JP3957472B2 - Projection display device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a projection display apparatus such as a liquid crystal projector.
[0002]
[Prior art]
FIG. 3 is a schematic diagram showing an optical system of a conventional single-plate liquid crystal projector. White light (including the three primary colors R, G, and B) emitted from the light source 50 is incident on the time division color filter 56. The time division color filter 56 includes an incident side polarizing plate 51, a red cell 52, a green cell 53, a blue cell 54, and an output side polarizing plate (transmission axes intersecting the incident side) 55. The incident white light is sequentially separated into red light, green light and blue light in a time division manner and transmitted. Specifically, polarized light of one color is rotated by 90 ° by energization control to the red cell 52, the green cell 53, and the blue cell 54, and this can pass through the emission side polarizing plate 55, so that only one color is emitted. By performing the one-color emission process by sequentially switching, red, green, and blue are sequentially output in a time division manner. In the black-and-white liquid crystal display panel 57, when red light is emitted, the pixel is driven with a red video signal, and when green light is emitted, the pixel is driven with a green video signal. When blue light is emitted, the pixels are driven by the blue video signal. As a result, color image light is output from the liquid crystal display panel 57.
[0003]
[Problems to be solved by the invention]
However, in the above conventional projection display apparatus, when one selected color is output, the other two colors are removed, and the light use efficiency is poor and it is difficult to increase the brightness. Had.
[0004]
SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a projection display apparatus that can achieve high brightness using a single-plate time-division color scheme.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problem, a projection display apparatus according to the present invention is a projection display apparatus that projects an image by modulating light emitted from a light source with a light valve. Time-division color separation switching means that separates light into red light, green light, and blue light, and sequentially switches emission positions of red light, green light, and blue light at a predetermined timing, and light emitted from the light source Light guide means for guiding each light to the three divided areas of the light valve through the three light emitting portions of the time division color separating means, and for each color in each of the three divided areas of the light valve. And a control means for supplying a switching signal to the time-division color separation switching means in accordance with the switching timing.
[0006]
If it is said structure, the white light radiate | emitted from the light source will be isolate | separated into red light, green light, and blue light, and all will be guide | induced to each area | region divided into three at the same timing, and will be used. Therefore, the light use efficiency is high, and the brightness of the screen can be increased.
[0007]
The light guide means adjusts the light from the light source in advance to a light beam corresponding to the 1/3 region of the light valve and guides it to the time division color separation switching means. The light may be guided to each of the three divided regions of the light valve. In such a configuration, the light guide means may comprise an integrator lens.
[0008]
Alternatively, the light guide means adjusts each light from the three light emitting portions of the time division color separation switching means to a light flux corresponding to 1/3 area of the light valve and guides it to each of the three divided areas of the light valve. It may be like this. In such a configuration, the light guide means may comprise an anamorphic lens.
[0009]
A time-division color separation switching means, a first optical means for sequentially selecting one of red light, green light, and blue light having a first polarization direction and converting the polarization direction into a second polarization direction; Of the light that has passed through the first optical means, the second optical means that changes the optical path of only the light having the second polarization direction, and the red light and the green light having the first polarization direction that have passed through the second optical means. Or a third optical unit that sequentially selects one color of blue light and converts the polarization direction into the second polarization direction, and light having the second polarization direction among the light that has passed through the third optical unit. And a fourth optical means for changing only the optical path.
[0010]
In the above configuration, the second optical means and / or the fourth optical means may be formed of a polarizing beam splitter. The light valve may be formed of a liquid crystal display panel, and light guided to the liquid crystal display panel may be unified into light having a first polarization direction or light having a second polarization direction. Further, the light valve may be composed of a liquid crystal display panel, and the light guided to each of the three divided regions of the liquid crystal display panel may be unified with light in the first polarization direction or light in the second polarization direction. . The light valve may be formed of a transmissive or reflective panel that does not include a polarizing plate.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
A liquid crystal projector according to an embodiment of the present invention will be described below with reference to FIGS.
