ASA Color Lens
We Understand Light, Not Just Rubber
Asahi Rubber is not just a rubber supplier, and not just optical specialists.
We have the strengths of both, to create the right design–and bring that design to reality.
Asahi Rubber has decades of experience in optical engineering with an in-house team.
And with our core competency in rubber manufacturing, leveraging over a half century of experience with a broad array of rubber types, we know how to maximize the material potentials of silicone to produce parts from both liquid and millable polymers, using both injection and compression techniques.
Track Record (Select)
Automotive
- Headlight active matrix primary optics
- IR auxiliary light source for door mirror camera or driver monitoring
- IR transceiver signal send and capture optics
- Number plate illumination
- Puddle light design projection
UV
- Ink curing
- Additive manufacturing curing
- Non-destructive inspection
Other Lighting
- Street/area lighting
- Roadway signage
- Flashlights
- Mobile phone light Fresnel lens
- Luminaires
- Medical exam lighting
A Rubber Lens
In a broad comparison, silicone rubber occupies a middle ground in the three general types of optics materials, between thermoplastics and glass.
Specifics vary, but as optical performance improves and overall durability goes up, so does cost.
In comparison with other materials, silicone rubber is ideally suited to UV and IR applications, or visible light applications with demanding heat/UV/weathering requirements or a design incorporating fine details of lens geometry.
Silicone is typically not suitable for imaging applications.
| Material Comparison | Silicone | PMMA | PC | Glass |
|---|---|---|---|---|
| Avg. Visible Light Trans. (%) | 94 | 93 | 88~90 | 95 |
| Refractive Index | 1.42 | 1.49 | 1.58 | 1.52 |
| UV Resistance | 〇 | △ | ✖ | 〇 |
| Chemical Resistance | △ | ✖ | △ | 〇 |
| Service Temp Max (°C) | >150 | 90 | 120 | >200 |
| Yellowing | 〇 | ✖ | ✖ | 〇 |
| Fine Detail Transcription | 〇 | △ | ✖ | ✖ |
| Min. Molding Thickness | <0.5mm | 2mm | 2mm | – |
| Molding Draft Angle | <0° | 1°~2° | 1°~2° | – |
| Lightweight | 〇 | △ | △ | ✖ |
| Flexibility | 〇 | ✖ | ✖ | ✖ |
Transparency
Our standard polymer, ASR-A80MC, has transmittance well above 90% throughout the visible range.
ASR-A80MC excels in infrared and near-UV performance as well, especially as compared to thermoplastics.
Asahi Rubber has experience with many polymers from a wide array of suppliers; we are ready to work with your own selection where preferred.
Heat degradation is mostly trivial, with marginal losses in efficiency in the visible spectrum.
Performance improves in most of the UV range with heat exposure over time.
Durability
| ASR-A80MC | Test Type | Method (JEITA ED-4701) | Conditions | Period | Appearance | Change in Transmittance ⊿T (%) | Yellowing ⊿YI |
|---|---|---|---|---|---|---|---|
| 1 | Thermal Shock | 300, 307 | -40°C→120°C 15min→15min | 500 cycles | No cracks/defects | 0.32 | 1.09 |
| 2 | High Temp Storage | 200, 201 | Ta=150°C | 1000hr | No cracks/defects | 0.69 | 1.55 |
| 3 | High Temp & Humidity Storage | 100, 103 | Ta=85°C, RH=85% | 1000hr | No cracks/defects | 0.99 | 0.76 |
| 4 | Low Temp Storage | 200, 202 | Ta=-40°C | 1000hr | No cracks/defects | 0.45 | 0.06 |
| 5 | Solvent Resistance | 500, 501 | Solvent: IPA 20~25°C, 5min | 1 time | No cracks/defects | – | – |
| 6 | Drop Test | – | 1m drop onto 20mm steel plate | 5 times | No cracks/defects | – | – |
Transcription
Silicone has inherent advantages over glass and thermoplastics in fine-detail transcription.
Our extensive experience enables full exploitation of this potential, achieving geometries difficult or impossible in other materials.
This fine-detail transcription makes applications such as advanced active matrix headlights possible.
Thermosetting materials perform better in completely filling all fine details of a mold before curing, where thermoplastics tend to have difficulties achieving the same.
Glass can be worked into fine details to some extent, but it is difficult and costly.
Siloxane & Outgassing Concern
Silicone is well known as having the drawback of outgassing complications. Outgassing can foul other optics or electronics, and the mass loss can alter the optical characteristics of the outgassing part.
We have a proprietary processing that all but eliminates these concerns. An additional step after secondary vulcanization reduces residual D3-D20 volatile siloxanes by over 98%; D3-D10 volatile siloxanes are reduced by over 96%!
Our lenses are used in demanding watertight-sealed automotive headlight applications.