Light-emitting device and lighting device

Abstract

Provided are a light-emitting device and a lighting device with high light utilization efficiency. The light-emitting device includes: a light source having a light-emitting element and having an optical axis extending in a first direction; and an optical element. The surface of the optical element has: an incident region on which light emitted from the light source is incident; a first region that reflects first light entering the optical element from the incident region toward the light source; an annular second region surrounding the first region; and an annular third region surrounding the incident region. The first region reflects, toward the light source, the first light that reaches a central region overlapping the light-emitting element as viewed from the first direction in the first region, and the first light that reaches an outer region located outside the central region, among the first light. The second region reflects second light entering the optical element from the incident region. The third region reflects the second light reflected by the second region toward the second region.

Description

Technical Field

[0001] The embodiment relates to a light-emitting device and a lighting device. Background Art

[0002] In a lighting device for dental treatment, in order to reliably illuminate a patient's oral cavity and reduce the light reaching the patient's eyes, the illuminance and illuminance distribution are specified according to ISO standards. Even if the lighting device for dental treatment satisfies the ISO standards, it is preferable to be able to further reduce the glare felt by the patient. In addition, in the lighting device for dental treatment, reduction of power consumption is required. In order to reduce glare and power consumption, it is effective to reduce stray light and make the light emitted from the light-emitting element reach the target area efficiently.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-137979

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2013-211098 Summary of the Invention

[0007] Technical Problem to be Solved by the Invention

[0008] An object of the embodiment is to provide a light-emitting device and a lighting device with high light utilization efficiency.

[0009] Means for Solving the Problem

[0010] The light-emitting device of the embodiment includes a light source having an optical axis extending in a first direction and an optical element. The light source has a light-emitting element. The surface of the optical element has: an incident area for the light emitted from the light source to enter; a first area for reflecting the first light entering the optical element from the incident area toward the light source; a ring-shaped second area surrounding the first area; and a ring-shaped third area surrounding the incident area. The first area reflects the first light in the first light, the first light reaching the central area overlapping with the light-emitting element when viewed in the first direction from the first area and the first light reaching the outer area located outside the central area, toward the light source. The second area reflects the second light entering the optical element from the incident area. The third area reflects the second light reflected by the second area back to the second area. The light reflected in the third area exits from the second area. The first light and the second light include the light emitted from the light source and the third light reflected by the light source after being reflected by the first area.

[0011] The lighting device of the embodiment has one or more of the above-described light-emitting devices.

[0012] Advantages of the Invention

[0013] According to the embodiments, a light-emitting device and a lighting device with high light utilization efficiency can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a top view showing the light-emitting device of the first embodiment.

[0015] Figure 2 It shows Figure 1 A partially enlarged top view of Region II of

[0016] Figure 3 It is a bottom view showing the light-emitting device of the first embodiment.

[0017] Figure 4 It is a perspective view showing the light-emitting device of the first embodiment.

[0018] Figure 5 It is a side view showing the light-emitting device of the first embodiment.

[0019] Figure 6 It is Figure 1 A cross-sectional view taken along line VI-VI shown in

[0020] Figure 7 It is a side view, a cross-sectional view showing the light-emitting device of the first embodiment, and a line showing the cross-section of the third region.

[0021] Figure 8 It is a side view, a cross-sectional view showing the light-emitting device of the first embodiment, and a line showing the cross-section of the third region.

[0022] Figure 9 It is an optical path diagram showing the operation of the light-emitting device of the first embodiment.

[0023] Figure 10 It shows Figure 9 A diagram of Region X of

[0024] Figures 11A to 11F It is a bottom view showing the light-emitting device of the first embodiment, a cross-sectional view taken along line A-A' shown in the bottom view, a cross-sectional view taken along line B-B', a diagram of a part of the light trajectory from the light-emitting device to the irradiation region, and a diagram of the irradiation region in the imaging plane.

[0025] Figure 12 It is an optical path diagram showing the light-emitting device of a modification of the first embodiment.

[0026] Figure 13 It is an optical path diagram showing the light-emitting device of the second embodiment.

[0027] Figure 14 is a partial enlarged optical path diagram of region XIV which represents Figure 13 .

[0028] Figure 15 is a top view of the first region of the light-emitting device according to the second embodiment.

[0029] Figure 16 is a diagram showing an example of the trajectory of light incident on a three-sided right-angled prism.

[0030] Figure 17 is an optical path diagram of the light-emitting device according to a modified example of the second embodiment.

[0031] Figure 18 is a perspective view of the lighting device according to the third embodiment.

[0032] Figure 19 is an optical path diagram showing the operation of the lighting device according to the third embodiment.

[0033] Figure 20 is a perspective view of the lighting device according to the first modified example of the third embodiment, viewed from the first direction side.

[0034] Figure 21 is a perspective view of the lighting device according to the first modified example of the third embodiment, viewed from the side opposite to the first direction.

[0035] Figure 22 is a side view of the lighting device according to the first modified example of the third embodiment.

[0036] Figure 23 is a perspective view of the lighting device according to the second modified example of the third embodiment, viewed from the first direction side.

[0037] Figure 24 is a perspective view of the lighting device according to the second modified example of the third embodiment, viewed from the side opposite to the first direction.

[0038] Figure 25 is a side view of the lighting device according to the second modified example of the third embodiment.

[0039] Figure 26 is a perspective view of the lighting device according to the third modified example of the third embodiment, viewed from the first direction side.

[0040] Figure 27 is a perspective view of the lighting device according to the third modified example of the third embodiment, viewed from the side opposite to the first direction.

[0041] Figure 28 It is a side view of a lighting device showing a third modification of the third embodiment.

[0042] Figure 29 It is a partially enlarged sectional view of a lighting device showing a third modification of the third embodiment.

[0043] Figure 30 It is an optical path diagram of a light-emitting device of the first comparative example.

