Light-emitting device

Abstract

The present invention changes an irradiation range even when the amount of change of the distance between a lens and a light source in a light irradiation direction is small.　A light-emitting device (1) comprises: a light-emitting element (10) that emits light from a light-emitting surface (11); and a lens (20) that has an incidence surface (21) on which the light emitted from the light-emitting element is incident and an emission surface (22) from which the light is emitted. The lens can move a predetermined movement distance (D) in a center direction of the luminous intensity of the light-emitting surface with respect to the light-emitting element. The incidence surface has a first region (211) that faces the center of the luminous intensity and is formed into a substantially flat surface, and a second region (212) that is provided around the first region and in which a plurality of reflection prisms (213) are formed. The ratio of the maximum width (W2) of the first region to the maximum width (W1) of the light-emitting surface is a predetermined ratio including similar ones.

Description

Light-emitting device

[0001] The present invention relates to a light emitting device.

[0002] A light-emitting device that is primarily used as a strobe in a camera device is known, which expands or reduces the lens's illumination range on an illuminated object by moving an illumination lens support in the optical axis direction (see, for example, Patent Document 1).

[0003] JP 2012-32810 A

[0004] However, when a light emitting device is installed in a mobile terminal device with a camera, it is required to reduce the height of the light emitting device, and therefore, in order to realize a wide illumination range while keeping the height low, it is required to shorten the movement distance of the illumination lens toward the center of luminous intensity (optical axis direction).

[0005] Furthermore, in a light emitting device, high light uniformity is required when the irradiation range of light is changed by moving the irradiation lens toward the center of luminous intensity.

[0006] The present invention addresses the above-mentioned problem as an example, and aims to provide a light-emitting device that enables the illumination range to be changed even when the change in the distance between the lens and the light source in the light illumination direction is small.

[0007] In order to achieve the above object, the light emitting device of the present invention comprises a light emitting element that emits light from a light emitting surface, and a lens having an incident surface into which the light emitted from the light emitting element is incident and an exit surface from which the light is emitted, wherein the lens is movable a predetermined distance in the direction of the center of luminous intensity of the light emitting surface relative to the light emitting element, the incident surface has a first region that faces the center of luminous intensity and is formed as an approximately flat surface, and a second region that is provided around the first region and in which a plurality of reflecting prisms are formed, and the ratio of the maximum width of the first region to the maximum width of the light emitting surface is a predetermined ratio that includes equality.

[0008] According to the light emitting device of the present invention, it is possible to change the illumination range even if the amount of change in the distance between the lens and the light source in the light illumination direction is small.

[0009] FIG. 1 is a side view schematically showing a configuration of a light-emitting device according to an embodiment of the present invention; FIG. 2 is a diagram showing the relationship between a simulation result of illuminance distribution and a predetermined region when the distance from the light-emitting surface of a light-emitting element of the light-emitting device according to the embodiment is a first distance; FIG. 3 is a diagram showing the relationship between a simulation result of illuminance distribution and a predetermined region when the distance from the light-emitting surface of the light-emitting element of the light-emitting device according to the embodiment is a second distance; FIG. 4 is a side view showing the positional relationship between a light-emitting element and a lens when the distance between the light-emitting surface of the light-emitting element of the light-emitting device according to the embodiment and the incident surface of the lens is minimum; FIG. 5 is a side view showing the positional relationship between a light-emitting element and a lens when the distance between the light-emitting surface of the light-emitting element of the light-emitting device according to the embodiment and the incident surface of the lens is maximum; FIG. 6 is a diagram showing the simulation result of illuminance distribution when the distance between the light-emitting surface of the light-emitting element of the light-emitting device according to the embodiment and the incident surface of the lens is minimum; FIG. 7 is a diagram showing the simulation result of illuminance distribution in the x direction when the distance between the light-emitting surface of the light-emitting element of the light-emitting device according to the embodiment and the incident surface of the lens is minimum; 1 is a diagram showing a simulation result of illuminance distribution when the distance between the light emitting surface of the light emitting element of the light emitting device and the incident surface of the lens is at a maximum. FIG. 2 is a diagram showing a simulation result of illuminance distribution in the x direction when the distance between the light emitting surface of the light emitting element of the light emitting device and the incident surface of the lens is at a maximum. FIG. 3 is a diagram showing a simulation result of illuminance distribution in the y direction when the distance between the light emitting surface of the light emitting element of the light emitting device and the incident surface of the lens is at a maximum. FIG. 4 is a graph showing the relationship between the ratio of the maximum width of the first region of the lens to the maximum width of the light emitting surface of the light emitting element of the light emitting device of the present embodiment and uniformity or illuminance. FIG. 5 is a graph showing the relationship between the ratio of the maximum width of the first region of the lens to the maximum width of the light emitting surface of the light emitting element of the light emitting device of the present embodiment and the gain of central illuminance. FIG. 6 is a side view schematically showing the configuration of a light emitting device according to a modified example of the present invention.

