2025-02-03

ISO/DIS 9680:2025(en)

ISO TC 106/SC 6/WG 1

Secretariat: DIN

Dentistry — Operating lights

Médecine bucco-dentaire — Luminaires opératoires

© ISO 2025

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Contents

Foreword v

Introduction vii

1 Scope 1

2 Normative references 1

3 Terms and definitions 1

4 Requirements 2

4.1 Optical requirements 2

4.1.1 Adjustable level of illuminance 2

4.1.2 Illumination pattern 2

4.1.3 Illuminance in patient's eyes 4

4.1.4 Chromatic uniformity 4

4.1.5 Chromaticity and correlated colour temperature 5

4.1.6 Shadow 5

4.1.7 Colour fidelity 6

4.1.8 Actinic UV hazard exposure for the skin and eye 6

4.1.9 Near-UV hazard exposure for the eye 6

4.1.10 Retinal blue light hazard exposure 6

4.1.11 Single fault condition for photobiological safety 6

4.1.12 Heat due to optical radiation 7

4.1.13 Compatibility with light-activated restorative materials 7

4.2 Mechanical requirements 7

4.2.1 Operating controls 7

4.2.2 Stability after positioning 7

4.2.3 Expelled parts 7

4.3 Reprocessing 7

4.4 Electrical requirements 8

4.5 Usability 8

5 Sampling 8

6 Testing 8

6.1 General 8

6.2 Visual inspection 8

6.3 Optical tests 8

6.3.1 Test set-up 8

6.3.2 Level of illuminance and illuminance pattern 9

6.3.3 Illuminance uniformity 9

6.3.4 Illuminance in the patient’s eyes 9

6.3.5 Chromatic uniformity 9

6.3.6 Chromaticity and correlated colour temperature 10

6.3.7 Shadow 10

6.3.8 Colour fidelity 11

6.3.9 Actinic UV hazard exposure for the skin and eye 11

6.3.10 Near-UV hazard exposure for the eye 12

6.3.11 Retinal blue light hazard exposure 12

6.3.12 Heat due to optical radiation 14

6.3.13 Compatibility with light-activated restorative materials 14

7 Manufacturer's instructions 14

7.1 Documents 14

7.2 Instructions for use 14

7.3 Technical description 15

7.4 Check 15

8 Packaging 15

8.1 General 15

8.2 Identification 15

9 Marking 16

9.1 Marking on the outside of operating lights 16

9.2 Graphical symbols 16

Annex A (informative) 17

A.1 Background 17

A.2 Test setup and measurement equipment 17

A.2.1 Test setup 17

A.2.2 Measurement equipment 17

A.2.2.1 Radiometric instrument 17

A.2.2.2 Imaging Luminance Measurement Device (ILMD) 18

A.2.3 Field Stop 18

A.3 Measurement method 19

A.3.1 Determination of the location of the maximum blue light weighted irradiance 19

A.3.2 Measurement of blue light weighted irradiance 20

A.4 Calculation of retinal blue light weighted radiance and permissible exposure duration 20

Annex B (normative) Normalized absorbance of camphorquinone 22

Bibliography 23

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 106, Dentistry, Subcommittee SC 6, Dental equipment, in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 55, Dentistry, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This fifth edition cancels and replaces the fourth edition (ISO 9680:2021), which has been technically revised.

The main changes are as follows:

— Clause 4 “Classification” has been deleted and the following Clauses have been re-numbered;

— Clause 5 “Requirements and Recommendations” was adapted to Clause 4 “Requirements” and technically updated;

— Clause 7.4 “Mechanical tests” and all sub-clauses have been deleted;

— Clause 9 “Marking” was technically updated;

— Annex A “Transformation formulae” has been deleted;

— A new informative Annex A on “Additional information for retinal blue light hazard exposure test method” has been added;

— the normative references were updated;

— editorial updates.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

This document provides the dentist and his staff with means to enable them to work with optimum visual ease and comfort, i.e. a visual acuity of 90 % to 100 % according to zone, without adversely affecting their perception of colour or causing excessive fatigue or photobiological injury.

In this document, the safety of an operating light is assessed in combination with its power supply. Such power supplies may be incorporated in dental units or dental patient chairs.

Any item of equipment recommended by the manufacturer for use in conjunction with an operating light should not render the equipment unsafe nor affect its qualities adversely.

IEC 60598-1 has been taken into account during the preparation of this document.

IEC 60601-1 specifies requirements pertaining to the basic safety and essential performance of medical electrical equipment and medical electrical systems. IEC 80601-2-60 specifies requirements pertaining to the basic safety and essential performance of dental units, dental patient chairs, dental handpieces and dental operating lights. Requirements of IEC 60601-1 and IEC 80601-2-60 applicable to operating lights are not duplicated in this document.

Dentistry — Operating lights

This document specifies requirements and test methods for operating lights used in the dental treatment and intended for illuminating the oral cavity of patients. It also contains specifications on the instructions for use, marking and packaging.

This document applies to operating lights, irrespective of the technology of the light source.

This document excludes auxiliary light sources and those intended for patient contact, for example, from dental handpieces and dental headlamps, fiberoptic intraoral operating light and also operating lights which are specifically designed for use in oral surgery.

