KR20060062900A - Color display apparatus using polarized light - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device, and in particular, each of a plurality of lights is separated into P-polarized light and S-polarized light, and then optically modulated on the separated P-polarized light and S-polarized light to generate diffracted light, The present invention relates to a color display device using a polarizing beam that is synthesized and projected onto a screen.

Color display device, light modulator, polarized beam

Description

Color display apparatus using polarized beams             

1 illustrates a conventional laser scanning method using a single light source and an f-θ lens.

2 is a diagram illustrating a conventional laser scanning method for performing laser scanning by a multi-beam formed by an LED array configured in an image head.

3 is a block diagram of a color display device having a virtual single light source according to a conventionally improved technique.

4 is a block diagram of a color display device using a polarizing beam according to an embodiment of the present invention.

5 is a perspective view, side cross-sectional view, and cross-sectional view including an optical path of the illumination lens of FIG.

FIG. 6 is a view for explaining a diffraction angle of pass polarized incident light incident on the diffractive optical modulator of FIG. 4. FIG.

FIG. 7 is a perspective view of the diffractive optical modulator of FIG. 4. FIG.

8 is a view for explaining a diffraction angle of split polarized incident light incident on the diffractive optical modulator of FIG. 4.

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

400: light source system 410: polarized light separating unit

420: condenser 430: illumination lens system

440: beam splitter 450: optical modulator

460: reflection mirror 470: filter system

480: projection system 490: screen

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device, and in particular, each of a plurality of lights is separated into P-polarized light and S-polarized light, and then optically modulated on the separated P-polarized light and S-polarized light to generate diffracted light, The present invention relates to a color display device using a polarizing beam that is synthesized and projected onto a screen.

The light beam scanning device is an image forming apparatus such as a laser printer, a display device, an LED printer, an electrophotographic copying machine, a word processor, or the like, which scans a light beam and spots the light beam onto a photosensitive medium to form an image image.

The light beam scanning apparatus has been steadily researched and developed to have the characteristics of miniaturization, high speed, and high resolution as the image forming apparatus is developed in the direction of miniaturization, high speed, and high resolution.

The light beam scanning device of the image forming apparatus can be roughly classified into a laser scanning method using an f · θ lens and an image head printer method according to the light beam scanning method and the configuration of the light beam scanning device.

Fig. 1 shows a conventional laser scanning device using a f? Lens.

As shown, a conventional laser scanning apparatus includes a laser diode (LD) 10 for emitting a light beam according to a video signal, a collimator lens 11 for converting the light beam output from the LD 10 into parallel light, Cylindrical lens 12 which makes the parallel light which passed through the collimator lens 11 into a horizontal linear light with respect to a scanning direction, and the horizontal linear light which passed through the cylinder lens 12 at the isoline speed are scanned. A polygon mirror 13, a polygon mirror driving motor 14 for rotating the polygon mirror 13 at a constant speed, and a light at an equiangular velocity reflected from the polygon mirror 13 with a constant refractive index with respect to the optical axis. The f · θ lens 15 for deflecting in the direction and correcting the aberration to focus on the irradiated surface, and the surface of the photosensitive drum 17 as an image plane by reflecting a light beam through the f · θ lens 15 in a predetermined direction. Phased into Receives and synchronizes a laser beam reflected by the horizontal synchronous mirror 18 and a horizontal synchronous mirror 18 for reflecting the laser beam through the image forming reflection mirror 16, the f? Lens 15 in a horizontal direction. It is configured to include an optical sensor 19 to fit.

The laser scanning method is difficult to obtain high speed printing due to the low switching speed of the laser diode 10 and the scanning speed of the polygon mirror 13.

That is, in order to increase the scanning speed of the light beam, the polygon mirror 13 should be rotated by using a higher speed motor. In this case, the high speed motor is expensive and the high speed motor causes heat, vibration and noise. Therefore, there is a problem such as lowering the operation reliability, it is not expected to greatly increase the scanning speed.

Another method of improving the speed of the optical scanning device is an image head printing method using a multi-beam type beam forming apparatus.

