KR100814833B1 - A projection system using led arrays as light sources - Google Patents

Abstract

The structure of the three-panel projection system of the present invention comprises: a red LCD panel, a green LCD panel, and a blue LCD panel which separate only the red component, the green component, and the blue component with respect to an image to be displayed and process each signal only; A red light emitting device array, a green light emitting device array, and a blue light emitting device array disposed on a rear surface of each of the red LCD panel, the green LCD panel, and the blue LCD panel, respectively, to emit red, green, and blue light; Optical composite means for receiving the red, green, and blue light emitted from the respective light emitting element arrays through the corresponding LCD panels, receiving all of them, and integrating them to project the image in a projection method; An LCD panel driver for controlling each LCD panel; And a light emitting device array driver for controlling driving of each light emitting device of the light emitting device array. The LCD panel driver sequentially activates each pixel constituting the LCD panel, and the light emitting element array driver drives the light emitting element closest to the activated pixel of the LCD panel in synchronization with the activation time of the pixel, thereby allowing the LCD to be driven. Each light emitting device constituting the light emitting device array is sequentially driven in synchronization with the activity of the corresponding pixel of the panel.

Description

Projection system using LED array as light source {A PROJECTION SYSTEM USING LED ARRAYS AS LIGHT SOURCES}

1 is a diagram schematically showing the structure of a conventional projector.

2 is a diagram schematically showing the structure of a three-plate projection system of the present invention.

3 is a block diagram of a three-plate projection system of the present invention.

4 is a view showing a driving method of an LCD panel.

5 illustrates the correspondence between LCD pixels and LED chips.

6 illustrates synchronized operation between an LCD pixel and an LED chip.

FIG. 7 is yet another diagram illustrating synchronized operation between an LCD pixel and an LED chip. FIG.

8 is a diagram schematically showing the structure of a single-plate projection system of the present invention.

9 is a perspective view of the FS-LCD.

10 is a plan view of the LED array of the FS-LCD.

11 is a view showing a driving method of the FS-LCD.

12 shows synchronized operation between FS-LCD pixels and LED chips.

FIG. 13 is yet another diagram illustrating synchronized operation between an FS-LCD pixel and an LED chip. FIG.

14 is a diagram schematically showing the structure of a two-plate projection system of the present invention.

15 is a view showing a driving scheme of a two-plate projection system.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection system using a light emitting device as a light source, and more particularly, to a light emitting device projection system consuming a very small current and at the same time having a very small and light form.

Conventional projection systems or projectors (hereinafter, projection systems) used in the prior art had to have sufficient brightness to obtain the required screen brightness. Therefore, traditional types of projection systems have used high current consumption lamps such as metal halide lamps, high pressure mercury lamps and xenon lamps to achieve this brightness.

The structure of a conventional projection system using such a lamp is shown in FIG. In FIG. 1, the illustrated projection system includes a white light source lamp 110 incident to an optical system, first and second fly-eye lenses 112 and 114 that improve brightness distribution of light, and light evenly distributed while passing through the fly-eye lens. Polarizing beam splitter (PBS) for polarizing, focusing lenses 118 and 120 for focusing light, total reflection mirrors 122, 124, 126 and 128 for changing the direction of light, dichroic lenses 130 and 132 for transmitting only red and green, respectively, dichroic lens), splitting light focusing lenses (144, 146, 148) for focusing red, green, and blue light, liquid crystal panels (134, 136, 138) for adjusting the transmittance of red, green, and blue in response to video signals from video display devices Dichroic prism 140 for synthesizing red, green, and blue transmitted light transmitted from the light, and projection for emitting the synthetic light from the dichroic prism The lens 142 is included.

Briefly describing the operation of the optical system, the white light emitted from the light source 110 is polarized by the polarization separator 116 and focused by the focusing lens 118 and then totally reflected by the total reflection mirror 122. After the totally reflected light is focused again in the focusing lens 120, the red light passes through the red transmission dichroic lens 130 as it is, and the remaining green and blue light are totally reflected again.

The red light transmitted from the red transmissive dichroic lens 130 is incident on the dichroic prism 140 through the red light control liquid crystal panel 34 which is totally reflected by the total reflection mirror 124 to control the amount of red light transmitted, and the dichroic The remaining rust totally reflected from the lens 130

The color and the blue light pass through the blue light transmitting dichroic lens 132 and the blue light is transmitted and the green light is totally reflected here and is incident on the dichroic prism 140 through the green light control liquid crystal panel 136.