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 9687, Dentistry — Graphical symbols for dental equipment

ISO 14971, Medical devices — Application of risk management to medical devices

ISO 15223‑1, Medical devices — Symbols to be used with information to be supplied by the manufacturer — Part 1: General requirements

ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories

ISO 17664‑1, Processing of health care products — Information to be provided by the medical device manufacturer for the processing of medical devices — Part 1: Critical and semi-critical medical devices

ISO 17664‑2, Processing of health care products — Information to be provided by the medical device manufacturer for the processing of medical devices — Part 2: Non-critical medical devices

ISO/CIE 19476, Characterization of the performance of illuminance meters and luminance meters

ISO 21530, Dentistry — Materials used for dental equipment surfaces — Determination of resistance to chemical disinfectants

IEC 62366‑1, Medical devices — Part 1: Application of usability engineering to medical devices

IEC 62471:2006, Photobiological safety of lamps and lamp systems

CIE 224, Colour Fidelity Index for accurate scientific use

For the purposes of this document, the terms and definitions given in ISO 1942, ISO 4073, IEC 60598-1, IEC 60601-1, CIE S 017 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

3.1

operating light

device designed for use by an operator for illuminating the oral cavity, which either distributes, filters or transforms the light, or does any combination of these, transmitted from one or more light sources and which includes all parts necessary for supporting, fixing and protecting the light sources, and circuit auxiliaries together with the means of connecting them to the supply

3.2

light-activated restorative material

dental material intended for oral use that incorporates a monomer system, the polymerization of which is activated by light

The level of illuminance shall be adjustable. The adjustment of illuminance may be either continuous or in discrete levels.

The manufacturer shall specify nominal values for the minimum illuminance and maximum illuminance at a distance of 700 mm from the operating light. The maximum nominal illuminance specified by the manufacturer shall be at least 15 000 lx. The measured minimum illuminance and maximum illuminance shall be within 20% of the respective nominal values specified by the manufacturer.

Test in accordance with 6.2 and 6.3.2.

The requirements of 4.1.1 do not apply to any operating mode(s) intended only for use while handling light-activated restorative materials.

Illumination areas and illuminance levels

The illumination pattern shall be measured to determine the maximum illuminance, E_v,max, and the following iso-illuminance lines in accordance with 6.3.2: 0,90 × E_v,max, 0,75 × E_v,max, 0,50 × E_v,max, 0,10 × E_v,max and 1 200 lx.

An area A is defined as the area bounded by the iso-illuminance line corresponding to 75 % of the maximum illuminance. The border of area A shall be on or outside of an ellipse with a horizontal axis of 50 mm and a vertical axis of 25 mm, in which the horizontal axis and vertical axis of the ellipse are aligned with the major axis and minor axis of the illumination pattern, respectively (see Figure 1). The illuminance shall not be less than 75 % of E_v,max throughout the ellipse. Test in accordance with 6.3.2.

An area B is defined as the area bounded by the iso-illuminance line corresponding to 50 % of the maximum illuminance. The border of area B shall be on or outside of an ellipse with a horizontal axis of 80 mm and a vertical axis of 40 mm and with the same axes as the smaller ellipse associated with area A (see Figure 2). Test in accordance with 6.3.2.

Dimensions in millimetres

Key

Figure 1 — Example of illumination pattern which satisfies the requirement for area A

Dimensions in millimetres

Key

Figure 2 — Example of illumination pattern which satisfies the requirement for area B

Illuminance uniformity

The illuminance shall decrease in intensity progressively and smoothly toward the pattern edge.

Test in accordance with 6.3.3.

An area C is defined as the area bounded by the iso-illuminance line corresponding to 90 % of the maximum illuminance. The level of illuminance at all points on or above a horizontal line 60 mm above the uppermost point of area C shall not be greater than 1 200 lx (see Figure 3).

The operating light should be capable of rotating about the x-, y- and z-axes of the Cartesian coordinate system to allow the operator maximum flexibility in positioning the operating light while preventing excessive illuminance in the patient’s eyes.

EXAMPLE 1 Rotation of the operating light about the x-, y- and z-axes of the Cartesian coordinate system can be achieved by three rotational pivot axes incorporated into the positioning arm of an operating light, even if the three rotational pivot axes are not perpendicular to one another.

EXAMPLE 2 Rotation of the operating light about the x-, y- and z-axes of the Cartesian coordinate system can be achieved by a ball-and-socket joint incorporated into the positioning arm of an operating light.

Test in accordance with 6.3.4.

Dimensions in millimetres

Key

Figure 3 — Example of illumination pattern which satisfies the requirement for limiting illuminance in the patient’s eyes

No perceptible chromatic variation (colour separation) of the light incident upon the measuring screen shall be visible in area A and area B.

Test in accordance with 6.3.5.

Over the full range of illuminance levels, the correlated colour temperature shall be in the range of 3 600 K to 6 400 K within areas A and B of the illuminance pattern. D_uv (the perpendicular distance in the 1960 CIE Uniform Chromaticity Scale (u,v) between the Planckian locus and the chromaticity coordinates of the operating light) shall be within the range of -0,01 to +0,01.