[0044] Figure 31 It is an optical path diagram of a light-emitting device of the second comparative example.

[0045] Figure 32 It is an optical path diagram of a light-emitting device of the third comparative example.

[0046] Embodiments of the Invention

[0047] <First Embodiment>

[0048] Figure 1 It is a top view of the light-emitting device of this embodiment.

[0049] Figure 2 It is showing Figure 1 a partially enlarged top view of Region II of

[0050] Figure 3 It is a bottom view of the light-emitting device of this embodiment.

[0051] Figure 4 It is a perspective view of the light-emitting device of this embodiment.

[0052] Figure 5 It is a side view of the light-emitting device of this embodiment.

[0053] Figure 6 It is Figure 1 a sectional view taken along line VI-VI shown in

[0054] Figure 7 It is a side view, a sectional view of the light-emitting device of this embodiment, and the line indicating the section.

[0055] Figure 8 It is a side view, a sectional view of the light-emitting device of this embodiment, and the line indicating the section.

[0056] It should be noted that each figure is a schematic structure, with appropriate emphasis or simplification. Additionally, in the figures, even for the same constituent elements, the dimensional ratios and aspect ratios are not necessarily strictly the same. Moreover, as sectional views, sometimes end views showing only the end faces of the section planes are used. The same applies to other figures described later.

[0057] (Schematic Structure of the Light-Emitting Device)

[0058] Hereinafter, the configuration of the light-emitting device according to the present embodiment will be outlined.

[0059] As Figures 1 to 8 shown, the light-emitting device 1 according to the present embodiment includes a light source 10 and an optical element 20. The light source 10 has a light-emitting element 11. The light source 10 has an optical axis C extending in the first direction Z.

[0060] Hereinafter, in this specification, for convenience of explanation, an XYZ orthogonal coordinate system is adopted. The direction in which the optical axis C of the light source 10 extends is taken as the "first direction Z". Further, two directions that are orthogonal to the first direction Z and orthogonal to each other are taken as the "second direction X" and the "third direction Y". Furthermore, in the following description, the first direction Z is also referred to as "up", and the opposite direction of the first direction Z is referred to as "down", but this expression is for convenience and has nothing to do with the direction of gravity. For example, the first direction Z is the main traveling direction of the light emitted from the light-emitting device 1, but as will be described later, when the light-emitting device 1 is used as a dental treatment illumination device, the light emission direction is mostly obliquely downward.

[0061] The surface of the optical element 20 has an incident region 24, a first region 21, a second region 22, and a third region 23. As Figure 9 shown, the light L0 emitted from the light source 10 is incident on the incident region 24. The first region 21 is located on the opposite side of the incident region 24. The first region 21 is larger than the light-emitting element 11 when viewed from the first direction Z. The first region 21 reflects the first light L1 that enters the optical element 20 from the incident region 24 toward the light source 10. When the first region 21 is divided into a central region 21C that overlaps the light-emitting element 11 when viewed from the first direction Z and an outer region 21E located outside the central region 21C, the first region 21 reflects the first light L1 that reaches the central region 21C and the first light L1 that reaches the outer region 21E toward the light source 10 in both directions.

[0062] The second region 22 is an annular region surrounding the first region 21. The second region 22 reflects the second light L2 that enters the optical element 20 from the incident region 24 toward the third region 23. The third region 23 is an annular region surrounding the incident region 24. The third region 23 reflects the second light L2 reflected by the second region 22 back to the second region 22. The light reflected by the third region 23 exits from the second region 22. The first light L1 and the second light L2 include the light L0 emitted from the light source 10 and the third light L3 that is reflected by the first region 21 and then reflected by the light source 10.

[0063] (Detailed configuration of the light-emitting device)

[0064] Next, the configuration of the light-emitting device 1 of the present embodiment will be described in detail. In the following description, there are parts that overlap with the above schematic description. It should be noted that the configuration described below is an example, and the present invention is not limited thereto.

[0065] As Figures 4 to 6 shown, in addition to the above light source 10 and optical element 20, the light-emitting device 1 may also include a substrate 40. The substrate 40 is, for example, a printed circuit board (PCB), such as an aluminum-based rigid board. The light source 10 is mounted on the substrate 40. It should be noted that in Figure 3 , Figure 7 , Figure 8 , the substrate 40 is omitted for easy viewing of the figure.

[0066] As Figure 6 shown, in addition to the light-emitting element 11, the light source 10 may also have a sealing member 12. The light-emitting element 11 is supplied with power via the substrate 40. The light-emitting element 11 is, for example, a light-emitting diode (LED). As Figure 2 and Figure 6 shown, when viewed from the first direction Z, the light-emitting element 11 is rectangular, for example, square. When viewed from the first direction Z, the four sides of the light-emitting element 11 extend in the second direction X and the third direction Y.

[0067] The sealing member 12 is disposed on the light-emitting element 11. The shape of the sealing member 12 is, for example, a dome shape convex in the first direction Z. As Figure 10 shown, the sealing member 12 includes a light-transmitting portion 12a, a reflecting portion 12b, and a wavelength conversion portion 12c. The wavelength conversion portion 12c covers the upper surface of the light-emitting element 11. The reflecting portion 12b covers the side surface of the light-emitting element 11. The light-transmitting portion 12a covers the light-emitting element 11, the reflecting portion 12b, and the wavelength conversion portion 12c. The light-transmitting portion 12a is made of a light-transmissive resin material. The wavelength conversion portion 12c contains a phosphor. For example, when the light-emitting element 11 emits blue light, the phosphor contained in the wavelength conversion portion 12c absorbs a part of the blue light emitted from the light-emitting element 11 and emits yellow light. Thus, the light L0 emitted from the light source 10 is mixed with blue light and yellow light to become white light. It should be noted that the sealing member 12 may not include the reflecting portion 12b.