[0010] 1. Overview of the Embodiments First, an overview of representative embodiments of the invention disclosed in this application will be described. Note that in the following description, as an example, reference numerals in the drawings corresponding to the components of the invention are written in parentheses.

[0011] [1] A light-emitting device comprising: a light-emitting element (10) that emits light (L1, L21, L22) from a light-emitting surface (11); and a lens (20) having an incident surface (21) into which the light emitted from the light-emitting element is incident and an exit surface (22) from which the light is emitted, wherein the lens is movable a predetermined distance (D) in a direction toward the center of luminosity of the light-emitting surface relative to the light-emitting element; the incident surface has a first region (211) that faces the center of luminosity and is formed as a substantially flat surface; and a second region (212) that is provided around the first region and in which a plurality of reflecting prisms (213) are formed; and a ratio of a maximum width (W2) of the first region to a maximum width (W1) of the light-emitting surface is a predetermined ratio that includes equality.

[0012] [2] The light emitting device according to [1], wherein the ratio of the maximum width of the first region to the maximum width of the light emitting surface is 0.2 to 1.5.

[0013] [3] The light emitting device according to [1] or [2], wherein the distance between the light emitting surface and the incident surface is 0.1 to 1.0 mm.

[0014] [4] The light-emitting device according to any one of [1] to [3], wherein the first region is provided with at least one of a prism, a microlens, or a textured surface.

[0015] [5] The light emitting device according to any one of [1] to [4], wherein the angle of the inclined surface of the reflecting prism is 30° or more.

[0016] [6] The light emitting device according to any one of [1] to [5], wherein the ratio of the central illuminance of the light emitted from the lens when the distance between the light emitting surface and the incident surface is minimum to the central illuminance of the light emitted from the lens when the distance between the light emitting surface and the incident surface is maximum is 2.0 to 5.0.

[0017] [7] The light-emitting device according to any one of [1] to [6], wherein the light-emitting element is provided on an upper surface (31) of a substrate (30), and a support portion (23) protruding toward the upper surface is provided on the incident surface.

[0018] 2. Specific Examples of Embodiments A light emitting device 1 according to an embodiment of the present invention will now be described with reference to the drawings.

[0019] FIG. 1 is a side view schematically showing the configuration of a light emitting device 1 according to an embodiment of the present invention.

[0020] In the following description, for convenience, the direction of maximum luminous intensity on the light-emitting surface 11 of the light-emitting element 10 and the direction of the center of the spread of the light distribution characteristic are referred to as the optical axis A direction. The optical axis A direction is perpendicular to the light-emitting surface 11. In the optical axis A direction, the +z direction of the arrow is referred to as the upper side, and the -z direction of the arrow is referred to as the lower side. In the following description, among the directions perpendicular to the optical axis A direction, the left-right direction in Figures 1 to 5 is referred to as the x direction. In the x direction, the left side is referred to as the -x direction, and the right side is referred to as the +x direction. In the directions perpendicular to the optical axis A direction, the depth direction penetrating the paper surface in Figure 1 is referred to as the y direction. In the y direction, the front side is referred to as the -y direction, and the back side is referred to as the +y direction. In the x direction and y direction, the direction toward the center is referred to as the inward direction, and the direction away from the center is referred to as the outward direction. However, the above-mentioned directions are used for convenience of explanation, and may be defined as different directions depending on the usage situation in which the light-emitting device 1 is placed.

[0021] As shown in FIG. 1, the light emitting device 1 according to the present embodiment includes a light emitting element 10 , a lens 20 , and a substrate 30 .

