CN1200559C - Projection display device that can be used to display electronic images - Google Patents

Abstract

A projection display device for displaying electronic images is provided, which comprises a light source for generating red, green and blue polarized lights with different polarities; three modulation units, each modulating monochromatic polarized light in a reflection mode and changing the polarity of the modulated monochromatic polarized light to display an electronic image; the light splitting prism group comprises a first light splitting mirror and a third light splitting mirror which are arranged along a diagonal line, a first polarization splitting mirror and a second polarization splitting mirror which are arranged along the other diagonal line, and a first polarity conversion mirror arranged between the second polarization splitting mirror and the third polarization splitting mirror. The first color splitter, the first and the second polarization splitter and the first polarity conversion mirror are used for dividing the red, green and blue polarized light of the light source into red, green and blue three monochromatic light, respectively leading the red, green and blue polarized light into three modulation units to change the polarity of the three monochromatic light, generating three modulated light in a reflection mode, inputting the three modulated light into the third polarization splitter, and synthesizing the three modulated light into an output light beam to display an electronic image.

Description

Projection display device that can be used to display electronic images

technical field

The invention provides a projection display device, in particular, a projection display device which can be used to display electronic images.

Background technique

Refer to Figure 1. FIG. 1 is a schematic structural diagram of a projection display device 10 of a known liquid crystal projector. The projection display device 10 includes an approximately white light source 12 for generating light; a uniform illumination device 14, which is arranged in front of the light source 12, and is used to convert the light emitted by the light source 12 into a uniform and approximately square beam; The color separation device 16 is used to divide the light generated by the light source 12 into input light of three different colors: red (R), green (G), and blue (B); an approximately square three-color prism 18, which includes three The input surface and an output surface are used for synthesizing the input light beams of three different colors of red, green and blue into one output light beam and outputting; the three-light modulation device 20 is made of a monochromatic liquid crystal panel, and is respectively arranged on three of the three color prisms 18. In front of the input face, it is used to modulate three beams of input light to produce output light containing electronic images; three focusing lenses 17, 19, 21 are respectively arranged in front of the three-light modulating device 20, and are used to combine the color separation device 16 The generated red, green and blue three beams of input light are gathered on the three-light modulating device 20; on screen 24. Wherein, the light modulating device 20 is composed of a transparent monochrome liquid crystal display for displaying a monochrome electronic image. The three-color prism 18 synthesizes three monochrome images generated by the three monochrome liquid crystal displays 20 into one color image, and outputs it from its output surface.

The color separation device 16 includes a first dichroic mirror 26, which is used to separate a kind of color light from the square white light beam generated by the uniform irradiation light device 14, for example, the red input light can be separated in a transmission mode, and a reflector 27, used to reflect the red input light produced by the dichroic mirror 26 to the focusing lens 17, a second dichroic mirror 28, used to separate the remaining two kinds of color light, for example, the blue input light is passed by the dichroic mirror 26 The reflected light is separated by reflection and transmitted to the focusing lens 19 , while the green input light is passed through the second dichroic mirror 28 and then transmitted to the focusing lens through two lenses 30 and two reflecting mirrors 32 . It is obvious from the structure of the color separation device 16 that the lengths of the optical paths traveled by the red, blue and green input light rays in the color separation device 16 are different. The red and blue input light passes through a dichroic mirror and a reflector respectively, and the optical paths of the two are roughly equal, but the optical path of the green input light is much longer than that of the red and blue input light. The illuminance of the light will be affected by the distance. Therefore, in order to make up for the illuminance loss caused by the long optical path of the green input light, two lenses 30 are respectively arranged at the front ends of the two reflectors 32 to focus the light to solve the illuminance caused by the long transmission distance of the green input light. Insufficiency and uniformity are different issues. However, the arrangement of the two lenses 30 makes the optical path of the green input light more complicated, and increases the cost of the projection display device 10 . These problems are all caused by the different lengths of the light passing through the color separation device 16 due to the red, blue and green input light rays produced by the color separation device 16 .