[0068] As Figures 4 to 6As shown, the optical element 20 is fixed to the substrate 40. The light source 10 is also fixed to the substrate 40, so the optical element 20 is fixed relative to the light source 10. The shape of the optical element 20 is a substantially rotating body with the optical axis C of the light source 10 as the rotation axis. Thus, when viewed from the first direction Z, the shape of the optical element 20 is substantially circular. However, as will be described later, in the third region 23, there is anisotropy between the second direction X and the third direction Y.

[0069] As Figure 3 and Figure 6 shown, the incident region 24 and the third region 23 are arranged on the lower surface of the optical element 20. The incident region 24 is the center of the lower surface of the optical element 20, that is, the region centered on the intersection of the lower surface and the optical axis C. The incident region 24 is a surface including a concave curved surface. A concave portion 25 is defined on the lower surface of the optical element 20 according to the incident region 24. The light source 10 is arranged in the concave portion 25. As Figure 6 shown, in the cross-section including the optical axis C of the light source 10, the depth D of the concave portion 25 is preferably larger than the width W of the opening of the concave portion 25. That is, preferably D > W.

[0070] The third region 23 of the optical element 20 is an annular region surrounding the incident region 24. For example, the third region 23 deviates from the incident region 24. The third region 23 is inclined with respect to the substrate 40 in such a way that the farther it is from the incident region 24, the more it is displaced upward.

[0071] The third region 23 is divided into a plurality of sub-regions 23a along the second direction X. The shape of each sub-region 23a is a strip with the third direction Y as the length direction. Each sub-region 23a does not substantially bend in the second direction X and is substantially flat. Adjacent sub-regions 23a cross each other. Each sub-region 23a bends in the third direction Y in such a way that it continuously displaces along the first direction Z.

[0072] Therefore, as Figure 7 shown, in the cross-section of the third region 23, the XZ cross-section, that is, the first cross-section 23xz with the optical axis C of the light source 10 as the first axis and including the first axis and one second axis orthogonal to the first axis, and the cross-sections parallel to the first cross-section 23xz are each a broken line connected by a plurality of line segments. The second axis extends along the second direction X. The black dots in the first cross-section 23xz indicate the bending points.

[0073] In contrast, as Figure 8 shown, the YZ cross-section in the cross-section of the third region 23, that is, the second cross-section 23yz including the first axis and the third axis orthogonal to the first axis and the second axis, and the cross-sections parallel to the second cross-section 23yz are each a continuous curve. The third axis extends along the third direction Y.

[0074] On the lower surface of the optical element 20, in the region between the incident region 24 and the third region 23, two or more, for example, three convex portions 26 may be provided. In this case, through holes are respectively arranged at positions corresponding to the convex portions 26 in the substrate 40. By passing the three convex portions 26 through the three through holes of the substrate 40 respectively, the optical element 20 is fixed to the substrate 40. It should be noted that in Figure 3 , Figure 7 , Figure 8 , the convex portions 26 are omitted. The optical element 20 may also be fixed to the substrate 40 by other configurations.

[0075] As Figures 1 to 6 shown, the first region 21 and the second region 22 are arranged on the upper surface of the optical element 20. The first region 21 is a region centered on the center of the upper surface of the optical element 20, that is, the intersection of the upper surface and the optical axis C. In the present embodiment, the first region 21 is a convex curved surface, which may be a part of a spherical surface, an aspherical surface, or a curved surface combining a part of a spherical surface and an aspherical surface. The first region 21 is preferably, for example, a part of an aspherical surface centered on a point within the light-emitting element 11. The first region 21 is, for example, a rotational surface with the optical axis C of the light source 10 as the rotation axis, and when observed from the first direction Z, the shape of the convex curved surface is circular.

[0076] The second region 22 is an annular region surrounding the first region 21 and is in contact with the first region 21. The second region 22 is inclined with respect to the substrate 40 in such a manner that it is displaced upward as it is farther away from the first region 21. The angle formed by the substrate 40 and the second region 22 is smaller than the angle formed by the substrate 40 and the third region 23. Therefore, the farther away from the optical axis C, the closer the second region 22 and the third region 23 are, and the thinner the optical element 20 is in the first direction Z. It should be noted that the angle formed by the substrate 40 and the second region 22 is the angle formed by the upper surface of the substrate 40 and the line segment connecting the upper end and the lower end of the second region 22 in a cross-section including the optical axis C. In addition, the angle formed by the substrate 40 and the third region 23 is the angle formed by the upper surface of the substrate 40 and the line segment connecting the upper end and the lower end of the third region 23 in a cross-section including the optical axis C.

[0077] The optical element 20 includes a light-transmitting member 29, a metal member 28, and a reflecting member 27. The light-transmitting member 29 is made of a light-transmitting material, for example, a light-transmitting resin material, and is formed of, for example, polymethyl methacrylate (PMMA). The light-transmitting member 29 constitutes the main body portion of the optical element 20.

[0078] The metal component 28 is, for example, aluminum or silver. The metal component 28 continuously covers the light-transmissive component 29 over the entirety of the first region 21 and the portion of the second region 22 that is in contact with the first region 21. When viewed from the first direction Z, the metal component 28 is circular.

[0079] The reflection component 27 is also, for example, an aluminum thin film or a silver thin film. The reflection component 27 covers the light-transmissive component 29 in the third region 23. When viewed from the first direction Z, the reflection component 27 is annular. It should be noted that, in Figure 7 the cross-sectional view of Figure 8 and the cross-sectional view of

[0080] as shown in Figure 2 for the sake of convenience in illustration, the metal component 28 and the reflection component 27 are omitted.

[0081] (Operation)

[0082] Next, the operation of the light-emitting device 1 of the present embodiment will be described.

[0083] Figure 9 is an optical path diagram showing the operation of the light-emitting device of the present embodiment.

