JP2003207741A - Projection type display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a technique for improving the display contrast of a projection type display. <P>SOLUTION: A projection optical system of the projection type display separates the luminous flux projected by an illumination optical system 100 having an extra-high pressure mercury lamp into components of red luminous flux, green luminous flux, and blue luminous flux which are modulated by liquid crystal panels 431, 421, and 411 and put together by a cross dichroic prism 400 to form a color image, which is projected by a projection part 500 on a screen SC. A blue attenuation filter provided on an explosion-proof glass 113 at a lighting opening part of a lighting device 110 attenuates the blue component at the circumferential part of the luminous flux and the rate of a high- contrast component of light in use is increased to use a liquid crystal panel 411, so that the display contrast can be improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device.

[0002]

2. Description of the Related Art In recent years, a technique of a projection display device which displays by modulating and projecting light has been spreading. By using a projection display device, an image such as a presentation is displayed based on an image signal received from an information terminal such as a personal computer, or an image such as a television or a movie is received based on an image signal received from an AV device or the like. Can be projected.

In a projection display device, light from a light source is split into three colors of red (R), green (G), and blue (B), and the transmittance is modulated for each pixel by a liquid crystal panel prepared for each color. To do. A color image is projected by combining the images of the respective colors thus modulated.

[0004]

However, in general, even when the liquid crystal panel is driven so as to block light, some light leaks. The amount of leakage differs depending on the structure of the liquid crystal panel and the wavelength of light, but in B, the amount of leakage often becomes relatively large. Therefore, for B, the contrast characteristic, that is, the ratio of the lightness in the brightest case to the brightness in the darkest case is lower than that of the other colors. In the past, due to such contrast characteristics, sufficient image quality could not be obtained. Also, due to leakage of blue, black was displayed as bluish gray. Such a problem was more remarkable as the light amount of the light source increased.

In order to improve the leakage of blue light, a method of inserting a filter after the spectroscopic analysis to reduce only the amount of blue light can be considered. However, in this method, when white light is displayed,
This causes another problem that the color balance is lost.

The present invention has been made to solve the above problems, and it is an object of the present invention to improve the blue contrast characteristic in a projection display device without extremely impairing the color balance.

[0007]

Means for Solving the Problems and Their Actions / Effects In order to solve at least a part of the above problems, the present invention adopts the following configuration.

The projection type display device of the present invention includes a light source unit for emitting a light beam, a decomposing unit for decomposing the light beam emitted by the light source unit into a blue light beam and a light beam of another color, and each of the decomposed light beams. A modulating unit for performing liquid crystal modulation, a combining unit for combining the modulated light beams to generate a color image, a projection unit for projecting and displaying the combined light beams, and a blue color around the light beams. And a blue attenuating portion for attenuating at least a part of the component.

By doing so, it is possible to improve the blue contrast performance without extremely impairing the color balance based on the principle described below.

FIG. 1 is an explanatory view showing the function of a liquid crystal panel to block light. As shown in FIG. 1A, a point o on the liquid crystal panel and an xy plane are set, and a ray incident on the xy plane from a direction indicated by an angle θ is shown in FIG.
The interruption performance is shown in (b). FIG. 1B qualitatively shows the light blocking rate.

When the angle θ is close to 90 degrees, the liquid crystal panel can block most light rays. Therefore, high contrast performance can be exhibited. But,
As the angle θ departs from 90 degrees and the incident direction becomes shallower,
The ability to block light rays is reduced and the contrast performance is reduced.

According to the present invention, since the blue color is attenuated in the vicinity of the luminous flux, it is possible to efficiently improve the contrast characteristic of the liquid crystal panel while transmitting the light at the central portion of the luminous flux, which accounts for a considerable proportion of the total luminous energy. As a result, it is possible to improve the contrast performance of blue, improve the problem of bluish gray when displaying black, and maintain the color balance when the liquid crystal panel has a high transmittance.

The modulator can be constructed by using a light valve (light modulator) that modulates an incident light beam such as a liquid crystal panel. When the modulator is a liquid crystal panel, it may be of a transmissive type, or of a reflective type or a reflective / transmissive type.

Various modes of attenuating the blue component around the luminous flux performed by the blue attenuator can be considered. For example, a filter having a blue attenuation coat on a lens or the like may be provided, an independent blue attenuation filter may be provided, or a dichroic mirror that reflects a blue component in the peripheral portion of the light flux may be used. Also, it is possible to perform uniform attenuation for a certain area around the light flux,
The attenuation amount may be changed for each place. When changing the amount of attenuation for each location, it is conceivable to increase the degree of attenuation toward the periphery. Further, the blue attenuator may have an adjustable amount of attenuation, and may be controlled by a display controller or the like that controls the processing of the liquid crystal panel.

