Transparent Heaters

Shape Optics, has pioneered the use of I.T.O. and I.M.ITO ™ with BBAR coatings for efficient and high performance Transparent Heaters for avionics, locomotives, flat panel displays, ships and cameras. The heating uniformity and burned out is controlled by very low resistive bus bar material with low contact resistance.

The heaters can be designed for wide resistance from 300 – 5 ohms and voltages (115, 28, 24, 12 volt). The heater with I.T.O. or I.M.ITO ™ has been tested up to 10 watts per square inch. Usually a much lower heat is used for LCD display applications. The bonded heaters require less power than stand alone, typically 1/3. The I.T.O. and I.M.ITO ™ coatings are extremely reliable and stable for continuous operations. The typical visible transparency for I.T.O. is ≥ 80% avg., and IMITO™ is ≥ 92% average.

Transparent Heaters heaters are I.M.ITO™ to epoxy or air, for stand alone or lamination versions. The heater designed for 0.1 Watt/Sq. Inch – 5 Watt/Sq. Inch.

Shape Optics is also a leading Transparent Heaters manufacturer for sapphire and silicon substrates using accumulation of metal and/or oxide in a grid pattern, which can be powered up to 20 Watts/Sq. Inch, with transmission up to 95%, in the ranges of 0.8µm – 6.5 µm. An ideal choice for NIR and IR applications.

Transparent heaters are essential to use for challenging environments for cameras, LCD’s & electro-optical devices below -10ºC. The application in Avionics, cameras, LCD’s & locomotives require heaters so they can operate in cold and severe climates. Applying a heater is the simplest solution. The transparent heater is usually made by only I.T.O. or I.M.I.T.O. ™ with higher transmittance. The resistance of the heater determines the rate of heat required and power utilization. The lower the resistance, it requires higher power and higher rates of heating.

Substrate Specifications

Glass

Corning Eagle XG, Eagle 2000, Borafloat, Standard float (soda-lime)

Tempered Glass

Chemical or Heat Tempered

Thicknesses:

0.01″ (0.25 mm) to 0.5″ (12.7 mm) standard.

(For others, consult SOT)
70 µm & 100 µm On Special Request

Process:
Ion Beam Sputtering (Superior Process)

Applications:
Commercial Displays, Avionics and Military Displays

Coating Non-Uniformity
± 2.5% across full sheet

Product Dimensions

Plain Version:

All from 1/2″ sq. or round, to 24” x 24″ (610 mm x 610 mm)

Patterned:

Sizes from 1/2″ sq. to 14” x 18″ (355 mm x 457 mm)

Many Custom Variations Available:
(consult TFD)

Circular domes
Curved plates
Wide variations on voltage and power are possible

Tolerances for sizing:± 0.002″ (0.05 mm)

Surface Quality:

  • Defects: < 5 micron on large substrates
  • Imbedded Particle < 2 micron
  • Surface Roughness: < 20 Å RMS, for each side
  • Inspection Quality:
    80/50 to 20/10 (5K Lux)
    Thermal Imaging

Durability:
Abrasion: 200 strokes @ 10Kgm (Mil C-675)
Adhesion: Snap Test (Mil M-13508)
Solubility: > 24 hours in Sodium Chloride, Fog and Solution (Mil C-675)
Temperature: > 12 hours @ -55 to 350°C

Packaging:
Class 100, or as required.

Optical Characteristics (See Curves)

Heater Types:

Plain I.T.O.

I.M.ITO™

I.M.ITO™

Grid / Patterned

Transmissions: *

75 – 85%

85 94%

* 90 – 98%

IR 90%

Vs. Wavelength:

400-700nm

400-700nm

400-700nm

1 – 10 µm

Resistivity, nominal (ohms/sq.)

2 to 350

2 to 350

2 to 350

5 to 50

* ITO Thickness Dependent

Resist Equation
For the final manufacture of a heater, the resistance for the heater (ohms) is converted to resistivity (*ohms/sq.)
This value is a function of the length of the heater (L) and the width (W) as it relates to the total resistance. L is the size between bus bars.

p(Resistivity) Ohms S/SQ. = R (Resistance) Total in Ohms x (B + L)
The Heater consumes power per Ohms Law: P= E2 + R

Other Material Resistivity Table

 

Resistivity
(Ohm – Cmm)

Thickness Å

TCR Thermal Coefficient
of Resistivity

General Nature

   

ppm@25˚C

 

ITO Transparent

1.5×10 -4

1500 Å

1500+200

Transparent

SiOiCr

7.2×10 -4

1500 Å

100+25

Black

Inconel

4.5×10 -4

1500 Å

*150+25

Metal (grid)

NiCr

3.5×10 -4

1500 Å

*300+50

Metal (grid)

TaN

4.5×10 -4

1500 Å

*100+50

Ceramic

AI

4.6×10 -6

1500 Å

450+50

Metal (grid)

Others Available Upon Request

 BusBar Coatings

SOT offers several solutions of low profile, solid state and silver bus bars completely compatible for all solvents and pull tests of 8K gram/sq in.

