DE20002420U1 - TV receiver with a remotely controllable and / or dimmable backlight - Google Patents

Description

Werner Dreykdrn-Lindner ste.nlachstrasse &zgr;

Dipl.-Ing. D-9Q57 1 Schwaig

Patent Attorney

European Patent Attorney Tel: Dgl l- 5Q5B99

European Trademark Attorney fax: 091 1- 5&Ogr;5&Bgr;99

Metz-Werke GmbH & Co KG

Ohmstrasse 55
D-90513Zirndorf

Wednesday, 09 February 2000
MetzG03

Description

"Television receiver with a remotely controlled and/or dimmable backlight"

State of the art

The invention relates primarily to a television receiver with a remote-controlled and/or dimmable background lighting, which can be inserted into a contour-adapted recess in the rear wall and/or the television housing and can be electrically contacted there with a contour-adapted plug strip and which is connected by means of a remote control transmitter and a remote-controlled switch arranged in the power supply line (preamble of claim 1).

Backlights for a television receiver have been known for a long time.

For example, DE 36 29 593 A1 discloses a lighting device for a television set which automatically switches a light source on or off when the television receiver is switched on, by controlling the light source of the lighting device using a switching device containing a switch depending on the brightness of the room. The mains plug of the television set is plugged into the mains socket of the electronic switching device, which in turn is plugged into another mains socket, and a flexible electrical cable leads from the electronic switching device to the light source. In this way, in conjunction with a switched-on television set and when the brightness of the room decreases, a light source that is gentle on the eyes of the television viewer is automatically switched on.

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For this purpose, the switching device contains a detector that detects a current flow when the device is switched on and emits a control signal. This control signal is preferably linked via an AND gate to a second control signal that is derived from an optoelectronic element. This ensures that the light source is only switched on when the device is switched on and the room brightness is correspondingly low. If the device is switched off, the light source is simultaneously switched off via the switch. Depending on the design of the optoelectronic element, the output signal of this element can be fed directly to the AND gate or indirectly via a NOT gate to the AND gate.

The mechanical structure is selected in such a way that a body that can be rotated 360° around its central axis is arranged on the side of the light source and that carries the optoelectronic element on one of its outer surfaces. This measure makes it possible to rotate the body together with the optoelectronic element on it so that the optical axis of the optoelectronic element points in a desired direction. This provides a very simple way of adapting the incidence of light on the optoelectronic element to different room or lighting conditions. Alternatively, the lighting device can also be designed in such a way that the brightness of the light source is controlled depending on the respective room brightness using a controllable brightness controller.

In a further development of this, a device for dimmable background lighting using a modified remote control is known from DE 38 37 338 A1. In particular, it is provided that the television or video device has a socket for the plug of a lamp parallel to the input for the mains voltage. Furthermore, a transmitter module has at least one additional button for switching the lamp on and off and/or two additional buttons for controlling the brightness of the lamp. Finally, at least one additional output for an electronic component that influences the current path of the lamp is provided in the receiver module for controlling the lamp. Alternatively, the electronic component has a transistor that opens and closes the current path and a dimmer that controls the brightness of the lamp.

These measures ensure that viewers - with television or video devices in standby mode - can switch the lamp on and off remotely by switching on the programs using the remote control. Preferably, in standby mode, the lamp is automatically switched on at the lowest brightness level or, after a program has ended and been switched off, is automatically switched to the lowest brightness level until the next program is switched on.

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It is also possible to pick up an electrical signal representing the brightness of the television images from the television or video tube and compare it with an electrical signal representing the light intensity of the lamp. If the deviation from a preset threshold is too great, the brightness or light intensity of the lamp is automatically regulated accordingly. The main advantage of this is that it prevents eyestrain. In this further development, the lamp is also plugged into the mains socket, which is now located on the television housing, via a flexible electrical cable.

The same applies to television sets with dimmable ambient lighting in accordance with G 93 20 603.8. Since the voltage at the power socket can be switched, the use of the ambient lighting of the television is not limited to when the television is switched on and in use. The lighting device can therefore also be used when the television is switched off but connected to the mains and can therefore serve as normal room lighting. For safety or optical reasons, the power socket mentioned can also be covered when not in use. This can be achieved structurally using flaps, sliders or similar. In addition, a switch can be activated when the cover is opened, which first connects the power socket to the voltage of the dimmer output. Independently of the dimmer and the power socket mentioned, it is also proposed to install a relay with switching contacts in the television that can be switched by the remote control.