For reference the chromaticity limits in CIE (u,v) coordinates are depicted in Figure 4.

Preferably, when the operating light is adjusted to the maximum illuminance level, the correlated colour temperature should be between 4 500 K and 6 400 K.

Test in accordance with 6.3.6.

The requirements of 4.1.5 do not apply to any operating modes intended only for use while handling light-activated restorative materials.

Key

Figure 4 — Chromaticity limits in CIE (u,v) coordinates

The hard shadow of a disc with 20 mm diameter at a distance of 50 mm shall have no dimension greater than 12 mm.

Test in accordance with 6.3.7.

For general illumination of the oral cavity, the operating light shall have a general colour fidelity index, R_f, of at least 85.

NOTE The importance of accurately assessing colour in dental diagnosis and treatment while using an operating light supports specifying R_f as the measure for colour fidelity in this document even though CIE 224 indicates that R_f is not intended as a universal replacement for the general colour rendering index, R_a, at this time. The decision to specify R_f in this document was made in consultation with CIE.

Test in accordance with 6.3.8.

The requirements of 4.1.7 do not apply to any operating modes intended only for use while handling light-activated restorative materials.

The risk group classification of the operating light for actinic ultraviolet hazard (E_s) shall be Risk Group 1 or lower, as specified in IEC 62471:2006, 6.1, when tested under the conditions specified in 6.3.9. Unless the operating light is classified as an exempt group for actinic ultraviolet hazard, the permissible exposure duration, t_max, per IEC 62471:2006, 4.3.1 shall be calculated in accordance with 6.3.9.

Compliance with this requirement shall be verified either by documentation (e.g. test report by the light source manufacturer) which verifies that all of the light sources used in the operating light do not emit in the applicable wavelength range (200 nm to 400 nm), or by testing in accordance with 6.3.9.

The risk group classification of the operating light for near-UV hazard (E_UVA) shall be Risk Group 1 or lower, as specified in IEC 62471:2006, 6.1, when tested under the conditions specified in 6.3.10.

Unless the operating light is classified as exempt group for near-UV hazard, the permissible exposure duration, t_max, per IEC 62471:2006, 4.3.2 shall be calculated in accordance with 6.3.10.

Compliance with this requirement shall be verified either by documentation (e.g. test report by the light source manufacturer) which verifies that all of the light sources used in the operating light do not emit in the applicable wavelength range (315 nm to 400 nm), or by testing in accordance with 6.3.10.

The risk group classification for retinal blue light hazard (L_B) per IEC 62471:2006, 6.1 shall be Risk Group 1 or lower when tested under the conditions specified in 6.3.11.

Unless the operating light is classified as exempt group for retinal blue light hazard, the permissible exposure duration, t_max, per IEC 62471:2006, 4.3.3 shall be calculated in accordance with 6.3.11.

Test in accordance with 6.3.11.

Analysis under single fault condition shall be applied to the requirements for actinic UV exposure for skin and eye (see 4.1.8), near-UV exposure for the eye (see 4.1.9) and retinal blue light hazard exposure (see 4.1.10). The operating light shall be considered single fault safe (IEC 60601-1:2005+AMD1:2012+AMD2:2020, 4.7) if the risk group classification of the operating light does not exceed Risk Group 2 given in IEC 62471:2006, 6.1 under single fault condition.

NOTE 1 A single fault condition, such as a short circuit or an open circuit of any component other than a component with high-integrity characteristics or a software failure, can lead to a higher LED driving current, increased light emission and a higher photobiological risk group classification.

NOTE 2 Analysis of the photobiological safety in single fault condition can be conducted based on the change in illuminance under single fault condition relative to illuminance under normal conditions if the emission spectrum in single fault condition is equivalent to the emission spectrum in normal conditions.

The irradiance over the wavelength range of 300 nm to 2 500 nm shall be ≤350 W/m² (35 mW/cm²) at the maximum illuminance level at a distance of 700 mm from the operating light.

Test in accordance with 6.3.12.

If the operating light is equipped with a setting intended for use while handling light-activated restorative materials, the maximum illuminance in this setting shall be at least 6 500 lx and the camphorquinone-weighted irradiance shall be less than 3,0 W/m² (0,3 mW/cm²) when tested under the conditions specified in 6.3.13. The camphorquinone-weighted irradiance is the integral of the product of the operating light irradiance spectrum and the normalized absorption spectrum of camphorquinone over the wavelength range of 400 nm to 515 nm (see 6.3.13).

NOTE The photo-initiator systems of commercial dental restorative materials are currently based on one or more of the following: camphorquinone, 1-phenyl-1,2 propanedione (PPD), or acylphosphine oxides. Each of these photo-initiators has a different absorbance spectrum. Since the absorbance spectrum of camphorquinone extends to longer wavelengths than the other photo-initiators, the overlap with the emission spectrum of operating lights is greatest with camphorquinone. Therefore, the camphorquinone absorbance spectrum is expected to represent the worst-case challenge for evaluating possible effects of dental operating lights on light-activated restorative materials.

Test in accordance with 6.3.13.

Operating controls shall be designed and located to minimize accidental activation. Graphical symbols for operating controls and performance shall be in accordance with ISO 9687.

