GB2038010A - Camera with display means - Google Patents

Abstract

In a camera which is provided with display means for indicating the aperture setting, exposure time or any other control value to which the camera has been set, the optical display means (42) can also be employed to indicate the condition of switches or other components of the camera, e.g. during manufacture of the camera. As shown, a rod (50) is operable to disconnect the display means (42) from, for example, the standard electronic unit (18) and connect it to components such as switches (S1, S2, S3). A microprocessor in the camera then runs through a test programme instead of an exposure programme and displays the results at 42. <IMAGE>

Description

SPECIFICATION Camera with optical display means This invention relates to cameras of the kind having optical display means for indicating, for example, the settings of various controls.

In the manufacture of cameras, faults may occur which have to be put right. To this end, the source of the faults must first be traced. This fault tracing is the most difficult and time-consuming part of any repair work. The later a fault is discovered, the more difficult is it to locate and also repair, particularly when the camera has already been trimmed with leather or other material.

The object of the invention is to enable a fault to be traced easily, with the minimum use of materials and the minimum expenditure of time.

This is achieved, according to the invention, by providing a camera of the kind described with a device for feeding to the optical display means signals dependent upon the condition of the switches and/or other components of the camera.

As a result of this simple solution, the display of many different faults which may occur during the manufacture of a camera is made possible.

Experience has shown, in fact, that the greatest problems emanate from the electromechanical interfaces. Since according to the invention, various camera switches are monitored and their condition displayed, the invention enables the majority of faults and their location to be readily ascertained. It goes without saying that it is also possible to feed to the display means signals concerning the condition of components other than the various camera switches and so render their condition visible.

A further advantage of the invention resides in the fact that the display means present in any case to indicate the operational settings for the job to be performed, for example, the aperture setting and exposure time may be used to display signals which indicate whether the camera is working properly or is malfunctioning. In consequence, a display of faults is possible without additional space being required for the display means, a factor which is eminently significant in view of the ever-increasing miniaturisation employed in camera construction.

A further advantage of the invention lies in the fact that faults are visible at a glance. it is therefore, possible, without loss of time, to check the condition of switches and various other components during various stages of assembly of the camera. In this way, any fault which may arise can be quickly noticed and put right before further assembly of the camera makes repair difficult.

The nature of the signals used and their desired sequence is selectable according to the display means available. The term display means is intended quite generally to refer to all suitable display devices, such as liquid crystal cells, lamps, gas discharge lamps or light emitting diodes, e.g.

in segmented scales, or even indicating pointers on dials. The scales or dials themselves may be located on the outside of the camera or may even be visible in the viewfinder.

If the number of optical display means provided for the camera user is not adequate for the simultaneous display of faults, then each individual display means may be used to indicate a plurality of possible malfunctions. For this purpose, it is necessary only for it to be supplied with the corresponding condition signals in succession. If desired, one or a plurality of display means, in addition to the existing display means, may be provided especially for fault tracing.

According to an advantageous further embodiment of the invention, the device for feeding condition signals comprises a switch which may be actuated to prevent signals representing camera settings and the like being passed to the display means and to establish paths by which condition signals may be transmitted to the display means.

This further embodiment guarantees that during fault tracing, the display means indicates only the condition of switches and other components and not adjusted settings such as exposure time, diaphragm setting, distance and the like.

The device for feeding condition signals may comprise a microprocessor. Since microprocessors of extremely small dimensions can now be manufactured, this only necessitates a minimum of additional space: It is expedient for the device for feeding condition signals to comprise a microprocessor which is in any case accommodated in the camera and which processes a particular condition test programme. The microprocessors used in microprocessor-controlled cameras are generally capable of controlling more than has been controlled in the past. For this purpose, it is necessary only to have an additional test programme which is expediently stored in a programme memory contained in the microprocessor.This further development of the invention has the advantage that in addition to the switch-over device, no additional space is required, since a microprocessor which can also process the test programme does not necessarily have to be larger than a microprocessor which is in any case accommodated in the camera.

