Have you ever asked this question? Is this OCA optical adhesive intended for straight-screen smartphones, or for foldable phones?
According to statistics from CINNO Research, foreign manufacturers of OCA materials account for approximately 80% of the global panel industry market share, while domestic manufacturers hold less than 20%. The mid-to-high-end market is almost entirely dominated by overseas giants such as 3M, Mitsubishi, Nitto Denko, Desa, LG, SKC, and SDI. Domestic OCA manufacturers have only achieved breakthroughs in the repair market, while their market share in the high-end segment remains significantly lower.
What truly poses challenges for SQE professionals is not the pace of domestic substitution, but rather the severe underestimation of performance differences among the same material grade across diverse application scenarios. For example, the elastic modulus of OCA for smartphone straight-screen devices is approximately 80 MPa at 100 °C, whereas automotive OCA requires ≥150 MPa; the birefringence coefficient Δn for conventional OCA is around 5×10⁻⁴, while automotive-grade OCA must meet a requirement of <3×10⁻⁴; also, OCA for foldable displays must withstand over 200,000 bending cycles, whereas OCA for straight-screen devices is hardly subjected to bending tests. These distinctions directly dictate what parameters IQC should measure and what criteria manufacturers should evaluate during factory audits.
OCA Optical Adhesive: Key Parameters Across 5 Scenarios
| parameter | Straight-screen (mid-range) | Foldable screen | vehicle | Tablet/Laptop | Smart wearables |
| Energy storage modulus (100 °C) | ~80MPa | 0.1-1MPa | ≥150MPa | ~80MPa | ~80MPa |
| birefringenceΔn | ~5×10⁻⁴ | ~5×10⁻⁴ | ＜3×10⁻⁴ | ~5×10⁻⁴ | ~5×10⁻⁴ |
| light transmittance | ≥90% | ≥90% | ≥99.5% | ≥90% | ≥90% |
| fog level | ≤1% | ≤0.5% | ≤0.8% | ≤0.8% | ≤1% |
| Bending life | discard | ≥200,000 times | discard | discard | discard |
| Hold strength (80 °C / 85 % RH) | ≥12h | ≥12h | ≥24h | ≥12h | ≥12h |
| Typical thickness | 100-300μm | 50-100μm | 100-300μm | 150-400μm | 25-100μm |
Figure 1: OCA optical adhesive energy storage modulus temperature spectrum (DMA) — The physical origins of differences in material systems
Category 1: Smartphone straight-edge OCA screens — the benchmark for fully laminated displays, though performance varies significantly across high, mid, and low-end tiers.
Straight-panel phone displays are a primary OCA optical adhesive application, yet a common mistake made by SQE teams is to treat straight-panel OCA as a single product category during review. Based on material systems, straight-panel OCA can be categorized into at least three tiers: high-end silicone, mid-range acrylic, and low-end rubber-based variants. The performance gap between these three tiers is even more pronounced than that observed across different application scenarios.
High-end silicone OCA (e.g., 3M and Mitsubishi high-end grades) features a Si–O bond energy of 438 kJ/mol, a temperature resistance range from –60 °C to +150 °C, a dielectric constant of <3, superior bubble-free performance, and low MURA risk. The trade-offs include a cost 30–50% higher than acrylic OCA, the presence of “oxygen-induced polymerization inhibition” characteristics, and increased challenges in UV curing processes. It is primarily used in flagship devices and for bonding curved screens.
Mid-range acrylic OCA (e.g., Mitsubishi Mid-range line, Vantone, JiRou Optoelectronics) is the mainstream choice in the market, accounting for over 70% of the market share. It offers low cost, simple processing, and excellent mass-production capabilities. Its limitations include a maximum temperature resistance of approximately 100 °C, as well as potential yellowing of the main chain under prolonged high-temperature or UV exposure; also, its curing shrinkage rate is higher than that of silicone, which increases the risk of MURA during the bonding of large-sized substrates.
