Luminance Calculator

Luminance Formula:

\[ L_v = \frac{I_v}{A \times \cos(\theta)} \]

Luminous Intensity (I_v):

Candela

Area of Illumination (A):

m²

Illumination Angle (θ):

radians

Luminance (L_v):

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1. What is Luminance?

Luminance refers to the amount of light emitted, reflected, or transmitted by a surface or object per unit area. It measures the brightness or intensity of the light perceived by an observer.

2. How Does the Calculator Work?

The calculator uses the Luminance formula:

\[ L_v = \frac{I_v}{A \times \cos(\theta)} \]

Where:

\( L_v \) — Luminance (Lux)
\( I_v \) — Luminous Intensity (Candela)
\( A \) — Area of Illumination (m²)
\( \theta \) — Illumination Angle (radians)

Explanation: This formula calculates the luminance by dividing the luminous intensity by the product of the illuminated area and the cosine of the illumination angle.

3. Importance of Luminance Calculation

Details: Luminance calculation is crucial for lighting design, visual comfort assessment, and ensuring appropriate illumination levels in various environments.

4. Using the Calculator

Tips: Enter luminous intensity in candela, area in square meters, and illumination angle in radians. All values must be valid (positive values).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between luminance and illuminance?
A: Luminance measures the amount of light emitted from a surface, while illuminance measures the amount of light falling on a surface.

Q2: Why is the cosine function used in the formula?
A: The cosine function accounts for the angle of incidence, as light intensity decreases when it strikes a surface at an angle rather than perpendicularly.

Q3: What are typical luminance values?
A: Luminance values vary widely depending on the light source and surface. Typical values range from 0.001 cd/m² for dim surfaces to over 100,000 cd/m² for bright light sources.

Q4: How does illumination angle affect luminance?
A: As the illumination angle increases from perpendicular, the effective illuminated area increases, resulting in lower luminance values.

Q5: Can this calculator be used for all light sources?
A: This calculator works for point light sources and directional lighting. For complex lighting setups, additional factors may need to be considered.