KR100335437B1 - Reflection type projector - Google Patents

Abstract

Disclosed is a reflective project device capable of increasing the brightness of light emitted from a light source and projected onto a screen.

This disclosed apparatus includes 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; A first half relay lens system disposed between the light source and the polarization transducer to make incident light approximately parallel light; Optical branch means for branching light of one polarized light transmitted through the polarization converter according to the wavelength region; Optical path converting means disposed on a traveling path of each of the light branched by the optical branch means, and converting the traveling path of the light; A rear half relay lens system arranged in a path between the optical branch means and the optical path changing means; 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 the 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; It is characterized by including.

Description

Reflective Projector {Reflection type projector}

The present invention relates to a reflective project apparatus using reflective image generating means, and more particularly, to a reflective project apparatus that can increase the brightness of light projected on a screen by using all of unpolarized light emitted from a light source. will be.

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 is classified into a transmission type and a reflection type according to the form of the image generating means described above.

Applicant has applied two 'reflective project devices' using a critical angle prism to enhance the utilization efficiency of light irradiated from a light source (Korean Patent Application No. 132525, filing date; April 9, 1997, inventor; Choi Soon-Chul), (Korean Patent Application No. 1322, Application Date; April 10, 1997, Inventor; Choi Soon-Chul) in Korea.

The proposed reflective project device has the advantage that the optical arrangement can be compacted by changing the optical path through the critical angle prism, but only the P-polarized or S-polarized light is separated by the polarizer out of the unpolarized light emitted from the light source. By using it for formation, there exists a problem that light loss generate | occur | produces by the light quantity corresponding to the light of one polarization component which is not used.

Accordingly, the present invention has been made in view of the above-described problems, and the reflection type project apparatus can improve the light efficiency by converting the incident light into the light of predetermined polarization with little light loss and entering the reflection type image forming means. The purpose is to provide.

1 is a schematic view showing an optical arrangement of a reflective project apparatus according to an embodiment of the present invention.

FIG. 2 is a view showing optical arrangement of optical elements including first and second half relay lens systems according to a line alignment between reflective liquid crystal display elements in a window of the reflective project apparatus shown in FIG.

FIG. 3 is a view showing an optical arrangement of the front relay lens system of the reflective project device shown in FIG. 1; FIG.

Figure 4 is an exploded perspective view showing the optical arrangement of the polarization converter according to the present invention.

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

FIG. 6 is a view for explaining the operation of the polarizer shown in FIG.

FIG. 7 is a view showing an optical arrangement of a rear relay lens system of the reflective projector device shown in FIG. 1; FIG.

<Explanation of symbols for main parts of the drawings>

10 ... light source 20 ... band filter 31 ... glass rod

33 Windows 40 Polarizer 41 Cylindrical Lens Array

43.Polarizing beam splitter 45 ... Reflector 47 Phase delay plate

51 ... first critical prism 53 ... second critical prism 55 ... third critical prism

60 ... Image generating means 61 ... First reflective liquid crystal display element

62 first polarizer 63 second reflective LCD

64 ... 2nd Polarizer 65 ... 3rd Reflection LCD

66 3rd Polarizer 70 Color Prism 80 Projection Lens Unit

Ⅰ ... Rear relay lens system Ⅱ ... Rear relay lens system

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

In order to achieve the above object, a reflective project device according to the present invention comprises: 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; A first half relay lens system disposed between the light source and the polarization transducer to make incident light approximately parallel light; 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; A rear half relay lens system arranged in a path between the optical branch means and the optical path changing means; Image generating means for generating an image from incident light of one polarization component via the optical path changing means; A color prism selectively transmitting or reflecting light according to a wavelength such that light generated by the image generating means and incident upon 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; It is characterized by including.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the reflective project apparatus according to the present invention.

Referring to FIG. 1, the reflective project device according to the present invention includes a light source 10, a polarization converter 40 for converting unpolarized light emitted from the light source 10 into light of one polarization component, and incident light. The first half relay lens system (I) to make substantially parallel light, the optical branch means for splitting incident light along the wavelength region, the optical path converting means for converting the traveling path of each branched light, and the second half relay lens system And image generating means 60 for generating an image from incident light of one polarization component via the optical path changing means, and a color prism 70 for projecting the image generated by the image generating means 60 in one path. And a projection lens unit 80 which enlarges and transmits the light incident from the color prism 70 side.

