MOTORIZED MOUNT FOR VIDEO PROJECTOR

Description

Technical Field

[0001] The present invention relates to the field of image projection and more particularly concerns a motorized lyre for video projectors with light-emitting diodes or lasers. Prior art

[0002] Previously, cinema or video projectors were traditionally made up of an incandescent lamp or a discharge lamp such as Xenon or metal halide HMI (Hydrargyre medium-arc iodite), and a reflector to direct the light beam from this lamp towards an optical system comprising one or more lenses arranged in the light beam. In stage or show projectors, different shutters were also placed at the output of the optical system to ensure the creation of special effects, for example a cutting knife, a color wheel, an iris and a gobo wheel.

[0003] However, in recent years, medium or high-power projectors have appeared on the image projection market, particularly video, whose light sources, intended to replace these discharge or incandescent lamps, are made up of LEDs or laser diodes. Unfortunately, these video projectors are heavy (around 50 to 200 kg), bulky (around a cubic meter) and very noisy. These are monobloc projectors, the light source being associated with the video engine (or video head), of the LCD (liquid crystal), LCOS (liquid crystal on silicon) or DLP (digital light processor) type for example, whose control is also relatively complex. The motorized lyre receiving the video projector must therefore be able to accept such weight and volume, which results in an unwieldy assembly and a source of enormous constraints (fixing, stabilization, repositioning precision, repeatability of movement, absence of vibration, etc.).) likely to considerably limit the use that can be made of such a video projector. A motorized lyre with a video projector is disclosed by document US 2014 / 139426. Statement of the invention

[0004] The present invention proposes to overcome these constraints with a video projector that is lighter, less bulky, less noisy and whose maneuverability, that is to say the amplitude, precision of movements and speed of movement, is greatly increased. An aim of the invention is also to reduce the current complexity of controlling the servo-control of this video projector.

[0005] These aims are achieved by a motorized lyre intended to receive a video projector in a support and having a base, a first arm and a second arm, characterized in that the first arm is connected to the base at a first motorized rotation axis, the second arm being connected to the first arm at a second motorized rotation axis and the second arm is connected to the support at a third motorized rotation axis, the motorized rotation axes each consisting of a motor coupled to a geared motor assembly in direct contact with the arm or the support to be controlled and each of the motors of the motorized lyre comprises its own control card equipped with a microprocessor or microcontroller locally managing the rotational position data of the associated motor received on the common data line according to its own preprogrammed control law, each control card having a code wheel making it possible to identify a specific motor.

[0006] Thus, the direct axis motorization allows excellent precision whatever the direction of rotation of the motor and the integration of a third axis of rotation compared to conventional two-axis motorized lyres allows the management of an additional adjustment parameter which does not exist on prior art solutions and relates to the positioning of the image in “portrait” or “landscape” mode.

[0007] Preferably, the motors are stepper or brushless DC motors and the direct drive geared motor assemblies are elliptical reducer types with very low hysteresis, typically less than 0.5 Arcmin. Depending on the embodiment envisaged, the first and second arms have an “L” or “U” shape. In this second case, the first and second arms are further connected by a simple axis free to rotate and coaxial with the second motorized rotation axis.

[0008] Preferably, the support comprises an electrical connector intended to be connected to the video projector to ensure the power supply and the control of motors of the video projector from the control unit according to a daisy chain. Advantageously, the base comprises an AC / DC converter, a battery and a control unit delivering on a power line the energy necessary to supply power to the different motors of the lyre and the video projector and on a common data line the position data necessary to control the rotation of the different motors of the lyre and the video projector.

[0009] Advantageously, each of the control cards is configured to maintain from the battery and in all circumstances a minimum supply voltage necessary to save the position of each of the lyre motors in standby mode as well as when powered down.

