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KR-20260062953-A - Durable cover article with optical bandpass filtering for sensors

KR20260062953AKR 20260062953 AKR20260062953 AKR 20260062953AKR-20260062953-A

Abstract

The present specification describes a cover article for a sensor comprising a substrate; and an external laminated film disposed on the substrate. The external laminated film comprises alternating high refractive index (RI) and low refractive index layers. Each of the high RI layers comprises a nitride or an oxynitride. The external laminated film may have a physical thickness of about 500 nm to 12,000 nm. The article has at least two non-overlapping wavelength bands, each band having a bandwidth of 5 nm to 200 nm and a center wavelength within a spectrum of 400 nm to 1200 nm. Additionally, for each of the at least two non-overlapping wavelength bands, the article exhibits (a) an average bilateral transmittance greater than 70% within an incident angle of 0° to 20°, and (b) an average bilateral transmittance less than 50% within an incident angle of 20° to 90°.

Inventors

  • 하트, 샨돈 디
  • 코흐, 3세, 칼 윌리엄
  • 코식 윌리엄스, 카를로 앤서니
  • 린, 린
  • 문동건
  • 오정홍
  • 장, 원레이

Assignees

  • 코닝 인코포레이티드

Dates

Publication Date
20260507
Application Date
20240819
Priority Date
20230914

Claims (20)

