home > blog > Transparent Circuit Boards - Clear Flexible PCBs and Ceramic PCBs

Transparent Circuit Boards - Clear Flexible PCBs and Ceramic PCBs

Star level: icon_staricon_staricon_staricon_staricon_star

Thur, Sept 23, 2021

Have you ever seen transparent circuit boards? Transparent circuit boards are important in optical fields. You can see through transparent PCBs, and even the conductive traces and components embedded in the circuit boards can be transparent. Most transparent circuit boards are flexible PCBs using PET film, and some transparent PCBs are ceramic PCBs. PCBONLINE, an advanced PCB manufacturer, provides one-stop transparent circuit board manufacturing. In this post, we will introduce clear flexible PCBs and transparent ceramic circuit boards to you.

Transparent Flexible Circuit Boards

Transparent flexible PCBs are FPCs using PET thin film. PET materials can be transparent, white, light blue, light green, etc. Clear FPCs are different from normally seen flexible PCBs only because of the transparent PET materials.

In some transparent flexible PCBs, only the substrate is transparent, and the conductive traces and pads are visible and not transparent.

clear fpc of transparent circuit boards

Some transparent flexible PCBs, including the conductive traces, are fully clear. An innovative manufacturing method is used -- the circuit is clamped between two transparent materials to protect it and make it invisible from the outside. And PCBONLINE can produce fully transparent FPCs.

Advantages of transparent flexible PCBs:

  • A wide range of optical features.
  • Bendable, foldable, twistable, and arbitrarily movable and flexible in three-dimensional space.
  • The accurateness of the FPC manufacturing reaches the micron or nano level.
  • FPCs save about 90% product weight compare with rigid PCBs of the same volume.
  • Achieve lightweight, miniaturization, and thinning of the products.

Applications of transparent flexible PCBs:

FPCs are widely used in automatic control, instrument panels, ABS systems, cameras, mobile phones, calculators, medical devices, and wherever connections are required in a close-packed space. Besides, fully transparent flexible PCBs can be used in smart contact lenses, flexible transparent electronic devices, and electronic skins.

You would like to have transparent flexible PCBs manufactured and assembled? PCBONLINE provides one-stop transparent FPC manufacturing and assembly, including prototyping and batch production.

Technical specifications:

  • transparency up to 94.36 %
  • 1 to 10 layer transparent circuit boards
  • surface finish: ENIG, OSP, ENEPIG, immersion tin
  • min laser blind hole: 0.075 mm
  • min mechanical drilling hole: 0.1 mm
  • min line width: 0.035 mm
  • min line spacing: 0.035 mm
  • max blind hole aspect ratio: 0.8
  • min interlayer alignment: ±0.05mm
  • heat resistance for soldering: 260 °C × 5 sec.
  • adhesive strength: 490 N/m
  • glass transition temperature: 300 °C
  • operating temperature: -25 °C to +75°C

Transparent Ceramic Circuit Boards

alumina PCB of transparent circuit boards

Transparent ceramic PCBs substrates can be alumina (aluminum oxide), magnesium oxide, yttrium oxide, Aron, and Al-Mg spinel. PCBONLINE can produce alumina transparent PCBs.

The alumina we use is at the nano level and has a nano-blue phase. Nano aluminum oxide is added to the resin water-based liquids to 5% to 10%, which increases the resin hardness to 6H to 8H. The nano alumina liquid used to manufacture transparent alumina PCBs can be oily or water-based.

Transparent ceramic PCBs have transparent substrates and a glass-based solder mask, but the conductive part is not transparent. The transparent ceramic PCBs manufactured by PCBONLINE have 75% to 85% transparency, and not to decrease the transparency, we recommend the solder mask covering only on the conductive part (traces and pads). Solution experts at PCBONLINE will provide one-on-one engineering support to assist you with the best practices.

Advantages of transparent ceramic circuit boards:

  • A wide range of optical features.
  • 2000+℃ high-temperature resistance (the glass transition temperature of thorium oxide-yttrium oxide circuit boards reach 3100℃).
  • Good thermal conductivity (26+W/mK).
  • Stable and small coefficient of thermal expansion.
  • No water absorption and good electrical insulation.

Applications of transparent ceramic circuit boards:

    • High-pressure sodium lamps (HPS, high-efficient electric light source of the longest life span),
    • High power LED,
    • Optical sensors,
    • Infrared windows used in aircraft, missiles, etc.

Technical specifications of transparent alumina circuit boards:

  • transparency: 75% to 85%
  • thermal conductivity: 24W/mK to 31.4W/mK
  • substrate thickness: 0.12mm to 30mm
  • operating temperature: up to 1400℃ to 1600℃

Know More about Transparent Circuit Boards Manufacturer

PCBONLINE, founded in 1999, provides transparent circuit board manufacturing and assembly to customers around the world. Industries we serve include automotive, defense, industrial, medical, communications, and consumer electronics.

PCBONLINE transparent circuit board manufacturer

Ordering transparent circuit boards from PCBONLINE, you will enjoy these benefits:

  • Solution experts at PCBONLINE provide free DFM, DFT, and DFX for your transparent circuit boards.
  • PCBONLINE always manages to reduce your costs with the latest technologies and manufacturing optimization.
  • You can track the whole manufacturing process online through our customer system, and all materials and electrical parts are traceable.
  • We can conduct four-terminal sensing to ensure the best electrical performance of your transparent circuit boards.
  • Besides transparent circuit boards, you can also buy rigid-flex PCBs, HDI PCBs, high-frequency PCBs, aluminum PCBs, normal FPCs, and ceramic PCBs from PCBONLINE.

PCBONLINE offers $100 off coupons for online purchases. If your transparent circuit board order amount is $5000 or more, we will offer you free complete PCBA samples, functional testing, and discounts. Now register to get an instant quote or purchase online.


Currently, only FPCs and ceramic PCBs can be transparent circuit boards. Clear FPCs can be fully transparent, or only the substrate is transparent. Ceramic transparent circuit boards are not fully clear, and a solder mask is advised to cover only the conductive part. If you have any questions with transparent circuit boards, or you want to have transparent circuit boards manufactured and assembled, welcome to contact PCBONLINE.