MXPA99010064A - Notebook size lcd projector - Google Patents

Abstract

A compact electronic projector (10) has separate optics and electronics compartments which are thermally and electromagnetically isolated from each other. In this manner closely spaced components are prevented from electrically or thermally interfering with each other, and high quality projected images can be maintained. The optics compartments contains a display assembly, such as a liquid crystal display panel (52) and associated Fresnel lenses, which is mounted inside the projector so as to rotate between a storage position in which the display assembly is generally parallel with the projection axis of the device, and an operational position in which the display assembly (50) is disposed at an oblique angle with relative to the projection axis. The assembly can thus be rotated to occupy the voids needed for expansion and contraction of the optical beams when the projector is in use, but which have no useful function when the projector is not in use.

Description

ANTI-SIZE LIQUID CRYSTAL DISPLAY PROJECTOR Champion of the Invention The present invention relates to projection systems, particularly to a compact, portable projector having an electronically steerable display device, such as a device for visual representation of liquid crystal (LCD, for its acronym in English). BACKGROUND OF THE INVENTION The introduction of portable computing devices such as suitcase computers and the development of presentation software, i? Sophisticated for use in computers has resulted in a need for similarly compact and portable projection devices for use in what is commonly known as an electronic presentation. A first and still common way of projecting an electronic presentation has been the use of a liquid crystal display (LCD) device panel, such as is illustrated in U.S. Patent No. 4,719,547, on a projection path projector high, conventional (OHP, for its acronym in English). These panels are aimed REF: 031763 electronically, that is, the appearance of the final image is controlled by electronic signals sent to the panel. Electronic signals can come from a computer, or they can be normal video signals (NTSC), or other suitable devices. The use of such an LCD panel is illustrated in U.S. Patent Nos. 5,231,434 and 4,846,694. The LCD panel and the high projection path projector are independent devices used together for the duration of the presentation only. The LCD panel is placed in the stage of the high projection path projector, and the light passing from the stage through the LCD panel is projected onto a focusing surface by the high projection path projector. As the convenience of electronically generated and stored presentations has come to be appreciated, a new class of presentation devices has appeared, often referred to as "integrated projectors." An integrated projector unit is able to take input from a computer or other source of signals and project an image on a screen. Integrated, modern projectors are capable of projecting useful images even in high ambient light conditions. Such units have developed a patent literature of their property, a few examples of which are summarized below. U.S. Patent No. 4,943,154 shows a projector having three "light valves" (a particular form of a liquid crystal display device, steerable), and a complicated optical path proposed to allow the output of a soft light source to be divided into red, green and blue components, formed in image with the three light valves (one for each color) and then recombined for the projection, through an individual lens. Such optical systems are complicated to manufacture, assemble and maintain, occupy a considerable amount of space, weigh a substantial amount, and have potential efficiency problems. Other examples of this type of device are illustrated in U.S. Patent Nos. 5,374,968 and 4,018, 509. An alternative method of projecting an image is to have a single LCD panel, an optical path and lenses, and to interpose the filters in succession. red, green and blue. When 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 easily respond to the change of input signals. These also need a well-designed filter wheel and associated physical elements. For these reasons this method has found little use. 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 display device, and these filters are routed appropriately by the liquid crystal array mounted to register with them. This type of LCD, while being slightly more complicated to manufacture, has the disadvantage of needing only an individual optical system. In addition, the filters and control elements can never lose alignment, and the weight of the LCD needs to be little more than the weight of an individual color unit, to economize in this way in weight and space. The additional weight savings are also achieved in the elimination of prisms, filters, mirrors, etc., and their assemblies. U.S. Patent No. 5,321,450 describes a projector that exemplifies these principles. Through the use of mirrors and an angled LCD, a low profile is achieved. A lens having its optical axis vertically arranged for projection is used, and a final mirror (which can be lowered) directs the light along a horizontal path. This mirror is the only component that moves for storage, and space saving is less. Another such device is illustrated in U.S. Patent Number 4,971,436 which shows a light source, a transmission LCD panel and a projection lens. Also illustrated in this patent are bent optical elements which are desirable to reduce the total volume or the footprint of the unit. There are limitations for the reduction of additional size in these devices. As the requirements for high brightness projectors evolve, more powerful light sources must be incorporated. When strong sources must be incorporated into small-sized devices, problems arise in the removal of residual heat (generated by most light sources, and particularly by sources of tungsten filament, quartz-halogen and arc sources). In this way, efficient heat removal systems should be designated. Also, there is a very substantial damage that the heat generated by the light source will cause a degradation of the performance of the sensitive electronic components necessary for the operation of these devices. The North American patent No. ,313,234 addresses this problem by designing compartments for "heat" and "cold." The source of the lamp and the cooling medium are contained in the compartment for "heat", while the LCD panel and the projection lens are contained in the compartment for the "cold". The related and co-pending US applications Serial Number 08 / 673,292, North American Serial Number 08 / 623,729 and North American Serial Number 08 / 787,075, owned by the assignee of the present application, describe additional ways to reduce the size of such projectors. US Application Serial No. 08 / 673,292 discloses an efficient lamp cooling means that allows the placement of the LCD panels in close proximity to strong light sources. U.S. Application Serial No. 08 / 623,729 and U.S. Application Serial No. 08 / 787,075 describe a means for rotating the LCD between a storage position and an operative position, thereby reducing the storage volume of the projector. It is possible, by these means, to produce suitably sized projectors which are easily portable and even capable of excellent optical performance.

