GB/T 9473-2022Performance requirements for table lamps for paper task (English PDF)

3.6 Modulation depth

Modulation The ratio of the difference between the maximum and minimum values of the light output in one cycle to the sum of the maximum and minimum values of the light output.

NOTE: The term "modulation depth" comes from IEEE Std 1789.The corresponding English term in GB/T 2900.65 is amplitude of fluctuation. The definitions of the two terms are the same. Modulation depth is expressed as a percentage.

3.7 Temporal light artifact; TLA

The visual perception of human observers in a specific environment caused by light stimuli whose brightness or spectral distribution fluctuates over time.

NOTE: Visual change perception is the result of comparing the visual perception of an environment illuminated by modulated light with the visual perception of the same person when the same environment is illuminated by non-modulated light. [Source: CIE TN 006.2016, 2.4.1]

3.8 Flicker

For static observers in a static environment, light stimuli whose brightness or spectral distribution fluctuates over time induce visually unstable perceptions.

NOTE 1: The temporal changes of light stimulation include periodic and non-periodic ones, which may be caused by the light source itself, the power supply or other influencing factors.

NOTE 2: Flicker is a type of transient light artifact. [Source: CIE TN 006.2016, 2.4.2]

3.9 Stroboscopic effect

For static observers in non-static environments, changes in the perception of motion caused by light stimuli whose brightness or spectral distribution fluctuates over time.

NOTE: The stroboscopic effect is a type of temporal light artifact.

Example 1.When brightness changes in a periodic square wave, moving objects are perceived as discrete rather than continuous motion.

d) General color rendering index Ra and (or) special color rendering index R9.

e) Rated input power and power factor.

f) The normal attitude of the table lamp, including.

- The relative position between the light-emitting surface of the table lamp and the effective working area for lighting reading and writing tasks;

- The height of the light-emitting surface;

- The tilt angle of the light-emitting surface;

- The placement and direction of the table lamp and other information.

g) Rated operating time of the table lamp with charging device.

NOTE 1: The instruction manual can be in paper form or in electronic form, such as a QR code or other form.

- LED table lamp modulation depth level specified in 5.5.2;

- The threshold level at which stroboscopic effects and flicker may be observed is […]

5.7 Power factor

The measured value of power factor shall not be lower than the nominal value by 0.05 or more.

a) For table lamps with a power greater than 5 W and less than 25 W, the nominal power factor shall not be less than 0.5;

b) For table lamps with a power greater than 25 W, the nominal power factor shall not be less than 0.9.

NOTE: When the measured power is not less than 90% and not more than 110% of the rated input power, the limit value is determined according to the rated input power. When the measured power exceeds the above range, the limit value is determined according to the measured power.

5.8 Electromagnetic radiation from table lamps to the human body

It shall comply with the requirements of GB/T 31275.

5.9 Blue light hazards to the retina

According to GB/Z 39942-2021, the retinal blue light hazard category shall be RG0.

5.10 Noise

The noise level of a table lamp containing a lamp control device shall not be greater than 25 dB(A) when operating normally.

6.1 General test conditions

6.1.1 The test shall be carried out in a room without convection airflow, with relative humidity not exceeding 65% and an ambient temperature of 25°C±1°C.

6.1.2 Unless otherwise specified, the test shall be carried out at rated voltage and rated frequency. If the rated voltage is a range, it shall be measured at 220 V and 50 Hz.

6.1.3 The test power supply voltage and frequency error shall be kept within ±0.2% of the nominal value.

6.1.4 The total harmonic content of the test power supply voltage shall not be greater than 3%.

6.1.5 The accuracy of the electrical instruments used shall not be lower than Class 0.2.

The accuracy of the illumination measuring instrument shall not be lower than Class 1 requirement in JJG 245.

6.1.6 Before the lamp brightness test, it shall be aged according to the relevant light source performance standards.

6.2 Appearance of lamps

The external dimensions of the lamps shall be inspected with a general measuring tool with an accuracy of not less than 0.1 mm. The color and structure shall be inspected visually.

6.3 Marks

The integrity of the marking content is checked visually. The firmness of the marking is checked by the method specified in 3.4 of GB 7000.1-2015.

6.4 Luminosity

6.4.1 Light blocking and anti-glare

The working position of the table lamp during the shading and anti-glare tests shall be consistent with that during the illuminance and illuminance uniformity tests.

Place the lamp on a level table in its normal attitude. Take measurements after the light source has stabilized. First, place the lens center of the luminance meter at a height of 400 mm from the table, 600 mm from the geometric center of the light source cavity surface, and perpendicular to the edge of the table. The position passes through the geometric center of the light source cavity surface, as shown in Figures 1 and 2.Then adjust the horizontal and vertical angles of the luminance meter during the test. Measure the surface brightness of all light sources, translucent components, and reflective components observed.

For table lamps with the light-emitting surface in the normal attitude higher than 750 mm relative to the tabletop, the part above this height is exempted. […]