Finally, from G 92 18 378.6, a television receiver is known in which the lighting unit is integrated into the television housing. The housing is designed as an essentially funnel-shaped housing with a conical part at the rear. In the top side, in the rear edge area, a recess is provided which is covered by an angled cover and which can be removed if necessary. For this purpose, connecting elements to the rear wall are provided, e.g. hooks which releasably engage in recesses. The recess can have continuous boundary walls or just abutments onto which the lighting unit can be placed if the cover is removed.

The lighting unit consists of a reflector housing in which the lighting fixture, for example a neon lamp, is inserted. For this purpose, the sockets for the neon lamp must be provided on the sides of the reflector housing. If it is an energy-saving lamp, a corresponding socket must be provided on one side. The lighting fixture is supplied with power via the supply line, which is connected to the power supply part of the device. The power supply part is located in the housing and is in turn connected via a

Mains connection cable, which is led out through an entry opening in the housing, can be connected to the house power supply network.

The power supply line also contains a remote-controlled switch, which consists of an electronic control unit and a relay with relay contact. This switch can be controlled by the device's television control receiver circuit. The control itself is carried out via the remote control transmitter by pressing the buttons provided there. One button can be used as an on button and as a dimmer button at the same time, for example in an increasing control direction, so that the power consumption of the lighting fixture and thus the light intensity can be regulated at the same time via a control circuit - which can be integrated in the control circuit, for example. The other button is used to operate the dimmer in the opposite direction, so that the light intensity of the lighting fixture can be reduced if necessary.

The supply line can be a fixed wiring inside the device that leads into a socket inside the recess. For the purpose of electrical contact, a plug strip is attached to the outside of the reflector housing on the side facing the device, which connects with measuring contacts to the fork contacts of the socket. This makes it easier, for example, to retrofit a prepared television with a corresponding lighting unit.

As the above assessment of the state of the art shows, background lighting for television receivers has been known for a long time. However, it has not been considered how - from a safety perspective - protection against accidental contact with mains voltage and high-voltage contacts can be implemented when removing the back panel or cover and/or how the light can be changed in a simple and safe manner. For this reason, television receivers equipped in this way have not proven themselves in practice and have not been able to gain acceptance due to a failure to meet safety requirements. This is particularly important because the entertainment electronics industry is an extremely progressive, development-oriented industry that is very quick to adopt and implement improvements and simplifications.

problem

Compared to the known background lighting for a television receiver, the object of the invention is to design it in such a way that safety requirements are met.

invention

These problems are solved, starting from a television receiver with a remote-controlled and/or dimmable background lighting according to the preamble of claim 1, in that, for contact protection, an encapsulation of the background lighting is provided by a translucent lamp cover and a lamp holder which encompasses this at least in sections in edge areas and that, in order to open the encapsulation, fastening means for the background lighting fastened to the outside of the rear wall are only accessible from the inside of the rear wall after loosening and removing the rear wall.

Advantageous effects of the invention

The television receiver according to the invention with a remote-controlled and/or dimmable background lighting has the advantage that by releasing and removing the back panel and only then opening the casing, an accident caused by electric shock can be reliably avoided in a surprisingly simple manner. It is generally known that a television receiver must be disconnected from the mains before the back panel is removed. This is regularly expressly indicated by a warning (pull out the mains plug before removing the back panel). The television receiver according to the invention therefore also meets high safety requirements, for example those for certification with the VDE or CE test mark. Another advantage is that the casing creates a dust- and water-tight design for the background lighting.

Further embodiments of the invention

In a preferred embodiment of the invention according to protection claim 2, a gas discharge lamp that can be dimmed by means of a control circuit is provided as the luminaire and a voltage monitor is provided as protection in the event of contact and/or to protect the control circuit from high voltages when the lamp is not fitted or has poor contact.

This embodiment of the invention has the advantage that both the user and the control circuit are protected from high voltages when the lamp is not fitted or has poor contact, since gas discharge lamps require a high ignition voltage, for example of approximately 1,500 V, when starting up.