The blue light transmitted from the blue light transmitting dichroic lens 132 is totally reflected by the total reflection mirrors 126 and 128 and is incident on the dichroic prism 140 through the blue transparent liquid crystal panel 138. The red, green, and blue light incident on the dichroic prism 140 are light-synthesized and emitted forward through the projection lens 142. In front of each liquid crystal panel, separate light focusing lenses 144, 146, and 148 for focusing red, green, and blue light, respectively, are provided.

Meanwhile, the blue light, which is finally separated from the blue transparent dichroic lens 132 and has a longer path compared to other red and green light, is incident on the blue transparent dichroic lens 132 and the two total reflection mirrors 126. 128, the light traveling path is compensated by the first relay lens 150 and the second relay lens 152 in between.

Since the structure uses a plurality of dichroic lenses and mirrors for color separation and needs to allocate some optical paths, the entire optical system must have a predetermined volume or more. Therefore, the conventional projection system structure is not suitable as a small projection system structure in which the total volume must be very compact.

In addition, in the above structure, a high current consumption lamp is used as the light source 110 in order to obtain high brightness, and these lamps consume a large amount of current, and thus have a disadvantage in that they become hot at operation and shorten their lifetime. In other words, the structure is not suitable for portable projects that have no choice but to use batteries.

Therefore, in order to realize a projection system having a compact structure or a compact and portable projection system that is expected in the future, a new model in which both the light source of the conventional projection system and the light source system are changed must be developed.

An object of the present invention is to provide a structure of a projection system in which the operation of an LCD panel driver and an LED array driver are synchronized as a three-plate type LCD projection system.

It is another object of the present invention to provide a structure of a single-color color LCD projection system.

Another object of the present invention is to provide a structure of a two-plate color LCD projection system.

Another object of the present invention is to provide a structure of a portable LCD projection system.

Another object of the present invention is to provide a structure of an LCD projection system for a mobile phone.

The structure of the three-panel projection system of the present invention for achieving the above-mentioned object is a red LCD panel, a green LCD panel and a blue LCD which process only respective signals by separating the red component, the green component and the blue component with respect to the image to be displayed. panel; A red light emitting device array, a green light emitting device array, and a blue light emitting device array disposed on a rear surface of each of the red LCD panel, the green LCD panel, and the blue LCD panel, respectively, to emit red, green, and blue light; Optical composite means for receiving the red, green, and blue light emitted from the respective light emitting element arrays through the corresponding LCD panels, receiving all of them, and integrating them to project the image in a projection method; A timer for generating a predetermined clock signal; A light emitting device array driver which senses a pixel currently activated according to a clock signal of the timer and synchronizes it with each other to control the chips of each light emitting device array; It is configured to include; LCD panel driver for controlling each LCD panel.
The LCD panel driver sequentially activates each pixel constituting the LCD panel, and the light emitting element array driver drives the light emitting element closest to the activated pixel of the LCD panel in synchronization with the activation time of the corresponding pixel. Each light emitting device constituting the light emitting device array is sequentially driven in synchronization with the activity of the corresponding pixel of the panel.

Each of the light emitting device arrays may include any one type of optical devices of LED, OLED, LD, EL, and FED. In addition, the optical complex means may comprise a dichroic prism and lens means. In addition, the clock signal may be a signal for activating a scan line for a pixel of each LCD panel. In addition, the synchronization may be such that the light emitting element corresponding to each pixel to be activated when the pixels of each LCD panel are sequentially activated is activated at substantially the same moment.

In addition, the light emitting device corresponding to any pixel of each LCD panel is at least one of the light emitting devices having the closest distance from the pixel and / or adjacent light emitting devices having the closest distance from the light emitting device. Can be.

The synchronization may be when the clock signal starts activating a particular scan line of the LCD panel together to activate the rows of the light emitting element array closest to the scan line together. Alternatively, the synchronization starts activating a row of the light emitting element array closest to the corresponding scan line when the clock signal starts activating a specific scan line of the LCD panel, and emits the light when the activation of the scan line is completed. Activation of the device array row may also be completed.

And a synchronization unit positioned between a timer and the light emitting element array driver in the structure and correcting a delay or distortion of the clock signal when the clock signal generated from the timer is provided to the light emitting element array driver. Can be. The synchronization unit may include clock signal capturing means for recognizing the clock signal and a second timer for correcting the captured clock signal to generate a second clock signal.

