KR20040020335A - optical system using Polarization Converting and Color Recapturing Integrator and color switch - Google Patents

Abstract

PURPOSE: An optical system provided with a polarization converting and color recapturing(PCCR) integrator and a color switch is provided to allow a P/S convert and a color recapturing at the same time while removing the optical loss generated by the integrator and the color wheel during the recapturing process. CONSTITUTION: An optical system provided with a polarization converting and color recapturing(PCCR) integrator(200) and a color switch(400) includes a light source, a PCCR integrator(200) and a color switch. The light source is provided with a light source lamp and a reflector. The PCCR integrator(200) P/S divides the irregular polarized light outputted from the light source and transmits a specific polarized light. The PCCR integrator(200) maintains a polarized direction after transmitting the specific polarized light again and changing the phase of the remaining polarized light by the reflection of thereof. And, the color switch(400) placed adjacent to the output surface of the PCCR integrator(200) divides, transmits and reflects the color of the light beam.

Description

Optical system using Polarization Converting and Color Recapturing Integrator and color switch}

The present invention relates to an optical system applied to a projection TV or a projection monitor, and more particularly, to an integrator for polarization conversion and color recapturing, and a color scroll device and an optical system using the integrator.

An optical system applied to a conventional projection TV or monitor is a polarized light beam having a kind of polarization direction in which a polarized light emitted from a light source lamp largely matches an irregular light source (hereinafter referred to as an irregular polarized light beam). A polarization converting unit for converting, a color recapturing unit for performing color recapturing of the polarized light beam radiated with one kind of polarization direction in the polarization illuminating device, and for color scrolling the color configured in the reflective or transmissive LCD It consists of a color scroll (color scroll).

1 is a diagram illustrating a detailed configuration of a polarization converting unit in a general optical system.

As shown in FIG. 1, the polarization converting unit 40 includes a light source unit 10 including a light source lamp 11 and a parabolic reflector 12, a first optical element 30, and a second optical element 40. It is composed of

The first optical element 30 is formed by arranging a plurality of beam splitting lenses 31 having a rectangular shape in a matrix shape, and the second optical element 40 includes a condenser lens array 41, The light shielding plate 44, the polarization separation unit array 43, the selective retardation plate 45, and the coupling lens 46 are composed of a composite composed of one.

The polarization converting unit configured as described above is divided into a plurality of intermediate light beams by the light beam splitting lens 31. The irregularly polarized light beams incident from the light source unit 10 into the first optical element 30 are formed.

Subsequently, the divided plurality of intermediate light beams are spatially separated from the P-polarized light beam and the S-polarized light beam by the polarization separation unit array 43, and then the polarization directions spatially separated by the selective retardation plate 45 are combined into one. Match. Then, the matched polarized light flux is guided to the illumination region 50 through the coupling lens 46.

2A and 2B are diagrams showing the detailed configuration of the color separation and synthesis unit for general separation and synthesis.

2A is a view showing a transmissive LCD, and the light beam emitted through the illumination region 50 first transmits blue and green light and reflects red light in the red light reflecting mirror 72 which is a color light separating means. The reflected red light is then reflected by the reflection mirror 71 at the next stage to reach the liquid crystal part 61 for red light.

On the other hand, the blue light and green light transmitted from the red light reflecting mirror 72 is again reflected by the green light reflecting mirror 73, which is a color light separating means, and the blue light is transmitted.

Subsequently, the reflected green light reaches the green light liquid crystal part 62, and the blue light transmitted by the green light reflecting mirror 73 is reflected by the reflecting mirror 74 positioned at the next stage and reflected on the blue light liquid crystal part 63. To reach.

The three liquid crystal units 61, 62, and 63 modulate the respective color lights to include image information corresponding to each color light, and then apply the modulated color light to the cross dichroic prism 60 serving as color light synthesizing means. After being incident, the cross dichroic prism 60 combines the respective modulated light beams to form a color image, and is then enlarged and projected onto the screen 80 by the projection lens 70 which is a projection optical system to form a projection image. do.

2B is a view showing a reflective LCD, in which the luminous flux emitted through the illumination region 50 first transmits red and green light and reflects blue light in the blue light reflecting mirror 75 which is a color light separating means.

Subsequently, the reflected blue light is reflected by the reflecting mirror 77 located at the next stage, is reflected by the red light PBS 94 and reaches the red light liquid crystal part 95. After the phase is inverted by 90 degrees, the red light PBS is again inverted. It penetrates 94 and enters the cross dichroic prism 60.