[0012]
FIG. 1 is a diagram showing an optical system of a single plate type liquid crystal projector of this embodiment. The light emitting unit 2 of the light source 1 is composed of an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like, and the irradiation light is emitted as parallel light by the parabolic reflector 3 and guided to the integrator lens 4.
[0013]
The integrator lens 4 is composed of a pair of lens groups 4a and 4b. In general, each pair of lenses guides light emitted from the light source 1 to the entire surface of a liquid crystal display panel 17 to be described later. However, in this embodiment, the liquid crystal display panel 17 is guided to the central 1/3 region of the region divided into 3 in the vertical direction (3 regions in a horizontal stripe shape). The light that has passed through the integrator lens 4 is guided to the polarization conversion device 5.
[0014]
The polarization conversion device 5 is configured by a polarization beam splitter array (hereinafter referred to as a PBS array). The PBS array includes a polarization separation film and a phase difference plate (1 / 2λ plate). Each polarization separation film of the PBS array passes, for example, p-polarized light out of the light from the integrator lens 3 and changes the optical path of s-polarized light by 90 °. The s-polarized light that has been subjected to optical path polarization is reflected by an adjacent polarization separation film, converted into p-polarized light by the retardation plate provided on the front side (light emission side), and emitted. On the other hand, the p-polarized light transmitted through the polarization separation film is emitted as it is. That is, almost all light is converted to p-polarized light. The light passing through the polarization conversion device 5 is guided to the time division color filter device 7 through the condenser lens 6.
[0015]
The time-division color filter device 7 includes a first one-color polarization rotation unit 8, a first polarization beam splitter 9, a second one-color polarization rotation unit 10, a second polarization beam splitter 11, and a phase difference plate 12. And comprising.
[0016]
The first one-color polarization rotation unit 8 includes an incident side polarizing plate 8a, a red cell 8b, a green cell 8c, and a blue cell 8d. As described above, in the configuration including the polarization conversion device 5, the incident side polarizing plate 8a is not necessarily required. The incident side polarizing plate 8a transmits p-polarized light. One of the red cell 8b, the green cell 8c, and the blue cell 8d is selected, and the polarized light of any one of the red light, the green light, and the blue light is rotated by 90 ° and converted into s-polarized light. For the red cell 8b, green cell 8c, and blue cell 8d themselves, SID (SOCIETY FOR INFORMATION DISPLAY SYMPOSIOM DIGEST OF TECHNICAL PAPERS) VOLUME XXXI P.96-P.99 (9.4: High Throughput Color Switch For Sequential Color Projection) And are known.
[0017]
The first polarization beam splitter 9 transmits the p-polarized light, changes the optical path of the s-polarized light by 90 °, and guides it to the relay lens 13.
[0018]
The second one-color polarization rotating unit 10 includes an incident-side polarizing plate 10a, a red cell 10b, a green cell 10c, and a blue cell 10d. The incident side polarizing plate 10a is not always necessary. The incident side polarizing plate 10a transmits p-polarized light. One of the red cell 10b, the green cell 10c, and the blue cell 10d is selected, and one color of polarized light is rotated by 90 ° to be converted into s-polarized light.
[0019]
The second polarization beam splitter 11 transmits the p-polarized light, changes the optical path of the s-polarized light by 90 °, and guides it to the relay lens 14.
[0020]
The phase difference plate 12 converts p-polarized light that has passed through the second polarizing beam splitter 11 into s-polarized light and guides it to the total reflection mirror 15. The total reflection mirror 15 guides the s-polarized light that has passed through the second polarization beam splitter 11 to the relay lens 16.