However, as the size of the integrated projectors decreases, new problems arise. In particular, the close proximity of the electronic, sensitive components and the powerful light sources provides the opportunity for undesired thermal and electromagnetic interactions between the components to occur. These interactions are capable of degrading the performance of the projector system to such an extent that it is unacceptable for high-quality presentations. It would therefore be desirable and advantageous to devise an integrated, compact and portable projector which takes advantage of unused space within the projector, which minimizes electromagnetic and thermal interference between the components, and which allows rapid and easy deployment for the use.

Brief Description of the Invention The present invention provides an integrated, compact projector for electronic presentations. The projector generally comprises a housing with a compartment for optical elements and a compartment for electronic elements within the housing, wherein the compartment for optical elements and the compartment for electronic elements are electrically and thermally protected from each other. In this way, electromagnetic and thermal interference between the optical elements and the electronic elements of the projector is avoided. The compartment for optical elements contains a mounting of optical elements for creating and projecting an image, where the mounting of optical elements generally includes a light source, a visual representation assembly having a means for creating an image, a means for directing the light from the light source to the visual representation assembly, and a projection lens positioned to receive the image created by the visual representation assembly. The visual representation assembly may take the form of a transmissive liquid crystal display panel. The compartment for electronic elements contains an electrical assembly for operating the light source and the visual representation assembly. The projector has a storage / transport configuration and an operational configuration. The display assembly can be moved correspondingly between a storage position and an operative position. The display panel is generally parallel with the projection axis when in a storage position, and normal to the projection axis when in an operative position. When the display panel is in an operative position, a compartment door for optical elements is opened to expose the projection lens, such that the projection lens is placed at an inclined angle relative to the projector's support surface. The invention provides an electronically steerable projector that is capable of providing excellent image quality and brightness. The projector can be easily reconfigured for compact storage and easy transport.

Brief Description of the Drawings Figures IA and IB are perspective views of the preferred embodiment of the projector in a storage / transport configuration. Figures 2A and 2B are perspective views of the preferred embodiment of the projector in an operational configuration. Figure 3 is a plan view of the projector of Figures IA and IB, taken in the direction of line 3-3 in Figure IA. Figure 4 is an elevational view of the projector in a storage / transport configuration taken along line 4-4 in Figure 3. Figure 5 is an elevation view of the projector of Figure 4 in an operational configuration . Figure 6 is an elongated and isolated view of the optical assembly of the projector in an operational configuration.

