal film R that appears red when viewed from above.

[0016] Figure 4 This is a diagram used to illustrate the optical function of the light-emitting device in Comparative Example 1.

[0017] Figure 5 This is a diagram used to illustrate the optical function of the light-emitting device in Comparative Example 2.

[0018] Figure 6 This is a diagram used to illustrate the optical function of the light-emitting device in the embodiment.

[0019] Figure 7 This is a cross-sectional view showing the performance of light emitted by the light-emitting device in an embodiment where a colloidal crystal film R is used as the light control layer.

[0020] Figure 8 This is a perspective view showing the behavior of light emitted by a light-emitting device in an embodiment where a colloidal crystal film R is used as a light control layer.

[0021] Figure 9 This is a cross-sectional view showing the performance of light emitted by the light-emitting device in an embodiment where a colloidal crystal film G is used as the light control layer.

[0022] Figure 10 This is a diagram illustrating the outline of an experiment used to measure the emission spectrum of a light-emitting device.

[0023] Figure 11 This is a graph showing the emission spectrum of the light source used in the experiment when measuring the emission spectrum of the light-emitting device.

[0024] Figure 12 This is a graph showing the emission spectrum of the light-emitting device of Comparative Example 1.

[0025] Figure 13 This is a graph showing the chromaticity of the emission spectrum of the light-emitting device of Comparative Example 1.

[0026] Figure 14 This is a graph showing the emission spectrum of the light-emitting device of Example 1.

[0027] Figure 15 This is a graph showing the chromaticity of the emission spectrum of the light-emitting device of Embodiment 1.

[0028] Figure 16 This is a graph showing the emission spectrum of the light-emitting device of Example 2.

[0029] Figure 17 This is a graph showing the chromaticity of the emission spectrum of the light-emitting device of Embodiment 2.

[0030] Figure 18 This is a graph showing the angular dependence of the luminous intensity of light extracted from the light control layer in the light-emitting devices of Examples 1 and 2.

[0031] Figure 19 This is a perspective view of the light-emitting device in a variation of Embodiment 1.

[0032] Figure 20 This is a cross-sectional view of the light-emitting device in Embodiment 2.

[0033] Figure 21 This is a perspective view of the light-emitting device viewed from the rear side in a variation of Embodiment 2.

[0034] Figure 22 This is a cross-sectional view of the light-emitting device in Variation Example 1.

[0035] Figure 23 This is a perspective view of the light-emitting device in variation example 2.

[0036] Figure 24 This is a cross-sectional view of the light-emitting device in variation example 2.

[0037] Figure 25 This is a perspective view of the light-emitting device in variation example 3.

[0038] Figure 26 This is a cross-sectional view of the light-emitting device in variation example 4.

[0039] Figure 27 This is a perspective view of the light-emitting device in variation example 5.

[0040] Figure 28 This is a cross-sectional view of the light-emitting device in variation example 6.

[0041] Figure 29 This is a cross-sectional view of the light-emitting device in variation example 7.

[0042] Figure 30 This is a cross-sectional view of the light-emitting device in variation example 8.

[0043] Figure 31 This is a cross-sectional view of the light-emitting device in variation example 9.

[0044] Figure 32 This is a cross-sectional view of the light-emitting device in Variation Example 10.

[0045] Figure 33This is a cross-sectional view of the light-emitting device in Variation Example 11.

[0046] Figure 34 This is a cross-sectional view of the light-emitting device in variation 12.

[0047] Figure 35 This is a cross-sectional view of the light-emitting device in variation 13. Detailed Implementation

[0048] The following detailed description of embodiments of the present invention is provided with reference to the accompanying drawings. Furthermore, the embodiments described below are merely specific examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement positions of constituent elements, and connection methods shown in the following embodiments are all examples and are not intended to limit the present invention. Additionally, constituent elements not described in the independent technical solutions in the following embodiments are described as arbitrary constituent elements.

[0049] Furthermore, the figures are schematic diagrams, not rigorous illustrations. Additionally, the same symbols are sometimes used for substantially identical components in the figures, and repetitive explanations are omitted or simplified.

[0050] (Implementation Method 1)

[0051] Firstly, regarding the structure of the light-emitting device 1 in Embodiment 1, using... Figure 1 as well as Figure 2 Please provide an explanation. Figure 1 This is a perspective view of the light-emitting device 1 in Embodiment 1. Figure 2 This is a cross-sectional view of the same light-emitting device 1.

[0052] like Figure 1 as well as Figure 2 As shown, the light-emitting device 1 includes a light guide 10 for guiding light, a light source 20 for emitting light, and a frame 30 for housing the light source 20.

[0053] The light guide 10 is an optical component that guides light emitted from the light source 20 and directs it to the outside of the light guide 10. In this embodiment, the light guide 10 has a light-transmitting component 11 and a light control layer 12. Light emitted from the light source 20 is incident on the light-transmitting component 11, and the light control layer 12 imparts optical effects to the light from the light source 20 incident on the light guide 10 and emits it to the outside of the light guide 10.

[0054] The light-transmitting component 11 is an optical component that is light-transmitting at least in the visible light region. In other words, the light-transmitting component 11 has the optical property of allowing visible light to pass through. The higher the transmittance of the light-transmitting component 11, the better; at least 50% or more is acceptable. Specifically, the light-transmitting component 11 can be transparent to visible light. The transparent light-transmitting component 11 has a high transmittance to the extent that the opposite side can be seen through it. In this case, the transmittance of the transparent light-transmitting component 11 to visible light is 70% or more, preferably 80% or more, and more preferably 90% or more. Furthermore, the light-transmitting component 11 can be light-transmitting not only in the visible light region but also in the near-infrared region. In other words, the light-transmitting component 11 can be light-transmitting in both the visible light region and the near-infrared region.

[0055] The light-transmitting member 11 has a first end face 11a and a second end face 11d located on the opposite side of the first end face 11a. In this embodiment, the light-transmitting member 11 is a flat substrate, further having a first main surface 11b and a second main surface 11c facing away from the first main surface 11b. The first main surface 11b and the second main surface 11c are the surfaces visible when the substrate, i.e., the light-transmitting member 11, is viewed from above. In this case, the first end face 11a and the second end face 11d become the side surfaces of the substrate. In this embodiment, the light-transmitting member 11 is a substrate with a rectangular shape when viewed from above. In this case, the first end face 11a is parallel to the second end face 11d, and the first main surface 11b is parallel to the second main surface 11c. Furthermore, the first end face 11a and the second end face 11d are perpendicular to the first main surface 11b and the second main surface 11c. In addition, the thickness of the light-transmitting component 11 is, for example, a few millimeters to a few centimeters, but it is not limited to this.

[0056] The light-transmitting component 11 is made of a light-transmitting material. The light-transmitting component 11 can be, for example, a transparent resin substrate made of a transparent resin material or a glass substrate made of a transparent glass material, which is a transparent substrate that is transparent to visible light. As the transparent resin substrate, an acrylic substrate made of acrylic resin or a polycarbonate substrate made of polycarbonate resin can be used. Alternatively, the transparent resin substrate can be a rigid substrate without flexibility or a flexible substrate. In this embodiment, a rigid and transparent acrylic substrate is used as the light-transmitting component 11.

[0057] Furthermore, the light-transmitting component 11 functions as a light guide plate. In other words, light incident on the light-transmitting component 11 is guided and propagated inside the light-transmitting component 11, and then emitted outward from the light-transmitting component 11. Therefore, the light-transmitting component 11 has a light-incident surface where light is incident and a light-exit surface where light incident on the light-incident surface is emitted outward. In this embodiment, the first end face 11a of the light-transmitting component 11 becomes the light-incident surface where light emitted from the light source 20 is incident, and the surfaces other than the first end face 11a of the light-transmitting component 11 become the light-exit surfaces where light guided inside the light-transmitting component 11 is emitted outward from the light-transmitting component 11. For example, in the light-transmitting component 11, the first main surface 11b, the second main surface 11c, and the second end face 11d become the light-exit surfaces. As a variation, which will be described later, the first main surface 11b, the second main surface 11c, and the second end surface 11d can also be made into light incident surfaces, and surfaces other than the first main surface 11b, the second main surface 11c, and the second end surface 11d can also be made into light exiting surfaces.

[0058] The light control layer 12 is an optical component that imparts optical effects to light incident on it. The light control layer 12 is disposed on at least a portion of the surface of the light-transmitting component 11. Therefore, the light control layer 12 imparts optical effects to light incident from the light-transmitting component 11 onto the light control layer 12. The optical effects of the light control layer 12 will be described later.

[0059] In this embodiment, a light control layer 12 is disposed on the first main surface 11b of the light-transmitting member 11. Specifically, the light control layer 12 is formed on the entire surface of the first main surface 11b in a manner that is in contact with the first main surface 11b of the light-transmitting member 11. The thickness of the light control layer 12 is uniform throughout the entire light control layer 12. In other words, the thickness of the light control layer 12 remains constant. The thickness of the light control layer 12 is preferably 5 μm or more and 100 μm or less, but is not limited thereto.

[0060] The light control layer 12 has a reflection wavelength selectivity, which means that the wavelength of the reflected light depends on the incident angle of the incident light. In other words, the light control layer 12 has a reflection wavelength selectivity in which the wavelength of the reflected light when the incident light is reflected by the light control layer 12 depends on the incident angle of the incident light.

[0061] Specifically, the light control layer 12 has a three-dimensional periodic structure, i.e., a three-dimensional periodic structure. In this embodiment, the light control layer 12 is a colloidal crystal film containing colloidal crystals. The light control layer 12, as a colloidal crystal film, is as follows: Figure 2As shown in the enlarged view, the light control layer 12 is composed of multiple nanoparticles 12a and a parent resin 12b holding the nanoparticles 12a. In this embodiment, the multiple nanoparticles 12a (colloidal particles) are arranged in a three-dimensional periodic and orderly manner, existing as colloidal crystals within the parent resin 12b. Specifically, the multiple nanoparticles 12a are colloidal crystals arranged periodically and orderly in the thickness direction of the light-transmitting component 11 and in a three-axis direction (horizontal direction) parallel to the first main surface 11b of the light-transmitting component 11. The multiple nanoparticles 12a are uniformly arranged throughout the light control layer 12.