Operating lights should be free from apparent drift when positioned.

The operating light shall be designed to provide protection against the effects of the shattering of its light source if it is possible for the light source to shatter. This requirement is not relevant for LED light sources.

The operating light shall so be designed that particles from a shattering light source cannot impair safety. This shall be verified by appropriate risk analysis in accordance with ISO 14971.

All exterior touchable parts of the operating light shall be suitable for reprocessing using the agents and methods recommended by the manufacturer without deterioration of surfaces or labelling.

The manufacturer shall provide information on the reprocessing for the operating light in accordance with ISO 17664-1 and ISO 17664-2, as applicable. Preferably, the handles should be sterilizable or capable of accommodating reusable, sterilizable covers.

Testing of resistance against cleaning and disinfection shall be carried out in accordance with ISO 21530.

Operating lights shall be suitable for continuous operation. Conformity shall be verified by checking the manufacturer’s documentation.

NOTE The designation of continuous operation is relevant to determining the applicability of certain electrical requirements of IEC 60601-1 and IEC 80601-2-60.

Usability evaluation shall be carried out following the process described in IEC 62366-1.

Testing shall be carried out in accordance with IEC 62366-1.

All type tests shall be made on one representative sample of the operating light.

All tests described in this document are type tests.

Testing shall be performed at an ambient temperature of (23 ± 2) °C. The relative humidity shall be between 30 % and 70 %.

All measurements of optical radiation shall be traceable to the international system of units (SI) implemented through the requirements of ISO/IEC 17025.

Visual inspection shall be performed at normal visual acuity without magnification.

Aim the light beam at a measuring screen, perpendicular to the optical axis, at a distance of 700 mm measured from the external most forward part of the operating light from which light is emitted.

Adjust the controls for illumination during the tests at the setting of the maximum illuminance level and operate until the irradiance and colour have stabilized, as determined by monitoring the running average of the measurements, before collecting measurements for the tests specified in 6.3.2 through 6.3.13 unless otherwise specified.

Establish a rectangular coordinate system in the measurement plane with the origin of coordinates (i.e. the coordinate axis intersection point) centrally placed in the zone of maximum illumination level and with the x-axis parallel to the major axis of the illumination pattern. If there is a marked cut-off in the y-direction, take this as the positive direction. If there is not a marked cut-off in the y-direction, arbitrarily select a direction to be the positive direction.

For tests specifying visual assessment of the illuminance pattern, place a uniform, neutral, diffusely reflecting, flat white screen in the measurement plane. For tests requiring instrumented measurements, place the specified detector in the measurement plane unless otherwise specified.

Perform optical tests in a room where light from other sources and reflected light from room surfaces are negligible.

If the operating light is designed to be used at a target distance other than 700 mm, testing shall also be performed at the intended operating distance.

Use the test set-up as described in 6.3.1.

Measure the illuminance levels with a photometer calibrated in accordance with ISO/CIE 19476 and having an acceptance aperture with a diameter of 10 mm.

Moving the photometer within the measurement plane, make measurements at rectilinear coordinates not more than 5 mm apart, such that all points within the illuminance pattern having an illuminance greater than 600 lx are measured.

A photometer that can indirectly record the illuminance distribution with one measurement, i.e. an imaging luminance measurement device (ILMD), may be used for this purpose. In such a case, the illuminance pattern is normally projected onto a flat, uniform, diffusely reflecting screen positioned in the measurement plane and the luminance distribution of the reflected light measured using the ILMD. The uniformity and directional response of the reflectance characteristics of the screen shall be evaluated and either corrected for or taken into account in the measurement uncertainties.

Record the measurements and their location. Determine the maximum illuminance, E_v,max. Use linear interpolation of measurements to calculate and plot the following iso-illuminance lines specified in 4.1.2.1: 0,90 × E_v,max, 0,75 × E_v,max, 0,50 × E_v,max, 0,10 × E_v,max and 1 200 lx. Check whether the requirements given in 4.1.1 and 4.1.2.1 are fulfilled.

Use the test set-up as described in 6.3.1.

The requirement is fulfilled if no bright rings or bright spots outside of the central maximum are visually apparent.

Using the illuminance pattern data from 6.3.2, determine the coordinates of the uppermost point of area C (i.e. the point along the iso-illuminance line corresponding to 90 % of the maximum illuminance which is farthest from the horizontal axis in the direction of the patient’s eyes, i.e. positive y-direction). Plot a horizontal line 60 mm above the uppermost point of area C. Check whether the illuminance at any point along or above the horizontal line exceeds 1 200 lx (see Figure 3).

To confirm whether there are any areas of brightness above the horizontal line, place a flat white screen in the measurement plane. Observe whether there are areas of brightness above the horizontal line 60 mm above the uppermost point of area C when viewed by a person with normal visual acuity at a distance of 50 cm to 75 cm. If any areas appear brighter than along the horizontal line 60 mm above the uppermost point of area C, measure the illuminance in those areas using a calibrated photometer, as described above.

Record the measurements and their location. Check whether the requirement specified in 4.1.3 is fulfilled.

