JP7839958B2 - Light-emitting module - Google Patents

Description

This invention relates to a light-emitting module.

For example, Patent Document 1 discloses a light-emitting device having a configuration in which a member containing a light-reflective or light-scattering filler is placed between a first light-emitting diode and a second light-emitting diode arranged on a substrate.

U.S. Patent Application Publication No. 2018/0259137

The present invention aims to provide a highly reliable light-emitting module.

According to one aspect of the present invention, the light-emitting module comprises a substrate, a first light source disposed on the substrate, the first light source having a first light-emitting element, a first light-transmitting member covering the side surface of the first light-emitting element, and a first light-reflecting member covering the lower surface of the first light-transmitting member, a second light source disposed on the substrate, the second light source having a second light-emitting element, a second light-transmitting member covering the side surface of the second light-emitting element, and a second light-reflecting member covering the lower surface of the second light-transmitting member, and a light-shielding member in contact with the side surface of the first light-transmitting member, the side surface of the first light-reflecting member, the lower surface of the first light-reflecting member, the side surface of the second light-transmitting member, the side surface of the second light-reflecting member, the lower surface of the second light-reflecting member, and the upper surface of the substrate.

According to the present invention, a highly reliable light-emitting module can be provided.

This is a schematic plan view of the light-emitting module of the first embodiment. This is a schematic cross-sectional view along line II-II in Figure 1. This is an enlarged cross-sectional view of section A in Figure 2. This is a schematic plan view of the light-emitting module of the second embodiment. Figure 4 is a schematic cross-sectional view along the line V-V. This is a schematic plan view of the light-emitting module of the third embodiment. This is a schematic plan view of a first modified example of the light source in the light-emitting module of the embodiment. Figure 7 is a schematic cross-sectional view along the line VIII-VIII. This is a schematic cross-sectional view of a second modified example of the light source in the light-emitting module of the embodiment.

The following description of the light-emitting module of the embodiment will be based on the drawings. The dimensions, materials, shapes, and relative arrangements of the components described in the embodiment are merely illustrative examples and not intended to be limiting unless otherwise specified. Note that the size and positional relationships of the components shown in each drawing may be exaggerated for clarity. Furthermore, in the following description, the same name and reference numeral indicate the same or identical components, and detailed explanations will be omitted as appropriate. In some cases, end views showing only the cross-section will be shown as cross-sectional views.

In the following description, terms indicating specific directions or positions (e.g., "up," "down," and other terms including these) may be used. However, these terms are used merely for clarity to indicate the relative directions or positions in the referenced drawings. If the relative directional or positional relationships expressed by terms such as "up" and "down" in the referenced drawings are the same, the arrangement in drawings other than those disclosed, actual products, etc., does not necessarily have to be identical to those in the referenced drawings. In this specification, the positional relationship expressed as "up (or down)" includes, for example, the case where two members are in contact, and the case where the two members are not in contact, but one member is located above (or below) the other member.

In the diagrams shown below, directions may be indicated by the X, Y, and Z axes. The X direction, along the X-axis, indicates a predetermined direction within the light-emitting surface of the light-emitting module of the embodiment. The Y direction, along the Y-axis, indicates a direction perpendicular to the X direction within the light-emitting surface. The Z direction, along the Z-axis, indicates a direction perpendicular to the light-emitting surface. That is, the light-emitting surface of the light-emitting module is parallel to the XY plane, and the Z-axis is perpendicular to the XY plane. For example, in the following embodiment, the first direction is described as the direction along the X-axis, the second direction as the direction along the Y-axis, and the third direction as the direction along the Z-axis. The first direction may also be described as the lateral direction. Note that the first, second, and third directions do not necessarily have to be along the X, Y, and Z axes, respectively.

[First Embodiment]
As shown in Figure 1, the light-emitting module 1 of the first embodiment comprises a substrate 50 and two or more light sources 10 arranged on the substrate 50.

<Circuit board>
The substrate 50 is a wiring board having wiring sections for supplying power to the light source 10. To make the light-emitting module 1 thinner, the substrate 50 is preferably a flexible substrate. However, the substrate 50 may also be a rigid substrate.

As shown in Figure 2, the substrate 50 has an insulating member 51 and a conductive wiring section 52. The wiring section 52 is, for example, located on the upper surface 50c of the substrate 50. For example, the upper surface of the insulating member 51 constitutes the upper surface 50c of the substrate 50, and the lower surface of the insulating member 51 constitutes the lower surface 50d of the substrate 50. The lower surface 50d is located on the opposite side of the upper surface 50c in the third direction Z. The wiring section 52 may also be located on the lower surface 50d of the substrate 50. Furthermore, the substrate 50 is not limited to a single-layer wiring structure, but may also be a multilayer wiring structure having two or more wiring sections. In the case of a multilayer wiring structure, the wiring section may be located inside the substrate 50.

<Light source>
Two or more light sources 10 include at least two adjacent light sources 10A and 10B in the first direction X. If the light-emitting module 1 includes three or more light sources 10, one of the two adjacent light sources in the first direction X is designated as the first light source 10A and the other as the second light source 10B. Note that the first light source 10A, the second light source 10B, and light sources other than the first light source 10A and the second light source 10B may be referred to simply as light sources 10 without distinction.

Furthermore, in the following explanation, each component of the first light source 10A will be prefixed with "1st," and the letter "A" will be added to the end of the code representing each component of the first light source 10A. Each component of the second light source 10B will be prefixed with "2nd," and the letter "B" will be added to the end of the code representing each component of the second light source 10B. Note that in some cases, components of the first light source 10A and the second light source 10B may not be distinguished (without prefixing "1st" or "2nd"). Components represented without prefixing "1st" or "2nd" represent components of each light source 10 provided in the light-emitting module 1.

Each light source 10 has the same configuration. Furthermore, multiple light sources 10 with optical characteristics (brightness, chromaticity, etc.) within a predetermined range are selected and arranged on the substrate 50. This reduces brightness and chromaticity unevenness in the light-emitting module 1.

