Calculator Inputs
Formula Used
Eeff = Eref × (dref / dwork)² × T × cos(θ) × e-αL
tideal = Htarget / Eeff
trec = tideal × (1 + Safety Factor)
Hdelivered = Eeff × t
This model combines inverse-square distance loss, filter transmission, cosine angular loss, and Beer-Lambert absorption. Because mW/cm² equals mJ/cm² per second, dividing target dose by corrected irradiance directly gives seconds.
How to Use This Calculator
- Enter the source irradiance measured at a known reference distance.
- Provide the actual working distance used in your process.
- Enter filter transmittance, angular incidence, and any medium absorption data.
- Input the target dose required by your coating, sensor, adhesive, or curing step.
- Add a safety factor if your process needs extra delivered dose.
- Use dose tolerance to estimate the acceptable time window.
- Press the calculate button to view the result above the form.
- Review the graph, then export your result as CSV or PDF.
Example Data Table
| Case | Irradiance (mW/cm²) |
Ref Dist (cm) |
Work Dist (cm) |
Filter (%) |
Angle (°) |
Absorption (1/cm) |
Path (cm) |
Target Dose (mJ/cm²) |
Recommended Time (s) |
|---|---|---|---|---|---|---|---|---|---|
| Optical Curing A | 22 | 10 | 18 | 85 | 20 | 0.04 | 2.5 | 140 | 31.95 |
| Inspection Exposure B | 35 | 12 | 20 | 92 | 10 | 0.02 | 1.2 | 180 | 17.44 |
| Coating Process C | 18 | 8 | 15 | 75 | 30 | 0.06 | 3.0 | 90 | 37.26 |
Frequently Asked Questions
1) What does this exposure time calculator estimate?
It estimates the process time needed to reach a target energy dose after distance loss, filter transmission, angle loss, and medium absorption are applied.
2) Why does distance strongly affect exposure time?
The tool uses an inverse-square relation. As working distance increases, irradiance falls quickly, so the required exposure time rises substantially.
3) Why is angle included?
Oblique exposure reduces effective power on the surface. The cosine factor models that geometric reduction and is useful for tilted fixtures or angled beams.
4) What does the absorption coefficient represent?
It represents energy loss through a medium. Higher absorption or longer path length reduces transmitted irradiance and increases the time required to achieve the target dose.
5) When should I use a safety factor?
Use it when your process needs extra margin for lamp aging, alignment error, material variability, or dose measurement uncertainty.
6) What is the acceptable time window?
It is the exposure range that keeps delivered dose within your stated tolerance band around the target dose.
7) Can this tool help with UV curing or optical inspection?
Yes. It is suitable for UV curing, surface exposure studies, lamp process setup, optical inspection planning, and other engineering dose applications.
8) Which units should I use?
Use mW/cm² for irradiance, mJ/cm² for target dose, centimeters for distance and path length, percent for transmission, and degrees for angle.