Low-end rubber-based OCA (some products in the domestic remanufacturing market) exhibits a light transmittance of only 85–88%, haze of 2–3%, and unstable peel strength. If SQE personnel select suppliers based solely on price, they may easily mistake low-end materials for mid-range ones, leading to batch yellowing and bubble re-emergence.
In addition to the material system, the bonding method also determines the selection of OCA. Full bonding (full-area OCA bonding) is used in mid-to-high-end devices, while frame bonding (edge-adhesive bonding, with fixation only on the four edges) is commonly employed in mid-to-low-end devices. Full bonding OCA cannot be used in frame bonding scenarios, and vice versa.
Failure modes: For high-end silicone products, the primary failure mode is supply chain concentration risk (monopolization by 3M and Mitsubishi); for mid-range acrylic products, failures are primarily attributed to bubble rebound (Delay Bubble) and yellowing; for low-end rubber-based products, failures manifest as batch transmittance failing to meet specifications and rapid aging.
In the supply chain segment, JiRou Optoelectronics reported OCA optical adhesive business revenue of 158 million yuan in 2024, representing a year-on-year increase of 21.3%. The products of Fansait, Mitsubishi, and 3M can all meet customer requirements in the full-lamination of edge-to-edge displays. However, the high-end silicone OCA market remains firmly dominated by 3M, Mitsubishi, and Desa, while domestic manufacturers are virtually absent in this sector.
IQC inspection (differentiated by grade)
| Test Items | test method | criterion of acceptability | Corresponding failure mode |
| Transmittance / Opacity | 380–780 nm integrating sphere type | High-end: ≥99%/≤0.5%; Mid-range: ≥90%/≤1%; Low-end: ≥85%/≤2% | Differences in optical properties of material systems |
| 180° peel strength | Universal testing machine, 300 mm/min | High-end: ≥2.5 N/mm; Mid-range: ≥1.5 N/mm; Low-end: ≥1.0 N/mm | Adhesive bonding reliability |
| Thickness uniformity | 10-point measurement within a 5×5 cm area | High-end: ≤±1 μm; Mid-range: ≤±2 μm; Low-end: ≤±3 μm | Fit accuracy / MURA risk |
| appearance inspection | Cleanroom magnifying glass | High-end: zero defects; Mid-range/Low-end: no bubbles, impurities, or gel particles | Bubble rebound / Particle impurities |
| Release force of release film | Release force tester | For high-end grades, a difference ≥30% shall prevent erroneous peeling; for mid-and low-end grades, the light-to-heavy difference shall comply with process specifications. | Fit process compatibility |
| Environmental resistance | 85℃/85%RH 1000h | Turbidity increase ≤ 0.5%, no foaming | High-temperature and high-humidity aging |
| UVage | 340nm，0.71W/m²，500h | The yellowness value ΔYI ≤ 3 | Yellowing / main chain degradation |
Figure 2: OCA molecular weight distribution (GPC) — PDI is the key indicator for assessing material grade.
Supplier on-site audit (4 high-risk processes + on-site issue identification)
| production processes | Review Key Points | key index | Identify issues on-site |
| Synthesis of adhesive polymers | Formulation system validation (silicone/acrylic/rubber-based), molecular weight distribution control | Molecular weight distribution (PDI) ≤ 1.5 | Request the latest three batches of FTIR spectra: silicone should exhibit a Si-O peak at 1100 cm⁻¹, whereas acrylic acid should not exhibit this peak; dielectric constant spot checks: silicone <3, acrylic acid ~ 4, rubber-type> 4 |
| Cleanroom coating | The cleanliness class of the workshop and the coating method shall be compatible with the product specifications. | Cleanliness class ≥ Class 10,000 | Bring a particle counter into the workshop for 10 minutes of monitoring and compare the results with the supplier’s self-test report; in the absence of online thickness measurement equipment, coating precision is highly likely to be estimated empirically. |
| Curing Process | Silicone components are confirmed to cure thermally; acrylic components are confirmed to cure via UV curing. | Uniform crosslinking density, with a curing degree of CPK ≥ 1.33 | Request the provision of the curing temperature profiles for each batch (including timestamps and equipment IDs); do not provide PS screenshots; conduct spot checks to verify the consistency between production records and the temperature profiles. |
| Precision die-cutting | Mold wear management and electrostatic discharge control | Die-cutting dimensional accuracy: ±0.1 mm | Conduct spot checks on the edge burr height of die-cut samples (should be <0.02 mm); verify the die inventory records: dies that have exceeded their service life may lead to batch dimensional deviations and excess adhesive leakage. |
Category 2: Foldable OCA — Fold life is the critical threshold
Foldable displays are the most technically challenging OCA optical adhesive application. Key requirements include: maintaining optical and adhesive performance after over 200,000 bending cycles, with a bending radius ≤ 3 mm; and exhibiting no delamination or bubble formation after 300 thermal shock cycles between −40 °C and 80 °C. The elastic modulus at room temperature should be only 0.1–1 MPa, and the degradation rate of peel strength after bending should not exceed 20%.
