KR20030083137A - Integrator and Projector using this - Google Patents

Abstract

PURPOSE: An integrator and a projector using the same are provided to reduce volume of an optical system. CONSTITUTION: An integrator has a reflective side(510) formed on an inside of a hollow structure; an opening plate(520) having an opening(521) formed thereon, and attached on one side of the hollow structure; a first polarizing plate(530) slopingly installed on the other side of the hollow structure to separate P-wave and S-wave; and a second polarizing plate(540) at an inside angle of 45 deg. with the first polarizing plate. The opening is a reflective opening allowing light inputted from the outside to permeate but reflecting light inputted from an inside of the integrator so as to prevent light inputted through the opening from going out to the outside through the opening. The reflective side circulates light inputted through the opening within a fixed space until the light goes out through the second polarizing plate. A total reflection mirror surface(522) is formed all over the opening plate except for the opening, and has a lambda/4 plate(523) formed thereon.

Description

Integrator and Projector using this}

The present invention relates to an integrator and a projector, and more particularly, to an integrator for a projector used in an illumination optical system of a projector and a projector using the same.

Recently, display devices have been placed in a trend toward larger screens as well as weight reduction and thinning. In particular, the development of a large-screen display device has emerged as an important problem with the development of multimedia, and one of the developments of such a large-screen display device is a projector.

Projectors, which are such large-screen display devices, are classified into two types, CRT projectors and LCD projectors, according to display elements. LCD projectors have been in the spotlight recently because they can be made relatively small.

1 is a configuration diagram schematically showing a conventional single-panel LCD projector.

Referring to FIG. 1, a conventional single-plate projector includes a lamp 110 for generating light, a parabolic reflector 120 for advancing the light in parallel, and a light propagating through the parabolic reflector 120. The homogeneous fly-eye lens array 130, the polarization converting element 140 for converting the polarization characteristics of the light incident from the fly-eye lens array 130, and the light incident from the polarization converting element 140 is R, Color scroll device 150 for scrolling by dividing the G, B light and a spatial light modulator for selectively modulating the R, G, B light in response to an image signal to implement a predetermined image in space 160 (hereinafter referred to as an 'optical modulator').

In such a conventional projector, the light generated by the lamp 110 proceeds to quasi-parallel light by the parabolic reflector 120, homogenized while passing through the fly's eye lens array 130 as shown in FIG. Through the polarization conversion element 140 as described above has a predetermined polarization characteristics. 2 is a view for explaining the operation principle of a conventional fly's eye lens array, Figure 3 is a view for explaining the operation principle of a conventional polarization conversion element.

Referring to FIG. 2, the fly's eye lens array 130 has a structure in which a plurality of fly's eye lenses having the same shape and shape are arranged in a line, and each of the fly's eye lenses passes through the parabolic reflector 120. A uniform light beam region is formed in the overlapped region (A in FIG. 2) by receiving the advancing non-uniform light beam at different positions.

Meanwhile, referring to FIG. 3, the polarization conversion element 140 converts polarization characteristics of light with a polarizing beam splitter (PBS) array 141 for separating incident light into P and S waves. It consists of two plates 142. The spatially homogenized light via the fly's eye lens array 130 is separated into P waves and S waves by the PBS array 141, and the P waves are λ / 2 plates attached to the rear surface of the PBS array 141. 142 is converted to the S wave. Accordingly, the polarization conversion element 140 can secure the polarization characteristics of the light output uniformly.

However, such a conventional projector uses expensive optical elements such as the fly's eye lens array 130 and the polarization conversion element 140 to homogenize the light incident from the lamp 110 and to polarize the homogenized light. Due to the increase in manufacturing cost, the difficulty of alignment (alignment) due to the use of a plurality of optical elements and there was a number of problems such as increased volume of the optical system.

In particular, the color wheel 150, which is a color scroll device mainly used in a conventional single-plate or two-plate type projector, receives the light of any one component of the white light of the R, G, and B components incident through the polarization conversion element 140. Transmitting and reflecting the remaining light to separate the R, G, B colors in time, and sequentially scroll each of the separated R, G, B colors to implement the color, the reflection in the color separation process and color scroll process There was no means to recapture and reuse the light. Therefore, when using the color wheel 150 composed of R, G, B transmission filter as shown in FIG. 4, there is a problem in that incident light of about 2/3 is lost in the color separation process and the color scroll process.

The present invention was created to solve the above problems, and by performing the optical homogenization process and the polarization conversion process as one optical element, reducing the volume of the optical system, there is an advantage in the alignment (alignment) between the optical elements, In addition, the purpose of the present invention is to provide an integrator having high light utilization rate and a projector using the same by reusing the light that is not actually used in the color separation process and the color scroll process.

1 is a schematic view showing a conventional single-panel LCD projector.