A single-plate projection system of the present invention for achieving the above object comprises: an LCD panel for processing an image signal to be displayed; An array of light emitting elements disposed on a rear surface of the LCD panel and capable of emitting red, green, and blue light; Lens means for reproducing red, green, and blue light emitted from the light emitting element array when the light passes through the LCD panel in a projection method; An LCD panel driver for controlling the LCD panel; A light emitting device array driver for controlling the light emitting device array; The LCD panel driver and the light emitting device array driver are operated in synchronization with each other. The LCD panel displays a color of an afterimage to a corresponding pixel by passing or shielding only a specific light with respect to a predetermined pixel among R, G, and B lights sequentially emitted from the light emitting device array without a color filter. It may be to configure the LCD.

The light emitting device array may display image information of the pixel using one red light emitting device, two green light emitting devices, and one blue light emitting device as a group. The light emitting device group may be a light emitting device group having a closest distance from the pixel.

The light emitting device group may include at least one of the light emitting device group having the closest distance from the pixel and the adjacent light emitting device group having the closest distance from the light emitting device group. In addition, a synchronization unit positioned between the LCD panel driver and the light emitting element array driver, and configured to correct a delay or distortion of the clock signal when a clock signal generated from the LCD panel driver is provided to the light emitting element array driver. It can be included as. The synchronization unit may include clock signal capturing means for recognizing the clock signal and a timer for correcting the captured clock signal to generate a second clock signal. In addition, the light emitting device array may include any one type of optical devices of LED, OLED, LD, EL, and FED.

A two-plate projection system of the present invention for achieving the above object comprises: a first LCD panel for processing a signal relating to a first color group consisting of two color components of a red component, a green component, and a blue component for an image to be displayed; A second LCD panel which processes a signal relating to a second color group composed of the other color component; A first light emitting device array and a second light emitting device array disposed on a rear surface of each of the first LCD panel and the second LCD panel and emitting light of a corresponding first color group and a second color group, respectively; When the light of the first color group and the second color group emitted from each of the light emitting element arrays passes through corresponding LCD panels, one group of light is reflected and the other group of light passes through the projection method. Photocompositing means; A timer for generating a clock signal for controlling the operation of each LCD panel; A light emitting device array driver which receives a clock signal generated from the timer and senses a pixel currently activated and controls the chips of the respective light emitting device arrays by synchronizing thereto; An LCD panel driver for controlling each LCD panel; It may be to include. The light combining means may include a dichroic mirror and a projection lens. Further, the first color group may be red and blue, the second color group may be green, or the first color group may be red and green, the second color group, or the first color group may be green and blue, and the second color group may be red. have.

In addition, the first LCD panel and the first light emitting device array corresponding to the first color group may be an FS-LCD system and the second color group may be formed of green.

The projection system of the present invention may be a portable projector or a projector for a mobile phone which is powered from a mobile phone and projects a mobile phone screen.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1 3-Plate Projection System

2 is a schematic structural diagram of a three-plate projection system using a light emitting element as a light source, that is, a high brightness LED.

In the three-plate projection system of FIG. 2, the configuration of the red, green, and blue LCD panels 134, 136, and 138, and the dichroic prism 140, respectively, is the same as the conventional structure, but instead of a white light lamp as a light source. It is configured to use a red LED array 210, a green LED array 212 and a blue LED array 214 disposed in close proximity to each of the LCD panels.

The operation of the above structure is that each of the LED arrays 210, 212, 214 emits light having respective wavelength bands, and the emitted light passes through corresponding LCD panels, depending on the color information of the screen to be displayed. The amount of emitted light is adjusted, and all are synthesized in the dichroic prism 140 and sprayed onto the screen through the front projection lens 142.

In the embodiment of Figure 2 it can be seen at a glance that the volume of the entire projection system is very compact and compact by eliminating the need for optical systems and thus the space required in the conventional structure. Therefore, a projection system having a small volume, which is one of the objects sought in the present invention, can be achieved with this configuration.

Further, in the above embodiment, each LCD panel is controlled by screen driving, frame conversion, etc. by the LCD driver, and at the same time, the LED array is controlled by the LED driver. The LCD driving unit and the LED driving unit are connected to the synchronizing unit so that the blinking of the LED driving unit is synchronized according to the pulse signal of the LCD driving unit. Synchronization in the present invention simply means that when the pixels of each LCD panel are activated at a particular moment, the light emitting element corresponding to each pixel to be activated is activated at substantially the same moment.

In this case, the light emitting device corresponding to the position means at least one of light emitting devices having the closest distance from the corresponding pixel and / or adjacent light emitting devices having the closest distance from the light emitting devices. In the following, other embodiments are the same.

The reason for this synchronized operation is as follows.

Each of the LED arrays is a high density integrated unit chips of a high power light emitting device, for example, in order to obtain the required brightness, at least 20 × 15 chips may be in a two-dimensional form in which they are mounted in parallel.

