From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Letter to The Safelight Motor Lamp Co. Ltd. regarding the principles of headlamp design to prevent dazzle.
| Identifier | ExFiles\Box 61a\2\ scan0498 | |
| Date | 31th January 1935 | |
| c. to Cx.{Major Len W. Cox - Advertising Manager} Clerk. Hs{Lord Ernest Hives - Chair}/Wst.9/MA. 31st January, 1935. The Safelight Motor Lamp Co.Ltd., 18A Newington, Liverpool. For the attention of Mr.E.Jones. Dear Sir, We have now had an opportunity of carefully considering the Safelight headlamp as shewn to the undersigned. The principle involved must necessitate at least 50% of the available light being deflected downwards on the road and it would mean very careful adjustment to prevent the lamps from dazzling with the rear seats loaded when the lamps had been set correct for long distance dazzle unloaded. Conversely if the lamps were set with the rear loaded too much light would be deflected on to the road with car unloaded. For high speed driving one must be able to see clearly at a considerable distance and if objects are clearly visible at that distance it obviously follows that your lamps would dazzle oncoming drivers. There is no royal way in our opinion to obviate dazzle when meeting cars other than a change in the focal length of the beam or a dipped reflector. We must not penalize maximum driving light but reduce it when occasion demands. | ||