Internal Transmittance Calculator

1. What is a Transmittance Calculator?

Definition: This calculator determines the transmittance and internal transmittance of a glass filter based on incident flux, transmitted flux, and reflection factor.

Purpose: Useful for analyzing optical filter performance.

2. How Does the Calculator Work?

The calculator uses the following steps:

Step 1: Transmittance

\( T(\lambda) = \frac{\Phi_{\lambda t}}{\Phi_\lambda} \)

Where:

\( \Phi_\lambda \): Incident flux
\( \Phi_{\lambda t} \): Transmitted flux

Step 2: Internal Transmittance

\( \tau_i(\lambda) = \frac{T(\lambda)}{P_d} \)

Where:

\( P_d \): Reflection factor

Steps:

Enter incident flux, transmitted flux, and reflection factor.
Calculate transmittance as a percentage.
Calculate internal transmittance as a percentage.

3. Importance of Transmittance

Transmittance is crucial for:

Optics: Designing filters for cameras and spectrometers.
Glass Manufacturing: Optimizing filter performance.
Lighting: Enhancing light transmission in optical systems.

4. Using the Calculator

Example 1: \( \Phi_\lambda = 100 \), \( \Phi_{\lambda t} = 90 \), \( P_d = 0.918 \):

Transmittance: \( T(\lambda) = \frac{90}{100} = 0.9 \), \( 90\% \)
Internal Transmittance: \( \tau_i(\lambda) = \frac{0.9}{0.918} \approx 0.98 \), \( 98\% \)
Result: \( T(\lambda) = 90\% \), \( \tau_i(\lambda) = 98\% \)

5. Frequently Asked Questions (FAQ)

Q: What if incident flux is zero?
A: The calculation cannot proceed; ensure a non-zero value.

Q: What is the reflection factor?
A: \( P_d \) accounts for losses due to reflection, typically around 0.918.

Q: Where to find flux values?
A: Refer to optical measurement data or manufacturer specs.