MXPA98007757A - Integrated liquid crystal screen projector, compa - Google Patents

Abstract

Disclosed is a liquid crystal display (46) projector (LCD projector) having a display unit consisting of a panel (46) of transmitting LCD and Fresnel lenses (48, 50) arranged on both sides thereof, a light source projection unit (30, 34, 36, 38) for illuminating the screen and a projection lens (42) for projecting the light transmitted through the screen onto a projection screen. The panel (LCD) of the screen is arranged to articulate, rotate, between a storage position, in which the panel is parallel to the light path and an operative position, in which the panel is inclined or perpendicular to the path of light. (A small inclination that allows the correction of wedge distortion). The projector can be accommodated in a substantially rectangular flat housing having hinged covers (flaps) (14, 16, 54, 56) on its upper and lower walls, the covers are arranged to be opened in order to allow the panel to be opened. LCD extends beyond the walls of the housing when it is rotated in its operative position, such that in the storage position, the housing has a reduced size. The articulated or rotating movement of the LCD is coupled to the movement of the projection lens (42), which is retracted into the housing when the LCD is rotated in its storage position.

Description

COMPACT INTEGRATED LIQUID CRYSTAL DISPLAY PROJECTOR BACKGROUND OF THE INVENTION Field of the invention The present invention relates in general to projection systems, in particular with a compact projector (portfolio size or portfolio), wherein the components can to be moved to allow compaction for storage and more particularly with a projector having an electronically addressable screen, such as a liquid crystal display.

Description of the prior art Elevated, slides (or transparencies) and video projectors, as historically configured, occupy a considerable volume of space when they are ready for use. This is not only because the necessary components are large, but due to the limitations of the optical technology, certain amounts of unoccupied space are necessary to accommodate the light cones and the ventilation ducts. It can be considered that this bulky space is a nuisance or at least an inconvenience for the user and as a result a considerable effort has been devoted to provide features that result in a unity REF .: 28226 stored smaller, which is expanded or opened for actual use. Examples of the latter are exemplified by U.S. Patent No. 5,374,969 which claims an overhead (or upper) projector (OHP) having a collapsible base and a collapsible lens arm. Another folding unit for transportation and storage, which has a different folding mechanism, is implemented by the OHP sold by the Minnesota Mining and Manufacturing Company (3M -the recipient of the present invention), under model 2770, where the Folding and unfolding mechanism, as it is complex, is extremely simple to put into operation. U.S. Patent No. 4,588,271 discloses a different projector that will be crushed or folded for storage and still be rigid for actual use. In recent years, liquid crystal display (LDC) panels have been added to the traditional overhead projector, which introduces a new use for an established technology. These panels are electronically addressable, that is, the appearance of the final image is controlled by the electronic signals sent to the panel. The electronic signals can come from a computer or they can consist of standard video signals (NTSC) or other appropriate devices. Initially these panels were designed as an addition to a conventional OHP and were added or separated at will according to the desired mode of use of the OHP unit. As the electronically generated and stored presentations became more appreciated, a new class of presentation device appeared, often referred to as an "integrated projector". Such a unit is capable of taking the inputs of a computer or other source of signals and projecting an image on a screen. The modern integrated projectors are capable of projecting useful images even in high ambient light conditions. Such units have developed a patent literature by themselves, a few examples of which are summarized below. U.S. Patent 4,943,154 shows a projector having three "light valves" (a particular form of an addressable liquid crystal display) and a complicated optical path, designed to allow the output of a white light source to be divided into red components , blue and green, printed or formed in images with the three light valves - one for each color - and then to combine again for its projection through a single lens. Such optical systems are complicated to manufacture, to assemble and maintain and occupy a considerable space, weigh a substantial amount and have potential efficiency problems.