[0084] Figure 10 is a diagram showing Figure 9 region X of

[0085] FIG. 11 is a bottom view of the light-emitting device of the present embodiment ( Figure 11A ), the cross-sectional view taken along line A-A' shown in this bottom view ( Figure 11B ), the cross-sectional view taken along line B-B' ( Figure 11C ), a diagram showing a part of the light trajectory from the light-emitting device to the irradiation region ( Figure 11D , Figure 11E ), and a diagram showing the irradiation region in the imaging plane ( Figure 11F ).

[0086] As shown in Figure 10 , when power is supplied to the light-emitting element 11 via the substrate 40, the light-emitting element 11 emits, for example, blue light. The phosphor contained in the wavelength conversion unit 12c absorbs a part of this blue light and emits, for example, yellow light. As a result, the blue light and the yellow light are mixed, and white light L0 is emitted from the light source 10.

[0087] As Figure 9 and Figure 10 shown, the light L0 emitted from the light source 10 enters the light transmissive member 29 of the optical element 20 via the incident region 24. When the incident region 24 is a concave curved surface, the incident angle of the light L0 with respect to the incident region 24 is stably smaller than the critical angle, so the incident efficiency is improved.

[0088] The light L0 that enters the optical element 20 from the incident region 24 mainly heads towards the first region 21 and the second region 22. The light in the light L0 that heads towards the first region 21 is called the first light L1, and the light that heads towards the second region 22 is called the second light L2.

[0089] The first region 21 is a convex curved surface, and a metal member 28 covering the light transmissive member 29 is disposed in the first region 21, so the first region 21 retro - reflects the first light L1. That is, most of the first light L1 is reflected towards the light source 10 at the interface between the light transmissive member 29 and the metal member 28 in the first region 21. Thus, both the first light L1 that reaches the central region 21C of the first region 21 and the first light L1 that reaches the outer region 21E are reflected towards the light source 10. When the first region 21 is a rotation surface with the optical axis C of the light source 10 as the rotation axis, since the first light L1 is reflected towards the light emitting element 11 in the light source 10, the accuracy of retro - reflection is high.

[0090] Since the second light L2 enters the second region 22 at an incident angle larger than the critical angle, total reflection occurs in the second region 22. The second light L2 totally reflected by the second region 22 heads towards the third region 23. Since a reflection member 27 covering the light transmissive member 29 is disposed in the third region 23, the third region 23 reflects the second light L2 emitted from the second region 22 towards the second region 22. The second light L2 that reaches the second region 22 from the third region 23 enters the second region 22 at an incident angle smaller than the critical angle, so it exits the optical element 20 via the second region 22.

[0091] On the other hand, the first light L1 that is retro - reflected by the first region 21 and returns to the light source 10 is reflected in the light source 10. More specifically, the first light L1 is reflected by the surface of the sealing member 12, or scattered by the phosphor contained in the wavelength conversion unit 12c, or converted into light with a different wavelength by the phosphor contained in the wavelength conversion unit 12c and emitted, or reflected by the surface of the light emitting element 11, or reflected by other components constituting the light source 10. Thus, the light reflected, scattered, emitted, etc. in the light source 10 is collectively referred to as the "third light L3".

[0092] The third light L3 becomes part of the first light L1 and the second light L2 and is reused. In other words, the first light L1 and the second light L2 each include: the light emitted from the light source 10 by causing the light-emitting element 11 to emit light, and the third light L3 that is reflected by the first region 21 and then reflected by the light source 10. The light emitted from the optical element 20 via the second region 22 is referred to as "fourth light L4". The fourth light L4 is the emitted light of the light-emitting device 1.

[0093] As Figure 11A shown, the third region 23 is divided into a plurality of sub-regions 23a along the second direction X. Therefore, in the third region 23, Figure 7 the first cross-section 23xz parallel to the second direction X shown is a broken line, Figure 8 and the second cross-section 23yz parallel to the third direction Y shown is a continuous curve. Thus, the shape of the third region 23 has anisotropy between the second direction X and the third direction Y.

[0094] Therefore, as Figure 11B and Figure 11D shown, with respect to the second direction X, since the angles of reflection by each sub-region 23a are gradually different, the fourth light L4 is diffused. On the other hand, Figure 11C and Figure 11E shown, with respect to the third direction Y, the fourth light L4 emitted from the optical element 20 along the first direction Z is hardly diffused and converges in the imaging plane 200.

[0095] Accordingly, the fourth light L4 is diffused in the imaging plane 200 along the second direction X. As a result, as Figure 11F shown, in the imaging plane 200, the shape of the irradiation region 201 of the fourth light L4 is a substantially rectangular shape in which the length Lx along the second direction X is longer than the length Ly along the third direction Y.

[0096] It should be noted that assuming that there is no such anisotropy in the third region 23 but it is a perfect solid of revolution, the shape of the irradiation region 201 in the imaging plane 200 will reflect the shape of the light-emitting element 11. For example, when the shape of the light-emitting element 11 is square when viewed from the first direction Z, the shape of the irradiation region 201 is also substantially square.

[0097] (Effect)

[0098] In the light-emitting device 1 of the present embodiment, the light L0 emitted from the light source 10 enters the optical element 20 from the incident region 24, is totally reflected in the second region 22, is reflected in the third region 23, and is emitted from the optical element 20 via the second region 22. Thereby, an irradiation region 201 having a specified shape can be formed in the imaging plane 200.

[0099] Moreover, in the first region 21, by reflecting both the first light L1 reaching the central region 21C and the first light L1 reaching the outer region 21E toward the light source 10, these lights can be reflected by the light source 10 and reused. Therefore, in the light-emitting device 1, there is less stray light and the light utilization efficiency is high. Stray light refers to the light that irradiates a region deviated from the irradiation region 201.

[0100] In addition, in the light-emitting device 1, the first region 21 retroreflects the first light L1. As a result, since substantially the whole of the first light L1 is reflected toward the light source 10, stray light can be further reduced and the light utilization efficiency can be further improved.