Adjust the room lighting to an illuminance level in the range of 1 % to 3 % of the maximum illuminance of the operating light, measured at the centre of the measurement plane with a calibrated illuminance meter oriented toward the room light source. Place a flat white screen in the measurement plane and illuminate it with the operating light. Use three people with normal colour vision to observe whether there are any colour non-uniformities within area A and area B when viewed at a distance of 50 cm to 75 cm. The normal colour vision of the observers shall be verified within the past five years by at least one of the following:

— evaluation for colour vision by a medical practitioner or other appropriately trained person;

— the Ishihara colour vision test, either digitally or physically using colour assessment cards; or

— the Richmond HRR Pseudoisochromatic Plates 4th edition colour vision test, either digitally or physically using colour assessment cards (Good-Lite, USA).

Corrective untinted lenses may be worn.

Use the test set-up as described in 6.3.1 with the operating light set at maximum light output.

Determine the chromaticity coordinates at the point of maximum illuminance in the measurement plane, using a tristimulus colourimeter or spectroradiometer and software with the capability to calculate correlated colour temperature and D_uv. Check whether the measured values for correlated colour temperature and D_uv comply with the requirements specified in 4.1.5.

Repeat the test at each illuminance level of the operating light. If the operating light has continuous illuminance adjustment or more than three illuminance levels, it is acceptable to test at the maximum illuminance level, minimum illuminance level and one illuminance level at approximately the midpoint of the illuminance range.

Place the operating light to be tested at a distance of 700 mm from a measuring screen marked with a rectangular coordinate system (see Figure 5), with the light beam normal to the measuring screen and the illuminance pattern axes coincident with the measuring screen coordinates.

Place a support column outside the measurement area, supporting a 20 mm diameter disc that is 1-mm thick and opaque. Position the disc parallel to the measuring screen with the centre of the disc on the axis normal to the measuring screen coordinates at a distance of 50 mm from the screen. Measure the hard shadow cast on the target on the two main axes.

Dimensions in millimetres

Key

Figure 5 — Device for determination of shadow reduction

Measure R_f in accordance with CIE 224 at the point of maximum illuminance in the measurement plane. Check whether the requirement specified in 4.1.7 is fulfilled.

Measure the effective ultraviolet irradiance, E_s, in accordance with IEC 62471:2006 using a measurement distance of 700 mm and a detector with an input diameter in the range of 7 mm to 30 mm.

Perform measurements with the operating light set at maximum light output. If the operating light has multiple operating modes with different normalized spectral power distributions (e.g. white light mode and mode intended for use while handling light-activated restorative materials, or white light modes with different correlated colour temperatures), perform measurements in each operating mode with the operating light set at maximum light output.

Assess the risk group classification for actinic ultraviolet hazard according to IEC 62471:2006, 6.1 for each operating mode. The highest assessed risk group classification of all operating modes is designated as the risk group classification of the operating light for actinic ultraviolet hazard.

Check whether the risk group classification of the operating light meets the requirement specified in 4.1.8.

If the risk group classification is greater than exempt group, calculate t_max using the following formula:

t_max = 30/E_s

where

Measure the UV-A irradiance, E_UVA, in accordance with IEC 62471:2006 using a measurement distance of 700 mm and a detector with an input diameter in the range of 7 mm to 30 mm.

Perform measurements with the operating light set at maximum light output. If the operating light has multiple operating modes with different normalized spectral power distributions (e.g. white light mode and mode intended for use while handling light-activated restorative materials, or white light modes with different correlated colour temperatures), perform measurements in each operating mode with the operating light set at maximum light output.

Assess the risk group classification for near-UV hazard according to IEC 62471:2006, 6.1 for each operating mode. The highest assessed risk group classification of all operating modes is designated as the risk group classification of the operating light for near-UV hazard.

Check whether the risk group classification of the operating light meets the requirement specified in 4.1.9.

If the risk group classification is greater than exempt group, calculate t_max using the following formula:

t_max = 10 000/E_UVA

where

General

Test according to 6.3.11.2, which utilizes measurements of the individual light sources (e.g. LEDs, lamps or bulbs) of the operating light, or 6.3.11.3, which utilizes measurements of the operating light.

Method based on individual light source test results

This test method can be used only if all of the following criteria are met:

— test results made at a measurement distance of 200 mm in compliance with IEC 62471:2006 for all light sources used in the operating light are available (e.g. reported by the light source manufacturer);

— none of the light sources are classified as Risk Group 2 or Risk Group 3 given in IEC 62471:2006, 6.1 for retinal blue light hazard (L_B > 10 000 W/m²/sr);

— the distance between the centres of any two simultaneously emitting light sources is not less than 7,7 mm.

If any of the above criteria are not met, use the method specified in 6.3.11.3.

Based on test results made at a measurement distance of 200 mm in compliance with IEC 62471:2006, if all of the light sources are classified as exempt group or Risk Group 1 for retinal blue light hazard (L_B ≤ 10 000 W/m²/sr), the risk group classification of the operating light for retinal blue light hazard (L_B) is not greater than Risk Group 1, fulfilling the requirement specified in 4.1.10.

NOTE 1 Test results made at a measurement distance of 200 mm are specified in this method since that is the standard distance for evaluating lamps (i.e. light sources) per IEC 62471:2006. At the standard measurement, distance for operating lights (700 mm) L_B will be less than or equal to the value at 200 mm. Therefore, the actual risk group classification can be lower than determined by this method.

