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US-12628472-B2 - Light emitting device

US12628472B2US 12628472 B2US12628472 B2US 12628472B2US-12628472-B2

Abstract

The present invention relates to a light emitting device comprising a first main layer of an electrically conducting material, a second main layer of an electrically conducting material and a light emitting unit between the first main layer and the second main layer, wherein the light emitting unit comprises a light emitting layer, and wherein the first main layer and/or the second main layer has a light exit orifice aligned with a section of the light emitting layer. The light emitting device can utilise impact ionisation to emit UV-C light.

Inventors

  • Ashok Chaudhari
  • Lars Frederiksen
  • Ratnakar D. Vispute

Assignees

  • BALDR LIGHT APS

Dates

Publication Date
20260512
Application Date
20220309
Priority Date
20210309

Claims (17)

  1. 1 . A light emitting device comprising a first main layer of an electrically conducting material, a second main layer of an electrically conducting material and a light emitting unit between the first main layer and the second main layer, wherein the light emitting unit comprises a light emitting layer comprising a crystal of MgO with a crystal orientation of <111>, and wherein the first main layer or the second main layer has a light exit orifice aligned with a section of the light emitting layer.
  2. 2 . The light emitting device according to claim 1 , wherein the light emitting layer has a dimension between the first main layer and the second main layer in the range of 100 nm to 1 μm.
  3. 3 . The light emitting device according to claim 1 , wherein the crystal of MgO has a dimension between the first main layer and the second main layer in the range of 1 μm to 1 mm.
  4. 4 . The light emitting device according to claim 3 , wherein the light emitting unit further comprises a first dielectric layer arranged between the first main layer and the light emitting layer, or a second dielectric layer arranged between the second main layer and the light emitting layer.
  5. 5 . The light emitting device according to claim 1 , wherein the light emitting device does not comprise an electric connection between the first and the second main layers.
  6. 6 . The light emitting device according to claim 3 , wherein the light emitting unit further comprises a first dielectric layer arranged between the first main layer and the light emitting layer, which first dielectric layer comprises an MgO film, and which light emitting layer comprises Mg x Zn 1-x O, wherein 0.6≤x≤1.
  7. 7 . The light emitting device according to claim 1 , wherein the first main layer or the second main layer is made from metal and has a thickness in the range of 0.5 mm to 5 mm.
  8. 8 . The light emitting device according to claim 1 , wherein a smallest dimension of the light exit orifice is in the range of 0.1 mm to 10 mm.
  9. 9 . The light emitting device according to claim 1 , further comprising a transparent intermediary layer aligned with the light exit orifice and arranged between the light emitting layer and the first main layer or between the light emitting layer and the second main layer.
  10. 10 . The light emitting device according to claim 1 , wherein the light emitting unit is configured to emit light by impact ionisation or wherein the light emitting unit is configured as a P-N junction diode or a Schottky diode.
  11. 11 . The light emitting device according to claim 1 , wherein the light emitting unit is formed directly on the first main layer or the second main layer.
  12. 12 . The light emitting device according to claim 1 , wherein the light emitting device forms a construction element.
  13. 13 . The light emitting device according to claim 1 , wherein the first main layer or the second main layer comprises a plurality of light exit orifices aligned with a section of the light emitting layer, the plurality of light exit orifices having a total area in the range of 20% to 90% of an area of the light emitting layer.
  14. 14 . The light emitting device according to claim 1 , wherein the light exit orifice is defined by an axial length dimension and a transverse length dimension in a surface of the main layer comprising the light exit orifice, and which axial length dimension and transverse length dimension are in the range of 1 mm to 5 mm, the light exit orifice comprising a metallic wire across the light exit orifice and electrically connected at two sites in an edge of the light exit orifice.
  15. 15 . The light emitting device according to claim 1 , wherein the light emitting device further comprises a converter for amplifying a voltage through the light emitting unit.
  16. 16 . A method of producing a light emitting device, the method comprising the steps of providing a substrate comprising a first dielectric layer, selecting a deposition process from a list consisting of: chemical vapour deposition (CVD) process, metal organic chemical vapour deposition (MOCVD) process, atomic layer deposition (ALD) process, and e-beam deposition process, depositing a crystal of MgO <111>orientation on the substrate to provide a light emitting layer, providing a first main layer of an electrically conducting material and a second main layer of an electrically conducting material, positioning the light emitting layer between the first main layer and the second main layer, and providing the first main layer or the second main layer with a light exit orifice aligned with a section of the light emitting layer.