According to protection claim 3, the lamp holder is in the form of an L-angle and the lamp cover is U-shaped and after assembly the lamp cover encloses one leg of the L-angle in the edge area and abuts the other leg of the L-angle.

This two-part encapsulation is both easy to manufacture and easy to install. Due to its special design, the light cover rests on the light holder during installation, so that it does not have to be held or positioned.

In a further development of the invention, according to claim 4, the lamp cover has legs of different lengths and which are convex in the direction of extension and the lamp holder is also designed to be convex.

This development of the invention has the advantage that the essentially elongated lamp cover is dimensionally stable and the lamp holders can also reliably support a heavy background lighting.

Preferably, according to claim 5, a guide for the fastening means is provided on the inside of the rear wall and the fastening means fix the luminaire cover to the outside of the rear wall.
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This guide enables quick installation, especially in confined spaces.

In a further development of the invention, according to claim 6, at least two screws are provided as fastening means for mounting the background lighting, which screws penetrate the guide designed as a guide sleeve and an opening in the lamp holder and engage in a screw bushing of the lamp cover.

This development of the invention has the advantage that a reinforced support of high stability is created in a simple manner in the area of the positive and non-positive connection between the background lighting and the rear wall.

Preferably, according to protection claim 7, the lamp holder has a reflector surface on the side facing the lamp cover or carries a reflector.

This design creates improved light output even at low illuminance levels.

According to claim 8, the screw has a thread-free section with a smaller diameter than the screw thread.

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The advantage is that pre-assembly can already be carried out and that the pre-assembled screw cannot be lost.

Preferably, according to claim 9, the lamp holder carries at least two opposing lamp holding parts.

With this design, it is possible to accommodate lamp bodies of different sizes by moving the lamp holders.
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In a further development of the invention, according to claim 10, the lamp holder and the lamp cover have additional spring locking connections or bayonet locks.

This development of the invention has the advantage that the assembly effort is reduced. In addition, a vibration-proof and permanent connection between the background lighting and the rear panel of the television receiver is ensured, even if it is frequently removed, e.g. to change the gas discharge lamp.

According to claim 11, when the back panel is removed, the electrical power supply for the backlight is disconnected.

This makes it possible to further improve the contact protection of the television receiver according to the invention.

In a further development of the invention, according to claim 12, it is provided that the background lighting can be fixed to the outside of the rear wall by fastening means that can be covered or require handling.

The advantage is that the multiple manual steps and use of special tools, namely removing the cover from the fastening device, for example a cap from a screw with a Torx head, offer additional security against unprofessional loosening.

Description of the invention

Further advantages and details can be found in the following description of a preferred embodiment of the invention with reference to the drawing. In the drawing:

FIG. 1 a plan view of the rear wall outside,
FIG. 2 a plan view of the inside of the rear wall,

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FIG. 3 is a section through the television receiver according to the invention in the plane of the line A-A of FIG. 1 and

FIG. 4 shows the circuit diagram of a preferred embodiment of the background lighting according to the invention.

FIG. 1 shows a remote-controlled and/or dimmable background lighting for the television receiver application. However, it can be used in almost any electrical device that has to meet high safety requirements. This is due to the fact that the combination according to the invention, namely encapsulation and opening of the encapsulation only after loosening parts of the housing of the electrical device, allows easy adaptation to the respective circumstances without changing the invention.

As already mentioned, the television receiver according to the invention has an encapsulation of the background lighting L by means of a translucent lamp cover LA and a lamp holder LH which surrounds this at least in sections in edge areas for protection against contact. To open the encapsulation, fastening means S for the background lighting L fastened to the outside of the rear wall R are only accessible from the inside of the rear wall R after loosening and removing the rear wall R.

In detail, it is provided that the lamp holder LH is designed in the form of an L-angle and the lamp cover LA is U-shaped and that after assembly the L-angle encloses one leg Sl of the lamp cover LA in the edge area and butts against the other leg S2. The lamp cover LA preferably has legs Sl, S2 of different lengths and convex in the direction of extension, with the lamp holder LH also being designed convex.

On the inside of the rear wall RI, a guide FH is provided for the fastening means S, which fix the light cover LA to the outside of the rear wall. To mount the background lighting L, at least two screws S are preferably provided as fastening means, which pass through the guide designed as a guide sleeve FH and an opening D in the light holder LH and engage in a screw bushing SB of the light cover LA. The screw S can advantageously have a thread-free section with a smaller diameter than the screw thread.