Detailed Description of the Invention A preferred embodiment of the compact projector 10 is seen in Figures IA, IB, 2A and 2B. Figures IA and IB show the preferred embodiment of the projector 10 in its closed or storage configuration, while Figures 2A and 2B show the projector 10 in its open or operative configuration. The projector 10 includes a case or body 12, a retractable door 14, a driving lever or button 16 for operating the door 14, a receptacle 18 for a power supply cable (not shown), a power switch (on / off) 20, a focus adjustment wheel 22, a control panel 24, and one or more holes providing various types of electrical connectivity (such as video and data controllers), each indicated as 26. To change the projector 10 of its storage configuration (Figures IA and IB) to its operational configuration (Figures 2 and 2B), the lever 16 is driven to lift from the door 14 and reveal the projection lens 28. In this embodiment, the body 12 it is similar to a box and its top surface (which includes the retractable door 14) is flat and generally parallel with its bottom, flat surface when the projector 10 is in the storage configuration shown in Figures IA and IB. This shape provides a particularly low profile, but those skilled in the art will appreciate that other profiles can be provided which are not as rectangular as the projector 10. The body 12 can be constructed of any durable material, preferably a weight polymer lightweight such as acrylonitrile butadiene styrene (ABS) or polycarbonate. Figure 3 is a plan view of the projector 10 taken in the direction of lines 3-3 in Figure IA, which represents the projector 10 in its storage / transport configuration. Figure 3 shows that the interior of the projector 10 is divided into two compartments: a compartment for optical elements 30 and a compartment for electronic elements 32. The compartment for optical elements 30 and the compartment for electronic elements 32 are physically separated by the wall 34. and they are also thermally and electromagnetically protected from each other by the electromagnetic protection material 36, such as conductive elastomer gaskets made by Chomerics. Such electromagnetic shielding material 36 will typically be spread over all sides of the compartments 30, 32, as well as the top and bottom portions of the compartments 30, 32. However, electromagnetic shielding does not need to encircle both the element compartment. opticals 30 and the electronic element compartment 32. Since the compartments 30, 32 are protected from each other, the electromagnetic protection could encircle only one of the compartments 30, 32. If substantial interference from other devices is expected in the vicinity of the projector 10 , it may be desirable to have both compartments 30, 32 protected, as illustrated in the figures. Of course, it is not possible to completely insulate the compartments 30 thermally and electromagnetically32. Therefore, the degree of protection between the compartments 30, 32 needs to be only sufficient to prevent any degradation of the performance of the projector 10. Within the compartment for optical elements 30, the projector 10 is additionally comprised of a light source 40. , a collimator (parabolic reflector) 42 and a condenser lens 44 positioned opposite to the light source 40, an infrared filter (hot mirror) 46 proximate the condenser lens 44, a display assembly 50, and a previously mentioned projection lens 28. The projection lens 28 is adjusted with the focus adjustment wheel 22 and the focusing mechanism 48. All of these components are located in the optical element compartment 30 of the body 12 although, as described subsequently, the display assembly 50 and the projection lens 28 protrude above the upper surface of the body 12 when the project Tor 10 is in its operational configuration. The light source 40 is preferably a high intensity source such as an EVD lamp (halogen) or a series of high-output metal halide lamps (for example 250 times, 400 watts, 575 watts) available from Osram (part of Sylvania Co. of Germany) or- Philips Electronics of the Netherlands.