[0021]
The optical system composed of the relay lens 13 and the reflection mirror 21 condenses the s-polarized light emitted from the first polarization beam splitter 9 in the upper 1/3 region of the liquid crystal display panel 17. The relay lens 14 condenses the s-polarized light emitted from the second polarization beam splitter 11 in the central region 1/3 region of the liquid crystal display panel 17. The optical system including the relay lens 16 and the reflection mirror 21 condenses the s-polarized light emitted from the total reflection mirror 15 in the lower 1/3 region of the liquid crystal display panel 17. Note that the optical system including the relay lens and the reflection mirror is not limited to the arrangement and the number of optical elements shown in the drawing. Further, not only the reflection mirror but also an optical element such as a prism may be used.
[0022]
The liquid crystal display panel 17 includes an incident-side polarizing plate, a panel portion in which liquid crystal is sealed between a pair of glass substrates (pixel electrodes and alignment films are formed), and an output-side polarizing plate. In this embodiment, the incident-side polarizing plate is transmissive for s-polarized light.
[0023]
The video signal supply unit 18
i. A red pixel image is supplied to the upper third pixel group of the liquid crystal display panel 17 (in this case, the red cell 8b of the first one-color polarization rotation unit 8 is selected, and the red s-polarized light is liquid crystal by the relay lens 13 or the like. Led to the upper 1/3 pixel group of the display panel 17), and supplies the green pixel image to the 1/3 pixel group of the middle side of the liquid crystal display panel 17 (the green cell 10c of the second one-color polarization rotation unit 10 is provided). The green s-polarized light is guided to the central 1/3 pixel group of the liquid crystal display panel 17 by the relay lens 14 and the like, and the blue pixel image is supplied to the lower 1/3 pixel group of the liquid crystal display panel 17 ( A first state in which the blue s-polarized light is guided to the lower 1/3 pixel group of the liquid crystal display panel 17 by the relay lens 16 or the like;
ii. A green pixel image is supplied to the upper third pixel group of the liquid crystal display panel 17 (at this time, the green cell 8c of the first one-color polarization rotation unit 8 is selected, and the green s-polarized light is liquid crystal by the relay lens 13 or the like. Led to the upper 1/3 pixel group of the display panel 17, and supplies the blue pixel image to the 1/3 pixel group of the middle side of the liquid crystal display panel 17 (the blue cell 10 d of the second one-color polarization rotation unit 10 is provided). The blue s-polarized light is led to the central 1/3 pixel group of the liquid crystal display panel 17 by the relay lens 14 and the like, and the red pixel image is supplied to the lower 1/3 pixel group of the liquid crystal display panel 17 ( A second state in which the red s-polarized light is guided to the lower 1/3 pixel group of the liquid crystal display panel 17 by the relay lens 16 or the like;
iii. A blue pixel image is supplied to the upper third pixel group of the liquid crystal display panel 17 (at this time, the blue cell 8d of the first one-color polarization rotation unit 8 is selected, and the blue s-polarized light is liquid crystal by the relay lens 13 or the like. Led to the upper 1/3 pixel group of the display panel 17, and the red pixel image is supplied to the 1/3 pixel group of the middle side of the liquid crystal display panel 17 (the red cell 10 b of the second one-color polarization rotation unit 10 is provided). The red s-polarized light is guided to the central 1/3 pixel group of the liquid crystal display panel 17 by the relay lens 14 and the like, and the green pixel image is supplied to the lower 1/3 pixel group of the liquid crystal display panel 17 ( A third state in which green s-polarized light is guided to the lower 1/3 pixel group of the liquid crystal display panel 17 by the relay lens 16 or the like;
Are repeatedly formed. FIG. 2 is an explanatory diagram showing the state of switching of colored light in the optical path (1), the optical path (2), and the optical path (3) in FIG. 1 at each timing (t1, t2, t3). .
[0024]
The control unit 19 performs video signal switching supply control to the liquid crystal display panel 17 described above, and performs cell selection control of the first one-color polarization rotation unit 8 and the second one-color polarization rotation unit 10.
[0025]
The projection lens 20 projects light (color image light) modulated by the liquid crystal display panel 17 onto a screen (not shown).