[0062] Nanoparticles 12a are particles with a particle size in the nanometer range. In this embodiment, the particle size of the nanoparticles 12a contained in the light control layer 12 is substantially uniform, but some degree of deviation is acceptable. Details will be described later. By adjusting the average particle size and / or concentration of the plurality of nanoparticles 12a contained in the light control layer 12, the optical effect of the light control layer 12 can be altered.

[0063] The multiple nanoparticles 12a are, for example, light-transmitting particles. As light-transmitting particles, i.e., nanoparticles 12a, inorganic particles such as silica particles made from SiO2 can be used, or polymer particles such as polystyrene particles or acrylic particles can be used. In this embodiment, silica particles are used as nanoparticles 12a.

[0064] The matrix resin 12b is an adhesive used to fix multiple nanoparticles 12a. The matrix resin 12b is composed of a light-transmitting resin material. In this embodiment, the matrix resin 12b is composed of a resin material that is transparent to visible light. The matrix resin 12b may contain at least one selected from the group consisting of, for example, acrylic resins, polycarbonate resins, cycloolefin resins, epoxy resins, silicone resins, and styrene resins.

[0065] The light control layer 12, which serves as a colloidal crystal film, can be fabricated, for example, in the following manner.

[0066] First, silica particles are added to a monomer made of triethylene glycol dimethacrylate (e.g., "NK ester 3G" manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) at a content of 40%. Then, ultrasonic dispersion is performed to disperse the silica particles in a three-dimensional and ordered arrangement within the monomer. This yields a dispersion in which silica particles are uniformly dispersed as colloidal particles within the monomer. Next, a photopolymerization initiator (e.g., IRGACURE-1173 manufactured by IGM Resins BV) at a weight relative to the monomer is added to this dispersion. The dispersion is then coated onto a light-transmitting component 11 (e.g., an acrylic substrate 200 mm square and 10 mm thick) using a bar coater to form a coated film. A #10 bar coater was used for this process. The resulting coated film is then irradiated with ultraviolet light to polymerize the monomer, thereby creating a colloidal crystal film with colloidal crystals forming a light control layer 12 on the surface of the light-transmitting component 11.

[0067] The colloidal crystal film produced in this way will have different colors when viewed from above, depending on the particle size of the multiple nanoparticles 12a constituting the colloidal crystal. For example, if silica particles with an average particle size of 180 nm are used as nanoparticles 12a, the colloidal crystal film G produced by the above method will appear green when viewed from above. Furthermore, if silica particles with an average particle size of 200 nm are used as nanoparticles 12a, the colloidal crystal film R produced by the above method will appear red when viewed from above.

[0068] The reflectance spectra of the actually fabricated colloidal crystal films G and R were measured. The measurement results are shown in... Figure 3A as well as Figure 3B . Figure 3A This is a graph showing the reflection spectrum of a colloidal crystal film G that appears green when viewed from above. Figure 3B This is a graph showing the reflectance spectrum of a colloidal crystalline film R, which appears red when viewed from above. Additionally, in Figure 3A as well as Figure 3B In the reflected spectra shown, the incident angles were set to 5°, 15°, and 30°, and the reflected spectra were measured for each incident angle. Furthermore, the reflected spectra were measured using a spectrophotometer (V-650) manufactured by Nippon Spectrophotometer Co., Ltd., with measurement option ARMV-734.

[0069] The result, such as Figure 3A as well as Figure 3B As shown, both colloidal crystal films G and R exhibit wavelength selectivity of reflected light, where the wavelength depends on the incident angle of the incident light.

[0070] Specifically, regarding the colloidal crystal film G, such as Figure 3A As shown, with an incident angle of 5°, the peak wavelength of the reflected light is approximately 570 nm; with an incident angle of 15°, the peak wavelength is approximately 560 nm; and with an incident angle of 30°, the peak wavelength is approximately 540 nm. Thus, the colloidal crystal film G has a reflective wavelength region in the green to yellowish-green range. Furthermore, it can be considered that the positive reflection wavelength of the colloidal crystal film G (with an incident angle of 0°) is in the range of 570 nm to 580 nm.

[0071] On the other hand, regarding the colloidal crystal film R, such as Figure 3B As shown, with an incident angle of 5°, the peak wavelength of the reflected light is approximately 645 nm; with an incident angle of 15°, the peak wavelength is approximately 640 nm; and with an incident angle of 30°, the peak wavelength is approximately 610 nm. Thus, the colloidal crystal film R has a reflective wavelength region within the red range. Furthermore, it can be considered that the positive reflection wavelength of the colloidal crystal film R (at an incident angle of 0°) is in the range of 645 nm to 655 nm.

[0072] Light source 20 emits light to light guide body 10. Specifically, light source 20 emits light to at least one end face of light-transmitting component 11 of light guide body 10. In this embodiment, light source 20 emits light towards the first end face 11a of light-transmitting component 11. Therefore, the light emitted by light source 20 is incident on the first end face 11a of light-transmitting component 11. In this embodiment, the optical axis of light source 20 is perpendicular to the first end face 11a of light-transmitting component 11 and parallel to the first main surface 11b of light-transmitting component 11.

[0073] The light source 20 is configured to face the first end face 11a of the light-transmitting member 11. In other words, the light source 20 becomes the edge lamp structure of the light-transmitting member 11. Specifically, the light emitting surface of the light source 20 and the first end face 11a of the light-transmitting member 11 are face to face.

[0074] The light source 20 is an LED module that includes a light-emitting diode (LED). In this embodiment, the light source 20 emits white light. Therefore, the white light emitted from the light source 20 is incident on the light incident surface of the light-transmitting component 11, namely the first end surface 11a.

[0075] The light source 20 includes a light-emitting element 21 and a mounting substrate 22 on which the light-emitting element 21 is mounted. One or more light-emitting elements 21 are mounted on the mounting substrate 22. In this embodiment, multiple light-emitting elements 21 are mounted on the mounting substrate 22. The mounting substrate 22 is an elongated substrate, such as a wiring substrate with metal wiring formed in a predetermined pattern. As the base substrate of the mounting substrate 22, a resin substrate, a ceramic substrate, or an insulatingly coated metal substrate can be used.

[0076] The light-emitting element 21 is an LED light source composed of LEDs. Specifically, the light-emitting element 21 is a white LED light source that emits white light. The light-emitting element 21 is, for example, a surface-mount device (SMD) type LED element, and includes: a white resin or ceramic container (encapsulation body) with a recess, one or more LED chips mounted at the bottom of the recess of the container, and a sealing member that fills and seals the LED chips within the recess of the container. The sealing member is made of a light-transmitting resin material such as silicone resin. The sealing member may also be a phosphor-containing resin containing a wavelength conversion component such as a phosphor.

[0077] An LED chip is an example of a semiconductor light-emitting element that emits light through a specified direct current; it is a bare chip that emits monochromatic visible light. An example of an LED chip is a blue LED chip that emits blue light when powered. In this case, to obtain white light, a yellow phosphor such as YAG (yttrium aluminum garnet) is contained in the sealed component, which uses the blue light from the blue LED chip as excitation light to fluoresce.

[0078] Thus, in this embodiment, the light-emitting element 21 is a white LED element composed of a blue LED chip and a yellow phosphor. Specifically, the yellow phosphor absorbs a portion of the blue light emitted by the blue LED chip and is excited to emit yellow light, which mixes with the blue light not absorbed by the yellow phosphor to become white light. Furthermore, the sealing component is not limited to containing a yellow phosphor; it may also contain a red phosphor and a green phosphor.

[0079] Multiple light-emitting elements 21 are arranged in a linear fashion on the mounting substrate 22 along its length. These linearly arranged light-emitting elements 21 function as a linear light source emitting linear light. In this embodiment, the multiple light-emitting elements 21 are mounted in a row at approximately equal intervals along the length of the mounting substrate 22. Furthermore, each light-emitting element 21 is disposed on the substrate 22 with its main light-emitting surface facing the first end face 11a (light incident surface) of the light-transmitting member 11.

[0080] Alternatively, the light-emitting element 21 can also be an LED element that is itself an LED chip (bare chip). In this case, the light source 20 (LED module) is a COB (Chip On Board) structure where the light-emitting element 21, which is the LED chip, is directly mounted on the mounting substrate 22. When the light source 20 is used as an LED module with a COB structure, for example, if a blue LED chip is used as the light-emitting element 21, multiple blue LED chips are mounted in a row on the mounting substrate 22, and the blue LED chips are sealed individually or together by a sealing component made of silicone resin containing yellow phosphor.

[0081] In addition, as part of or outside the light source 20, optical components such as lenses that change the light distribution of light emitted from the light source 20, filters that control the wavelength of light emitted from the light source 20, or diffusers that scatter and transmit light emitted from the light source 20 may be provided as needed.

[0082] The light source 20 is driven by power supplied by a power supply unit (not shown). The power supply unit may be, for example, a power supply (power circuit) configured on a circuit board with multiple circuit components mounted thereon, and a housing for storing the power supply. The power supply converts the power received by the power supply unit into specified power and supplies power to the light source 20. Thus, the light source 20 is driven to emit light. The power supply unit may be included in the light-emitting device 1, or it may be provided separately from the light-emitting device 1. Furthermore, the light-emitting device 1 may have a built-in power supply.

[0083] The light source 20 is disposed on the frame 30. The frame 30 is, for example, a box-shaped storage component with an opening. The frame 30 is made of, for example, metal or resin. The light source 20 is disposed on the bottom of the frame 30. Specifically, the mounting substrate 22 of the light source 20 is placed on the bottom surface of the frame 30. In addition, the light source 20 and the frame 30 can be integrally formed as a light source unit. Furthermore, in this embodiment, the opening of the frame 30 is blocked by the first end face 11a of the light guide 10, but it is not limited to this.