Failure modes: crack in the bending region (micro-cracks induced by repeated bending, which propagate and subsequently reduce light transmittance); interlayer delamination (insufficient interfacial adhesion between the OCA and the CPI cover glass or polarizer); optical distortion at the crease (rainbow patterns caused by non-uniform OCA thickness or uneven modulus distribution).
In the realm of supply chains, Samsung SDI has developed the first OCA specifically designed for foldable smartphones, while domestically produced foldable OCA materials remain in the validation phase. Jinghua New Materials ‘foldable OCA has already been adopted by leading domestic smartphone manufacturers, and Lushan New Materials’ foldable flexible OCA is currently undergoing validation trials with BOE Technology Group and OPPO. Foldable OCA represents Samsung SDI’s unequivocal market leadership; therefore, it is recommended that domestic suppliers be required to provide pre-test data demonstrating at least 50,000 folding cycles as a market entry threshold.
Figure 3: Foldable OCA bending life degradation curve — coupled degradation of mechanical and optical performance
IQCcheckout
| Test Items | test method | criterion of acceptability | Corresponding failure mode |
| Bending life | R=3 mm, 180° bending; measure transmittance and peel strength every 50,000 cycles. | ≥200,000 times | Maintain optical and adhesive properties during bending. |
| Optical properties after bending | Measure transmittance and haze using a integrating sphere after every 50,000 bending cycles. | Transmittance attenuation ≤ 5%, haze increase ≤ 0.5% | Transmittance decreases after bending |
| Delamination strength degradation rate after bending | Comparison of peel strength before and after 180° bending | Attenuation rate ≤ 20% | Adhesive performance decreases after bending. |
| Low-temperature bending | 50,000 flex cycles at-20 °C | flawless | Low-temperature environmental reliability |
| Optical inspection of the crease area | light microscopy | No rainbow patterns / no micro-cracks | Optical distortion at the crease |
| CPI/OCA interfacial adhesion | 90° peel test | Interface bonding strength ≥ 1.0 N/mm | Interlayer separation |
Supplier on-site audit (4 high-risk processes + on-site issue identification)
| production processes | Review Key Points | key index | Identify issues on-site |
| Flexible substrate formulation | Low-modulus acrylic or silicone-modified technology, DMA curve | Ambient temperature energy storage modulus: 0.1–1 MPa | Provide the DMA curve: for standard OCA, the room-temperature modulus must exceed 10 MPa; for folding-specific OCA, it must be <1 MPa; if the modulus does not meet these requirements, the material system may be counterfeit. |
| Low-stress coating | Tension control and online thickness monitoring | Coating precision ≤ ±1 μm | Verify that the online thickness measurement probe is physically present (and not merely a model); if no online monitoring is available, the thickness uniformity assessment is highly likely to yield false positives. |
| Bending Performance Verification | Bending test equipment, life-strength correlation database | Pre-test: ≥50,000 cycles | Conduct an on-site inspection of the bending testing machine settings: the angle must be 180° rather than 150°, and the radius must be 3 mm rather than 5 mm; provide the original test video or curve data. |
| Cleanliness and Contamination Control | Particle Counting and Foreign Object Traceability System | Zero tolerance for 50 μm particulate impurities | Impurities up to 50 μm are acceptable in standard OCA, but in folded OCA, such impurities can serve as the origin points of bending cracks; it is required to review the particle count records from the past three months and the foreign object traceability report. |
Category 3: In-vehicle OCA displays — vibration and high temperatures are silent killers.