(Light-emitting element)
Each light source 10 has a light-emitting element 11. The first light source 10A has a first light-emitting element 11A, and the second light source 10B has a second light-emitting element 11B.

Each light source 10 has, for example, one light-emitting element 11. The light-emitting element 11 includes a semiconductor structure. The semiconductor structure includes, for example, an element substrate such as sapphire or gallium nitride, an n-type semiconductor layer disposed on the element substrate, a p-type semiconductor layer, and a light-emitting layer located between the n-type semiconductor layer and the p-type semiconductor layer. The light-emitting element 11 also includes an n-side electrode electrically connected to the n-type semiconductor layer and a p-side electrode electrically connected to the p-type semiconductor layer. Furthermore, each light source 10 includes at least two electrodes 17 disposed on the lower surface side of the light-emitting element 11. One of the two electrodes 17 is electrically connected to the p-side electrode of the light-emitting element 11, and the other is electrically connected to the n-side electrode of the light-emitting element 11. Note that each light source 10 does not necessarily include electrodes 17. If each light source 10 does not include electrodes 17, the n-side electrode and p-side electrode of the light-emitting element 11 constitute a part of the lower surface of each light source 10. Also, each light source 10 does not necessarily have a substrate. This makes it easier to miniaturize each light source 10 in the third direction (Z direction).

The structure of the light-emitting layer may be a double heterostructure, a single quantum well (SQW) structure with a single active layer, or a multiple quantum well (MQW) structure with a group of active layers. The light-emitting layer is capable of emitting visible light or ultraviolet light. As visible light, the light-emitting layer is capable of emitting from blue to red. Examples of semiconductor structures containing such a light-emitting layer include In _x Al _y Ga _1-x-y N (0 ≤ x, 0 ≤ y, x + y ≤ 1). The semiconductor structure may contain at least one light-emitting layer capable of the above-described emission. For example, the semiconductor structure may have one or more light-emitting layers between an n-type semiconductor layer and a p-type semiconductor layer, or it may have a structure in which an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer are sequentially repeated multiple times. When the semiconductor structure contains multiple light-emitting layers, it may include light-emitting layers with different emission peak wavelengths, or it may include light-emitting layers with the same emission peak wavelength. Note that "the same emission peak wavelength" means that there may be a variation of, for example, a few nanometers. Such combinations of light-emitting layers can be selected as appropriate. For example, if a semiconductor structure contains two light-emitting layers, the light-emitting layers can be selected in combinations such as blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and red light, or green light and red light. Furthermore, the light-emitting layer may contain multiple active layers with different emission peak wavelengths, or it may contain multiple active layers with the same emission peak wavelength.

A single light source 10 may have two or more light-emitting elements 11. The emission peak wavelengths of the multiple light-emitting elements 11 included in each light source 10 may be the same or different. For example, if each light source 10 includes two light-emitting elements, the emission peak wavelengths of the light-emitting elements 11 can be selected from combinations such as blue light and green light, blue light and red light, ultraviolet light and blue light, ultraviolet light and green light, ultraviolet light and red light, or green light and red light. For example, if each light source 10 includes three light-emitting elements 11, the emission peak wavelengths of the light-emitting elements 11 can be selected from combinations such as blue light, green light and red light, ultraviolet light, green light and red light, ultraviolet light, blue light and green light, ultraviolet light, blue light and red light, or ultraviolet light, green light and red light.

(Translucent member)
Each light source 10 further comprises a light-transmitting member 12. The first light source 10A further comprises a first light-transmitting member 12A, and the second light source 10B further comprises a second light-transmitting member 12B.

The translucent member 12 covers the side surface of the light-emitting element 11. The translucent member 12 also covers the upper surface of the light-emitting element 11. The translucent member 12 has the function of protecting the light-emitting element 11. The translucent member 12 is transparent to the light emitted by the light-emitting element 11. The transmittance of the translucent member 12 with respect to the emission peak wavelength of the light-emitting element 11 is preferably 50% or more, and more preferably 70% or more.

The area of the upper surface 12d of the translucent member 12 is larger than the area of the upper surface of the light-emitting element 11. The upper surface 12d of the translucent member 12 is located above the upper surface of the light-emitting element 11. The upper surface 12d of the translucent member 12 functions as the light-emitting surface of the light-emitting module 1.

(Light-reflective material)
Each light source 10 further comprises a light-reflecting member 13. The first light source 10A further comprises a first light-reflecting member 13A, and the second light source 10B further comprises a second light-reflecting member 13B.

The light-reflecting member 13 has reflectivity to the light emitted by the light-emitting element 11. The reflectance of the light-reflecting member 13 with respect to the emission peak wavelength of the light-emitting element 11 is preferably 60% or more, and more preferably 80% or more.

The light-reflective member 13 covers the lower surface 12f of the light-transmitting member 12 and the lower surface of the light-emitting element 11. The lower surface 12f of the light-transmitting member 12 and the lower surface of the light-emitting element 11 face the upper surface 50c of the substrate 50. The light-reflective member 13 also covers the sides of the electrodes 17 of the light source 10. The lower surface of the electrodes 17 is exposed from the light-reflective member 13.

Light guided through the translucent member 12 and directed toward the lower surface 12f of the translucent member 12 is reflected toward the upper surface 12d of the translucent member 12 by the light-reflecting member 13. This improves the brightness of the light extracted from the upper surface 12d of the translucent member 12. Furthermore, light emitted from the light-emitting element 11 downwards is reflected toward the upper surface 12d of the translucent member 12 by the light-reflecting member 13, improving the brightness of the light extracted from the upper surface 12d of the translucent member 12.

<Light-shielding material>
The light-emitting module 1 further includes a light-shielding member 30. The light-shielding member 30 is positioned between the first light source 10A and the second light source 10B, which are adjacent in the first direction X. The light-shielding member 30 has light-shielding properties against the light emitted by the light-emitting element 11. The transmittance of the light-shielding member 30 with respect to the emission peak wavelength of the light-emitting element 11 is preferably 40% or less, and more preferably 20% or less. For example, a resin member or a metal member can be used as the light-shielding member 30.

