KR20010039391A - Polarization converter and reflection type projector employing the polarization converter - Google Patents

Abstract

PURPOSE: A polarized beam converter and a reflection type projecting device are provided to improve the light efficiency by installing the polarized beam converter in a light passage. CONSTITUTION: A polarized beam converter comprises a polarized beam splitter(30) which allows an incident beam to be transmitted or reflected thereby dividing the incident beam into the first beam and the second beam. The polarized beam splitter(30) has a mirror surface(31) having the first perforation hole(33) for transmitting the incident beam. A phase delaying device(40) is provided to delay the phase of the second beam such that the second beam has the polarized component identical to the polarized component of the first beam. A focusing-reflection device(50) is provided to focus and reflect the second beam in such a manner that the second beam having the direction different from the first beam can be directed to the direction identical to the direction of the first beam. A dual focusing device(60) is provided to allow the first and second beams to have the same focus.

Description

Polarization converter and reflection type project apparatus employing the same {Polarization converter and reflection type projector employing the polarization converter}

The present invention provides a polarization converter that converts the incident unpolarized light into one polarized light and a reflective project in which the brightness of the light projected on the screen can be increased by using all of the unpolarized light emitted from the light source. Relates to a device.

In general, a project apparatus is an apparatus for providing an image by projecting an image generated by the image generating means onto a screen using a separate light source. This projector apparatus requires an optical member for specifying the polarization of incident light on the optical path between the light source and the image generating means by employing a transmissive or reflective liquid crystal display element or the like as the image generating means. The optical member may be a polarizing beam splitter 10 having a configuration as shown in FIG.

The polarizing beam splitter 10 reflects light of S-polarized light having a polarization direction parallel to the mirror surface 11 among incident unpolarized light P + S, and light of P polarization that is not parallel to the mirror surface 11. Has the property of transmitting. In the case where such a polarizing beam splitter 10 is employed, only the P-polarized light or the S-polarized light is used separately from the incident unpolarized light, and no other polarized light is used. There is a problem that the light loss occurs by the amount of light corresponding to the light.

On the other hand, in view of such a point in the prior art has been disclosed a polarization converter 20 as shown in FIG.

The disclosed polarizing transducer 20 includes a cylindrical lens array 21, a polarizing beam splitter 23, a reflecting member 25 and a half wave plate 27. The cylindrical lens array 21 is irradiated in parallel and focuses and diverges incident light having a rectangular cross section so as to be parallel light having a smaller cross-sectional area, so that incident light is lost when securing the installation space of the reflective member 25. Do not. A plurality of polarizing beam splitters 23 are provided, each of which is disposed to face the light exit surface of the cylindrical lens array 21, and splits incident light into first and second light according to a polarization component, and predetermined polarization. Has a mirror surface 23a that transmits the first light and reflects the second light of another polarization. The reflection member 25 is provided in plural in a position corresponding to the polarization beam splitter 23, and reflects the second light so that the second light is directed in parallel with the first light. The reflective member 25 is disposed in a space secured by the cylindrical lens array 21, that is, a space where no light does not enter through the polarizing beam splitter 23.

Looking at the operation of the polarization converter 20 as follows. P-polarized light is transmitted at the mirror surface 23a and incident S-polarized light is reflected. The reflected S-polarized light is reflected by the reflecting member 25 again, and proceeds in parallel with the P-polarized light. The S-polarized light is delayed by the half-wave plate while passing through the half-wave plate 27 and is emitted while the polarization direction is changed to light of P-polarized light. The polarization converter 20 has an advantage of converting irradiated unpolarized light into light of one polarization component.

Meanwhile, the polarization converter 20 configured as described above includes the cylindrical lens array 21, the plurality of polarizing beam splitters 23, the plurality of reflecting members 25, and the plurality of half wave plates 27. Since it is provided, there is a disadvantage that the configuration is complicated. In addition, there is a disadvantage in that optical alignment is difficult to allow the light traveling through the polarization converter 20 to proceed in parallel with each other.