Such a multi-beam optical scanning device has a plurality of light emitters (laser apex) as a light source means, and a plurality of light beams emitted by the plurality of light emitters by means of an imaging lens via an optical reflector. By imaging, the recording medium surface is simultaneously optically scanned with a plurality of light spots formed on the recording medium surface.

In order to achieve high speed printing using only one light spot, the number of optical scanning of the recording medium surface per unit time should be very large, so that the rotational speed of the light reflector, image clock, etc. Optical scanning cannot be followed. Therefore, if the number of beam spots simultaneously scanning the recording medium surface increases, the rotational speed, image clock, etc. of the light reflector decreases in inverse proportion to the number of beam spots.

As the most effective method of forming a plurality of beam spots, a laser element serving as a light source has a plurality of light emitting points (light emitting portions) that can be driven independently.

Such laser devices having a plurality of light emission points are generally referred to as "monolithic multi-beam laser elements". When monolithic multi-beam laser elements are used, the various optical elements placed behind the light source can usually be used by multiple beams of rays, providing great advantages in cost, operation, control, and the like.

2 is a diagram illustrating a conventional laser scanning method for performing laser scanning by a multi-beam formed by an LED array configured in an image head.

Referring to FIG. 2, a multi-beam is formed by forming a large amount of LED array 21 to fill printing paper in the image head 20, so that unlike a laser scanning method, a polygon mirror and a f-θ lens are not used. By printing one line at a time at the same time, print speed can be significantly improved.

Such monolithic multi-beam laser elements include, for example, so-called surface emitting lasers (surface emitting semiconductor lasers).

Surface emitting lasers emit emission beams parallel to the thickness direction of the silicon layer, whereas conventional semiconductor lasers emit light beams in a direction perpendicular to the thickness direction of the silicon layer.

The surface emitting laser has the following characteristics. That is, conventional semiconductor lasers emit elliptical cross-sections and emit divergent rays of varying divergence angles, while surface emitting lasers can emit circular beams with stable divergence angles.

However, surface emitting lasers have a problem of unstable polarization direction of the output light beam. Although the polarization direction can be adjusted to some extent by the manufacturing method, the polarization direction varies with the light emission point, the ambient temperature, and the output.

Usually the reflectance, transmittance of optical elements that make up an optical scanning device such as a polygonal mirror such as a light reflector, a scanning lens as an imaging optical system (f-theta), an echo mirror to change the optical path, and the like, And the angle characteristic changes according to the polarization direction of the input light beam.

For this reason, when a monolithic multi-beam laser element including a surface emitting laser is used as a light source of an optical scanning device, a plurality of beam spots that optically scan the recording medium surface are located at different polarization directions of individual light emission points. According to different strengths. And, this difference in intensity appears as pitch unevenness in the image, which significantly reduces the image quality.

In order to solve this problem, Korean Patent Application No. 2003-77391 uses a plurality of diffraction beams formed by a piezoelectric / electric distortion diffraction type optical modulator composed of an actuating cell driven on / off by a driving voltage applied from the outside. Disclosed is a scanning apparatus using a piezoelectric / electric distortion diffraction type optical modulator that performs high speed scanning.

A scanning apparatus using a piezoelectric / electric distortion diffraction type optical modulator according to the disclosed improved technique includes: first lens means for horizontally scanning a single beam output from a predetermined light source in a direction of an optical path; It consists of a plurality of actuating cells to drive on / off by the drive power applied from the outside, and the plurality of diffraction beams from the single beam by the reflection and diffraction phenomenon by the on / off driving between the actuating cells Piezoelectric / electric distortion diffraction type optical modulators; A slit for performing filtering on a diffraction beam having a predetermined diffraction coefficient among a plurality of diffraction beams incident from the piezoelectric / electric distortion diffraction type optical modulator; And second lens means for irradiating a photosensitive surface of the photosensitive member with a diffraction beam having a predetermined diffraction coefficient selectively filtered by the slit.