When so many LED chips operate continuously on at a time, if a driving current of about 10 mA / h is required per chip, a current having a density of at least 3 A / h or more for each LED array is required. All of the light emitting device arrays must be supplied with a high density of current of about 9 A / h or more.

Since a typical lithium-ion battery for a mobile phone has a maximum output of about 300 mAh, the output current of 9 A / h is a very large amount of current. Therefore, the projection system is operated with three LED arrays turned on continuously as described above. If you have to use it, it's hard to get a projection system running for more than a few minutes with your current battery capacity.

Therefore, in the present invention, in order to enable the projection system to be used for a relatively long time even when using a battery or very low power, each individual chip of the LED array is turned on / off even when the projection system is turned on. It was configured to operate repeatedly and pulsed. In addition, the chips belonging to one LED array are sequentially turned on and off according to the order in which the LEDs are arranged, and the LED chips to be turned on are LED chips corresponding to positions of LCD cells into which image signal data of the LCD screen is input. It is configured to be.

3 is a block diagram illustrating an embodiment of a synchronization unit in the structure of FIG. 2. In Fig. 3, the LCD driving unit for controlling the three LCD panels includes at least an LCD control unit for controlling the entire driving unit, and a timer 1 for generating a clock signal necessary to operate the control unit in a pulse form.

In addition, the timer 1 is connected to a synchronization unit including a synchronization signal capturing means and a timer 2 for generating a clock signal required to operate the LED driver, and the synchronization unit is connected to the LED array controller of the LED driver.

For reference, the synchronizer is a block that may be included in the LED driver or the LCD driver.

The following describes how the structure works.

First, the operation of the LCD panel will be described with reference to the LCD panel structure shown in FIG. 4.

The structure of FIG. 4 is for an AM LCD (Active Matrix LCD), wherein each pixel electrode 401 has scanning lines 402 (1) to 402 (m) together with thin film transistors 406 controlling them. And data lines 403 (1) to 403 (n), each of which is controlled by a scan driver IC and a data driver IC, and the LCD panel of FIG. (row) x Total number of pixels or points, which is the number of columns.

The gate electrodes of the TFTs arranged on the same scanning line are all connected to the corresponding scanning line, and the drain electrodes of the TFTs arranged on the same data line are connected to the corresponding data line. The source electrode of each TFT is connected to the corresponding pixel electrode.

In operation, once the image data to be currently displayed is provided, the scan driver IC then scans all of the scanning lines 402 (1) to 402 (m) and inputs an H signal to one or more of them to turn on. Let's do it.

On the other hand, when the data driver IC supplies the image data to the data lines 403 (1) to 403 (n), the TFTs turned on in the scanning line pass the image data to pass through the corresponding pixel electrode 406. Image data is displayed. In this way, once all of the scanning lines are scanned sequentially, the display for one frame is complete.

In a practical situation, when the pulse wave provided from the timer 1 gives a clock signal, that is, an H or L signal to the scanning line, the pulse wave provided by the timer 1 is sequentially turned on from the left TFT to the right TFT closest to the scan driver IC. The display will be a way of scanning the scanning lines from left to right, as in the conventional CRT scanning lines, and then again performing the same operation on the lower scanning lines to complete the entire frame.

Timer 1 of FIG. 3 is made of a crystal oscillator or the like, and generates an H (hign) or L (low) pulse wave as a clock signal and provides it to the LCD control unit. The clock signal provided to the LCD control unit is an LCD panel as described above. It is used to sequentially turn on each pixel of.

In this situation where the timer 1 provides the clock signal to operate the LCD modules, the clock signals are provided together with the scan driver IC as well as the synchronization signal capturing means of the synchronization unit connected via the synchronization bus line.

The synchronization signal capturing unit receives the clock signal and recognizes the clock of the timer 1 by measuring the time at which the edge of the H or L signal of the signal occurs, and then provides it to the timer 2 to supply the timer 2 to the timer 2. Causes a new clock signal to be generated in synchronization with the signal of Timer1. This new clock signal is provided to the LED driver.

When the clock signal is provided to the LED driver, the LED driver uses the signal to control the blinking of the LED array in synchronization with the LCD driver.

Synchronization here does not simply mean that the LCD panel and the LED array are turned on in the same time zone in time, but as described above, the chips of the LED array, ie, the most near-field, corresponding to the pixels of the LCD turned on sequentially. It means that only me or the peripheral chips are synchronized to be turned on at the same time.