[0010] The invention also relates to an assembly comprising a video projector and a motorized lyre as mentioned above. Brief description of the drawings

[0011] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate an exemplary embodiment thereof without any limiting character and in which: [ Fig. 1 ] there figure 1 is a perspective view of a first example of a motorized video projector support lyre according to the invention, [ Fig. 2 ] there figure 2 is a perspective view of a second example of a motorized video projector support lyre according to the invention, [ Fig. 3 ] there figure 3 is an exploded view of the motorization of each axis of rotation of the motorized lyre of the figures 1 ou 2 , [ Fig. 4 ] there figure 4 shows the electrical circuit controlling the different positions of the motorized lyre of the figures 1 ou 2 , [ Fig. 5 ] there figure 5 illustrates in a first position the movement of the motorized lyre of the figure 1 along a first axis of rotation, [ Fig. 6 ] there figure 6 illustrates in a second position opposite to the first the movement of the motorized lyre of the figure 1 along the first axis of rotation, [ Fig. 7 ] there figure 7 illustrates in a first position the movement of the motorized lyre of the figure 1 along a second axis of rotation, [ Fig. 8 ] there figure 8 illustrates in a second position opposite to the first the movement of the motorized lyre of the figure 1 along the second axis of rotation, [ Fig. 9 ] there figure 9 illustrates in a first position the movement of the motorized lyre of the figure 1 along a third axis of rotation, and [ Fig. 10 ] there figure 10 illustrates in a second position the movement of the motorized lyre of the figure 1 along the third axis of rotation. Description of the embodiments

[0012] There figure 1 illustrates a motorized lyre 10 according to the invention supporting a video projector 12. By video projector, we mean a complete projector when it is small or low power or else only the video head, the light source being remote, when it is high power, typically greater than 10,000 lumens. This lyre / projector assembly is advantageously fixed by collars or clamps 14 secured to the base 100 of the motorized lyre to one or more rails 18 themselves fixed for example to the ceiling of a stage such as a performance hall. But of course any other suitable fixing means is possible, this assembly can simply rest by its base 100 on a flat surface.

[0013] According to the invention and in a first exemplary embodiment, this motorized lyre intended to receive the video projector 12 in a support frame 102 comprises two arms 104, 106 in the shape of an “L” each having a first and a second end, the first end 104A of the first arm 104 being connected to the base 100 at a first vertical axis of rotation 108 and the second end 104B of the first arm 104 being connected to the first end 106A of the second arm 106 at a second horizontal axis of rotation 110 perpendicular to the first vertical axis of rotation 108, the second end 106B of the second arm 106 being connected to the support frame 100 at a third vertical axis of rotation 112 perpendicular to the second horizontal axis of rotation 110 and coaxial (in its rest position) with the first vertical axis of rotation 108.Each rotation axis 108, 110, 112 is motorized by a motor-reducer assembly 114, 116; 118, 120; 122, 124 in direct drive with this rotation axis (also called direct axis motorization), that is to say without pulley or belt generating vibrations (of jerks during accelerations or decelerations) and significant hysteresis (or backlash). The motors are typically stepper type motors or for example brushless direct current and the reducers are very high precision motor-reduction assemblies of the elliptical reducer type from the company Harmonic Drive ®< for example whose hysteresis is less than 0.5 Arcmin (i.e. 0.0083°). In addition, it is also possible to manage via the motorized lyre the motors (and their associated geared motor assemblies) for tilt 126, zoom 128 and focus 130 of the video projector (each illustrated in the . figure 3 ), as will be shown below with the description of the electrical circuit of the motorized lyre.

[0014] There figure 2 illustrates a second example of embodiment which differs from the first in that the support frame is limited to a simple support plate 132 on which the video projector 12 is fixedly held and in that the two arms 134, 136 of the motorized lyre now have a symmetrical “U” configuration.The first arm 134 is connected to the base 100 at the first motorized rotation axis 108 which passes through its center and the second arm 136 is connected to the support plate 132 at the third motorized rotation axis 112 which passes through its center and which in its rest position is coaxial with the first rotation axis 108, the second arm 136 being connected to the two ends 134A, 134B of the first arm 134 by its own two ends 136A, 136B, the second motorized rotation axis 110 passing as previously through two of these ends 134A, 136A, the other two ends 134B, 136B, coaxial and opposite, being connected by a simple free rotation axis, that is to say non-motorized 138.

