JP3904589B2 - Video display device - Google Patents

Description

  The present invention relates to a projection device for projecting an image on a screen using a light valve element such as a liquid crystal panel or a reflective video display device, such as a liquid crystal projector device, a reflective video display projector device, a liquid crystal television or a projection type. The present invention relates to a video display device such as a display device, a color separation unit thereof, and an optical unit, and particularly provides a technique suitable for improving white balance.

2. Description of the Related Art Projection-type video display devices such as liquid crystal projectors that enlarge and project an image on a liquid crystal panel by applying light from a light source such as a light bulb to a light valve element such as a liquid crystal panel are known.
This type of video display device adjusts light from a light source by changing it to light and shade for each pixel with a light valve element, and projects it onto a screen or the like. A twisted nematic (TN) type liquid crystal display element, which is a typical example of a liquid crystal display element, has a polarization direction before and after a liquid crystal cell formed by injecting liquid crystal between a pair of transparent substrates having a transparent electrode film. Two polarizing plates are arranged so as to be different from each other by 90 °. By combining the action of rotating the polarization plane by the electro-optic effect of the liquid crystal and the action of selecting the polarization component of the polarizing plate, the amount of transmitted light of the incident light is combined. Is controlled to display image information. In recent years, in such a transmissive or reflective liquid crystal display element, the element itself has been miniaturized, and the performance such as resolution has been rapidly improved.
For this reason, a display device using this liquid crystal display element has also been improved in size and performance, and not only performs video display by a video signal or the like as in the prior art, but also a projection type liquid crystal display device as an image output device of a personal computer. Has also been proposed. This type of projection display apparatus is required to have good brightness and color reproducibility, particularly good white balance.
Currently, there are metal halide lamps, ultra-high pressure mercury lamps, xenon lamps and the like as light sources used as light sources for video display devices, all of which have a high ratio of green light of 500 to 600 nm, and y in the CIE color system. The value was white.
Therefore, conventionally, for example, a liquid crystal display device that eliminates yellow bright lines as described in Patent Document 1 has been used. However, in the CIE color specification, the y stimulus value of yellow bright lines (stimulates the cells of the eye). Stimulus value) is about 0.500, and in order to lower the y value of white, much light must be excluded, resulting in insufficient brightness, and the x value in the CIE color specification is There was a problem that it was greatly lowered.

JP-A-3-67216

An object of the present invention is to provide an image display device with improved white balance, a color separation unit thereof, and an optical unit.
Another object of the present invention is a projection type image display device in which white balance adjustment is very difficult, and an image display device in which white balance is improved by minimizing loss of brightness, its color separation unit, and optical A unit is provided.

In order to achieve the object of the present invention, an image display device according to the present invention includes an illumination system including a light source, a color separation system for separating light according to color, a light valve element, and light emitted from the light valve element. And a magnifying means for magnifying and projecting, and controlling the spectral characteristics of the color separation system to exclude light in the wavelength band selected within the range of about 450 nm to about 550 nm from the light path.
In this image display device, the color separation system includes a color filter having a red light filter, a green light filter, and a blue light filter, and the B light filter is selected from a range of about 450 nm to about 530 nm. A filter that emits light having a wavelength less than a set value; and the G light filter is a second set value that is selected from a range of about 500 nm to about 550 nm and a range of about 570 nm to about 600 nm. And a filter that emits light having a wavelength of 3 or less. In this video display device, the first set value is set to about 500 nm, the second set value is set to about 520 nm, and the third set value is set to about 580 nm.
In this image display device, the color separation system separates green light and blue light so that the blue light band has a wavelength equal to or less than a first set value selected from a range of about 490 nm to about 550 nm. And a means for shielding blue light having a second set value or more selected from the range of about 450 nm to about 530 nm. In this video display device, the first set value is set to about 520 nm, and the second set value is set to about 500 nm.
In this video display device, the color separation system separates green light and blue light so that the green light band has a wavelength equal to or longer than a first set value selected from a range of about 450 nm to about 530 nm. The color separation means to be set and green light in a band not less than the second set value selected from the range of about 500 nm to about 550 nm and not more than the third set value selected from the range of about 570 nm to about 600 nm are emitted. Means. In this video display device, the first set value is set to about 500 nm, the second set value is set to about 520 nm, and the third set value is set to about 580 nm.
In this video display device, the color separation system separates green light and blue light so that the green light band has a wavelength equal to or longer than a first set value selected from a range of about 450 nm to about 530 nm. Separation color separation means to be set, and means for emitting green light having a second set value or more selected from a range of about 500 nm to about 550 nm. In this video display device, the first set value is set to about 500 nm, and the second set value is set to about 520 nm. In this video display device, the light source is a discharge lamp. The discharge lamp is an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like.