FIG. 5 schematically shows the flashing state of each pixel of the LCD panel and LED array chips controlled in synchronization thereto.

The left side of Fig. 5 shows a typical LCD panel composed of all 10 x 10 pixels, with small squares representing one pixel. In addition, the right side shows an LED array composed of all 5 × 5 LED chips, and the square inside shows one LED chip.

As shown in FIG. 2, each LED array is disposed directly behind each LCD panel or corresponding to the shortest distance, so that light from the LED array is used as a backlight of the LCD panel. Thus, one LED chip 510 corresponds to about four pixels 512. For reference, the 1: 4 correspondence is merely illustrative for the purpose of illustration, and in fact, may correspond to a different number or form.

The synchronization of the present invention described in FIG. 6 is based on the position of the chip of the LED array, i.e., the shortest distance, when each pixel is sequentially turned on from the upper left to the lower right to make the LCD panel display a frame. The chip located or the chip around it is turned on. That is, when the illustrated pixel 610 is turned on, only the LED chip 612 corresponding to the position emits light, and when the pixel is turned on outside the position, the LED chip is turned off and the next position instead. The LED chip placed on the board is turned on to operate.

In this way, if the LED chips are turned on / off sequentially, all the LED chips can be used as a backlight even if all the LED chips do not continuously emit at the same time, and at the same time, it can save more power than the conventional method.

In the above method, the LED driver recognizes which LCD pixel is currently turned on. For example, a scan line of one of the LCD panels is turned on every time a clock signal of Timer1 occurs. The LED driver detects which clock signal the current clock signal is in the current frame, and then sequentially turns on the LED chips of the corresponding row. In addition, all LED chips in a row are turned on sequentially by the same time, and if the turn-on time is set equal to the scanning period of one scan line of the LCD panel, the LCD pixel and LED of one row are set. The turns on of chips are automatically synchronized.

In summary, when the clock signal starts activating a specific scan line of the LCD panel, that is, turning on, the step of activating a row of the light emitting element array closest to the corresponding scan line together, i.e., turning on, starts the scan line. The synchronization operation is performed in such a manner that the activation of the row of the light emitting element array is completed when the activation of the.

FIG. 7A illustrates another embodiment of the present invention in which a corresponding chip and some of its peripheral chips 712 are turned on at the same time when one LCD pixel 710 is turned on.

If the corresponding LED chip 712 and its peripheral chips 714 are both turned on when a particular pixel 710 is turned on, a brighter backlight, even though it consumes more power than the embodiment of FIG. Has the advantage that it is made.

In order to appropriately reduce the power consumption, for example, as shown in FIG. 7B, only a part of the center chip and its peripheral chips may be configured to be turned on.

In another similar method, both the central chip and the peripheral part may be turned on, but the amount of power supplied to the peripheral chip may be smaller than the amount of power supplied to the central chip, thereby reducing the power consumption and obtaining backlight brightness having similar intensity.

As described above, the embodiment of the three-panel projection system of the present invention uses the phenomenon in which the pixels of the LCD panel are sequentially turned on to synchronize the power consumption by synchronizing only the LED chip disposed at the position corresponding to each pixel to be turned on at that moment. Reduction is the main technical idea. In addition, the power consumption is reduced, and the LED operates in a pulsed manner, which can radiate heat at turn-off, thereby improving the heat dissipation characteristics of the chip and the array and extending its lifespan. In addition, since the chip is not easily degraded, it is also possible to supply a larger current than the conventional one for improving luminance.

Example 2: Single-Phase Projection System

FIG. 8 illustrates another embodiment of the present invention, and this time configures an optical system of a single-panel projection system consisting of only one LCD panel and one LED array corresponding thereto.

In this case, unlike the three-plate system described above, not only does one LCD panel 810 and one LED array 812 be used, but also the size of the projection system is further increased because no dichroic prism for color mixing is required. The advantage is that it can be reduced. The illustrated synchronization unit and the like are the same as or similar to the first embodiment, so detailed description thereof will be omitted.

FIG. 9 illustrates a system in which the single-plate projection system of FIG. 8 is manufactured by, for example, a field sequential LCD (FS-LCD) method.

FS-LCD refers to a display system in which an LCD panel displays colors using an afterimage by selectively passing or shielding LED chip light at the bottom.

Conventional color LCD panels have three subpixels representing R (Red), G (green), and B (Blue) to form one pixel, and each subpixel has R, G, and B color filters. The above-described FS LCD is characterized in that it is configured to display various lights without subpixel and color filter parts.

