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).
Brochure for Carl Zeiss Jena auto headlights, detailing their design, anti-glare features, and various models.
| Identifier | ExFiles\Box 61a\1\ scan0274 | |
| Date | 1st February 1927 guessed | |
| Page 2 CARL ZEISS JENA Auto 94 Engl. When motoring at night, the safety of the car and its occupants depends in a great measure upon the lighting equipment which it carries. It is entirely in the interest of motorists to furnish their cars with the very best means of lighting which modern technique and the resources of the industry have been able to evolve. In this respect the Zeiss Projector Headlights designed for acetylene and electricity satisfy the most exacting requirements. Besides projecting a strong beam of light a great distance ahead, they furnish a liberal outward spreading light and thereby command the whole of the track with a good and uniformly bright light. An illumination of this kind can only be obtained by optical means. The optical device which constitutes the characteristic element of the Zeiss Reflector Headlights consists in all models of a principal reflector operating in conjunction with an auxiliary reflector. The principal reflector takes the form of a deep parabolic mirror of optically worked glass of as large a diameter as the lamp in question will admit to secure the greatest lighting effect compatible with its purpose. The auxiliary reflector is a hemispherical glass mirror in the case of gas headlights and a silvered belt on the lamp bulb in the case of the electrical headlights. This auxiliary reflector is so arranged that all light which does not fall directly upon the principal reflector is thrown back upon the latter, whereby the resulting intensity is nearly doubled. A sufficient amount and quality of light is spread outwards by ground and polished glass fronts with a special form of ribbing. As this light has a spread of almost 180°, separate curve lamps can be dispensed with. The reflectors of the Zeiss headlights have a remarkably high reflecting capacity, which, unlike that of all metallic reflectors, does not deteriorate with time. The silvering at the back of the Zeiss glass reflectors is protected by several layers of coppering and varnish, in consequence of which it is not liable to be affected by moisture, gases of combustion, and such like. Hence the reflectors may, without fear of doing damage, be cleaned at any time with damp leather or linen. In order to obtain the best possible lighting effect it is very important that the filament bulb should be accurately set with respect to the focal point of the parabolic mirror. This can be done with the aid of the focusing arrangement. Using a screw-driver the set screw at the pointed end of the headlight casing should be turned back and forth until the beam of light leaves the reflector in as compact a form as possible. Page 3 CARL ZEISS JENA Auto 94 Engl. The Antiglare Device, Zeiss-Fog-Light: The extent to which the headlight can be deprived of its dazzling effect, more than any other quality, is the deciding factor of safety in the motor traffic at night. We feel that we might rightly claim to have solved this hotly debated problem in an adequate manner by the antiglare principle of the Zeiss headlights; for these not only take full cognisance of the needs of the motorist but likewise conform to the requirements of the authorities. In the large and medium sized models of the electrical Zeiss headlights the dazzling effect is cut out by pushing over the lamp bulb a yellow glass filter with partly open metal cap. By this means the dazzling light from the white projector is toned down to a mild yellow, which is more pleasant to the eye. Pedestrians and drivers of approaching cars are in no way dazzled when looking directly into this modified light. Nevertheless, the new light is exceedingly bright and penetrating, so that the driver is well able to see clearly and to recognise obstacles in good time when travelling at very great speeds. It so happens that yellow light penetrates mist and fog more effectively than white light, in consequence of which the advantages of the new Zeiss Fog Light are particularly beneficial on misty and foggy days. In the smaller electrical headlights the glare is cut out by moving the lamp forward out of the focus of the mirror. In the case of one of the medium sized models equipped with twin-filament bulbs, the antiglare effect is obtained by having the current switched from the main filament into the low watt auxiliary filament of the bulb. Design & Style: The casings of the Zeiss projector headlights are of an appropriately designed and rigid as well as pleasing form. Their closing fronts have thoroughly impervious joints and are furnished with substantial and practical locking devices. The head lamps are supplied in black enamelled or nickeled casings and fittings, and special attention has been paid to substantial workmanship and elegant appearance. For Prices see separate Price List. Zeiss Projector Head Lights are to be obtained from all reputed manufacturers and dealers in the motor trade or direct from Carl Zeiss, Jena. When buying a car ask for Zeiss Projector Lights. Page 4 CARL ZEISS JENA Auto 94 Engl. ZEISS AUTO HEADLIGHTS with fog light antiglare device, enclosed stationary lamp, and specially ribbed front glass. 5550 Fig. 1. For large cars. 5299 Fig. 2. For medium and small sized cars. The light of these lamps in dimmed by the bulb being partly covered by a yellow-coloured calotte producing a yellow light of great efficiency in misty and foggy weather. TABLE Type | Diameter of mirror in mm | Outside-diameter of casing in mm | Range in metres | Style | Codeword --- | --- | --- | --- | --- | --- ZESAP 250 (Fig. 1) Fork-attachment | 250 | 300 | 500-550 | black, black enamelled with nickel rim nickel-plated | Autvadsel Autvadsim Autvadsire ZESAP 200 (Fig. 2) Pivot-attachment | 200 | 240 | 300-350 | black, black enamelled with nickel rim nickel-plated | Autvadripo Autvadros Autvadrub ZESAPS 160 (Fig. 2) Pivot-attachment | 160 | 200 | 200-250 | black, black enamelled with nickel rim nickel-plated | Autvadre Autvadrii Autvadrime Accessories: Fork or Pivot transmission gear for operating the antiglare device adapted for two headlights. Page 5 CARL ZEISS JENA Auto 94 Engl. ZEISS AUTO HEADLIGHTS with dimming device twin-filament bulb, enclosed stationary lamp, and specially ribbed front glass. 5551 Fig. 3. For large and medium sized cars. TABLE Type | Diameter of mirror in mm | Outside diameter of casing in mm | Range in metres | Style | Codeword --- | --- | --- | --- | --- | --- ZESDOP 200 (Fig. 3) | 200 | 254 | 300-350 | black enamelled with nickel rim | Autvadzwug The light is dimmed — at considerable saving of current — by charging the auxiliary filament of the bulb. Accessories: Fig. 4. Foot switch. For dimming twin-filament bulb of type ZESDOP (Fig. 3), codeword: Autvadzwui 5556 Fig. | ||