In-vehicle displays are the fastest-growing OCA optical adhesive application. According to Omdia data, in 2023, in-vehicle touch displays with a screen size exceeding 10 inches accounted for 58.5% of the total market share. Key performance requirements include: a storage modulus at 100 °C ≥ 150 MPa (compared to 80 MPa for conventional OCA); compliance with the full-frequency vibration test per ISO 16750-3; retention capability at 80 °C / 85% RH for ≥ 24 hours; transmittance ≥ 99.5%, polarized light reflectance ≤ 0.8%, and birefringence Δn <3×10⁻⁴; as well as resistance to temperature cycling from –40 °C to 105 °C and prolonged UV exposure.
Failure modes: high-temperature bubble rebound (insufficient holding force), delamination at vibration edges, prolonged UV-induced yellowing and reduction in light transmittance, and interfacial stress cracking under temperature cycling.
In the supply chain landscape, automotive OCA components demand exceptionally high reliability, and customers exhibit minimal willingness to switch suppliers; consequently, established manufacturers such as 3M, Mitsubishi, and Desa hold an absolute dominant position. Domestic OCA manufacturers, however, remain virtually absent in the automotive sector, primarily due to a lack of long-term reliability databases—a critical bottleneck—given that overseas industry leaders possess over a decade of automotive application data, whereas domestic manufacturers lack at least five years of field validation experience.
Figure 4: In-vehicle OCA optical performance matrix — polarization reflectivity vs. birefringence: enabling instant identification of “counterfeits”
IQCcheckout
| Test Items | test method | criterion of acceptability | Corresponding failure mode |
| Energy storage modulus temperature spectrum | DMA Testing – 40 °C to 150 °C | ≥150 MPa at 100 °C | mechanical behavior under high temperature |
| Polarized light reflectance | Polarization light analyzer with a 6500K standard light source | ≤0.8% | Glare control under bright lighting conditions |
| birefringence | Optical Birefringence Tester | Δn＜3×10⁻⁴ | Newton’s ring effect control |
| High-temperature and high-humidity retention capacity | Tested under conditions of 80 °C / 85 % RH | No displacement for ≥24 hours | High-temperature bubble rebound |
| Adhesion after vibration | Inspection after vibration testing per ISO 16750-3 | No edge delamination/bubbles | Edge debonding due to vibration |
| Transmittance after UV aging | Testing after prolonged UV exposure | Attenuation rate ≤ 3% | Long-term UV-induced yellowing |
Supplier on-site audit (4 high-risk processes + on-site issue identification)
| production processes | Review Key Points | key index | Identify issues on-site |
| High-temperature performance formulation | High-temperature, high-modulus acrylic or polyurethane modification technology | Provide full-temperature range DMA spectra | The modulus of standard OCA at 100 °C is approximately 80 MPa, whereas automotive-grade OCA must have a modulus of ≥150 MPa; the DMA curve must be provided, and the data points at 100 °C shall be verified on-site. |
| Optical-grade coating | Workshop cleanliness and online optical defect detection | Class 1,000 or Class 100 cleanliness | The optical requirements for in-vehicle OCA systems are extremely stringent; the coating workshop must meet Class 1,000 or Class 100 cleanliness standards, and a third-party cleanliness report must be provided—rather than self-assessed results. |
| Curved surface conforming process compatibility | Curved surfacebonding samples and optical distortion test data | Optical distortion compliance | Provide sample data for curved surface fitting and raw data from optical distortion testing; if no curved surface samples are available, it indicates that validation has not been performed. |
| Long-term reliability verification | High-temperature and high-humidity, and UV aging database | Database with ≥1000h | Provide continuous operation logs of the aging chamber (with timestamps); if the 1,000-hour test actually only includes extrapolated data from 500 hours, the test shall be immediately judged as failed. |
Category 4: OCA for tablets/laptops – Uniformity traps in medium-to-large sizes
For tablets and laptops, the OCA optical adhesive area on 10–17 inch screens is approximately four times that of mobile phones. Key requirements: thickness of 150–400 μm; compensation of the panel’s flatness error; haze ≤ 0.8%; edge peel strength must be at least 20% higher than that at the center to prevent edge lifting; overall panel thickness deviation at 20 sampling points must be ≤ ±1.5 μm (more stringent than the ±2 μm requirement for flat-panel displays).