The first light source 10A and the second light source 10B can be controlled individually. By placing a light-shielding member 30 between the first light source 10A and the second light source 10B, when one of the light sources is emitting light and the other is not, the propagation of light from the emitting light source to the non-emitting light source can be reduced. This makes it easier to improve the contrast ratio between the brightness near the emitting light source and the brightness near the non-emitting light source.

As shown in Figure 3, the light-shielding member 30 is in contact with the side surface 12e of the first light-transmitting member 12A of the first light source 10A, the side surface 13e of the first light-reflecting member 13A of the first light source 10A, the side surface 12e of the second light-transmitting member 12B of the second light source 10B, and the side surface 13e of the second light-reflecting member 13B of the second light source 10B.

Furthermore, the light-shielding member 30 is also positioned between a portion of the lower surface 13d of the first light-reflecting member 13A, which constitutes the lower surface of the first light source 10A, and the upper surface 50c of the substrate 50, and between a portion of the lower surface 13d of the second light-reflecting member 13B, which constitutes the lower surface of the second light source 10B, and the upper surface 50c of the substrate 50. The light-shielding member 30 is in contact with the lower surface 13d of the first light-reflecting member 13A, the lower surface 13d of the second light-reflecting member 13B, and the upper surface 50c of the substrate 50. This improves the adhesion between the light-shielding member 30 and the first light source 10A, and between the light-shielding member 30 and the second light source 10B. Therefore, the likelihood of the light-shielding member 30 peeling off from the first light source 10A and from the second light source 10B can be reduced, thereby increasing the reliability of the light-emitting module 1.

As shown in Figure 3, it is preferable that the light-shielding member 30 contacts the corner between the side surface (side surface 13e of the light-reflecting member 13) and the bottom surface (bottom surface 13d of the light-reflecting member 13) of the light source 10. This improves the adhesion between the light-shielding member 30 and the first light source 10A, and between the light-shielding member 30 and the second light source 10B.

The light-shielding member 30 may absorb or reflect the light emitted by the light-emitting element 11. Preferably, the light-shielding member 30 has reflectivity to the light emitted by the light-emitting element 11. The reflectivity of the light-shielding member 30 with respect to the emission peak wavelength of the light-emitting element 11 is preferably 60% or more, and more preferably 80% or more. As the light-reflecting light-shielding member 30, for example, a resin member or metal member containing light-scattering particles can be used.

Because the light-shielding member 30 has light-reflecting properties, the light that propagates from the light-emitting element 11 through the light-transmitting member 12 and is directed toward the side surface 12e of the light-transmitting member 12 is reflected by the light-shielding member 30 toward the upper surface 12d of the light-transmitting member 12, thereby improving the brightness of the light extracted from the upper surface 12d of the light-transmitting member 12.

Because the light-shielding member 30 has light-reflecting properties, it becomes easier to improve the brightness near the light-shielding member 30 compared to when the light-shielding member 30 absorbs light from the light-emitting element 11. This improves the light extraction efficiency of the light-emitting module 1.

To improve the brightness from the upper surface 12d of the first light-transmitting member 12A, it is preferable that the entire upper surface 12d of the first light-transmitting member 12A is exposed from the light-shielding member 30. Similarly, to improve the brightness from the upper surface 12d of the second light-transmitting member 12B, it is preferable that the entire upper surface 12d of the second light-transmitting member 12B is exposed from the light-shielding member 30.

Furthermore, the light-shielding member 30 may cover a portion of the upper surface 12d near the side surface 12e of the light-transmitting member 12. In this case, the contact area between the light-shielding member 30 and the light-transmitting member 12 increases, improving the adhesion between the light-shielding member 30 and the light-transmitting member 12.

In a state where both the first light source 10A and the second light source 10B are emitting light, it is preferable that a portion of the side surface 12e of the first light-transmitting member 12A is exposed from the light-shielding member 30 in order to reduce the decrease in brightness in the region between the first light source 10A and the second light source 10B. Similarly, it is preferable that a portion of the side surface 12e of the second light-transmitting member 12B is exposed from the light-shielding member 30 in order to reduce the decrease in brightness in the region between the first light source 10A and the second light source 10B. In the example shown in Figure 3, a portion 12e1 on the upper surface 12d side of the side surface 12e of the first light-transmitting member 12A and a portion 12e1 on the upper surface 12d side of the side surface 12e of the second light-transmitting member 12B are exposed from the light-shielding member 30. This reduces the blocking of light emitted from a portion 12e1 on the upper surface 12d side of the side 12e of the first light-transmitting member 12A, and light emitted from a portion 12e1 on the upper surface 12d side of the side 12e of the second light-transmitting member 12B, by the light-shielding member 30. Therefore, the decrease in brightness in the region between the first light source 10A and the second light source 10B can be reduced.

To reduce the propagation of light from the first light-emitting element 11A to the second light-emitting element 11B in a non-emitting state, it is preferable that at least a portion of the upper surface 31 of the light-shielding member 30 is located above the upper surface of the first light-emitting element 11A. In the example shown in Figure 2, the upper surface 31 of the light-shielding member 30 is, for example, concave, and the position of at least a portion of its upper surface 31 in the third direction Z is higher than the position of the upper surface of the first light-emitting element 11A in the third direction Z.

To reduce the propagation of light from the second light-emitting element 11B in an emitting state to the first light-emitting element 11A in a non-emitting state, it is preferable that at least a portion of the upper surface 31 of the light-shielding member 30 is located above the upper surface of the second light-emitting element 11B. The position of at least a portion of the upper surface 31 of the light-shielding member 30, for example, a concave surface, in the third direction Z is higher than the position of the upper surface of the second light-emitting element 11B in the third direction Z.