Accordingly, the present invention has been made in view of the above-described problems, and the polarization converter and the optical path image is converted into incident light into a predetermined polarized light with little light loss, and the converted light travels through one focal point. The purpose of the present invention is to provide a reflective project apparatus that can be disposed in the device to increase the light efficiency.

1 is a schematic view showing a general polarizing beam splitter;

Figure 2 is a schematic diagram showing the optical arrangement of a conventional polarizer.

3 is a schematic view showing an optical arrangement of a polarization converter according to an embodiment of the present invention.

4 is a schematic view showing an optical arrangement of a reflective project device employing another polarization transducer in an embodiment of the present invention.

<Description of the code | symbol about the principal part of drawing>

30.Polarized beam splitter 31 ... mirror 33 ... first pass

40 Phase delay means 41 ... 1/4 wave plate 43 First reflector

50. Focusing means 51 ... Concave reflector 60 ... Dual focusing means

61. Focusing lens 63 ... Second reflecting member 64 ... Second passing hole

65 Convex reflecting surface 67 Third reflecting member 68 Concave reflecting surface

110 Light source 120 Uniform light source 130 Polarization converter

141, 143, 145 ... first to third polarizing beam splitters

152,154,156 First to third reflective liquid crystal display elements

160 ... color prism 170 ... projection lens unit

DM1 ... Dichroic mirror DM2 ... Dichroic mirror M1, M2, M3 ... reflective mirror

A polarization converter according to the present invention for achieving the above object has a mirror surface having a first through-hole formed to pass incident light in the center portion, the first light and the second light by transmitting or reflecting the incident light according to the polarization And polarized beam splitter for branching; Phase delay means for delaying a phase of the second light branched from the polarization beam splitter to be light having the same polarization component as the first light, and reflecting it back toward the polarization beam splitter; Focusing reflecting means for passing through the transmission hole toward the traveling direction of the first light by focusing and reflecting the second light traveling in a direction opposite to the traveling direction of the first light via the phase delay means and the polarizing beam splitter and; And bifocal means having different focal points for each of the first and second light incident in different forms so that the first and second light traveling in the same direction have the same focus. .

The present invention for achieving the above object, and a light source for generating and projecting light; A polarization converter for converting light emitted from the light source into light of one polarization component; Optical branch means for splitting light of one polarization transmitted through the polarization converter according to a wavelength region; Optical path converting means disposed on a traveling path of each of the light branched by the optical branch means to convert a traveling path of the light; Image generating means for generating an image from incident light of one polarization component via the optical path changing means; A color prism generated by the image generating means and selectively transmitting or reflecting light according to a wavelength so that light incident through the light path converting means is emitted in one direction; A projection lens unit which enlarges and transmits the light incident from the color prism toward the screen; In the reflective project device comprising, the polarization converter is provided with a mirror surface having a transmission hole formed to pass the incident light in the center, and transmits or reflects the incident light according to the polarized light to split the first light and the second light A polarizing beam splitter; Phase delay means for delaying a phase of the second light branched from the polarization beam splitter to be light having the same polarization component as the first light, and reflecting it back toward the polarization beam splitter; Focusing reflecting means for focusing the second light traveling in a direction opposite to the traveling direction of the first light via the phase delay means and the polarizing beam splitter so as to pass through the transmission hole in the traveling direction of the first light and; And bifocal means having different focal points for each of the first and second light incident in different forms so that the first and second light traveling in the same direction have the same focus. .

Hereinafter, a polarization converter and a reflective project device employing the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 3, a polarization converter according to an exemplary embodiment of the present invention transmits or reflects unpolarized incident light according to polarized light to split the polarized beam splitter 30 into first light I and second light II. And the direction of the first light I passing through the phase delay means 40 for delaying the phase of the second light II, the phase delay means 40 and the polarizing beam splitter 30. Focusing reflecting means 50 for focusing and reflecting the second light (II) proceeding in the opposite direction to the second direction, and the double focus to make the first and second light (I) (II) proceeding in the same direction to have the same focus It comprises a means (60).