Failure modes: uneven thickness leading to Newton’s rings; edge lifting (due to thermal expansion/contraction and stress concentration); difficulty in exhaust venting for medium-to-large sizes, making it challenging to remove central bubbles and resulting in a “wall effect.”
In the supply chain sector, medium-to-large size OCA represents one of the fastest-growing areas for domestic substitution. Since 2012, Huigu Chemical has focused on its OCA optical adhesive and optical film businesses, and its full-lamination OCA solutions have been successfully deployed in the production of medium-to-large size touch display panels. Similarly, Stick has also achieved breakthroughs in the medium-to-large size segment, becoming one of the few domestic manufacturers to secure high-end customer certifications for OCA and maintain stable supply capabilities.
Figure 5: Full-sheet thickness uniformity distribution of tablets/laptops (20 data points) — “Passing at the center with out-of-specification edges” is the most insidious fraudulent pattern.
IQCcheckout
| Test Items | test method | criterion of acceptability | Corresponding failure mode |
| Full-page thickness scanning | High-precision thickness gauge, ≥20 measurement points | Generate a thickness distribution map with a deviation ≤ ±1.5 μm | Non-uniform thickness / Newton’s rings |
| Edge peel strength | 180° debulking at the midpoints and corners of all four sides | More than 20% higher than the center | Edge curling |
| Exhaustive assessment | Standard panel simulation bonding | Record the bubble purge time and pressure. | Perimeter Effect / Central Bubble |
| optical homogeneity | Optical camera inspection after mounting onto standard glass | The full-coverage transmittance consistency deviation shall be ≤2%. | optical distortion |
| dimensional stability | 24 h at 85 °C / 85% RH | Dimensional variation rate ≤ 0.1% | Thermal expansion and contraction deformation |
Supplier on-site audit (4 high-risk processes + on-site issue identification)
| production processes | Review Key Points | key index | Identify issues on-site |
| Wide-area coating | Maximum width and width-direction coating thickness uniformity | Width ≥ 1 m, CPK ≥ 1.67 | Request online thickness measurement data from wide-format coating equipment; in the absence of online monitoring, the thickness uniformity across the entire sheet is highly likely to be falsely reported; conduct spot checks on CPK reports from the past three months. |
| Large-area die-cutting precision | Dimensional accuracy, right-angle accuracy | Within ±0.1 mm | Conduct on-site spot checks on die-cut samples: use a 2D measuring instrument to verify the four-side dimensions and right-angle accuracy; if the die inventory records are incomplete or have expired, accuracy cannot be guaranteed. |
| Edge processing technology | Edge finishing (coating / chamfering) | The edge peel strength meets the specified requirements. | Provide edge processing documentation and validation data; in the absence of edge reinforcement treatment, the risk of edge lifting is extremely high. |
| Packaging Protection | Packaging method and transportation vibration testing | Rigid blister box + moisture-proof bag | On-site unpacking inspection: verify whether a rigid blister box combined with a moisture-proof bag is used; if only a cardboard box combined with a PE bag is used, folding during transport may lead to batch optical defects. |
Category 5: Smart Wearable OCA — Process Limitations for Small-Sized Curved Surfaces
OCA optical adhesive in smartwatches and fitness bands covers screen sizes ranging from 1–3 inches, with a pronounced trend toward curved and flexible designs. Key requirements include: thickness of 25–100 μm to accommodate ultra-thin designs; curved bending radius ≤5 mm without cracking or delamination; waterproof performance up to 50 m (5ATM) pressure with sealed integrity, and a post-submersion peel strength degradation rate ≤15%; in certain application scenarios, biocompatibility is required (skin sensitization rate <0.01%).
