Stress-engineered frangible structures

• US 10,012,250 B2
• Filed: 04/06/2016
• Issued: 07/03/2018
• Est. Priority Date: 04/06/2016
• Status: Active Grant

• Current Assignee: SRI International, Inc.
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Limb, Scott J. H., Whiting, Gregory L.
• Primary Examiner(s): Wiley, Daniel J
• Application Number:
  US15/092,313
• Publication Number:
  US 20170292546A1
• Time in Patent Office: 818 Days
• CPC Class Codes: B32B 17/00 Layered products essentially comprising sheet glass, or glass, slag, or like fibres
• CPC Class Codes: B32B 17/10137 Chemical strengthening
• CPC Class Codes: C03B 23/20 Uniting glass pieces by fusing without substantial reshaping
• CPC Class Codes: C03B 23/203 Uniting glass sheets C03B23/24 takes precedence
• CPC Class Codes: C03B 27/00 Tempering or quenching glass products
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: C03C 21/00 Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
• CPC Class Codes: C03C 21/001 in liquid phase, e.g. molten salts, solutions
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 27/044 of glass, glass-ceramic or ceramic material only
• CPC Class Codes: C03C 27/06 Joining glass to glass by processes other than fusing fusing C03B23/20; units for use as elements for closing wall or like openings and comprising two or more parallel glass panes in spaced relationship, the panes being permanently secured together E06B3/66
• CPC Class Codes: C03C 27/10 with the aid of adhesive specially adapted for that purpose
• CPC Class Codes: F16B 1/00 Devices for securing together, or preventing relative movement between, constructional elements or machine parts

Abstract

A stress-engineered frangible structure includes multiple discrete glass members interconnected by inter-structure bonds to form a complex structural shape. Each glass member includes strengthened (i.e., by way of stress-engineering) glass material portions that are configured to transmit propagating fracture forces throughout the glass member. Each inter-structure bond includes a bonding member (e.g., glass-frit or adhesive) connected to weaker (e.g., untreated, unstrengthened, etched, or thinner) glass member region(s) disposed on one or both interconnected glass members that function to reliably transfer propagating fracture forces from one glass member to other glass member. An optional trigger mechanism generates an initial fracture force in a first (most-upstream) glass member, and the resulting propagating fracture forces are transferred by way of inter-structure bonds to all downstream glass members. One-way crack propagation is achieved by providing a weaker member region only on the downstream side of each inter-structure bond.

Claims

1. A stress-engineered frangible structure comprising:

a plurality of interconnected discrete glass members including a first glass member and a second glass member, each said glass member including at least one strengthened glass portion comprising a stress-engineered glass material; and

an inter-structure bond connected between said first glass member and said second glass member, said inter-structure bond including a bonding member connected between first surface regions of said first and second glass members such that said bonding member is directly connected to at least one weaker member region disposed in at least one of said first and second glass members, said at least one weaker member region comprising a structurally weaker glass material than said stress-engineered glass material of said one or more strengthened glass portions,

wherein said bonding member and said at least one weaker member region are configured to generate a transfer fracture force in response to a first propagating fracture force, said transfer fracture force being directed from said first glass member to said second glass member and having sufficient energy such that secondary propagating fracture forces are generated in said at least one strengthened glass portion of said second glass member.

2. The stress-engineered frangible structure of claim 1,

wherein said at least one weaker member region comprises one of a weakened glass portion and a weakened surface feature disposed within a second surface region of the second glass member, and

wherein said bonding member is sandwiched between said first surface regions of the first and second glass members, respectively, such that the first surface region of the second glass member that is contacted by the bonding member entirely surrounds the second surface region surrounding said at least one weaker member region.

3. The stress-engineered frangible structure of claim 1,

wherein said at least one weaker member region includes a first weakened glass portion disposed in the first glass member and a second weakened glass portion disposed in the second glass member, and

wherein said inter-structure bond comprises said bonding member sandwiched between said first surface regions of the first and second glass members, respectively, wherein the first surface regions are contiguous with and surround said first and second weakened glass portions.

4. The stress-engineered frangible structure according to claim 1, further comprising a trigger mechanism operably attached to said first glass member, said trigger mechanism being configured to generate an initial fracture force sufficient to cause said first propagating fracture force in said at least one strengthened portion of said first glass member.

5. The stress-engineered frangible structure according to claim 4, further comprising a sensor configured to detect a predetermined transmitted wave signal, and configured to generate a trigger signal upon detection of said predetermined transmitted wave signal, wherein said trigger mechanism is further configured to generate said initial fracture force in response to said trigger signal.

6. The stress-engineered frangible structure according to claim 1, wherein said at least one strengthened portion of said first and second glass members comprises one of a thermally tempered glass material, a laminated glass material, and an ion-exchange treated glass material.