By making the upper surface 31 of the light-shielding member 30 concave, a portion 32 is formed in which the light-shielding member 30 is thinner in the lateral direction, as shown in Figure 3. Light guided through the light-transmitting member 12 is more easily extracted from the side surface 12e of the light-transmitting member 12, through the thinned portion 32 of the light-shielding member 30, and upward to the light-shielding member 30. This makes it easier to adjust the brightness of the region between the first light source 10A and the second light source 10B. For example, the brightness of the region between the first light source 10A and the second light source 10B can be adjusted by changing the lateral thickness of the portion 32 that is thinner in the lateral direction. In addition, by making the upper surface 31 of the light-shielding member 30 concave, it becomes easier to increase the contact area between the side surface 12e of the light-transmitting member 12 and the light-shielding member 30 compared to when the upper surface 31 of the light-shielding member 30 is convex. This improves the adhesion between the light-shielding member 30 and the first light source 10A, and/or the adhesion between the light-shielding member 30 and the second light source 10B. The concave surface may be composed of a curved surface or a flat surface. Furthermore, the concave surface may be composed of a combination of a curved surface and a flat surface. The upper end of the portion 32 where the lateral thickness of the light-shielding member 30 is reduced, which is in contact with the side surface 12e of the first light-transmitting member 12A, may be at the same height as the upper end of the portion 32 where the lateral thickness of the light-shielding member 30 is reduced, which is in contact with the side surface 12e of the second light-transmitting member 12B, or it may be at a different height. The upper surface 31 of the light-shielding member 30 may be a flat surface perpendicular to the third direction Z, or it may be a convex surface.

The light-emitting module 1 further includes a conductive member 40 that electrically connects each light source 10 to the substrate 50. For example, solder can be used as the material for the conductive member 40. The conductive member 40 is positioned between the electrode 17 of the light source 10 and the wiring portion 52 of the substrate 50, and is joined to the electrode 17 and the wiring portion 52.

The conductive member 40 includes a first conductive member 40A that electrically connects the first light source 10A and the substrate 50, and a second conductive member 40B that electrically connects the second light source 10B and the substrate 50. The first conductive member 40A is positioned between the electrode 17 of the first light source 10A and the wiring portion 52 of the substrate 50, and is joined to the electrode 17 of the first light source 10A and the wiring portion 52. The second conductive member 40B is positioned between the electrode 17 of the second light source 10B and the wiring portion 52 of the substrate 50, and is joined to the electrode 17 of the second light source 10B and the wiring portion 52.

A gap 60 is formed between the lower surface 13d of the light-reflecting member 13, which is the lower surface of the light source 10, and the upper surface 50c of the substrate 50. The thickness of the gap 60 in the third direction Z is the sum of the thickness of the conductive member 40 and the thickness of the wiring portion 52 in the third direction Z. A gap 60 is located between the first conductive member 40A and the light-shielding member 30 in contact with the lower surface 13d of the first light-reflecting member 13A, and between the second conductive member 40B and the light-shielding member 30 in contact with the lower surface 13d of the second light-reflecting member 13B. The gap 60 reduces the amount of thermal stress from the light-shielding member 30 applied to the first conductive member 40A and the second conductive member 40B, thereby reducing the likelihood of cracks or other damage to the first conductive member 40A and the second conductive member 40B. This increases the reliability of the light-emitting module 1.

Furthermore, the conductive member 40 is not limited to being directly bonded to the electrode 17 of the light source 10. Alternatively, a metal film covering the lower surface of the electrode 17 and the lower surface 13d of the light-reflecting member 13 may be placed on the lower surface of the light source 10, and the conductive member 40 may be bonded to this metal film.

According to the first embodiment, each light source 10 further includes a light-adjusting member 15 that covers the upper surface of the light-emitting element 11. The first light source 10A further includes a first light-adjusting member 15A that covers the upper surface of the first light-emitting element 11A. The second light source 10B further includes a second light-adjusting member 15B that covers the upper surface of the second light-emitting element 11B. The first light-transmitting member 12A covers the upper surface of the first light source 10A via the first light-adjusting member 15A. The second light-transmitting member 12B covers the upper surface of the second light source 10B via the second light-adjusting member 15B.

The light adjustment member 15 controls the amount and direction of light emitted from the upper surface of the light-emitting element 11. The light adjustment member 15 has both reflectivity and transmittance to the light emitted by the light-emitting element 11. A portion of the light emitted from the upper surface of the light-emitting element 11 is reflected by the light adjustment member 15, while another portion is transmitted through the light adjustment member 15. The transmittance of the light adjustment member 15 with respect to the emission peak wavelength of the light-emitting element 11 is preferably, for example, 1% to 50%, and more preferably 3% to 30%. The light adjustment member 15 reduces the brightness directly above the light-emitting element 11, thereby reducing brightness unevenness in the light-emitting module 1.

In the example shown in Figure 1, the light-emitting module 1 comprises three or more light sources 10 arranged on the substrate 50. Specifically, in addition to the first light source 10A and the second light source 10B, which are positioned adjacent to each other in the first direction X, the light-emitting module 1 further comprises a third light source 10C. The third light source 10C has the same configuration as the first light source 10A and the second light source 10B and is joined to the wiring portion 52 of the substrate 50 via the aforementioned conductive member 40. While Figure 1 illustrates nine light sources 10, the number of light sources 10 is not limited to this.

The first light source 10A and the third light source 10C are positioned adjacent to each other in the second direction Y, which is perpendicular to the first direction X. Of the three or more light sources 10, the two light sources positioned adjacent to each other in the first direction X are designated as the first light source 10A and the second light source 10B, and the light source positioned adjacent to the first light source 10A in the second direction Y is designated as the third light source 10C. In Figure 1, for convenience, the light source in the lower left is designated as the first light source 10A, the light source to the right of the first light source 10A is designated as the second light source 10B, and the light source above the first light source 10A is designated as the third light source 10C. The first light source 10A, the second light source 10B, and the third light source 10C are not limited to the three light sources labeled 10A, 10B, and 10C in Figure 1, but represent any three light sources among the three or more light sources that satisfy the above arrangement relationship.

A light-shielding member 30 is also positioned between the first light source 10A and the third light source 10C. The light-shielding member 30 is in contact with the side surface 12e of the first light-transmitting member 12A, the side surface 13e of the first light-reflecting member 13A, the lower surface 13d of the first light-reflecting member 13A, the side surface of the light-transmitting member 12 of the third light source 10C, the side surface of the light-reflecting member 13 of the third light source 10C, the lower surface of the light-reflecting member 13 of the third light source 10C, and the upper surface 50c of the substrate 50. Therefore, the adhesion between the light-shielding member 30 and the first light source 10A, and the adhesion between the light-shielding member 30 and the third light source 10C are improved.

