WO2005122559A1 - Constructive device introduced in laser image projector - Google Patents

Abstract

Constructive device introduced in laser image projector, represented by an innovative and revolutionary solution in terms of image projection, representing great advantages compared with image projectors in prior art, such as TV sets HDTV, computer monitors, digital movie screens, digital lettering in stores, outdoors, HMD, HDHMD, among other, sine said innovation enables the miniaturization of all components necessary for the image’s projection, thus providing explicit gains in terms of the device’s portability, with greatly reduced weight, also representing a significant reduction in cost of manufacturing and utilization. The device claimed herein is based on a device that, on receiving a video signal (1), demodulates it, converting it into variations in the emitting power of laser beams (RGB-red, green and blue) through a process of intensity modulation, which proceeds to an xy rasterizer (5)- this modulation can be made by a direct (4.1) or post- (4.2) modulator. The xy rasterizing element (5) scans the laser beam, composing an image that is projected onto a screen (7) and is continuously corrected and tuned by means of deviation and intensity sensors (6).

Description

"CONSTRUCTIVE DEVICE

INTRODUCED IN LASER IMAGE PROJECTOR" This invention^' patent request discusses a "CONSTRUCTIVE DEVICE INTRODUCED IN LASER IMAGE PROJECTOR" , in which the applicant presents a solution with inventive features that allow, through a single projecting device, the emission of images (static or dynamic) , being that said device has a constructive and functional design that allows its manufacture in industrial scale at extremely low costs, hereafter referred to as LTV (Laser TV) . In relation to the innovated constructive design, the applicant makes use of technology available in the area of electrical-electronics with laser technology according to prior art . At least two technologies that can be used in the invention claimed are presented herein, one employing MEMS technology and the other conventional optical technology itself, in which one or more mirrors are used for rasterization of laser beams in image formation. The technology known as MEMS (Micro-Electro-Mechanical Systems) is based on the integration of several mechanical elements, sensors, and electronic components in a common silicon substrate, obtained through micro manufacturing technology. Since this technology is based on manufacturing techniques similar to those already used in the manufacturing of microcircuits, it brings high levels of functionality, reliability and sophistication, all inside a silicon microchip, a fact that reduces the cost factor to minimal levels for large-scale production, making it commercially feasible. The degree of miniaturization obtained with this technology allows reducing the entire device to a single chip, making it ultra-portable with less than 1cm³, such that it can be integrated in countless portable devices, like PDAs, Notebooks, enabling the creation of new product categories like ultra-portable image projectors or TVs, screens for devices for which the cost or miniaturization today renders them commercially unfeasible. In terms of consumption, for an MEMS version for the invention claimed herein, it would be extremely low, in the order of tenths of m , making it operable for several continuous days with batteries that are available in the market. Still within the scope of the constructive design, the solution claimed, due to its greatly reduced size, also adds value in terms of lightness and portability, such that the user can easily carry it. The obtainment of images by laser rasterization using conventional optical technology, in which vibrating or rotating mirrors are used, does not move out of the scope of this invention patent. This level of technology allows a degree of miniaturization in a portable equipment smaller than 1,000cm³ (cubic centimeters), in addition to a low consumption, being operable for hours with present day batteries . In relation to the innovated functional design, the applicant was able to add value in several aspects for, by making use of microchip technology, encapsulating innumerous technologies like laser in combination with MEMS and digital circuits like DSP, CPU and Flash memory and RAM into one or more integrated units, a final product was obtained with greatly reduced energy consumption and physical size. In times of scarce energy, especially electrical power, the laser image projector claimed herein meets the main requirement for products of this nature, which is low energy consumption. The claimed solution's low energy consumption will provide consumers with a nominal economy in the monthly power consumption. Considering the cascade effect that this discovery represents in the global reduction of electric power consumption, the product object of this invention patent application also provides great gains in the strategic planning of nations, for the maintenance of current and future demands for this type of power. As is known from prior art, static or dynamic image projectors are based on a technology grounded on constructive and functional designs in which mechanical, electrical and electronic based technologies are applied, oftentimes combined with the use of very old technologies like filament lamps or valves in which, to obtain the desired result in the projection of an image, a very significant amount of energy is lost. Only by way of explanation, for an image projection using convention projectors, the energy present at the end of this projection represents not more than thirty percent of the total energy supplied by the equipment . One can conclude that current image projectors have significantly low energy efficiency when compared to the object of this patent application in obtaining the desired final result. Also considering, for example, an equipment like "Data Show" in which the larger the image desired, the greater the energy of the light source should be. In the case of a filament lamp, the energy spent in conducting large exposures represents a high-energy consumption, without mentioning that said high brilliance lamps have a very reduced MTTF (Mean Time Till Failure) . For an image projector, the consumption of 185 watts to 3750 watts is extremely high. It is also pointed out that the lamps have extremely short durability in this type of projector when compared with the durability of a so-called solid-state system such as the silicon chip like the one presented. Still in prior art, there are image profile projectors very common in commercial entertainment events, in which laser technology is used for spatial projection of these profiles. In this specific case, the technology is limited to the projection of profiles, and reproduction of rasterized images is not possible, such as those transmitted by a television. Television sets use the kinescope component as image projecting technology. In this case, the size of the image to be generated is limited to the size of the kinescope itself (image tube made mainly from glass) , generally known in inches. The aggravator for the case of televisions resides precisely in the fact that the larger the image, the larger will be its respective kinescope, rendering its production very difficult and increasing its weight and mechanical fragility, the increase in energy consumption will be directly proportional to the kinescope's size, bringing limitations in residential use in relation to physical space and electric power consumption. The applicant, in view of the negative aspects ascertained for products intended for image projection, known in prior art, understands the solution claimed herein to be of extreme value, considering economical aspects of energy consumption both at individual and global level . The innovated device's portability meets the needs of users, who are eager for a device they can take along with them that provides all image viewing benefits wherever they may be. Apart from the economical aspect involved, the applicant reminds there is also an

