Optical Measurement | Light Measurement | Remote Sensing
High-Speed System for Display Tests in Production
WP512 Imaging Spectral Colorimeter
All-in-One Imaging Colorimeter with Integrated Spectroradiometer
The Westboro Photonics WP512 is an imaging spectral colorimeter that combines a fast 12.3 Megapixel tricolour CMOS sensor (RGB filtered) with a reference spectroradiometer. The WP512’s forte is in the production line testing of displays and lighting products, where its high speed 2D measurements are combined with spectroradiometric colour accuracy. With a wide assortment of EF-mount lenses available, the WP512 is configurable for measurements of any display size, from micro-displays to smartwatches, tablets, TVs or even cinema walls. For display view angle measurements out to ±80°, we offer the unique conoscopic lens accessory. Also available is the XR1 near eye display (NED) lens that has been purpose designed for testing wearable displays that are used in augmented reality (AR) and virtual reality (VR) applications.
Features
Measurement Capabilities
The following photometric parameters can be measured using a WP512 imaging spectral colorimeter:
- Spatial luminance (candelas per square meter, cd/m2)
- Spatial illuminance (lux, lx)
- Source luminous intensity (candelas, cd)
- Spot spectral radiance (W/sr.m2.nm)
- Spatial chromaticity (CIE xy, u’v’)
- Spatial correlated colour temperature, CCT (Kelvin, K)
- Spatial radiance (W/m2) with optional radiometric filter
Matched Lenses
Each colorimeter has a lens that is matched to the sensor resolution and size, providing optimally crisp and clear images. By matching a lens to a particular sensor, the images created using a Westboro colorimeter can be of a higher quality that supposedly higher resolution cameras without matched lenses. The WP512 supports both manual and electronic lenses, with focal length between 24 and 100mm. Electronic control of lens focus and iris position offers improved accuracy, precision and convenience for all applications. Microscope lenses are available for pixel-level analysis, while a near-to-eye (NED) lens is also available for testing the displays on wearable near-eye AR/VR devices. A conoscopic lens is also available that allows for the view angle performance of a display to be measured.
Display View Angle Testing
The available conoscopic lens accessory enables viewing angle measurements of flat panel displays and backlights up to ±80°. In addition, the system provides 0.05° resolution and 0.0001 cd/m2 photometric sensitivity.
AR/VR Display Testing
The XR1 is a periscopic near eye display (NED) lens that has been purpose designed for testing wearable displays that are used in augmented reality (AR) and virtual reality (VR) applications. This lens can be fitted to the WP6E, WP6ES and WP512 series of imaging colorimeters or imaging spectral colorimeters for measurements of luminance and colour. The periscope design ensures the lens readily fits into the final assemblies of glasses, headsets and helmets. Under different stimuli, human visual accommodation results in varying pupil diameters. Therefore, the entrance pupil aperture is adjustable from 1.5 to 4.0mm.
Spectrometer Option
The WP512 benefits from automatic colour correction and radiometric transfer courtesy of an integrated spot spectroradiometer. The instrument design optimises throughput and sensitivity by sending all the light to either the camera or to the spectroradiometer, resulting in significant takt time improvements when low light measurements are required.
Key to the WP512’s unique capability is the high-speed linear translation stage. The stage has multiple positions for imaging light with the RGB camera or with the spectroradiometer. In addition, there is standard filtering up to ND1 in the RGB camera path and up to ND2 in the spectrometer path. Low luminance measurements are crucial for takt time optimisation in many production scenarios. Having higher throughput, the WP512 is two times faster at the bottleneck measurements than comparable beam-splitter solutions that share the light with two or more focal planes. The neutral density filter options accommodate a wide range of light measurements. Users can measure very bright scenes; or attenuate to increase the optimal exposure time. For example, although the camera and spectrometer can have sub-millisecond exposure times, a display modulated at 30Hz may be best measured at exposures of 33.3ms. Additionally, the method has very low polarisation dependence and minimal chromatic and geometrical distortion, both critical parameters of measurement accuracy.
Conveniently, when the camera is imaging, the spectrometer is shuttered and vice-versa. In this way, frequent dark measurement correction is available in production without affecting takt times.
Capable Software
Photometrica® software and optional software packages provide extensive options for measurement and analysis. The software development kit (SDK) allows for the creation of fully customised solutions using built-in scripting or external control.
Accredited Calibrations
Westboro Photonics is an ISO/IEC 17025:2017 accredited calibration laboratory, being the first company in the world to be accredited for the calibration of imaging light meters, as distinct from spot photometers.
Applications
The Westboro Photonics WP512 is an imaging spectral colorimeter that combines a fast 12.3 Megapixel tricolour CMOS sensor (RGB filtered) with a reference spectroradiometer. The WP512’s forte is in the production line testing of displays and lighting products, where its high speed 2D measurements are combined with spectroradiometric colour accuracy. As with any 2D imaging colorimeter, the WP512 provides for vastly increased productivity compared with ‘spot’ luminance meters.
The WP512 is suitable for measuring any type of flat panel display, from micro-displays to smartwatches, tablets, TVs or even cinema walls. It is also suitable for testing the lit area uniformity of lighting products and for performing the projected beam pattern analysis of lamps and LEDs.
The WP512 can be configured by the user to measure the view angle performance of a display using the conoscopic lens accessory. Also available is the XR1 near eye display (NED) lens that has been purpose designed for testing wearable displays that are used in augmented reality (AR) and virtual reality (VR) applications.
Please note that the WP512 is not recommended for testing the luminance and colour of small lit objects, for example backlit switches and controls in automotive and avionics applications. For object luminance measurements, you should use a WP6 series imaging colorimeter.
WP512 imaging spectral colorimeter with XR1 near-to-eye lens.
WP512 imaging spectral colorimeter with XR1 near-to-eye lens, top view.
WP512 imaging spectral colorimeter with conoscopic lens.
WP512 imaging spectral colorimeter with conoscopic lens. Display view angle testing.