[0101] Furthermore, by making the first region 21 a convex curved surface, the accuracy of reflecting the first light L1 toward the light source 10 is improved. In addition, by making this curved surface a rotating surface with the optical axis C of the light source 10 as the rotation axis, most of the first light L1 can be reflected toward the light-emitting element 11. As a result, the reflection accuracy of the first light L1 in the first region 21 is further improved. Thereby, stray light is reduced and the light utilization efficiency is improved.

[0102] In addition, by making the incident region 24 concave and disposing the light source 10 in the concave portion 25 defined by the incident region 24, the light-emitting device 1 can be miniaturized in the first direction Z. In addition, in a cross section including the optical axis C of the light source 10, by making the depth D of the concave portion 25 larger than the width W of the opening of the concave portion 25, the light-emitting device 1 can also be miniaturized in the XY plane. Further, by forming the incident region 24 with a concave curved surface, the incident angle when the light L0 emitted from the light source 10 enters the incident region 24 can be made smaller, and the light L0 can be efficiently introduced into the optical element 20. Thereby, stray light is reduced and the light utilization efficiency is improved.

[0103] Furthermore, since the optical element 20 has the metal member 28 covering the light-transmissive member 29 in the first region 21, the first light L1 can be reliably reflected in the first region 21. In addition, by making the metal member 28 continuously cover the first region 21 and a part of the second region 22, the second light L2 can be reliably reflected even in a region where the incident angle of the second light L2 in the second region 22 is relatively small. Further, since the optical element 20 has the reflection member 27 covering the light-transmissive member 29 in the third region 23, the second light L2 can be reliably reflected in the third region 23.

[0104] Further, by making the first cross-section 23xz parallel to the XZ plane in the cross-section of the third region 23 a broken line formed by connecting a plurality of line segments, and making the second cross-section 23yz parallel to the YZ plane a continuous curve, the irradiation region 201 in the imaging plane 200 can be extended along the second direction X. Thus, the ratio of the length Lx in the second direction X to the length Ly in the third direction Y of the irradiation region 201 can be adjusted arbitrarily.

[0105] Further, since the light source 10 has the wavelength conversion unit 12c containing the phosphor, the options for the color of the light L0 are increased. For example, by using an LED that emits blue light, white light L0 can be achieved.

[0106] It should be noted that the shape of the incident region 24 can also be a shape combining a concave surface and a convex surface. For example, a convex portion protruding toward the light source 10 can be provided at the top of the concave portion 25. Thus, since the light incident on the convex portion is condensed onto the first region 21, the first light L1 and the second light L2 can be separated in the incident region 24.

[0107] <Modification of the First Embodiment>

[0108] Figure 12 It is an optical path diagram showing the light-emitting device of this modification.

[0109] In this modification, the same reference numerals are given to the same components as those in the first embodiment, and detailed descriptions thereof are omitted. The same applies to other embodiments and their modifications described later.

[0110] As Figure 12 shown, the difference between the light-emitting device 1a of this modification and the light-emitting device 1 of the first embodiment is that the metal member 28 is only arranged in the first region 21 and not arranged in the second region 22.

[0111] When the positional accuracy of the light source 10 and the optical element 20 and the shape accuracy of the light-transmitting member 29 are sufficiently improved so that the second light L2 incident from the incident region 24 can be reliably totally reflected in the second region 22, the same effects as those of the first embodiment can also be obtained by using this modification. The configurations, operations, and effects other than the above in this modification are the same as those of the first embodiment.

[0112] <Second Embodiment>

[0113] Figure 13 It is an optical path diagram showing the light-emitting device of this embodiment.

[0114] Figure 14 It is showing Figure 13 a partially enlarged optical path diagram of region XIV.

[0115] Figure 15 This is a top view showing the first region of the light-emitting device according to the present embodiment.

[0116] Figure 16 This is a diagram showing the trajectory of light incident on a right-angled prism with three faces.

[0117] As Figures 13 to 16 shown, in the light-emitting device 2 of the present embodiment, the first region 31 of the optical element 20 has a plurality of right-angled prisms 31a with three faces. Each right-angled prism 31a with three faces is composed of three mutually orthogonal reflecting surfaces. In the first region 31, the right-angled prisms 31a with three faces are arranged without gaps. The first region 31 having a plurality of right-angled prisms 31a with three faces is generally flat as a whole. In addition, a metal member 38 is provided in the first region 31. The metal member 38 covers the light-transmissive member 29 in the first region 31. The metal member 38 is, for example, an aluminum thin film or a silver thin film. It should be noted that in Figure 13 and Figure 15 the metal member 38 is omitted.

[0118] In the light-emitting device 2, the first light L1 incident from the incident region 24 into the optical element 20 is incident on any one of the right-angled prisms 31a with three faces in the first region 31. As Figure 16 shown, the first light L1 incident on the right-angled prism 31a with three faces is usually reflected successively by the three reflecting surfaces constituting the right-angled prism 31a with three faces and exits in the direction opposite to the incident direction. It should be noted that depending on the incident direction of the first light L1, it may be reflected by only two or one plane and exit in the direction opposite to the incident direction.

[0119] Thus, when the first region 31 is divided into a central region that overlaps with the light-emitting element 11 when viewed from the first direction Z and an outer region located outside the central region, the first region 31 can reflect the first light L1 reaching the central region and the first light L1 reaching the outer region in two directions to the light source 10. For example, the first region 31 retroreflects the first light L1 to the light source 10. The constitution, operation, and effects other than the above in the present embodiment are the same as those in the first embodiment.

[0120] <Second modification of the second embodiment>

[0121] Figure 17 This is an optical path diagram showing the light-emitting device of this modification.