[0022] The light-emitting element 10 is a semiconductor element that emits light from its light-emitting surface 11. The light-emitting element 10 is mounted on the upper surface 31 of the substrate 30 so that the optical axis A of the light-emitting surface 11 faces upward. The light-emitting element 10 is, for example, a light-emitting diode (LED). The light-emitting element 10 may be, for example, a single light-emitting diode or a chip-on-board (COB) device on which multiple LED chips are mounted. The substrate 30 is configured with a circuit that controls the current supplied to the light-emitting element 10. The shape of the light-emitting surface 11 of the light-emitting element 10 is, for example, circular or approximately circular. When the light-emitting surface 11 of the light-emitting element 10 is circular, the maximum width W1 corresponds to the diameter of the light-emitting surface 11 of the light-emitting element 10. The maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 is preferably, for example, 10% or more of the maximum width (diameter) of the lens 20. The maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 may be, for example, 0.5 to 3.0 mm. More preferably, the maximum width W1 of the light emitting surface 11 of the light emitting element 10 may be, for example, 0.8 to 3.0 mm.

[0023] Fig. 2 is a diagram showing the relationship between a simulation result of illuminance distribution and a predetermined region S when the distance from the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 is a first distance. Fig. 3 is a diagram showing the relationship between a simulation result of illuminance distribution and a predetermined region S when the distance from the light-emitting surface 11 is a second distance.

[0024] 2 and 3 show simulation results of the illuminance distribution of light irradiated from the light-emitting surface 11 at a first distance and a second distance from the light-emitting element 10, where the maximum width W1 of the light-emitting surface 11 is 1.4 mm. In FIGS. 2 and 3, the maximum width of the region S is 1.6 mm. Also, in FIGS. 2 and 3, the first distance is 0.2 mm and the second distance is 0.6 mm.

[0025] At a first distance shown in Fig. 2, 86% of the light emitted from the light-emitting surface 11 of the light-emitting element 10 enters an area S approximately equal to the area of ​​the light-emitting surface 11, and 14% of the light enters outside the area S. At a second distance shown in Fig. 3, 54% of the light emitted from the light-emitting surface 11 of the light-emitting element 10 enters an area S approximately equal to the area of ​​the light-emitting surface 11, and 46% of the light enters outside the area S.

[0026] 2 and 3, it can be seen that in the light emitting device 1, as the distance between the light emitting surface 11 of the light emitting element 10 and the incident surface 21 of the lens 20 increases, the amount of light that enters outside the region S increases compared to the light that enters the predetermined region S. In other words, according to Figures 2 and 3, when the region S is applied to the first region 211 of the lens 20, it can be seen that as the distance between the light emitting surface 11 of the light emitting element 10 and the incident surface 21 of the lens 20 increases, the amount of light that enters the region outside the first region 211 of the incident surface 21 of the lens 20 increases.

[0027] Lens 20 has an incident surface 21 onto which light emitted from light-emitting element 10 is incident, and an exit surface 22 from which the light incident from incident surface 21 exits. Lens 20 may be made of a light-transmitting resin such as polycarbonate, polyester, acrylic resin, or cyclic olefin polymer, or may be made of glass.

[0028] Fig. 4 is a side view showing the positional relationship between the light-emitting element 10 and the lens 20 when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is minimum. Fig. 5 is a side view showing the positional relationship between the light-emitting element 10 and the lens 20 when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is maximum.

[0029] As shown in FIGS. 4 and 5 , the lens 20 is configured to be movable by a predetermined movement distance D in the direction of the optical axis A relative to the light-emitting element 10 by a mechanism (not shown). The movement distance D is the difference between the maximum distance D2 and the minimum distance D1 between the light-emitting surface 11 and the incident surface 21 of the lens 20. Specifically, the distance between the light-emitting surface 11 and the incident surface 21 of the lens 20 is the shortest distance between the light-emitting surface 11 and the first region 211 of the lens 20. The mechanism for moving the lens 20 may be, for example, a cylindrical holder that holds the outer periphery of the lens 20 and can move the lens 20 in the direction of the optical axis A. The movement distance D is, for example, 0.1 to 1.0 mm. More preferably, the movement distance D is, for example, 0.4 to 1.0 mm.

[0030] The incident surface 21 of the lens 20 has a first region 211 and a second region 212. In addition, at least a reflecting prism 213 is provided in the second region 212.