An alternative method of use is to have a single LCD panel, optical path and lens, and to interpose in succession red, green and blue filters. As each filter moves in the optical path, the appropriate color image is formed on the LCD. Such units have been limited by the ability of the LCD to respond quickly to changing input signals. You also need a well-designed filter wheel and associated tooling. For these reasons, this method has found little use, if any. U.S. Patent No. 5,07,323 has a projection system that uses liquid crystal LCD screens in transmission mode (one for each color) and a three-dimensional optical path (which means that the optical axes can be directed in three dimensions in two-dimensional place more normal). This is not a space saving feature, but it can serve to redistribute the use of space to produce a smaller print. It is also possible to use what is known as a Three color LCD This panel has an array of microfilters (red, green and blue) printed on the face of the screen and these filters are appropriately routed through the liquid crystal array mounted to register or match them. This type of LCD, while it is a bit more complicated to manufacture, has the advantage of needing only one optical system. In addition, the filters and control elements can never lose alignment and the weight of the LCD needs to be a little more than the weight of a unit of a single color, to save in weight and space. Additional savings in weight are also obtained in the elimination of prisms, filters, spaces, and their assemblies. U.S. Patent No. 5,321,450 describes a projector that exemplifies these principles. By using the mirrors and an angular LCD, you get a low profile. A lens that has its optical axis arranged vertically is used for the projection and a final mirror (which can be folded) redirects the light along a horizontal path. This mirror is the only component that is moved for storage and space saving is less. The "EzPro 500" projector manufactured by CTX OPTO Inc., incorporates a folded lens unit and mirror to obtain compactness for storage. Devices already in use, where compactness is considered a virtue, include laptops and related devices, as can be exemplified by U.S. Patent 5,483,253. In these types of units, an LCD panel is articulated at its trailing edge, so that it can be folded down to become co-planar with the keyboard for storage and transportation. However, these units are normally reflective during operation, sometimes have backlighting and sometimes have been manufactured in a separable manner, such that the panel can be used on for example an OHP. Recently, the organizers "pal top" have also become available. These devices consist of a small computer, keyboard and LCD panel and are even smaller than the laptops mentioned above. The "palmtop" units are folded for storage and fit into a pocket. Users seem to appreciate the small size of the unit during use and the folding feature for storage. Despite the various methods and configurations in the prior art to reduce the size and increase the efficiency of space, there is still room for improvement, particularly since none of the conventional designs make efficient use of the unoccupied space necessary to accommodate the cones of light in the transmitter and reflector systems. It would therefore be desirable and advantageous to devise an integrated, compact LCD projector which takes advantage of this unused space and which also permits easy and rapid deployment during use.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a compact electronic projector comprising generally a body, a light source located in the body, a projection lens located in the body with a line between the light source and the projection lens. which defines a projection axis, a mounting or screen assembly having means for creating an image, the assembly or screen assembly is located on the body and interposed between the light source and the projection lens and means for rotating the assembly or screen assembly, from a storage position, in which the assembly or screen assembly is generally parallel with the projection axis, to a deployed position, in which the screen assembly is disposed at an oblique angle with respect to the projection axis. The assembly or screen assembly may take the form of a liquid crystal display panel transmitter and the means for moving the assembly or screen assembly may also be designed to cause the projection lens to extend at least partially outwardly. of the body in the deployed position and cause the projection lens to retract into the body in the stored position. In one embodiment, the body has doors that are movable between an open position, wherein the screen assembly is in its unfolded position and a closed position, when the screen assembly is in its stored position and the screen assembly is extends through the doors in the deployed position. A rear leg element can be used to adjust the separation angle of the projection axis. The screen assembly (LCD panel) is arranged to rotate around a horizontal axis, in the center of the assembly or assembly. Then, the assembly can be rotated to fill the gaps necessary for the expansion and contraction of the optical beams when the projector is in use. These holes have no useful function when the projector is not in use and are thus available for the storage of the components. Such a feature allows the saving of a substantial volume of space, which makes