Light-based sensor apparatus and associated methods

Patent metadata

Field	Value
Publication number	US-11329186-B2
Application number	US-201615770277-A
Country	US
Kind code	B2
Filing date	Oct 7, 2016
Priority date	Oct 28, 2015
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

An apparatus (201) comprises a light emitter (202) and a photodetector (203) formed on a single fluid-permeable substrate (206) such that the photodetector (203) is able to detect light emitted by the light emitter (202) after interaction of the light with a user of the apparatus (201). The photodetector comprises a channel member (207) which may be made from graphene, respective source and drain electrodes (208, 209), a layer of photosensitive material (210) configured to vary the flow of electrical current through the channel member (207) on exposure to light from the light emitter (202), and a gate electrode (211). The apparatus (201) further comprises a layer of fluid-impermeable dielectric material (212) configured to inhibit a flow of electrical current between the channel member (207) and the gate electrode (211) of the photodetector (203) to enable the electrical conductance of the channel member (207) to be controlled by a voltage applied to the gate electrode (211) and to inhibit exposure of the light emitter (202) to fluid which has permeated through the fluid-permeable substrate (206). The layer of fluid-impermeable dielectric material (212) allows resilient substrates made from polymeric material to be used without the risk of damage to the overlying components caused by the permeated fluid. The dual functionality of the layer of fluid-impermeable dielectric material (212) reduces the number of fabrication steps used to form the apparatus (201) and results in a thinner, more compact device.

First claim

The invention claimed is:

1. An apparatus comprising:
a fluid-permeable substrate;
a gate electrode of a photodetector embedded within the fluid-permeable substrate;
a layer of fluid-impermeable dielectric material covering the fluid-permeable substrate and the gate electrode;
a light emitter on the layer of fluid-impermeable dielectric material;
a channel member, a source electrode, and a drain electrode of the photodetector on the layer of fluid-impermeable dielectric material, the source electrode and the drain electrode being separated from one another on the channel member, the source electrode and the drain electrode enabling a flow of electrical current through the channel member between the source electrode and the drain electrode, a layer of photosensitive material being included between the source electrode and the drain electrode on the channel member, the layer of photosensitive material being configured to vary the flow of electrical current through the channel member on exposure to light from the light emitter, the channel member being separated from the gate electrode by the layer of fluid-impermeable dielectric material,
wherein the layer of fluid-impermeable dielectric material inhibits the flow of electrical current between the channel member and the gate electrode to enable the electrical conductance of the channel member to be controlled by a voltage applied to the gate electrode, and inhibits exposure of the light emitter to fluid permeating through the fluid-permeable substrate.

2. The apparatus of claim 1 , wherein the fluid-permeable substrate comprises one or more resilient polymeric materials.

3. The apparatus of claim 1 , wherein the layer of fluid-impermeable dielectric material is configured to facilitate the dissipation of heat produced by the light emitter.

4. The apparatus of claim 1 , wherein the fluid-impermeable dielectric material under the light emitter has a different thickness than the fluid-impermeable dielectric material under the channel member.

5. The apparatus of claim 1 , wherein the layer of fluid-impermeable dielectric material has a thickness between 10 nm and 200 nm, and a surface roughness of less than 25 nm.

6. The apparatus of claim 1 , wherein the light emitter and the channel member, the source electrode, and the drain electrode of the photodetector are formed on the layer of fluid-impermeable dielectric material to enable the photodetector to detect light emitted by the light emitter after reflection of the light from a body part of a user or transmission of the light through the body part of the user.

7. The apparatus of claim 6 , wherein the fluid-permeable substrate and the layer of fluid-impermeable dielectric material are resilient to enable the light emitter and photodetector to be positioned on opposite sides of the body part of the user by mechanical deformation of the fluid-permeable substrate and the layer of fluid-impermeable dielectric material such that the photodetector detects light transmitted through the body part of the user.

8. The apparatus of claim 1 , wherein the light emitter and photodetector are encapsulated within a fluid-impermeable material to inhibit their exposure to fluid in the surrounding environment.