In the projection display device of the present invention, the blue attenuating portion may be provided between the light source portion and the disassembling portion.

In the projection display device of the present invention, the blue attenuating portion may be provided on the explosion-proof glass that constitutes a part of the light source portion.

In the projection display device of the present invention, the first lens array for splitting the light flux into a plurality of split light fluxes and the second lens array for superposing the plurality of split light fluxes so as to emit a substantially uniform light flux. Lens array, and the blue attenuator may be provided in the first or second lens array.

In the projection display device of the present invention, a polarization optical section for converting the light flux into linearly polarized light having a uniform polarization direction may be provided, and the blue attenuating section may be provided in the polarization optical section.

In the projection display device of the present invention, the blue attenuating portion may attenuate the blue light flux emitted by the decomposing portion after being decomposed.

By doing so, the blue attenuator can be constructed without considering the attenuation for components other than blue. Therefore, the blue attenuator can be realized with a material and a structure that are relatively simple. For example, the attenuation may be performed so as to completely block the light rays of all colors of the light flux.

In the projection display device according to the present invention, a relay lens for diverting the blue light of the decomposed light flux to enter the combining portion is provided, and the blue attenuating portion is provided in the relay lens. Good.

In the projection type display device of the present invention, the blue attenuating portion may be provided in a multilayer lens.

In the projection display device of the present invention, the blue attenuating portion may be provided in a diaphragm provided in the projection portion.

In the projection display device of the present invention, the blue attenuating portion may be formed by providing a light shielding portion around at least a part of the lens provided in the optical path through which the blue light flux passes.

In the projection display device of the present invention, the blue attenuating portion is formed by making the diameter of at least a part of the lenses provided in the optical path through which the blue light flux passes smaller than the diameter of the blue light flux. It may be done.

In the projection type display device of the present invention, the blue attenuating section may perform asymmetrical optical axis center attenuation according to the viewing angle contrast characteristic of the modulating section with respect to the blue light flux.

By doing so, efficient damping can be performed based on the principle described below.

The characteristic of the breaking performance shown in FIG. 1 is θ <90
And the range of 90 <θ are not symmetrical. Such asymmetry is based on a physical property of the liquid crystal panel, which is called a rubbing direction. Such asymmetry is shown in FIG.
When the measurement is performed by rotating the x-axis on the liquid crystal panel surface in (a), it is found that light leakage is large on the predetermined semicircle side and small on the opposite semicircle side based on the rubbing direction.

Therefore, depending on the characteristics of the breaking performance,
By attenuating the blue attenuator in a shape that is asymmetric with respect to the optical axis center, it is possible to efficiently attenuate blue light that cannot be blocked by the liquid crystal panel while transmitting a considerable proportion of the total light amount.

In the projection type display device of the present invention, the blue attenuating portion may perform attenuating in a symmetrical manner about the optical axis.

By doing so, the light beam at the central portion of the light beam can be effectively used, so that a decrease in the amount of blue light can be avoided. Therefore, it is possible to avoid a light amount imbalance with other colors, and it is possible to perform display without color unevenness.

There are various possible modes of attenuating the blue component around the light flux performed by the blue attenuator. For example, it is possible to consider attenuation around a predetermined circle or rectangle around the optical axis or other outer portion of a point symmetric figure.

When the projection optical system includes a lens array, the optical axes of the cell lenses included in the lens array may be considered.

The present invention can be configured in various modes such as a projection type display device and a projection type display method using a projection optical system.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in the following order based on Examples. A. First Example: A-1. Projection optical system: A-2. Blue Attenuation Filter: B. Second Embodiment: C.I. Other examples:

A. First Example: A-1. Projection Optical System: FIG. 2 is an explanatory diagram showing an example of a schematic configuration of the projection optical system of the projection display apparatus. In the projection optical system, the luminous flux emitted by the illumination optical system 100 is decomposed into the respective components of the red luminous flux (R), the green luminous flux (G), and the blue luminous flux (B) by the color light separating optical system 200, and each luminous flux is divided into three. After being modulated by the liquid crystal panels 411, 421, 431, the light beams are combined by the cross dichroic prism 400 to generate a color image, which is projected on the screen SC by the projection optical system 500. At this time, the above processing is performed while guiding the optical path by the reflection mirrors 160, 230, 320 and 340.