the closed unit compact and easily transportable. In addition, the simplicity of the optical components also produces a light-weight projector, which further improves portability. Due to the reduction in size, weight and number of components, a unit can be produced at relatively low cost without sacrifice in performance. This invention provides a projector that can be electronically addressed and that is capable of providing excellent image quality and brilliance and that can also be folded and reconfigured for storage and transportation, such that the latter form is compact and easy to transport. For storage, the main benefits conferred by this reconfiguration are the reduction of the total volume of the unit and the absence of protruding parts that could be damaged in another way. It has been found that, for transportation, it is convenient to have a unit dimension as small as possible (ie, a low profile). This allows a handle or carrying handle to attach to the unit and be easily transportable when using only one hand. Projectors that have more equilateral shapes (for example, cubic) need two hands for transportation or when transported in one hand interfere with an easy advance. Furthermore, if the unit is designed in such a way that it has a relatively uniform profile * or exterior, it will suffer less damage if accidentally contacted by other objects and is less likely to interfere with the movement of the person transporting it. . Thus, the most convenient form for transportation is that of a briefcase, portfolio or portfolio or the like.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood by reference to the accompanying drawings, wherein: Figure 1 is a perspective view of an embodiment of the compact integrated LCD projector of the present invention, shown in the storage / transportation state;; Figure 2A is a sectional view of the projector of Figure 1, also shown in the storage / transportation state; Figure 2B is a sectional view similar to Figure 2A, but showing the projector in the deployed state; and Figure 3 is a top plan view of the projector with the upper surface thereof separated, also shown in the unfolded state.

Description of the preferred embodiment With reference now to the figures and in particular with reference to Figure 1, a mode 10 of the compact electronic projector of the present invention is shown. The exterior features of the projector 10 include a box or body 12, two upper retractable doors 14 and 16, a drive button 18, a rear leg adjustment knob 20, a receptacle 24 for a power cable, power (on / off) 26 and one or more ports that provide various types of electrical connectivity (such as video and data controllers), each indicated as 28. In this embodiment, body 12 is similar to a box and its upper surface (which includes the doors 14 and 16) is flat and generally parallel with its lower flat surface (in the storage position) This shape provides a particularly low profile, but those skilled in the art will appreciate that others profiles can be provided which are not rectangular like the projector 10. The body 12 can be constructed of any durable material, but preferably of a lightweight polymer , such as acrylonitrile butadiene styrene (ABS) or polycarbonate. Figures 2A and 2B are longitudinal cross-sectional views of the projector 10 illustrating its storage / transportation status and its deployed state, respectively and it is shown that the projector 10 additionally consists of a light source 30 with a nearby heat sink 32, a collimator (parabolic reflector) 34 and a condenser lens 36 disposed in an opposite manner around the light source 30, an infrared filter (hot mirror) 38 proximate the lens 36 of the condenser, a screen assembly 40 and a lens 42 of projection. All of these components are located in the body 12, although, as seen in Figure 2B, the screen assembly 40 and the projection lens 42 protrude from the body 12 when the projector 10 is deployed. The screen assembly 40 is rotatably or hingedly joined to the interior of the body 12 such that, in the deployed state, the screen assembly 40 is generally perpendicular to the light path, but in the stored state it is general parallel to this light path and occupies the state that is reserved for the cone of light during the operation. With reference to the cross-sectional views of Figures 2A and 2B, the term "longitudinal" is used to describe a direction of the projector that coincides with the projection axis, that is, the generally straight line between the light source. and the projection lens 42. This term is appropriate for the particular mode shown, but should not be interpreted in a limiting sense. Other embodiments may employ folded optical paths, such as through the use of mirrors, catadioptric Fresnel lenses, etc., and (as long as these components could be added to the cost of the device and be less desirable for other reasons), such a device could still benefit from the present invention. Specifically, a lower profile is imparted since the screen assembly is moved to a storage position in which the assembly is generally parallel with the effective direction of the light beam in the region of the screen assembly. As well, while it is certainly preferable that the light reaches the LCD panel at a normal overall angle during use, this is not a critical requirement, since substantial space savings can be obtained without full 90 ° rotation of the assembly or panel assembly, that