The polarizing beam splitter 30 has a mirror surface 31 having a first transmission hole 33 formed to pass incident light in a central portion thereof. The mirror surface 31 transmits or reflects incident light according to polarized light, and splits the incident light into first light I of one polarization component and second light II of a different polarization component. Here, the reflected first light I is directed directly toward the dual focusing means 60. When parallel light is incident on the polarization beam splitter 30, the first light I reflected from the mirror surface 31 is directed toward the dual focusing means 60 while maintaining parallelism, and the mirror surface 31 is disposed. The second light II transmitted therethrough is directed to the phase delay means 40 while maintaining parallelism.

The phase delay means 40 delays the phase of the incident second light II to be the same polarized light as the first light I, and reflects it back toward the polarization beam splitter 30. The phase delay means 40 includes a quarter wave plate 41 for retarding the phase of incident light and a second light II transmitted through the polarization beam splitter 30 and the quarter wave plate 41. And a first reflecting member 43 for reflecting back toward the quarter wave plate 41 and the polarizing beam splitter 30. Here, the second light (II) reflected by the first reflecting member 43 passes through the quarter wave plate 41 again, so that the phase is delayed by 1/2 wavelength and the first light I and It becomes the light of the same polarization.

As such, the light incident on the polarization beam splitter 30 with the polarization changed is reflected on the rear surface of the mirror surface 31 and proceeds in the opposite direction to the first light reflected by the polarization beam splitter 30.

The focusing reflector 50 is a concave reflector 51 as shown, focusing and reflecting the second light (II) traveling in a direction opposite to the traveling direction of the first light (I) to the polarizing beam splitter ( To 30). The light reflected by the concave reflector 51 passes in the same direction as the first light I passing through the first transmission hole 33 of the polarization beam splitter 30 and reflected by the mirror surface 31. do.

The dual focusing means 60 is to ensure that the first light I incident in parallel and the second light II incident on diverging have the same focus, and the focusing lens 61, the second and third reflecting members are the same. And (63) (67).

The focusing lens 61 focuses and transmits the first light I reflected from the mirror surface 31 and the second light II transmitted through the first through hole 33. I) is to be focused light, and the second light (II) is to be parallel light. To this end, it is preferable that the front focusing distance ffl and the rear focusing distance bfl of the focusing lens 61 have the same distance. Here, the front focus of the focusing lens 61 is located in the first through hole 33.

The second reflecting member 63 has a second transmission hole 64 for transmitting focused light and a convex reflecting surface 65 for emitting light incident in parallel. The second transmission hole 64 transmits the first light focused by the focusing lens 61 and the second light focused and reflected by the third reflecting member 67.

The third reflecting member 67 is disposed around the focusing lens 61, and focuses and reflects the second light reflected from the convex reflecting surface 65 to travel toward the second transmission hole 64. It has a concave reflecting surface 68.

Accordingly, the polarization converter configured as described above converts the incident unpolarized light into one polarized light with little light loss, and causes the converted light to travel in one traveling path. In addition, the light traveling in one traveling path is a light traveling through one point, that is, the rear focus of the focusing lens, through the double focusing means.

Referring to FIG. 4, a reflective project device employing a polarization converter according to an embodiment of the present invention includes a light source 110 and a polarization converter for converting light emitted from the light source 110 into light of one polarization component ( 130), an optical branching means for branching incident light along a wavelength region, an optical path converting means for converting a traveling path of the incident light, an image generating means, a color prism, and a projection lens unit for magnifying and projecting the generated image; .

The light source 110 includes a lamp 111 for generating light and a reflector 113 for reflecting the light emitted from the lamp 111 and guiding a path of the light. The reflector 113 may be an ellipsoidal mirror having the position of the lamp 111 as one focal point and the point where the light is focused as another focal point, or the lamp 111 having the position of the lamp 111 as one focal point. The light emitted and reflected by the reflector 113 may be a parabolic mirror in which parallel light is formed.