Contents of the invention

Therefore, the main purpose of the present invention is to provide a projection display device, which can solve the above-mentioned problem of different optical path lengths by using a dichroic prism, and can simplify the optical design of the known projection display device 10 .

The present invention provides a projection display device that can be used to display electronic images, which includes a light source for generating red, green and blue polarized light with different polarities, which provides a single-color polarized light and a two-color polarized light Three-color polarized light composed of light, and the polarization direction of one polarized color light in the two-color polarized light must be different from the other two polarized color lights; three modulation units, each modulation unit is used to reflect Modulate a monochromatic polarized light in a manner, and change its polarity to display an electronic image; a dichroic prism group, which includes a first dichroic mirror and a third dichroic mirror arranged along a diagonal line, along the Another diagonally arranged first and second polarizers, and a first polarity conversion mirror (retarder film) arranged between the second and third polarizers. Wherein, the first dichroic mirror, the first and second polarizer mirrors, and the first polarity conversion mirror are used to divide the red, green and blue three-color polarized light of the light source into red, green and blue three monochromatic lights, and It respectively introduces three modulation units to change the polarity of the red, green and blue monochromatic light, and generates three modulated lights in a reflective way, which is input to the third polarizer, and synthesizes the three modulated lights into one output beam to display electronic images .

Description of drawings

FIG. 1 is a schematic structural view of a projection display device of a known liquid crystal projector;

2 is a schematic structural view of a projection display device of a liquid crystal projector of the present invention;

Fig. 3 is the structural representation of dichroic prism group;

Fig. 4 is a structural schematic diagram of a modulation unit;

5 is a schematic structural view of the light source device of the projection display device of the present invention;

6 and 7 are structural schematic diagrams of another embodiment of the light source device and the projection display device of the present invention, respectively.

Explanation of symbols in the attached drawings:

40, 110 projection display device 42 light source device

50 beam splitting prism group 52 projection lens

54 screens 60A～E prism

70 first polarity conversion mirror

76 reflective image modulation device

78 quarter-wave delay device 80 light source

82 optical polarization device

44, 46, 48 modulation units

62, 86, 88, 102, 112 dichroic mirrors

64, 66, 68 polarizers

84, 100 spectroscopic device

90, 92, 104, 106 mirrors

94, 108 1/2 wavelength delay device

Detailed ways

Refer to Figures 2 to 4. FIG. 2 is a schematic structural diagram of the projection display device 40 of the liquid crystal projector of the present invention. FIG. 3 is a schematic structural diagram of the beam splitting prism group 50 . FIG. 4 is a schematic structural diagram of a modulation unit. The projection display device 40 includes a light source device 42 , three modulation units 44 , 46 and 48 , a dichroic-polarization beam splitter prism 50 , and a projection lens 52 . The light source device 42 is used to generate red, green, and blue polarized lights with uniform illumination and different polarities. The polarization directions are different. For example, the polarized light produced by the light source device 42 of the present invention is red (R), green (G*), blue (B) three-color polarized light, wherein the polarization direction of the green (G*) color polarized light is the same as The polarization directions of red (G) and blue (B) dichromatic polarized light are different. Modulation units 44, 46 and 48 are used to reflectively modulate a monochromatic polarized light and change its polarization. Dichroic prism group 50 is then used to accept red (R), green (G*), blue (B) three-color polarized light, and it is respectively introduced in three modulation units 44, 46 and 48 for modulation, change After its polarity, the three monochromatic polarized lights are synthesized into a beam of output light output. The projection lens 52 is disposed in front of the output surface of the dichroic prism set 50 for projecting the output light generated by the dichroic prism set 50 onto a screen 54 .

The dichroic prism group 50 is composed of five triangular prisms 60A, 60B, 60C, 60D, and 60E, and the contact surfaces of the five prisms 60A, 60B, 60C, 60D, and 60E are respectively coated with a coating as a mirror surface. Dichroic prism group 50 comprises a first dichroic mirror 62, a first polar mirror 66, a second polar mirror 68, a third polar mirror 64, and a first polarity conversion mirror (retarder film) 70 . The first dichroic mirror 62 and the third dichroic mirror 64 are arranged along the diagonal of the dichroic prism group 50, while the first and second dichroic mirrors 66, 68 are arranged along the other diagonal of the dichroic prism group 50 set up. The first polarity switching mirror 70 is then arranged between the second and third polarizing mirrors 68 , 64 .