The projection display device has a receiver and a liquid crystal panel drive section. The receiver inputs an analog image signal or a digital image signal supplied from an information terminal such as a personal computer or a video signal supplied from an AV device or the like. The liquid crystal panel drive section generates a drive signal for driving the liquid crystal panels 411, 421, 431 based on the input data. Based on these functions, projection type display can be performed using the projection optical system shown in FIG.

The illumination optical system 100 comprises the ultra high pressure mercury lamp 1
11 and a parabolic mirror 112, a first lens array 120, and a second lens array 130.
A polarization conversion element 140 and a superimposing lens 150. The illumination opening portion of the lighting device 110 is configured as an explosion-proof glass 113. First lens array 120 and second
The lens array 130 and the superimposing lens 150 have the function of making the light flux uniform in each part. As a result, it is possible to uniformly illuminate the entire liquid crystal panel and perform projection without uneven brightness. The light beam emitted by the illumination device 110 is divided into a plurality of divided light beams by the plurality of small lenses 131 included in the first lens array 120,
The second lens array 130 and the multi-layer lens 140 are stacked. Further, the polarization conversion element 140 has a function of making the polarization of the light flux uniform according to the physical characteristics of the liquid crystal panels 411, 421, 431. The lighting device 110
Corresponds to the light source unit of the present invention.

The color light separation optical system 200 has dichroic mirrors 210 and 220. The dichroic mirror 210 transmits red (R) color light and reflects green (G) and blue (G) color light. The dichroic mirror 220 transmits blue (B) color light and reflects green (G) color light. As a result, the illumination optical system 10
The light flux emitted by 0 can be decomposed into components of a red light flux (R), a green light flux (G), and a blue light flux (B). Here, the red light flux (R) and the green light flux (G) are introduced into the liquid crystal panels 432 and 431, respectively. The blue light flux (B) is bypassed by the relay optical system 300 and introduced into the liquid crystal panel 411. The color light separating optical system 200 corresponds to the disassembling section of the present invention.

The relay optical system 300 includes an entrance lens 310.
And a relay lens 330. Relay optical system 3
00 has a function of causing the blue light flux (B) emitted from the color light separation optical system 200 to detour and enter the liquid crystal panel 411 and the cross dichroic prism 400.

The liquid crystal panels 431, 421, 411 modulate the light flux according to the drive signal generated by the liquid crystal panel drive section. The liquid crystal panels 431, 421, 411 are transmissive liquid crystal panels, and are used as light valves (light modulators) that modulate incident light flux. Color light separation optical system 200
The red (R), green (G), and blue (B) luminous fluxes emitted by the field lenses 432, 422, and 41, respectively.
The light enters the liquid crystal panels 431, 421, 411 via The liquid crystal panels 431, 421, 411 correspond to the modulator of the present invention.

The cross dichroic prism 400 is
The light beams of the three colors modulated by the liquid crystal panels 431, 421, 411 are combined to generate a color image. The cross dichroic prism 400 corresponds to the combining unit of the present invention.

The projection optical system 500 displays the color image generated by the cross dichroic prism 400 on the screen S.
Project on C. As a result, a color image is displayed on the screen SC. The projection optical system 500 corresponds to the projection unit of the present invention.

A-2. Blue Attenuation Filter: FIG. 3 is an explanatory diagram showing a blue attenuation filter provided in the illumination device 110. Here, FIG. 3A shows a shape viewed from the optical axis direction, and FIG. 3B shows a perspective view thereof. The blue attenuation filter 60a corresponds to the blue attenuation unit of the present invention.

Here, the blue attenuating filter 60a is constructed by coating a dielectric multilayer film on the explosion-proof glass 113 provided at the illumination opening of the illuminating device 110, as shown by the shaded area in FIG. ing. Blue attenuation filter 60
To a, the color light of blue (B) is reflected and the other color lights of red (R) and green (G) are transmitted.

The blue attenuating filter 60a shown in FIG. 3 has a function of attenuating the blue component in the peripheral portion of the luminous flux emitted from the illuminating device 110. Due to such attenuation, in the light flux irradiated to the liquid crystal panel 411, as a result, it is possible to reduce the amount of light that is deviated from the optical axis parallel direction and in which the contrast performance is particularly deteriorated. The blue attenuating filter 60a has a function of maximizing such a function depending on the rubbing direction of the liquid crystal panel 411.
It is set to 0.