NOTE 2 A distance of 7,7 mm between light sources results in an angular subtense of 0,011 rad at 700 mm from the light source, which is the specified angular subtense for assessing Risk Group 1 classification for retinal blue light hazard. If any two simultaneously emitting light sources are spaced more closely than 7,7 mm, their combined emissions can result in the operating light having a higher risk group classification.

If the risk group classification of any of the individual light sources of the operating light is Risk Group 1, calculate t_max using the following formula with the greatest value for L_B if multiple light sources with different L_B values are used in the operating light:

t_max = 10⁶/L_B

where

Method based on operating light test results

Measure L_B in accordance with IEC 62471:2006 within an effective angular subtense, α_eff, of 0,011 rad using a measurement distance of 700 mm and an aperture stop with a diameter, D, in the range of 7 mm to 30 mm.

Perform measurements with the operating light set at maximum light output. If the operating light has multiple operating modes with different relative spectral distributions (e.g. white light mode and mode intended for use while handling light-activated restorative materials, or white light modes with different correlated colour temperatures), perform measurements in each operating mode with the operating light set at maximum light output.

If L_B does not exceed 10 000 W/m²/sr for any of the operating modes, the risk group classification of the operating light for retinal blue light hazard (L_B) is not greater than Risk Group 1, fulfilling the requirement specified in 4.1.10.

If L_B exceeds 10 000 W/m²/sr for any of the operating modes, the risk group classification of the operating light for retinal blue light hazard (L_B) is greater than Risk Group 1, and the requirement specified in 4.1.10 is not met.

NOTE 1 The specification of α_eff = 0,011 rad, corresponds to the conditions specified in IEC 62471:2006 for evaluating for Risk Group 1 classification for retinal blue light hazard. Since evaluation for Risk Group 1 is sufficient to verify compliance with 4.1.10, measurements using other values of α_eff specified in IEC 62471:2006 do not need to be made.

NOTE 2 If the classification of operating light is determined to be not greater than Risk Group 1 by this method, the actual classification can be either exempt group or Risk Group 1.

Calculate t_max using the following formula:

t_max = 10⁶/L_B

where

Additional information on performing this test method is provided in informative Annex A.

Use the test set-up as described in 6.3.1.

Measure the radiant heat using a calibrated radiometer with an acceptance aperture of not more than 30 mm diameter and an adequate spectral responsivity in the wavelength region from 300 nm to 2 500 nm.

The test shall be conducted with the light beam directed perpendicularly onto the sensor. Measure at the point with the maximum of illuminance E_v,max.

Use the test set-up as described in 6.3.1 with a calibrated spectroradiometer having adequate responsivity over the spectral range 400 nm to 515 nm and an acceptance aperture diameter of 10 mm to 20 mm. Adjust the operating light to the setting intended for use while handling light-activated restorative materials and adjust the illuminance to the maximum level in this setting, if applicable. Position the detector at the point of maximum irradiance with the detector normal to the incident light.

Measure the spectral irradiance from 400 nm to 515 nm at uniform wavelength intervals of not more than 5 nm. Calculate the camphorquinone-weighted irradiance using the following formula:

where

Determine whether the calculated value for E_e,CQ meets the requirement given in 4.1.13.

Documents shall be provided containing at least the information as specified in the following subclauses.

The following information shall be provided by the manufacturer:

a) step-by-step procedures for the operation and routine maintenance of the operating light, including illustrations showing the location of each control and other features relating to safety;

b) the intended operating distance;

c) reprocessing instructions (applicable cleaning, disinfection and sterilization processes) in accordance with ISO 17664-1 and ISO 17664-2;

d) specification for replacement of the light source (e.g. lamp or bulb) if light source is replaceable;

e) if the classification of the operating light is greater than exempt group for actinic UV exposure for skin and eye (4.1.8), near-UV exposure for the eye (4.1.9) or retinal blue light hazard exposure (4.1.10), a statement indicating each risk group classification in excess of exempt group and respective guidance on safe operating procedures, including the most restrictive permissible exposure duration (t_max) if the centre of the operating light beam is directed in the viewer’s eyes (based on the calculated values per 6.3.9, 6.3.10 and 6.3.11);

f) information about the potential need of protection either for eye or face, or both, for individuals with sensitivity to strong light sources, such as those taking a photosensitizing drug that can accumulate in eye tissue and those with certain eye diseases or photodermatoses.

The following information shall be provided by the manufacturer:

a) information and instructions on assembly and installation, including space requirements, mounting requirements and electrical supply requirements;

b) service documentation, including wiring diagram;

c) overall movements;

d) range of illuminance (if illuminance is continuously adjustable) or illuminance levels (if illuminance has discrete settings), expressed in lux;

e) specification of colour fidelity index (R_f);

f) specification of correlated colour temperature (CCT);

g) information on whether the operating light has a setting that is compatible with light-activated restorative materials, conforming to 4.1.13;

h) dimensionally scaled diagram showing typical illuminance pattern contour lines corresponding to 10 %, 50 % and 75 % of the maximum illuminance when the operating light is set to its maximum illuminance setting;

i) if the operating light is designed to be used at a target distance other than 700 mm, additional performance specifications per items d), e), f) and h) at the intended operating distance.