The polarization converter 130 is a polarizing beam splitter 30 for transmitting or reflecting the incident light according to the polarized light to split the first light and the second light, phase delay means 40 for delaying the phase of the second light, Focusing reflecting means 50 for focusing and reflecting the second light traveling in a direction opposite to the traveling direction of the first light via the phase delay means 40 and the polarizing beam splitter 30, And a dual focusing means 60 which allows the first and second lights to have the same focus. Since the configuration of the polarization converter 130 is substantially the same as that described with reference to FIG. 3, a detailed description thereof will be omitted.

Here, it is preferable that the uniform light illumination means 120 is provided on the optical path between the light source 110 and the polarization converter 130 so that the light irradiated from the light source 110 is uniform light. One embodiment of the uniform light luminaire 120 may include a pair of fly-eye lenses 121, 125 having a configuration as shown. In addition, the uniform light illuminator 120 is a rectangular parallelepiped glass rod (not shown) that diffuses the incident light to be uniform light and converts the cross-sectional shape of the light emitted from the lamp 111 from circular to square. It may include.

In addition, it is preferable to further include a band pass filter 127 on the optical path between the light source 110 and the polarization converter 130 to transmit only the light in the visible wavelength range of the light emitted from the light source 110. That is, the band filter 127 blocks infrared and ultraviolet light.

The optical branching means converts the advancing path of light for each color by selectively transmitting or reflecting incident light of one polarization component via the polarization converter 130 according to the wavelength region. That is, the incident white polarized light splits into red, blue and green light.

To this end, the optical diverging means includes a first dichroic mirror DM1 for dividing incident light along a wavelength region and a second dichroic mirror DM2 for dividing light diverged from the first dichroic mirror DM1 again according to a wavelength region. It is configured to include.

For example, the first dichroic mirror DM1 is manufactured by a dielectric coating and is disposed on an optical path between the polarization converter 130 and the optical path converting means, and the blue light B of the incident light R + G + B. Reflects and transmits red and green light (R + G). The light R + G transmitted through the first dichroic mirror DM1 is reflected by the reflective mirror M1 and the path is converted, and the light B reflected by the first dichroic mirror DM1 is the reflective mirror M2. , Reflected at M3) and the path is transformed. The second dichroic mirror DM2 is disposed on a path of the light R + G reflected by the reflective mirror M1 to branch the incident red light R and green light G. That is, the red light R is reflected and the green light G is transmitted.

The optical path converting means is disposed to face each of the three incidence planes of the color prism, and transmits light of one polarized light which is branched from the optical splitting means DM1 and DM2, and is reflected by the image generating means. The converted light includes first to third polarized beam splitters 141, 143, 145 that are adapted to reflect.

The image generating means may include first to third reflective liquid crystal display elements 152 for generating and reflecting an image from respective light incident through the first to third polarization beam splitters 141, 143, and 145. 154, 156). In addition, the image generating means may block the light of another polarization component that may be included in the light converted by the polarization converter 130, the first to third reflective liquid crystal display elements 152, 154, 156 It is preferable to further include the first to third polarizers 151, 153, and 155 disposed on the light paths respectively incident. Each of the first to third reflective liquid crystal display elements 61, 63, and 65 is formed of a ferroelectric liquid crystal display device (hereinafter referred to as a FLCD; Ferroelectric Liquid Crystal Display). The FLCD has a two-dimensional array structure and has a plurality of pixels each independently driven, and selectively driven for each pixel. Accordingly, the light reflected from the pixel on which the image is not formed converts the polarization direction in a direction different from the polarization direction of the incident light.

The color prism 160 has three entrance faces and one exit face. Each of the three incidence planes faces the first to third polarization beam splitters 141, 143, and 145, and each of the three incidence planes faces the advancing path of the incident light such that light incident through the polarization beam splitters is directed toward the one exit surface. Convert. To this end, the color prism 160 has a mirror surface that selectively transmits or reflects light depending on the wavelength. The mirror surface is coated to transmit and reflect along the wavelength region.

The projection lens unit 170 is disposed between the color prism 160 and a screen (not shown) to enlarge and project the light incident from the color prism 160 toward the screen.