According to the projection display apparatus of the present embodiment, the light around the central portion of the luminous flux, which accounts for a considerable proportion of the total luminous energy, is transmitted by the attenuation around the luminous flux, while the blue light that cannot be blocked by the liquid crystal panel is efficiently transmitted. And improve the blue contrast performance. It is possible to improve the problem of bluish gray when displaying black and to maintain the color balance in the state where the transmittance of the liquid crystal panel is high. B. Second embodiment:

FIG. 4 is an explanatory diagram showing a blue attenuation filter provided in the illuminating device 110 and having a shape symmetrical with respect to the optical axis. Further, FIG. 5 is an explanatory diagram showing a modified example of the blue attenuation filter provided in the illumination device 110 and having a shape symmetrical with respect to the optical axis. Figure 4
FIG. 5A and FIG. 5A show the shape of the blue attenuation filter viewed from the optical axis direction. Further, a perspective view of each of them is shown in FIG. 4 (b) and FIG. 5 (b).

The blue attenuation filters 60b and 60c are the first
Similar to the case of the embodiment, the filter is provided on the explosion-proof glass 113 provided at the illumination opening portion of the illumination device 110, but it is the first in that it is configured as a filter having a shape symmetrical to the optical axis.
This is different from the case of the embodiment. The blue attenuating filter 60b has a circular shape, and the blue attenuating filter 60c has a rectangular shape, and attenuates light in a shape symmetrical with respect to the optical axis.

According to the projection display apparatus of the present embodiment, the light rays at the central portion of the light beam can be effectively used, so that the reduction in the amount of blue light can be avoided. It is possible to avoid an imbalance in the amount of light with other colors, and it is possible to perform display without color unevenness.

C. Other examples:

In the following, various other configurations of the blue attenuator of the present invention will be described. First, the case where the blue attenuation portion is provided in the lens array will be described.

FIG. 6 is an explanatory diagram showing a blue attenuation filter provided in the lens array. The lens array 700 having the blue attenuation filter 61 includes the first lens array 120.
Or as the second lens array 130. The blue attenuation filter 61 shown in FIG. 6 is a filter that attenuates in a shape asymmetric with respect to the optical axis.

FIG. 7 is an explanatory view showing a modification of the filter provided in the lens array. Lens array 700a, 7
00b and 700c are blue attenuation filters 61, respectively.
a, 61b, 61c. Similar to the lens array 700, these lens arrays may be used as the first lens array 120 or the second lens array 1
It may be used as 30. These blue attenuation filters 61a, 61b, 61c are filters that perform attenuation symmetrically with respect to the optical axis. Here, when viewed for each small lens, the blue attenuation filters 61b and 61c and the blue attenuation filter 61 shown in FIG. 6 are symmetrical about the optical axis in all the small lenses, but not in the blue attenuation filter 61a. .

Regarding the position where the blue attenuating portion is provided, various positions other than the lens array can be considered. The shape of attenuation in the following description may be symmetric with respect to the optical axis or may be asymmetric with respect to the optical axis. As the specific example of the shape, the one shown in the previous embodiment can be used.

As a place where a filter is provided by coating a lens or the like through which a light beam passes for attenuating blue color, the polarization conversion element 140 or the multi-layer lens 150,
The reflection mirrors 160, 320 and 340 may be mentioned.

Further, liquid crystal panels 411, 421, 431
It is also conceivable to coat a lens included in the projection optical system 500 as a blue attenuating portion provided in a later optical path. A blue attenuation filter may be provided at the position of the diaphragm 510 included in the projection optical system 500.

Further, it may be considered to provide a blue attenuating portion in the relay optical system 300. Relay optical system 300
Has a function of diverting and guiding the blue light flux to the cross dichroic prism 400. In the relay optical system 300, it is possible to form a blue attenuating portion by coating the relay lens 330 or blackening it to provide a light shielding portion. In this case, the black-painted portion may be a paint that completely blocks the light flux of all colors. It is also conceivable to configure the blue attenuator by making the diameter of the lens smaller than the diameter of the blue light flux that passes through. In the case where the relay optical system 300 is provided with the blue attenuator, it is not necessary to consider the transmissivity of light other than blue, and therefore, there is an advantage that the material and configuration of the blue attenuator are relatively easy.

Although the projection type display device according to the present invention has been described based on the embodiments, the embodiments of the present invention described above are for facilitating the understanding of the present invention and limit the present invention. Not something to do. The present invention can be modified and improved without departing from the spirit and scope of the claims.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a light blocking function of a liquid crystal panel.