The light source 10 includes a lamp 11 for generating light, and a reflector 13 for reflecting the light emitted from the lamp 11 and guiding a progress path thereof.

The reflector 13 is an ellipsoidal mirror with the position of the lamp 11 as one focal point, and the point where the light is focused as another focal point, or the lamp 11 with the position of the lamp 11 as one focal point. It may be a parabolic mirror emitted from the light reflected by the reflector 13 to be parallel light.

On the optical path between the light source 10 and the first half relay lens system I, the light irradiated from the light source 10 is diffused to be uniform light, and the cross-sectional shape of the light irradiated from the lamp 11 is square in a circular shape. It is preferable to further include the glass rod 31 of the rectangular parallelepiped shape converted into a shape. The glass rod 31 has an incidence plane and an exit plane perpendicular to the optical path, and the aspect ratio of the glass rod 31 is proportional to the aspect ratio of the image forming means 60. do. Here, it is preferable that the exit surface of the glass rod 31 is equipped with the glass rod 31 and a window 33 is provided on the exit surface to prevent dust from entering. As described above, when the glass rod 31 is employed, the reflector 13 is an ellipsoid.

The apparatus may further include a band filter 20 disposed on an optical path between the light source 10 and the first half relay lens system I to transmit only light in a visible wavelength range among the light emitted from the light source 10. It is desirable to. That is, the band pass filter 20 blocks infrared and ultraviolet light.

The first half relay lens system I focuses the diverging light emitted through the exit surface of the glass rod 31 so that approximately parallel light is incident on the polarization converter 40. To this end, the first half relay lens system I has a positive power and a focal length, as shown in FIGS. 2 and 3. The first lens group (L1, L2) having a positive, and has a positive power and the focal length with the polarization converter 40 And second lens groups L3 and L4 having a. Here, the first lens group L1 and L2 and the second lens group L3 and L4 are focal lengths. And Are arranged to coincide with each other so that the light transmitted through the second lens groups L3 and L4 becomes substantially parallel light. The first lens group is composed of two lenses L1 and L2, and the second lens group is also composed of two lenses L3 and L4.

Here, the width of the light incident on the first half of the relay lens system ( The width of the emitted light for Scaling factor Preferably satisfies Equation 1 below.

Table 1 shows examples of curvature radii, lens thicknesses, and spacings, refractive indices, and dispersions of the lenses and the windows 33 and the polarization converter 40 constituting the first half relay lens system I.

The polarization converter 40 is an optical member that converts unpolarized light emitted from the light source 10 into light of one polarization component.

4 to 6, the polarization converter 40 includes a cylindrical lens array 41, a polarization beam splitter 43, a reflection member 45, and / 2 phase delay plate 47 is configured. The cylindrical lens array 41 is irradiated in parallel by the first half relay lens system (I) and focuses and diverges incident light having a rectangular cross section so that the cross-sectional area becomes parallel light. The cylindrical lens array 41 is provided to prevent light loss of incident light when securing the installation space of the reflective member 45. The polarizing beam splitter 43 is provided in plural, each of which is disposed to face the light exit surface of the cylindrical lens array 41, and splits incident light into first and second light according to a polarization component, and polarizes a predetermined polarization. Has a mirror surface 43a that transmits the first light and reflects the second light of another polarization. The reflective member 45 has a plurality of reflection surfaces 45a provided at a position corresponding to the polarization beam splitter 43 and reflects the second light in a direction parallel to the first light. . The reflecting member 45 is disposed in a space secured by the cylindrical lens array 41, that is, in a space where light that does not pass through the polarizing beam splitter 43 does not enter.

Looking at the operation of the polarization converter 40 as follows. As illustrated in FIG. 6, incident light of unpolarized light P + S is split from the mirror surface 43a of the polarization beam splitter 43 into the first light of P polarization and the second light of S polarization. The second light of S-polarized light reflected from the mirror surface 43a is reflected by the reflective surface 45a and travels in a direction parallel to the first light. This second light Phase is transmitted while passing through the / 2 phase delay plate 47. Delayed by, the polarization direction is emitted with the P-polarized light changing.

