Image display element
An image display element, provided with a pixel region and a connection region, includes a light-emitting unit and a driving circuit substrate. The light-emitting unit includes a semiconductor layer obtained by layering a second conductive layer, a light-emitting layer, and a first conductive layer, mesa shapes formed by dividing the semiconductor layer, and a step portion separated from the mesa shapes by a groove. A first electrode is connected to the first conductive layer and a first driving electrode. The light-emitting unit further includes, between the mesa shapes adjacent to each other, a wiring line layer forming a conductive path, the wiring line layer being thinner than a layer thickness of a portion of each of the mesa shapes in the semiconductor layer. The wiring line layer extends to a top of the step portion and is connected to a common second electrode provided on the step portion.
1. An image display element provided with a pixel region configured to display an image and a connection region provided outside the pixel region, the image display element comprising:
a light-emitting unit including a plurality of light-emitting elements disposed in an array in the pixel region; and
a driving circuit substrate facing the light-emitting unit and configured to drive the plurality of light-emitting elements,
wherein the light-emitting unit includes
a semiconductor layer obtained by layering a second conductive layer, a light-emitting layer, and a first conductive layer in the pixel region and the connection region,
a plurality of mesa shapes formed by dividing the semiconductor layer into portions corresponding to each of the plurality of light-emitting elements in the pixel region, and
a step portion separated from the plurality of mesa shapes by a groove formed in the semiconductor layer in the connection region,
a first electrode is connected to the first conductive layer of each of the plurality of mesa shapes,
the first electrode is connected to a first driving electrode provided on an opposing surface of the driving circuit substrate facing the light-emitting unit,
the light-emitting unit further includes, between the plurality of mesa shapes adjacent to each other, a wiring line layer forming a conductive path between the second conductive layers of the plurality of mesa shapes, the wiring line layer being thinner than a layer thickness of a portion of each of the plurality of mesa shapes in the semiconductor layer,
the wiring line layer extends to a top of the step portion and is connected to a common second electrode provided on the step portion, and
the common second electrode is connected to a second driving electrode provided on the opposing surface of the driving circuit substrate.
2. The image display element according to claim 1 ,
wherein in the pixel region, the plurality of mesa shapes divide the semiconductor layer into portions corresponding to each of the plurality of light-emitting elements, leaving a portion of the second conductive layer in a layer thickness direction,
in the connection region, the step portion is separated from the plurality of mesa shapes by the groove formed in the semiconductor layer, leaving a portion of the second conductive layer in the layer thickness direction, and
the wiring line layer is connected to the portion of the second conductive layer.
3. The image display element according to claim 2 ,
wherein a protection film is formed between the wiring line layer and the semiconductor layer formed in the plurality of mesa shapes.
4. The image display element according to claim 1 ,
wherein, in the pixel region, the semiconductor layer is partitioned into portions corresponding to each of the plurality of light-emitting elements without the plurality of mesa shapes being connected to each other by the second conductive layer,
in the connection region, the semiconductor layer is partitioned in a layer thickness direction by the groove, and
the wiring line layer is connected to a side surface of the second conductive layer of each of the plurality of mesa shapes.
5. The image display element according to claim 1 ,
wherein an end portion of the wiring line layer in a longitudinal direction rises along a wall surface of a sidewall of each of the plurality of mesa shapes, and
when the plurality of mesa shapes adjacent to each other and the wiring line layer disposed between the plurality of mesa shapes adjacent to each other are cut in a short-hand direction of the wiring line layer, a cut surface of the wiring line layer has a recessed shape that opens toward the driving circuit substrate.
6. The image display element according to claim 1 ,
wherein the first electrode and the common second electrode are formed of the same electrode material.
7. The image display element according to claim 1 ,
wherein a position of a connecting surface of the first electrode with the first driving electrode and a position of a connecting surface of the common second electrode with the second driving electrode are coplanar.
8. The image display element according to claim 1 ,
wherein the first conductive layer of each of the plurality of mesa shapes and the first conductive layer of the step portion are equal in layer thickness,
the light-emitting layer of each of the plurality of mesa shapes and the light-emitting layer of the step portion are equal in layer thickness, and
the second conductive layer of each of the plurality of mesa shapes and the second conductive layer of the step portion are equal in layer thickness.
9. The image display element according to claim 1 ,
wherein the wiring line layer is constituted by a light-reflective material having higher reflectivity than gold (Au).
10. The image display element according to claim 1 ,
wherein the array of the plurality of light-emitting elements formed in the pixel region are arrayed in m rows and n columns at a constant pitch, and
odd numbered columns in a row direction are shifted by one-half the pitch with respect to even numbered columns.