  17. 17 . The method of claim 16 , wherein the method further comprises providing a second dielectric layer, depositing a crystal of MgO <111>orientation on the second dielectric layer, and arranging the second dielectric layer between the second main layer and the light emitting layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is the 371 National Stage of International Application No. PCT/DK2022/050041, filed Mar. 9, 2022, which claims priority to Denmark Application No. PA 2021 70105, filed Mar. 9, 2021, and Denmark PA 2021 70389, filed Jul. 20, 2021, the disclosures of which are incorporated herein by reference in their entirety. CROSS-REFERENCE TO RELATED APPLICATIONS This application is the 371 National Stage of International Application No. PCT/DK2022/050041, filed Mar. 9, 2022, which claims priority to Denmark Application No. PA 2021 70105, filed Mar. 9, 2021, and Denmark PA 2021 70389, filed Jul. 20, 2021, the disclosures of which are incorporated herein by reference in their entirety. FIELD OF THE INVENTION The present invention relates to a light emitting device comprising a first main layer of an electrically conducting material, a second main layer of an electrically conducting material and a light emitting unit between the first main layer and the second main layer. The light emitting unit can be configured to provide UV-C light that is useful for sterilising surfaces and air. BACKGROUND Composite boards are well known construction elements for light emitting diode (LED) based lamps where two electrically conducting plates separated by an insulating material are used to supply electricity to and from LEDs mounted in the composite board. The composite board thus provides both support for the LEDs and also electricity via the conducting plates. For example, WO 2015/104024 discloses a construction element where an electronic component is connected to a composite board using an appropriate adapter. WO 2015/104024 also discloses transmission of data to an electronic component in the construction element using power line communication via the electrically conducting plates. WO 2017/121430 and WO 2018/077359 disclose electrical supply systems where composite boards serve as electrical supply and extension modules for providing electricity, and data communication, to electronic components in the respective modules. The systems of WO 2017/121430 and WO 2018/077359 and the construction element of WO 2015/104024 are useful in so-called “Internet of Things (“IoT”) applications and provide flexibility for building IoT devices, but they do not generally provide functions beyond supplying electricity and data to electronic components in the respective composite boards. Ultraviolet (UV) light is commonly used for sterilising treatments, and commercially available LEDs can provide UV wavelengths in the UV-A and UV-B ranges and as an example, WO 2019/243618 discloses a board where the electronic components are UV LEDs, which may be used for sterilisation. Magnesium zinc oxide (MgZnO) is a material with an appropriate band gap energy for providing UV-C wavelengths as described by Ishii et al., 2019 (Applied Physics Express 12, 052011). However, MgZnO has not yet been employed in a practical setting for creating a lamp capable of UV sterilisation. The application of MgZnO for generation of UV light is reviewed by Lu et al. (Chin. Phys. B Vol. 26, No. 4, 2017, 047703). As explained by Lu et al., obtaining UV light with a wavelength below 300 nm is problematic, and although it has been suggested to use impact ionisation, the required high voltages produce heating that has made this approach impossible. The above-mentioned systems all employ LEDs as individual units that are mounted on or in holes in the composite boards. The present inventors believe that composite boards may have further advantageous applications, and it is an object of the invention to provide a unit having further applications than suggested in the prior art. It is especially an aim to provide a UV lamp based on MgZnO, which is capable of providing sterilising UV-C light. SUMMARY A first aspect of the present invention relates to a light emitting device comprising a first main layer of an electrically conducting material, a second main layer of an electrically conducting material and a light emitting unit between the first main layer and the second main layer, wherein the light emitting unit comprises a light emitting layer, and wherein the first main layer and/or the second main layer has a light exit orifice aligned with a section of the light emitting layer. The present light emitting device has a light exit orifice aligned with a section of the light emitting layer. The light exit orifice has an edge, or perimeter, and in particular, the perimeter may be a line, e.g. a continuous line, surrounding a section of the light emitting layer. Due to the alignment of the light emitting layer and the light exit orifice, the light emitting layer has a surface from which light emitted from the light emitting layer exits the light emitting device via the light exit orifice. The light emitting layer can be described to have a surface in the light exit orifice, and in general, the surface in the light exit orifice may be co