[0026]
If it is said structure, the white light radiate | emitted from the light source 1 will be isolate | separated into red light, green light, and blue light, and all will be guide | induced to each area | region divided into three at the same timing. Since it is used, the light utilization efficiency is high, and the brightness of the screen can be increased.
[0027]
In this embodiment, the light from the light source 1 is preliminarily adjusted by the integrator lens 4 to a light beam corresponding to the 1/3 region of the liquid crystal display panel 17 and led to the time division color filter device 7, and this time division color filter device The light from the three light emission locations 7 is guided to each of the three divided areas of the liquid crystal display panel 17. However, the present invention is not limited to this, and each light from the three light emission locations of the time division color filter device 7 is used. May be adjusted to a luminous flux corresponding to 1/3 region of the liquid crystal display panel 17 and guided to each of the three divided regions of the liquid crystal display panel 17. In this configuration, an anamorphic lens may be provided. In addition, the liquid crystal display panel 17 is used as a light valve, but the present invention is not limited to this. For example, an optical element or the like that can arrange a large number of micromirrors corresponding to pixels and individually change the angle may be used. It is.
[0028]
【The invention's effect】
As described above, according to the present invention, in a projection display apparatus that generates a color image by time-division color separation with a single plate, it is possible to increase the light use efficiency and increase the screen brightness. Play.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a liquid crystal projector according to an embodiment of the invention.
FIG. 2 is an explanatory diagram showing how color light is guided at each timing.
FIG. 3 is a vertical side view of a conventional liquid crystal projector.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light source 4 Integrator lens 5 Polarization conversion apparatus 8 1st color polarization rotation part 9 1st polarization beam splitter 10 2nd color polarization rotation part 11 2nd polarization beam splitter 17 Liquid crystal display panel

Claims (7)

In a projection display apparatus for projecting an image by modulating white light emitted from a light source with a light valve, the light emitted from the light source is separated into red light, green light, and blue light, and at a predetermined timing. The time division color separation switching means for sequentially switching the emission locations of red light, green light and blue light, and the light from the three light emission locations of the time division color separation means are divided into three parts of the light valve. In addition, the light guide means for leading to each area and the pixel drive signal for each color are sequentially switched and supplied to each of the three divided areas of the light valve, and the time division color separation switching means is switched according to the switching timing. Control means for supplying a signal ,
The time-division color separation switching means is a first optical means for sequentially selecting one of red light, green light and blue light having a first polarization direction and converting the polarization direction into a second polarization direction; Of the light that has passed through the first optical means, the second optical means that changes the optical path of only the light having the second polarization direction, the red light having the first polarization direction that has passed through the second optical means, and green A third optical means for sequentially selecting one color of light or blue light and converting the polarization direction to the second polarization direction; and a second polarization direction of the light that has passed through the third optical means. A projection-type image display device comprising: a fourth optical means for changing an optical path of only light .   2. The projection type image display apparatus according to claim 1, wherein the light guide means adjusts the light from the light source in advance to a light beam corresponding to a 1/3 region of the light valve and guides it to the time division color separation switching means. A projection display apparatus characterized in that each light from three light emitting portions of the color separation switching means is guided to each of the three divided regions of the light valve.   3. The projection display apparatus according to claim 2, wherein the light guide means includes an integrator lens.   2. The projection type image display device according to claim 1, wherein the light guide means adjusts each light from the three light emitting portions of the time-division color separation switching means to a light beam corresponding to a third region of the light valve. A projection-type image display device, characterized by being guided to each of the three divided regions of the light valve.   5. The projection display apparatus according to claim 4, wherein the light guide means includes an anamorphic lens. 6. The projection display apparatus according to claim 1, wherein the second optical means and / or the fourth optical means comprises a polarization beam splitter. 7. The projection display apparatus according to claim 1, wherein the light valve is a transmissive or reflective panel that does not include a polarizing plate.

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