On the other hand, when the scanning device using the piezoelectric / electric distortion diffraction type optical modulator according to the conventional improved technique as described above is used for color display or printing, λ ₁ , λ ₂ , λ ₃ .. Since there is a different slit interval for the wavelength of each color, the development of a color display device accordingly has been requested.

3 is a block diagram of a display device using color-coded slits according to the prior art.

Referring to the drawings, a display apparatus using color-coded slits according to the related art includes a plurality of light sources 300, an illumination lens 310, a synthesis system 320, a fourier filter 330, and a projection system 340. , Screen 350.

Herein, the illumination lens 310 converts each beam of the plurality of beams output from the plurality of light sources 300 into linear light in a horizontal direction with respect to the optical path direction and focuses the diffraction type optical modulators 321a to 321c to be described later. It consists of many cylinder lenses 311a-311c and collimation lenses 312a-312c.

Here, each of the plurality of collimation lenses 311a to 311c converts spherical light incident from the plurality of light sources 300 through the cylinder lenses 311a to 311c into parallel light, and then corresponds to the corresponding diffraction type optical modulator. Incident at 321a to 321c.

Then, the cylinder lenses 311a to 311c are horizontally incident on the corresponding diffraction type optical modulators 321a to 321c which horizontally position each parallel light incident from the light sources 310a to 310c in the optical path direction. In order to achieve this, the balanced light is converted into linear light in the horizontal direction, and incident to the diffractive light modulators 321a to 321c through the corresponding collimation lenses 312a to 312c.

The synthesis system 320 includes a plurality of diffractive light modulators 321a to 321c and beam splitters 322. The diffractive light modulators 321a to 321c diffract incident light to emit diffracted light, and a beam The splitter 322 synthesizes and emits a plurality of diffracted lights.

Fourier filter 330 is composed of a projection lens 331 and the color-specific slit 332, and transmits only the diffraction light of the desired order of the incident diffraction light. That is, the projection lens 331 separates and exits the order of the incident light, and the color-specific slit 333 transmits only the diffraction light of the desired order among the incident diffracted light.

Projection system 340 projects the incident diffracted light onto screen 350. That is, the projection system 340 focuses a diffraction beam having a predetermined diffraction coefficient incident through the color-specific slit 332 on the screen 350 to form a spot, and more specifically, projection It is a lens.

On the other hand, when using non-polarized light as in the prior art, a large amount of light loss occurs in the beam splitter, and the transmission reflection characteristics are poor in the beam splitter, thereby affecting different colors and thus reducing color purity.

In order to satisfy the above-described request, the present invention generates a diffracted light by using a polarized beam and modulates light with respect to the separated P-polarized light and S-polarized light, and then synthesizes the generated diffracted light, and then only the diffracted light of the desired order is synthesized. It is an object of the present invention to provide a display device using a polarizing beam that can be filtered and projected onto a screen.

The present invention for achieving the above object, the polarization separation unit for separating each of the plurality of light emitted from the plurality of light sources to the first polarized light and the second polarized light; An illumination lens system positioned on the optical path of the first polarization and the optical path of the second polarization and converting the plurality of first polarizations and the plurality of second polarizations separated by the polarization splitter into linear parallel light, respectively; A polarization converting unit positioned on the optical path of the second polarization to convert the second polarization into the first polarization; A plurality of diffraction type optical modulators modulating incident light of a corresponding wavelength to generate and emit diffracted light having a plurality of diffraction orders; The first polarized light converted by the illumination lens system into linear parallel light is incident on the diffraction type optical modulator, and the second polarized light converted by the illumination lens into linear parallel light and changed into the first polarized light by the polarization converter. An incident field incident on the diffractive optical modulator so as to be symmetrical with a first polarization; A filter system for passing diffracted light of a desired order to each diffracted light emitted from the plurality of diffractive light modulators; And a projection system for focusing and scanning a plurality of diffracted light filtered by the filter system on a target object.

Hereinafter, a configuration of a display apparatus using a polarizing beam according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a block diagram of a display device using a polarizing beam according to an embodiment of the present invention.