The brightness above the light-shielding member 30 between each light source 10 tends to be lower than the brightness above the light source 10. Therefore, variations in the distance between each light source 10 affect brightness unevenness on the light-emitting surface of the light-emitting module 1. According to this embodiment, the shortest distance dX in the first direction X between the first light source 10A and the second light source 10B, and the shortest distance dY in the second direction Y between the first light source 10A and the third light source 10C, are within the range of accuracy variations of the device that arranges the light sources 10 on the substrate 50. For example, the shortest distance dX between the first light source 10A and the second light source 10B in the first direction X is between 0.9 and 1.1 times the shortest distance dY between the first light source 10A and the third light source 10C in the second direction Y. This reduces brightness unevenness on the light-emitting surface of the light-emitting module 1.

The following are examples of the specific materials used for the aforementioned components.

Resin or ceramic can be used as the material for the insulating member 51 of the substrate 50. For example, polyimide can be used as the resin for the insulating member 51. For example, a metal such as copper can be used as the material for the wiring portion 52 of the substrate 50.

As the material for the light-transmitting member 12, for example, light-transmitting resins such as epoxy resin, modified epoxy resin, silicone resin, modified silicone resin, acrylate resin, urethane resin, and fluororesin can be used. Among these, silicone resin and modified silicone resin are preferred because they have excellent heat resistance and light resistance. For example, phenyl silicone resin or dimethyl silicone resin can be used as the material for the light-transmitting member 12.

As the light-reflecting member 13, for example, a resin member containing gases such as nitrogen or oxygen, or a resin member containing light-scattering particles can be used. As the light-scattering particles of the light-reflecting member 13, for example, particles of titania, silica, alumina, zinc oxide, magnesium oxide, zirconia, yttria, calcium fluoride, magnesium fluoride, niobium pentoxide, barium titanate, tantalum pentoxide, barium sulfate, or glass can be used. As the resin material of the light-reflecting member 13, the same translucent resin listed as the resin material for the translucent member 12 can be used. Note that the light-reflecting member 13 may contain both gases and light-scattering particles.

If the light-shielding member 30 has light reflectivity, the same light-transmitting resin as that listed for the light-transmitting member 12 can be used as the resin material for the light-shielding member 30. The same particles as those listed for the light-scattering particles of the light-reflective member 13 can be used as the light-scattering particles of the light-shielding member 30.

As the light-adjusting member 15, for example, a resin member containing light-scattering particles can be used. The same particles as those listed for the light-reflecting member 13 can be used as the light-scattering particles of the light-adjusting member 15. The same translucent resin as those listed for the translucent member 12 can be used as the resin material of the light-adjusting member 15. Furthermore, the light-adjusting member 15 may be, for example, a metal member such as Al or Ag, or a dielectric multilayer film.

[Second Embodiment]
Next, the light-emitting module 2 of the second embodiment will be described with reference to Figures 4 and 5. In the light-emitting module 2 of the second embodiment, the configuration of the light source 10 differs from that of the light-emitting module 1 of the first embodiment.

Each light source 10 of the light-emitting module 2 has a sealing member 14 located between the light-emitting element 11 and the light-transmitting member 12 in a plan view. The first light source 10A has a first sealing member 14A located between the first light-emitting element 11A and the first light-transmitting member 12A in a plan view. The second light source 10B has a second sealing member 14B located between the second light-emitting element 11B and the second light-transmitting member 12B in a plan view.

The sealing member 14 covers the top and sides of the light-emitting element 11, protecting it. The sealing member 14 is translucent to the light emitted by the light-emitting element 11. The transmittance of the sealing member 14 with respect to the emission peak wavelength of the light-emitting element 11 is preferably 50% or more, and more preferably 70% or more. The same translucent resin as that used for the translucent member 12 can be used as the material for the sealing member 14.

The translucent member 12 covers the top and side surfaces of the sealing member 14. The side surfaces of the sealing member 14 are in contact with the translucent member 12. Preferably, the difference between the refractive index of the resin material of the sealing member 14 and the refractive index of the resin material of the translucent member 12 is within ±0.05. This reduces light refraction at the interface between the side surfaces of the sealing member 14 and the translucent member 12, making it easier to spread light laterally. This reduces brightness unevenness on the light-emitting surface of the light-emitting module 2. Note that the refractive index of each member is the refractive index at the emission peak wavelength of the light source 10.

The difference between the linear thermal expansion coefficients of the resin material of the sealing member 14 and the resin material of the light-transmitting member 12 is preferably within ±30 ppm/°C. This makes it difficult for the light-transmitting member 12 to peel off from the sealing member 14. This increases the reliability of the light-emitting module 2. A phenyl silicone resin with a refractive index of approximately 1.5 may be used as the resin material for both the sealing member 14 and the light-transmitting member 12.

The first light-reflective member 13A covers the lower surface of the first sealing member 14A, and the second light-reflective member 13B covers the lower surface of the second sealing member 14B. As a result, light directed towards the lower surface of the sealing member 14 is reflected by the light-reflective member 13 towards the upper surface 12d of the light-transmitting member 12, thereby improving the brightness of the light extracted from the upper surface 12d of the light-transmitting member 12.

In the light-emitting module 2, the aforementioned light-adjusting member 15 is positioned on the upper surface of the sealing member 14. The first light-adjusting member 15A is positioned on the upper surface of the first sealing member 14A, and the first light-transmitting member 12A covers the upper surface of the first sealing member 14A via the first light-adjusting member 15A. The second light-adjusting member 15B is positioned on the upper surface of the second sealing member 14B, and the second light-transmitting member 12B covers the upper surface of the second sealing member 14B via the second light-adjusting member 15B. The light-adjusting members 15 reduce the brightness directly above the light-emitting element 11, thereby reducing brightness unevenness in the light-emitting module 2.