On the other hand, the red light and green light transmitted from the blue light reflecting mirror 75 is again reflected by the green light reflecting mirror 76, which is a color light separating means, the red light is transmitted.

Subsequently, the reflected green light is reflected by the green light PBS 92 to reach the green light liquid crystal part 93, and after the phase is inverted by 90 degrees, passes through the green light PBS 92 again to cross the dichroic prism Incident).

The red light transmitted from the green light reflecting mirror 76 is reflected by the red light PBS 90 and reaches the red light liquid crystal part 91. After the phase is reversed by 90 degrees, the red light PBS 90 is again inverted. It penetrates and enters the cross dichroic prism 60.

The cross dichroic prism 60 combines each of the incident modulated light beams to form a color image, and is then enlarged and projected onto the screen 80 by the projection lens 70 as a projection optical system to form a projection image. do.

The optical system configured as described above can be classified into a single plate type, a two plate type, and a three plate type depending on how many liquid crystal units used as display devices are used.

The optical system shown in FIG. 2A and FIG. 2B has shown the 3-plate optical system as an Example.

However, such a three-plate optical system has three major problems.

The first is complicated because the number of optical components is too large and includes not only an illumination system but also a relay system to compensate for optical path differences, and the size of the optical system is also large.

Second, the color purity of red is reduced due to the lack of red light output from the lamp, which causes the ability to express color, that is, the width of the color gamut, becomes narrow. Have

Lastly, the third use of display devices, which are major components of the optical system, raises costs and alignment problems of R, G, and B panels.

In order to solve this problem, a two-plate or single-plate optical system has been recently used. However, the two-plate or single-plate optical system uses a plurality of colors in one liquid crystal unit, unlike a three-plate type that spatially separates and synthesizes colors. The light having the incident light is separated and synthesized in time through a color drum, a color wheel, or a color switch, which is a color scroll device.

As a result, there is a problem that the amount of light is insufficient compared to the conventional three-plate optical system.

That is, if green light or blue light is emitted to an area of the color scrolling device that transmits only red light, light other than red light is absorbed or reflected by the color scrolling device and is lost, so that the amount of light transmitted through the color scrolling device is reduced. do.

In addition, the existing color scrolling device uses a color wheel that forms a spiral color cell as shown in FIG. 5 for color recapturing. Such a spiral color wheel is difficult to manufacture. In addition, since the color bar has a circular arc shape on the surface of a DMD, a reflective LCD, or a transmissive LCD, the color bar movement is not linear with time, resulting in a decrease in light efficiency. .

Therefore, the present invention has been made to solve the above problems, the optical component structure and principle of the integrator that can simultaneously perform color recapturing at the same time with the polarization conversion in the conventional single-plate or two-plate optical system The purpose is to provide.

Another object of the present invention is to display an LCoS or LCD that uses polarized light as well as DMD, which is a display device that does not use polarized light by output polarization maintaining one polarization direction during polarization conversion and color recapturing. This is to enable color recapturing in the optical system used.

Another object of the present invention is to increase the amount of light than conventional, when using a display element using polarized light, such as LCoS or LCD, when configuring a single-plate or two-plate optical system.

Another object of the present invention is to provide a method for simultaneously performing polarization conversion, color recapturing, and color scrolling using the integrator proposed in the present invention.

Still another object of the present invention is to implement an optical system that is smaller in size and lower in cost than conventional optical systems by implementing a simpler structure than conventional optical systems.

1 is a view showing a detailed configuration of the polarization converter in a general optical system

2A and 2B are diagrams showing the configuration of a three-plate optical system of a general transmissive LCD and a reflective LCD.

3 is a view showing a polarization converting unit having a PCCR integrator according to the present invention;

4 shows light loss caused by the distance between the PCCR integrator and the color wheel.

5 is a view showing the configuration of a spiral color wheel which is a general color scroll unit;

6 is a view showing a polarization converting unit having a PCCR integrator and a color switch according to the present invention;

7 illustrates the structure of a color switch in an optical system having a PCCR integrator and a color switch according to the present invention;

8 shows a red cell of a color switch in an optical system having a PCCR integrator and a color switch according to the present invention;

9 is a view showing a phase modulation process of light by the color switch according to the present invention

FIG. 10 is a view illustrating a process in which light modulated by a color switch according to the present invention is reflected and transmitted in a reflective polarizer; FIG.