[0084] In the light-emitting device 1 configured in this way, light emitted from the light source 20 is guided into the light guide 10 from the end face of the light guide 10, and then emitted to the outside from the light guide 10. Specifically, in the light-emitting device 1, light emitted from the light source 20 is guided into the light-transmitting member 11 from the first end face 11a of the light-transmitting member 11, and a portion of the light is transmitted to the light control layer 12 from the first main face 11b. Furthermore, the light transmitted from the light-transmitting member 11 to the light control layer 12 is subjected to optical effects in the light control layer 12 and emitted to the outside from the light control layer 12. Therefore, the outer surface of the light control layer 12 becomes the surface (light emitting surface) from which light is extracted from the light-emitting device 1.

[0085] Furthermore, the light incident on the light-transmitting member 11 includes not only the light emitted to the outside via the light control layer 12, but also light emitted to the outside without passing through the light control layer 12. For example, a portion of the light incident on the light-transmitting member 11 may be emitted from the second main surface 11c and the second end surface 11d of the light-transmitting member 11. Thus, the surface from which light is extracted from the light-emitting device 1 (light emitting surface) includes not only the outer surface of the light control layer 12, but also the second main surface 11c and the second end surface 11d of the light-transmitting member 11.

[0086] The light extracted from the light-emitting device 1 can be used, for example, as illumination light. In this case, the light-emitting device 1 becomes an illumination device that emits illumination light. In particular, in this embodiment, a light guide 10 is used, so the light-emitting device 1 can be used as a light-guiding type illumination device (light-guiding illumination). In addition, the light extracted from the light-emitting device 1 can be used as light other than illumination light.

[0087] Next, we will explain the optical function of the light-emitting device 1 and the light extracted from it. Specifically, using... Figures 4-6 The optical function of the light-emitting device 1 and the light extracted from the light-emitting device 1 will be explained by comparing it with the light-emitting devices of Comparative Examples 1 and 2.

[0088] Figure 4 This is a diagram used to illustrate the optical function of the light-emitting device 1X in Comparative Example 1. Figure 5 This is a diagram used to illustrate the optical function of the light-emitting device 1Y in Comparative Example 2. Figure 6 This is a diagram used to illustrate the optical function of the light-emitting device 1 in this embodiment.

[0089] Figure 4 The light-emitting device 1X shown in Comparative Example 1 is, Figure 6 The light-emitting device 1 shown in this embodiment does not have a structure with a light control layer 12. In other words, the light guide 10X in the light-emitting device 1X of Comparative Example 1 is composed only of a light-transmitting component 11.

[0090] also, Figure 5 The light-emitting device 1Y shown in Comparative Example 2 is that it emits light... Figure 6 The light control layer 12 in the light-emitting device 1 of this embodiment, which is made of a colloidal crystal film, is replaced with a light control layer 12Y made of an optical multilayer film. In other words, the light guide 10Y in the light-emitting device 1Y of Comparative Example 2 is composed of a light-transmitting member 11 and a light control layer 12Y, which is composed of an optical multilayer film formed on the first main surface 11b of the light-transmitting member 11. The optical multilayer film constituting the light control layer 12Y has a structure in which multiple optical films are stacked in the thickness direction of the light-transmitting member 11.

[0091] In addition, Figure 6 The light-emitting device 1 shown in this embodiment includes a light control layer 12. Figure 3B The first light control layer 12R shown is made of a colloidal crystal film R with a reflectance spectrum.

[0092] like Figures 4-6 As shown, in the light-emitting device 1X of Comparative Example 1, the light-emitting device 1Y of Comparative Example 2, and the light-emitting device 1 of this embodiment, the light emitted from the light source 20 enters the light-transmitting member 11 from the first end face 11a of the light-transmitting member 11.

[0093] In this case, such as Figure 4 As shown, in the light-emitting device 1X of Comparative Example 1, a portion of the light guided by the light-transmitting member 11 (i.e., the light guide 10X) is extracted to the outside of the light-transmitting member 11 through the first main surface 11b or the second main surface 11c. On the other hand, another portion of the light guided by the light-transmitting member 11 is guided within the light-transmitting member 11 by repeated total internal reflection at the first main surface 11b and the second main surface 11c, and is not extracted from the first main surface 11b or the second main surface 11c.

[0094] at this time, Figure 4 In the light-emitting device 1X of Comparative Example 1, the color of the light extracted from the first main surface 11b or the second main surface 11c of the light-transmitting member 11 is the same regardless of the angle from which the light emitted from the light source 20 is viewed. For example, when the light emitted from the light source 20 is white light, Figure 4 The color of the light extracted from the first main surface 11b or the second main surface 11c of the light-transmitting component 11 is white light, regardless of the viewing angle.

[0095] In addition, such as Figure 5 As shown, in the light-emitting device 1Y of Comparative Example 2, a portion of the light guided by the light-transmitting member 11 passes through the first main surface 11b and is extracted to the outside of the light guide 10Y via the light control layer 12Y, while the light passes through the second main surface 11c and is extracted to the outside of the light guide 10Y without passing through the light control layer 12Y. On the other hand, the remaining portion of the light guided by the light-transmitting member 11 is guided within the light-transmitting member 11 while undergoing repeated total internal reflection at the first main surface 11b and the second main surface 11c, and is not extracted from either the first main surface 11b or the second main surface 11c.

[0096] At this time, Figure 5In Comparative Example 2, the light-emitting device 1Y has a light control layer 12Y composed of an optical multilayer film with a periodic structure. However, the optical multilayer film constituting the light control layer 12Y is only periodic in the thickness direction of the light-transmitting component 11, in other words, a one-dimensional periodic structure. Therefore, it is conceivable that the light incident from the light-transmitting component 11 into the light control layer 12Y is not subject to diffraction like the light-emitting device 1 of this embodiment described later.

[0097] In addition, such as Figure 6 As shown, in the light-emitting device 1 of this embodiment, a portion of the light guided by the light-transmitting component 11 passes through the first main surface 11b and is extracted to the outside of the light guide 10 via the light control layer 12, and is extracted to the outside of the light guide 10 through the second main surface 11c without passing through the light control layer 12.

[0098] In this situation, Figure 6 The light-emitting device 1 shown has a light control layer 12 composed of a colloidal crystal film R containing a colloidal crystal with a three-dimensional periodic structure. Therefore, light that passes through the first main surface 11b of the light-transmitting component 11 and is extracted to the outside of the light guide 10 via the light control layer 12 is extracted from the light guide 10 when it is incident from the light-transmitting component 11 onto the light control layer 12 by the colloidal crystal film R constituting the light control layer 12 through optical action.

[0099] In this embodiment, the light control layer 12 has a colloidal crystal, which is formed by a plurality of nanoparticles 12a arranged periodically and orderly in the thickness direction of the light-transmitting component 11 and in a three-axis direction (horizontal direction) parallel to the first principal surface 11b of the light-transmitting component 11. Thus, light incident on the light control layer 12 from the first principal surface 11b of the light-transmitting component 11 is diffracted in the light control layer 12 and extracted from the light guide 10 as diffracted light λ.

[0100] At this point, light is incident on the light control layer 12, thereby generating strong diffracted light λ (diffracted wave) in a specific direction according to the periodic intervals of the colloidal crystal. Therefore, in Figure 6 In the light-emitting device 1 shown, the light is guided by the light-transmitting component 11 and incident on the first main surface 11b onto the light control layer 12. The color of the light extracted from the light control layer 12 varies depending on the angle at which the light control layer 12 is viewed.

[0101] Specifically, the light control layer 12 is composed of Figure 3A The colloidal crystal film R shown is composed of a reflectance spectrum, so the light extracted from the light control layer 12, such as Figure 7 as well as Figure 8As shown, light becomes light with a wide range of hues, from red to blue wavelengths, depending on the viewing angle of the light control layer 12. For example, diffracted red light from the light control layer 12 reaches the eye of the user at viewpoint P1, diffracted green light from the light control layer 12 reaches the eye of the user at viewpoint P2, and diffracted blue light from the light control layer 12 reaches the eye of the user at viewpoint P3. In other words, depending on the viewing angle of the light control layer 12, the light control layer 12 is perceived as red, or as green, or as blue.

[0102] On the other hand, in the light incident on the light-transmitting component 11, the light that is guided by the light-transmitting component 11 and passes through the second main surface 11c, and is extracted to the outside of the light guide 10 without passing through the light control layer 12, is not affected by the optical effect of the light control layer 12, and is emitted to the outside from the second main surface 11c of the light-transmitting component 11. Therefore, this light does not diffract in the light control layer 12, so the color of this light does not depend on the viewing angle, but is the same as the color of the light emitted by the light source 20.

[0103] However, the light incident on the light-transmitting component 11 also includes light that is optically affected by the light control layer 12 and exits outward from the second principal surface 11c of the light-transmitting component 11. Specifically, in the light (diffracted light) that is incident on the first principal surface 11b of the light-transmitting component 11 onto the light control layer 12 and diffracted by the light control layer 12, the light that undergoes total internal reflection at the interface between the light control layer 12 and the air layer and returns to the light-transmitting component 11 exits outward from the second principal surface 11c of the light-transmitting component 11.

[0104] In other words, the light extracted from the second main surface 11c of the light-transmitting component 11 includes not only light that is not affected by the optical effects of the light control layer 12, but also light that is affected by the optical effects of the light control layer 12. Therefore, the color of the light extracted from the second main surface 11c of the light-transmitting component 11 varies depending on the angle from which the light-transmitting component 11 is viewed. Specifically, similar to the view of the light control layer 12, the light has a wide range of hues from red wavelength to blue wavelength depending on the angle from which the light-transmitting component 11 is viewed. In other words, depending on the angle from which the second main surface 11c of the light-transmitting component 11 is viewed, the light-transmitting component 11 is perceived as red, or as green, or as blue.