The switchover device itself may be a multipole swich or a single-pole switch with gates. This switch-over device.may include a mechanical release rod which protrudes through an aperture in the camera body or ends beneath the aperture in the camera body. In the latter case, it is possible, by introducing a small needle through the aperture, to depress the release rod which may be biassed towards the aperture and so operate the release. This aperture may be sealed when the camera is leather-trimmed.

The switch-over device itself may be electromagnetically actuated.

According to a further feature of the invention, the switch-over device may be arranged to be operated by an otherwise unutilised switch combination. In this case, no additional switch or release is required.

The switch-over device can also comprise an electronic switch.

Further advantages and features of the invention will become evident from the following description with reference to the accompanying drawings in which: Fig. 1 a is a symbolic representation of a standard electronic unit for a camera, having various conductor connections and having a symbolically illustrated switch-over device which is shown in its inoperative state; Fig. 1 b shows the arrangement of Fig. 1 a but with the switch over device actuated; Fig. 2 is a flow diagram of one embodiment of the invention; and Fig. 3 is a flow diagram of another embodiment of the invention.

Figs. 1 a and 1 b represent purely symbolically and in greatly simplified form one of the many possible circuit arrangements according to the invention.

Fig. 1 a shows on the right-hand side a display line 42 comprising three light-emitting diodes 44, 46 and 48 which serve to display the exposure time.

The light-emitting diode 44 indicates an exposure time of 1/500 sec., the light-emitting diode 46 indicates an exposure time of 1/1 25 sec.

and the light-emitting diode 48 indicates an exposure time of 1/30 sec. In the embodiment illustrated the light-emitting diode 46 indicates, when illuminated, that when the camera is triggered, the exposure time will be 125th of a second. The entire LED line 42 appears in the viewfinder of a camera.

In the top left-hand part of Fig. 1 a there is shown a mirror contact S1, a memo switch S2 and a shutter contact S3. The switch S1 is open and the switches S2 and S3 are closed. From these three switches, conductors 11, 1 2 and 13 lead to a standard camera electronic unit. This can emit signals via output conductors 1 5, 1 6 and 1 7 to actuators Al, A2 and A3.

From the camera electronic unit 1 8 extend output conductors 25, 26 and 27 of which the ends 35, 36 and 37 are connected via switch contacts 28, 29 and 30 to conductors 38, 39 and 40 which lead to the display line 42.

The switch contacts 28,29 and 30 are connected to one another by a common release rod 50 which is biassed upwardly by a spring 52.

The release rod 50 ends immediately below an aperture 53 in the camera body 54. It can be pushed downwardly by a needle inserted into the aperture 53. When the needle is removed the release rod 50 is returned by the spring 52 to its position illustrated in Fig. 1 a in which the conductors 25, 26 and 27 of the electronic unit are connected to the display line 42.

The conductors 11, 12 and 13 which connect the switches S1, S2 and S3 to the electronic unit 1 8 are also connected to conductors 21,22 and 23, the ends 31, 32 and 33 of which can be connected to the conductors 38, 39 and 40 by means of the switch-over contacts 28, 29 and 30.

When the release rod is depressed into the position shown in Fig. b, the switch contacts 28, 29 and 30 are thrown, so that they connect the conductor ends 31, 32 and 33 to the conductors 38, 39 and 40. The conductors 25, 26 and 27 from the electronic unit 1 8 are then isolated from the display dial 42 and the switch contacts associated with the switches S1, S2 and S3 are directly connected to the conductors 38, 39 and 40 and thus to the light-emitting diodes 44, 46 and 48. Since the switch contacts S1, S2 and S3 are subject to battery voltage UB and since the switch contacts S2 and S3 are closed, lightemitting diodes 46 and 48 now light up, indicating that the switches S2 and S3 are closed and that the switch S1 is open.

