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EP-4739048-A1 - TRANSMISSIVE DISPLAY AND LIGHT-EMITTING STRUCTURE

EP4739048A1EP 4739048 A1EP4739048 A1EP 4739048A1EP-4739048-A1

Abstract

A light-emitting structure of a transmissive display includes a plurality of pairs of electrodes arranged in an array, a plurality of transmissive light sources arranged to extend between the electrodes of respective pairs, and a reflective portion arranged in a target region including a region configured for shielding a light path, the light path extending in a direction from a portion of a rear surface of each of the plurality of light sources that faces a gap between the electrodes toward a transparent substrate.

Inventors

  • YOSHII, KATSUMASA
  • Umagami, Tomomi

Assignees

  • Alps Alpine Co., Ltd.

Dates

Publication Date
20260506
Application Date
20251028

Claims (12)

  1. A light-emitting structure for a transmissive display, the light-emitting structure comprising: a plurality of pairs of electrodes arranged in an array; a plurality of transmissive light sources arranged so as to extend between the electrodes of respective pairs; and a reflective portion arranged in a target region including a region configured for shielding a light path, the light path extending in a direction from a portion of a rear surface of each of the plurality of light sources that faces a gap between the electrodes toward a transparent substrate.
  2. The light-emitting structure for the transmissive display according to claim 1, the light-emitting structure further comprising: a stacked structure including the transparent substrate and an insulating layer, wherein the reflective portion is formed in the gap between the electrodes of each of the pairs on a same layer as a layer on which the plurality of pairs of electrodes are formed.
  3. The light-emitting structure for the transmissive display according to claim 1 or 2, the light-emitting structure further comprising: a stacked structure including the transparent substrate and an insulating layer, wherein the reflective portion is formed on a layer different from the layer on which the plurality of pairs of electrodes are formed.
  4. The light-emitting structure for the transmissive display according to claim 3, wherein the reflective portion is an interconnect electrode different from the plurality of pairs of electrodes.
  5. The light-emitting structure for the transmissive display according to claim 4, wherein the target region in which the interconnect electrode is formed is a rectangular region having edges in a first direction connecting the electrodes and edges in a second direction perpendicular to the first direction, and a length of the target region in the first direction is greater than a length of the gap between the electrodes in the first direction, and a length of the target region in the second direction is greater than a length of the gap between the electrodes in the second direction.
  6. The light-emitting structure for the transmissive display according to one of claims 1 to 5, wherein the reflective portion is a reflective layer formed of a metal film, a metal plate, or a metal sheet.
  7. The light-emitting structure for the transmissive display according to claim 6, wherein the target region in which the reflective layer is formed is a rectangular region having edges in a first direction connecting the electrodes and edges in a second direction perpendicular to the first direction, a length of the target region in the first direction is equal to or less than a greater of a maximum length between the edges of one pair of electrodes in the first direction or a length of the light source in the first direction, and a length of the target region in the second direction is equal to or less than a greater of a length of one pair of electrodes in the second direction or a length of the light source in the second direction.
  8. The light-emitting structure for the transmissive display according to one of claims 3 to 7, wherein the reflective portion is a reflective layer formed of a metal film, a metal plate, or a metal sheet, the target region in which the reflective layer is formed is a rectangular region having edges in a first direction connecting the electrodes and edges in a second direction perpendicular to the first direction, a length of the target region in the first direction is equal to or greater than a length of the gap between the electrodes in the first direction, and equal to or less than a greater of a maximum length between the edges of one pair of electrodes in the first direction or a length of the light source in the first direction, and a length of the target region in the second direction is equal to or greater than a length of the gap between the electrodes in the second direction and equal to or less than a greater of a length between the edges of one pair of electrodes in the second direction or a length of the light source in the second direction.
  9. The light-emitting structure for the transmissive display according to one of claims 6 to 8, wherein the reflective portion is a metal film formed on a front surface of the transparent substrate or the insulating layer.
  10. The light-emitting structure for the transmissive display according to one of claims 6 to 8, wherein the reflective portion is a metal plate, a metal film, or a metal sheet formed on a rear surface of the transparent substrate.
  11. The light-emitting structure for the transmissive display according to one of claims 6 to 10, the light-emitting structure further comprising: a light-shielding layer formed at a layer position farther than the reflective layer from the light source.
  12. A transmissive display comprising the light-emitting structure according to one of claims 1 to 11.