[0122] As Figure 17 shown, in the light-emitting device 2a of this modification, the imaginary curve connecting the vertices of the plurality of right-angled prisms 31a with three faces arranged in the first region 31 is a convex curve, and a metal member 38 is provided in the first region 31. However, in Figure 17In this case, the metal component 38 is omitted. Thus, the same effects as those of the second embodiment can be obtained. The configurations, operations, and effects other than those described above in this embodiment are the same as those of the second embodiment.

[0123] <Third Embodiment>

[0124] Figure 18 is a perspective view showing the lighting device of this embodiment.

[0125] Figure 19 is an optical path diagram showing the operation of the lighting device of this embodiment.

[0126] This embodiment is a lighting device using the above-described light-emitting device.

[0127] As Figure 18 shown, the lighting device 100 of this embodiment includes one or more light-emitting devices 1 of the first embodiment. It should be noted that the lighting device 100 may instead of the light-emitting device 1, have a light-emitting device 1a which is a modification of the first embodiment, a light-emitting device 2 of the second embodiment, or a light-emitting device 2a which is a modification of the second embodiment.

[0128] The lighting device 100 is a lighting device for dental treatment. In the lighting device 100, a frame-shaped frame 101 and six light-emitting devices 1 are provided. The surface observed from the first direction Z side of the frame 101 is inclined toward the center of the frame 101 in the direction opposite to the first direction Z. The six light-emitting devices 1 are mounted on the frame 101 and power is supplied via the frame 101. It should be noted that the number of the light-emitting devices 1 is not limited to six, and one or more are sufficient.

[0129] As Figure 19 shown, the optical axes C of the plurality of light-emitting devices 1 are inclined with respect to each other and intersect in the imaging plane 200. Thus, the irradiation regions 201 formed by the plurality of light-emitting devices 1 overlap each other. That is, one irradiation region 201 is formed by the plurality of light-emitting devices 1. The distance from the lighting device 100 to the imaging plane 200 is 700 mm according to ISO9680 and 650 mm to 700 mm according to JIS T5753 based on ISO9680.

[0130] It should be noted that between the six light-emitting devices 1, since the optical axes C are inclined with respect to each other, Figure 18 and Figure 19 the XYZ orthogonal coordinates shown are not strictly the same as the Figures 1 to 17 XYZ orthogonal coordinates shown. In Figure 18 and Figure 19 , as the first direction Z, the direction in which the central axis of the frame 101 extends is shown. The same applies to each of the following modification examples.

[0131] According to this embodiment, by adjusting the positional relationship between the patient and the lighting device 100, the irradiation area 201 of the lighting device 100 is positioned in the patient's mouth, the second direction X is made to coincide with the patient's left - right direction, and the third direction Y is made to coincide with the patient's up - down direction. Thus, using the rectangular irradiation area 201 whose length direction is the patient's left - right direction, the patient's oral cavity can be illuminated.

[0132] Moreover, as described above, since the light - emitting device 1 has little stray light, the light reaching the patient's eyes can be reduced, and the situation where the patient feels dazzled can be reduced. In addition, since the light utilization efficiency of the light - emitting device 1 is high, the light utilization efficiency of the lighting device 100 is also high. As a result, power - saving and high - illuminance lighting can be achieved.

[0133] <First Variation of the Third Embodiment>

[0134] Figure 20 It is a perspective view of the lighting device of this variation, and is a view observed from the first direction Z side.

[0135] Figure 21 It is a perspective view of the lighting device of this variation, and is a view observed from the side opposite to the first direction Z.

[0136] Figure 22 It is a side view of the lighting device of this variation.

[0137] As Figures 20 to 22 As shown, in the lighting device 110 of this variation, there is provided an annular frame 111 and six light - emitting devices 1. The frame 111 has an upper surface 111a facing the first direction Z side and a lower surface 111b facing the side opposite to the first direction Z. The surface 111a observed from the first direction Z side of the frame 111 is inclined in the direction opposite to the first direction Z toward the center of the frame 111. That is, the upper surface 111a is displaced more in the first direction Z as it separates more from the central axis C111 of the frame 111.

[0138] Six light - emitting devices 1 are arranged on the upper surface 111a of the frame 111. However, the six light - emitting devices 1 are not arranged at equal intervals along the outer periphery of the frame 111, but three are arranged in each of the regions on both sides of the second direction X in the upper surface 111a. The lower surface of the substrate 40 of each light - emitting device 1 is fixed to the upper surface 111a of the frame 111. The constitution, operation, and effects other than the above in this variation are the same as those of the third embodiment.

[0139] <Second Variation of the Third Embodiment>

[0140] Figure 23 It is a perspective view of the lighting device of this variation, and is a view observed from the first direction Z side.

[0141] Figure 24 It is a perspective view of the lighting device showing this modified example, and is a view observed from the side opposite to the first direction Z.

[0142] Figure 25 It is a side view of the lighting device showing this modified example.

[0143] As Figures 23 to 25 shown, in the lighting device 120 of this modified example, there is provided an annular frame 121 and six light-emitting devices 1. The surface 121a observed from the first direction Z side of the frame 121 and the surface 121b observed from the direction opposite to the first direction Z are inclined toward the center of the frame 121 in the direction opposite to the first direction Z. That is, the upper surface 121a and the lower surface 121b are displaced more in the first direction Z as they are separated more from the central axis C121 of the frame 121. The frame 121 is divided into eight regions along the outer periphery of the frame 121, and through-holes 129 are provided in six regions except for the two regions arranged on both sides in the third direction Y.

[0144] The outer peripheral portion of the upper surface of the optical component 20 of each light-emitting device 1 is fixed to the region surrounding the through-hole 129 in the lower surface 121b of the frame 121. Accordingly, the light-emitting device 1 is arranged on the lower surface 121b side of the frame 121, and the optical component 20 of the light-emitting device 1 is exposed from the upper surface 121a of the frame 121 through the through-hole 129. The constitution, operation, and effects other than the above in this modified example are the same as those in the third embodiment.

