KR19980085794A - Deformable mirror device projector and projection method using the same - Google Patents

Abstract

Disclosed are a projector capable of implementing a color display using a single plate deformable mirror device (DMD) and a projection method using the same. The projector includes a light source for generating light rays, a projection lens for projecting an image on a screen, a DMD module disposed between the light source and the projection lens, and red, green, and blue disposed between the DMD module and the projection lens. It includes a color filter of. The DMD module has an array of reflective pixels that can pivot about axis and reflect the incident light beams inward or outward of the projection lens in response to an applied image signal. Three actuators are formed in one pixel corresponding to red, green, and blue color light rays, and each actuator is deformed at a different tilting angle. Therefore, it is possible to implement a high luminance color display with only one DMD module without light loss.

Description

Deformable Mirror Device Projector and Projection Method Using The Same

The present invention relates to an optical projection system using a projector using a single panel deformable mirror device (DMD) and a projection method using the same. More specifically, the present invention is a DMD projector and a projection method using the same to form a high luminance color display by forming three actuators corresponding to the red, green and blue color image in one pixel of the DMD module It is about.

In general, spatial light modulators, which are devices for projecting optical energy onto a screen, can be applied to various fields such as optical communication, image processing, and information display devices. Typically, such devices are classified into a direct-view image display device and a projection-type image display device according to a method of displaying optical energy on a screen.

An example of a direct-view image display device is a CRT (Cathode Ray Tube). The CRT device is called a CRT, which has excellent image quality but increases in weight and volume as the screen is enlarged, leading to an increase in manufacturing cost. There is.

Projection type image display apparatuses include a liquid crystal display (LCD), a deformable mirror device (DMD), and an actuated mirror array (AMA). Such projection image display devices can be further divided into two groups according to their optical characteristics. That is, devices such as LCDs can be classified as transmissive spatial light modulators, while DMD and AMA can be classified as reflective spatial light modulators.

Transmission optical modulators, such as LCDs, have a very simple optical structure, which makes them thinner, lighter in weight, and smaller in volume. However, due to the polarity of the light, the light efficiency is low, there is a problem inherent in the liquid crystal material, for example, there is a disadvantage that the response speed is slow and the inside is easy to overheat. In addition, the maximum light efficiency of existing transmission light modulators is limited to a range of 1-2%, requiring dark room conditions to provide acceptable display quality.

Optical modulators such as DMD and AMA have been developed to solve the problems of the aforementioned LCD type optical modulators.

DMD is a light modulator mainly used in a digital type reflective projector, and FIG. 1 corresponds to the colored lights by sequentially projecting red, green, and blue light rays onto a screen using a single-plate DMD. A conventional DMD projector capable of displaying color images is shown.

In order to display a color image on the screen, three rays of red, green and blue must be modulated by a spatial light modulator, such as a DMD module, especially in projection systems using single-plate light modulators. There is a need for means for irradiating green and blue lights.

Referring to FIG. 1, a conventional single plate type DMD projector 10 includes a 170W to 250W metal halide lamp 11 for emitting light, and a light source for condensing the light emitted from the lamp 11. A condenser lens 14, a color wheel 13, a condenser lens 14 for converting the color light beams obtained by the color wheel 13 into parallel light, and a color light beam passing through the condenser lens 14 Projecting light reflected from the DMD module 18 on the mirror 32, the DMD module 18 having an array of reflective pixels 22, and a primary beam to change the optical path of And a projection lens 30 for. The reflector 15 serves to reflect the light rays emitted from the lamp 11 in the opposite direction with respect to the focusing lens 12 and back to the focusing lens 12.

2 is an enlarged view of the color wheel 13. The color wheel 13 consists of a series of color segments of red, green and blue transmission filters and changes the color of the white light while rotating about its axis by means of a drive such as a motor.

The operation principle of the conventional single-plate type DMD projector 10 having the above structure will be briefly described as follows.

First, when driving the DMD projector 10, the light rays emitted from the halogen metal lamp 11 are focused toward the color wheel 13 by the focusing lens 12. The color wheel 13 rotates about its axis such that its color segments sequentially block white light. Accordingly, after the white light passes through the color wheel 13, it sequentially changes into red, green, and blue color light rays, which are converted into parallel light by the condenser lens 14 to the source mirror 16. The light is irradiated and the light path is primarily changed, and then sequentially irradiated to the DMD module 18.