9. The apparatus of claim 1 , wherein the fluid comprises water, or oxygen, or both water and oxygen.

10. The apparatus of claim 1 , wherein the layer of fluid-impermeable dielectric material prevents exposure of the light emitter to 50% or more of the fluid permeating through the fluid-permeable substrate.

11. The apparatus of claim 1 , wherein the apparatus is one or more of an electronic device, a portable electronic device, a portable telecommunications device, a mobile phone, a personal digital assistant, a tablet, a phablet, a desktop computer, a laptop computer, a server, a smartphone, a smartwatch, smart eyewear, a sensor, an SpO2 sensor, a blood pressure sensor, a pulse sensor, and a module for one or more of the same.

12. A method of making an apparatus, the method comprising:
providing a fluid-permeable substrate;
forming a gate electrode of a photodetector embedded within the fluid-permeable substrate;
covering the fluid-permeable substrate and the gate electrode with a layer of fluid-impermeable dielectric material;
forming a light emitter on the layer of fluid-impermeable dielectric material;
forming a channel member, a source electrode, and a drain electrode of the photodetector on the layer of fluid-impermeable dielectric material, the source electrode and the drain electrode being separated from one another on the channel member, the source electrode and the drain electrode enabling a flow of electrical current through the channel member between the source electrode and the drain electrode,
forming a layer of photosensitive material between the source electrode and the drain electrode on the channel member, the layer of photosensitive material being configured to vary the flow of electrical current through the channel member on exposure to light from the light emitter, the channel member being separated from the gate electrode by the layer of fluid-impermeable dielectric material,
wherein the layer of fluid-impermeable dielectric material inhibits the flow of electrical current between the channel member and the gate electrode to enable the electrical conductance of the channel member to be controlled by a voltage applied to the gate electrode, and inhibits exposure of the light emitter to fluid permeating through the fluid-permeable substrate.

13. The method of claim 12 , wherein the fluid-permeable substrate is provided comprising one or more resilient polymeric materials.

14. The method of claim 12 , wherein the layer of fluid-impermeable dielectric material is configured via at least the covering to facilitate dissipation of heat produced by the light emitter.

15. The method of claim 12 , wherein the fluid-impermeable dielectric material under the light emitter is formed to have a different thickness than a thickness of the fluid-impermeable dielectric material under the channel member.

16. The method of claim 12 , wherein the layer of fluid-impermeable dielectric material is formed to have a thickness between 10 nm and 200 nm, and a surface roughness of less than 25 nm.

17. The method of claim 12 , wherein the light emitter and the channel member, the source electrode, and the drain electrode of the photodetector are formed on the layer of fluid-impermeable dielectric material to enable the photodetector to detect light emitted by the light emitter after reflection of the light from a body part of a user or transmission of the light through the body part of the user.

18. The method of claim 17 , wherein the fluid-permeable substrate and the layer of fluid-impermeable dielectric material are formed to be resilient to enable the light emitter and photodetector to be positioned on opposite sides of the body part of the user by mechanical deformation of the fluid-permeable substrate and the layer of fluid-impermeable dielectric material such that the photodetector detects light transmitted through the body part of the user.

19. The method of claim 12 , wherein the light emitter and photodetector are formed to be encapsulated within a fluid-impermeable material to inhibit their exposure to fluid in the surrounding environment.

20. The method of claim 12 , wherein the fluid comprises water, or oxygen, or both water and oxygen.

Assignees

• Nokia Technologies Oy
• Nokia Technolgies Oy

Inventors

• Bessonov Alexander
• Cotton Darryl
• Robinson Adam

Classifications

• H10F77/60

  Arrangements for cooling, heating, ventilating or compensating for temperature fluctuations · CPC title

• H10F30/282

  Insulated-gate field-effect transistors [IGFET], e.g. MISFET [metal-insulator-semiconductor field-effect transistor] phototransistors · CPC title

• H10F55/255 Primary

  formed in, or on, a common substrate · CPC title

• A61B5/02433

  for infrared radiation · CPC title

• A61B5/6826

  Finger · CPC title