A. Metalized Busbar. Cr / Ni / Au Solderable
B. Silver Epoxy
C. Copper Tape

A diagram of bus bar structure

Description automatically generated

The heaters can be designed for wide resistance from 300 – 5 ohms and voltages (115, 28, 24, 12 volt). The heater with I.T.O. or I.M.ITO ™ has been tested up to 10 watts per square inch. Usually a much lower heat is used for LCD display applications. The bonded heaters require less power than stand alone, typically 1/3. The I.T.O. and I.M.ITO ™ coatings are extremely reliable and stable for continuous operations. The typical visible transparency for I.T.O. is ≥ 80% avg., and IMITO™ is ≥ 92% average.

The patterned heaters are commonly used for uniquely higher or lower powers, ≥ 10 watts/sq. inch. TFD can design patterned for various shapes, & sizes while maintaining uniform heating.

The patterned heaters are also very desirable for Infra-Red (IR) applications for wavelengths of 1.0 µm – 12 µm.

A graph of a temperature

Description automatically generated
A graph of a heater

Description automatically generated

The patterned heaters are commonly used for uniquely higher or lower powers, ≥ 10 watts/sq. inch. SOT can design patterned for various shapes, & sizes while maintaining uniform heating.

The patterned heaters are also very desirable for Infra-Red (IR) applications for wavelengths of 1.0 µm – 12 µm.

A screenshot of a computer screen

Description automatically generated

Connection: Bus bar to heating surface.

The contact resistance from the bus bar to the heating surface, I.T.O., I.M.I.T.O. ™, or NiCr must have ≤ 0.1 ohm.  The other rule of thumb is to have individual bus bar resistance to be ≤ 5% of the total resistance of the heater.  The bus bar materials are:

A. Silver Epoxy          B. Soldered Metallization          C. Silver Frit Material

The Silver Epoxy is inexpensive and decays in 2 – 3 years. The Silver Frit Material has to be fired at ≥ 350°C which deforms glass flatness and this process contaminates the surface. The Metalized Bus bar, such as Cr/Ni/Au, is a solid state process and works extremely well with Soldered bus bar heaters. This is a highly recommended process.

Power Calculation: 

Below a Temperature Rise curve is provided that gives the relationship of time versus power of the heater with thickness 0.040”. There are different ways to apply heater glass with displays: A. Stand alone. B. Laminated. The standalone are typically applied in the back of the displays and have air gaps, 0.008” – 0.020”, which makes it a poor heating system. For low heat requirements it’s plenty. For fast rise temperature the heater glass should be bonded for optimum avionics applications.

Mounting heater glass on the front (viewing side) of the display is not recommended as heat loss to air could be as high as 50% of the total heat.

A thermistor or I.T.O. / Thermal coefficient of resistance (TCR) is commonly used to control temperature.

If higher temperatures are used to quickly heat the display, you must reduce that heat level once at operating temperature. Additionally, it is not recommended to operate heaters above a 20°C ambient temperature.

Resistivity Table

 

Resistivity

Thickness Å

TCR/PPM

General Nature

I.T.O.

1.5×10 -4

1500 Å

1500 ±250

Transparent

Sn02

3.5 x 10 -4

1500 Å

1500 ±100

Transparent

NiCr

3.5 x 10 -4

1500 Å

300 ±50

Opaque

TaN

4.5×10 -4

1500 Å

150 ±50

Opaque

Inconel

4.5×10 -4

1500 Å

225 ±50

Opaque

Si0iCr

7.2 x 10 -4

1500 Å

150 ±50

Opaque

 BusBar Materials as Follows

 

Power Recommendation

Application

1. Silver Epoxy

≤1.5 watt/sq inch

Commercial Heaters

2. Silver Epoxy with Copper Strip

≤2.0 watt/sq inch

Commercial/Industrial

3. Sputtered Cr/Ni/Au

1 – 10 watt/sq inch

Avionics, Ruggedized

4. Silver Frit

2.5 – 5 watt/sq inch

Commercial/ Industrial

A diagram of a temperature

Description automatically generated

Transparent Heaters

Shape Optics, has pioneered the use of I.T.O. and I.M.ITO ™ with BBAR coatings for efficient and high performance Transparent Heaters for avionics, locomotives, flat panel displays, ships and cameras. The heating uniformity and burned out is controlled by very low resistive bus bar material with low contact resistance.

