# US 11,906,476 B2 · Joining state detection film, joining state detection device, and joining state detection method

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- Number: US 11,906,476 B2
- Document ID: US11906476B2
- Status: Granted
- Kind: B2
- Application number: 17/258,424
- Filed: 2019-06-13
- Published: 2021-09-16
- Granted: 2024-02-20
- Earliest claimed: 2018-07-19
- Assignees: National Institute of Advanced Industrial Science and Technology
- Applicants: National Institute of Advanced Industrial Science and Technology
- Inventors: Nao Terasaki; Yuki Fujio
- Web page: https://patentgrep.com/patent/US11906476B2

## CPC

- G01N 3/068: {with optical indicating or recording means}
- C09K 11/64: containing aluminium
- G01L 1/00: Measuring force or stress, in general (measuring force due to impact G01L5/00)
- G01N 3/40: Investigating hardness or rebound hardness
- G01N 19/04: Measuring adhesive force between materials, e.g. of sealing tape, of coating
- B29C 65/022: {Particular heating or welding methods not otherwise provided for}
- B29C 65/48: using adhesives {, i.e. using supplementary joining material; solvent bonding}
- B29C 65/561: {using screw-threads being integral at least to one of the parts to be joined}
- B29C 65/60: Riveting {or staking}
- G01N 2203/0296: Welds
- G01N 2203/0641: using optical, X-ray, ultraviolet, infrared or similar detectors
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)

## Abstract

An object is to provide a joining state detection film, a joining state detection device, and a joining state detection method, capable of detecting a joining state of a joining portion of two members from the outside. [Solution]A film containing a mechanoluminescent substance is formed on a surface, on a side opposite to a joining surface, of at least one member of two members that are joined at joining parts each having the joining surface, and physical stimulation is applied thereto.

## Claims

### Claim 1

A joining state detection method for detecting a joining state of two members that are joined at joining parts each having a joining surface, the method comprising the steps of:
forming the joining state detection film containing a mechanoluminescent substance on a first surface of a first of the two joining parts, the first surface being opposite to the joining surface of the first joining part; and
physically stimulating the joining part such that light is emitted from a luminescent part of the joining state detection film and light is not emitted from a non-luminescent part of the joining state detection film and an area of the non-luminescent part indicates an area of the joining surface where the two members are not joined.

### Claim 2 (depends on 1)

The joining state detection method according to claim 1, wherein the mechanoluminescent substance contained in the joining state detection film is a substance represented by SrAl2O4 that is doped with Eu2+, a substance represented by SrAl2O4 that is doped with at least one of Eu2+, Ho3+, Dy2+, M1, M2, and M3 (M1, M2, and M3 are monovalent to trivalent different metal ions), or a substance represented by CaYAl3O7 that is doped with Eu2+.

### Claim 3 (depends on 1)

The joining state detection method according to claim 1, wherein the two members are joined using an adhesive, a rivet, a bolt and a nut, a screw, a clinching fastener, and swaging.

### Claim 4 (depends on 1)

The joining state detection method according to claim 1, wherein the two members are joined by static electricity, anodic bonding, or welding.

### Claim 5 (depends on 1)

The joining state detection method according to claim 1, wherein a joining strength between the two members is detected on a basis of an area ratio of the luminescent part to the joining surface.

### Claim 6 (depends on 1)

The joining state detection method according to claim 1, wherein the step of forming a joining state detection film further forms a joining state visualization film containing a mechanoluminescent substance on at least one of a side surface and an end surface of the joining part.