1. Types of Desk Lamp Light Sources

1. Thermal light sources: incandescent lamps and halogen lamps

Advantages: The spectrum is relatively continuous and closest to natural light, making it an excellent light source.

Disadvantages: They emit a large amount of infrared radiation and generate considerable heat, which can easily cause dry eyes and a feeling of pressure in the head. In addition, their relatively low color temperature makes the light appear yellowish, which can easily cause drowsiness.

2. Fluorescent lamps: compact fluorescent lamps and fluorescent tubes

Advantages: Minimal flicker, high brightness, energy efficiency, and a longer service life than incandescent lamps.

Disadvantages: The light source of energy-saving lamps is not sufficiently stable and has a relatively high color temperature, making it likely to irritate the eyes when used for close-range lighting.

3. LED lamps

Advantages: LED lamps are small in size, have a long service life, low energy consumption, and are environmentally friendly. They also have no flicker and no radiation.

Disadvantages: They are relatively expensive, and counterfeit products are easy to purchase.

2. Optical Performance Requirements

To determine whether a desk lamp is qualified, it must first meet three optical performance requirements when the lamp is in its normal working position for writing.

1. Glare shielding: When a person is sitting in a normal posture and looking horizontally, the inner wall of the lampshade and the light source should not be visible.

2. Desk illumination requirements: The illumination in the working area illuminated by the desk lamp should be 250 lx–500 lx, and the minimum illuminance should be ≥120 lx.

3. Illuminance uniformity requirements: The illuminance in the working area illuminated by the desk lamp should be relatively uniform, without excessively bright or dark spots.

Only by ensuring that the above three basic optical performance requirements are met can eye fatigue be alleviated.