The heaters can be designed for wide resistance from 300 – 5 ohms and voltages (115, 28, 24, 12 volt). The heater with I.T.O. or I.M.ITO ™ has been tested up to 10 watts per square inch. Usually a much lower heat is used for LCD display applications. The bonded heaters require less power than stand alone, typically 1/3. The I.T.O. and I.M.ITO ™ coatings are extremely reliable and stable for continuous operations. The typical visible transparency for I.T.O. is ≥ 80% avg., and IMITO™ is ≥ 92% average.

Transparent Heaters heaters are I.M.ITO™ to epoxy or air, for stand alone or lamination versions. The heater designed for 0.1 Watt/Sq. Inch – 5 Watt/Sq. Inch.

Shape Optics is also a leading Transparent Heaters manufacturer for sapphire and silicon substrates using accumulation of metal and/or oxide in a grid pattern, which can be powered up to 20 Watts/Sq. Inch, with transmission up to 95%, in the ranges of 0.8µm – 6.5 µm. An ideal choice for NIR and IR applications.

Transparent heaters are essential to use for challenging environments for cameras, LCD’s & electro-optical devices below -10ºC. The application in Avionics, cameras, LCD’s & locomotives require heaters so they can operate in cold and severe climates. Applying a heater is the simplest solution. The transparent heater is usually made by only I.T.O. or I.M.I.T.O. ™ with higher transmittance. The resistance of the heater determines the rate of heat required and power utilization. The lower the resistance, it requires higher power and higher rates of heating.

Substrate Specifications

Glass

Corning Eagle XG, Eagle 2000, Borafloat, Standard float (soda-lime)

Tempered Glass

Chemical or Heat Tempered

Thicknesses:

0.01″ (0.25 mm) to 0.5″ (12.7 mm) standard.

(For others, consult SOT)
70 µm & 100 µm On Special Request

Process:
Ion Beam Sputtering (Superior Process)

Applications:
Commercial Displays, Avionics and Military Displays

Coating Non-Uniformity
± 2.5% across full sheet

Product Dimensions

Plain Version:

All from 1/2″ sq. or round, to 24” x 24″ (610 mm x 610 mm)

Patterned:

Sizes from 1/2″ sq. to 14” x 18″ (355 mm x 457 mm)

Many Custom Variations Available:
(consult TFD)

Circular domes
Curved plates
Wide variations on voltage and power are possible

Tolerances for sizing:± 0.002″ (0.05 mm)

Surface Quality:

  • Defects: < 5 micron on large substrates
  • Imbedded Particle < 2 micron
  • Surface Roughness: < 20 Å RMS, for each side
  • Inspection Quality:
    80/50 to 20/10 (5K Lux)
    Thermal Imaging

Durability:
Abrasion: 200 strokes @ 10Kgm (Mil C-675)
Adhesion: Snap Test (Mil M-13508)
Solubility: > 24 hours in Sodium Chloride, Fog and Solution (Mil C-675)
Temperature: > 12 hours @ -55 to 350°C

Packaging:
Class 100, or as required.

Optical Characteristics (See Curves)

Heater Types:

Plain I.T.O.

I.M.ITO™

I.M.ITO™

Grid / Patterned

Transmissions: *

75 – 85%

85 94%

* 90 – 98%

IR 90%

Vs. Wavelength:

400-700nm

400-700nm

400-700nm

1 – 10 µm

Resistivity, nominal (ohms/sq.)

2 to 350

2 to 350

2 to 350

5 to 50

* ITO Thickness Dependent

Resist Equation
For the final manufacture of a heater, the resistance for the heater (ohms) is converted to resistivity (*ohms/sq.)
This value is a function of the length of the heater (L) and the width (W) as it relates to the total resistance. L is the size between bus bars.

p(Resistivity) Ohms S/SQ. = R (Resistance) Total in Ohms x (B + L)
The Heater consumes power per Ohms Law: P= E2 + R

Other Material Resistivity Table

 

Resistivity
(Ohm – Cmm)

Thickness Å

TCR Thermal Coefficient
of Resistivity

General Nature

   

ppm@25˚C

 

ITO Transparent

1.5×10 -4

1500 Å

1500+200

Transparent

SiOiCr

7.2×10 -4

1500 Å

100+25

Black

Inconel

4.5×10 -4

1500 Å

*150+25

Metal (grid)

NiCr

3.5×10 -4

1500 Å

*300+50

Metal (grid)

TaN

4.5×10 -4

1500 Å

*100+50

Ceramic

AI

4.6×10 -6

1500 Å

450+50

Metal (grid)

Others Available Upon Request

 BusBar Coatings

SOT offers several solutions of low profile, solid state and silver bus bars completely compatible for all solvents and pull tests of 8K gram/sq in.