[0145] <Third Modified Example of the Third Embodiment>

[0146] Figure 26 It is a perspective view of the lighting device showing this modified example, and is a view observed from the first direction Z side.

[0147] Figure 27 It is a perspective view of the lighting device showing this modified example, and is a view observed from the side opposite to the first direction Z.

[0148] Figure 28 It is a side view of the lighting device showing this modified example.

[0149] Figure 29 It is a partially enlarged sectional view of the lighting device showing this modified example.

[0150] As Figures 26 to 29 shown, in the lighting device 130 of this modified example, there is provided an annular frame 131, an annular flat substrate 132, and six light-emitting devices 1. The constitution of the frame 131 is the same as the constitution of the frame 121 in the second modified example. The optical component 20 of the light-emitting device 1 is fixed to the lower surface 131b of the frame 131 and is exposed from the upper surface 131a of the frame 131 through the through-hole 139.

[0151] The flat substrate 132 is located below the frame 131 and fixed to the frame 131. When observed from the first direction Z, the outer periphery of the flat substrate 132 is disposed inside the outer periphery of the frame 131. That is, when observed from the first direction Z, the entire flat substrate 132 is hidden behind the frame 131. The upper surface 132a and the lower surface 132b of the flat substrate 132 are flat and parallel to the XY plane.

[0152] In this modified example, the substrate 40 is not provided in the light-emitting device 1, and the light source 10 is fixed to the upper surface 132a of the flat substrate 132. The optical component 20 is not fixed to the flat substrate 132 but fixed to the frame 131. Preferably, a part of the optical component 20 is in contact with the flat substrate 132. However, the optical component 20 may also be separated from the flat substrate 132. As described above, the light source 10 is fixed to the flat substrate 132, the optical component 20 is fixed to the frame 131, and the flat substrate 132 is fixed to the frame 131. Therefore, in each light-emitting device 1, the positional relationship between the light source 10 and the optical component 20 is fixed.

[0153] The upper surface 132a of the flat substrate 132 is flat, so the optical axes C of the light sources 10 are parallel to each other and parallel to the central axis C131 of the frame 131. On the other hand, the surface 131a observed from the first direction Z side of the frame 131 is inclined in the direction opposite to the first direction Z. Therefore, the main directions of the light L4 emitted from the six light-emitting devices 1 are inclined with respect to each other. The inclination angle θ of the main direction of the light L4 with respect to the optical axis C of the light source 10 is, for example, 0 degrees to 22 degrees. The light L4 emitted from each light-emitting device 1 intersects at the imaging surface 200. The configurations, operations, and effects other than those described above in this modified example are the same as those in the third embodiment.

[0154] <First Comparative Example>

[0155] Figure 30 It is an optical path diagram showing the light-emitting device of this comparative example.

[0156] As Figure 30 shown, in the light-emitting device 301 of this comparative example, the upper surface of the optical element 320 is continuously displaced upward as it separates from the optical axis C. Therefore, in the light-emitting device 1 of the first embodiment, the first region 321 of the optical element 320 corresponding to the first region 21 becomes a surface continuous with the second region 322. That is, the first region 321 is not convex, and a three-sided right-angled prism is not formed. Moreover, no metal member is provided.

[0157] In the light-emitting device 301, the light emitted from the light source 10, traveling within the optical element 320 and reaching the first region 321, is not reflected in the first region 321, but exits the optical element 320 via the first region 321. This light is stray light L301, and a part of it reaches the patient's eyes. Therefore, the patient is prone to experiencing glare. Additionally, the amount of light reaching the irradiation region 201 reduces the amount of generated stray light, resulting in low light utilization efficiency.

[0158] <Second Comparative Example>

[0159] Figure 31 It is an optical path diagram showing the light-emitting device of this comparative example.

[0160] As Figure 31 shown, in the light-emitting device 302 of this comparative example, a metal component 328 is provided in the first region 321. As a result, the stray light L301 is reduced.

[0161] However, a part of the light reflected by the metal component 328 is totally reflected in the incident region 324. Thus, the light that is incident into the optical element 320 from the incident region 324, reflected by the metal component 328, and totally reflected by the incident region 324 is reflected by the second region 322 and then reflected by the third region 323, and exits the light-emitting device 302 via the second region 322, becoming stray light L302. Since a part of the stray light L302 reaches the patient's eyes, the patient is prone to experiencing glare. Additionally, the light utilization efficiency is reduced by the amount of generated stray light.

[0162] <Third Comparative Example>

[0163] Figure 32 It is an optical path diagram showing the light-emitting device of this comparative example.

[0164] As Figure 32 shown, in the light-emitting device 303 of this comparative example, a light-shielding component 338 is provided in the first region 321. As a result, Figure 30 the shown stray light L301 is reduced. Additionally, since light is not substantially reflected in the light-shielding component 338, Figure 31 the shown stray light L302 is also reduced. However, since the light reaching the first region 321 is absorbed by the light-shielding component 338, the light utilization efficiency is low.

[0165] <Test Example>

[0166] The light-emitting devices 1 of the first embodiment, the light-emitting devices 301 of the first comparative example, the light-emitting devices 302 of the second comparative example, and the light-emitting devices 303 of the third comparative example were actually manufactured, and the same power was supplied to cause them to emit light, and the illuminance at the center of the irradiation area 201 was measured. When the center illuminance of the light-emitting device 301 was set to 100.0%, the center illuminance of the light-emitting device 302 was 109.8%, the center illuminance of the light-emitting device 303 was 95.7%, and the center illuminance of the light-emitting device 1 was 117.2%. Thus, the center illuminances of the light-emitting devices 301, 302, and 303 are lower than the center illuminance of the light-emitting device 1.