2 is a view for explaining the principle of operation of a conventional fly-eye lens array.

3 is a view for explaining the operation principle of a conventional polarization conversion element.

4 is a view showing a color wheel which is a general color scroll device.

5 illustrates an integrator according to an embodiment of the present invention.

6 illustrates an integrator according to another embodiment of the present invention.

7 is a view illustrating a polarization conversion process in the integrator shown in FIG. 5.

8 is a block diagram showing a projector according to another embodiment of the present invention.

9 is a view for explaining the color drum of FIG.

10 and 11 are views for explaining an optical recapturing process in a projector according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

110 Lamp 120 Parabolic reflector

130 ... fly-lenz array

140 ... Polarization element 150 ... Color scroll device

160 ... Spatial Light Modulator141 ... PBS Array

142 ... λ / 2 plate 510, 610, 831 ... reflective surface

520, 620 ... opening plate 521, 832a ... opening

522, 832b ... total reflection mirror surface 523, 832c ... λ / 4 plate

530, 630, 833 ... first polarizer 540, 640, 834 ... second polarizer

810 Lamp ... 820 Elliptical reflector

830 Integrator 840 Color Drum

850 ... Spatial Light Modulator

In order to achieve the above object, the integrator according to the present invention has an opening in which light generated by an external lamp is incident, and a reflection element and a phase shift element are sequentially formed in a predetermined region except the opening. An opening; A polarizer which emits only a predetermined linearly polarized light out of the light incident through the opening; And an optical recycling unit for recycling the light incident through the opening in the predetermined space until the light is emitted through the polarizing unit. Characterized in that it comprises a.

In the opening, the opening is a reflective opening, the reflection element is an internal reflection or a reflection mirror, and the phase shift element is a λ / 4 plate.

The polarizing unit includes first and second polarizing plates constituted by reflective P / S wave separation means. At this time, the first polarizing plate is located on the optical path of the opening and the second polarizing plate, it is preferable that the second polarizing plate and the installed with an internal angle of 45 °.

The optical recycling unit may be formed of a hollow rectangular cylinder or a mirrored glass rod in which a reflective surface is formed in a predetermined region of an inner surface.

On the other hand, the projector according to the present invention for achieving the above object comprises a lamp for generating white light; An elliptical reflector for condensing the white light; A scroll unit for dividing the incident light into R, G, and B lights to perform color scrolling; An integrator that polarizes the light collected by the ellipsoidal reflector and enters the scroll unit, and recycles the reflected light and reincarnates the scroll unit; And a spatial light modulator for selectively modulating the R, G, and B lights to form an image in space. Characterized in that it comprises a.

Here, the openings of the lamp and integrator are preferably located at the first and second focal points of the virtual ellipse defined by extending the elliptical reflector.

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

5 illustrates an integrator according to an embodiment of the present invention, and FIG. 6 illustrates an integrator according to another embodiment of the present invention.

Referring to FIG. 5, the integrator includes a reflective surface 510 formed on an inner surface of a hollow structure, and an opening plate 520 having an opening 521 formed on one side of the hollow structure. On the other side, the first polarizing plate 530 for separating P / S waves is inclined. The second polarizing plate 540 is provided at a position having a predetermined internal angle with the first polarizing plate 530.

The opening 521 is a reflective opening that transmits light input from the outside but reflects light input inside the integrator, so that light input through the opening 521 is output to the outside through the opening 521. To prevent them.

The first polarizing plate 530 and the second polarizing plate 540 preferably have an inner angle of about 45 °, and the reflective surface 510 formed on the rear side of the first polarizing plate 530 has a first polarizing plate as shown in FIG. 6. It may be directly formed on the rear portion of the (630).

Referring back to FIG. 5, the reflective surface 510 is a means for circulating the light in a predetermined space until the light input through the opening 521 is output through the second polarizing plate 540. Although the total reflection mirror is attached to the inner surface of the hollow structure having the rectangular cross section (hallow type), it can be formed on the inner surface of the hollow structure having the cross section of circular or rectangular polygons, for example, octagon and octagon. If the total reflection effect is used, it can be configured as a glass bar (solid type).

In the opening plate 520, a total reflection mirror surface 522 is formed in an area excluding the opening 521, and a λ / 4 plate 523 is formed thereon.

The first and second polarizing plates 530 and 540 are means for converting unpolarized light incident through the opening 521 into predetermined polarized light, and the first polarizing plate 530 is a S-wave light. Reflective P / S wave separation means for reflecting and transmitting P wave light is used, and reflective P / S wave separation means for reflecting P wave and transmitting S wave is used for the second polarizing plate 540. Here, as the reflective P / S wave separation means, a PBS or a PBS beam splitter or a reflective polarizer may be used.