  1. As a cover item, A substrate comprising an outer main surface and an inner main surface, wherein the outer and inner main surfaces are opposite each other; and It includes an outer laminated film comprising an outermost surface disposed on the outer or inner main surface of the substrate, and The above external laminated film comprises a plurality of alternating high-refractive-index and low-refractive-index layers, and Each of the above high-refractive-index layers has a refractive index greater than the refractive index of each of the above low-refractive-index layers, The above-mentioned cover article has at least two non-overlapping wavelength bands, each band having a bandwidth of 5 nm to 200 nm and a center wavelength within a spectrum of 400 nm to 1200 nm, Additionally, the cover article exhibits, for each of the at least two non-overlapping wavelength bands, (a) an average bilateral transmittance exceeding 70% within an incident angle range of 0° to 20°, and (b) an average bilateral transmittance of less than 50% within an incident angle range of 20° to 90°.
  2. In paragraph 1, The above at least two non-overlapping wavelength bands are three non-overlapping wavelength bands, and each band has a bandwidth of 5 nm to 200 nm within a spectrum of 400 nm to 1200 nm, a cover article. As a cover article according to claim 1, the at least two non-overlapping wavelength bands are three non-overlapping wavelength bands, and each band has a bandwidth between 5 nm and 200 nm within a spectrum between 400 nm and 1200 nm.
  3. In paragraph 2, A cover article having the first non-overlapping wavelength band having a center wavelength of 450 nm to 590 nm, the second non-overlapping wavelength band having a center wavelength of 600 nm to 750 nm, and the third non-overlapping wavelength band having a center wavelength of 800 nm to 1200 nm.
  4. In any one of paragraphs 1 through 3, The above high-refractive-index layers comprise nitride, oxynitride, TiO2, Nb2O5, Ta2O5, or ZrO2, and the above low-refractive-index layers comprise oxide, and one of the above low-refractive-index layers is in direct contact with the main surface of the substrate on which the external laminated film is disposed, a cover article.
  5. In any one of paragraphs 1 through 4, A cover article having a physical thickness of about 50 μm to 5000 μm and an outer laminated film having a physical thickness of about 500 nm to about 12,000 nm.
  6. In any one of paragraphs 1 through 5, A cover article, wherein the outer laminated film further comprises a capping layer, the capping layer comprises an oxide and has a physical thickness of 5 nm to 200 nm.
  7. In any one of paragraphs 1 through 6, A cover article in which the outer laminated film exhibits a hardness of at least 8 GPa when measured by a Berkovitch indenter hardness test at a depth of about 100 nm to about 500 nm from the outermost surface of the outer laminated film.
  8. In any one of paragraphs 1 through 7, The above cover article further represents one of the following: i) Bilateral reflection color given by a* > 10 when measured at near-normal incidence of 0° to 10° using a D65 light source (CIE1964); ii) bilateral reflection color given by a* < +5 when measured at near-normal incidence of 0° to 10° using a D65 light source (CIE1964); and iii) Bilateral reflection color given by -15 < a* < +5 and -15 < b* < +15 when measured at any incident angle from 0° to 90° using a D65 light source (CIE1964).
  9. In any one of paragraphs 1 through 8, The plurality of alternating high-refractive-index and low-refractive-index layers are at least 22 layers, and more than 10 high-refractive-index layers have a physical thickness of more than 100 nm, a cover article.
  10. In any one of paragraphs 1 through 9, The above outermost high-refractive-index layer is a cover article having a physical thickness of more than 150 nm.
  11. In any one of paragraphs 1 through 10, A cover article in which more than 50% of the outermost physical thickness of the above outer laminated film is composed of a high refractive index material.
  12. In any one of paragraphs 1 through 11, The above cover article exhibits, for each of the at least two non-overlapping wavelength bands, (a) an average bilateral transmittance exceeding 85% within an incident angle range of 0° to 10° or within an incident angle range of 0° to 20°, and (b) an average bilateral transmittance of less than 30% within an incident angle range of 30° to 90° or within an incident angle range of 50° to 90°.
  13. In any one of paragraphs 1 through 11, The cover article has at least three non-overlapping wavelength bands, and for each of the at least three non-overlapping wavelength bands, the cover article exhibits (a) an average bilateral transmittance exceeding 85% within an incident angle range of 0° to 10° or within an incident angle range of 0° to 20°, and (b) an average bilateral transmittance of less than 30% within an incident angle range of 30° to 90° or within an incident angle range of 50° to 90°.
  14. As a cover item, A substrate comprising an outer main surface and an inner main surface, wherein the outer and inner main surfaces are opposite each other; and It includes an outer laminated film comprising an outermost surface disposed on the outer or inner main surface of the substrate, and The above external laminated film comprises a plurality of alternating high-refractive-index and low-refractive-index layers, and Each of the above low-refractive-index layers comprises silicon oxide, and Each of the above high-refractive-index layers comprises silicon nitride, silicon oxynitride, TiO2, Nb2O5, Ta2O5, or ZrO2 and has a refractive index greater than the refractive index of each of the above low-refractive-index layers, The above-mentioned outer laminated film has a total physical thickness of about 500 nm to 12,000 nm, The above external laminated film comprises a plurality of periods (N), each period (N) comprises a low refractive index layer and a high refractive index layer, and the plurality of periods (N) are 5 to 100 periods, and The above-mentioned cover article has at least two non-overlapping wavelength bands, each band having a bandwidth of 5 nm to 200 nm and a center wavelength within a spectrum of 400 nm to 1200 nm, Additionally, the cover article exhibits, for each of the at least two non-overlapping wavelength bands, (a) an average bilateral transmittance exceeding 70% within an incident angle range of 0° to 20°, and (b) an average bilateral transmittance of less than 50% within an incident angle range of 20° to 90°.
  15. In Paragraph 14, The above at least two non-overlapping wavelength bands are three non-overlapping wavelength bands, and each band has a bandwidth of 5 nm to 200 nm within a spectrum of 400 nm to 1200 nm, a cover article.
  16. In paragraph 15, A cover article having the first non-overlapping wavelength band having a center wavelength of 450 nm to 590 nm, the second non-overlapping wavelength band having a center wavelength of 600 nm to 750 nm, and the third non-overlapping wavelength band having a center wavelength of 800 nm to 1200 nm.
  17. In any one of paragraphs 14 through 16, A cover article having a physical thickness of 15 nm to 40 nm, wherein the first layer among the low refractive index layers comprises an oxide, is in direct contact with the main surface of the substrate on which the outer laminated film is disposed, and has a physical thickness of 15 nm to 40 nm.
  18. In any one of paragraphs 14 through 17, A cover article, wherein the outer laminated film further comprises a capping layer, the capping layer comprises an oxide and has a physical thickness of 15 nm to 125 nm.
  19. In any one of paragraphs 14 through 18, A cover article in which the outer laminated film exhibits a hardness of at least 8 GPa when measured by a Berkovitch indenter hardness test at a depth of about 100 nm to about 500 nm from the outermost surface of the outer laminated film.
  20. In any one of paragraphs 14 through 19, The above cover article further represents one of the following: i) Bilateral reflection color given by a* > 10 when measured at near-normal incidence of 0° to 10° using a D65 light source (CIE1964); ii) bilateral reflection color given by a* < +5 when measured at near-normal incidence of 0° to 10° using a D65 light source (CIE1964); and iii) Bilateral reflection color given by -15 < a* < +5 and -15 < b* < +15 when measured at any incident angle from 0° to 90° using a D65 light source (CIE1964).