[0031] The first region 211 of the incident surface 21 is the center of luminous intensity of the light-emitting surface 11 of the light-emitting element 10 and faces the center position of the light-emitting surface 11. The first region 211 is formed on a flat or substantially flat surface. The first region 211 of the incident surface 21 may be a flat surface without lens cuts, or a flat surface with lens cuts such as prisms, microlenses, or textured surfaces. If the first region 211 has lens cuts, it is preferable to provide a refractive prism with an inclination angle of 20° or less. As shown in FIGS. 4 and 5 , light beams L1 and L21, which are emitted from the light-emitting surface 11 of the light-emitting element 10 mainly in a direction centered on the optical axis A and travel substantially perpendicular to the incident surface 21 of the lens 20, are incident on the first region 211 of the incident surface 21. That is, light beams L1 and L21 near the center of luminous intensity are incident on the first region 211 of the incident surface 21. Light L1 or L21 near the center of luminous intensity is incident on first region 211 of incident surface 21, regardless of whether the distance between light-emitting surface 11 of light-emitting element 10 and incident surface 21 of lens 20 is maximum distance D2 or minimum distance D1 within the range of movement distance D. First region 211 of incident surface 21 is a region on incident surface 21 that corresponds to region S shown in FIGS.

[0032] The second region 212 of the incident surface 21 is provided on the periphery of the first region 211, that is, at a position outside in the x and y directions, which are directions perpendicular to the optical axis A. The second region 212 is a flat surface on which lens cutting has been performed, and specifically, a plurality of reflecting prisms (TIR lenses; total internal reflection lenses) 213 are formed. As shown in FIG. 5 , light L22, which is emitted from the light-emitting surface 11 of the light-emitting element 10 and travels at an angle with respect to the incident surface 21 of the lens 20, is mainly incident on the second region 212 of the incident surface 21.

[0033] In the second region 212, light L22 incident on one reflecting prism 213 is reflected by the Fresnel surface of the adjacent reflecting prism 213 on the outside, and its traveling direction changes toward the optical axis A. In other words, the reflecting prism 213 collects light L22, which travels at an angle with respect to the incident surface 21 of the lens 20, toward the optical axis A. The angle θ of the inclined surface of the reflecting prism 213 is preferably a large inclination angle, for example, equal to or greater than 30°. The second region 212 of the incident surface 21 corresponds to a region of the incident surface 21 that is outer than the region S shown in FIGS. 2 and 3 .

[0034] 2 and 3 , the ratio (W2 / W1) of the maximum width W2 of the first region 211 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 is set to a predetermined ratio including equality. In this way, in the light-emitting device 1, the light distribution of the light emitted from the light-emitting device 1 can be changed depending on the difference in the distance between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20, as described below.

[0035] Fig. 6 shows the simulation results of the illuminance distribution when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is minimum. Fig. 7 shows the simulation results of the illuminance distribution in the x direction when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is minimum. Fig. 8 shows the simulation results of the illuminance distribution in the y direction when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is minimum.

[0036] Fig. 9 is a diagram showing the simulation results of the illuminance distribution when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is at a maximum. Fig. 10 is a diagram showing the simulation results of the illuminance distribution in the x direction when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is at a maximum. Fig. 11 is a diagram showing the simulation results of the illuminance distribution in the y direction when the distance between the light-emitting surface 11 of the light-emitting element 10 of the light-emitting device 1 and the incident surface 21 of the lens 20 is at a maximum.

[0037] As shown in Figures 2 and 3, the distribution of light incident on the incident surface 21 of the lens 20 differs depending on the distance between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20. Based on this, in the light-emitting device 1, the first region 211 and the second region 212 on the incident surface 21 of the lens 20 can significantly change the distribution of light emitted from the light-emitting device 1 even if the movement distance D of the lens is short, as shown in Figures 6 to 11.

[0038] 4 , in the light emitting device 1, when the distance between the light emitting surface 11 of the light emitting element 10 and the incident surface 21 of the lens 20 is short, most of the light incident on the lens 20 passes through the first region 211 on the incident surface 21. The first region 211, which is formed on a flat or substantially flat surface, allows the incident light to pass through, thereby making it possible to make the light emitted from the lens have a wide light distribution similar to the light distribution characteristics of the light emitting element 10.

[0039] 5, in the light-emitting device 1, when the distance between the light-emitting surface 11 and the incident surface 21 of the lens 20 is greater than the state shown in Fig. 4, the light incident on the lens 20 includes not only light L21 passing through the first region 211 on the incident surface 21, but also light L22 incident on the second region 212. When the distance between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20 is increased, the light L22 incident on the increased second region 212 of the incident surface 21 is collected in the direction of the optical axis A by the reflecting prism 213, thereby improving the light collecting ability.