Referring to the drawings, the display device using a polarizing beam according to an embodiment of the present invention, the light source system 400 consisting of a plurality of light sources (401a ~ 401c), a plurality of polarizing beam-splitter (PBS) Polarizing separator 410 consisting of 411a to 411c and half-wave plates 412a to 412c, and a light collecting part consisting of one mirror 421ac and 421bc and a plurality of color-specific mirrors 421aa, 421ab, 421ba, and 421bb. 420a and 420b, illumination lens systems 430a and 430b consisting of cylinder lenses 431a and 431b and collimator lenses 432a and 432b, first reflecting mirror 433, polarizing beam splitter 440, and multiple diffraction types A light modulation system 450 including a light modulator 451a to 451c, a second reflection mirror 460, a filter system 470 including a projection lens 471 and a color filter 472, and a pair of projection lenses Projection system 480, screen 490, consisting of 481, 482, speckle remover 481, and galvano mirror 484.

The plurality of light sources 400 include, for example, a red light source 401a, a green light source 401b, and a blue light source 401c. The light sources 400 used herein may be light sources manufactured using semiconductors such as light emitting diodes (LEDs) and laser diodes (LDs). Such semiconductor light sources have many properties suitable for use in color display devices compared to other light sources.

The polarization beam splitters 411a to 411c positioned in front of each of the light sources 401a to 401c pass polarization components that are perpendicular to each other in the incident light, and the two components of the incident light are separated from each other on a diagonal surface. In the present invention, the polarization beam splitter 411a located in front of the red light source 401a passes S polarized light (herein referred to as a pass polarized red S beam) and reflects P polarized light (called a split polarized red P beam). The polarization beam splitter 411b positioned at the front end of the green light source 401b passes the P-polarized light and reflects the S-polarized light. The polarization beam splitter 411c positioned at the front end of the blue light source 401c passes the S-polarized light. P polarized light is reflected.

The half-wave plate of 412a is emitted by changing the P-polarized light reflected from the polarization beam splitter of 411a to S-polarized light, and the half-wave plate of 412b represents the S-polarized light reflected from the polarization beam splitter of 411b. The light is converted into P-polarized light, and the half-wave plate 412c is emitted by changing the P-polarized light reflected from the polarization beam splitter 411c to S-polarized light.

The reflection mirror 421ac of the light collecting portion 420a reflects the blue S-polarized light emitted from the blue light source 401c and passed through the polarization beam splitter 411c to the illumination lens system 430a, and is referred to as 421ab. The color-selective mirror of the light transmits the blue S polarized light incident from the reflecting mirror 421ac, and the green P polarized light emitted from the green light source 401b and passed through the polarizing beam splitter 411b is reflected by the illumination lens system 430a. do.

Further, the dichroic mirror denoted by 421aa transmits the blue S polarization and the green P polarized light incident from the dichroic mirror 421ab at the front end, and passes through the polarization beam splitter 411a from the red light source 401a. S polarized light is reflected toward the illumination lens system 430a.

As described above, when the S-polarized light of the blue color, the P-polarized light of the green color, and the S-polarized light of the red color are condensed by one reflection mirror 421ac and the plurality of color-mirror mirrors 421aa and 421ab, the illumination lens system 430a collects light. The multiple beams are converted into linear parallel light and incident on the beam splitter 440.

An example of a cross-sectional view of the light source 400 used here is shown in FIG. 5A. Referring to FIG. 5A, the cross section of the light source 400 is circular, and the intensity profile of the light is shown in FIG. As shown in (B), it has a Gaussian distribution.

The illumination lens system 430a changes the incident light into linear parallel light having an elliptical cross section. The illumination lens system 430a includes a cylinder lens 431a and a collimator lens 432a.

That is, the illumination lens system 430a converts the multiple beams collected by the condenser 420a into linear light in the horizontal direction with respect to the optical path direction, and then converts the multiplexed beams into the diffractive light modulators 451a to 451c through the beam splitter 440. Let it enter.