In detail, the lamp holder LH can have a reflector surface on the side facing the lamp cover LA or can carry a reflector.

Furthermore, at least two opposing lamp holder parts LH1, LH2 can be attached to the lamp holder LH. Preferably, the lamp holder LH and the lamp cover LA have additional spring-loaded connections or bayonet locks.
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Finally, by removing the rear panel R, the electrical power supply for the backlight L can be disconnected.

Alternatively, the background lighting L can be fixed to the outside of the rear wall using fastening devices that can be concealed or require handling.

The light is a gas discharge lamp that can be dimmed using a control circuit, with voltage monitoring being provided as protection against contact and/or to protect the control circuit from high voltages when the lamp is not fitted or has poor contact. The circuit diagram of a preferred embodiment of the background lighting L according to the invention is shown in FIG. 4 and its function is described below with reference to the associated circuit parts.

The present circuit supplies the necessary ignition voltage and the lamp current required for operation of a gas discharge lamp.

The radio interference suppression function is essentially implemented using the capacitors C12, C13, C14 and C16. The X-capacitors C12, C13, C14, C16 and the two inductors L2 and L4 serve to reduce the conducted interference to the prescribed values.

Rectification and filtering is carried out using D7 and CIl. When operating with alternating voltage, the bridge rectifier D7 converts this into a direct voltage. The capacitor CIl smooths the rectified voltage.

The gas discharge lamp is initially supplied with the lamp voltage generator with C6, Ll, C9, L3, and ClO. The lamp current is freed from the DC component using ClO. The upstream transformer L3 converts the voltage to the high value of the required lamp voltage. A sinusoidal alternating voltage is present on the primary side of L3. This is generated by the resonance circuit consisting of Ll and C9. The capacitor C6 is used to block the DC component.

Furthermore, the chopper circuit with Ql, Q2, ICl, C4, R6 and C5 is provided. In detail, the two transistors Ql and Q2 together form a so-called push-pull stage. The ICl is used for the mutual control

of both transistors. This generates a square wave voltage with a frequency that is variable within certain limits. This signal is provided for the downstream lamp supply. The frequency of the signal is also generated by the IC1. The connection pins RT and CT are connected to C4 and R6 accordingly. A digital signal of this frequency is present at point RT, while an analog charge transfer curve can be seen at pin CT, which oscillates between 1/3 and 2/3 of the supply voltage. In order to provide the transistor Q1 with a sufficiently high control signal, a boosted voltage is generated from the output signal by the IC's internal charge pump using C5, which is buffered in the IC1.

The IC supply itself is implemented using R4, R5, R21, C7, R3, D5, D6, Cl5 and R14. The voltage supply for ICl is buffered with C7. To start the circuit, the charging current for C7 and thus the supply voltage is supplied from the 230V supply voltage via the resistors R4, R5 and R21. However, this current is only sufficient for a short start-up and the electrolytic capacitor voltage at C7 also drops again. After a short time, however, the supply from the switching signal starts, which provides sufficient current for continuous operation. Current is supplied to the Zener diode D6 via Rl4 and Cl5, so that a low direct voltage is present here. The buffer capacitor C7 is thus recharged via D5 and R3 with each switching pulse.

To ignite the gas discharge lamp, a series circuit is provided, consisting of the capacitor C9 and the series choke Ll, which form a series resonance circuit. Its quality is sufficient to generate the necessary voltage to ignite the gas discharge lamp.

In a further embodiment of the invention, an idle shutdown is provided with Rl 5, R16, Rl 7, D9, C8, Rl 3, Q4 and Q5. A voltage monitor has been installed to protect the circuit from unnecessarily high voltages when the lamp is not fitted or has poor contact. The presence of a voltage that is too high is detected by the resistors Rl 5, Rl6 and Rl7. This signal is rectified via D9 and fed to the two transistors Q4 and Q5 connected to the thyristor. In the event of a fault, these switch off the supply voltage of ICl.

The lamp current is controlled by means of R9, D2, RIO, R28, C3, Q3, R7, D3 and D4. The lamp current is measured by the measuring shunt R9 and fed to the transistor Q3 via RIO and R28 and C3. This has a frequency-influencing effect on the timer of ICl via R7 and the two diodes D3 and D4.