[0040] Fig. 12 is a graph showing the relationship between the ratio W2 / W1 of the maximum width W2 of the first region 211 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 and the uniformity U or the illuminance I in the light-emitting device 1. In Fig. 12, the uniformity U indicated by the open circles represents the uniformity of the light emitted from the lens 20 when the distance between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20 is the maximum distance D2. In Fig. 12, the illuminance I indicated by the filled circles represents the illuminance of the light emitted from the lens 20 when the distance between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20 is the minimum distance D1.

[0041] As shown in Figure 12, in the light-emitting device 1, the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10, at which both the uniformity U and the illuminance I can be achieved at high values, is found to be within a predetermined range centered on 1.

[0042] 2 and 3 , and the relationship between the illuminance distribution and the predetermined region S at a distance from the light-emitting surface 11 of the light-emitting element 10, and the relationship between the uniformity U and the illuminance I shown in FIG. 12 , the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 is set to a predetermined ratio including equality. Specifically, the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 is 0.2 to 1.5. In this way, in the light-emitting device 1, changes in the light distribution can be obtained by changing the distance between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20, as described below.

[0043] 13 is a graph showing the relationship between the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 in the light-emitting device 1 and the gain G of the central illuminance.

[0044] In the light-emitting device 1, the gain of the central illuminance is the ratio between the central illuminance of light emitted from the lens 20 when the distance between the light-emitting surface 11 and the incident surface 21 of the lens 20 is the minimum distance D1, and the central illuminance of light emitted from the lens 20 when the distance between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20 is the maximum distance D2. As shown in Fig. 13, when the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 is in the above-mentioned range of 0.2 to 1.5, the gain G of the central illuminance is a value in the range of approximately 2.0 to 5.0.

[0045] In the light-emitting device 1 configured as described above, the lens 20 is capable of moving a predetermined distance D in the direction of the optical axis A, which is the direction of the center of luminous intensity of the light-emitting surface 11 of the light-emitting element 10, relative to the light-emitting element 10, and the incident surface 21 of the lens 20 has a first region 211 formed as an approximately flat surface facing the center of luminous intensity of the light-emitting surface 11 of the light-emitting element 10, and a second region 212 provided around the first region 211 and in which a plurality of reflecting prisms 213 are formed, and the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light-emitting surface 11 of the light-emitting element 10 is a predetermined ratio that includes equality.

[0046] Specifically, for example, the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light emitting surface 11 of the light emitting element 10 may be 0.2 to 1.5.

[0047] The distance between the light emitting surface 11 of the light emitting element 10 and the incident surface 21 of the lens 20, which changes as the lens 20 moves, may be specifically 0.1 to 1.0 mm.

[0048] By doing so, in the light emitting device 1, the difference in the distance between the light emitting surface 11 of the light emitting element 10 and the incident surface 21 of the lens 20 changes the light distribution of the light incident on the first region 211 of the incident surface 21 and the light incident on the second region 212 of the incident surface 21, thereby obtaining a change in the light distribution of the light emitted from the light emitting device 1. Furthermore, the light emitted from the light emitting device 1 can achieve both high uniformity and high illuminance.

[0049] The first region of the light-emitting surface 11 may be provided with at least one of a prism, a microlens, and a textured surface.

[0050] By doing so, it is possible to adjust the uniformity and / or illuminance of the light emitted from the light emitting device 1. It is also possible to improve the appearance of the light emitting device 1 when viewed from the light exit surface 22 side of the lens 20. Specifically, the transmission of external light is reduced, reducing the visibility of the light emitting element 10 seen through the lens 20, thereby improving the appearance.

[0051] The ratio between the central illuminance of the light emitted from the lens 20 when the distance D between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20 is the minimum distance D1 and the central illuminance of the light emitted from the lens 20 when the distance D between the light-emitting surface 11 of the light-emitting element 10 and the incident surface 21 of the lens 20 is the maximum distance D2 may be 2.0 to 5.0.

[0052] By doing so, it is possible to obtain a change in the central illuminance of the light emitted from the light-emitting device 1 according to the distance D. Furthermore, for example, when the light-emitting device 1 is mounted on a camera, by changing the distance D, it is possible to set the illuminance during telephoto shooting to a higher value than the illuminance during close-up shooting.