9 and 10 schematically show a perspective view of a FS LCD and a plan view of an LED array, which is a part of the configuration thereof. Here, as an example, one R chip, two G chips, and one B chip are used as one example. The R, G, and B chips are organized in a matrix to form a group.

In FIG. 9, when the lower LED chips emit light, the LED chips pass through the polarizer and are configured to be blocked or passed by the LCD panel, and the LED chips have a complex configuration of R, G, and B.

11 is a view showing the operation of the FS LCD, the horizontal axis shows the passage of time.

The chips in the LED array repeat high-speed flashes in the order of, for example, R, G, B, R, G, B, ... and in synchronization with this, the LCD panel passes or blocks the light emitted by the underlying LED chips. . Thus, for example, when one pixel is to display red color, the blinking of the chip group corresponding to the position of the pixel is first transmitted when the R chip of the LED array is turned on and the corresponding pixel of the LCD panel is in a transmissive state. Next, in the turn-on state of the G and B chips, the light shielding state is performed. Only at least R light shines through the pixel.

In addition, when a pixel is to be displayed in yellow, in the chip group of the LED array corresponding to the pixel, when the R and G chips are sequentially turned on, the corresponding pixel of the LCD panel is transmitted and then the B chip is turned on. When it is on, I make it shading. Then, after the R and G light are mixed by the afterimage effect occurring in the human eye, it is recognized that yellow light is reflected from the pixel.

It is also possible to display more complex halftone colors by controlling the transmittance or time ratio of the LCD panel within each color period.

 When the FS LCD having such a structure is used in the single-plate projection system of FIG. 8 of the present invention, since the aperture ratio is large and there is no light loss due to the color filter, the projection having relatively bright backlight is used even when using an LED chip having the same brightness as before. You can configure the system. It is also possible to construct a low power consumption projection system, since bright backlights can be obtained even with relatively moderate brightness LEDs.

Another advantage of the color filter elimination in the single-plate projection system of the present invention is that the number of manufacturing processes is reduced and the number of data drivers is reduced to one third at the same resolution as in the prior art, thereby making it possible to make a low-cost projection system.

For reference, the chip arrangement structure of the above-described LCD panel or LED array is just one embodiment, and it will be readily understood by those skilled in the art that arrangement of pixels or chips in various other similar structures is possible.

FIG. 12 is a diagram schematically illustrating an operation of a corresponding LED array chip when pixels are sequentially turned on in the above structure.

First, in FIG. 12A, when a specific pixel 1210 is turned on during display frame formation, for example, a red (R) expression is to be displayed, a position of the LED corresponding to the pixel 1210 of the LCD being turned on The chip group 1220 is turned on but the pixel is made transparent only when the red chip 1230 corresponding to the color is turned on as described above.

In this manner, when the turn-on is controlled for each chip group and the image processing for the pixels corresponding to the chip group is finished, the next chip group 1250 again displays the image in the same manner as shown in FIG. 12B. Next, the chip group 1250 illustrates a case in which blue B is displayed for the pixel 1240.

Unlike FIG. 12 described above, FIG. 13 illustrates a case in which an image display for a specific pixel serves as a backlight not only for the nearest chip group but also the peripheral chip group. That is, when red (R) is to be displayed on the pixel 1310, not only the nearest chip group 1320 but also the surrounding chip group 1330 are shown to emit red light at this time. In this configuration, the brightness of the backlight may be improved to form a brighter projection screen.

Example 3: Two-Plate Projection System

Since the FS-LCD of the single-panel projection system described above does not have a color filter, the LEDs for each wavelength should be synchronized and turned on for R, G, and B image signals. Therefore, if one frame is completed at 60 Hz, the R, G, and B LED chips, which are backlights, must be turned on and off within one-third of the time occupied by each pixel. It should work, and the shutter action of the LCD panel should be synchronized with it.

Currently developed LED chips can exhibit such high-speed response characteristics, but LCD panels are still unstable at such high-speed operation except for recently mentioned ferroelectric liquid crystal (SSFLCD).

The present invention, as a countermeasure, provides a configuration of a projection system using a two-panel LCD composed of two LCD panels.

FIG. 14 is a structural diagram schematically showing an example of such a two-panel projection system, in which one LCD panel 1410 corresponding to one color and one LCD panel 1420 corresponding to two colors are passed through the same. An optical system, such as a double dichroic mirror 1430, in which one light is mixed and incident on a projection lens, is configured.

In the above structure, for example, an LCD panel corresponding to one color may be configured to process a green video signal and the other panel may process a red and blue video signal, in which case both LCD panels operate at 120 Hz. Or if one LCD panel is operating at 60Hz and another LCD is only 120HZ, there is no problem dealing with 60Hz screen frame.