Furthermore, by placing the third light-adjusting member 16 on the upper surface 12d of the translucent member 12, the brightness directly above the light-emitting element 11 can be reduced, thereby reducing brightness unevenness in the light-emitting module 2. Either the light-adjusting member 15 or the third light-adjusting member 16 may be placed. The material of the third light-adjusting member 16 can be the same as the material of the light-adjusting member 15.

The sealing member 14 can have functions such as wavelength conversion and light diffusion depending on the particles added to it. For example, a phosphor can be included in the light-transmitting resin of the sealing member 14.

The first optical path P1 of light traveling from the side of the first light-emitting element 11A toward the corner formed by the top surface and side surface of the first sealing member 14A tends to be longer than the second optical path P2 of light traveling laterally from the side of the first light-emitting element 11A. Therefore, if the first sealing member 14A contains a phosphor, the amount of phosphor excited by the light from the first light-emitting element 11A in the first optical path P1 will be greater than the amount of phosphor excited by the light from the first light-emitting element 11A in the second optical path P2, making color unevenness more likely to occur on the light-emitting surface of the first light source 10A. The optical path difference between the first optical path P1 and the second optical path P2 tends to increase as the lateral width of the first sealing member 14A increases.

Therefore, in a cross-sectional view, it is preferable that the lateral width of the first sealing member 14A is shorter than the lateral width of the first light-transmitting member 12A. This reduces the optical path difference between the first optical path P1 and the second optical path P2, thereby reducing color unevenness in the first light source 10A. For the same reason, in a cross-sectional view, it is preferable that the lateral width of the second sealing member 14B is shorter than the lateral width of the second light-transmitting member 12B.

The phosphors to be added to the sealing member 14 include yttrium aluminum garnet phosphors (e.g., (Y,Gd) ₃ (Al,Ga) _5O12 :Ce), lutetium aluminum garnet phosphors (e.g., _Lu3 (Al,Ga) _5O12 :Ce), terbium aluminum garnet phosphors (e.g., _Tb3 (Al,Ga) _5O12 :Ce), CCA phosphors (e.g., _{Ca10 ( PO4 ) 6Cl2} :Eu), _SAE phosphors ₍ e.g., _Sr4Al14O25 : _{Eu )} , _{and chlorosilicate} phosphors (e.g., _{Ca8MgSi4O16Cl2 )} Oxynitride phosphors such as (Ba,Sr,Ca,Mg) _₂SiO₄ :Eu), silicate phosphors (e.g., (Si,Al) _₃ (O,N _{) ₄} :Eu), or α-sialon phosphors (e.g., Ca(Si,Al) _₁₂ (O,N) _₁₆ :Eu), LSN phosphors (e.g., (La, _Y ) _{₃Si₆N₁₁ :} Ce), _BSESN phosphors (e.g., (Ba,Sr) _{₂Si₅N₁₆} :Eu), SLA phosphors (e.g., _{SrLiAl₃N₄} :Eu), CASN phosphors (e.g., _{CaAlSiN₃ :} Eu), or SCASN phosphors (e.g., ( _Sr ,Ca) _AlSiN₃ Nitride _- based phosphors such as Eu, KSF-based phosphors (e.g., _K₂SiF₆ :Mn), KSAF-based phosphors (e.g., _K₂ (Si₁ _{- xAl₂} ) _F₆-x :Mn, where x satisfies 0 < x < 1), or fluoride-based phosphors such as MGF-based phosphors (e.g., _3.5MgO・0.5MgF₂・_GeO₂ :Mn), quantum dots having a perovskite structure (e.g., (Cs,FA,MA)(Pb,Sn)(F,Cl,Br,I) _³ , where FA and MA represent formamidinium and methylammonium, respectively), Group II-VI quantum dots (e.g., CdSe), Group III-V quantum dots (e.g., InP), or quantum dots having a chalcopyrite structure (e.g., (Ag,Cu)(In,Ga)(S,Se) ₂ ) etc. may be used. As the phosphor added to the sealing member 14, one type of phosphor may be used, or multiple types of phosphors may be used.

Furthermore, the wavelength conversion sheet containing the aforementioned phosphor may be placed on the light-emitting module 1 of the first embodiment, on the light-emitting module 2 of the second embodiment, or on the light-emitting module 3 of the third embodiment, which will be described later.

The wavelength conversion sheet can be a light-emitting module that absorbs a portion of the light from the light source 10, emitting yellow light, green light, and/or red light, and then emitting white light. For example, white light can be obtained by combining a light source 10 capable of emitting blue light with a wavelength conversion sheet containing a phosphor capable of emitting yellow light. Alternatively, a light source 10 capable of emitting blue light may be combined with a wavelength conversion sheet containing red and green phosphors. Furthermore, a light source 10 capable of emitting blue light may be combined with multiple wavelength conversion sheets. As for the multiple wavelength conversion sheets, for example, a wavelength conversion sheet containing a phosphor capable of emitting red light and a wavelength conversion sheet containing a phosphor capable of emitting green light can be selected. Alternatively, a light source 10 having a light-emitting element 11 capable of emitting blue light and a sealing member 14 containing a phosphor capable of emitting red light may be combined with a wavelength conversion sheet containing a phosphor capable of emitting green light.

For the yellow-emitting phosphor used in the wavelength conversion sheet, it is preferable to use, for example, the yttrium-aluminum-garnet-based phosphor described above. For the green-emitting phosphor used in the wavelength conversion sheet, it is preferable to use a quantum dot with a narrow full width at half maximum (FWHM) of its emission peak wavelength, such as the perovskite structure, III-V quantum dots, or chalcopyrite structure described above. For the red-emitting phosphor used in the wavelength conversion sheet, similar to the green-emitting phosphor, it is preferable to use a quantum dot with a narrow FWHM of its emission peak wavelength, such as the KSF-based phosphor, KSAF-based phosphor, III-V quantum dots, or chalcopyrite structure described above. In particular, quantum dot phosphors are suitable for use in light-emitting modules that perform local dimming, which individually controls the emission of light sources 10, due to their short afterglow time.