The integrator having the above configuration has a light homogenization process of spatially homogenizing and outputting the heterogeneous light incident through the opening 521, and converting the unpolarized light incident through the opening 521 into a predetermined polarization state. And a light recapturing process for recycling the light returned to the inside of the integrator through the second polarizing plate 540 and outputting the light again through the second polarizing plate 540. . Since the optical recapturing process functions in conjunction with color scroll devices such as color drums and color wheels, the optical recapturing process is particularly useful in single- or two-plate projectors in which such color scroll devices are used.

First, the optical homogenization process will be described as follows.

The light input through the opening 521 is a plurality of light beam bundles traveling to different light paths, and the light propagating paths of the light beams are different from each other so that a homogeneous light beam cannot be obtained. That is, the light density in the space where the traveling light paths of the light beams coincide is large, and the light density in the mismatched space is small. However, in the integrator, the reflective surface 510 that provides the optical circulation recycle is formed relatively long, whereas the second polarizing plate 540, which is an area where light is output, is formed relatively small. The structure of the integrator significantly limits the optical path of the light rays output through the second polarizing plate 540, and consequently reduces the difference in the propagation optical path of the respective light rays. Thus, the light rays output from the second polarizing plate 540 are homogenized while the optical paths overlap each other at a predetermined spatial position.

Next, the polarization conversion process will be described with reference to FIG. 7. FIG. 7 is a diagram illustrating a polarization conversion process in the integrator shown in FIG. 5.

The light input through the opening 521 passes through the reflecting surface 510 or proceeds directly to the first polarizing plate 530 according to the angle of incidence, and passes through the first polarizing plate 530. Separated into S-waves, they travel in different optical paths.

In this case, the S-polarized light reflected by the first polarizing plate 530 passes through the second polarizing plate 540 and is emitted to the outside, but the P-polarized light passing through the first polarizing plate 530 is located on the rear side of the reflective surface ( After reentering the first polarizing plate 530 via 510, the λ / 4 plate 523 located on the opposite side is reached.

The P-polarized light is transmitted through the λ / 4 plate 523, and its phase is changed by λ / 4, and is again transmitted through the λ / 4 plate 523 by the total reflection mirror surface 522 thereunder. The phase is changed by λ / 4. Therefore, the P-polarized light first incident on the λ / 4 plate 523 is emitted after changing its phase by λ / 2. That is, the first P-polarized light is emitted as S-polarized light.

Subsequently, the S-polarized light reaches and reflects on the first polarizing plate 530 positioned on the opposite side thereof, and is then output to the outside through the second polarizing plate 540.

As described above, since the integrator converts and outputs most of the light input through the optical recycle into a predetermined polarized light, there is little light loss in the polarization conversion process.

Next, the optical recapturing process will be described.

8 is a configuration diagram showing a projector according to another embodiment of the present invention.

Referring to FIG. 8, the projector may include a lamp 810 for generating light, an elliptical reflector 820 for reflecting the light generated by the lamp 810 and condensing the light at a predetermined position, and the incident light R, A color drum 840 which divides into G and B lights to perform color scrolling; An integrator 830 for polarizing the light collected through the ellipsoidal reflector 820 to be incident on the color drum 840, and recycling the reflected light to reenter the color drum 840; And a spatial light modulator 850 (hereinafter, referred to as an optical modulator) for selectively modulating the R, G, and B lights in response to an image signal to form an image in space. Characterized in that it comprises a.

The lamp 810 is positioned at a first focal point of the virtual ellipse defined by extending the reflecting surface of the ellipsoidal reflector 820, and the opening of the integrator 830 is formed at the second focal point of the virtual ellipse. do. Accordingly, the light generated by the lamp 810 is reflected by the ellipsoidal reflector 820 and is collected in the opening of the second focus, that is, the integrator 830, and the collected light is integrator 830 through the opening. ) Is entered.

The color drum 840 has a cylindrical transmissive surface as shown in FIG. 9, and the dichroic coating is applied to the transmissive surface to selectively transmit R, G, and B light. The transmission surface has a structure in which R, G, and B filter cells 840a, 840b, and 840c, which transmit only light of R, G, or B components, are alternately disposed among the incident light. The color drum 840 rotates at a constant speed by a rotation driving device to divide the incident white light into R, G, and B lights in time, and sequentially emits the divided R, G, and B lights to realize color. As a color scroll device, it may be replaced by another common color scroll device such as a color wheel. 9 is a view for explaining the color drum of FIG.

The optical modulator 850 is an optical system in which a lens array 851, a PBS 852, a liquid crystal panel 853, and a projection lens unit 854 are coupled to each other. The optical modulator 850 is separated in time through the color drum 840. By adjusting the amount of transmitted light of each of the R, G, and B lights corresponding to the image signal applied to the liquid crystal panel 853, a predetermined image image is generated, which is enlarged and imaged through the projection lens unit 854.