Here, the cylinder lens 431a is configured to horizontally incident light incident from the condenser 420a to the corresponding diffraction type optical modulators 451a to 451c horizontally positioned in the optical path direction. As shown in FIG. 2, the balanced light is converted into linear light in the horizontal direction, and is incident on the diffractive light modulators 451a to 451c through the corresponding collimator lens 452a.

Here, the collimator lens 451a converts spherical light incident from the condenser 420a through the cylinder lens 451a into parallel light, and then enters the collimator lens 451a into the corresponding diffractive light modulators 451a to 451c.

As shown in FIG. 5, the collimator lens 432a includes a concave lens 432aa and a convex lens 432ab.

The concave lens 432aa extends the linear light incident from the cylinder lens 431a up and down as shown in FIG. 5D to enter the convex lens 432ab. The convex lens 432ab emits incident light incident from the concave lens 432aa by changing parallel light as shown in Fig. 5E. In Figure 5 (a) is a perspective view of an optical system consisting of a light source, a cylinder lens, a collimator lens, (b) is a plan view in Figure 5, (c) is a side cross-sectional view, Figure 5 (d) is a cut surface. It is also.

On the other hand, the first diagonal surface 441 of the beam splitter 440 reflects blue S-polarized light and enters the blue diffraction type optical modulator 451c, and transmits green P-polarized light and red S-polarized light.

Next, the second diagonal surface 442 of the beam splitter 440 is transmitted when the green P polarized light is incident to the green diffraction type optical modulator 451b, and is reflected when the red S polarized light is incident to reflect the red diffraction for red. It enters into the fluorescent modulator 451a.

Each of the diffractive light modulators 451a to 451c diffracts each linear light incident from the beam splitter 440 to form diffracted light, and then reenters the formed diffracted light into the beam splitter 440.

At this time, the diffraction angle of the diffracted light formed by the diffractive light modulators 451a to 451c is proportional to the wavelength, and it is necessary to make the diffracted light of the order desired to be used to be emitted vertically from the diffractive light modulators 451a to 451c. In the case where it is desired to use the + 1st order diffracted light as shown in FIG. 6, the + 1st order diffracted light is emitted vertically when the incident angle is equal to the diffraction angle of the + 1st order diffracted light.

Here, the diffractive light modulators 451a to 451c may use various types of diffractive light modulators, and an example of the open hole-based diffractive light modulator is illustrated in FIG. 7.

Referring to the drawings, the open hole-based diffractive light modulator is composed of a silicon substrate 701, an insulating layer 702, a lower micromirror 703, and a plurality of elements 710a to 710n. Here, although the insulating layer and the lower micromirror are configured as separate layers, if the insulating layer has a property of reflecting light, the insulating layer itself can function as the lower micromirror.

The silicon substrate 701 has depressions to provide air space to the elements 710a to 710n, an insulating layer 702 is stacked, and a lower micromirror 703 is deposited thereon, and the depressions The lower surfaces of the elements 710a to 710n are attached to both sides that deviate. As the material constituting the silicon substrate 701a, a single material such as Si, Al ₂ O ₃ , ZrO ₂ , Quartz, SiO _2, etc. is used. It can also form using.

The lower micromirror 703 is deposited on the silicon substrate 701 and reflects and diffracts incident light. As the material used for the lower micromirror 703, metal (Al, Pt, Cr, Ag, etc.) may be used.

The elements (typically, only the reference numeral 710a is described but the rest are the same) have a ribbon shape, and the bottom surfaces of both ends are recessed in the silicon substrate 701 so that the center portion is spaced apart from the recessed portion of the silicon substrate 701. The lower support part 711a which is attached to the both side area | regions which deviate from a part is provided.

Piezoelectric layers 720a and 720a 'are provided on both sides of the lower support 711a, and the driving force of the element 710a is provided by contraction and expansion of the provided piezoelectric layers 720a and 720a'.