For example, FIG. 15 schematically shows on / off of the first LCD panel corresponding to green and the second LCD panel corresponding to red / blue to display yellow and blue, respectively, and the shaded portion indicates the shading state. It is shown and the scale in the horizontal axis direction is time corresponding to 120 Hz.

Therefore, to display yellow, the second LCD panel only needs to be in the transmissive state for a time corresponding to the initial 120 Hz, which is the turn-on period of the red LED, while the first LCD panel is in the transmissive state for 60 Hz. . In addition, when it is desired to display blue, the second LCD panel only needs to be in a transmissive state in the second half while the first LCD panel is always in a light shielding state.

In the above embodiment, when the first LCD panel operates at the same 120 Hz as the second LCD panel, the first LCD panel may be split in two time units and may operate in 120 Hz units, respectively.

Another advantage of the embodiment of FIG. 15 is that the turn-on time of the first LCD panel is three times longer and the turn-on time of each color of the second LCD panel is 1.5 times longer than that of the single plate type. This can increase the brightness of the backlight.

In addition, in particular, when the first LCD panel having a longer wavelength as shown in FIG. 15 processes only a green image signal, the flashing time of green, which is weaker than that of red and blue, can be doubled compared to other colors. Another advantage is that you do not have to increase the number of green LED chips in the LED array. However, the combination of processing a blue or red signal with the 60 Hz driving first LCD panel and processing a red / green or green / blue signal with the 120 Hz driving second LCD panel is also possible.

The two-plate structure has advantages in that a conventional liquid crystal panel can be used as it is, and two LED arrays can be used to obtain higher luminance because the density or number of LED chips to be mounted is increased compared to a single-plate projection system. In addition, compared to the three-panel projection system, since only two LCD panels are used and a low-cost dichroic mirror is used instead of the prism, the manufacturing cost can be drastically reduced and the size of the product can be drastically reduced. Have

In the above-described embodiments of the present invention, the synchronization unit including the synchronization signal capturing unit and the timer 2 may be configured to perform signal attenuation, distortion, or latch of the clock signal of the timer 1, which is actually made of only a simple bus line or is a high frequency signal. It may also consist of only a compensation circuit. This is because there is no problem in synchronizing as long as the pulse clock signal of timer 1 is provided to the LED driver as it is without distortion.

In addition, although the FS-LCD has been described as an important example in the single-plate or two-plate projection system among the above-described embodiments, the LCD panel of another structure without the color filter or the LCD panel having extremely low light blocking rate even with the color filter is described. Can be used instead of FS-LCD.

The present invention relates to a projection system of the present invention, which uses a LED array as a light source and a projection system in which the overall size is small and the power consumption is dramatically reduced.

In particular, the three-plate projection system of the present invention using three pairs of LED arrays and an LCD panel is much smaller in size than a conventional lamp-type projection system and at the same time uses chips of the LED array to correspond to the pixels being scanned on the LCD panel. By blinking in a pulsed form, the power consumption is drastically reduced compared to a conventional lamp or a conventional LED which should always be turned on.

In addition, the single-plate projection system of the present invention has a structure in which the size and power consumption are further reduced by eliminating the dichroic prism.

In addition, although the two-panel projection system of the present invention includes a dichroic mirror and the like, the size and power consumption are larger than those of the single-plate type, but instead, the structure may be more stable and the screen brightness may be further improved. have.

Therefore, since the projection system of the present invention can be configured in a compact and low power type, it can be made portable using a battery as described above. In addition, the projection system of the present invention may be configured as a projection system for a mobile phone that is modularly attached to the mobile phone and projects the screen information of the mobile phone onto a wall while receiving power from the battery of the mobile phone.

Those skilled in the art having an understanding of the structure of the projection system of the present invention will be able to easily think of various modifications in addition to the above embodiments. For example, in addition to the LED as a light source, any light source that can be made in a flat form such as an organic light emitting device (OLED), a laser diode (LD), an EL device (Electroluminescence device), a field emission display (FED), etc. to be.

Therefore, what is expressed as a light emitting device array in the claims of the present invention should be understood as a concept that includes all of these, and furthermore, the present invention should not be construed as limited to the above embodiments.