3 is a plan view of the DMD module 18, where each reflective pixel 22 can pivot about a torsion hinge 24 located at two diagonal corners of each pixel 22 (see FIG. pivotable). When an appropriate ON voltage is applied to the pixel 22, the upper left corner 26 of the pixel 22 moves upward from the plane of the DMD module 18, while the lower right corner 28 moves downward. Similarly, when an OFF voltage is applied, the pixel pivots about the torsion hinge 24 such that the upper left corner 26 moves downward and the lower right corner 28 moves upward. Thus, the ON position and the OF position consist of two different movements of each pixel 22.

In the OFF position, incident color light rays are reflected out of the aperture of the projection lens 30 and do not reach the screen 32. In contrast, in the ON position, the incident color light rays are reflected into the aperture of the projection lens 30 and projected onto the screen 32 by the projection lens 30 to display a color image corresponding thereto. For example, when red light is irradiated onto the DMD module 18, the DMD module 20 forms an image corresponding to red and projects it on the screen 32. Then, the green image by the green light ray and the blue image by the blue light ray are sequentially displayed on the screen 32. However, with the naked eye, the monochrome images of each of the red, green, and blue colors are combined and recognized as full color.

According to the conventional single-plate DMD projector described above, the white light is sequentially changed into red, green, and blue light using a color wheel. The color wheel is rotated about its axis so that three color segments (i.e. red, green and blue segments) each occupying one third of the area are sequentially blocked white light, so that the total white light emitted from the lamp 2/3 of it is always lost. In addition, when white light is irradiated to the boundary regions of the color fragments of the color wheel, there is a problem in that the contrast is lowered because the light rays of the color that are spread out do not come out of the single color.

Accordingly, the present invention has been made to solve the above-mentioned conventional problem, and an object of the present invention is to provide a red, green and blue color image in one pixel of a DMD module in a projector using a single-plate DMD module. An object of the present invention is to provide an optical projection system capable of forming a high-luminance color display by forming three corresponding actuators.

Another object of the present invention is to provide a projection method capable of realizing a color display of high luminance using the DMD projector.

1 is a schematic diagram showing a single-plate deformable mirror device projector according to a conventional method.

FIG. 2 is an enlarged view of the color wheel shown in FIG. 1.

3 is a plan view of the deformable mirror device module illustrated in FIG. 1.

4 is a schematic view showing a single plate deformable mirror device projector according to the present invention.

FIG. 5 is a plan view of the deformable mirror device module illustrated in FIG. 4.

6 is a plan view illustrating one pixel of a deformable mirror device module according to an exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view of the pixel illustrated in FIG. 6.

8 is a cross-sectional view illustrating one pixel of a deformable mirror device module according to another exemplary embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

100: DMD projector 111: lamp

112: source lens 114: source mirror

115: reflector 118: DMD module

120a, 120b, 120c: Color Filter

130: projection lens 132: screen

In order to achieve the above object of the present invention, the present invention provides a light source for generating light rays; A projection lens for projecting an image onto the screen; Disposed between the light source and the projection lens, having an array of reflective pixels that can pivot about an axis and reflect incident light rays in or out of the projection lens according to an applied image signal and modulate the light rays; Three actuators corresponding to the red, green, and blue color light rays, each of which is deformed at different tilting angles; And red, green, and blue color filters disposed between the DMD module and the projection lens.

In addition, to achieve the above object another object of the present invention is to generate a light beam from the light source; Irradiating a light beam generated from the light source to a DMD module having an array of reflective pixels that can be pivoted about an axis, and having three actuators in one pixel corresponding to red, green, and blue color light beams; Deforming the red, green and blue actuators of the DMD module with different tilting angles; Dividing the rays into red, green and blue color rays by irradiating the red, green and blue color filters with the rays reflected from the DMD module modified at different tilting angles; And projecting each of the color light beams onto a screen through a projection lens.

According to the present invention, three actuators (i.e., torsion hinges) corresponding to red, green and blue color light rays are formed in one pixel of a DMD module having an array of reflective pixels that can pivot in axis, and the DMD module Install three color filters between and the projection lens. Each color ray passing through the red, green, and blue filters is projected onto a screen through a projection lens to display a color image.