Failure modes: Curved-area blistering (uneven thickness due to curvature variation leading to stress concentration); edge adhesive overflow (insufficient die-cutting precision or excessive bonding pressure); perspiration corrosion (long-term exposure of OCA edges to salt-containing human sweat, resulting in delamination or yellowing).
In terms of the supply chain, the smart wearable OCA market is highly fragmented: the high-end segment is dominated by 3M and Mitsubishi, while the share of domestic manufacturers in the mid-to-low-end segments has been steadily increasing. Due to the low brand concentration in the wearable device sector—characterized by a large number of white-label manufacturers—the quality of the supply chain varies significantly, making this category prone to being overlooked during SQE audits.
Figure 6: Comparison of OCA smart wearable devices’ performance in extreme environments—waterproofing and sweat corrosion are key tests for differentiating material grades.
IQCcheckout
| Test Items | test method | criterion of acceptability | Corresponding failure mode |
| Curved surface conformability | Simulated fit using a standard curved fixture with R=5 mm | The bubble rate in the curved region is ≤1%, and the optical uniformity meets the specified requirements. | Curved surface bubble adhesion |
| Edge accuracy | Inspect all four sides of the 2D measuring instrument. | Dimensional accuracy: ±0.05 mm; right-angle accuracy: meets specifications | Edge glue overflow |
| water resistance | 1-hour simulation in a 50-meter-deep pressure chamber | No edge delamination/bubbles | Failure of waterproof sealing |
| Sweat tolerance | Artificial sweat, pH 4.5–6.5, immersed in 0.5% NaCl solution for 48 h at the edges | Peel strength degradation rate ≤ 15% | Sweat corrosion |
| appearance inspection | Inspection under a standard light source | Zero Defects | Edge glue overflow / uneven edges / wrinkles |
| biocompatibility | ISO 10993 Skin Sensitization Test | Sensitization rate <0.01% | Skin contact safety |
Supplier on-site audit (4 high-risk processes + on-site issue identification)
| production processes | Review Key Points | key index | Identify issues on-site |
| Small-size precision die-cutting | Cutting edge precision and mold service life management | Cutting edge precision ≤ 0.02 mm | Conduct on-site spot checks on the edges of die-cut samples: if the burr height exceeds 0.02 mm, the die may be worn but not yet replaced; verify the die inventory records and replacement logs. |
| Curved surface conforming process compatibility | Curved surfacebonding sample; thickness distribution in curved regions | Uniform thickness distribution | Provide sample data of curved surface conformability and raw thickness distribution data of the curved surface region; if no curved surface samples are available, state that process validation has not been performed. |
| Edge sealing design | Edge reinforcement scheme (adhesive application / sealing ring) | Sealing performance meets the requirements | A edge-sealing design validation report must be provided; for products without edge reinforcement, a waterproof rating of 50 meters is merely a hollow claim. |
| Biocompatibility Management | Traceability of medical-grade wearable materials | ISO 10993 Test Report | An ISO 10993 biocompatibility test report shall be provided to verify whether the test parameters cover skin sensitization; if the report has expired or the testing institution lacks the requisite qualifications, the product shall be directly deemed non-compliant. |
Cross-Scenario Comparison: Differences Among Five OCA Types and Common Detection Pitfalls
Flat screens are the OCA optical adhesive baseline, yet their internal three-stage performance characteristics vary significantly: foldable screens face the highest requirements for bending durability, the most stringent adaptability to automotive environments, the greatest challenges in achieving uniformity across tablets and laptops, and the most rigorous demands on manufacturing craftsmanship for small-sized curved displays in smart wearables.