Description

The present disclosure relates to a transmissive display and a light-emitting structure. Transmissive displays, which are designed to allow the background to be seen through them unlike conventional displays, are known. In a transmissive display, a plurality of light sources are arranged in an array on a transparent substrate, and a plurality of apertures in which electrodes or the like are not arranged are provided, so that light can be transmitted from the rear surface to the front surface of the display through the apertures. An aperture ratio is a proportion of the aperture area relative to the total pixel area. A higher aperture ratio allows more background light to pass through, enabling the display to appear more transparent to the human eye. Among various types of transmissive displays, transmissive LED displays are expected to be applied to various applications because the transmissive LED displays can achieve a high transmittance of 70% or more. To construct a transmissive LED display, it is preferable to use a technology called micro-LED in which LEDs used as light sources are miniaturized and arranged in an array. FIGS. 8A and 8B are diagrams simply illustrating the structure of a light emitter of a transmissive LED display. FIG. 8A illustrates a state of the light emitter of the transmissive LED display as seen from the front surface, and FIG. 8B illustrates a state of the light emitter of the transmissive LED display as seen from the rear surface. As illustrated in FIG. 8A, a plurality of LEDs 101 are arranged in an array, and a plurality of apertures 102 are arranged in an array adjacent to the plurality of LEDs 101. The plurality of LEDs 101 are arranged to extend between respective anode electrodes 103 and cathode electrodes 104. There is a known technology in which an interconnect pattern of a circuit board on which LED chips are mounted is made of a material having light reflectivity (for example, aluminum), so that light emitted from the rear surface of the LED chips can be extracted from the front side (for example, see JP 2012-204370A). The present disclosure relates to a light-emitting structure and a transmissive display according to the appendant claims. Embodiments are disclosed in the dependent claims. A light-emitting structure for a transmissive display according to an aspect of the present disclosure includes a plurality of pairs of electrodes arranged in an array, a plurality of transmissive light sources arranged so as to extend between the electrodes of respective pairs, and a reflective portion arranged in a target region including a region configured for shielding a light path, the light path extending in a direction from a portion of a rear surface of each of the plurality of light sources that faces a gap between the electrodes toward a transparent substrate. FIGS. 1A and 1B are diagrams illustrating a configuration example of a light-emitting structure of a transmissive LED display according to a first embodiment;FIGS. 2A and 2B are diagrams for explaining an effect of the light-emitting structure according to the first embodiment;FIGS. 3A and 3B are diagrams illustrating a configuration example of a light-emitting structure of a transmissive LED display according to a second embodiment;FIGS. 4A and 4B are diagrams illustrating a configuration example of a light-emitting structure of a transmissive LED display according to a third embodiment;FIGS. 5A and 5B are diagrams illustrating a configuration example of a light-emitting structure of a transmissive LED display according to a fourth embodiment;FIGS. 6A and 6B are diagrams illustrating a configuration example of a light-emitting structure of a transmissive LED display according to a fifth embodiment;FIGS. 7A and 7B are diagrams illustrating a configuration example of a light-emitting structure of a transmissive LED display according to another embodiment; andFIGS. 8A and 8B are diagrams illustrating a structure of a light emitter of a transmissive LED display. In the transmissive LED display configured in the manner illustrated in FIGS. 8A and 8B, light emitted from the LEDs 101 for being projected onto the front surface leaks to the rear surface through gaps between the anode electrodes 103 and the cathode electrodes 104 as illustrated in FIG. 8B. However, light emitted from the LEDs 101 toward the rear surface, which is different from the observation surface on the front side, is undesirably emitted directly to the rear surface of the transmissive LED display, and becomes lost light that does not contribute to the luminance on the observer side. In other words, a micro-LED device is generally made by growing a semiconductor thin film on a sapphire substrate by epitaxial growth. Since sapphire and the semiconductor thin film are highly transmissive, light emitted from the inside of the device radiates in all directions. In the transmissive LED display, both the substrate arranged on the front side and the substrate