ecological aspect, since the energy economy provided by the innovated device ensures that the environment does not suffer greater aggressions in the search for new energy sources to meet the growing needs of its consumption. By all of the above aspects, the applicant understands that the solution claimed herein represents an innovation in relation to the solutions in prior art, notedly in the area of application for the industry of static or dynamic image devices, such as: TV sets, HDTV, computer monitors, digital movie screen, digital lettering in stores, outdoors, HMD, HDHMD, among others. The constructive and functional designs claimed herein are extremely simple, enabling the reception and later projection of static or dynamic images, where the laser projection system enables the resulting device to have greatly reduced dimensions, since all components responsible for the stages of reception and projection can be miniaturized in a microchip. The LTV laser system scans the images received. It is worth point out that laser beam production technology is a field under development by the optics industry, offered in different functional designs, differentiated by the various active mediums, which can be solid or gaseous, the laser in solid state standing out from others due to its use of widespread semiconductor technology that can be mass produced at low cost . The laser's cost and duration depends on the wavelength (its color) - the shorter the wavelength (from the longer to the shorter we have infrared, red, yellow, green, blue, violet, ultraviolet) , the more complex are the materials and technologies involved in its production, thus increasing its cost. Therefore, red lasers are the cheapest and most accessible, since those of green light occupy an intermediary position in terms of cost, and the blue ones are quite more expensive. The red laser is the most commonly used, and is widely applied in devices of various natures in the field of commerce, industry and even medicine . The applicant also points out that, as is widely known in the field of microelectronics, the cost of new laser technologies tends to fall just as its service life tends to increase with time; if the product is not feasible now, it is only a matter of time for it to be. For the device to guarantee an image transmission in today's required standards, in which colored image is a mandatory requisite, the applicant foresees in the LTV the use of red, green and blue light emitting lasers, thus enabling the formation of images within the known RGB standard or in other color systems . The laser emitter set can comprise only one laser, in the case of monochromatic projection systems, two or three laser emitters of different colors for colored systems, or even a liner or 2D linear matrix of lasers in which whole lines, or even multiple image lines, are produced simultaneously. The applicant foresees in the initial stages, the development of LTV versions using only red laser, any later maybe green, be it due to initial cost limitation or for purposes that do not require high-fidelity color images, like displays with product prices in stores, projection of information with mostly alphanumeric characters or with simple images . Considering the fact that the laser beam's light intensity must be modulated (have its intensity varied from time to time) - a basic requisite for an adequate image composition, the applicant foresees the use of a modulator, being that the constructive design of the laser image projector foresees two possibilities for the use of modulators . Direct modulation, whose functional principle lies in varying the emitting power of each laser beam through its respective supply circuits . This direct modulation variation is the one with the best energy efficiency relation. A second variation of the modulator is uses what is called post-modulation, and leaves the lasers constantly active with constant emitting power, and after emission, makes use of liquid crystals, GLVs