Description

Durable cover article with optical bandpass filtering for sensors Cross-reference regarding related applications This application claims the benefit of priority under 35 U.S.C. §119 to U.S. Provisional Application No. 63/538,300 filed September 14, 2023, the contents of which are based on this specification and the whole is incorporated herein by reference. The present disclosure relates to durable and/or scratch-resistant cover articles for electronic devices, and more specifically to durable, scratch-resistant and/or chemical-resistant cover articles having discrete wavelength transmission bands for biometric sensors and other sensors. Cover articles are often used to protect critical devices within electronic products, provide user interfaces for input and/or display, and/or for many other functions. These products include mobile devices such as smartphones, MP3 players, smartwatches, and computer tablets. Cover articles also include construction products, transportation products (e.g., products used in automobiles, trains, aircraft, ships, etc.), instrument products, or any products requiring some transparency, scratch resistance, wear resistance, or a combination thereof. These applications often require scratch resistance and robust optical performance characteristics in terms of maximum light transmittance and minimum reflectance. Additionally, for certain sensor applications, cover articles can enhance sensor functionality by acting as bandpass filters with high light transmittance and low reflectance in specific wavelength bands. Optical sensors are being developed and deployed in increasing numbers and varieties for biometric sensor applications. One of the most widespread examples is the heart rate monitor found in commercial smartwatches. New versions of these sensors are being manufactured to possess increasingly more functions, such as electrocardiogram (ECG), body temperature, heart rate variability, respiratory rate, blood oxygen, blood pressure, and blood glucose detection. New form factors, including the integration of optical sensors into smart rings, smart glasses, or other wearable devices, have also been tested. Optical devices can be more robust and resistant to environmental and electrical interference compared to sensors based on measuring the electrical properties of skin or other biomaterials. These optical sensor devices can utilize laser diodes or LED emitters and photodiode detectors optimized for different wavelengths of light. In some cases, multi-wavelength photoplethysmography (PPG) can be used to improve the accuracy of biometric detection for various users with varying skin melanin content. Optical biosensing techniques such as PPGs can beneficially utilize multi-wavelength operation to enhance biometric detection or sensitivity. The benefits of multiple wavelengths may relate to different penetration depths of light within the human body. Different wavelengths can also provide different sensitivities in transmission or reflection modes. For example, reflection PPGs are often used to detect surface pulsations for heart rate monitoring in the wavelength range of 450 to 590 nm, whereas red (600 to 750 nm) or infrared (800 to 1200 nm) ranges are often selected for transmission PPGs. The specific wavelengths selected within this range are often related to the availability of LEDs or other light sources at specific wavelengths. Multi-wavelength reflection PPGs can be used to reduce heart rate detection errors caused by motion artifacts. Additionally, multi-wavelength PPGs with at least two wavelengths have been used to calculate or estimate blood oxygen saturation, blood pressure (using pulse wave transit time in some cases), and blood glucose. It should be noted that 'reflective PPG' can be used to refer to measurements where both the light source and the detector are on the same side of the body surface. However, this does not necessarily mean that the detected light is reflected from the outer surface of the skin. In contrast, particularly for red and IR wavelengths, the light is transmitted under the skin and, through numerous scattering events and a 'banana-shaped' optical path, is eventually 'reflected' from the skin to the detector. Therefore, it may be beneficial to limit the angles of light emission and detection close to the normal so that most of the light detected by the sensing system for at least one wavelength is 'transmitted and reflected' light under the surface, which is transmitted under the skin and ultimately exits from the skin on the same side from which the light was incident—that is, what can be called a reflective PPG. Therefore, there is a need for durable and/or scratch-resistant cover articles for electronic devices, more specifically, durable, scratch-resistant and/or chemical-resistant cover articles having optical functionality including discrete wavelength transmission bands for biometric sensors and other sensors. Generally, the present disclo