[Third Embodiment]
Next, with reference to Figure 6, the light-emitting module 3 of the third embodiment will be described.

The third embodiment of the light-emitting module 3 comprises a substrate 50, three or more light sources 10 arranged on the substrate 50, and a light-shielding member 30 arranged between each light source 10. In Figure 6, the light source 10 of the second embodiment is shown as an example, but the light-emitting module 3 may also include the light source 10 of the first embodiment. The three or more light sources 10 include a first light source 10A, a second light source 10B, and a third light source 10C having the aforementioned arrangement relationship. Figure 6 shows, for example, 12 light sources 10, but the number of light sources 10 included in the light-emitting module 3 is not limited to this.

In a plan view, the substrate 50 has a long side 50a extending in the first direction X and a short side 50b extending in the second direction Y, which is shorter than the long side 50a. That is, the light-emitting module 3 has a rectangular light source arrangement area, or in other words, a rectangular light-emitting surface. Furthermore, the shortest distance dX between adjacent light sources 10 in the first direction X is between 0.9 and 1.1 times the shortest distance dY between adjacent light sources 10 in the second direction Y. The shortest distance between adjacent light sources 10 is substantially the same in both the first direction X and the second direction Y. This reduces brightness unevenness on the light-emitting surface of the light-emitting module 3. By increasing the number of light sources 10 aligned in the first direction X (where the long side 50a, longer than the short side 50b, extends) compared to the number of light sources 10 aligned in the second direction Y (where the short side 50b extends), brightness unevenness on the rectangular light-emitting surface can be reduced.

Furthermore, according to the third embodiment, the length LX of the translucent member 12 in the first direction X is longer than the length LY of the translucent member 12 in the second direction Y. This reduces costs by decreasing the number of light sources 10 arranged in the first direction X, while also reducing brightness unevenness caused by an increase in the shortest distance dX between adjacent light sources 10 in the first direction X.

Next, a first modified example of the light source of the embodiment will be described with reference to Figures 7 and 8.

In a plan view, for example, the upper surface of the light-emitting element 11 has four corners, and the upper surface 12d of the light-transmitting member 12 also has four corners. In a plan view, each corner of the upper surface of the light-emitting element 11 faces each corner of the upper surface 12d of the light-transmitting member 12.

The translucent member 12 has a first groove 19a and a second groove 19b. Light guided within the translucent member 12 is easily extracted upwards from the first groove 19a and the second groove 19b. Furthermore, in a plan view, the first groove 19a and the second groove 19b are located between the corners of the light-emitting element 11 and the corners of the upper surface 12d of the translucent member 12. Therefore, the brightness near the corners, where brightness tends to decrease relatively on the upper surface of the light source 10, can be improved, and brightness unevenness on the upper surface of the light source 10 can be reduced.

The first groove 19a and the second groove 19b may be air layers, or light-reflective members may be placed within the first groove 19a and the second groove 19b.

In the example shown in Figure 7, in a plan view, the first groove 19a and the second groove 19b are parallel to each other and extend in a direction that intersects the direction connecting the corner of the upper surface of the light-emitting element 11 and the corner of the upper surface 12d of the light-transmitting member 12. In a plan view, the length of the first groove 19a is longer than the length of the second groove 19b. In a plan view, the first groove 19a is located closer to the corner of the upper surface of the light-emitting element 11 than the second groove 19b, and the second groove 19b is located closer to the corner of the upper surface 12d of the light-transmitting member 12 than the first groove 19a.

In the example shown in Figure 8, the first groove 19a and the second groove 19b have openings in the upper surface 12d of the translucent member 12. The first groove 19a and the second groove 19b do not penetrate the translucent member 12, and the bottoms of the first groove 19a and the second groove 19b are located within the translucent member 12.

The light source 10 of the first embodiment can be obtained, for example, by the following steps.
1. A step of embedding a first structure, including a light-emitting element 11, a light-adjusting member 15, and an electrode 17, into a translucent member 12 that is in a fluid state.
2. A step of embedding the first structure in the translucent member 12, and then curing the translucent member 12.
3. After curing the light-transmitting member 12, a step is taken to form a light-reflecting member 13 on the lower surface of the light-transmitting member 12 and the lower surface of the light-emitting element 11.

The light source 10 of the second embodiment can be obtained, for example, by the following steps.
1. A step of embedding a second structure, which includes a light-emitting element 11, a sealing member 14, a light-adjusting member 15, and an electrode 17, into a translucent member 12 that is in a fluid state.
2. A step of embedding the second structure in the translucent member 12, and then curing the translucent member 12.
3. After curing the light-transmitting member 12, a step is taken to form the light-reflecting member 13 on the lower surface of the light-transmitting member 12, the lower surface of the sealing member 14, and the lower surface of the light-emitting element 11.
4. After curing the light-transmitting member 12, a third light-adjusting member 16 is formed on the upper surface 12d of the light-transmitting member 12.

Furthermore, as shown in Figure 9, the light source may be manufactured by placing the second structure in a recess 12g formed in a sheet-like or plate-like translucent member 12 via an adhesive member 18. A translucent adhesive member 18 is interposed between the side surface of the sealing member 14 and the translucent member 12.

Alternatively, the light source may be manufactured by placing the first structure described above into a recess 12g formed in a sheet-like or plate-like translucent member 12 via an adhesive member 18.

The shape of the translucent member 12 described above is, for example, a rectangular parallelepiped. However, it is not limited to this; the translucent member 12 may also be a convex lens. In this case, the surface of the convex lens located above the light-emitting element 11 becomes the upper surface of the translucent member 12, and the surface facing the side of the light-emitting element 11 becomes the side surface of the translucent member 12.

Embodiments of the present invention include the following light-emitting module.