A. Metalized Busbar. Cr / Ni / Au Solderable
B. Silver Epoxy
C. Copper Tape

A diagram of bus bar structure

Description automatically generated

The heaters can be designed for wide resistance from 300 – 5 ohms and voltages (115, 28, 24, 12 volt). The heater with I.T.O. or I.M.ITO ™ has been tested up to 10 watts per square inch. Usually a much lower heat is used for LCD display applications. The bonded heaters require less power than stand alone, typically 1/3. The I.T.O. and I.M.ITO ™ coatings are extremely reliable and stable for continuous operations. The typical visible transparency for I.T.O. is ≥ 80% avg., and IMITO™ is ≥ 92% average.

The patterned heaters are commonly used for uniquely higher or lower powers, ≥ 10 watts/sq. inch. TFD can design patterned for various shapes, & sizes while maintaining uniform heating.

The patterned heaters are also very desirable for Infra-Red (IR) applications for wavelengths of 1.0 µm – 12 µm.

A graph of a temperature

Description automatically generated
A graph of a heater

Description automatically generated

The patterned heaters are commonly used for uniquely higher or lower powers, ≥ 10 watts/sq. inch. SOT can design patterned for various shapes, & sizes while maintaining uniform heating.

The patterned heaters are also very desirable for Infra-Red (IR) applications for wavelengths of 1.0 µm – 12 µm.

A screenshot of a computer screen

Description automatically generated

Connection: Bus bar to heating surface.

The contact resistance from the bus bar to the heating surface, I.T.O., I.M.I.T.O. ™, or NiCr must have ≤ 0.1 ohm.  The other rule of thumb is to have individual bus bar resistance to be ≤ 5% of the total resistance of the heater.  The bus bar materials are:

A. Silver Epoxy          B. Soldered Metallization          C. Silver Frit Material

The Silver Epoxy is inexpensive and decays in 2 – 3 years. The Silver Frit Material has to be fired at ≥ 350°C which deforms glass flatness and this process contaminates the surface. The Metalized Bus bar, such as Cr/Ni/Au, is a solid state process and works extremely well with Soldered bus bar heaters. This is a highly recommended process.

Power Calculation: 

Below a Temperature Rise curve is provided that gives the relationship of time versus power of the heater with thickness 0.040”. There are different ways to apply heater glass with displays: A. Stand alone. B. Laminated. The standalone are typically applied in the back of the displays and have air gaps, 0.008” – 0.020”, which makes it a poor heating system. For low heat requirements it’s plenty. For fast rise temperature the heater glass should be bonded for optimum avionics applications.

Mounting heater glass on the front (viewing side) of the display is not recommended as heat loss to air could be as high as 50% of the total heat.

A thermistor or I.T.O. / Thermal coefficient of resistance (TCR) is commonly used to control temperature.

If higher temperatures are used to quickly heat the display, you must reduce that heat level once at operating temperature. Additionally, it is not recommended to operate heaters above a 20°C ambient temperature.

Resistivity Table

 

Resistivity

Thickness Å

TCR/PPM

General Nature

I.T.O.

1.5×10 -4

1500 Å

1500 ±250

Transparent

Sn02

3.5 x 10 -4

1500 Å

1500 ±100

Transparent

NiCr

3.5 x 10 -4

1500 Å

300 ±50

Opaque

TaN

4.5×10 -4

1500 Å

150 ±50

Opaque

Inconel

4.5×10 -4

1500 Å

225 ±50

Opaque

Si0iCr

7.2 x 10 -4

1500 Å

150 ±50

Opaque

 BusBar Materials as Follows

 

Power Recommendation

Application

1. Silver Epoxy

≤1.5 watt/sq inch

Commercial Heaters

2. Silver Epoxy with Copper Strip

≤2.0 watt/sq inch

Commercial/Industrial

3. Sputtered Cr/Ni/Au

1 – 10 watt/sq inch

Avionics, Ruggedized

4. Silver Frit

2.5 – 5 watt/sq inch

Commercial/ Industrial

A diagram of a temperature

Description automatically generated

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    The material used in this knowledge sharing, is only for research, academic, non-profit educational or personal use, the blog owner has strived to credit the original sources, but cannot warrant the accuracy of copyrights or completeness of the information sources.