Therefore, the unpolarized light irradiated from the light source 10 passes through the polarization converter 40 and is converted into light of one polarization component with little loss of light.

The optical branching means converts the advancing path of light for each color by selectively transmitting or reflecting the incident light 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 40 and the optical path changing means to reflect blue light of incident light and transmit red and green light. . The light transmitted through the first dichroic mirror DM1 is reflected by the reflecting mirror M1 and the path is converted, and the light reflected by the first dichroic mirror DM1 is reflected by the reflecting mirrors M2 and M3. Is converted. The second dichroic mirror DM2 is disposed on a path of the light reflected by the reflective mirror M1 to branch the incident red and green light. That is, red light is reflected and green light is transmitted.

1, 2 and 7, the latter half relay lens system Is disposed between the first dichroic mirror DM1 and the image generating means 60 to allow incident light to converge on the image generating means 60. The second half relay lens system Has a positive power and the focal length The third lens group L5 and L6 having a positive power and a focal length Fourth lens group L7 with a positive power and focal length It includes a fifth lens group (L8) having a. Here, the third lens groups L5 and L6 and the fifth lens group L7 may be focal lengths. And Are arranged to coincide with each other. The third lens group is composed of two lenses L5 and L6, and each of the fourth and fifth lens groups is composed of one lens L7 and L8.

Here, the second half relay lens system The width of light incident on The width of the emitted light for Scaling factor Preferably satisfies Equation 2 below.

Table 2 shows an example of curvature radius, lens thickness and spacing, refractive index, and dispersion for each lens, the optical path converting means, and the image generating means constituting the above-described rear relay lens system.

Table 2 shows the light beam starting position of FIG. 7 where the aperture (not shown) is located. The critical angle prism, polarizer, and FLCD will be described in detail later.

The optical path changing means is disposed to face each of the three incidence planes of the dichroic prism, and is configured to transmit the light incident upon branching from the optical splitting means, and to reflect the light reflected by the image generating means to reflect the critical surfaces 51a and 53a. , First to third critical prism (51, 53, 55) having 55a).

The image generating means 60 may include first to third reflective liquid crystal display elements which generate an image from each of the incident light beams through the first to third critical prisms 51, 53, and 55 and reflect the image. 61, 63, and 65, and the first through third reflection type liquid crystal display elements 61, 63, 65 and the color prism 70, respectively, the first through to transmit the light in one polarization direction And a third polarizer (62, 64, 66). 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 first to third polarizers 62, 64, and 66 transmit light having a predetermined polarization converted by the polarization converter 40, and the first to third reflective liquid crystal display devices 61, 63, 65) The light converted to light of different polarization in each is blocked to provide an image corresponding to each wavelength region toward the projection lens unit 80.

The color prism 70 has three entrance faces and one exit face. The three incident plane angles face each of the first, second and third critical angle prisms 51, 53, and 55, and the path of the incident light such that light incident through each critical angle prism is directed toward the one exit surface is described above. Convert To this end, the color prism 70 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 80 is disposed between the color prism 70 and a screen (not shown) to enlarge and project the light incident from the color prism 70 toward the screen.

Hereinafter, with reference to the drawings, look at the operation of the reflective project apparatus according to an embodiment of the present invention.

Light emitted from the lamp 11 and reflected from the reflector 13 is incident on the glass rod 31 in the visible light region while the infrared light and the ultraviolet light are blocked by the band filter 20. The light of the incident visible light becomes uniform light while passing through the glass rod 31 while maintaining the unpolarized state. The uniform light is incident on the polarization converter 40 in a substantially parallel state while minimizing light loss while passing through the first half relay lens system I. While passing through the polarization converter 40, the light without polarization becomes light of the P polarization component without loss of light.

The incident light of the P-polarized light component is transmitted or reflected according to the wavelength in the first dichroic mirror DM1 and branched in different paths. That is, the light transmitted through the first dichroic mirror DM1 is split into the light of the red and green wavelengths by the second dichroic mirror DM2 as the light of the red and green wavelengths. That is, light in the green wavelength region that passes through the second dichroic mirror DM2 passes through the critical surface 51a of the first critical prism 51 and the first polarizer 62 to allow the first reflective liquid crystal display device ( 61). In addition, the light of the red wavelength range reflected by the second dichroic mirror DM2 passes through the critical surface 53a of the second critical prism 53 and the second polarizer 64 to form the second reflective liquid crystal display device ( 64). The light reflected from the first dichroic mirror DM1 is light in a blue wavelength region, and passes through the reflecting mirrors M2 and M3 to the critical surface 55a of the third critical prism 55 and the third polarizer 66. The light penetrates and enters the third reflective liquid crystal display device 65.