[0105] In addition, Figure 6 The light-emitting device 1 shown has light incident on the light control layer 12 that is diffracted, so as... Figure 5 The light-emitting device 1Y shown is incident from the light-transmitting component 11 at an angle of total internal reflection relative to the light control layer 12, and is diffracted rather than undergoing total internal reflection in the light control layer 12. In other words, as shown... Figure 6As shown, light incident from the light-transmitting component 11 onto the light control layer 12, regardless of the incident angle, almost entirely becomes diffracted light λ, generating very little reflected light λ'. Therefore, Figure 6 The light-emitting device 1 shown is compared to Figure 4 The light-emitting device 1X shown and Figure 5 The light-emitting device 1Y shown can improve light extraction efficiency.

[0106] This serves as the light control layer 12, using a structure with... Figure 3B The first light control layer 12R, formed from a colloidal crystal film R showing the reflected spectrum, is emitted from the light source 20 and guided by the light guide 10. The color of the light extracted from the light guide 10 varies depending on the angle at which it is viewed. Thus, depending on the angle at which the outer surface of the light guide 10 is viewed, the light guide 10 may appear red, green, or blue. In other words, by changing the angle at which the light guide 10 is viewed, the perceived color of the emitted light changes.

[0107] Next, regarding the use of light control layer 12, which has... Figure 3A The case of the second light control layer 12G formed by the colloidal crystal film G showing the reflection spectrum is illustrated. Figure 9 Please provide an explanation.

[0108] Figure 9 The light-emitting device 1 shown is also related to Figure 6 Similarly, in the light-emitting device 1 shown, light from the light source 20 is incident on the end face of the light guide 10 on the first main surface 11b of the light-transmitting member 11, where a light control layer 12 is formed. Therefore, the light incident from the light-transmitting member 11 onto the light control layer 12 is diffracted, becoming diffracted light. Thus, the light extracted from the light guide 10 becomes different colors depending on the viewing angle.

[0109] The light control layer 12, formed of a colloidal crystal film, is capable of extracting light with a shorter wavelength than that of the orthogonal reflection. Therefore, Figure 9 The light-emitting device 1 shown uses a second light control layer 12G, which is a colloidal crystal film G with a positive reflection wavelength in the yellow-green wavelength region, as a light control layer 12. Therefore, it emits light from the light guide 10 as diffracted light with a shorter wavelength than the yellow-green wavelength.

[0110] Specifically, such as Figure 9 When white light from the light source 20 is incident on the end face of the light guide 10, the light extracted from the light guide 10 becomes either diffracted green light or diffracted blue light. In other words, depending on the viewing angle of the light guide 10, the light guide 10 is perceived as green or blue.

[0111] On the other hand, in the light control layer 12 made of colloidal crystal film G, no red diffracted light is generated even when light is incident. Therefore, the red component, i.e., red light, in the white light guided by the light guide 10 is not extracted from the light control layer 12 but is guided within the light-transmitting component 11. The red light guided within the light-transmitting component 11 is emitted to the outside, for example, from the second main surface 11c or the second end surface 11d of the light-transmitting component 11. In other words, when colloidal crystal film G is used instead of colloidal crystal film R as the light control layer 12, the red light is not emitted to the outside from the light control layer 12, but is subjected to the optical action enclosed within the light-transmitting component 11 through the light control layer 12, enabling the red light to be emitted to the outside from other positions of the light guide 10 that are different from the position where the light control layer 12 is provided.

[0112] so Figure 9 The light-emitting device 1 shown is, with Figure 6 The light-emitting device 1 shown is similarly capable of extracting light of different specific wavelengths depending on the viewing angle; however, in Figure 9 The light-emitting device 1 shown can selectively extract a portion of light wavelengths from the light control layer 12, and can confine other wavelengths of light within the light guide 10. Specifically, in Figure 9 The light-emitting device 1 shown can selectively extract light from the light control layer 12 for wavelengths ranging from blue to green, and can enclose light in the light-transmitting member 11 for wavelengths longer than green (the wavelength region of red), and then selectively extract it from the second end face 11d of the light-transmitting member 11.

[0113] pass Figure 6 and Figure 9 It is understood that the wavelength of light extracted from the light control layer 12 can be controlled based on the composition of the colloidal crystals contained in the colloidal crystal film constituting the light control layer 12. Furthermore, a specific wavelength can be confined within the light-transmitting component 11 based on the composition of the colloidal crystals contained in the colloidal crystal film constituting the light control layer 12.

[0114] Therefore, the light-emitting device 1 of this embodiment can be used not only as an illumination device that illuminates different colors of light according to the viewing angle, or as a color-changing light guide device that guides different colors of light according to the viewing angle, but also as a narrow-band wavelength selective filter or a beam splitter. Furthermore, as... Figure 9 Like the light-emitting device 1 shown, it can enclose light of a specific wavelength in the light-transmitting component 11. Therefore, the light-emitting device 1 in this embodiment can be used as an optical transmission device with an optical waveguide that transmits light of a specific wavelength.

[0115] Next, an experiment was conducted to verify the optical function of the light-emitting device 1 in this embodiment. Regarding the results of this experiment, [the following is a summary of the results]. Figures 10-18 Please provide an explanation.

[0116] In this experiment, targeting Figure 2 The light-emitting device 1 and the light-emitting device shown in this embodiment are shown. Figure 4 The light-emitting device 1X of Comparative Example 1 shown above was used to measure the angular dependence of hue and luminous intensity of light extracted from the light control layer. In this case, the light-emitting device 1 in this embodiment uses a light control layer 12 with... Figure 3A The case of the colloidal crystal film G with the reflected spectrum shown is designated as "Example 1". A light control layer 12 using a film with... Figure 3B The case of the colloidal crystal film R with the reflected spectrum shown is designated as "Example 2". In addition, in the light-emitting device 1X of Comparative Example 1, a light guide 10X is used in which only the light-transmitting component 11 is used and no light control layer 12 (colloidal crystal film) is formed in the light-transmitting component 11.

[0117] Figure 10 This is a diagram used to illustrate the general outline of this experiment. For example... Figure 10 As shown, in this experiment, the light-emitting device 1 of this embodiment has an aluminum strip attached to its second end face 11d, thus preventing light from emanating from the second end face 11d. White light is incident from a line light source, i.e., light source 20, onto the end face of the light guide 10, causing the light control layer 12 of the light guide 10 to emit light. The emission spectrum of the light control layer 12 at this time is measured using a spectrophotometer 100 (MCPD-7000 manufactured by Otsuka Electronics Co., Ltd.), and the luminance is calculated based on the emission spectrum. Furthermore, the luminous intensity is calculated. At this time, as... Figure 10 As shown, in a three-dimensional orthogonal coordinate measurement system of the X, Y, and Z axes, with the X-axis direction perpendicular to the outer surface of the light control layer 12 set to 90°, the positive Y-axis direction set to 0°, and the negative Y-axis direction set to 180°, angles of 30°, 45°, 60°, 90°, and 120° are used as measurement directions in the XY plane, and the emission spectrum is measured in each measurement direction. Furthermore, the measurement direction represents the direction in which the user views the light guide 10. In addition, regarding chromaticity, it is represented by chromaticity coordinates in the xy chromaticity diagram of the CIE 1931 color space. Although not shown, the light-emitting device 1X of Comparative Example 1 is also represented by... Figure 10 The emission spectrum of the light-emitting device 1 shown in this embodiment is measured using the same method. In addition, as the light-transmitting component 11, both the light-emitting device 1 in this embodiment and the light-emitting device 1X in Comparative Example 1 use a transparent acrylic substrate with a thickness of 10 mm.

[0118] In addition, the light source 20 used in this experiment employed a material with... Figure 11The emission spectrum of the white light source is shown. Specifically, the light source 20 used in this experiment is an LED module with white LED elements, such as... Figure 11 As shown, the white LED element emits white light and includes a blue light-emitting diode that emits blue light with a peak emission wavelength of approximately 455 nm and a YAG phosphor that emits yellow-green fluorescence with a peak emission wavelength of approximately 545 nm. Additionally, a red phosphor with a peak emission wavelength of approximately 615 nm is also added to the white LED element of the light source 20.

[0119] The results measured under these conditions, for the light-emitting device 1X of Comparative Example 1, are obtained according to the angle in each measurement direction. Figure 12 The emission spectrum shown and Figure 13 The displayed chromaticity. (Through) Figure 12 as well as Figure 13 As shown, the emission spectrum and chromaticity of the light-emitting device 1X in Comparative Example 1 are not angle-dependent.

[0120] Specifically, such as Figure 12 As shown in the emission spectrum, the emission peak wavelength remains unchanged even when the angle of the measurement direction changes, and is the same as the emission peak wavelength of the light source 20. Furthermore, as... Figure 13 As shown in the chromaticity diagram, the individual chromaticities at each angle of each measurement direction are almost unchanged compared to the chromaticity of light source 20, and even if the angle of the measurement direction changes, there is almost no change.

[0121] Therefore, in Comparative Example 1, the light-emitting device 1X can display approximately the same white light color from any direction when viewed through the light guide 10X. In other words, white light is extracted from the light guide 10X in an angle-independent manner.

[0122] Furthermore, for the light-emitting device 1 of Embodiment 1, which uses a colloidal crystal film G as the light control layer 12, the angles in each measurement direction were obtained. Figure 14 The emission spectrum shown and Figure 15 The chromaticity shown. For example... Figure 14 as well as Figure 15 As shown, in the light-emitting device 1 of Embodiment 1, the emission spectrum and chromaticity are angle-dependent.

[0123] Specifically, through Figure 14 The emission spectrum shows that the blue emission peak wavelength remains constant even when the measurement angle changes, but the other peak wavelengths vary with the measurement angle. Furthermore, through... Figure 15As shown in the chromaticity diagram, the chromaticity of each angle in each measurement direction changes along with the angle of the measurement direction. In this case, the chromaticity changes beyond the white area, and according to the change of the angle of the measurement direction, it changes in the following manner: yellow-green area (30°) → white area (45°) → blue-violet area (60°) → white area (90°, 120°).

[0124] Thus, with respect to the light-emitting device 1 of Embodiment 1, different colors of light can be seen depending on the angle at which the light guide 10 is viewed. In other words, different colors of light are extracted from the light guide 10 depending on the angle. Specifically, light can be extracted as a gradient light with continuously changing colors.