is, with the light that reaches the panel at an oblique angle, but not orthogonal. A "wedge" correction option (to modify the shape of the image) can still be obtained by selecting the rotation angle of the display panel. A bolt or retaining block (not shown) formed on the interior of the body 12 prevents the screen assembly 40 from turning too much. The light source 30 is preferably a high intensity source such as an EVD lamp (halogen) or a series of high power metal halide lamps (eg, 250 Watts, 400 Watts, 575 Watts), available from Osram (part of Sylvania Co., of Germany) or Philips Electronics of the Netherlands. It is connected to a DC power supply 44 (direct current) of 12 volts, located on the body 12 (see Figure 3). In the embodiment shown, the heat sink 32 consists of two edged strips approximately 25.4 cm (10") long, constructed of an aluminum extrusion 5052. The condenser lens is preferably planar-convex and is constructed of a glass of borosilicate such as Pyrex (a trademark of Corning, Inc.) The IR 38 infrared filter is a conventional hot mirror, such as those available from Bausch &; Lomb. The screen assembly or assembly 40 can take various forms, such as an LCD transmitter panel, a light valve or a micromirror arrangement. In the mode of the projector 10, the screen assembly 40 includes an LCD panel 46, such as the 16.3 cm (6.4") panel, available from Sharp of Japan or Liesegang of Germany and two Fresnel lenses 48 and 50, secured in a housing 52. A fan 55 (see Figure 3) is mounted to the interior of the housing 52 to cool the panel 46. The entire screen assembly is arranged to rotate about a horizontal axis, in the center of the assembly or assembly. Then, the assembly can be rotated to occupy the gaps or voids necessary for the expansion and contraction of the optical beams when the projector is in use.These known gaps have no useful function when the projector is not in operation and thus are available for the storage of components, such a feature allows to save a substantial volume of space, which makes the unit closed, compact and easily transportable.The screen assembly 40 does not have to be Rotationally mounted, for example, a bar link could be used to move it, but the rotating union is simpler. Along with the articulation of the screen, means can be provided to ensure the protection of the screen in storage or in use. These means may consist of movable fins or doors that provide a substantially contiguous outer shape when the unit is in use or in storage. As seen in Figures 2A and 2B, these doors include the doors 14 and 16, as well as the lower doors 54 and 56, all of which are rotatably joined to the body 12. When the screen assembly 40 is rotated to use, these doors move from one side to the other to allow passage. The doors not only protect the screen assembly and provide an aesthetically pleasing design, but also reduce light leakage. Each of the doors is preferably loaded by spring to automatically retract after rotation of the screen assembly 40 to the stowed position. The projection lens 42 can also be coupled to the screen assembly 40, such as by links 58, to automatically retract the projection lens 42, when the projector 10 is configured in the storage state (and to automatically extend the projection lens 42 out of body 12 when configured in the deployed state). The screen assembly 40 itself is preferably driven by an over-centered spring in which it is engaged by a latch attached to the button 18. This latch also fixes the apparatus when it is stowed (that is, it closes the doors 14, 16, 54 and 56). , and keeps the projection lens 42 retracted). A lens or iris cover (not shown) may also be provided to impart additional protection to the projection lens 42 when retracted. A lever (not visible in the figures) attached to one side of the body 12 and attached to the housing 52 of the display assembly can be used to simultaneously move all parts to the stowed position. Figures 2A and 2B also illustrate a set 60 of rear leg which, with the legs 62 formed on the lower retractable door 54, completes a tripod procedure to level the unit. It can be seen that in the deployed position, the screen assembly 40 rests on the legs 62 and also supports the body 12 and eliminates the need to fix the LCD module in an open position in the event that the machine slides by table. The leg assembly 60 includes the adjustment knob 20 which is fastened to a screw gear or threaded member 60 and a track or travel guide 66 having an end 68 formed in a leg. The rear end of the projector 10 can thus be raised or lifted by rotating the knob 20 clockwise to adjust the separation angle of the projection axis when the projector is resting on a surface (ie, to adjust the height of the projected image). As the knob is rotated in the counterclockwise direction the rear end will be decreased or lowered, the leg assembly 60 is advantageously provided with a feature that allows a quick release of the travel guide 66 and the retraction of the leg 68 in the body 12. The travel guide 66 fits a cavity or carrier formed in, or attached to the body 12, but does not rigidly attach thereto. Rather, it is provided with a sufficient tolerance to allow it to be removed from the worm gear 64. A spring attached to the travel guide 66 then retracts it automatically. The fraction of the spring actually retains the guide 66 against the gear 64, to prevent it from retracting under normal circumstances, but