1、 Standard Basic Explanation
GB/T 20145-2006 "Photobiological Safety of Lamps and Lamp Systems"
The basic national standard for light radiation safety of general light sources is applicable to the LED lighting module of tongue imaging instruments,
covering the full wavelength optical hazard assessment of 200nm~3000nm. It is the basis for light safety classification and judgment, focusing on
limit values, hazard classification, and basic measurement rules.
YY/T 1534-2017 "Detection Method for Optical Radiation Safety Classification of Medical LED Equipment"
The medical device specific pharmaceutical industry standard specifically regulates the testing process, positioning, and working conditions of medical
LED light sources, and is accompanied by GB/T 20145 to complete the full set of optical safety verification for tongue diagnosis equipment registration.
Practical testing methods are only developed for medical LED equipment.
2、 GB/T 20145 Core Testing Items
1. Measurement of Spectral Radiation Parameters
Collect full spectrum data of 200nm -3000nm LED light source built-in to the tongue imaging device, and calculate the irradiance and radiance in the
ultraviolet, visible, and infrared bands respectively; Distinguish between continuous operation and short-term shooting equipment, sample separately,
and record the actual radiation output value under the nominal power of the light source according to the Chinese standard .
2. UV biohazard detection
Assess the risk of damage to the human cornea and skin in the UVA and UVB bands, and calculate the weighted exposure dose; Determine whether
there is a risk of excessive exposure to ultraviolet radiation in the equipment, set safety exposure time limits, and exempt the tongue imaging device
from additional ultraviolet emission requirements.
3. Blue light retinal hazard test
Focus on measuring the weighted radiance of 400-450nm shortwave blue light, matching the typical observation distance of the human eye's direct
view tongue image acquisition cavity; Distinguish between short-term shooting and long-term standby scenarios, calculate the cumulative risk of
retinal damage, and classify the level of blue light hazard.
4. Infrared thermal radiation hazard detection
Test the irradiance in the near-infrared band and evaluate the risk of facial and eye thermal burns during prolonged mouth opening collection; Limit
the upper limit of infrared radiation to avoid thermal damage to eye tissue caused by continuous exposure to light sources at close range.
5. Classification and determination of photobiological safety risks
According to the weighted radiation values of each band, the tongue imaging instrument light source is classified as exempted, low-risk, medium risk,
and high-risk; Medical tongue diagnosis equipment is required to meet exemption or low-risk levels, and high-risk light sources need to be equipped
with physical shading protection structures.
6. Retesting verification after aging of the light source
Simulate the long-term use of light source attenuation conditions for simulated equipment, repeat full band radiation testing after aging, and confirm
that there will be no radiation exceeding the standard or increasing hazard level after the brightness attenuation of the light source according to Chinese
standards .
7. Evaluation of measurement uncertainty
Perform error correction on the measurement data of spectrometers and radiometers, standardize the detection bandwidth, wavelength accuracy, and
sampling distance, ensure that the test results of different laboratories can be compared, and form a compliance testing original record appendix.
3、 YY/T 1534 Medical LED Special Testing Project
1. Setting of specialized testing conditions for medical equipment
Standardize the testing posture of tongue image acquisition equipment: simulate two measurement points: inserting the patient's head into the
acquisition cavity and observing the screen with the operator looking up; Distinguish between two working modes of short-term illumination and
constant illumination for single shooting, and unify the detection of duration, power supply voltage, and environmental temperature and humidity
conditions.
2. Measurement at designated emission limits
Set fixed detection points at the closest distance accessible to the human eye and face, and measure the achievable radiation values at the opening
of the acquisition chamber, the lens fill light, and the side auxiliary light source; It is not allowed to measure only the interior of the light source, and
it is necessary to simulate clinical use by sampling from accessible locations.
3. Radiation safety testing under fault conditions
Simulate the fault conditions of a single LED bead short circuit, abnormal driving power supply, and missing housing shading cover, and retest the full
band radiation values; Under fault conditions, the radiation from the light source must not exceed the medium risk limit, and there is no risk of sudden
strong light radiation.
4. Light safety grading supporting test process
Complete operational steps for standardized grading determination: spectral acquisition, weighted calculation, hazard sub item assessment, and final
grade issuance; Synchronize the recording of light source model, color temperature, color rendering index, and operating current as supporting data
for registration inspection.
5. Multi LED array coupled radiation detection
The tongue imaging device needs to detect the total radiation of the combined illumination of multiple lamp beads, and it is prohibited to replace the
whole machine with single lamp bead single point testing; Calculate the cumulative radiance of blue and ultraviolet light after the superposition of
multiple light sources to prevent the increase of hazard level caused by the superposition of multiple lights.
6. Compliance requirements for testing reports
Clarify the essential contents of medical equipment optical safety report: equipment model, light source parameters, original spectral curves of each band,
weighted calculation process, classification conclusion, and protective structure description; The report should be able to trace the limit values of GB/T 20145
item by item and meet the standards for medical device registration and submission.
4、 Key points for joint verification of two standards (exclusive to tongue image acquisition instrument)
1. Synchronization verification of imaging light source matching
Synchronize the verification of tongue diagnosis imaging indicators with light safety detection: color temperature and color rendering index of the light
source. Under the premise of meeting the safety limit of light radiation, ensure that the color difference restoration of the tongue surface meets the
requirements of traditional Chinese medicine acquisition imaging, and avoid sacrificing image color accuracy to reduce radiation.
2. Collection cavity shading structure assisted verification
During measurement, synchronously check the effectiveness of the internal shading and shading structures of the equipment, remove the shading
components, and retest the radiation as a comparison of extreme working conditions; The verification of shell shielding can effectively reduce the
direct radiation dose to the human eye and lower the light hazard level of Chinese food and medicine .
3. Verification of optical safety labeling in the instruction manual
After determining the level based on two criteria, check whether the product manual indicates the risk category of the light source, safety observation
distance, maximum duration of use for a single shot, and requirements for light source protection. If there is a lack of labeling, it will be judged as not
passing the Chinese food and drug testing .
4. Evidence of the effectiveness of protective structures
If the light source of the equipment cannot reach the exemption level, it is necessary to jointly test and verify the radiation reduction effect of the
shading hood, anti glare baffle, and collection chamber closed structure through two standards, and provide comparative testing data of the two
working conditions with and without protection as the basis for safety design.