7. A method for producing a stress-engineered frangible structure having a structural shape, the method comprising:

providing a plurality of discrete glass members configured to collectively form, when operably assembled, said structural shape; and

interconnecting said plurality of discrete glass members such that each said discrete glass member is directly connected by way of an associated inter-structure bond to an adjacent one of said discrete glass member,

wherein, after said interconnecting, each said glass member includes at least one strengthened portion comprising a stress-engineered glass material, and

wherein each of said one or more inter-structure bonds is configured to transfer first propagating fracture forces from said at least one strengthened portion of a first said glass member to said at least one strengthened portion of an adjacent second said glass member such that secondary propagating fracture forces are generated in said adjacent second glass member in response to said transferred first propagating forces.

8. The method of claim 7, further comprising mounting a trigger mechanism onto said first glass member, said trigger mechanism being configured to generate an initial fracture force in said first glass member, whereby said initial propagating fracture forces generated in said first glass member by said trigger mechanism are transferred by way of said one or more inter-structure bonds to all of said plurality of interconnected glass members.

9. The method of claim 8, wherein interconnecting comprises:

generating a weaker member region in the second glass member; and

connecting said first and second glass members such that a bonding member is disposed over said weaker member region.

10. The method of claim 9, wherein generating said weaker member region comprises:

providing first and second discrete untreated glass members;

forming a mask over a designated surface region of said second discrete untreated glass member;

subjecting all exposed surfaces of said first and second discrete untreated glass members to an ion-exchange treatment, whereby said first and second untreated glass members are converted into said first and second glass members with said second glass member having a weakened glass portion disposed under said mask;

removing said mask; and

connecting said first and second glass members such that said bonding member is disposed against said weakened glass portion.

11. The method of claim 9, wherein generating said weaker member region comprises:

providing first and second discrete untreated glass members;

subjecting all exposed surfaces of said first and second discrete untreated glass members to an ion-exchange treatment, whereby said first and second untreated glass members are converted into said first and second glass members including said at least one strengthened portion;

forming a weakened surface feature by removing glass material from said at least one strengthened portion of the second glass member through a designated surface region; and

connecting said first and second glass members such that said bonding member is disposed against said weakened surface feature.

12. The method of claim 11, wherein forming said weakened surface feature comprises etching said designated surface region to define one of a single cavity, a plurality of adjacent cavities, and one or more slots through said designated surface region into said second glass member.

13. The method of claim 9, wherein connecting said first and second glass members comprises applying one of a ceramic adhesive, a low temperature glass frit, an anodic bonding structure, and a chemical bond.

14. The method of claim 7, wherein the step of interconnecting comprises:

providing first and second discrete untreated glass members;

forming a first said inter-structure bond by connecting a first designated surface bonding region of said first untreated glass member to a second designated surface region of said second discrete untreated glass member by way of an intervening glass bonding member, whereby said first inter-structure bond includes said glass bonding member, a first weakened glass portion disposed in said first untreated glass member adjacent to said first designated surface region, and a second weakened glass portion disposed in said second untreated glass member adjacent to said second designated surface region; and

subjecting exposed portions of said first and second discrete untreated glass members to an ion-exchange treatment such that said first and second untreated glass members are converted into said first and second glass members connected by said first inter-structure bond.

15. The method of claim 14,

wherein providing said first and second discrete untreated glass members comprises providing glass materials having the same or similar coefficients of thermal expansion;

and

wherein forming said first inter-structure bond comprises utilizing a high temperature glass bonding technique.

16. The method of claim 14, wherein said connecting comprises forming said intervening glass bonding member using a high-temperature glass frit.

17. The method of claim 14, further comprising forming channels in exposed surface portions of said first and second discrete untreated glass members before said subjecting exposed portions of said first and second discrete untreated glass members to said ion-exchange treatment.

18. A method for producing a frangible structure in which propagating fracture forces are transferable in only one direction between first and second glass members, the method comprising:

generating strengthened glass portions in said first and second glass members, and a weaker member region in said second glass member;

interconnecting said first and second glass members such that a bonding member is directly connected between said weaker member region of said second glass member and said strengthened glass portion of said first glass member; and

mounting a trigger mechanism onto said first glass member, said trigger mechanism being configured to generate initial propagating fracture forces in said first glass member, whereby said initial propagating fracture forces generated in said first glass member by said trigger mechanism are transferred by way of said bonding member and said weaker member region to said second glass member.

19. The method of claim 18,

wherein generating said weaker member region comprises generating one of a weakened glass portion and a weakened surface feature in said second glass member, and

wherein interconnecting said first and second glass members comprises disposing said bonding member over said one of said weakened glass portion and said weakened surface feature.

20. The method of claim 19, wherein generating said weakened surface feature comprises:

providing an untreated glass member;

subjecting all exposed surfaces of said untreated glass member to an ion-exchange treatment, whereby said untreated glass member is converted into said second glass member having said weakened glass portion located under said mask; and

forming said weakened surface feature by removing glass material from said weakened glass portion through said designated surface region.