This is connected to a 12 volt DC power source located in the electronics compartment 32 of the body 12. Other suitable light sources, such as a reflector lamp, could also be used, if desired. The condenser lens 44 is preferably planar-convex and is constructed of a borosilicate glass such as Pyrex (a trademark of Corning, Inc.). The infrared filter 46 is a conventional hot mirror such as those available from Bausch & Lomb. The display assembly 50 may take various forms, such as a transmissive LCD panel, a light valve, or a microseep array. In the preferred embodiment of the projector 10, the display assembly 50 includes an LCD panel 52 such as the 16.3 cm (6.4") panel (or smaller scale) available from Sharp of Japan, and two Fresnel lenses 54 and 56, secured in a housing 58. The display assembly 50 is pivotally or rotatably joined to the interior of the body 12 in such a way that, in the operating state, the display assembly 50 is perpendicular in general to the path of light, but in the storage state it is generally parallel to the light path and occupies the space reserved for the cone of light (the gaps needed for the expansion and contraction of the optical beams when the projector is in use) During the operation, these gaps have no useful function when the projector is not in operation, and thus are available for the storage of the component, which makes it possible to save a volume substantial space, to make the unit compact and easily transported. Those skilled in the art will recognize that a variety of mechanisms will work to move the display assembly 50 from a storage position to an operational position. For example, the display assembly 50 does not have to be rotatably mounted, for example, a bar link could be used to move the display assembly 50 from its storage operation to its operational position. Those skilled in the art will also recognize that if the display assembly 50 is sufficiently small (or the body 12 large enough), it would be possible to mount the display assembly 50 in a fixed position, such that there is no movement of the display assembly. visual 50 between a storage position and an operational position as described above, if necessary. A "fixed" installation of the display assembly 50 is contemplated to be within the scope of this application, as such a configuration would still benefit from the present invention. With reference to the Figures, the term "light path" is used to describe a direction of the projector that coincides with the projection axis, i.e., the generally straight line between the light source 40 and the projection lens 28. This term is appropriate for the particular modality represented, but should not be constructed in a limiting sense. Other modalities may employ bent optical paths such as by the use of mirrors, catadioptic Fresnel lenses, etc. and (while these components may 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. Also, while it is certainly preferable to have light striking the LCD panel at a generally normal angle during use, this is not a critical requirement. If the light hits the display panel 50 at an oblique but not orthogonal angle, the shape of the image can be corrected through the selection of the angle of rotation of the visual representation panel. The placement of all the optical components in a single compartment provides significant advantages for the projector 10. Mainly, the optical components are in a movable but rigidly aligned relationship, such that the spatial orientation between the optical components does not vary when the user changes the projector 10 from the storage / transport configuration to the operational configuration. Spatial, fixed orientation ensures that the quality of the projected image remains at a high level. The advantages of the projector 10 can easily be observed in the transition of the projector 10 from its storage / transport configuration to its operational configuration, as described below. Figure 4 shows a side view of the optical components in the compartment for optical elements 30 corresponding to the plan view of Figure 3. The projector 10 is in its storage / transport configuration, and the plane of the display assembly 50 is in alignment generally parallel with the path of light between the light source 40 and the projection lens 28. The light source 40 and the associated collimator 42, the condenser lens 44 and the infrared filter 46 are fixedly oriented in a inclined angle relative to the base plate 60 of the body 12. The conduit 62 surrounding the light source 40 can be observed, as can be seen the heat dissipating elements 64 which help the cooling of the light source 40. The thermal management of the light source is described in co-pending US patent application and co-owned Serial No. 08 / 673,292, which is incorporated by reference. The door 12 is hinged to the body 12 in the hinge 66, and the walls of the compartment for optical, movable elements 68 (which operate as a part of the door 14) can also be observed. The walls of the compartment for optical, movable elements 68 are provided to prevent the escape of light from the interior of the optical compartment 30 when the projector 10 is placed in its operational configuration. The projection lens 28, the focusing mechanism 48, and the focusing adjustment wheel 22 are fixedly attached to the interior of the door 14 and move together with the door 14. As best seen in Figure 5, when the lever 16 is driven by a user, the display assembly 50 is rotated such that the light path is approximately orthogonal to the plane of the display assembly 50. As the display assembly 50 rotates in its operational, door position 14, the projection lens 28 and the focusing mechanism 48 move to a pre-set, high position, such that the projection lens 28 is generally aligned with the inclined angle of the light source 40. Then the projector 10 is ready for use. When the use of the projector 10 is complete, the user can change the projector 10 back to its storage / transport configuration by simply rotating the display assembly back to its storage position. The