For example, light rays reflected from an R-actuator with a tilt angle of θ _R are irradiated to the red filter, light rays reflected from a G-actuator with a tilt angle of θ _G are directed to a green filter, and a tilt angle of θ _B. The light reflected from the B-actuator having a is irradiated to the blue filter. The actuators corresponding to the red, green, and blue color light rays may have different tilting angles by differently installing positions of the tilting central axes or differently setting the heights of the landing posts.

Therefore, it is possible to implement a high luminance color display with only one DMD module without light loss.

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

4 is a schematic view showing a single plate type DMD projector according to the present invention.

Referring to FIG. 4, the single plate type DMD projector 100 according to the present invention includes a light source 111, a source lens 112, a source mirror 114, a reflector 115, a DMD module 118, and 3. Color filters 120a, 120b, 120c, projection lens 130, and screen 132.

The light source 111 preferably emits long wavelength infrared (LWIR) to ultraviolet (UV) light in the spectrum as a halogen metal lamp of 170W to 250W. The reflector 115 serves to reflect the light emitted from the lamp 111 in the opposite direction with respect to the source lens 112 to be directed back to the source lens 112.

The source lens 112 collects light rays emitted from the lamp 111 into parallel light. The source mirror 114 reflects the light rays passing through the source lens 112 and changes its path to the DMD module 118.

5 is a plan view of the deformable mirror device module illustrated in FIG. 4, and FIG. 6 is a plan view showing one pixel of the deformable mirror device module according to an exemplary embodiment of the present invention.

The DMD module 118 has an array of reflective pixels 118a that can pivot in axis, as shown in FIG. As shown in Fig. 6, each pixel 118a is mounted so as to pivot about a torsion hinge 124 located at two diagonal corners of each pixel 118a. In the ON position, the edge of the pixel 118a is in contact with the landing post 125 and the pixel 118a is moved to the ON position by applying an appropriate voltage to a control electrode (not shown). Thus, the pixel 118a is modified to reflect the incident color light rays into the aperture of the projection lens 130. On the other hand, in the OFF position, since the pixel 118a moves in the opposite direction, the incident color light rays are reflected out of the aperture of the projection lens 130 so that they do not reach the screen 132. Thus, the ON position and the OFF position consist of two different movements of each pixel 118a.

At this time, one pixel 118a of the DMD module 118 is provided with an R-actuator 119a, a G-actuator 119b, and a B-actuator 119c corresponding to the red, green, and blue color light rays. .

According to one embodiment of the present invention, as shown in Figs. 6 and 7, the R-actuator 119a, the G-actuator 119b and the B-actuator 119c are located at the position of the tilting central axis, that is, the torsion hinge ( 124 is provided in one pixel 118a so that the position of the central axis of 124 is changed. That is, when the position of the tilting central axis is changed, the tilting angles of the actuators 119a, 119b, and 119c are changed to θ _R , θ _G , and θ _B as shown in FIG. 7.

In addition, according to another embodiment of the present invention, the R-actuator 119a, the G-actuator 119b and the B-actuator 119c as shown in FIG. 8 so that the height of the landing post 125 is different. It is provided in one pixel 118a. Accordingly, the tilting angles of the actuators 119a, 119b, and 119c are changed to θ _R , θ _G , and θ _B as shown in FIG. 8.

The color filters 120a, 120b, and 120c are made of a transmissive material for changing the spectral characteristics of light, and the R-filter 120a for transmitting red light, the G-filter 120b for transmitting green light, and blue light. And a B-filter 120c for permeation. In addition, the flux of light rays passing through the color filters 120a, 120b, and 120c controls the intensity of the light rays reflected from the DMD module 118.

The projection lens 130 projects a color ray beam passing through the three color filters 120a, 120b, and 120c on the screen 132 to display an image corresponding thereto.

Referring to the operation principle of the DMD projector 100 according to the present invention having the above-described structure in more detail as follows.

First, when the DMD projector 100 is driven, the light rays emitted from the halogen metal lamp 111 are condensed into parallel light through the source lens 112 and then irradiated to the source mirror 114. The light rays reflected from the source mirror 114 are primarily irradiated to the DMD module 118 after the optical path is changed.

When the OFF voltage is applied to the DMD module 118, each pixel 118a is turned to the OFF position and the incident color light rays are reflected out of the aperture of the projection lens 130, thereby failing to reach the screen 132.