[0167] The foregoing embodiments and their modified examples are examples in which the present invention is embodied, and the present invention is not limited to these embodiments and modified examples. For example, in the foregoing embodiments and each modified example, adding, deleting, or changing several constituent elements is also included in the present invention. In addition, the foregoing embodiments and each modified example can be implemented in combination with each other.

[0168] Description of Reference Numerals

[0169] 1, 1a, 2, 2a Light-emitting device

[0170] 10 Light source

[0171] 11 Light-emitting element

[0172] 12 Sealing member

[0173] 12a Light-transmitting portion

[0174] 12b Reflecting portion

[0175] 12c Wavelength conversion portion

[0176] 20 Optical element

[0177] 21 First region

[0178] 21C Central region

[0179] 21E Outer region

[0180] 22 Second region

[0181] 23 Third region

[0182] 23a Sub-region

[0183] 23xz First section

[0184] 23yz Second section

[0185] 24 Incident region

[0186] 25 Recess

[0187] 26 Convex part

[0188] 27 Reflective member

[0189] 28 Metal part

[0190] 29 Translucent part

[0191] 31 First region

[0192] 31a Trihedral right-angle prism

[0193] 38 Metal part

[0194] 40 Substrate

[0195] 100 Lighting device

[0196] 101 Frame

[0197] 110 Lighting device

[0198] 111 Frame

[0199] 111a Upper surface

[0200] 111b Lower surface

[0201] 120 Lighting device

[0202] 121 Frame

[0203] 121a Upper surface

[0204] 121b Lower surface

[0205] 129 Through-hole part

[0206] 130 Lighting device

[0207] 131 Frame

[0208] 131a Upper surface

[0209] 131b Lower surface

[0210] 132 Flat substrate

[0211] 132a Upper surface

[0212] 132b Lower surface

[0213] 139 Through-hole part

[0214] 200 Imaging surface

[0215] 201 Irradiation area

[0216] 301, 302, 303 Light-emitting device

[0217] 320 Optical element

[0218] 321 First region

[0219] 322 Second region

[0220] 323 Third region

[0221] 324 Incident region

[0222] 328 Metal component

[0223] 338 Light-shielding component

[0224] C Optical axis

[0225] C111 Central axis of frame 111

[0226] C121 Central axis of frame 121

[0227] C131 Central axis of frame 131

[0228] D Depth of recess 25

[0229] L0 Light

[0230] L1 First light

[0231] L2 Second light

[0232] L3 Third light

[0233] L4 Fourth light

[0234] L301, L302 Stray light

[0235] Lx Length along the second direction X of irradiation region 201

[0236] Ly Length along the third direction Y of irradiation region 201

[0237] W Width of the opening of recess 25

[0238] X Second direction

[0239] Y Third direction

[0240] Z First direction

[0241] θ Inclination angle of the main direction of light L4 with respect to the optical axis C of light source 10

Claims

1. A light emitting device, characterized in that: have: a light source having a light emitting element and having an optical axis extending along a first direction; Optical components; The surface of the optical element has: an incident area for incident light emitted from the light source; a first region, which is located on the opposite side of the incident region and is larger than the light emitting element when viewed from the first direction, so that the first light entering the optical element from the incident region is reflected toward the light source, and in the first region, the first light reaching a central region overlapping with the light emitting element when viewed from the first direction in the first region and the first light reaching an outer region located outside the central region are reflected toward the light source; an annular second area, the second area surrounding the first area, and the second area reflecting second light entering the optical element from the incident area; an annular third area, the third area surrounding the incident area, the third area causing the second light reflected by the second area to be reflected toward the second area; The light reflected in the third area is emitted from the second area, The first light and the second light include light emitted from the light source and third light reflected by the light source after being reflected by the first area.

2. The light emitting device according to claim 1, characterized in that: The first region re-reflects the first light.

3. The light emitting device according to claim 1 or 2, characterized in that: The first region is a convex curved surface.

4. The light emitting device according to claim 3, characterized in that: The convex curved surface is a rotation surface having the optical axis of the light source as a rotation axis.

5. The light emitting device according to claim 1 or 2, characterized in that: The first region has a plurality of three-sided right-angle prisms.

6. The light emitting device according to claim 5, characterized in that: The plurality of three-sided right-angle prisms are arranged in a convex shape relative to the second area.

7. The light emitting device according to any one of claims 1 to 6, characterized in that: The incident region is concave, and the light source is arranged in a concave portion of the optical element defined by the incident region.

8. The light emitting device according to claim 7, characterized in that: The incident area includes a curved surface.

9. The light emitting device according to claim 7 or 8, characterized in that: In a cross section including the optical axis of the light source, a depth of the recessed portion is greater than a width of an opening of the recessed portion.

10. The light emitting device according to any one of claims 1 to 9, characterized in that: The optical element has: Light-transmitting parts; A metal member covering the light-transmitting member in the first region.

11. The light emitting device according to claim 10, characterized in that: The metal component continuously covers the first region and a portion of the second region.

12. The light emitting device according to any one of claims 1 to 9, characterized in that: The optical element has: Light-transmitting parts; A reflective member covering the light-transmitting member in the third region.

13. The light emitting device according to any one of claims 1 to 12, characterized in that: The first section in the section of the third region and the section parallel to the first section are respectively broken lines connected by a plurality of line segments, the first section has the optical axis of the light source as a first axis, and includes the first axis and a second axis orthogonal to the first axis, A second cross section and a cross section parallel to the second cross section of the cross section of the third region are respectively continuous curves, and the second cross section includes the first axis and a third axis orthogonal to the first axis and the second axis.

14. The light emitting device according to any one of claims 1 to 13, characterized in that: The light source further includes a wavelength conversion portion.

15. A lighting device, characterized in that: A light emitting device comprising at least one light emitting device according to any one of claims 1 to 14.

16. The lighting device according to claim 15, characterized in that: The lighting device is used for dental treatment.

Images