The supply voltage for the dimming with C18, R24, D8, DIl and Cl7 is generated by sending a current pulse from the switching signal at each cycle via Cl8 and R24 via the Zener diode D8. The Zener voltage supplies a charging pulse for the electrolytic capacitor C17 via DIl.
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The influence of dimming on the lamp current is determined by X2, Rl 8, IC2, R26, C19, R19, D12 and R25. A PWM signal with a period of 64 ^s is applied to the X2 connector. The on-time varies from 0 μβ to 48 ^s. The resistor Rl 8 and the optocoupler IC2 provide a safety separation point with appropriate clearances. The pulses are smoothed to a direct voltage using R26, R19 and C19. An additional base current is sent through Q3 via the diode Dl2 and the resistor R25 and the control is influenced in such a way that the lamp current is reduced.

Finally, to slow down the ignition process, the voltage rise at Cl7 during switch-on was used to slowly ramp up the power.

The remote control system according to the invention has the advantage that the risk of an accident due to electric shock in a television receiver with a remotely controllable and/or dimmable backlight L can be avoided in a surprisingly simple manner.

All of the possible designs shown and described, as well as all of the new individual features disclosed in the description and/or the drawing and their combination with one another, are essential to the invention. For example, if the encapsulation is attached from the outside of the rear wall, the power supply can be disconnected when the encapsulation is opened; the light holder can be U-shaped and the light cover can be designed as a cover plate, etc.

Claims (12)

1. Television receiver with a remote-controlled and/or dimmable background lighting (L) which can be inserted into a contour-adapted recess in the rear wall (R) and/or the television housing and can be electrically contacted there with a contour-adapted plug strip and which is connected by means of a remote control transmitter and a remote-controlled switch arranged in the power supply line, characterized in that an encapsulation of the background lighting (L) by a translucent lamp cover (LA) and a lamp holder (LH) which encompasses this at least in sections in edge areas is provided for contact protection and that in order to open the encapsulation, fastening means (S) for the background lighting (L) fastened to the outside of the rear wall (R) are only accessible from the inside of the rear wall (R) after loosening and removing the rear wall (R). 2. Television receiver according to claim 1, characterized in that a gas discharge lamp dimmable by means of a control circuit is provided as the light and that a voltage monitor is provided as contact protection and/or to protect the control circuit from high voltages when the lamp is not fitted or has poor contact. 3. Television receiver according to claim 1 or 2, characterized in that the lamp holder (LH) is in the form of an L-angle and the lamp cover (LA) is U-shaped and that after assembly the L-angle encloses one leg (S1) in the edge region and butts against the other leg (S2). 4. Television receiver according to claim 3, characterized in that the lamp cover (LA) has legs (S1, S2) of different lengths and which are convex in the direction of extension and that the lamp holder (LH) is also convex. 5. Television receiver according to claim 1, characterized in that a guide (FH) for the fastening means (S) is provided on the inner side (RI) of the rear wall and that the fastening means (S) fix the lamp cover (LA) to the outer side of the rear wall. 6. Television receiver according to claim 1 or 5, characterized in that for mounting the background lighting (L) at least two screws (S) are provided as fastening means, which penetrate the guide designed as a guide sleeve (FH) and an opening (D) in the lamp holder (LH) and engage in a screw bushing (SB) of the lamp cover (LA). 7. Television receiver according to claim 1, characterized in that the lamp holder (LH) has a reflector surface or carries a reflector on the side facing the lamp cover (LA). 8. Television receiver according to claim 6, characterized in that the screw (S) has a thread-free section with a smaller diameter than the screw thread. 9. Television receiver according to one or more of claims 1 to 8, characterized in that the lamp holder (LH) carries at least two lamp holding parts (LH1, LH2) lying opposite one another. 10. Television receiver according to one or more of claims 1 to 9, characterized in that the lamp holder (LH) and the lamp cover (LA) have additional spring locking connections or bayonet locks. 11. Television receiver according to one or more of claims 1 to 9, characterized in that when the rear panel (R) is removed, the electrical power supply for the background lighting (L) is disconnected. 12. Television receiver according to claim 1, characterized in that the background lighting (L) can be fixed to the outside of the rear wall by fastening means which can be covered or require a handle.