Each modulation unit 44, 46 and 48 is all shown in Figure 4, and each unit includes a reflective image modulation device 76 for modulating an incident light in a reflective manner to produce a reflected light, and a quarter wavelength The delay device 78 is used for delaying the incident light and the reflected light by 1/4 wavelength, so that the reflected light generated by the modulating unit is 1/2 wavelength different from the incident light, so that the polarity is reversed. Wherein, the reflective image modulation device 76 may be composed of a digital micro-mirror device or a reflective liquid crystal display.

As shown in FIG. 2 , when the red (R), green (G*), and blue (B) three-color polarized light with uniform illumination and different polarities produced by the light source device 42 enters the dichroic prism group 50, the first The dichroic mirror 62 will separate the blue (B) color polarized light in a reflective manner, and pass to the first polarized mirror 66, while the red (G), green (G*) two-color polarized light is transmitted through the first polarized light. dichroic mirror 62, and pass to the second dichroic mirror 68. Here, the coating design of the first polarizer 66 is such that the incident S-type polarized light is reflected and the P-type polarized light is penetrated, so the first polarizer 66 divides the blue (B) color polarized light to reflect Introduced into the first modulation unit 48 by way of the first modulation unit 48, and after the polarity is changed by the first modulation unit 48, it is reflected as blue (B*) modulated light, passes through the first polarizer 66, and guides to the third polarizer 64 . The coating design of the second polarizer 68 also makes it reflect the incident S-type polarized light and penetrate the P-type polarized light, so the red (R) light belonging to the S-type polarized light is reflected to the second modulation unit 44 , and then modulated, reflected and changed its polarization direction into P-type polarized light, which passes through the second polarizer 68 . The green (G*) light that originally belongs to the P-type polarized light first passes through the second polarizer 68 to the third modulation unit 46, and then modulates, reflects and changes its polarization direction to S-type polarized light. reflected by the second polarizer 68. Then, the red (R*; P-type) and green (G; S-type) modulated light returned from the second and third modulation units 44 and 46 will be directed to the third polarization through the first polarity conversion mirror 70 Mirror 64. The first polarity conversion mirror 70 converts the polarity of the red modulated light (R*; P type) to another polarity (R; S type), but does not change the polarity of the green modulated light (G; S type). The design of the third polarizer 64 also makes the reflected incident S-type polarized light penetrate the P-type polarized light, so the blue (B*) color modulation light from the first polarizer 66 will be penetrated, and The red (R) and green (G*) modulated light from the second polarizer 68 will be reflected and synthesized into an output beam to enter the projection lens 52 . In this way, the projection display device 40 of the present invention simply utilizes the dichroic prism group 50 to inject red (R), green (G*), and blue (B) three-color polarized light into the first dichroic mirror 62, and then passes through the first dichroic mirror 62. Light splitting and pole splitting are arranged and converted, and finally the blue (B*), green (G) and red (R) three-color modulated light is synthesized into an output beam by the third polarizing mirror 64, and projected to the fluorescent light beam through the projection lens 52. Act 54 on.

Since the dichroic prism group 50 utilizes the combination of the dichroic mirror 62 and the polar mirrors 64, 66, and 68 to separate the red, green, and blue light beams of different colors in the white light, and respectively introduce them into corresponding light modulation devices for modulation. , so in terms of the requirements of the incident light, the light source device 42 must provide three-color polarized light composed of a single-color polarized light and a two-color polarized light, and the polarized color of one polarized color light in the two-color polarized light The polarization direction must be different from the other two polarized color lights, so that it can be output together into an output beam into the projection lens 52 after passing through the beam splitting prism group 50 and splitting the poles according to the design.