11 is a view showing the movement of color bars with time in an optical system having a PCCR integrator and a color switch according to the present invention;

* Explanation of symbols for main parts of the drawings

100: light source unit 110: light source lamp

120: parabolic reflector 200: PCCR integrator

210: phase difference plate 211: opening

220: reflective polarizer 230: reflective surface

300: color scroll unit 400: color switch

410: color selection unit 420: LC cell

Features of the optical system having a PCCR integrator and a color switch according to the present invention for achieving the above object is to separate the P / S light source unit consisting of a light source lamp and a parabolic reflector, and the irregular polarized light beam emitted from the light source unit and a specific polarized light beam Is transmitted through and the remaining polarized light flux changes its phase through reflection and then retransmitted to maintain one polarization direction, and a color that separates and transmits and reflects the color of the light beam that comes into contact with the exit surface of the PCCR integrator It is configured to include a switch.

In this case, it is preferable that reflective polarizing plates are formed on both side surfaces of the color switch.

The color switch is preferably configured by bonding a red cell to assist the phase of red light, a green cell to modulate the phase of green light, and a blue cell to modulate the phase of blue light.

At this time, each cell is a polarized light of a predetermined color by the two color selector (ColorSelect) serving as a λ / 4 plate only for the selection light and the electrical signal which is bonded between the color selector and input from the outside It is preferable to include an LC (Liquid crystal) cell for converting.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of an optical system having a PCCR integrator and a color switch according to the present invention will be described with reference to the accompanying drawings.

3 is a diagram illustrating a polarization converting unit having a polarization converting and color recapturing (PCCR) integrator according to the present invention.

Referring to FIG. 3, the light source unit 100 including the light source lamp 110 and the parabolic reflector 120 and the irregular polarized light beams emitted from the light source unit 100 are separated by P / S, and the specific polarized light beams are transmitted and the remaining polarized light beams are transmitted. The PCCR integrator 200 maintains one polarization direction after changing the phase through the reflection, and the color scroll unit 300 separates and transmits and reflects the color of the light beam emitted from the PCCR integrator 200. It consists of.

In this case, the PCCR integrator 200 is formed on a predetermined path including a small opening 211 through which light having an irregular polarization direction is incident, a reflection surface 230 through which the light is reflected, and an exit surface of the incident light. And a reflection polarizing plate 220 which is separated into a P polarization light beam and an S polarization light beam to reflect or transmit, and formed in the predetermined path facing the reflective polarization plate 220 to reflect the light reflected from the reflection polarization plate 220. It is composed of a phase difference plate 210 for converting the phase by 90 degrees.

In more detail, polarized light 240 having an irregular polarization direction is incident through the small opening 211, and the light is passed through the S-polarized light beam 250 by the reflective polarizer 220, and the P-polarized light beam ( 260 is reflected. This may reflect the S-polarized light beam and pass the P-polarized light beam according to the characteristics of the reflective polarizing plate.

In addition, the reflected P-polarized light beam 260 is incident on the reflection surface 230 positioned on a predetermined path surface, or is incident on the phase difference plate 210 positioned directly at the front end, and the phase difference plate 210 is incident on P-polarized light. The phase of the light beam is converted by 90 degrees to the S-polarized light beam 270 and reflected.

The reflected light beam 270 is incident to the reflective polarizer 220 and then passed through.

Thus, the reflective polarizer 220 performs a role of a P / S converter that finally makes the light emitted through the PCCR integrator 200 into an S-wave to perform polarization conversion using an existing FEL and PBS array. It has a simpler structure and lowers the price of the optical system.

However, in the case of color scrolling using the color wheel 300, light loss occurs due to the distance between the integrator 200 and the color wheel 300 as shown in FIG. 4.

In order to solve this problem, the present invention proposes the following method as a method of color scrolling using a simple structure to eliminate such loss of light.

6 is a diagram illustrating a polarization conversion unit having a PCCR integrator and a color switch capable of polarization conversion and color recapture according to the present invention.

As shown in FIG. 6, the PCCR integrator 200 includes a color switch 400 that separates and transmits and reflects a color of a light beam incident upon contact with the PCCR integrator 200.

At this time, both side surfaces of the color switch 400 is a reflective polarizer 220 is formed.

Since the structure of the PCCR integrator 200 is the same as described above, the description thereof will be omitted.

In addition, the color switch 400 has a structure in which three cells, a red cell, a green cell, and a blue cell, are bonded to each other as illustrated in FIG. 7.