Hereinafter, the operation of the projector will be described with reference to FIGS. 8 to 11. 10 and 11 are diagrams for describing an optical recapturing process in a projector according to another embodiment of the present invention.

The white light generated by the lamp 810 is reflected by the ellipsoidal reflector 820 and then collected, and passes through the integrator 830 to become a predetermined polarized light to form each filter cell 840a of the color drum 840 ( 840b) and 840c.

Each of the filter cells 840a, 840b, and 840c transmits light that satisfies the transmission condition of the filter among incident polarized light to the light splitter 850, but the remaining light that does not satisfy the transmission condition passes the integrator ( 830).

For example, if the white polarized light output from the integrator 830 is incident on the R filter cell 840a, among the R, G, and B lights constituting the white polarized light, the R light proceeds to the light splitter 850. The remaining G and B light is reflected by the R filter cell 840a and returned to the integrator 830.

Thereafter, the G and B lights are recycled into the integrator 830 and then re-injected into the respective filters 컬러 of the color drum 840 through the second polarizing plate 834, where the G and B lights are G If incident on filter cell 840b, G light proceeds to light splitter 850, and the remaining B light is reflected off G filter cell 840b to return back to the integrator 830 to repeat the process. do.

As a result, polarized light emitted from the first integrator 830 passes through the color drum 840 while undergoing the recapturing process as described above. Less light loss during color scrolling

Subsequently, the R, G, and B light split in time while passing through the color drum 840 are incident on the PBS 852 via the lens array 851, and the PBS 852 is connected to the liquid crystal panel 852. A color image corresponding to an image signal is realized by interlocking. The image is enlarged and imaged on a screen or the like through the projection lens unit 854.

As described above, the above embodiments are disclosed for the purpose of illustration, and those skilled in the art will appreciate that various modifications, improvements, substitutions, and additions may be made without departing from the spirit of the present invention. Accordingly, the technical scope of the present invention should be defined by the appended claims.

As described above, the integrator and the projector using the same according to the present invention can reduce the total volume of the projector by performing the optical homogenization process and the polarization conversion process with one optical element, and the optical elements (especially, the optical homogenization element) And solve the alignment problem (polarization conversion element).

In addition, the integrator according to the present invention has a high light utilization rate, because it enables to recapture and reuse some light that has not been substantially used in the color separation process and the color scroll process through a color scroll device, etc. Has the effect of realizing a high brightness image.

Claims (12)

An opening through which an opening in which light generated by an external lamp is incident is formed, and in which a reflection element and a phase shift element are sequentially stacked in a predetermined region except the opening; A polarizer which emits only a predetermined linearly polarized light out of the light incident through the opening; And An optical recycling unit for recycling the light incident through the opening in the predetermined space until the light is emitted through the polarizing unit; Integrator comprising a. The method of claim 1, wherein the opening of the opening, An integrator characterized by a reflective aperture. The method of claim 1, wherein the reflective element of the opening, Integrator characterized by total internal reflection or reflection mirror. According to claim 1, The phase shift element of the opening, Integrator characterized by a λ / 4 plate. The method of claim 1, wherein the polarizing portion, An integrator comprising first and second polarizing plates constituted by reflective P / S wave separation means. The method of claim 5, wherein the first polarizing plate, It is located on the optical path of the opening and the second polarizing plate, the integrator, characterized in that it is installed with the second polarizing plate with an angle of 45 °. The method of claim 1, wherein the optical recycle portion, An integrator characterized in that the cavity is a hollow cylinder (reflection surface) is formed in a predetermined area of the inner surface. The method of claim 1, wherein the optical recycle portion, Integrator characterized by a mirrored glass rod. A lamp for generating white light; An elliptical reflector for condensing the white light; A scroll unit for dividing the incident light into R, G, and B lights to perform color scrolling; An integrator that polarizes the light collected by the ellipsoidal reflector and enters the scroll unit, and recycles the reflected light and reincarnates the scroll unit; And A spatial light modulator for selectively modulating the R, G, and B lights to form an image in space; Projector comprising a. The method of claim 9, wherein the integrator, An opening through which an opening in which light generated by the lamp is incident is formed, and in which a reflection element and a phase shift element are sequentially formed in a predetermined region except the opening; A polarizer which emits only a predetermined linearly polarized light out of the light incident through the opening; And An optical recycling unit for recycling the light incident through the opening in the predetermined space until the light is emitted through the polarizing unit; Projector comprising a. The method of claim 10, wherein the opening of the lamp and the integrator, And a projector positioned at the first and second focal points of the virtual ellipse defined by extending the elliptical reflector. The method of claim 9, wherein the scroll unit, Projector characterized by a color drum.