Referring to FIG. 5 , FIG. 5 is a schematic structural diagram of the light source device 42 of the projection display device 40 of the present invention. The light source device 42 includes a lamp tube 80, which is used to generate white light composed of red, green and blue (RGB) non-polarized light, and a light polarizing device 82, which is arranged in front of the light source 80, and is used to emit light from the lamp tube 80. The white light WW*(RR*GG*BB*) is converted into red, green and blue (RGB) three-color polarized light, and a light splitting device 84 is used to convert the three-color polarized light (RGB) with the same polarity into different Polarized three-color polarized light (RG*B). The spectroscopic device 84 includes two dichroic mirrors 86, 88 for separating or combining red, green, and blue light, two reflectors 90, 92 for reflecting light, and a half-wavelength delay The device 94 is used to change the polarity of the single-color polarized light or the double-color polarized light to generate red, green and blue three-color polarized light with different polarities. When the three-color polarized light (RGB) with the same polarity enters the spectroscopic device 84, the dichroic mirror 86 separates the green light (B) in a transmission manner, and reflects it through the reflector 72, passing through half the wavelength The delay device 94 turns the polarized light of green (G*) color, and then uses the dichroic mirror 88 to reflect and output the spectroscopic device 84, while the red (R) and blue (B) light is sequentially transmitted by the dichroic mirror 86 and the reflector 90 After reflection, it passes through the dichroic mirror 88 and outputs the spectroscopic device 84, so that three-color polarized light (RG*B) with different polarities can be obtained. In this way, the three-color polarized light (RG*B) with different polarities generated by the light source device 42 enters the dichroic prism group 50 through the first dichroic mirror 62 in FIG. 2 .

Referring to FIG. 6 and FIG. 7 , they are schematic structural diagrams of a spectroscopic device 100 and a projection display device 110 according to another embodiment of the present invention. The difference between the spectroscopic device 100 and the spectroscopic device 84 is that the spectroscopic device 100 only includes a dichroic mirror 102, two reflection mirrors 104, 106 and a half-wavelength retardation device 108, which can produce red polarities of different polarities. (R), green (G*), blue (B) three-color polarized light, the output direction of the line (G*) color polarized light and red (R), blue (B) two-color polarized light is formed A vertical angle, and then enter the first dichroic mirror 112 of the dichroic prism group 50 from the two mutually perpendicular input surfaces of the dichroic prism group 50 in FIG. 7 . The coating composition of the first dichroic mirror 112 of the projection display device 110 is different from the coating composition of the first dichroic mirror 62 of the projection display device 40, and the first dichroic mirror 112 will reflect green (G*) light and blue (B*) light. ) light and allow red (R) light to pass through; in addition, other components of the projection display device 110 are the same as those of the projection display device 40 .

In addition, the above-mentioned first polarity conversion mirror 70 converts the polarity of the modulated red light beam to another polarity, but does not affect the polarity of the green light beam. However, it is also possible to use the first polarity conversion mirror 70 that converts the polarity of the green light beam into another polarity without affecting the polarity of the red light beam. At this time, only the first and third polarizers 66, 64 This polarity conversion mirror is arranged between, to change the polarity of blue light beam, can make the polarity of monochromatic light beam (blue) and dichromatic light beam (red and green) different, so, the 3rd pole splitter 64 That is, the modulated monochromatic light beams (blue) and bicolor light beams (red and green) are synthesized into an output light beam by means of reflection and transmission respectively, and projected onto the screen 54 .

From the structures of the projection display devices 40 and 110, it can be clearly seen that the optical path distances passed by the input light rays of red, green and blue in the projection display devices 40 and 110 are approximately equal, and the optical paths are very short, so The projection display devices 40 and 110 do not need to use any redundant lens and reflector components to help separate the input light rays or compensate for the illuminance variation caused by the difference in the length of the optical path. Compared with the projection display device 10 of the known liquid crystal projector shown in FIG. 1 , the projection display device of the present invention has a very simple structure, low cost and better effect.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention fall within the scope of the present invention.