[0125] Furthermore, for the light-emitting device 1 of Embodiment 2, which uses a colloidal crystal film R as the light control layer 12, the angles in each measurement direction were obtained. Figure 16 The emission spectrum shown and Figure 17 The chromaticity shown. For example... Figure 16 as well as Figure 17 As shown, the light-emitting device 1 in Embodiment 2 also exhibits angle-dependent emission spectrum and chromaticity, similar to the light-emitting device 1 in Embodiment 1.

[0126] Specifically, through Figure 16 The emission spectrum shows that the blue emission peak wavelength remains constant even when the measurement angle changes, but the other peak wavelengths vary with the measurement angle. Furthermore, through... Figure 17 As can be seen from the chromaticity diagram, the chromaticity of each angle in each measurement direction changes along with the angle of measurement. In this case, the chromaticity changes beyond the white area, changing in the following manner according to the angle of measurement: orange area (30°) → yellow-green area (45°) → blue-green area (60°) → white area (90°) → yellow-green area (120°). In other words, the light becomes more colored the more it is viewed from an inclined direction. Specifically, light can be extracted as a gradual change in color.

[0127] Thus, the light-emitting device 1 of Embodiment 2 is similar to the light-emitting device 1 of Embodiment 1; different colors of light can be seen depending on the angle at which the light guide 10 is viewed. In other words, different colors of light are extracted from the light guide 10 depending on the angle.

[0128] Figure 18 This is a graph showing the angular dependence of the luminous intensity of light extracted from the light control layer 12 in the light-emitting devices of Embodiments 1 and 2. Figure 18Regarding the light-emitting device 1 of Examples 1 and 2 and the light-emitting device 1X of Comparative Example 1, emission spectra of the relative light-emitting intensity (light-emitting intensity ratio) of the light-emitting devices 1 of Examples 1 and 2 relative to the light-emitting device 1X of Comparative Example 1 are shown based on the light-emitting intensity measured by spectrophotometer 100 for various measurement directions of 30°, 45°, 60°, 90°, and 120°. Figure 18 The black squares represent the luminous intensity of the light-emitting device 1 of Example 1 / the luminous intensity of the light-emitting device of Comparative Example 1, and the white circles represent the luminous intensity of the light-emitting device 1 of Example 2 / the luminous intensity of Comparative Example 1.

[0129] pass Figure 18 It is understood that by providing a light control layer 12 made of a colloidal crystal film on the light-transmitting component 11, light of a specific wavelength can be extracted according to the angle of the measurement direction, thereby improving the extraction efficiency of light emitted from the light guide 10. In this case, the wavelength of the extracted light varies depending on the composition of the colloidal crystal film.

[0130] Specifically, with the measurement direction angle at 30°, it is evident that the light-emitting devices 1 of Examples 1 and 2, compared to the light-emitting device 1X of Comparative Example 1, exhibit improved light extraction efficiency across the entire wavelength range in the visible light region. Particularly in the light-emitting device 1 of Example 1, it is observed that light near the peak wavelength of 555 nm is rapidly extracted, resulting in a significant improvement in light extraction efficiency. Furthermore, it is evident that in the light-emitting device 1 of Example 2, light near the peak wavelength of 640 nm is particularly rapidly extracted, leading to a substantial improvement in light extraction efficiency.

[0131] Furthermore, when the measurement direction angle is 45°, it can be seen that the light-emitting device 1 of Examples 1 and 2, compared with the light-emitting device 1X of Comparative Example 1, improves the light extraction efficiency across the entire wavelength range in the visible light region. In particular, in the light-emitting device 1 of Example 1, it can be seen that light near the peak wavelength of 470 nm is rapidly extracted, resulting in a significant improvement in light extraction efficiency. Furthermore, it can be seen that in the light-emitting device 1 of Example 2, light near the peak wavelength of 555 nm is particularly rapidly extracted, resulting in a significant improvement in light extraction efficiency.

[0132] Furthermore, when the measurement direction angle is 60°, it can be seen that the light-emitting device 1 of Examples 1 and 2, compared with the light-emitting device 1X of Comparative Example 1, improves the light extraction efficiency across the entire wavelength range in the visible light region. Especially in the light-emitting device 1 of Example 1, it can be seen that light near the peak wavelength of 460 nm is rapidly extracted, resulting in a significant improvement in light extraction efficiency. Furthermore, it can be seen that in the light-emitting device 1 of Example 2, light near the peak wavelength of 470 nm is particularly rapidly extracted, resulting in a significant improvement in light extraction efficiency.

[0133] Furthermore, when the angle of the measurement direction is 90°, it can be seen that the light-emitting device 1 of Examples 1 and 2 also improves the light extraction efficiency of the entire wavelength region of the visible light region compared with the light-emitting device 1X of Comparative Example 1.

[0134] Furthermore, when the measurement direction angle is 120°, it can be seen that the light-emitting devices 1 of Examples 1 and 2, compared with the light-emitting device 1X of Comparative Example 1, have improved the light extraction efficiency across the entire wavelength region of the visible light region below 600 nm. In particular, in the light-emitting device 1 of Example 1, it can be seen that light in the visible light region below 500 nm is rapidly extracted, resulting in a significant improvement in light extraction efficiency. Furthermore, it can be seen that in the light-emitting device 1 of Example 2, light, especially near the peak wavelength of 540 nm, is rapidly extracted, resulting in a significant improvement in light extraction efficiency.

[0135] As explained above, in this embodiment, the positional relationship between the light-emitting device 1, which has a selective reflection wavelength light control layer 12, the light-transmitting component 11, and the light source 20 is adjusted. Specifically, the light control layer 12 is provided on at least a portion of the surface of the light-transmitting component 11 to form a light guide 10, and the light source 20 is configured to emit light toward the first end face 11a of the light-transmitting component 11.

[0136] With this structure, light emitted from the light source 20 and incident on the interior of the light-transmitting member 11 from the first end face 11a is guided inside the light-transmitting member 11 and incident on the light control layer 12. At this time, the light control layer 12 has wavelength selectivity for reflected light, where the wavelength depends on the incident angle of the light. Therefore, the light incident from the light-transmitting member 11 onto the light control layer 12 is subjected to optical effects based on the wavelength selectivity of the light control layer 12 and exits from the light guide 10. Thus, the light exiting the light guide 10 becomes a different color depending on the viewing angle. In other words, the emitted color of the light guide 10 changes according to the viewing angle. Thus, with the light-emitting device 1 in this embodiment, the color of the light guide 10 changes according to the viewing angle, enabling the extraction of light using a new extraction method, namely, extracting light of different specific wavelengths according to the viewing angle. For example, light can be extracted as a gradient light whose color changes continuously by changing the viewing angle.

[0137] In particular, in the light-emitting device 1 of this embodiment, the light control layer 12 has a three-dimensional periodic structure. Specifically, the light control layer 12 is composed of a colloidal crystal film containing colloidal crystals.

[0138] Thus, light incident from the light-transmitting component 11 onto the light control layer 12 is diffracted through the three-dimensional periodic structure of the light control layer 12, producing diffracted light of a specific wavelength corresponding to the angle. Therefore, light of a specific wavelength that varies depending on the viewing angle can be extracted from the light guide 10.

[0139] For example, using a light control layer 12 with Figure 3B The colloidal crystal film R, showing a reflectance spectrum, allows white light to be incident from the light source 20 onto the light-transmitting component 11. When the white light is incident on the light control layer 12, diffracted light, including red, green, and blue light, is generated in the light control layer 12. This diffracted light contains wavelengths from the blue region to the red region. Thus, depending on the viewing angle, the light guide 10 is perceived as red, green, or blue.

[0140] This invention, which involves a light-transmitting component 11 on which a colloidal crystal film is formed on the first main surface 11b, allows light to be incident on the first end surface 11a of the light-transmitting component 11, and extracts light of a specific wavelength depending on the angle. This is a novel invention discovered by the inventors that did not exist before.

[0141] Furthermore, it is known that the light control layer 12, which is made of a colloidal crystal film, can extract light with a shorter wavelength than the positive reflection wavelength. Therefore, a light control layer 12 using a [missing information - likely a specific material or process] is suitable. Figure 3A The colloidal crystal film G, showing a reflectance spectrum, receives white light from the light source 20 and directs it onto the light-transmitting component 11. When the white light reaches the light control layer 12, it generates diffracted green and blue light. Depending on the viewing angle, the light guide 10 appears green or blue. However, no diffracted red light is generated in the light control layer 12, so the red light does not escape from the light control layer 12 and is contained within the light-transmitting component 11. Furthermore, in this embodiment, the red light contained within the light-transmitting component 11 exits from the second end face 11d of the light-transmitting component 11.

[0142] Therefore, according to the light-emitting device 1 of this embodiment, light can be extracted using a new extraction method. This new extraction method involves selectively confining light of a specific wavelength within the light-transmitting member 11 through the light control layer 12, and then exposing other specific wavelengths of light to the outside from a different location on the light-transmitting member 11 than where the light control layer 12 is located. Thus, light emitted from the light source 20 can be separated according to wavelength. In this case, by transmitting the confined light, a light-emitting device that functions as both an illumination device and a light transmission device can be realized.

[0143] This knowledge, which allows specific wavelengths to be emitted from the colloidal crystal film and other specific wavelengths to be blocked by adjusting the composition of the colloidal crystal film when light is incident on the first end face 11a of the light-transmitting component 11 on the first main surface 11b, is a novel knowledge discovered by the inventors that was not previously known.

[0144] Furthermore, as can be seen from the light-emitting device 1 in this embodiment, it is not only possible to extract light of different specific wavelengths or block light of specific wavelengths depending on the viewing angle, but also to improve the light extraction efficiency as described above. In other words, light can be extracted using a new extraction method that can both improve the light extraction efficiency and extract light of different specific wavelengths or block light of specific wavelengths depending on the viewing angle.

[0145] The knowledge that light extraction efficiency can be improved when light is incident on the first end face 11a of the light-transmitting component 11, on the first main surface 11b where a colloidal crystal film has been formed, is a novel knowledge discovered by the inventors that was not previously known.