The accompanying documents shall be checked to ensure that all the information specified in 7.2 and 7.3 is provided.

Operating lights shall be packaged for transportation in such a way that no damage can occur during anticipated transport conditions.

Component parts shall be specifically identified on the outside to facilitate correct assembly.

The marking on the outside of the operating light shall include the following marking if the risk group classification for actinic UV hazard for skin and eye according to 4.1.8 or near-UV hazard for the eye according to 4.1.9 is Risk Group 1:

NOTICE

UV emitted from this product

Graphical symbols used for marking, operating controls and performance shall be in accordance with ISO 9687 and ISO 15223-1.

1. 
   (informative)
   
   Additional information for retinal blue light hazard exposure test method

This informative annex provides additional information that may be optionally applied to perform the retinal blue light hazard exposure test method based on operating light test results specified in 6.3.11.3.

• 1. Background

IEC 62471:2006 specifies two methods for radiance measurements: a standard method and an alternative method. The alternative method specified in IEC 62471:2006, 5.2.2.2 is applied in this annex to determine the maximum blue light weighted radiance of the operating light at a distance of 700 mm. This method is based on irradiance measurements and a field stop to control the field of view and offers the advantage that the same measurement system used for other test methods in this standard can be used with minor modifications.

• 1. Test setup and measurement equipment
     1. Test setup

Follow the test setup specifications in 6.3.1. Mount either the dental operating light or the radiometric instrument (A.2.2.1) on an x,y translation stage oriented normal to the z-direction (i.e., direction of the beam) to allow positioning of the radiometric instrument at various points within the illuminance pattern of the dental operating light at a distance of 700 mm from the dental operating light.

As specified in 6.3.11.3, perform measurements with the operating light set at the maximum light output. If the operating light has multiple operating modes with different relative spectral distributions, perform measurements in each operating mode with the operating light set at maximum light output.

• • 1. Measurement equipment
       1. Radiometric instrument

The radiometric instrument consists of a radiometer or spectroradiometer, an integrating sphere or cosine corrected diffuser, and optionally a fibre-optic cable. Use a radiometer or spectroradiometer that meets the requirements specified in IEC 62471:2006, 5.2.1, having adequate responsivity over the spectral range 380 nm to 700 nm. Position an integrating sphere or cosine corrected diffuser in front of the radiometer or spectroradiometer to ensure that light from all angles is appropriately factored into measurements. A fibre-optic cable may be used to connect the integrating sphere or cosine corrected diffuser to the radiometer or spectroradiometer. Other radiometric instruments that meet the requirements specified in IEC 62471:2006, 5.2.1, having adequate responsivity over the spectral range 380 nm to 700 nm, may be used instead. The acceptance aperture of the radiometric instrument shall have a diameter between 7 mm and 30 mm. The measurement distance (700 mm) is determined from the external most forward part of the operating light to the acceptance aperture of the radiometric instrument (Figure A.1).

NOTE A more accurate measurement of maximum E_B can be made using an acceptance aperture having a smaller diameter (7-10 mm) compared to using a larger diameter (20-30 mm) if the illuminance pattern is not uniform near the maximum E_B. However, using a smaller diameter acceptance aperture can require greater effort to locate the maximum E_B.

• • • 1. Imaging Luminance Measurement Device (ILMD)

Optionally, an ILMD may be used to assist in reducing the number of iterative measurements to determine the location of the maximum E_B in the measurement plane (as described in A.3.1) and to determine the appropriate location for positioning the field stop in front of the operating light (as described in A.3.2).

NOTE It is possible to determine L_B with a calibrated ILMD using luminance image measurements and the spectral power distribution of the operating light. That method is not described in this informative annex.

• • 1. Field Stop

An essential element of the alternative method specified in IEC 62471:2006 is a field stop, which limits the light emitted from the operating light that reaches the radiometric instrument to just the light within the specified field of view, corresponding to the solid angle subtended by an effective angular subtense, α_eff. To evaluate whether the risk group classification for retinal blue light hazard of the operating light is Risk Group 1 (i.e., the highest risk group classification allowed per 4.1.10), a value of 0,011 rad for α_eff is specified by IEC 62471:2006. To limit the field of view to α_eff = 0,011 rad at a measurement distance of (700 ± 3) mm, use a field stop with a diameter of (7,7 ± 0,2) mm. An iris diaphragm can be used for the field stop, adjusted to the specified diameter. Table A.1 summarizes the test set-up parameters for performing the measurements.

Table A.1 — Operating light retinal blue light hazard exposure test parameters for Risk Group 1

NOTE The test method for actinic UV hazard exposure for the skin and eye (6.3.9) and the test method for near-UV hazard exposure for the eye (6.3.10) do not require a field stop since the requirements associated with those test methods are based on irradiance rather than radiance.

Mount the field stop perpendicular to the optical axis and as close as practical to the external most forward part of the operating light, preferably within 5 mm, on an x,y translation stage oriented normal to the z-direction (i.e. direction of the beam) with coordinate positioning accurate to ±1 mm or less to allow positioning of the field stop at various points directly in front of the dental operating light.