[0015] The previous support structure whether it is simple ( figure 1 ) or double ( figure 2 ) arm achieves a perfect balance of masses with a center of gravity that allows it to support high weights (from 20 to more than 100 kg) without significant lever arms and thus ensures perfect mechanical control without vibrations and with placement precision for distances from the stage of 10 to 100 m, exceptional quality of movement and repeatability. This balanced structure allows the motorized lyre to be used in any position, placed on the ground or suspended or even held laterally offset.

[0016] The integration of at least one additional axis compared to conventional two-axis motorized lyres allows the management of an additional adjustment parameter that does not exist in prior art solutions. Indeed, the image of a video projector has a ratio of 16 / 9 or even 4 / 3 and it is therefore appropriate to be able to position the image in “portrait” mode as well as in “landscape” mode, which is made possible with the presence of the third motorized rotation axis 112.

[0017] There figure 3 shows in more detail and in the form of an exploded view the motorization of each rotation axis 108, 110, 112 from each motor 114, 118, 122 on the axis of which is mounted in the rear part an electromagnetic brake 114A, 118A, 122A and in the front part an electric collector 114B, 118B, 122B housing the motor and ensuring the passage of the power and data described above, from the static part to the mobile part, and up to the support 102 or the arms 104, 106; 134, 136 driven by the motor-reduction assembly 116, 120, 124.

[0018] The electrical circuit providing the motorization of the lyre is illustrated in figure 4 . The lyre receives in its base 100 from a remote control panel 200, for example in a control room, an alternating voltage supply 100A and control data 100B necessary for moving the lyre on its different axes. This alternating supply voltage, typically 110 / 240 Volts 50 / 60Hz, is transformed in an alternating / direct converter 1000 into one or more direct voltages typically between 12 and 48 Volts ensuring the charging of a battery 1002 itself delivering, depending on the voltage received, a direct voltage also between 12 and 48 volts for the power supply of a control unit 1004 which may include a memory and also directly receiving the control data 100B from the control panel 200.

[0019] The control unit 1004 delivers on a power line 100C the energy necessary to power the various motors of the lyre and the projector and on a common data line 100D, according to communication protocols known as RS485, DMX512 or Art-Net, the position data necessary to control the rotation of the various motors of the lyre and the projector.Unlike the lyres of the prior art where a single control card is connected in a star to all the controlled motors, each of the motors of the invention comprises its own control card 1140, 1180, 1220, 1260, 1280, 1300 equipped with a microprocessor (typically a microcontroller from the AVR ®< family from Microchip Technology) locally managing the rotational position of the associated motor according to a preprogrammed control law with a displacement speed, an amplitude of movement, an acceleration / deceleration curve and a predefined torque specific to each controlled motor.The connection between the lyre and the projector is made at the level of a connector 140 allowing the power supply and the controls of its own motors to be relayed to the projector and a daisy chain to be maintained between all the motors controlled by the control unit 1004 in which each autonomous control card receives from the “upstream” card to which it is connected, the power and data lines, which it retransmits to the “downstream” card to which it is also connected, each motor control card having a code wheel allowing a specific motor to be identified.

[0020] The control cards are configured to maintain in all circumstances a minimum supply voltage necessary to save the position of each of the motors of the lyre in standby mode as well as in off mode, with a high permanent holding torque facilitated by the presence of the electromagnetic brake on each of the rear axles output from the motors 114, 118, 122. Typically, this information is saved in the microsecond following the switching off of the lyre (including in the event of micro-cuts) in the internal memories of the microprocessors of these cards (typically a static RAM, a Flash memory or an electrically programmable read-only memory). This information can also be saved in the memory of the control unit 1004 when it has one.

[0021] The operation of the motorized lyre is now explained with regard to the figures 5 à 10 which show the different movements of this lyre around its motorized rotation axes.

