Thermal dissipation for wearable device

• US 10,267,970 B2
• Filed: 08/22/2017
• Issued: 04/23/2019
• Est. Priority Date: 08/22/2016
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Jones, Jr., William K., Greco, Paul M., Schabacker, Charles Robert
• Primary Examiner(s): Hicks, Charles V
• Application Number:
  US15/683,638
• Publication Number:
  US 20180052501A1
• Time in Patent Office: 609 Days
• CPC Class Codes: G02B 2027/0114 comprising dichroic elements
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0018 with means for preventing ghost images anti-reflection coatings G02B1/11
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0176 characterised by mechanical features
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 27/30 Collimators
• CPC Class Codes: G02B 5/1823 in an overlapping or superposed manner
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 5/1871 Transmissive phase gratings
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: G02B 6/0016 : Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0023 : provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0035 : provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0036 : 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 : Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• 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 6/0076 : Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/29325 : of the slab or planar or plate like form, i.e. confinement in a single transverse dimension only integrated circuit planar waveguide arrangements G02B6/12007; specially adapted for lighting G02B6/0011
• CPC Class Codes: G02B 6/34 : utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 7/008 : with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
• CPC Class Codes: G02C 11/10 : Electronic devices other than hearing aids
• CPC Class Codes: G02C 5/16 : resilient or with resilient parts
• CPC Class Codes: G06F 1/163 : Wearable computers, e.g. on a belt
• CPC Class Codes: G06F 1/203 : for portable computers, e.g. for laptops
• CPC Class Codes: G06F 1/206 : comprising thermal management
• CPC Class Codes: G06F 3/011 : Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/013 : Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06F 3/147 : using display panels
• CPC Class Codes: G09G 2320/0233 : Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2330/045 : Protection against panel overheating
• CPC Class Codes: G09G 2340/0464 : Positioning
• CPC Class Codes: G09G 3/001 : using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/002 : to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: G09G 3/2003 : Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2044 : using dithering
• CPC Class Codes: H04N 9/3102 : using two-dimensional electronic spatial light modulators micromechanical modulators as such G02B26/0833; liquid crystal modulators as such G02F1/13
• CPC Class Codes: H04N 9/3144 : Cooling systems cooling of liquid crystal cells in general G02F1/133382; cooling of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/16
• CPC Class Codes: H04N 9/3164 : using multiple light sources
• CPC Class Codes: H05K 7/20963 : Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20972 takes precedence

Abstract

A thermal monitoring and dissipation system for use with an optical device is described. The optical device includes the following: a frame defining a pair of eye openings and including a pair of arms configured to extend over the ears of a user of the optical device; a temperature monitoring system configured to monitor a distribution of heat within the frame; a display assembly configured to display content to a user of the optical device; and a processor configured to receive temperature data from the temperature monitoring system and to adjust an output of the display assembly based on variation in the distribution of heat within the frame.

Claims

1. An optical device comprising:

a display assembly configured to display content to a user of the optical device;

a frame defining a pair of eye openings and being configured to position the display assembly in front of the eyes of a user of the optical device;

a temperature monitoring system configured to monitor a distribution of heat within the frame; and

a processor configured to receive temperature data from the temperature monitoring system and to adjust an output of the display assembly by spatially shifting a position of content displayed by the display assembly in accordance with changes in a distribution of heat within the frame.

2. The optical device of claim 1, wherein the display assembly comprises one or more projectors and diffractive optics configured to both receive light from the one or more projectors and redirect the received light toward the eyes of the user of the optical device.

3. The optical device of claim 2, wherein the output of the display assembly is spatially shifted by spatially shifting the position of content emitted from the one or more projectors by an amount equivalent to one or more pixels.

4. The optical device of claim 2, wherein the processor is configured to adjust the output of the displayed content to accommodate for a change in shape of the frame resulting from a change in the distribution of heat within the frame.

5. The optical device of claim 2, further comprising one or more strain gauges distributed across the frame and wherein shifting the position of the content displayed by the display assembly is also performed in accordance with measurements made by the strain gauges.

6. The optical device of claim 1, further comprising a plurality of optical sensors mounted to the frame, wherein the processor is configured to shut down one or more of the optical sensors when a portion of the frame associated with a respective optical sensor of the plurality of optical sensors exceeds a predetermined temperature threshold.

7. The optical device of claim 1, further comprising a plurality of optical sensors mounted to the frame, wherein the spatial shifting of the position of the content is performed in response to sensor data from the temperature monitoring system showing changes in the distribution of heat within the frame corresponding to an out of alignment condition for one or more of the plurality of optical sensors.

8. An optical device comprising:

a frame assembly and defining a first eye opening and a second eye opening;

first and second projectors coupled to the frame assembly;

diffractive optics configured to receive light emitted by the first and second projectors and orient the light toward the eyes of a user;

a temperature monitoring system; and

a processor configured to spatially shift content projected by the first and second projectors in accordance with a thermal profile of the optical device measured by the temperature monitoring system.

9. The optical device of claim 8, wherein the frame assembly comprises a first frame and a second frame that is substantially more rigid than the first frame.

10. The optical device of claim 9, wherein the second frame is configured to stay substantially rigid to maintain a fixed position of the first and second eye openings relative to one another and to the first and second projectors and wherein the first frame is more flexible than the second frame.

11. The optical device of claim 9, wherein the processor is configured to spatially shift the content in response to the thermal profile indicating a misalignment between the first projector and the diffractive optics.

12. The optical device of claim 8, wherein the first and second eye openings are positioned between the first and second projectors.

13. An optical device comprising:

a display assembly;

a frame assembly coupled to the display assembly and configured to position the display assembly in front of the eyes of a user of the optical device;

a plurality of electronic devices in thermal contact with the frame assembly; and

a processor configured to adjust operation of the display assembly by spatially shifting a position of content displayed by the display assembly in accordance with temperature changes of the frame assembly.

14. The optical device of claim 13, wherein the frame assembly comprises a pair of arms joined together by a front band and an optics frame supporting the display assembly, the optics frame being coupled to an interior facing surface of the front band.

15. The optical device of claim 14, wherein the front band is coupled to the optics frame by a heat transferring layer conforming to a surface of the optics frame and a surface of the front band, the heat transferring layer being configured to transfer heat from the plurality of electronic devices mounted on the optics frame to the front band.

16. The optical device of claim 15, wherein the display assembly comprises a pair of projectors configured to project visual content into eyepieces coupled to the optics frame.

17. The optical device of claim 16, further comprising:

a temperature sensor; and

eyepieces disposed within frame openings of the optics frame,

wherein the pair of projectors are configured to adjust an angle at which the visual content is projected into the eyepieces in accordance with temperature data provided by the temperature sensor.

18. The optical device of claim 16, further comprising a heat distribution system including heat spreaders that distribute heat generated by the pair of projectors across respective ones of the pair of arms.

19. The optical device of claim 14, further comprising a heat distribution system including graphite sheets affixed to interior surfaces of the pair of arms.

20. The optical device of claim 14, wherein the pair of arms comprises a first arm fixedly coupled to the front band and a second arm flexibly coupled to the front band and configured to bend and flex to accommodate physiological features of the user.