If necessary, mount a stationary mask adjacent to the field stop to block light from passing around the outer edges of the field stop and reaching the radiometric instrument. If needed, use a stationary mask with a sufficiently large aperture and mounted in a position to permit all light within the field of view established by the field stop to reach the radiometric instrument.

Figure A.1 depicts a schematic of the test setup with the field stop and optional stationary mask.

Dimensions in millimetres

Key

Figure A.1 — Schematic diagram of the test setup with field stop and optional stationary mask

• 1. Measurement method
     1. Determination of the location of the maximum blue light weighted irradiance

With the field stop and optional stationary mask removed, measure the spectral irradiance, at coordinates in the measurement plane (i.e., the plane normal to the beam direction at 700 mm from the operating light) not more than 5 mm apart over a sufficiently large area to determine the location of maximum E_B. E_B is calculated from the spectral irradiance, E_λ(λ), using the following equation:

where E_B is expressed in W/m², E_λ (λ) is expressed as W/m²/nm, B(λ) is the blue light hazard weighting function (unitless) specified in IEC 62471:2006, and Δλ is the bandwidth expressed as nm.

Fix the position of the radiometric instrument relative to the operating light with the acceptance aperture at the location of maximum E_B.

NOTE 1 The objective of this step is to position the radiometric instrument at the location of the maximum blue light weighted irradiance in the measurement plane. In the next step (A.3.2) the maximum blue light weighted radiance is determined based on irradiance measurements with the field stop in place and the radiometric instrument at the position determined in this step.

Alternatively, irradiance, E, or illuminance, E_v may be measured instead of E_B, in which case fix the position of the radiometric instrument relative to the operating light at the location of the maximum value of the alternative quantity measured.

NOTE 2 A consequence of the requirement for chromatic uniformity (4.1.4) is that the locations of maximum E_B, E and E_v are essentially coincident.

NOTE 3 Since the maximum illuminance in the measurement plane is determined in 6.3.2, positioning the radiometric instrument at the location of maximum illuminance determined in 6.3.2 can eliminate the need to repeat the iterative search for the position of the maximum E_B described in this subclause.

Optionally, an ILMD may be used instead to determine the location of the maximum E_B in the measurement plane and subsequently to determine the position of the field stop in A.3.2. Determine the location of the maximum luminance using the ILMD as described in 6.3.2, then remove the screen and position the ILMD at the position of maximum luminance and directed toward the operating light.

• • 1. Measurement of blue light weighted irradiance

If an ILMD is not used, mount the field stop and stationary mask (if using) as specified in A.2.3 and depicted in Figure A.1. Keep the radiometric instrument fixed in the position relative to the dental operating light determined in A.3.1. Measure the blue light weighted irradiance, E_B, with the field stop positioned at coordinates in the x,y-plane not more than 5 mm apart over a sufficiently large area to determine the location of maximum E_B.

A sheet of black drawing paper or other non-reflecting material may be used to help find the location of the field stop that results in the maximum E_B at the acceptance aperture of the radiometric instrument by placing the paper just in front of the acceptance aperture. As the field stop is repositioned, measurements can be made when greater illuminance is observed on the paper in the location of the acceptance aperture (removing the paper to make measurements), whereas no measurements need to be made when less illuminance is observed on the paper in the location of the acceptance aperture.

Use a spacing of less than 5 mm between measurements near the maximum measurement if the E_B measurement at any point adjacent to the maximum E_B is less than 80% of the maximum E_B.

Record the maximum value of E_B with the field stop in place.

If an ILMD is used, record an image of the operating light’s emitting surface with the ILMD positioned as indicated in A.3.1 . Determine the location of the maximum luminance emitted by the operating light from the luminance distribution image taken by the ILMD. Install a field stop centered at the location in front of the operating light at the location of the maximum luminance. Replace the ILMD with the radiometric instrument, ensuring that the position of the acceptance aperture of the radiometric instrument precisely aligns with the position of the ILMD aperture. Make measurements with the field stop at the location of maximum illuminance and at several nearby points in the x- and y-directions. Record the maximum value of E_B measured with the field stop in place.

• 1. Calculation of retinal blue light weighted radiance and permissible exposure duration

Following IEC 62471:2006, 5.2.2.2, calculate the blue light weighted radiance, L_B, using the maximum value of E_B recorded in A.3.2, the measurement distance (700 mm) and the field stop diameter (7,7 mm):

Where L_B is expressed as W/m²/sr and E_B is expressed as W/m².

Using the calculated value for L_B and the criterion specified in 6.3.11.3, determine whether the requirement specified in 4.1.10 is fulfilled.

Calculate permissible exposure duration as specified in 6.3.11.3.

1. 
   (normative)
   
   Normalized absorbance of camphorquinone

Table B.1 provides the normalized absorbance of camphorquinone at 1 nm intervals for use in calculating the effective irradiance weighted against the spectral absorbance of camphorquinone, as specified in 6.3.13. Linear interpolation may be used if spectral irradiance measurements are made with smaller wavelength intervals.

Table B.1 ― Normalized absorbance of camphorquinone

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