the user can press the knob 20 laterally to move the guide 66 away from the gear 64 and allow the spring I retracted it. With further reference to Figure 3, other components of the projector 10 can be seen. These include a second fan 70 for cooling the power source 44, a third fan 72 for cooling the optical module, which is surrounded by the heat sink 32. , for which conduction cooling and thermal convection and an optional speaker 74 are presented. The additional electronic components (LCD control) may be conventional and go beyond the scope of the present invention except that, consistent with the objective of compactness, the electronic components are preferably packaged in a relatively small subassembly or sub-assembly. An appropriate package is available from Neo Systems under model number MDI-0344 and includes data and video functionality to operate the LCD panel. With such commercially available components, the projector 10 is approximately 8.10 cm x 27.7 cm x 41.4 cm (3.4"x 10.9" x 16.3"), but with custom-made components, a smaller size of 8.3 cm x 26.7 is feasible. cm x 37.5 cm (3.25"x 10.5" x 14.75"). The projector 10 has a variety of advantages in addition to the compactness and ease of transportation. The simplicity of the optical components produces a light weight projector, to further improve portability. Due to the reduction in size, weight and number of components, a unit can be produced at relatively low cost without sacrificing performance. The projector can be electronically addressed and is capable of providing excellent image quality and brilliance. For storage, the main benefits conferred by this reconfiguration are the reduction of the total volume of the unit and the absence of protruding parts that could otherwise be damaged. A handle or carrying handle (not shown), can also be attached to the unit for easy transport when using only one hand. Since the unit is designed in such a way that it has a relatively uniform profile or exterior, it suffers less damage if it accidentally comes into forced contact with other objects and is less likely to interfere with the movement of the person transporting it. Finally, the self-deployment mechanism allows the user to adjust it quickly for its presentation, which improves its effectiveness. Although the invention has been described with reference to specific embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the described embodiment, also as alternative embodiments of the invention, will be made to those skilled in the art with reference to the description of the invention. It is therefore contemplated that such modifications may be made without departing from the spirit or scope of the present invention as defined in the appended claims.

It is noted that, in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers. Having described the invention as above, property is claimed as contained in the following

Claims (20)

1. Claims 1. A display device characterized in that it comprises: a light source; a montage or screen set that has means to create an image; means for directing light from the light source to the assembly or screen assembly, which define a direction of the light beam; a projection lens positioned to receive the image created by the assembly or screen assembly; and means for moving the display assembly or assembly from a storage position, in which the display assembly is generally parallel with the direction of the light beam, to a deployed position, in which the display assembly is arranged at an oblique angle with respect to the direction of the light beam. "2. The display device according to claim 1, characterized in that the means for directing light from the light source to the screen assembly include: a localized reflector. adjacent to the light source, opposite the mounting or screen assembly, and a condenser lens interposed between the light source and the display assembly or assembly 3. The display device according to claim 1, characterized in that the assembly or screen assembly includes a liquid crystal display panel 4. The display device according to claim 1, characterized in that the means for Moving the assembly or screen assembly allows the screen assembly to rotate between storage and deployed positions. The display device according to claim 1, characterized in that the oblique angle is approximately 90 °. 6. The display device according to claim 1, characterized by: the light source, the screen assembly or assembly, the light directing means and the projection lens are all located in a common body; and the means for moving the screen assembly or assembly also causes the projection lens to extend at least partially outwardly from the body in the deployed position and cause the projection lens to retract into the body in the stored position. . 7. The display device according to claim 1, characterized in that: the light source, the screen assembly, the means for directing the light and the projection lens are all located in a common body; the body has movable doors between an open position, when the screen assembly is in its unfolded position and a closed position when the screen assembly is in its stored position; and the screen set extends through the doors e? the position displayed. The display device according to claim 1, characterized in that the means for moving the screen assembly also provide means for modifying the shape of the image. 