Claims (12)

1. A projection display device comprising: A light source for generating red, green and blue polarized light with different polarities, which provides three-color polarized light composed of a single-color polarized light and a two-color polarized light, and the two-color polarized light The polarization direction of one polarized colored light must be different from the other two polarized colored lights; First, second and third modulation units, each modulation unit is used to modulate a monochromatic polarized light in a reflective manner and change its polarity; A dichroic prism group, which includes a first dichroic mirror, a first dichroic mirror, a second dichroic mirror, and a third dichroic mirror, the first dichroic mirror and the third dichroic mirror are along the arranged diagonally, and the first and second polarizers are arranged along another diagonal; a first polarity conversion mirror, located between the second and third polarizers; Wherein, the first dichroic mirror is used to divide the three-color polarized light of the light source into a first monochromatic light and a dichromatic light, and transmit them to the first and second polarizers respectively, the first A polarizer guides the first monochromatic light to the first modulation unit, and guides the first modulated light reflected by the first modulation unit to the third polarizer, and the second polarizer guides the two-color light according to its polarity Divide into two monochromatic light, and lead to the second and third modulation unit respectively, and then guide the second and third modulated light reflected by the second and third modulation unit to the third polarization through the first polarity conversion mirror mirror, the first polarity conversion mirror converts the polarity of one modulated light beam in the second and third modulated light beams into another polarity, and the third polarized mirror synthesizes the first, second and third modulated light beams into an output beam. 2. The projection display device according to claim 1, further comprising a projection lens for projecting the output light beam of the third polarizer onto a screen. 3. The projection display device as claimed in claim 1, wherein said dichroic prism group is composed of an approximately square dichroic prism, said first dichroic mirror and the third polar mirror are arranged along the diagonal of the dichroic prism group, and The first and second pole splitters are arranged along the other diagonal line of the beam splitting prism group. 4. The projection display device as claimed in claim 1, wherein the three-color polarized light of the light source is composed of a monochromatic polarized light and a two-color polarized light, so the monochromatic and two-color polarized light is formed by the first dichroic mirror The opposite sides of the beam enter the first dichroic mirror. 5. The projection display device of claim 1, wherein the three-color polarized light of the light source is a single light beam, which enters the first dichroic mirror from one side of the first dichroic mirror. 6. The projection display device according to claim 1, wherein the first polarizer transmits the first monochromatic light to the first modulation unit in a reflective manner, and the first modulated light reflected by the first modulation unit is transmitted through The first polarizer passes to the third polarizer. 7. The projection display device according to claim 1, wherein the first polarizer transmits the first monochromatic light to the first modulation unit in a transmission manner, and the first modulated light transmitted by the first modulation unit is transmitted through The first polarizer passes to the third polarizer. 8. The projection display device according to claim 1, wherein the second polarizer directs the second monochromatic light in the two-color light to the second modulation unit in a reflective manner, and directs the third monochromatic light in the two-color light The second modulated light reflected by the second modulated unit is transmitted to the third polarized mirror through the second polarized mirror, and the third modulated light reflected by the third modulated unit is transmitted by The second polarizer mirror is directed toward the third polarizer mirror in a reflective manner. 9. The projection display device of claim 1, wherein each modulating unit comprises a reflective image modulating device for modulating an incident light in a reflective manner to generate a reflected light, and a quarter-wave delay device for Each of the incident light and the reflected light is delayed by a quarter wavelength, so that the polarity of the reflected light generated by the modulation unit is opposite to that of the incident light. 10. The projection display device of claim 9, wherein the reflective image modulating device is a digital micro-mirror device. 11. The projection display device of claim 9, wherein said reflective image modulation device is a reflective liquid crystal display. 12. The projection display device as claimed in claim 1, wherein said light source comprises a lamp tube for generating nonpolar red, green and blue three-color light, and a light polarizing device for converting the nonpolar three-color light into three colors Polarized light, a beam splitter group for separating three-color polarized light into a monochromatic polarized light and a two-color polarized light, and a wavelength delay device for converting the monochromatic polarized light or two-color polarized light The polarity of light, thus producing red, green and blue polarized light with different polarities.

Images