FIG. 2 is an explanatory diagram showing an example of a schematic configuration of a projection optical system of a projection display device.

FIG. 3 is an explanatory diagram showing a blue attenuation filter provided in the lighting device.

FIG. 4 is an explanatory diagram showing an optical axis symmetrical filter provided in the lighting device.

FIG. 5 is an explanatory diagram showing a modified example of a filter having an optical axis symmetric shape provided in the lighting device.

FIG. 6 is an explanatory diagram showing a blue attenuation filter provided in a lens array.

FIG. 7 is an explanatory diagram showing a modified example of a filter having a symmetrical shape with respect to the optical axis provided in the lens array.

[Explanation of symbols]

100 ... Illumination optical system 110 ... Lighting device 111 ... Ultra high pressure mercury lamp 112 ... Parabolic mirror 113 ... Illumination opening 120 ... First lens array 130 ... second lens array 131 ... Small lens 140 ... Polarization conversion element 150 ... Superimposing lens 200 ... Color light separation optical system 210, 220 ... Dichroic mirror 300 ... Relay optical system 310 ... Incident lens 330 ... Relay lens 400 ... Cross dichroic prism 432, 422, 412 ... Field lens 411, 421, 431 ... Liquid crystal panel 500 ... Projector 510 ... Aperture 520 ... Projection lens system 411 ... Liquid crystal panel 160, 230, 320, 340 ... Reflective mirror 60a, 60b, 60c ... Blue attenuation filter 700, 700a, 700b, 700c ... Lens array 61, 61a, 61b, 61c ... Blue attenuation filter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 21/14 G03B 21/14 A 33/12 33/12 H04N 9/31 H04N 9/31 C F term ( Reference) 2H088 EA12 HA13 HA24 HA28 MA02 MA05 2H091 FA05X FA26X FA41Z LA15 LA17 MA07 5C060 GA02 HC12 HC16 HC20 HC22 HC24 HD02 JA00

Claims (13)

[Claims] 1. A projection type display device, comprising: a light source unit for emitting a light beam; a decomposing unit for decomposing the light beam emitted by the light source unit into a blue light beam and a light beam of another color; and the decomposed light beam. A modulation unit for performing liquid crystal modulation for each of the light beams, a combining unit for combining the modulated light beams to generate a color image, a projection unit for projecting the combined light beams for display, and A projection display device comprising: a blue attenuator that attenuates at least a part of a blue component. 2. The projection display device according to claim 1, wherein the blue attenuating unit is provided between the light source unit and the disassembling unit. 3. The projection display device according to claim 1, wherein the blue attenuating portion is provided on explosion-proof glass forming a part of a light source portion. 4. The projection display device according to claim 1, wherein the first lens array for splitting the light flux into a plurality of split light fluxes, and the plurality of splittings to emit a substantially uniform light flux. A second lens array for superposing light fluxes, wherein the blue attenuator is provided in the first or second lens array. 5. The projection display device according to claim 1, further comprising a polarization optical unit that converts the light flux into linearly polarized light having a uniform polarization direction, and the blue attenuation unit is provided in the polarization optical unit. Projection display device. 6. The projection display device according to claim 1, wherein the blue attenuating unit attenuates the blue light flux emitted by the decomposition unit. 7. The projection display device according to claim 1, further comprising a relay lens for diverting the blue light of the decomposed light flux to enter the combining unit, wherein the blue attenuating unit includes: Projection display device provided on the relay lens. 8. The projection display device according to claim 1, wherein the blue attenuating portion is provided in a multilayer lens. 9. The projection display device according to claim 1, wherein the blue attenuating portion is provided in a diaphragm provided in the projection portion. 10. The projection display device according to claim 1, wherein the blue attenuating portion is formed by providing a light shielding portion around at least a part of a lens provided in an optical path through which the blue light flux passes. Projection display device. 11. The projection display device according to claim 1, wherein the blue attenuating portion has a diameter of at least a part of a lens provided in an optical path through which the blue light flux passes, from a diameter of the blue light flux. A projection display device formed by reducing the size. 12. The projection display device according to claim 1, wherein the blue attenuating section performs asymmetrical optical axis center attenuating according to the viewing angle contrast characteristic of the modulating section with respect to the blue light flux. apparatus. 13. The projection display device according to claim 1, wherein the blue attenuating portion attenuates about an optical axis.