[0146] Furthermore, colloidal crystal films can be formed by coating, making it easy to form a large-area light control layer 12. Therefore, by using colloidal crystal films, the light-emitting device 1 can be easily scaled up. Moreover, colloidal crystal films can be formed without special fine processing, making them inexpensive to produce. Therefore, it is possible to manufacture a light-emitting device 1 whose color changes with the viewing angle at low cost.

[0147] Furthermore, the thickness of the light control layer 12, which is made of colloidal crystal film, can be between 5 μm and 100 μm.

[0148] If the colloidal crystal film is too thin, it is difficult to obtain diffraction-based optical effects. On the other hand, if the colloidal crystal film is too thick, it is difficult to periodically arrange nanoparticles, and the transmittance of the colloidal crystal film decreases. Therefore, the appearance and light extraction efficiency deteriorate. From this point of view, the thickness of the light control layer 12 formed by the colloidal crystal film is preferably 5 μm or more and 100 μm or less.

[0149] Furthermore, as described above, the colloidal crystal film constituting the light control layer 12 has a specific positive reflection wavelength and a certain range of reflection wavelength regions. In this case, in this embodiment, the reflection wavelength region and positive reflection wavelength of the colloidal crystal film are changed by changing the average particle size of the nanoparticles 12a contained in the light control layer 12, but this is not limited to this. For example, the positive reflection wavelength and reflection wavelength region of the colloidal crystal film can be changed by changing the concentration of the nanoparticles 12a contained in the colloidal crystal film (light control layer 12), or by changing the material of the nanoparticles 12a contained in the colloidal crystal film (light control layer 12), or by using multiple nanoparticles 12a with different average particle sizes, or by combining these factors. In other words, the reflection wavelength region and positive reflection wavelength of the colloidal crystal film can be arbitrarily designed. In this case, as described above, for colloidal crystal films, it is possible to extract light with a shorter wavelength than the positive reflection wavelength. For example, if a large color change in visible light is desired, it is sufficient to form a colloidal crystal film with a reflection wavelength region from the red region to the near-infrared region (610nm to 900nm). If a small degree of color change is desired, it is sufficient to form a colloidal crystal film with a reflection wavelength region from the blue-green region to the orange region (500nm to 600nm).

[0150] Furthermore, the particle arrangement structure of the colloidal crystal in the colloidal crystal film can be a three-dimensional periodic structure with complete periodicity or a three-dimensional periodic structure without complete periodicity. In the case of a completely periodic colloidal crystal, strong diffracted light in a specific direction can be generated according to the relationship between wavelength and particle arrangement period, resulting in a light-emitting device with significant color changes depending on the viewing angle. On the other hand, when the colloidal crystal is not a completely periodic structure, and some of the periods are appropriately disordered, the diffracted light generated in a specific direction is weaker, resulting in a device with smaller color changes.

[0151] Furthermore, in this embodiment, the concept of colloidal crystals in the colloidal crystal film may also include colloidal solid solutions. A colloidal solid solution refers to nanoparticles that have been colloidally crystallized and possess a crystal structure similar to a solid solution. In other words, the nanoparticles, acting as colloidal particles, are formed into an ordered arrangement, becoming an aggregate that resembles a solid solution.

[0152] Furthermore, in this embodiment, the light control layer 12 is formed directly on the light-transmitting component 11, but it is not limited thereto. For example, as the light control layer 12, a light control sheet in which a light control film made of colloidal crystal film is formed on a transparent substrate such as a transparent film can be used, and the light control sheet can be attached to the light-transmitting component 11 by means of an adhesive or the like.

[0153] Furthermore, in this embodiment, the light control layer 12 is formed over the entire surface of the first main surface 11b of the light-transmitting member 11, but it is not limited thereto. The light control layer 12 may be formed on a portion of the surface of the light-transmitting member 11. For example... Figure 19 The light-emitting device 1A shown in (a) can use a light guide 10A in which a rectangular light control layer 12A is formed on a portion of the first main surface 11b of the light-transmitting member 11. Alternatively, it can also be as follows: Figure 19 The light-emitting device 1B shown in (b) can be formed by a light guide 10B with a light control layer 12B having a pattern such as text or graphics by using a portion of the first main surface 11b of the light-transmitting component 11.

[0154] Furthermore, in this embodiment, the light control layer 12 disposed on the light-transmitting component 11 is any one of the colloidal crystal film G and the colloidal crystal film R, but is not limited thereto. For example... Figure 19 The light-emitting device 1C shown in (c) can use a light guide 10C in which a first light control layer 12R made of a colloidal crystal film R and a second light control layer 12G made of a colloidal crystal film G are formed on the first main surface 11b of the light-transmitting member 11, and the light control layers 12C are arranged laterally. Alternatively, as Figure 19 The light-emitting device 1D shown in (d) can utilize a light guide 10D in which a multilayer film consisting of a first light control layer 12R made of a colloidal crystal film R and a second light control layer 12G made of a colloidal crystal film G is formed on the first main surface 11b of the light-transmitting member 11. In other words, as the light control layer 12C, a multilayer film consisting of multiple light control films, each having wavelength selectivity of reflection, can be used. This enables a light-emitting device with rich color variations depending on the viewing angle.

[0155] (Implementation Method 2)

[0156] Next, utilize Figure 20 The light-emitting device 1E involved in Embodiment 2 is described. Figure 20 This is a cross-sectional view of the light-emitting device 1E in Embodiment 2.

[0157] like Figure 20 As shown, the light-emitting device 1E in this embodiment is constructed in the light-emitting device 1 of the above embodiment 1, wherein a reflective part is provided on the second main surface 11c of the light-transmitting member 11. The reflective part is a part that reflects the light guided by the light-transmitting member 11 to the first main surface 11b.

[0158] Specifically, the light-emitting device 1E in this embodiment includes a light guide 10E and a light source 20. The light guide 10E has a light-transmitting component 11E and a light control layer 12. A reflective portion is formed in the light-transmitting component 11E to reflect light guided within the light-transmitting component 11E toward the first main surface 11b. In this embodiment, the reflective portion that reflects light guided within the light-transmitting component 11E to the first main surface 11b is a plurality of recesses 11c1 formed on the second main surface 11c of the light-transmitting component 11E.

[0159] Specifically, each of the plurality of recesses 11c1 is a reflecting prism having a reflecting surface that reflects light guided within the light-transmitting member 11E back to the first main surface 11b. Each of the plurality of recesses 11c1 is a tiny recess formed, for example, by surface processing on the second main surface 11c of the light-transmitting member 11E using a laser or etching method. As an example, the cross-sectional shape of each of the plurality of recesses 11c1 is triangular, such as a conical, triangular prism, triangular pyramid, or square pyramid recess. Furthermore, the light-transmitting member 11E in this embodiment, except for having the recesses 11c1, has the same structure as the light-transmitting member 11 in Embodiment 1 described above.

[0160] Thus, the light-emitting device 1E in this embodiment, like the light-emitting device 1 in Embodiment 1 above, has a light control layer 12 provided on at least a portion of the surface of the light-transmitting member 11E to form a light guide 10E, and has a light source 20 configured to emit light to the first end face 11a of the light-transmitting member 11E.

[0161] With this structure, the light-emitting device 1E in this embodiment can achieve the same effect as the light-emitting device 1 in Embodiment 1. For example, it can extract light of different specific wavelengths or block light of specific wavelengths depending on the viewing angle, or it can improve the light extraction efficiency.

[0162] Furthermore, in this embodiment, the light-emitting device 1E, as a reflective portion that reflects light guided within the light-transmitting member 11E to the first main surface 11b, has a plurality of recesses 11c1 formed on the second main surface 11c of the light-transmitting member 11E. Therefore, compared to the light-emitting device 1 in Embodiment 1 described above, the amount of light incident from the light-transmitting member 11 onto the light control layer 12 can be increased, thus increasing the amount of light extracted from the light control layer 12 side to the outside of the light guide 10. Therefore, compared to the light-emitting device 1 in Embodiment 1 described above, the light extraction efficiency of the light-emitting device 1E can be further improved.

[0163] In addition, in this embodiment, such as Figure 21 As shown in (a), multiple recesses 11c1 are formed in a dotted manner on the entire second main surface 11c in a uniform and equidistant manner, but are not limited thereto. For example... Figure 21 As shown in (b) and (c), multiple recesses 11c1 can be formed on a portion of the second main surface 11c by varying the density distribution, etc. For example, in this case, as Figure 21 As shown in (b), a region with a recess 11c1 and a region without a recess 11c1 can be provided in the second main surface 11c. This increases the amount of light emitted from the portion of the light control layer 12 (light guide 10E) opposite to the region with the recess 11c1, thereby partially improving the brightness of the light-emitting device 1E. On the other hand, Figure 21 As shown in (c), multiple recesses 11c1 can be formed in such a way that the density distribution of the recesses 11c1 changes from sparse to dense as they move further away from the light source 20. This allows for uniform light extraction from the entire light guide 10E, improving the brightness uniformity of the light-emitting device 1E. Furthermore, as... Figure 21 As shown in (d), when the light-transmitting component 11E is film-shaped, a recess 11c1 can be formed on the second main surface 11c of the curved surface. This allows for a partial change in the brightness of the light-emitting device 1E. By adjusting the pattern of the multiple recesses 11c1, light can be extracted uniformly from the entire light guide 10E, or the brightness can be partially increased to extract light, or the amount of extracted light can be adjusted according to the location.

[0164] Furthermore, in this embodiment, a plurality of recesses 11c1 formed on the second main surface 11c of the light-transmitting member 11E are used as a reflective portion to reflect light guided within the light-transmitting member 11E toward the first main surface 11b, but this is not a limitation. For example, a plurality of reflective dots printed on the second main surface 11c of the light-transmitting member 11E can be used as a reflective portion to reflect light guided within the light-transmitting member 11E toward the first main surface 11b.

[0165] (Modified Example)

[0166] The light-emitting device and the like of the present invention have been described above based on embodiments 1 and 2, but this disclosure is not limited to the above embodiments 1 and 2.