The rear half relay lens system is disposed between the first dichroic mirror DM1 and each of the first to third critical angle prisms 51, 53, and 55. Is provided so that uniform light is irradiated to each of the first to third reflective liquid crystal display elements 61, 63, and 65.

Each of the first, second, and third reflective liquid crystal display elements 61, 63, and 65 is independently driven for each pixel to correspond to image signals of green, red, and blue to selectively change the polarization direction. Only light that maintains the P polarization component among the light reflected by the first to third reflection type liquid crystal display elements 61, 63, and 65 passes through the first to third polarizers 62, 64, and 66, and the color prism Incident on each of the three incident surfaces of 70.

The color prism 70 synthesizes an image of each color incident through three paths and emits them to one emission surface, and the emitted light is projected onto a screen (not shown) while being enlarged through the projection lens unit 80. do.

As described above, the reflective projection apparatus according to the embodiment of the present invention can greatly increase the light efficiency by converting the light emitted from the light source into the light of one polarization without light loss using a polarization converter for image formation. .

In addition, the front and rear relay lens system By properly disposing the light source, the light loss can be reduced and uniform light can be irradiated onto the reflective liquid crystal display device surface, thereby improving image quality.

Claims (9)

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; A first half relay lens system disposed between the light source and the polarization transducer to make incident light approximately parallel light; 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; A rear half relay lens system arranged in a path between the optical branch means and the optical path changing means; 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; Include, The polarization converter, A cylindrical lens array having an arrangement for focusing and diverging incident parallel light so that a parallel beam having a reduced cross-section is emitted compared to an incident beam; A plurality of polarizing beam splitters for splitting the light irradiated through the cylindrical lens array into first and second light according to polarization components, transmitting the first light and reflecting the second light; Disposed in an area where light secured by the cylindrical lens array does not pass, A plurality of reflecting members for converting an optical path of the second light such that the second light is emitted in a direction parallel to the first light; A λ / 2 phase delay plate for delaying a phase of the first light or the second light so that polarization components of the first light and the second light are the same; The first half relay lens system is sequentially arranged from the light source side, Focal length with positive power A first lens group having; Focal length with positive polarizer and with polarization transducer And a second lens group having the focal length; And The first and second lens groups are arranged to match each other, The second half relay lens system is sequentially arranged from the first half relay lens system. Focal length with positive power A third lens group having; Focal length with positive power A fourth lens group having; Focal length with positive power Including a fifth lens group having the focal length; And And the third and fifth lens groups are arranged such that are matched with each other. The method of claim 1, And a rectangular parallelepiped glass rod disposed on an optical path between the light source and the first half relay lens unit to diffusely reflect the light emitted from the light source to become uniform light. The method of claim 1, And a band pass filter disposed on an optical path between the light source and the first half relay lens system, the band filter configured to block light in the infrared and ultraviolet regions of the light emitted from the light source. delete delete delete The optical branch means according to any one of claims 1 to 5, A first dichroic mirror disposed on a path of the light passing through the polarizer and splitting incident light according to a wavelength region; And a second dichroic mirror which re-branches the light diverged from the first dichroic mirror according to the wavelength region. The reflection may include splitting white light having a predetermined polarization into light of red, blue, and green. Type projection device. The optical path converting means according to any one of claims 1 to 5, First to third critical prisms having a critical surface disposed to face each of the three incidence planes of the dichroic prism, the light being branched from the light-branching means to transmit the light, and the light reflected from the image generating means to reflect the light; Reflective projection apparatus comprising a. The method of claim 8, wherein the image generating means, First to third reflection type liquid crystal display elements for generating an image from each light incident through the first to third critical prism and reflecting it; And first to third analyzers disposed between each of the first to third reflective liquid crystal display elements and the dichroic prism, and configured to transmit light in one polarization direction.