9. The display device according to claim 4, characterized in that the screen assembly rotates along an approximate centered line thereof. The screen device according to claim 7, characterized in that the screen assembly, when in its deployed position, is adapted to support the body. 11. A display device, characterized in that it comprises: a body; a light source located in the body; a projection lens located on the body, a line between the light source and the projection lens defines a projection axis; a mount or screen assembly having means for creating an image, the assembly or screen assembly is located on the body and interposed between the light source and the projection lens; and means for rotating the screen assembly or assembly from a storage position, in which the screen assembly is generally parallel with the projection axis, to a deployed position, in which the screen assembly is arranged at an oblique angle with respect to the projection axis. 12. The display device according to claim 11, characterized in that the display assembly includes a display panel-liquid crystal transmitter. The display device according to claim 11, characterized in that the means for moving the screen assembly also causes the projection lens to extend at least partially outwardly from the body in the deployed position and cause the lens of projection is retracted inside the body in the storage position. The screen device according to claim 11, characterized in that: the body has movable doors between an open position, when the screen assembly is in its unfolded position and a closed position, when the screen assembly is in your storage position; and the screen set extends through the doors e? the position displayed. 15. The screen device according to claim 11, characterized in that it further comprises means for adjusting a separation angle of the projection axis when the body is supported on a support surface. The display device according to claim 11, characterized in that the means for moving the screen assembly also provide means for modifying the shape of the image. 17. The display device according to claim 12, characterized in that the screen assembly rotates along an approximate center line of the liquid crystal display panel. 18. The display device according to claim 13, characterized by: the body has movable doors between an open position, when the screen assembly is in its unfolded position and a closed position, when the screen assembly is in its position storage; and the screen assembly extends through the doors in the deployed position. The screen device according to claim 15, characterized in that the screen assembly, when in its deployed position, is adapted to support the body. 20. An integrated, compact LCD (liquid crystal display) projector, characterized in that it comprises: a body having upper and lower surfaces generally planar and parallel, each of the upper and lower surfaces having at least one movable door between an open position and a closed position; a source of high intensity light located in the body; a projection lens located on the body, a line between the light source and the projection lens defines a projection axis; an assembly or screen assembly having means for creating an image, the assembly or screen assembly is located on the body and interposed between the light source and the projection lens and includes a transmitting liquid crystal display, electronically addressable; means for rotating the screen assembly, along an approximate center line thereof, from a storage position, in which the screen assembly is generally parallel with the projection axis, to a deployed position, in the as the screen assembly is disposed at an oblique angle with respect to the projection axis, the screen assembly extends through the doors of the body in the deployed position; means, linked to the rotating means, to cause the projection lens to extend at least partially outwardly of the body in the deployed position and to cause the projection lens to be retracted back into the interior of the body in the position of storage; and means for adjusting a separation angle of the projection axis when the body is supported on a support surface. SUMMARY OF THE INVENTION A liquid crystal display (46) projector (LCD projector) having a display unit consisting of a panel (46) of transmitting LCD and Fresnel lenses (48, 50) arranged on both is described. sides thereof, a light source projection unit (30, 34, 36, 38) for illuminating the screen and a projection lens (42) for projecting the light transmitted through the screen onto a projection screen. The panel (LCD) of the screen is arranged to articulate, rotate, between a storage position, in which the panel is parallel to the light path and an operative position, in which the panel is inclined or perpendicular to the path of light. (A small inclination that allows the correction of wedge distortion). The projector can be accommodated in a substantially rectangular flat housing having hinged covers (flaps) (14, 16, 54, 56) on its upper and lower walls, the covers are arranged to be opened in order to allow the panel to be opened. LCD extends beyond the walls of the housing when it is rotated in its operative position, such that in the storage position, the housing has a reduced size. The articulated or rotating movement of the LCD is coupled to the movement of the projection lens (42), which is retracted into the housing when the LCD is rotated in its storage position.