Claims (28)

LCD panel; A light emitting device array comprising a plurality of red, green, and blue light emitting devices arranged in an array and disposed on a rear surface of the LCD panel; Light-combining means for receiving all of the red, green, and blue light emitted from the light emitting element array and passing through the LCD panel, integrating and projecting a predetermined image in a projection method; A timer for generating a predetermined clock signal; An LCD panel driver configured to control driving of the LCD panel according to a clock signal provided from the timer; A light emitting element array driver for controlling driving of the light emitting elements of the light emitting element array; Including, The LCD panel driver sequentially activates each pixel constituting the LCD panel, The light emitting device array driver divides the light emitting device array into a plurality of areas to form a plurality of light emitting device groups including at least one light emitting device included in each of the divided areas, and closest to the activated pixels of the LCD panel. By driving the light emitting elements of the light emitting element group in synchronization with the activation time of the corresponding pixel, each light emitting element group constituting the light emitting element array is sequentially driven in synchronization with the activation of the corresponding pixel of the LCD panel. system. The projection system of claim 1, wherein each array of light emitting devices comprises one of light emitting devices of any one of LED, OLED, LD, EL, and FED. A projection system according to claim 1, wherein the light combining means comprises a dichroic prism and lens means. delete delete delete The LCD device of claim 1, wherein the clock signal is a signal for activating scan lines for pixels of the LCD panel, and the LCD panel driver sequentially activates scan lines of the LCD panel according to the clock signal. The light emitting device array driver forms light emitting device groups including light emitting devices constituting one row of the light emitting device array, and sets the light emitting device group closest to the activated scan line of the LCD panel to the activation time of the corresponding scan line. And by synchronizing driving, sequentially driving the light emitting element groups constituting the light emitting element array in synchronization with the activation of the scan line of the LCD panel. delete The LCD panel of claim 1, wherein the LCD panel comprises a red LCD panel, a green LCD panel, and a blue LCD panel. The light emitting device array may include a red light emitting device array, a green light emitting device array, and a blue light emitting device array, and the red light emitting device array may be disposed on a rear surface of the red LCD panel, and the green light emitting device array may be formed of the green LCD panel. And a blue light emitting element array disposed on a rear surface of the blue LCD panel. 2. The apparatus of claim 1, further comprising: a synchronization unit positioned between the timer and the light emitting element array driver and correcting a delay or distortion of the clock signal when the clock signal generated from the timer is provided to the light emitting element array driver; Projection system, characterized in that it further comprises. 11. The projection system of claim 10, wherein the synchronization unit comprises clock signal capturing means for recognizing the clock signal and a second timer for correcting the captured clock signal to generate a second clock signal. delete The LCD panel of claim 1, wherein the LCD panel passes or shields only a specific light with respect to a predetermined pixel among R, G, and B lights sequentially emitted from the light emitting element array without a color filter, thereby preventing color of an afterimage. Projection system, characterized in that to configure the FS LCD to be displayed on the pixel. The projection system according to claim 13, wherein each group of light emitting elements comprises one red light emitting element, two green light emitting elements, and one blue light emitting element. delete delete delete delete delete A first LCD panel which processes a signal relating to a first color group consisting of two color components of a red component, a green component, and a blue component for an image to be displayed, and a signal relating to a second color group composed of the other color component. A second LCD panel; A first light emitting device array in which light emitting devices emitting a first color group are arranged in an array and disposed on a rear surface of the first LCD panel; A second light emitting device array configured to have light emitting devices emitting a second color group in an array form and disposed on a rear surface of the second LCD panel; Light-combining means for emitting light from each of the light emitting element arrays, reflecting light of one group of the light passing through the LCD panel, and passing the light of the other group to project in a projection method; A timer for generating a predetermined clock signal; An LCD panel driver which controls an operation of each LCD panel according to the clock signal of the timer; A light emitting device array driver which senses a pixel currently activated according to a clock signal of the timer and synchronizes it with each other to control the chips of each light emitting device array; Projection system comprising a. 21. A projection system according to claim 20, wherein the light combining means comprises a dichroic mirror and a projection lens. 21. The projection system of claim 20, wherein the first color group is red and blue, and the second color group is green. 21. The projection system of claim 20, wherein the first color group is red and green, and the second color group is blue. 21. The projection system of claim 20, wherein the first color group is green and blue, and the second color group is red. 21. The projection system of claim 20, wherein the first LCD panel and the first light emitting element array corresponding to the first color group are FS-LCD systems. 26. The projection system of claim 25, wherein said second color group is green. 27. The apparatus of any of claims 1-3, 7, 10, 11, 13-14, 20-20, wherein the projection system is a portable projector. Characterized in a projection system. 27. The projection system of any one of claims 1 to 3, 7, 10, 11, 13, 14, 20, and 26, wherein the projection system is configured to power off a mobile phone. Projection system characterized in that the projector for the mobile phone supplied and projecting the mobile phone screen.

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