Displays With Collimated Light Sources and Quantum Dots

• US 20180292713A1
• Filed: 08/31/2017
• Published: 10/11/2018
• Est. Priority Date: 04/10/2017
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Drolet, Jean-Jacques P., Chen, Yuan, Steckel, Jonathan S., Bita, Ion, Sizov, Dmitry S., Tai, Chia Hsuan, Leonard, John T., Wang, Lai, Lyngnes, Ove, Xin, Xiaobin, Ge, Zhibing
• Granted Patent: US 10,591,774 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/004 Scattering dots or dot-like elements, e.g. microbeads, scattering particles, nanoparticles
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0066 characterised by the light source being coupled to the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133509 Filters, e.g. light shielding masks
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133617 Illumination with ultraviolet light; Luminescent elements or materials associated to the cell
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/134309 : characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/13439 : characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/1368 : in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 : pixel
• CPC Class Codes: G02F 2202/36 : Micro- or nanomaterials
• CPC Class Codes: G02F 2203/02 : reflective
• CPC Class Codes: G02F 2203/055 : wavelength filtering
• CPC Class Codes: G06F 3/0412 : Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/044 : by capacitive means

Abstract

A display may have display layers that form an array of pixels. The display layers may include a first layer that includes a light-blocking matrix and a second layer that overlaps the first layer. The first layer may include quantum dot elements formed in openings in the light-blocking matrix. The light-blocking matrix may be formed from a reflective material such as metal. The second layer may include color filter elements that overlap corresponding quantum dot elements in the first layer. Substrate layers may be used to support the first and second layers and to support thin-film transistor circuitry that is used in controlling light transmission through the array of pixels. The display layers may include a liquid crystal layer, polarizer layers, filter layers for reflecting red and green light and/or other light to enhance light recycling, and layers with angularly dependent transmission characteristics.

Claims

1. A display, comprising:

a light source configured to produce pump light;

display layers that form an array of pixels configured to display images in response to the pump light, wherein the display layers include a first layer having at least first quantum dot elements of a first color and second quantum dot elements of a second color and include a second layer having at least first color filter elements of the first color that overlap the first quantum dot elements and second color filter elements of the second color that overlap the second quantum dot elements; and

a filter layer interposed between the first layer and the light source, wherein the filter layer is configured to reflect light of the first and second colors and pass the pump light.

2. The display defined in claim 1 wherein the display layers comprise:

a first substrate layer;

a second substrate layer; and

a liquid crystal layer interposed between the first and second substrate layers, wherein the second layer is interposed between the liquid crystal layer and the second substrate layer.

3. The display defined in claim 2 wherein the first substrate layer is interposed between the first layer and the light source and wherein the light source includes an edge-lit light guide layer.

4. The display defined in claim 2 wherein the first substrate layer is interposed between the first layer and the light source and wherein the light source comprises an array of cells each of which includes a light-emitting device.

5. The display defined in claim 4 wherein each cell in the array of cells includes a transparent layer with gratings that diffract light from the light-emitting device of that cell through the first substrate layer.

6. The display defined in claim 5 wherein the gratings form light-redirecting structures that redistribute light from the light-emitting devices through the array of pixels.

7. The display defined in claim 6 wherein the light-emitting device of each cell is a light-emitting diode configured to exhibit destructive interference in a direction perpendicular to the transparent layer and configured to exhibit constructive interference in a direction that is not perpendicular to the transparent layer.

8. The display defined in claim 5 wherein at the gratings include at least first and second gratings with different respective rotational orientations.

9. The display defined in claim 5 wherein the light-emitting device of each cell includes a light-emitting diode with a first index of refraction and wherein the transparent layer has a second index of refraction that is within 10% of the first index of refraction.

10. The display defined in claim 9 wherein the transparent layer includes openings and reflective material in the openings.

11. The display defined in claim 2 wherein the filter layer is interposed between the first substrate layer and the first layer and is formed from at least one material with a refractive index of at least 1.4 and wherein the display further comprises a layer of material between the filter layer and the first layer having an index of refraction of less than 1.3.

12. The display defined in claim 2 wherein the second substrate has a portion with recesses.

13. The display defined in claim 12 wherein the second substrate comprises a transparent material with a refractive index and wherein the recesses are patterned to reduce the refractive index of the second substrate in the portion of the second substrate facing the second layer.

14. The display defined in claim 13 wherein the display layers further comprise a glass layer adjacent to the recesses, wherein the glass layer is interposed between the second substrate layer and the second layer.

15. The display defined in claim 2 wherein the first layer has a first refractive index and wherein the display layers comprise a layer interposed between the first and second layers with a second refractive index that is lower than the first refractive index.

16. The display defined in claim 2 wherein the first layer comprises a matrix of light-blocking material with openings that receive the first and second quantum dot elements.

17. The display defined in claim 16 wherein the light-blocking material comprises metal.

18. The display defined in claim 1 wherein the light source includes blue light-emitting diodes that are configured to produce blue pump light and wherein the first layer includes diffuser elements associated with blue pixels.

19. The display defined in claim 1 wherein the light source includes ultraviolet light-emitting diodes that are configured to produce ultraviolet pump light and wherein the first layer includes blue quantum dot elements that produce blue light in response to receiving the ultraviolet pump light.

20. A display, comprising:

a light source that produces pump light;

display layers that form an array of pixels configured to display images in response to the pump light, wherein the display layers include a first layer having at least first quantum dot elements of a first color and second quantum dot elements of a second color and include a second layer having at least first color filter elements of the first color that overlap the first quantum dot elements and second color filter elements of the second color that overlap the second quantum dot elements and wherein the second layer includes a metal matrix having openings that receive the first and second quantum dot elements; and

a filter layer interposed between the first layer and the light source, wherein the filter layer is configured to reflect light of the first and second colors and pass the pump light.

21. The display defined in claim 20 wherein the light source includes a light-collimating filter with an angularly dependent transmission characteristic configured to recycle off axis light from the light source that is angled at a non-zero angle with respect to a surface normal of the display layers.

22. The display defined in claim 21 wherein the light-collimating filter comprises a holographic layer.

23. The display defined in claim 20 wherein the first layer has a first index of refraction and wherein the display layers include a layer of material between the first and second layers having a second index of refraction less than the first index of refraction.

24. A display, comprising:

a light source that produces pump light;

display layers that form an array of pixels configured to display images in response to the pump light, wherein the display layers include a first layer having at least red and green quantum dot elements and a second layer having at least red color filter elements that overlap the red quantum dot elements in red pixels of the array of pixels and green color filter elements that overlap the green quantum dot elements in green pixels of the array of pixels, wherein the first layer includes a metal matrix having openings that receive at least the red and green quantum dot elements, and wherein the red and green quantum dot elements of the first layer have a first index of refraction;

a filter layer interposed between the first layer and the light source that reflects at least red and green light and that passes the pump light; and

a layer of material between the first layer and the filter layer that has a second index of refraction that is less than the first index of refraction.