[0022] On the figures 5 et 6 are shown, in two opposite positions, the rotation around the first motorized vertical rotation axis 108. This rotation corresponds to the rotation of the projector on its horizontal axis (the “Pan” axis of the projector). This rotation could be carried out over 360° but, in practice, it is limited to a displacement range of 200° between -100° and +100° to allow the passage of fiber optic cables when the video projector includes light sources remote from the video projection head comprising the lens.

[0023] On the figures 7 et 8 are shown, in two opposite positions, the rotation around the second horizontal motorized rotation axis 110. This rotation corresponds to the rotation of the projector on its vertical axis (the “Tilt” axis of the projector). This rotation could be carried out over 360° but in practice it is limited to a displacement range of 200° between -100° and +100° to allow the passage of fiber optic cables when the video projector includes light sources remote from the video projection head comprising the lens.

[0024] On the figures 9 et 10 are shown, in two opposite positions, the rotation around the third vertical motorized rotation axis 112. This rotation corresponds to the rotation of the projector on itself (the “Pan-roll” axis of the projector). This rotation could be carried out over 360° but in practice it is limited to a movement range of 100° between -50° and +50° sufficient to allow the positioning of the video projector in “landscape” mode ( figure 9 ) or in “portrait” mode ( figure 10 ).

[0025] With the invention, we obtain a high-performance lyre both technically for the quality of movements during visual movements and economically to ensure, if necessary, the positioning of inaccessible projectors.

[0026] Of course, if in the illustrated example, reference was essentially made to a video projector, it is quite obvious that such a motorized lyre can be implemented with a projector of still or animated images.

Claims

1. Motorised bracket intended to receive, in a support (102, 132), a video projector and having a base (100), a first arm (104, 134) and a second arm (106, 136), in which the first arm is connected to the base (100) at a first motorised rotation axis (108), the second arm being connected to the first arm at a second motorised rotation axis (110) and the second arm is connected to the support (102, 132) at a third motorised rotation axis (112), characterised in that the motorised rotation axes each consist of a motor coupled to a geared motor assembly in direct engagement with the arm or the support that is to be controlled and in that each of the motors of the motorised bracket comprises its own control card (1140, 1180, 1220) equipped with a microprocessor or microcontroller locally managing the rotation position data of the associated motor received on the common data line according to its own preprogramed servo-control law, each control card having a code wheel allowing a specific motor to be identified.

2. Motorised bracket according to claim 1, characterised in that the motors are stepper motors or brushless DC motors and the geared motor assemblies in direct engagement are elliptical reduction gears with very low hysteresis, typically less than 0.5 Arcmin.

3. Motorised bracket according to claim 1 or claim 2, characterised in that the first and second arms (106, 106; 134, 136) have an "L" shape or a "U" shape.

4. Motorised bracket according to claim 3 and in which the first and second arms (134, 136) have a "U" shape, characterised in that the first and second arms are, in addition, connected via a single free rotation axis (138) that is coaxial with the second motorised rotation axis 110.

5. Motorised bracket according to any one of claims 1 to 4, characterised in that the support comprises an electrical connector (140) intended to be connected to the video projector in order to ensure the supply of power and the control of motors (126, 128, 130) of the video projector from the control unit (1004) according to a daisy chain.

6. Motorised bracket according to claim 5, characterised in that the base comprises an AC / DC converter (1000), a battery (1002) and a control unit (1004) delivering, on a power line (100C), the energy necessary for the power supply of the various motors of the bracket and of the video projector and, on a common data line (100D), position data required in order to control the rotation of the various motors of the bracket and of the video projector.

7. Motorised bracket according to claim 1, characterised in that each of the control cards is configured to maintain from the battery (1002) and in all circumstances, a minimum supply voltage necessary for saving the position of each of the motors of the bracket, in standby mode and when switched off.

8. Motorised bracket according to claim 7, characterised in that the microprocessor or microcontroller has a static RAM memory, flash memory or electrically programmable ROM memory.

9. Assembly comprising a video projector and a motorised bracket according to any one of claims 1 to 8.