As described above, the polarizer according to the embodiment of the present invention configured has the advantage that the light efficiency can be increased by converting the incident light into the light of the predetermined polarization with little light loss and allowing the converted light to proceed through one focal point. There is this.

In addition, the reflective project device employing the polarization converter on the optical path can significantly increase the light efficiency by converting the light irradiated from the light source into light of one polarization with little light loss and forming the image.

Claims (8)

A polarizing beam splitter having a mirror surface having a first through hole formed to allow incident light to pass through the central part, and transmitting or reflecting incident light according to polarized light to split the incident light into first and second light; Phase delay means for delaying a phase of the second light branched from the polarization beam splitter to be light having the same polarization component as the first light, and reflecting it back toward the polarization beam splitter; Focusing reflecting means for focusing the second light traveling in a direction opposite to the traveling direction of the first light via the phase delay means and the polarizing beam splitter so as to pass through the transmission hole in the traveling direction of the first light and, And bifocal means having different focal points for each of the first and second light incident in different forms so that the first and second light traveling in the same direction have the same focal point. Polarization transducer. The method of claim 1, wherein the phase delay means, A first reflection member for re-reflecting the second light branched from the polarization beam splitter toward the polarization beam splitter, and disposed on an optical path between the polarization beam splitter and the first reflection member to retard the phase of the second light; And a quarter-wave plate configured to be light having the same polarization component as the first light. The method of claim 1, wherein the focusing reflecting means, And a concave reflector configured to focus and reflect the second light incident in parallel. According to any one of claims 1 to 3, wherein the double focus means, A focusing lens for focusing the first and second light beams so that the incident first light beams are focused light beams and the second light beams being parallel light beams; A second reflecting member having a second transmission hole for transmitting the focused first light and having a convex reflecting surface for diverging and reflecting the incident second light; And a third reflecting member disposed around the focusing lens and having a concave reflecting surface such that the second light reflected from the convex reflecting surface is incident toward the second transmission hole. A light source for generating and projecting light; A polarization converter for converting light emitted from the light source into light of one polarization component; Optical branch means for splitting light of one polarization transmitted through the polarization converter according to a wavelength region; Optical path converting means disposed on a traveling path of each of the light branched by the optical branch means to convert a traveling path of the light; Image generating means for generating an image from incident light of one polarization component via the optical path changing means; A color prism generated by the image generating means and selectively transmitting or reflecting light according to a wavelength so that light incident through the light path converting means is emitted in one direction; A projection lens unit which enlarges and transmits the light incident from the color prism toward the screen; In the reflective project device comprising: The polarization converter, A polarizing beam splitter having a mirror surface having a transmission hole formed to pass incident light in a central portion thereof, for transmitting or reflecting the incident light according to polarization to split the incident light into first and second light; Phase delay means for delaying a phase of the second light branched from the polarization beam splitter to be light having the same polarization component as the first light, and reflecting it back toward the polarization beam splitter; Focusing reflecting means for focusing the second light traveling in a direction opposite to the traveling direction of the first light via the phase delay means and the polarizing beam splitter so as to pass through the transmission hole in the traveling direction of the first light and; And a dual focusing means for different focusing for each of the first and second light incident in different forms so that the first and second light traveling in the same direction have the same focus. Mold project device. The method of claim 5, wherein the phase delay means, A first reflection member for re-reflecting the second light branched from the polarization beam splitter toward the polarization beam splitter, and disposed on an optical path between the polarization beam splitter and the first reflection member to retard the phase of the second light; And a quarter wave plate configured to be light having the same polarization component as the first light. The method of claim 5, wherein the focusing reflecting means, And a concave reflector configured to focus and reflect the second light incident in parallel. The method of any one of claims 5 to 7, wherein the double focus means, A focusing lens for focusing the first and second light beams so that the incident first light beams are focused light beams and the second light beams being parallel light beams; A second reflecting member having a second transmission hole for transmitting the focused first light and having a convex reflecting surface for diverging and reflecting the incident second light; And a third reflecting member disposed around the focusing lens and having a concave reflecting surface such that the second light reflected from the convex reflecting surface is incident toward the second transmission hole. .