Light-emitting device, light-emitting device module, and vehicle lighting unit

A light-emitting device module comprising:

• a plurality of flip-chip type light-emitting devices, each having four sides including a first side, the first sides thereof being aligned on one line, each of the flip-chip type light-emitting devices having a rectangular light-transmitting substrate and the first sides of the flip-chip type light-emitting devices being perpendicular to electrode rows on the rectangular light-transmitting substrate;
• and a first electrode and a second electrode opposed to the light-transmitting substrate, each of the flip-chip type light-emitting devices being mounted such that opposed two sides of the rectangular light-transmitting substrate are directed in a horizontal direction,
• each of the flip-chip type light-emitting devices comprising:
• the rectangular light-transmitting substrate;
• an underlayer semiconductor layer formed on the rectangular light-transmitting substrate;
• a plurality of the first electrodes formed on the underlayer semiconductor layer in an island shape;
• a light-emitting semiconductor layer including a light-emitting layer formed on the underlayer semiconductor layer, the light-emitting semiconductor layer configured to surround and separate respective first electrodes;
• and
• the second electrode formed on the light-emitting semiconductor layer, wherein
• the first electrodes are arranged to form a plurality of electrode rows parallel with one side of the rectangular light-transmitting substrate,
• when, among horizontal lines perpendicular to a direction in which the electrode rows are arranged and parallel with the two opposed sides of the rectangular light-transmitting substrate, two horizontal lines each crossing any of the first electrodes with a maximum electrode width of the first electrode and closest to the two sides are defined as two reference horizontal lines, and the first electrodes in the two adjacent electrode rows are arranged on any horizontal lines between the two reference horizontal lines,
• the two adjacent electrode rows are formed such that a total of the electrode widths of the first electrodes on any of the horizontal lines between the two reference horizontal lines is 35% or more and 65% or less of a total of the maximum electrode widths of the two first electrodes crossing the two reference horizontal lines.

A light-emitting device module comprising:

• a plurality of flip-chip type light-emitting devices,
• the flip-chip type light-emitting device having a rectangular light-transmitting substrate;
• and a first electrode and a second electrode opposed to the light-transmitting substrate, the flip-chip type light-emitting device being mounted such that two opposed sides of the rectangular light-transmitting substrate are directed in a horizontal direction,
• the flip-chip type light-emitting device comprising:
• the rectangular light-transmitting substrate;
• an underlayer semiconductor layer formed on the rectangular light-transmitting substrate;
• a plurality of the first electrodes formed on the underlayer semiconductor layer in an island shape;
• a light-emitting semiconductor layer including a light-emitting layer formed on the underlayer semiconductor layer, the light-emitting semiconductor layer configured to surround and separate respective first electrodes;
• and
• a second electrode formed on the light-emitting semiconductor layer, wherein
• the first electrodes are arranged to form a plurality of electrode rows parallel with one side of the rectangular light-transmitting substrate,
• when, among horizontal lines perpendicular to a direction in which the electrode rows are arranged and parallel with the two opposed sides of the rectangular light-transmitting substrate, two horizontal lines each crossing any of the first electrodes with a maximum electrode width of the first electrode and closest to the two sides are defined as two reference horizontal lines, and the first electrodes in the two adjacent electrode rows are arranged on any horizontal lines between the two reference horizontal lines,
• the two adjacent electrode rows are formed such that a total of the electrode widths of the first electrodes on any of the horizontal lines between the two reference horizontal lines is 35% or more and 65% or less of a total of the maximum electrode widths of the two first electrodes crossing the two reference horizontal lines,
• the electrode rows of the first electrodes provided to the respective flip-chip type light-emitting devices are parallel to each other.

A vehicle lighting unit including an optical axis, the vehicle lighting unit comprising:

• a light-emitting device module, including:
• a plurality of flip-chip type light-emitting devices, each having four sides including a first side, the first sides being aligned on one line, the flip-chip type light-emitting device having a rectangular light-transmitting substrate, and the first sides being perpendicular to electrode rows on the rectangular light-transmitting substrate;
• and a first electrode and a second electrode opposed to the light-transmitting substrate, the flip-chip type light-emitting device being mounted such that two opposed sides of the rectangular light-transmitting substrate are directed in a horizontal direction,
• the light-emitting device comprising:
• the rectangular light-transmitting substrate;
• an underlayer semiconductor layer formed on the rectangular light-transmitting substrate;
• a plurality of the first electrodes formed on the underlayer semiconductor layer in an island shape;
• a light-emitting semiconductor layer including a light-emitting layer formed on the underlayer semiconductor layer, the light-emitting semiconductor layer configured to surround and separate the respective first electrodes;
• and
• a second electrode formed on the light-emitting semiconductor layer, wherein
• the first electrodes are arranged to form a plurality of electrode rows parallel with one side of the rectangular light-transmitting substrate,
• when, among horizontal lines perpendicular to a direction in which the electrode rows are arranged and parallel with the two opposed sides of the rectangular light-transmitting substrate, two horizontal lines each crossing any of the first electrodes with a maximum electrode width of the first electrode and closest to the two sides are defined as two reference horizontal lines, and the first electrodes in the two adjacent electrode rows are arranged on any horizontal lines between the two reference horizontal lines,
• the two adjacent electrode rows are formed such that the total of the electrode widths of the first electrodes on any of the horizontal lines between the two reference horizontal lines is 35% or more and 65% or less of a total of the maximum electrode widths of the two first electrodes crossing the two reference horizontal lines;
• a base portion to which the light-emitting device module is secured so as to allow a longitudinal direction of the light-emitting device module to be horizontal when viewed from front while the light-emitting device module faces frontward;
• and
• a projection lens disposed on the optical axis extending forward from the light-emitting device module on the base portion, for projecting light emitted from the light-emitting device module forward.