When the ON voltage is applied to the DMD module 118, in each pixel 118a, the R-actuator 119a is tilted at an angle of θ _R , and the G-actuator 119b is tilted at an angle of θ _G , B-actuator 119c is tilted at an angle of θ _B. In the present invention, three color filters, that is, the R-filter 120a, the G-filter 120b, and the B-filter 120c, are positioned at positions corresponding to the paths of the light rays reflected at angles of θ _R , θ _G , and θ _B. ) Is located.

Thus, the light rays reflected from the R-actuator 119a tilted at an angle of θ _R are irradiated to the R-filter 120a. Since the R-filter 120a transmits only red light, the R-actuator 119a modulates the red light to reflect the light into the aperture of the projection lens 130.

Further, the light rays reflected from the G-actuator 119b tilted at an angle of θ _G are irradiated to the G-filter 120b. Since the G-filter 120b transmits only green light, the G-actuator 119b modulates green light and reflects the light into the aperture of the projection lens 130.

Further, the light rays reflected from the B-actuator 119c tilted at an angle of θ _B are irradiated to the B-filter 120c. Since the B-filter 120c transmits only blue light, the B-actuator 119c modulates blue light to reflect the light into the aperture of the projection lens 130.

In this way, the projection lens 130 projects a light beam comprising red, green and blue color light beams on the screen 132 to form a color image.

As described above, the present invention forms three actuators (i.e., torsion hinges) corresponding to red, green, and blue color light beams in one pixel of the DMD module having an array of reflective pixels that can pivotally rotate, Three color filters are installed between the DMD module and the projection lens. Since the three actuators formed in one pixel of the DMD module are installed to have different tilting angles, light rays reflected from each actuator propagate with different paths and are irradiated to the red filter, the green filter, and the blue filter, respectively. As such, each color ray passing through the red, green and blue filters is projected onto the screen through the projection lens to display a color image.

Therefore, according to the DMD projector according to the present invention, it is possible to implement a color display of high luminance with only one DMD module without light loss.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (8)

A light source 111 for generating light rays; A projection lens 130 for projecting an image onto the screen; An array of reflective pixels 118a disposed between the light source and the projection lens, which can pivot about an axis, and reflect the incident light rays into or out of the projection lens according to an applied image signal to modulate the light rays; And three actuators 119a, 119b, and 119c corresponding to red, green, and blue color light rays in one pixel, and each actuator is deformable at different tilting angles. (118); And And red, green, and blue color filters (120a, 120b, 120c) disposed between the deformable mirror device module and the projection lens. The method of claim 1, wherein the red color filter (120a) is located on the propagation path of the light reflected from the actuator 119a corresponding to the red light, the green color filter 120b is the actuator (119b) corresponding to the green light And a blue color filter (120c) on a propagation path of the light beam reflected from the actuator (119c) corresponding to the blue light beam. The optical projection system according to claim 1, wherein the three actuators (119a, 119b, 119c) are installed in one pixel (118a) such that the position of the tilting central axis is different. The optical projection system of claim 1, wherein the three actuators (119a, 119b, 119c) are installed in one pixel (118a) such that the height of the landing post (125) supporting it is varied. Generating light rays from the light source; Irradiating the light beam generated from the light source to a deformable mirror device module having an array of reflective pixels that can pivot about an axis and having three actuators corresponding to red, green, and blue color light beams in one pixel Doing; Deforming the red, green and blue actuators of the deformable mirror device module with different tilting angles; Dividing the light rays reflected from the deformable mirror device module deformed at different tilting angles into red, green, and blue color filters, thereby dividing the light rays into red, green, and blue color rays; And And projecting each color ray through a projection lens onto a screen. The method of claim 5, wherein the red color filter is located on the propagation path of the light beam reflected from the actuator corresponding to the red light beam, the green color filter is located on the propagation path of the light beam reflected from the actuator corresponding to the green light beam And the blue color filter is positioned on a propagation path of light reflected from an actuator corresponding to the blue light. 6. The projection method according to claim 5, wherein the three actuators are installed in one pixel such that the position of the tilting central axis is different. 6. The projection method according to claim 5, wherein the three actuators are installed in one pixel such that the height of the landing post supporting it is varied.