The material constituting the lower support 711a includes Si oxide (for example, SiO2), Si nitride series (for example, Si ₃ N _4, etc.), ceramic substrate (Si, ZrO ₂ , Al ₂ O _3, etc.), Si carbide And so on. The lower support 711a can be omitted as necessary.

The left and right piezoelectric layers 720a and 720a 'are stacked on the lower electrode layers 721a and 721a' for providing the piezoelectric voltage and the lower electrode layers 721a and 721a ', and contract and expand when voltage is applied to both surfaces. The upper electrode layers 723a, which are stacked on the piezoelectric material layers 722a and 722a 'that generate vertical driving force, and which provide piezoelectric voltages to the piezoelectric material layers 722a and 722a'. 723a '). When voltage is applied to the upper electrode layers 723a and 723a 'and the lower electrode layers 721a and 721a', the piezoelectric material layers 722a and 722a 'contract and expand to generate vertical movement of the lower support 711a.

As the electrode material of the electrodes 721a, 721a ', 723a, 723a', Pt, Ta / Pt, Ni, Au, Al, RuO _2, etc. may be used, and may be sputtered or evaporated in a range of 0.01-3 μm. Deposit.

On the other hand, the upper micro mirror 730a is deposited on the central portion of the lower support 711a and has a plurality of open holes 731a1 to 731a3. Here, the shape of the open holes 731a1 to 731a3 is preferably rectangular, but any closed curve such as circular or elliptical may be used. If the lower supporter is formed of a light reflective material, it is not necessary to deposit the upper micromirror separately, and the lower supporter may function as the upper micromirror.

The open holes 731a1 to 731a3 allow incident light incident on the element 710a to pass through to the lower micromirror 703 corresponding to a portion where the open holes 731a1 to 731a3 are formed. The mirror 703 and the upper micromirror 730a may form pixels.

That is, for example, the (i) portion of the upper micromirror 730a and the (i) portion of the lower micromirror 703 in which the open holes 731a1 to 731a3 are formed may form one pixel.

At this time, incident light incident through the portions where the open holes 731a1 to 731a3 of the upper micromirror 730a are formed may be incident on a corresponding portion of the lower micromirror 703 and the upper micromirror 730a and the lower micromirror. The maximum diffracted light is generated when the interval 703 becomes an odd multiple of lambda / 4. In addition, the open-hole diffraction optical modulator usable in the present invention is disclosed in Korean Application No. P2004-030159.

On the other hand, the reflecting mirror 421bc of the light collecting part 420b is emitted from the blue light source 401c and reflected by the polarization beam splitter 411c, and the blue S polarized light whose polarization is converted from the half-wave plate 412c is an illumination lens system. Reflected toward (430b), the color-coded mirror of reference numeral 421bb passes through the S-polarized light of blue incident from the reflecting mirror 421bc and exits from the green light source 401b to be reflected by the polarizing beam splitter 411b and is a half-wave plate. At 412b, the green P-polarized light whose polarization is converted is reflected to the illumination lens system 430b.

Further, the dichroic mirror denoted by 421ba transmits the blue S polarization and the green P polarized light incident from the dichroic mirror 421bb in front, and passes through the polarization beam splitter 411a from the red light source 401a and is half wave. The red S-polarized light that has been polarized by the lamella 412a is reflected toward the illumination lens system 430b.

When the S-polarized light of the blue, the P-polarized light of the green, and the S-polarized light of the red are condensed by the single reflection mirror 421bc and the plurality of color-mirror mirrors 421ba and 421bb, the illumination lens system 430b collects the light. The multiple beams are converted into linear parallel light and incident on the beam splitter 440.

The first diagonal surface 441 of the beam splitter 440 reflects the blue S-polarized light and enters the blue diffraction type optical modulator 451c, and transmits the green P-polarized light and the red S-polarized light.

Next, the second diagonal surface 442 of the beam splitter 440 is transmitted when the green P polarized light is incident to the green diffraction type optical modulator 451b, and is reflected when the red S polarized light is incident to reflect the red diffraction for red. It enters into the fluorescent modulator 451a.