door 14 is preferably driven by a spring to automatically retract with the rotation of the display assembly 50 to the storage position. It should be noted that the plane of the visual representation assembly 50 can be deviated from an orthogonal orientation with respect to the light path intentionally, for example to correct the optical effect known as "trapezoidal effect". The trapezoidal effect is a distortion of the image observed when the target plane of an optical system, in this case the LCD panel 52, and the projection screen (not shown) are not parallel. The trapezoidal effect was observed as a difference in the dimensions of the upper and lower links of the projected image, whereas in the objective to be projected, the dimensions are identical or very close. Figure 6 shows an enlarged side view of the optical components placed in the operational configuration. An optical axis 70 of the projection lens 28 is shown, as is the axis 72 joining the light source 40 to the center of the LCD panel 52. It should be noted that the optical axis 70 and the axis 72 are not co-operative. linear The purpose of non-linearity is to reduce the trapezoidal effect of the projected image. The compartment for electronic elements 32 contains such components as the power source 80, the ignition apparatus 82 for the arc light source 40, the printed circuit board 84, and the electronic data access connections 26. Naturally, depending on the desired functions of the projector 10, numerous other variations and arrangements of components will be apparent to those skilled in the art. In general, it is desirable to place the electronic components which are adversely affected by excessive thermal or electromagnetic interference in the electronics compartment 32. Access is necessary between the exterior of the projector 10 and the compartments 30, 32 and between the compartments 30 and 32 for the cold air flow. For this reason, access holes 90 are provided in body 12 and wall 34. Access ports 90 are preferably covered by filters (not shown) that have the ability to remove suspended particles in the air and also They have electromagnetic protection properties. Such filters are available from, for example, Tetko Inc. of New York_ and Delker Corporation. To assist the flow of cooling air through the compartments 30, 32, the light source 40 is contained in the conduit housing 62 which serves to draw air through the optical element compartment 30 by means of a fan 92. , the conduit housing 62 which is designed to vent hot air to the exterior of the body 12. As shown in Figure 3, one or more auxiliary fans 94 may also be provided to withdraw the cooling air through the compartments 30. , 32 of the projector 10, for example to cool the display assembly 50. In the preferred embodiment, the fans 92, 94 remove air from the exterior of the body 12 in the electronic component compartments 32, and then in the component compartments. optical 30. This cooling air circulation brings the cold lower air (outside) first on the heat-sensitive electronic component, and then on the hottest optical compartment, such that the most efficient cooling of each compartment is achieved. Of course, another airflow pattern can be devised which also provides adequate cooling of the projector 10. Additional features of the projector 10 are seen in Figure 31. In particular, the projector 10 can also be equipped for the portion of Audio of audio-visual electronic presentations. For this purpose, the projector 10 is provided with a loudspeaker 96. The loudspeaker 96 is shown installed on the rear panel of the body 12 within the compartment for optical elements 30, such that the sound generated by the loudspeaker 96 comes out of the perforations 98 in the body 12 towards the spectator audience, which is typically seated behind the projector 10. However, the speaker 96 can also be located in the electronics compartment 30, or it could be completely removed from the projector 10. The projector 12 could also be equipped with the data accesses 26 suitable for connection to external loudspeakers. The projector 10 has a number of advantages in addition to the compactness and ease of transportation. The simplicity of the optical components produces a lightweight projector, also increases portability. Due to the reduction in size, weight and number of components, a unit can be produced at a relatively low cost without sacrificing performance. The projector can be electronically steered and is capable of providing excellent image quality and brightness. For storage, the primary advantages are the reduction of the total volume of the unit and the absence of protruding parts that could otherwise be damaged. The mode of the projector 10 described above has a volume in the range of 508 to 762 cubic centimeters (200 to 300 cubic inches) and preferably has dimensions of approximately 6.35 centimeters x 22.83 centimeters x 25.4 centimeters (2.5 inches x 9 inches x 10 inches) for a volume of less than 635 cubic centimeters (250 cubic inches). The size of the unit can be further reduced when introducing smaller LCD panels. A carrying handle (not shown) could also be attached to the unit for easy transport using only one hand. Since the unit is designed to have a relatively smooth exterior, it suffers less damage if it accidentally comes in strong contact with other targets, and is less likely to interfere with the movement of the person carrying the unit. Finally, the automatic deployment mechanism allows the user to install quickly for a presentation, thus increasing the effectiveness of the unit. Although this invention has been described with reference to specific embodiments, this description should not be constructed in a limiting sense. Modifications and alterations of the described modality will be apparent to those skilled in the art with reference to the description of the invention. It is contemplated that such modifications may be made without departing from the spirit and scope of the present invention as defined in the 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 relates.

