DE2328982A1 - Vehicle headlamp function monitor - with integral light cell in reflector socket to measure lamp output - Google Patents

Abstract

Each headlamp is fitted with a light cell either in a separate fitting to the bulb, or positioned on a window in the side of the reflector. The cell is directed at the filament and is coupled to a twin stage emitter coupled amplifier which activates an alamr when the lamp intensity falls below a set value. This gives rapid indication of lamp failure or blackened bulbs. The cell is press fitted within the reflector rear extension socket, to be easily replaceable.

Description

SWF special factory for car accessories Gustev ^τ Ιά: ι GmbH. , 712 Bietigheira

α i ₂ i

PAT / j / Vo / Wi 4.6.1973

Device for monitoring lamps in vehicle lights, in particular in Pay attention to the motor vehicle

The invention relates to a device for monitoring of lamps in vehicle lights, in particular in vehicle lights.

It is known to switch on lamps in motor vehicles monitored by not turning on control lights on the dashboard. However, that is still not sure the turned on !. Lamps actually too burn. That is why light has already been branched off from the jecUu lamp and transmitted via a light guide rod or via optical fibers to a display panel on the dashboard (e.g. DT-OS 1 912 785). Such surveillance but includes only the aroused and not aroused state the lamp.

Often, however, there is an age-dependent blackening or one Pollution of the Lainpan in the motor vehicle aiii ", whereby the required minimum current is fallen below, v.x by other road users are endangered · (Lon.

409881/0562

- 2 - A 12 I67

The purpose of the invention is to increase road safety to contribute. It is the object of the invention to monitor lamps in vehicle lights to determine whether they emit a prescribed minimum luminous flux. this is achieved according to the invention in that a photosensitive Element is arranged in the vicinity of each lamp that this element has a display means Evaluation circuit (Fig. 2) controls and that the evaluation

circuit is dimensioned in such a way that when the luminous flux falls below a prescribed minimum value of the relevant Lamp responds.

The invention will now be based on an exemplary embodiment explained in more detail. Show it

Fig. 1 shows a vehicle light with a photo resistor attached to the reflector and

2 shows a circuit arrangement of an evaluation circuit controlled by the photoresistor.

In FIG. 1, an incandescent lamp 12 is inserted into a reflector 11, the filament 13 being located iia the focal point of the reflector Ii. The reflector 11 is provided with a sleeve ik in which a photoresistor 15 is arranged. namely at the end of the incandescent lamp 12 applied. The central axis of the sleeve Ik and the photoresistor 15 is aligned with the filament 13. The photoresistor Ip thus receives an optimal amount of light without it being able to be significantly influenced by external light. In addition, the end of the sleeve ik facing the incandescent lamp 12 can be covered by a transparent cap 16 that is matched to the light spectrum of the incandescent lamp 12 in order to further reduce the influence of external light. The reflector Ii and the sleeve 14 are preferably made in one piece from plastic.

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-3 - ^{A 12}

In a modification of FIG. 1, the photoresistor can also be arranged outside the reflector, with an insulating tube and a blackened light passage would be necessary,

If the luminous flux emitted by the incandescent lamp 12 falls below a minimum value (for example kkO lumens for an incandescent lamp with an output of 21 V /), this is detected by the photoresistor 15, which controls the evaluation circuit shown in FIG. 2 accordingly.

In Fig. 2 a two-stage, galvanically gel- ^ ppelter transistor amplifier is shown in emitter circuit, the transistors Tl, T2, emitter resistors R3, Rk, a collector resistor R3 for the first transistor Tl, a control lamp KL arranged in the collector circuit of the second transistor T2 and a Has base voltage divider for the first transistor Ti. The base voltage divider consists of a parallel circuit connected between the base of the transistor Tl and the negative pole -Ü _{R of} the supply voltage source, consisting of the photoresistor 15 and a variable resistor Rl and also of a resistor R2 _{t located between the base de3 transistor Tl and the base point 0}

With sufficient luminous flux, the photoresistor 15 is low ohinig, do that the transistor Tl is controlled and loitrnd consequently the transistor T2 is blocked. The control lamp KL, which is also by a buzzer or something else Display means replaces i; erdeii can, remains dark. Sinks If the luminous flux falls below a prescribed minimum value, the transistor Tl is blocked because the resistance value of the photo resistance 15 increases. The transistor T2 therefore becomes conductive, and the control lamp KL lights up. This monitoring is of course only effective if the Light bulb is switched on.

With the variable resistor Rl, the response

409881/0562

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sensitivity of the evaluation circuit and the tolerances the photoresistors are compensated.

Photo resistors that are functionally assigned to the same lamps, for example the left and right brake lights, can act on the same display means because the associated light bulbs are usually replaced together will. ·

It is also possible to use an arrangement similar to that described for monitoring a prescribed Maximum luminous flux to be provided.

409881/05 62 " ⁵

Claims (8)

F-special factory for Ajitpzjubeliöi »jöuptay Qavj GmbH., 712 Bietigheim - 5 - A 12 167 ΡΛΤ / j / Vo / Vi 4.6.1973 Claims 1 / device for monitoring lamps in vehicle lights, in particular in motor vehicle lights, thereby marked, that a photosensitive element (15) is arranged in the vicinity of each lamp (12) that this element has an evaluation circuit having a display means (Fig. 2) controls and that the evaluation circuit is dimensioned such that it falls below a prescribed Liohtetromra minimum value of the concerned Lamp responds. 2. Device according to claim 1, characterized in that the center axis of the photosensitive element on the Burning body (13) of the lamp is aligned. 3. Device according to claim 2, characterized in that the photosensitive element in a sleeve (14) on whose end facing away from the lamp is arranged. k. Device according to claim 3, characterized in that the sleeve (14) is part of a reflector for the lamp. 5 device according to claim 3 or k, characterized in that the end of the sleeve facing the lamp is covered by a transparent cap (16) tailored to the light spectrum of the lamp, 6. device naoh einsm of claims 1 to 5, characterized 409881/0562 " ⁶ " Il s * ". S- _e « £. J * '. < A i2 167 characterized in that the evaluation circuit by a two-stage, galvanically coupled transistor amplifier (Ti, T2) is formed in the emitter circuit that the light-sensitive element between the base of the first transistor (Tl) and the one connected to the collectors Supply voltage pole (-U ") is and that the display means (KL) is arranged in the collector circuit of the second transistor (T2). 7. Device according to claim 6, characterized in that the light-sensitive element, a variable resistor (Rl) is connected in parallel. 8. device nr ~ ch one of claims 1 to 7, characterized characterized in that the light-sensitive elements, which are functionally assigned to the same lamps, act on the same display means « 9. Device according to one of Claims 1 to 8, characterized in that characterized in that an analog arrangement for monitoring a prescribed Liohtstromhöohstwert is also provided. 409881/0562 Le e rs e it