Fig. 2 is a flow diagram of one embodiment of the invention. On starting the camera electronic unit, a test switch 55 is monitored. If this switch has not been actuated and is thus open the microprocessor will process the standard main programme 56. When this happens, the display dial 42 will display the settings which are required when the camera is to be operated.

If, on the other hand, the test switch has been actuated and is thus closed, then the programme 57 will be processed by the microprocessor and the display dial 42 will indicate the condition of various camera switches and other components of the camera.

Another flow diagram in accordance with the invention is shown in Fig. 3. Upon operation of the camera electronic unit, the standard main programme 56 will be initially processed by the microprocessor via an OR gate 59, whereby in turn, via an assembly of output conductors, command signals will be sent out to the actuators and, via another set of output conductors, functional signals will be passed to the display dial 42.

Via the main programme, the test switch 55 is monitored via the main programme. If it has not been actuated and is thus open, then a corresponding signal will pass via the OR gate 59 to the input of the main programme.

On the other hand, if the test switch 55 has been actuated and is therefore, closed, then the test programme 57 will be switched on and processed by the microprocessor. When this happens, the functional signals will in turn, be suppressed by the switch-over device and in their stead, the condition signals will be fed to the display dial 42.

According to the programmes used, it is possible, when switching on the microelectronic unit, firstly to run through the main programme completely and only then to scan the test switch 55. It is however, also possible to have both programmes running parallel with each other.

Thus, the invention makes it possible to monitor the condition of the various camera switches and other components, both in their inoperative positions and while they are operating and to display this condition on the existing display dials.

The invention also makes it possible during assembly of the camera to have the display means monitored by automatic readers and if the display means indicate a fault, to divert the camera automatically to the repair belt.

The invention is not limited to the embodiment described. For example, a plurality of display dials, other circuitry arrangements and other functional cycles may be provided within the scope of the appended claims.

Claims (15)

1. A camera of the kind provided with optical display means for indicating the values to which various controls have been set, for example, aperture setting and exposure time, characterised by the provision of a device for feeding, to the optical display means, signals which are dependent upon the condition of the switches and/or other components of the camera.

2. A camera according to Claim 1, characterised in that the device comprises a switch-over device which, when actuated, prevents the usuai functional signals from being passed to the display means and establishes transmission paths through which condition signals are fed to the display means.

3. A camera according to Claim 2, characterised in that the device for feeding condition signals comprises a microprocessor.

4. A camera according to Claim 3, characterised in that the microprocessor is accommodated inside the camera and can process a condition test programme.

5. A camera according to Claim 4, characterised in that the test programme is stored in a programme memory.

6. A camera according to one of Claims 3 or 4, characterised in that the test programme is stored in a programme store contained in the microprocessor.

7. A camera according to any one of Claims 2 to 6, characterised in that the switch-over device comprises a multipole switch,

8. A camera according to any one of Claims 2 to 6, characterised in that the switch-over device comprises a single pole switch with gates.

9. A camera according to any one of Claims 2 to 8, characterised in that the switch-over device contains a mechanical release rod.

10. A camera according to Claim 9, characterised in that the release rod protrudes thrniigh an aperture in the camera body.

11. A camera according to Claim 9, characterised in that the release rod terminates beneath an aperture in the camera body.

12. A camera according to any one of Claims 2 to 11, characterised in that the switch-over device is electromagnetically actuated.

1 3. A camera according to any one of Claims 2 to 12, characterised in that switchover device is arranged to be operated by an otherwise unutilised combination of switches.

14. A camera according to any one of Claims 2 to 13, characterised in that the switch-over device comprises an electronic switch.

15. A camera according to any one of Claims 2 to 13, characterised in that the switch-over device comprises a Hall effect switch.

1 6. A camera substantially as hereinbefore described with reference to Figs. 1 and 2 or Figs. 1 and 3 of the accompanying drawings.