Having described the invention as above, property is claimed as contained in the following:

Claims (19)

1. CLAIMS i- A battle device or visual representation, characterized in that it comprises; accommodation; a compartment for optical elements within the housing, the compartment for optical elements containing a mounting of optical elements to create and project an image; a compartment for electronic elements inside the housing, the compartment for electronic elements that contains an electrical assembly to operate the assembly of optical elements; wherein the compartment for optical elements and the compartment for electronic elements are electrically and thermally protected from each other.
2. 2. The visual representation device according to claim 1, characterized in that the assembly of optical elements comprises: a light source; a visual representation assembly having a means for creating an image; means for directing light from the light source to the visual representation assembly, which defines a direction of the light beam; and a projection lens positioned to receive the image created by the visual representation assembly.
3. 3. The visual representation device according to claim 1, characterized in that it also comprises a loudspeaker.
4. 4. The visual representation device according to claim 2, characterized in that the electrical system includes a printed electronic circuit board for operating the visual representation assembly and the light source.
5. 5. The visual representation device according to claim 2, characterized in that the visual representation assembly is adapted to move from a storage position in which the visual representation assembly is generally parallel with the direction of the light beam, to a operative position in which the visual representation assembly is placed at an oblique angle with respect to the direction of the light beam.
6. 6. The visual representation device according to claim 2, characterized in that the compartment for optical elements is adapted to move from a storage position to an operative position.
7. 7. The visual representation device according to claim 2, characterized in that the means for directing light from the light source to the visual representation assembly includes: a reflector positioned adjacent to the light source, opposite the visual representation assembly; and a condensing lens interposed between the light source and the visual representation assembly.
8. 8. The visual representation device according to claim 2, characterized in that the visual representation assembly includes a liquid crystal display panel.
9. 9. The visual representation device according to claim 5, characterized in that the visual representation assembly is adapted to rotate from a storage position to an operative position.
10. 10. The visual representation device according to claim 5, characterized in that the oblique angle is approximately 90 °.
11. 11. The visual representation device according to claim 6, characterized in that the compartment for optical elements includes a door movable between a storage position and an operative position, and wherein the projection lens is hidden when the door is in a position of storage and is exposed when the door is in an operative position.
12. 12. The visual representation device according to claim 1, characterized in that the housing has a volume of less than 762 cubic centimeters (300 cubic inches).
13. 13. The visual representation device according to claim 1, characterized in that the housing has a volume of less than 635 cubic centimeters (250 cubic inches).
14. An LCD projector, characterized in that it comprises: a housing having a lower, flat surface and an upper surface generally parallel to the lower surface; a compartment for optical elements within the housing containing a light source, a display assembly having a means for creating an image, a half pair directing light from the light source to the display assembly, the means for directing the light defining a direction of the light beam, and a projection lens positioned to receive the image created by the visual representation assembly; a compartment for electronic elements inside the housing that contains an assembly of electronic elements for operating the light source and the visual representation assembly, the compartment for electronic elements is electromagnetically and thermally isolated from the compartment for optical elements; and a door within the upper surface of the housing, the door is continued with the compartment for optical elements and is movable between a storage position in which the door is flush with the upper surface of the housing, an operative position in which the The door extends above the upper surface of the housing to expose the projection lens.
15. 15. The LCD projector according to claim 14, characterized in that the display assembly is adapted to move from a storage position in which the display assembly is generally parallel with the direction of the light beam, to a position operative in which the visual representation assembly is positioned at an oblique angle with respect to the direction of the light beam.
16. 16. The LCD projector according to claim 15, characterized in that the means for directing light from the light source to the display assembly includes: a reflector positioned adjacent to the observation source, opposite the visual display assembly; and a condenser lens interposed between the observation source and the visual representation assembly.
17. 17. The LCD projector according to claim 14, characterized in that a line between the light source and the projection lens defines a projection axis, and wherein when the door is in an operative position a pitch angle of the projection axis it is inclined above the plane of the upper housing surface.
18. 18. The LCD projector according to claim 17, characterized in that when the door is in a storage position, the pitch angle of the projection axis is below the plane of the upper housing surface.
19. 19. The LCD projector according to claim 14, characterized in that the housing has a volume of less than 762 cubic centimeters (300 cubic inches).