Each of the diffractive light modulators 451a to 451c diffracts each linear light incident from the beam splitter 440 to form diffracted light, and then reenters the formed diffracted light into the beam splitter 440.

The diffraction angle of the diffracted light formed by the diffractive light modulators 451a to 451c is proportional to the wavelength, and the diffracted light of the order desired to be used needs to be emitted vertically from the diffractive light modulators 451a to 451c. In the case where it is desired to use -1st order diffracted light as shown in Fig. 8, when the incident angle is equal to the diffraction angle of the -1st order diffracted light, the -1st order diffracted light is emitted vertically.

At this time, in the present invention, if the incident angles of the pass-polarized light and the split-polarized light incident on the diffraction type optical modulators 451a to 451c are equal in symmetry and the same size as the diffraction angle, the pass-polarized light will be referred to FIGS. The -first-order diffraction light generated by the first order and the -first-order diffraction light generated by the separated polarization are synthesized with each other to obtain the best light efficiency. Of course, since the diffracted light has a discrete distribution, the incident angle does not necessarily need to be the same as the diffraction angle.

 On the other hand, the beam splitter 440 collects the diffracted light generated by each of the diffractive light modulators 451a to 451c and enters the reflective mirror 460, and the reflective mirror 460 filters the incident diffracted light. Incident to the system 470.

The filter system 470 is preferably composed of a projection lens 471 and a filter 472, the projection lens 471 separates the incident diffraction light for each order, and the filter 472 only the diffraction light of the desired order Permeate.

Projection system 480 includes a pair of projection lenses 481 and 483 and speckle remover 482 to project incident diffracted light onto screen 490. That is, the projection system 480 focuses a diffraction beam having a predetermined diffraction coefficient incident through the filter system 470 on the screen 490 to form a spot.

According to the present invention as described above, there is an effect to prevent the amount of light loss by performing light modulation and synthesis using polarized light.

In addition, according to the present invention, it is possible to improve the transmission reflection characteristics by using polarized light so as not to affect other colors, thereby improving color purity.

Herein, the present invention described above has been described with reference to preferred embodiments, but those skilled in the art will variously modify the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. And can be changed.

Claims (4)

A polarization separator configured to separate and emit each of the plurality of lights emitted from the plurality of light sources into first and second polarizations; An illumination lens system positioned on the optical path of the first polarization and the optical path of the second polarization and converting the plurality of first polarizations and the plurality of second polarizations separated by the polarization splitter into linear parallel light, respectively; A polarization converting unit positioned on the optical path of the second polarization to convert the second polarization into the first polarization; A plurality of diffraction type optical modulators modulating incident light of a corresponding wavelength to generate and emit diffracted light having a plurality of diffraction orders; The first polarized light converted by the illumination lens system into linear parallel light is incident on the diffraction type optical modulator, and the second polarized light converted by the illumination lens into linear parallel light and changed into the first polarized light by the polarization converter. An incident field incident on the diffractive optical modulator so as to be symmetrical with a first polarization; A filter system for passing diffracted light of a desired order to each diffracted light emitted from the plurality of diffractive light modulators; And  And a projection system for condensing and scanning a plurality of diffracted light filtered by the filter system on a target object. The method of claim 1, The polarization separation unit, A polarization separator that separates incident light incident on the light sources having a plurality of wavelengths into first polarized light and second flat light; And And a condenser configured to condense the first and second polarizations of the plurality of wavelengths, respectively. The method of claim 1, The incident system is, The first polarized light converted by the illumination lens system into linear parallel light is incident on the diffraction type optical modulator, and the second polarized light converted by the illumination lens into linear parallel light and changed into the first polarized light by the polarization converter. And a beamsplitter incident on the diffraction optical modulator so as to be symmetrical to the first polarization. The method of claim 1, The filter system, A projection lens that separates diffracted light for each order so as to distinguish diffracted light having a plurality of diffraction orders emitted by the plurality of diffractive light modulators; And And a filter for passing diffracted light of a desired order in diffracted light for each order for each of the plurality of diffracted light separated by the projection lens.

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