[0167] For example, in embodiments 1 and 2 described above, the light control layer 12 is formed only on one surface of the first main surface 11b of the light-transmitting components 11 and 11E, but it is not limited to this. Specifically, as Figure 22In the illustrated light-emitting device 1F, the light control layer 12 can be respectively disposed on both the first main surface 11b and the second main surface 11c of the light-transmitting member 11. In other words, in this modified example, the light guide 10F of the light-emitting device 1F has a structure in which the light control layer 12 is disposed on both the first main surface 11b and the second main surface 11c of the light-transmitting member 11. With this structure, the extraction efficiency of light of a specific wavelength extracted according to the viewing angle can be improved. Furthermore, when light of a specific wavelength is emitted from the light control layer 12 and other specific wavelengths are blocked from transmission, the light blocking effect can be improved. In addition, the light control layer 12 formed on the first main surface 11b and the light control layer 12 formed on the second main surface 11c can be the same or different. For example, the light control layer 12 formed on the first main surface 11b and the light control layer 12 formed on the second main surface 11c can both be colloidal crystal film R or colloidal crystal film G. Alternatively, the light control layer 12 formed on the first main surface 11b can be one of colloidal crystal film R and colloidal crystal film G, and the light control layer 12 formed on the second main surface 11c can be the other of colloidal crystal film R and colloidal crystal film G.

[0168] Furthermore, in embodiments 1 and 2 described above, there is only one light source 20, but there can be multiple light sources 20. In this case, such as Figure 23 as well as Figure 24 The light-emitting device 1G shown uses two light sources 20. One light source 20 is positioned opposite the first end face 11a of the light-transmitting member 11, and the other light source 20 is positioned opposite the second end face 11d of the light-transmitting member 11. Thus, light is incident on the light-transmitting member 11 from both the first end face 11a and the second end face 11d, making the color change of the light extracted from the light guide 10 symmetrical from left to right.

[0169] Or such as Figure 25 The light-emitting device 1H shown can be configured to surround the four end faces of the light-transmitting member 11 with four light sources 20. Specifically, in the light-transmitting member 11, each light source 20 can be arranged such that the first end face 11a (left end face), the second end face 11d (right end face), the third end face (upper end face), and the fourth end face (lower end face) are respectively opposite each other. Thus, light can be incident on the light-transmitting member 11 from the four end faces (upper, lower, left, and right), so that the color change of the light extracted from the light guide 10 can be made symmetrical from top to bottom and left to right.

[0170] Furthermore, in embodiments 1 and 2 described above, the optical axis of the light source 20 is configured to be parallel to the first main surface 11b of the light-transmitting member 11, and the optical axis of the light source 20 remains unchanged, but is not limited to this. For example... Figure 26The illustrated light-emitting device 1I may include a light axis adjustment mechanism 40 for adjusting the light axis of the light source 20. The light axis adjustment mechanism 40 is, for example, a drive device capable of rotating the housing 30 containing the light source 20, and is configured using an actuator or the like. By rotating the housing 30 through the light axis adjustment mechanism 40, the orientation of the light axis of the light source 20 is adjusted, thereby adjusting the orientation of the light incident from the light source 20 onto the first end face 11a of the light-transmitting member 11. This change in the orientation of the light axis of the light source 20 causes a change in the color of the light extracted from the light guide 10. Therefore, by changing the orientation of the light axis of the light source 20, the color of the light emitted from the light guide 10 can be changed without changing the viewing angle. In other words, with the light-emitting device 1I in this modified example, even when viewed from the same viewpoint, the color of the emitted light is perceived to change. In other words, different specific wavelengths of light can be extracted without changing the viewing angle. Furthermore, by changing the orientation of the optical axis of the light source 20, light that could not be extracted through total internal reflection can now be extracted, thus further improving light extraction efficiency. Additionally, although not shown, a variable light distribution mechanism can be used to change the light distribution of the light emitted from the light source 20 without changing the orientation of its optical axis, allowing the color of the light emitted from the light guide 10 to be changed without altering the viewing angle. In other words, by changing the light distribution angle of the light emitted from the light source 20 without changing its optical axis, different specific wavelengths of light can be extracted depending on the viewing angle.

[0171] Furthermore, in embodiments 1 and 2 described above, the light-transmitting component 11 is a flat substrate, but it is not limited to this. For example... Figure 27 The light-emitting device 1J shown uses a rod-shaped component as the light-transmitting member 11J, and the light guide 10J can be used as a rod-shaped light guide rod. In this case, the light control layer 12 can be formed on the entire side surface of the rod-shaped light-transmitting member 11J to form a cylindrical shape, but it can also be formed on a part of the side surface of the rod-shaped light-transmitting member 11J. In addition, the rod-shaped light-transmitting member 11J is not limited to a rigid, slender cylinder, but can also be flexible like an optical fiber. By forming the rod-shaped light guide 10J in this way, a light-emitting device 1J with a high degree of aesthetic design can be achieved by bending it into a curved shape. Furthermore, a colloidal crystal film G or the like is used as the light control layer 12, so that specific wavelengths of light incident on the light-transmitting member 11J are emitted from the light control layer 12, and other specific wavelengths of light are selectively confined within the light-transmitting member 11J and transmitted, emanating from the second end face 11d of the light-transmitting member 11J. Therefore, a light-emitting device 1J is capable of functioning as both an illumination device that illuminates light with a specific wavelength and a light transmission device that transmits light of other specific wavelengths. In this case, the light-transmitting component 11J of the light guide 10J becomes a light waveguide (light transmission path).

[0172] Furthermore, in embodiments 1 and 2 described above, the light control layer 12 is the outermost layer, and the outer surface (light extraction surface) of the light control layer 12 is the exposed boundary surface between it and the air layer, but this is not the only limitation. For example... Figure 28 The light-emitting device 1K shown can have a diffusion layer 50 formed on the outer surface (light extraction surface) of the light control layer 12. The diffusion layer 50 is, for example, a milky-white diffusion film in which incident light is scattered and reflected microparticles. By forming the diffusion layer 50 on the outer surface of the light control layer 12, light diffracted by the light control layer 12 is extracted to the outside after being diffused by the diffusion layer 50. Therefore, it is possible to make the gradation of color change based on angle gradual.

[0173] In this case, such as Figure 29 The light-emitting device 1L shown can further have a reflective sheet 60 attached to the outer surface of the diffusion layer 50. Thus, the light diffracted in the light control layer 12 and diffused in the diffusion layer 50 is reflected by the reflective sheet 60, so the light from the diffusion layer 50 side of the light-transmitting member 11 is not extracted, and the light is extracted from the second main surface 11c of the light-transmitting member 11.

[0174] Furthermore, in embodiments 1 and 2 described above, white light emitted from the light source 20 is incident on the transparent light-transmitting component 11, thereby causing the white light to be incident on the light control layer 12, but this is not the only possibility. For example... Figure 30 The illustrated light-emitting device 1M uses a blue light-emitting element 21M, which emits blue light, as the light-emitting element 21M of the light source 20M, and a fluorescent plate made of a phosphor-containing resin 11M2 containing a yellow phosphor 11M1, as the light-transmitting component 11M of the light guide 10M. In this case, the yellow phosphor 11M1 within the light-transmitting component 11M is excited to emit yellow light by the blue light emitted from the light source 20M and incident on the light-transmitting component 11M. The blue light from the light source 20M mixes with the yellow light from the yellow phosphor 11M1, generating white light in the light-transmitting component 11M. The white light generated in this light-transmitting component 11M is incident on the light control layer 12 and diffracted, extracting specific wavelengths of light from the light guide 10M that vary depending on the viewing angle. Furthermore, white light can be generated not only through blue light-emitting elements and yellow phosphors, but also through combinations of blue light-emitting elements, red phosphors, and green phosphors, or through combinations of UV light-emitting elements that emit ultraviolet light and multiple types of phosphors. Additionally, the phosphor can be either a fluorescent pigment or a fluorescent dye.

[0175] Furthermore, in embodiments 1 and 2 described above, the light guide 10 is composed of a light-transmitting component 11 and a light control layer 12 disposed on the surface of the light-transmitting component 11, but it is not limited to this. For example... Figure 31The light-emitting device 1N shown, and the light guide 10N, can be composed of a light-transmitting component 11N and a plurality of nanoparticles 12a contained in the light-transmitting component 11N. Specifically, the light guide 10N is a bulk body containing a plurality of nanoparticles 12a as colloidal crystals. In addition, the light-transmitting component 11N is, for example, made of a light-transmitting resin material.

[0176] Furthermore, in embodiments 1 and 2 described above, the second main surface 11c of the light-transmitting component 11 is exposed to the outside, but this is not the only limitation. For example... Figure 32 In the illustrated light-emitting device 1O, the second main surface 11c of the light-transmitting member 11 is partially covered by a portion of the frame 30O. In this case, the portion of the frame 30O covering the second main surface 11c of the light-transmitting member 11 can be light-reflective. Therefore, the portion of the frame 30O covering the second main surface 11c of the light-transmitting member 11 can function as a reflective portion, reflecting light guided by the light-transmitting member 11 towards the first main surface 11b. Thus, similar to Embodiment 2 described above, the amount of light incident from the light-transmitting member 11 onto the light control layer 12 can be increased, thereby increasing the amount of light extracted from the light control layer 12 side to the outside of the light guide 10.

[0177] Alternatively, the light may not be reflected by a portion of the frame 30O and guided within the light-transmitting component 11, but rather... Figure 33 The light-emitting device 1P shown has a reflective sheet 70 disposed between the portion of the frame 30O covering the second main surface 11c of the light-transmitting member 11 and the light-transmitting member 11. In other words, the reflective sheet 70, which is in contact with the second main surface 11c of the light-transmitting member 11, can be disposed as a reflective part that reflects the light guided by the light-transmitting member 11 toward the first main surface 11b. In this case, the amount of light extracted from the light guide 10 on the side of the light control layer 12 can also be increased. In addition, the reflective sheet 70 can be made of white resin, or it can be a sheet with a metal film formed on it or the metal sheet itself, or it can be a prism sheet with a reflective prism formed on it.