[0053] Therefore, according to the light emitting device 1, it is possible to change the irradiation range even if the amount of change in the distance between the lens 20 and the light emitting element 10 in the light irradiation direction is small.

[0054] FIG. 14 is a side view schematically showing the configuration of a light emitting device 1B according to a modified example of the present invention.

[0055] As shown in FIG. 14 , light-emitting device 1B differs from the previously described light-emitting device 1 in that support portions 23 are provided on the incident surface 21 of lens 20B, protruding downward in the optical axis A direction toward the upper surface 31 of substrate 30 on which light-emitting element 10 is provided. By providing support portions 23 on lens 20B, light-emitting device 1B can set a minimum distance D1 between light-emitting surface 11 of light-emitting element 10 and incident surface 21 of lens 20. Furthermore, when the distance between light-emitting surface 11 of light-emitting element 10 and incident surface 21 of lens 20 is minimum distance D1, both ends (outer peripheries) of lens 20 can be supported relative to substrate 30, thereby maintaining a constant tilt of lens 20. Therefore, light-emitting device 1B can achieve more stable optical performance.

[0056] In addition, those skilled in the art can appropriately modify the present invention in accordance with conventionally known knowledge. As long as such modifications still comprise the structure of the present invention, they are of course included in the scope of the present invention.

[0057] For example, in the light emitting device 1, the dimensions of the maximum width W1 of the light emitting element 10 and the light emitting surface 11, and the dimensions of the maximum width W2 of the first region 211 of the lens 20 and the incident surface 21 are not limited to the above-mentioned examples. In other words, in the light emitting device 1, the ratio W2 / W1 of the maximum width W2 of the first region 211 of the lens 20 to the maximum width W1 of the light emitting surface 11 of the light emitting element 10 is within the above-mentioned range, and the movement distance D of the lens 20 is set according to each dimension, whereby the above-mentioned effects can be achieved.

[0058] For example, in the light emitting devices 1 and 1B, the lenses 20 and 20B are movable, but the present invention is not limited to this. The light emitting device may be one in which the light emitting element 10 is movable relative to a fixed lens.

[0059] 1, 1B...light emitting device, 10...light emitting element, 11...light emitting surface, 20, 20B...lens, 21...incident surface, 22...exit surface, 23...support portion, 30...substrate, 31...upper surface, 211...first region, 212...second region, 213...reflecting prism, A...optical axis, D...movement distance, D1...minimum distance (distance), D2...maximum distance (distance), G...gain, I...illuminance, L1, L21, L22...light, S...region, U...uniformity, W1...maximum width of light emitting surface, W2...maximum width of first region, θ...angle

Claims

1. A light-emitting device comprising: a light-emitting element that emits light from a light-emitting surface; and a lens having an entrance surface into which the light emitted from the light-emitting element is incident and an exit surface from which the light is emitted, wherein the lens is movable a predetermined distance in a direction toward the center of luminosity of the light-emitting surface relative to the light-emitting element, the entrance surface having a first region formed on a substantially flat surface facing the center of luminosity, and a second region provided around the first region and in which a plurality of reflecting prisms are formed, and wherein the ratio of the maximum width of the first region to the maximum width of the light-emitting surface is a predetermined ratio including equality.

2. The light emitting device according to claim 1, wherein the ratio of the maximum width of said first region to the maximum width of said light emitting surface is 0.2 to 1.

5.

3. The light emitting device according to claim 1 or 2, wherein the distance between the light emitting surface and the incident surface is 0.1 to 1.0 mm.

4. The light emitting device according to claim 1, wherein the first region is provided with at least one of a prism, a microlens, or a textured surface.

5. The light emitting device according to claim 1, wherein the angle of the inclined surface of the reflecting prism is 30° or more.

6. The light emitting device according to claim 1, wherein the ratio of the central illuminance of the light emitted from the lens when the distance between the light emitting surface and the incident surface is minimum to the central illuminance of the light emitted from the lens when the distance between the light emitting surface and the incident surface is maximum is 2.0 to 5.

0.

7. The light emitting device according to claim 1, wherein the light emitting element is provided on an upper surface of a substrate, and a support portion is provided on the incident surface, the support portion protruding toward the upper surface.

Images