A vehicle lighting unit comprising:

• the light-emitting device module, including:
• a plurality of flip-chip type light-emitting devices,
• each of the flip-chip type light-emitting devices having a rectangular light-transmitting substrate;
• and a first electrode and a second electrode opposed to the light-transmitting substrate, each of the flip-chip type light-emitting devices being mounted such that opposed two sides of the rectangular light-transmitting substrate are directed in a horizontal direction,
• each of the flip-chip type light-emitting devices comprising:
• the rectangular light-transmitting substrate;
• an underlayer semiconductor layer formed on the rectangular light-transmitting substrate;
• a plurality of the first electrodes formed on the underlayer semiconductor layer in an island shape;
• a light-emitting semiconductor layer including a light-emitting layer formed on the underlayer semiconductor layer, the light-emitting semiconductor layer configured to surround and separate the respective first electrodes;
• and
• a second electrode formed on the light-emitting semiconductor layer, wherein
• the first electrodes are arranged to form a plurality of electrode rows parallel with one side of the rectangular light-transmitting substrate,
• when, among horizontal lines perpendicular to a direction in which the electrode rows are arranged and parallel with the two opposed sides of the rectangular light-transmitting substrate, two horizontal lines each crossing any of the first electrodes with a maximum electrode width of the first electrode and closest to the two sides are defined as two reference horizontal lines, and the first electrodes in the two adjacent electrode rows are arranged on any horizontal lines between the two reference horizontal lines,
• the two adjacent electrode rows are formed such that the total of the electrode widths of the first electrodes on any of the horizontal lines between the two reference horizontal lines is 35% or more and 65% or less of a total of the maximum electrode widths of the two first electrodes crossing the two reference horizontal lines,
• the electrode rows of the first electrodes provided to the respective flip-chip type light-emitting devices are parallel to each other;
• and
• a projection optical system for projecting a light source image of the light-emitting device module forward so as to form a light distribution pattern for a headlamp including a cut-off line on a virtual vertical screen assumed to be disposed in front of a vehicle body, wherein
• the projection optical system is configured such that image portions corresponding to the electrode rows are arranged perpendicular to the horizontal line of the cut-off line in the light distribution pattern.

A flip-chip type light-emitting device, comprising:

• a rectangular light-transmitting substrate defined by a first side and a second side opposed to each other and a third side and a fourth side both perpendicular to the first side;
• a first electrode and a second electrode both formed on a same surface of the rectangular light-transmitting substrate;
• an underlayer semiconductor layer formed on the rectangular light-transmitting substrate;
• a plurality of the first electrodes formed on the underlayer semiconductor layer in an island shape;
• a light-emitting semiconductor layer including a light-emitting layer formed on the underlayer semiconductor layer, the light-emitting semiconductor layer configured to surround and separate the respective first electrode;
• and
• a second electrode formed on the light-emitting semiconductor layer, wherein
• the first electrodes are arranged to form a plurality of electrode rows including at least a first electrode row and a second electrode row parallel with the first side of the rectangular light-transmitting substrate;
• when, among parallel lines crossing the first electrode in the first electrode row closest to the third side of the rectangular light-transmitting substrate and parallel with the third side, a parallel line crossing the first electrode in the first electrode row with a maximum electrode width is defined as a third side reference line,
• when, among parallel lines crossing the first electrode in the second electrode row closest to the fourth side of the rectangular light-transmitting substrate and parallel with the fourth side, a parallel line crossing the first electrode in the second electrode row with a maximum electrode width is defined as a fourth side reference line,
• the first electrodes are arranged such that any parallel lines parallel with the third side between the third side reference line and the fourth side reference line cross any of the first electrodes,
• the total of an electrode width of the first electrode in the first electrode row and an electrode width of the first electrode in the second electrode row crossing the parallel line parallel with the third side are 35% or more and 65% or less of a total of the maximum electrode widths of the first electrodes crossing the two reference lines.