[0178] Furthermore, in embodiments 1 and 2 described above, the first end face 11a of the light-transmitting component 11 is perpendicular to the first main face 11b, but this is not the only limitation. For example... Figure 34 The light-emitting device 1Q shown, and the light-transmitting component 11Q of the light guide 10Q, can have a shape with its ends cut off. Specifically, the end of the light-transmitting component 11Q has an inclined portion 11Q1, and the first end face 11a becomes an inclined surface that is inclined relative to the first main surface 11b. In this case, the light source 20 can be arranged in such a way that the optical axis of the light source 20 is perpendicular to the inclined surface, i.e., the first end face 11a.

[0179] Furthermore, in embodiments 1 and 2 described above, the first end face 11a of the light-transmitting member 11 is a flat surface, but it is not limited to this. For example... Figure 35 The light-emitting device 1R shown has a recess 11R1 with an inclined surface formed on the first end face 11a of the light-transmitting member 11R of the light guide 10R, which is recessed towards the inside of the light-transmitting member 11R. This suppresses the reflection of light emitted from the light source 20 at the first end face 11a, thus increasing the amount of light from the light source 20 incident on the light-transmitting member 11R. In other words, the incident efficiency of light from the light source 20 onto the light-transmitting member 11R is improved. Consequently, the amount of light extracted from the light guide 10R to the outside is increased, improving the light extraction efficiency of the light-emitting device 1R.

[0180] Furthermore, in embodiments 1 and 2 described above, a colloidal crystal film containing colloidal crystals was used as the light control layer 12 having a three-dimensional periodic structure, but it is not limited to this. For example, the light control layer 12 may also have a three-dimensional periodic structure such as a diffraction grating that generates diffracted light whose color changes according to the viewing angle. However, the diffraction grating for generating diffracted light, as described in embodiment 1, requires precise microfabrication, thus increasing the cost. On the other hand, a colloidal crystal film can be formed simply by coating, so even large areas can be manufactured at low cost. Therefore, it is preferable to use a colloidal crystal film containing colloidal crystals as the light control layer 12.

[0181] Furthermore, in embodiments 1 and 2 described above, a single light source 20 is used, allowing light emitted from the light source 20 to enter the light-transmitting member 11 through the first end face 11a. However, this is not a limitation. For example, light emitted from the single light source 20 can enter the light-transmitting member 11 through the second end face 11d, or through the first main face 11b or the second main face 11c. Therefore, the light source 20 may not be positioned opposite the first end face 11a of the light-transmitting member 11, but may be positioned opposite the second end face 11d, the first main face 11b, or the second main face 11c of the light-transmitting member 11.

[0182] Furthermore, in embodiments 1 and 2 described above, the light source 20 is a white light source with continuous light intensity over a wide wavelength range, but it is not limited to this. For example, the light source 20 may emit light of a single wavelength with a specific peak wavelength, or light of multiple wavelengths including several specific peak wavelengths. For example, the light source 20 may emit light of a single red wavelength, or it may emit white light including three wavelengths with peak wavelengths of red, green, and blue. In addition, when the light emitted from the light source 20 is white light, the color of the extracted light (diffracted light) can vary depending on the viewing angle. In other words, the color gradation corresponding to the viewing angle can be visually observed. On the other hand, when the light emitted from the light source 20 is light of a single wavelength, there is no color change to the extent that can be visually observed by the user, and light is extracted only at an angle corresponding to a single wavelength. Thus, it is possible to realize a light-emitting device that can be seen emitting light only at an angle corresponding to a single wavelength.

[0183] Furthermore, in embodiments 1 and 2 described above, the light source 20 is configured to emit white light through a blue LED chip and a yellow phosphor, but it is not limited to this. For example, it may be configured to emit white light by using a phosphor-containing resin that includes red and green phosphors, instead of a yellow phosphor, and combining it with a blue LED chip.

[0184] Furthermore, in embodiments 1 and 2 described above, the light-emitting element 21 of the light source 20 uses a blue LED chip that emits blue light, but it is not limited to this. For example, the light-emitting element 21 may also use an LED chip that emits light other than blue. For example, the light-emitting element 21 may use an LED chip that emits ultraviolet light. In this case, as phosphor particles, a combination of phosphors that emit the three primary colors (red, green, and blue) can be used. Furthermore, a phosphor is used as a wavelength conversion component, but wavelength conversion components other than phosphors may also be used. For example, as a wavelength conversion component, materials such as semiconductors, metal complexes, organic dyes, and pigments can be used, which contain substances that absorb light of a certain wavelength and emit light of a different wavelength than the absorbed light.

[0185] Furthermore, in embodiments 1 and 2 described above, the light source 20 is an LED module using LEDs, but it is not limited to this. For example, the light source 20 can be a solid-state light-emitting element other than LEDs, such as a semiconductor laser or an organic electroluminescence (Electroluminescence) lamp, or a fluorescent lamp such as a cold cathode fluorescent lamp (CCFL). The light source 20 can be any form of light source as long as it can incident light onto the light-transmitting component 11.

[0186] Furthermore, the light-emitting device in embodiments 1, 2, and their variations can be used as a lighting device, for example. In this case, by using the light-emitting device as a lighting device, a lighting system having one or more lighting devices can be realized. Thus, the color of the illumination light changes depending on the angle from which the lighting device is viewed, thereby enabling spatial representation.

[0187] Alternatively, the light-emitting device can be used as a light transmission device, thereby enabling an optical communication system with more than one light transmission device. In this way, the light extracted from the light-emitting device 1 can be used as light for various purposes other than illumination.

[0188] Furthermore, in the light-emitting devices of Embodiments 1, 2, and their variations, when no light is emitted from the light source 20 (when the light source is off), the light guide becomes transparent, thus allowing the opposite side to be seen through the light guide (transparent state). This is because the light control layer formed by the colloidal crystal film does not reflect light except for specific wavelengths (in other words, it is transparent). On the other hand, in the light-emitting devices of Embodiments 1, 2, and their variations, when light is emitted from the light source 20 (when the light source is on), the light guide emits light, and light is extracted from the light guide, thus making the opposite side invisible due to the light guide emitting light (light-blocking state). As described above, the light control layer formed by the colloidal crystal film allows the viewing of specific wavelengths of color. Thus, in the light-emitting devices of Embodiments 1, 2, and their variations, the conduction / cut-off of visual information such as the transparent state and the light-blocking state can be easily switched using electrical signals. Therefore, the light-emitting devices of Embodiments 1, 2, and their variations can be used as partitions or the like for visually dividing space. In particular, they can extract light of specific wavelengths according to angles, thus making them suitable as partitions with excellent aesthetic design.

[0189] Furthermore, any forms obtained by implementing the above embodiments through various modifications conceived by those skilled in the art, as well as forms achieved by arbitrarily combining the constituent elements and functions of the above embodiments without departing from the spirit of this disclosure, are all included in this invention.

[0190] Symbol Explanation

[0191] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1J, 1K, 1L, 1M, 1N, 1O, 1P, 1Q, 1R Light-emitting devices

[0192] 10, 10A, 10B, 10C, 10D, 10E, 10F, 10J, 10M, 10N, 10Q, 10R light guides

[0193] 11, 11E, 11J, 11M, 11N, 11Q, 11R Light-transmitting components

[0194] 11a First end face

[0195] 11b First Main Page

[0196] 11c Second Main Face

[0197] 11c1 Recessed part (reflective part)

[0198] 12, 12A, 12B, 12C, 12D Light Control Layers

[0199] 20, 20M light source

[0200] 40 Optical axis adjustment mechanism

[0201] 70 Reflective sheet (reflective part)

Claims

1. A light-emitting device, The light-emitting device comprises: A light guide having a light-transmitting component and a light control layer, the light-transmitting component being transparent at least in the visible light region, and the light control layer being disposed on at least a portion of the surface of the light-transmitting component; and A light source emits light onto at least one end face of the light-transmitting component. The light control layer has a colloidal crystal and has wavelength selectivity. The colloidal crystal is composed of multiple nanoparticles arranged periodically in three axes: the 1-axis direction (thickness direction of the light-transmitting component) and the 2-axis direction (parallel to the surface of the light-transmitting component). The wavelength selectivity means that the wavelength of the reflected light depends on the incident angle of the incident light.

2. The light-emitting device as described in claim 1, The light-transmitting component is a substrate having a first main surface and a second main surface opposite to the first main surface. The light control layer is disposed on the first main surface.

3. The light-emitting device as described in claim 2, A reflective portion is provided on the second main surface of the substrate, which reflects light guided on the substrate toward the first main surface.

4. The light-emitting device as described in claim 3, The reflective portion is a plurality of recesses formed on the second main surface of the substrate.

5. The light-emitting device as described in claim 3, The reflective portion is a reflective sheet that is in contact with the second main surface of the substrate.

6. The light-emitting device as described in claim 1, The light-transmitting component is a substrate having a first main surface and a second main surface opposite to the first main surface. The light control layer is provided on the first main surface and the second main surface respectively.

7. The light-emitting device as described in any one of claims 1 to 6, The light control layer is a laminated film consisting of multiple light control films, each having the wavelength selectivity of the reflection.

8. The light-emitting device as described in any one of claims 1 to 6, The light control layer has a three-dimensional periodic structure.

9. The light-emitting device according to any one of claims 1 to 6, The thickness of the light control layer is between 5 μm and 100 μm.

10. The light-emitting device according to any one of claims 1 to 6, The light source includes light-emitting diodes.

11. The light-emitting device according to any one of claims 1 to 6, The light-emitting device includes an optical axis adjustment mechanism for adjusting the optical axis of the light source.

12. The light-emitting device according to any one of claims 1 to 6, The light-emitting device includes a variable light distribution mechanism for altering the light distribution of light emitted from the light source.

13. A lighting system comprising, as a lighting device, a light-emitting device according to any one of claims 1 to 12.

14. An optical communication system comprising, as an optical transmission device, the light-emitting device according to any one of claims 1 to 12.

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