1. The circuit board and
A first light source disposed on the substrate, the first light source comprising a first light-emitting element, a first light-transmitting member covering the side surface of the first light-emitting element, and a first light-reflecting member covering the lower surface of the first light-transmitting member,
A second light source disposed on the substrate, the second light source comprising a second light-emitting element, a second light-transmitting member covering the side surface of the second light-emitting element, and a second light-reflecting member covering the lower surface of the second light-transmitting member,
A light-shielding member that is in contact with the side surface of the first light-transmitting member, the side surface of the first light-reflective member, the bottom surface of the first light-reflective member, the side surface of the second light-transmitting member, the bottom surface of the second light-reflective member, and the top surface of the substrate,
A light-emitting module equipped with the following features.
2. The light-emitting module according to claim 1, wherein the first light source has a first sealing member located between the first light-emitting element and the first light-transmitting member in a plan view.
3. The light-emitting module according to item 2 above, wherein the first light-reflective member covers the lower surface of the first light-emitting element and the lower surface of the first sealing member.
4. The first light source is a light-emitting module according to any one of 1 to 3 above, having a first light-adjusting member that covers the upper surface of the first light-emitting element.
5. The light-emitting module according to any one of 1 to 4 above, wherein the entire upper surface of the first light-transmitting member is exposed from the light-shielding member.
6. The light-emitting module according to any one of 1 to 5 above, wherein a part of the side surface of the first light-transmitting member is exposed from the light-shielding member.
7. The light-emitting module according to any one of 1 to 6 above, wherein at least a portion of the upper surface of the light-shielding member is located above the upper surface of the first light-emitting element.
8. The first sealing member includes a phosphor,
In a cross-sectional view, the lateral width of the first sealing member is shorter than the lateral width of the first light-transmitting member, as described in 2 or 3 above.
9. Further comprising a first conductive member that electrically connects the first light source and the substrate,
A light-emitting module according to any one of 1 to 8, wherein a gap is located between the first conductive member and the light-shielding member in contact with the lower surface of the first light-reflective member.
10. Further comprising a third light source disposed on the substrate,
The first light source and the second light source are positioned side by side in the first direction,
The first light source and the third light source are positioned side by side in a second direction perpendicular to the first direction,
The light-emitting module according to any one of claims 1 to 9, wherein the shortest distance between the first light source and the second light source in the first direction is 0.9 times or more and 1.1 times or less the shortest distance between the first light source and the third light source in the second direction.
11. In a plan view, the substrate has a long side extending in the first direction and a short side extending in the second direction that is shorter than the long side.
The light-emitting module according to 10, wherein the length of the first light-transmitting member in the first direction is longer than the length of the first light-transmitting member in the second direction.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that a person skilled in the art can implement by appropriately modifying the design based on the above-described embodiments of the present invention also fall within the scope of the present invention, as long as they encompass the gist of the present invention. Furthermore, within the scope of the idea of the present invention, a person skilled in the art can conceive of various modifications and alterations, and these modifications and alterations also fall within the scope of the present invention.

1-3…Light-emitting module, 10…Light source, 10A…First light source, 10B…Second light source, 10C…Third light source, 11…Light-emitting element, 11A…First light-emitting element, 11B…Second light-emitting element, 12…Transparent member, 12A…First translucent member, 12B…Second translucent member, 13…Light-reflective member, 13A…First light-reflective member, 13B…Second light-reflective member, 14…Sealing member, 14A…First sealing member, 14B ...Second sealing member, 15...Light adjusting member, 15A...First light adjusting member, 15B...Second light adjusting member, 16...Third light adjusting member, 17...Electrode, 18...Adhesive member, 19a...First groove, 19b...Second groove, 30...Light-shielding member, 40...Conductive member, 40A...First conductive member, 40B...Second conductive member, 50...Substrate, 50a...Long side, 50b...Short side, 51...Insulating member, 52...Wiring section, 60...Gap

Claims (11)

circuit board and
A first light source disposed on the substrate, the first light source comprising a first light-emitting element, a first light-transmitting member covering the side surface of the first light-emitting element, and a first light-reflecting member covering the lower surface of the first light-transmitting member,
A second light source disposed on the substrate, the second light source comprising a second light-emitting element, a second light-transmitting member covering the side surface of the second light-emitting element, and a second light-reflecting member covering the lower surface of the second light-transmitting member,
A light-shielding member that is in contact with the side surface of the first light-transmitting member, the side surface of the first light-reflective member, the bottom surface of the first light-reflective member, the side surface of the second light-transmitting member, the bottom surface of the second light-reflective member, and the top surface of the substrate,
A light-emitting module equipped with the following features. The light-emitting module according to claim 1, wherein the first light source has a first sealing member located between the first light-emitting element and the first translucent member in a plan view. The light-emitting module according to claim 2, wherein the first light-reflective member covers the lower surface of the first light-emitting element and the lower surface of the first sealing member. The light-emitting module according to any one of claims 1 to 3, wherein the first light source has a first light-adjusting member covering the upper surface of the first light-emitting element. The light-emitting module according to any one of claims 1 to 3, wherein the entire upper surface of the first light-transmitting member is exposed from the light-shielding member. The light-emitting module according to any one of claims 1 to 3, wherein a portion of the side surface of the first light-transmitting member is exposed from the light-shielding member. The light-emitting module according to any one of claims 1 to 3, wherein at least a portion of the upper surface of the light-shielding member is located above the upper surface of the first light-emitting element. The first sealing member includes a phosphor,
The light-emitting module according to claim 2 or 3, wherein, in a cross-sectional view, the lateral width of the first sealing member is shorter than the lateral width of the first light-transmitting member. The first light source and the substrate are further provided with a first conductive member that electrically connects them.
The light-emitting module according to any one of claims 1 to 3, wherein a gap is located between the first conductive member and the light-shielding member in contact with the lower surface of the first light-reflective member. The third light source is further provided on the substrate,
The first light source and the second light source are positioned side by side in the first direction,
The first light source and the third light source are positioned side by side in a second direction perpendicular to the first direction,
The light-emitting module according to any one of claims 1 to 3, wherein the shortest distance between the first light source and the second light source in the first direction is 0.9 times or more and 1.1 times or less the shortest distance between the first light source and the third light source in the second direction. In a plan view, the substrate has a long side extending in the first direction and a short side extending in the second direction that is shorter than the long side.
The light-emitting module according to claim 10, wherein the length of the first light-transmitting member in the first direction is longer than the length of the first light-transmitting member in the second direction.