(Grating Light Valve) , DMDs (Digital Micromirror Device) or piezoelectric modulators to attenuate or deviate part of the light produced, however, they are not as efficient as direct modulation. Once modulated, the laser beams are directed to the rasterizer, responsible for effectively composing the image. Xy rasterizers can be provided with different constructive and functional designs, like those whose constructive designs are provided with micromirrors - MEMS . Its greatest advantage is the low cost involved, great miniaturization and mass production, such as in the integrated circuit industry. The applicant considers in his invention the possibility of using other types of xy rasterizers. We can mention the rasterizer with one or more mirrors, which is based on a motion system of small mirrors, which move to generate the image composition, or a single mirror that is deviated in two angles with perpendicular rotation axes, a motion that can be obtained through rotating, mirrored, polygonal cylinders. During rasterization, the image is constantly compensated through a feedback system (re-feeding) , which continuously adjusts beam intensity and parameters of the of xy rasterization mechanical drives. For image compensation, the applicant foresees a light sensing element in the constructive design of the laser image projector, which can use any light or image sensing technology, CCD (Charge

Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) technology, among others, the latter having an advantage in terms of low cost and electronic integration, or sensors can have a single element, one line or one matrix, the latter allowing the compensation of a larger number of anomalies in the operation and further improving image quality. The applicant reminds that the image is continuously corrected during its production, line by line, point to point. This continuous feedback process by the image sensors and processed by the DSP and CPU signal processing block ensures that the image is compensated to overcome many types of anomalies that may arise due to problems of internal and external adjustments, making the equipment more robust to unpredictable events . The image can be projected onto a screen on an ordinary wall, on screens for overhead projectors, data show, movie, own screens, rear (transmitting) and front (reflecting) transmission screens, in addition to the possibility of transmission directly on the retina (in cases of HMD, or medical cases) . The following are attached herewith to complement this description for better understanding of this patent claim's features: a set of simple and illustrative (but not limitative) diagrams: Figure 1 is a representative diagram of the laser image projector (LTV) , considering the direct modulation variant, Figure 2 is a representative diagram of the laser image projector (LTV), considering the post-modulation variant . With reference to the drawings shown, this invention patent application refers to a "CONSTRUCTIVE DEVICE INTRODUCED IN LASER IMAGE PROJECTOR" , where figure 1 shows its constructive and functional design considering a direct modulation, in which the generic video signal 1 is received by the device, and is processed through digital processing systems like DSP, CPU, RAM and FLASH memory 2. The block 2 controls the emitting power of each laser beam 3 through the direct modulator block 4.1. The laser beam made up of the sura of several beams is directed toward an xy rasterizing element 5, which is responsible for the scanning process of the beam on the screen, producing an image corresponding to that received by the original video signal 1. During scanning of the image by the xy rasterizer 5, the image must be compensated, and through the deviation sensor 6, which is the light sensor previously discussed, it delivers several information (on timing, intensity, laser response linearity, etc., on each laser element) to the information processing block 2, where it will be processed and the due corrections made in the following pixels. The beam is projected simultaneously onto a screen 7. The variant foreseen for the

LTV with post-modulation is detailed in the diagram in figure 2, where it differs from the first case merely by the fact that the laser beam is post-modulated through a post- modulation element 4.2.

Claims

CLAIM "CONSTRUCTIVE DEVICE

INTRODUCED IN LASER IMAGE PROJECTOR" aiming at developing a totally unprecedented device that projects images by means of an extremely small, portable and light device with reduced energy consumption, characterized by a laser image projector with direct modulation or post-modulation variant, where the generic video signal (1) is received by the device, and is processed by signal processing electronic systems (2) (DSP, CPU, RAM and FLASH memory) , which by their turn control the laser (3) (RGB) emitting elements (or matrix) , converting the video signal into variations in the emitting power of each laser beam, which can be modulated directly through a direct intensity modulator (4.1) or later through a post-modulator (4.2), and which is then directed to an xy rasterizing element (5) that scans the beam (sum of all the lasers) composing an image, which simultaneously undergoes a process of compensation by a deviation sensor

(6), and is projected onto a screen (7) .