Each cell converts polarized light of a predetermined color by two color selectors serving as a λ / 4 plate only for selective light and an electrical signal bonded and input between the color selectors. It consists of an LC (Liquid crystal) cell.

8 illustrates a red cell of a color switch in an optical system having a PCCR integrator and a color switch according to the present invention.

As shown in Fig. 8, the structure of the red cells in the color switch is a color selector for red (410), which is a filter serving as a λ / 4 plate only for red light, and a red for switching red canal. It consists of an LC cell 420 and the red color selection part 410 again.

In this case, as the electrical signal input to the LC cell 420 is turned on or off, polarization of red light is switched in the red cell.

In this way, a color switch is formed by bonding a red cell to assist the phase of red light, a green cell to modulate the phase of green light, and a blue cell to modulate the phase of blue light.

A phase modulation process of light by the color selector 410 and the LC cell 420 in the red cell may be illustrated as shown in FIG. 9.

As shown in Fig. 9 (a), if the phase of incident light has a value of all zero degrees, after the first red color selection unit, only the phase of red light has a value of 45 degrees as shown in Fig. 9 (b).

When the modulated red light and the unmodulated green and blue light pass through the next red LC cell, the phase of the red light is modulated by 90 degrees or not according to the operation state of the LC cell.

If the LC cell is not modulated as shown in Fig. 9 (c), only the red light is modulated by 45 degrees by the red color selection unit at the back, and finally, as shown in Fig. 9 (d), the red light is 90 degrees as compared with green or blue. It is modulated and output.

If the phase of the red light in the LC cell is modulated as shown in FIG. 9 (e), only the red light is modulated by 45 degrees again by the red color selection unit at the back, and finally, as shown in FIG. And B are all in phase.

In this way, as the LC cell inputs and does not input a signal, an output terminal can modulate a specific color phase.

The color of the R, G, and B may be expressed in the display device by using the reflective polarizer 220 which modulates a phase of a specific color according to the signal and transmits or reflects the modulated light as shown in FIG. 10.

In addition, by forming an electrode as shown in FIG. 11 in the LC cell, color scrolling is possible in the display device by moving color bars of R, G, and B over time.

In this manner, polarization conversion, color scrolling, and color recapturing are possible in a simple structure, and the recapturing efficiency may increase because there is no gap between the integrator and the color switch performing color scrolling.

In addition, since the boundary between each color of the color switch, which is a color scroll structure, is composed of lines, it is possible to minimize the light loss due to the boundary surface, and the structure of the optical system is simplified.

The optical system having the PCCR integrator and the color switch according to the present invention as described above has the following effects.

First, the integrator proposed in the present invention enables P / S conversion and color recapturing at the same time according to its structure, and there is no light loss that can be caused by the gap between the integrator and the color wheel during the color recapturing process. .

Second, by not using a color wheel with spiral color cells, but by using a color switch as a color scrolling device, the shape of the color bars in the panel remains rectangular, and the scroll direction of the color bars is also linear. It has the advantage of minimizing light loss.

Third, in the case of a conventional color wheel or a rotating prism, a motor is used, whereas in the present invention, color scrolling is performed using an electrical signal to reduce mechanical vibration and noise. In addition, it has a simple structure than the conventional P / S converter, color recapturing system, color scrolling system has the advantage of reducing the cost and light weight of the optical system.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (4)

A light source unit comprising a light source lamp and a parabolic reflector, A PCCR integrator that separates the irregular polarized light beams emitted from the light source unit by P / S, transmits a specific polarized light beam, and transmits the remaining polarized light beams by changing the phase through reflection and then retransmitting them to maintain one polarization direction; An optical system having a PCCR integrator and a color switch, characterized in that it comprises a color switch for separating and transmitting and reflecting the color of the light beam that is in contact with the exit surface of the PCCR integrator. The method of claim 1, An optical system having a PCCR integrator and a color switch, wherein reflective polarizers are formed on both sides of the color switch. The method of claim 1, The color switch includes an optical system having a PCCR integrator and a color switch, wherein a red cell assisting the phase of the red light, a green cell modulating the phase of the green light, and a blue cell modulating the phase of the blue light are bonded to each other. . The method of claim 3, wherein Each cell includes two color selectors serving as? / 4 plates for only selective light; And an LC (Liquid Crystal) cell bonded between the color selectors and converting polarized light of a predetermined color by an electrical signal input from the outside.