The four most common pitfalls in SQE testing are as follows: first, applying low-end rubber-based standards to high-end silicone suppliers while overlooking differences in material systems; second, using flat-panel display standards to evaluate OCA for foldable displays while neglecting bending life; third, failing to consider the high-temperature storage modulus and polarized light reflectivity of automotive OCA; fourth, employing ±2 μm flat-panel or laptop standards to assess OCA for smart wearables while disregarding the edge precision of small-sized curved displays.
Another common mistake is confusing OCA types with curing methods. Foldable displays typically require dual curing—thermal curing combined with UV curing; automotive applications predominantly use thermal curing; while smart wearable devices mostly employ UV curing. IQC recommends verifying that the curing method is appropriate for the specific application scenario, rather than focusing solely on final performance metrics. Another pitfall during supplier audits is overemphasizing final performance tests while neglecting process control. It is advisable to require suppliers to provide CPK data for critical processes: CPK for adhesive molecular weight distribution ≥1.33, CPK for coating thickness ≥1.67, and CPK for degree of curing ≥1.33.
SQE Action Plan
| scene | Key Inspection Points for IQC | Key Focus Areas for Supplier Audits | top risk |
| Flat screen (high-end silicone) | Transmittance ≥ 99%, haze ≤ 0.5%, peel strength ≥ 2.5 N/mm, thickness ≤ ±1 μm | Traceability of silicone raw materials, coating cleanliness ≥ Class 1,000, thermal curing CPK | Uniform supply chain and uneven oxygen-induced polymerization curing |
| Flat screen (mid-range acrylic) | Transmittance ≥ 90%/ haze ≤ 1%, peel strength ≥ 1.5 N/mm, thickness ≤ ±2 μm | Acrylic formulation stability, coating cleanliness ≥ Class 10,000, UV-curable CPK | Bubble rebound and yellowing |
| Straight-screen (low-end rubber type) | Transmittance ≥ 85%, haze ≤ 2%, peel strength ≥ 1.0 N/mm, thickness ≤ ±3 μm | Raw material grade, coating environment cleanliness, die-cutting precision | Batch transmittance fails to meet specifications; rapid aging |
| Foldable screen | Bend life: 200,000 cycles; optical and peel performance after bending; low-temperature bending | Flexible substrate formulation, low-stress coating precision, bending database | Micro-cracks in the bending zone, interlaminar delamination |
| In-vehicle display | Energy storage modulus temperature spectrum, polarized light reflectivity, and high-temperature and high-humidity retention properties | High-temperature performance formulation, optical-grade coating cleanliness, and reliability database | Edge delamination under vibration; bubble rebound at high temperatures |
| Tablet/Laptop | Full-page thickness scan, edge peel strength, and gas permeability | Wide-width coating capability, large-area die-cutting precision, and edge finishing processes | Newton’s rings, edge lifting |
| Smart wearables | Surface conformity, edge precision, waterproofness, sweat resistance | Small-format precision die-cutting, curved surface lamination, and edge sealing design | Curved surface bubbles, sweat corrosion |
An OCA optical adhesive evaluation criterion: if they cannot even produce an FTIR spectrum, it is highly unlikely that the material is silicone. If their coating workshop lacks even an in-line thickness measurement device, the thickness uniformity data is likely fabricated.
epilogue
OCA optical adhesive spans 5 application scenarios, 3 sub-categories for flat-panel displays, 8 parameter systems, and 8 factory evaluation logics. The value of OCA optical adhesive lies not in its transparency, but in whether it aligns with the actual mechanical stresses of end-use scenarios. The value of SQE is not about establishing a CAR, but about preventing issues from arising in the first place—and the first step toward this goal is to recognize that the same material code may, across different scenarios, consist of entirely different materials.
Disclaimer: The data in this document is derived from publicly available industry reports and corporate announcements; test conditions may vary, and specific parameters shall be subject to the actual supplier datasheets.
Everything covered here draws on the UV curing adhesive range JOME manufactures in house. Engineers comparing notes with Mobile Phone Adhesive Cross Module Factory Inspection can move between the two guides; the the full JOME bonding solutions line frames the range and the send drawings to the JOME team takes it from there.