Nominal Ocular Hazard Distance (NOHD)
Nominal Ocular Hazard Distance (NOHD) is the distance from the source at which the intensity or the energy per surface unit becomes lower than the Maximum Permissible Exposure (MPE) on the cornea and on the skin.
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The laser beam is considered dangerous if the operator is closer to the source than the NOHD. |
The following tables provide the NOHD values for each sensor model and laser class, assuming continuous operation of the laser. As a configurable device, a sensor lets you set the laser exposure (laser on-time) independently of the frame period (total cycle time for data acquisition). Continuous operation of the laser means that the laser exposure is configured to be identical to the frame period, which is also referred to as 100% duty cycle. However, in many applications the laser exposure can be smaller than the frame period (less than 100% duty cycle), thereby reducing the NOHD. The tables therefore show the worst-case NOHD. Exposure time is greater than 10 seconds. For longer exposure times, see IEC 60825.
The following table provides NOHD values for current hardware versions of sensors.
|
Model |
Laser Class |
Wavelength (nm) |
Class I NOHD (mm) | Class II NOHD (mm) |
|---|---|---|---|---|
|
and |
2 |
660 (red) |
700 | - |
|
3R |
660 (red) |
3350 | 1350 | |
|
2350C |
3B | 808 (NIR) | 19750 | 7700 |
|
2375C |
3B | 808 (NIR) | 13777 | 5375 |
|
2180D 2380D |
2 |
660 (red) |
1300 | - |
|
3R |
660 (red) |
4750 | 1850 | |
|
2410A 2420A |
3R |
405 (blue) |
1900 | 750 |
|
2430A 2440A |
2 |
660 (red) |
700 | - |
|
3R |
660 (red) |
3300 | 1300 | |
| 3B | 660 (red) | 6650 | 2600 | |
|
2430A 2440A |
2 |
405 (blue) |
550 | - |
|
3R |
405 (blue) |
2400 | 950 | |
|
3B |
405 (blue) |
6400 | 2500 | |
|
2450A |
2 |
405 (blue) |
550 | - |
|
3R |
405 (blue) |
2400 | 950 | |
|
3B |
405 (blue) |
8000 | 3150 | |
|
2490A |
2 |
660 (red) |
1300 | - |
| 3R |
660 (red) |
4750 | 1850 | |
|
2510A 2512A 2520A 2522A 2530A |
2 | 405 (blue) | 550 | - |
| 2513A | 3B | 405 (blue) | 19650 | 7650 |
|
2540A 2550A |
2 | 405 (blue) | 600 | - |
| 3R | 405 (blue) | 2950 | 1150 | |
| 3B | 405 (blue) | 6400 | 2500 | |
|
2540A 2550A |
2 | 660 (red) | 550 | - |
| 3R | 660 (red) | 2950 | 1150 | |
| 3B | 660 (red) | 5500 | 2150 | |
|
2610A |
2 | 405 (blue) | 1200 | - |
| 3R | 405 (blue) | 6150 | 2400 | |
| 3B | 405 (blue) | 35500 | 13850 | |
|
2618A |
3R | 405 (blue) | 2950 | 1150 |
| 3B | 405 (blue) | 9100 | 3550 | |
|
2629A |
2 | 405 (blue) | 600 | - |
| 3R | 405 (blue) | 3000 | 1200 | |
| 3B | 405 (blue) | 8000 | 3150 | |
|
2629A 2630A 2640A |
2 | 660 (red) | 650 | - |
| 3R | 660 (red) | 3050 | 1200 | |
| 3B | 660 (red) | 6850 | 2700 | |
|
2630A 2640A 2650A 2670A |
2 | 405 (blue) | 650 | - |
| 3R | 405 (blue) | 3050 | 1200 | |
| 3B | 405 (blue) | 8000 | 3150 | |
|
2690A |
2 | 660 (red) | 700 | - |
| 3R | 660 (red) | 2750 | 1100 |
The following table provides NOHD values for older hardware version sensors.
|
Model |
Laser Class |
Wavelength (nm) |
Class I NOHD (mm) | Class II NOHD (mm) |
|---|---|---|---|---|
|
2120A to C, 2320A to C 2130A to C, 2330A to C 2140A to C, 2340A to C 2150A to C, 2350A to C |
2M |
660 (red) |
259 | 103 |
|
3R |
660 (red) |
900 | 358 | |
|
3B |
660 (red) |
5759 | 2292 | |
|
2350A |
3B |
808 (NIR) |
19750 | 7700 |
|
2170A to C, 2370A to C |
2M |
660 (red) |
251 | 100 |
|
3R |
660 (red) |
875 | 348 | |
|
3B |
660 (red) |
3645 | 1451 | |
|
2375A |
3B |
808 (NIR) |
13777 | 5375 |
|
2180A to C, 2380A to C |
2M |
660 (red) |
245 | 97 |
|
3R |
660 (red) |
859 | 342 | |
|
3B |
660 (red) |
2645 | 1052 | |
|
2410A 2420A |
2M |
405 (blue) |
259 | 103 |
|
3R |
405 (blue) |
1300 | 500 | |
|
2430A 2440A |
2 |
660 (red) |
670 | - |
|
3R |
660 (red) |
3340 | 1330 | |
| 3B |
660 (red) |
6661 | 2598 | |
|
2450A |
2 |
405 (blue) |
559 | - |
|
3R |
405 (blue) |
2794 | 1075 | |
|
3B |
405 (blue) |
9433 | 3755 | |
|
2490A |
2 |
660 (red) |
1310 | - |
| 3R |
660 (red) |
4700 | 1850 |