A scientific study on the effects of Ambilight in flat-panel displays
Based on internal tests Philips has formulated and communicated claims about positive effects of Ambilight. The TUe has been requested to scientifically validate these claims. The experiments conducted by the TUe in a tightly controlled environment with a low overall room lighting level, using balanced assessment methodologies, show the following results:
In a (dark) home cinema room lighting condition (7 lux room lighting level) Ambilight can reduce eye strain in 60-90% of the people dependent on the Ambilight setting and the nature of the film/programme. Ambilight, in particular the active Ambilight- relaxed mode can improve the overall viewing experience, the degree of which depends on the nature of the programme. The active Ambilight – relaxed setting also gives the possibility to add a new overall positive psycho-fysiological experience to certain types of film/ programmes.
Philips Consumer Electronics (Philips) has conducted internal “viewing” tests with test persons in Germany, Belgium, USA and China using a flat TV 42PF9986 equipped with an Ambilight system.
Test protocol and questionnaires used in the Hamburg and Brugge experiments were made available to the Technical University Eindhoven (TUe) research team as well as the test results. Furthermore Philips indicated that similar tests were conducted in the USA and China. Based on these tests Philips has formulated (and communicated) the following claims about Ambilight:
- Viewing with Ambilight is experienced by most viewers as more pleasant and comfortable for the eyes than without it
- Ambilight is more relaxing for the eyes (and less tiring for the body)
Philips approached the TUe (Chair: Lighting Science, Engineering and Design of Prof. Dr. Ir. Begemann, Faculty of Architecture) via the Stichting Onderzoek Licht en Gezondheid (SOLG) to conduct a scientific study to verify the claims. Prof. Begemann has both the facilities and measuring techniques/tools to conduct vision- and visual – assessment studies in addition to know-how and equipment to measure bio- physical as well as psychological parameters. The TUe used the test facilities and test protocols* adapted to the specific requirements for the Ambilight research.
* Test protocols developed by TUe can not be used by Philips, WMC or other parties without written permission from Tue
2 Test facilities and –protocols
All viewing experiments with test persons were conducted in a test room measuring 3.6 * 4.8 m with simple furnishing (figure 1). The distance wall - Ambilight strip was 15 cm, which resulted in a relatively large ‘light footprint’ on the wall.
Figure 1, the test room (dimensions in mm)
With this set-up a “neutral” living room condition with representative viewing distance was created. Walls and ceiling were soft white, carpeting was even blue/grey to avoid any “visual distraction“. The test person sat on a comfortable couch in front of the TV, while the researcher sat next to this couch at a small desk with a laptop.
With a dimmable halogen up lighter the overall room lighting level could be set from 0- 200 lux.
The TV set used was a regular Philips 42PF9986. The only modification made at the explicit request of the TUe was in the Ambilight remote control system so that it was possible to remotely change Ambilight settings without onscreen display of the different Ambilight settings and the chosen setting.
In the internal Philips experiments this was not done so that all test persons were influenced by seeing this info (further reducing the scientific value of their judgement).
To scientifically validate the Ambilight viewing effects/experience, stills as well as film scenes were used. They have been selected to enable the best possible detection of an effect. Still pictures by their nature/composition can enhance “focussing” the eyes on a specific area (pictures 1-5 , see below) or the extreme opposite, “scanning“ the whole screen because of the abundance/diversity of visual information
Three different film scenes were used to assess the effects of Ambilight on dynamic viewing experience and eye strain (see below).