In the video display device, the light is divided into red light, green light, and blue light by the color separation system, and each lens and mirror on the blue light path from the illumination system to the light valve element. For light having a wavelength of about 400 nm to about 430 nm. In the image display device, the light is divided into red light, green light, and blue light by the color separation system, and each lens on the blue light path from the color separation system to the light valve element; The mirror is set to pass about 95% or more of light having a wavelength of about 680 to about 700 nm.
The color separation unit according to the present invention separates light from an illumination system having a lamp into light of a plurality of colors and enters the light valve element. The color separation unit includes a red light filter, a green light filter, and a blue light filter. A color filter, wherein the B light filter is a filter that emits light having a wavelength equal to or less than a first set value selected from a range of about 450 nm to about 530 nm, and the green light filter is about 500 nm to about The filter is configured to emit light having a wavelength not less than the second set value selected from the range of 550 nm and not more than the third set value selected from the range of about 570 nm to about 600 nm.
The color separation unit according to the present invention separates light from an illumination system having a lamp into light of a plurality of colors and enters the light valve element. The color separation unit separates green light and blue light, and the blue light A separation color separation means for setting the band of the wavelength of the first wavelength to be equal to or less than a first set value selected from a range of about 490 nm to about 550 nm, and a second set value selected from a range of about 450 nm to about 530 nm Means for shielding the above blue light.
The color separation unit according to the present invention separates light from an illumination system having a lamp into light of a plurality of colors and enters the light valve element. The color separation unit separates green light and blue light, Separation color separation means for setting the band of the wavelength to be equal to or longer than the first set value selected from the range of about 450 nm to about 530 nm, and the second set value selected from the range of about 500 nm to about 550 nm As described above, there is provided means for emitting green light in a band equal to or lower than the third set value selected from the range of about 570 nm to about 600 nm.
The color separation unit according to the present invention separates light from an illumination system having a lamp into light of a plurality of colors and enters the light valve element. The color separation unit separates green light and blue light, Separation color separation means for setting the band to have a wavelength equal to or longer than a first set value selected from a range of about 450 nm to about 530 nm, and a second set value or more selected from a range of about 500 nm to about 550 nm Means for emitting green light.

  In these color separation units, the light is divided into red light, green light, and blue light by the color separation system, and each lens and mirror on the blue light path from the illumination system to the light valve element is provided. It is set so that light having a wavelength of about 400 nm to about 430 nm passes about 95% or more. Further, in these color separation units, the light is divided into red light, green light and blue light by the color separation system, and each lens on the blue light path from the illumination system to the light valve element and The mirror is set to pass about 95% or more of light having a wavelength of about 680 to about 700 nm.

  An optical unit according to the present invention includes an illumination system having a lamp and a color separation system that separates light from the illumination system, and is used in an apparatus that enlarges and projects light from the color separation system through a light valve means. The optical unit includes a color filter having a red light filter, a green light filter, and a blue light filter, and the B light filter has a wavelength equal to or less than a first set value selected from a range of about 450 nm to about 530 nm. A filter that emits light, and the green light filter is not less than a second set value selected from a range of about 500 nm to about 550 nm and not more than a third set value selected from a range of about 570 nm to about 600 nm. The filter is configured to emit light having a wavelength.

  An optical unit according to the present invention includes an illumination system having a lamp and a color separation system for separating light from the illumination system, and enlarges and projects the light from the color separation system via a light valve means. The optical unit used for the separation color separates green light and blue light, and sets the blue light band so that the wavelength is equal to or less than a first set value selected from a range of about 490 nm to about 550 nm. The separating means and blue light having a second set value or more selected from the range of about 450 nm to about 530 nm are shielded.

An optical unit according to the present invention includes an illumination system having a lamp and a color separation system that separates light from the illumination system, and is used in an apparatus that enlarges and projects light from the color separation system through a light valve means. An optical unit that separates the green light and the blue light, and sets a band of the green light so that the wavelength of the green light is not less than a first set value selected from a range of about 450 nm to about 530 nm; Means for emitting green light in a band not less than a second set value selected from a range of about 500 nm to about 550 nm and not more than a third set value selected from a range of about 570 nm to about 600 nm.
An optical unit according to the present invention includes an illumination system having a lamp and a color separation system that separates light from the illumination system, and is used in an apparatus that enlarges and projects light from the color separation system through a light valve means. An optical unit that separates the green light and the blue light, and sets a band of the green light so that the wavelength of the green light is not less than a first set value selected from a range of about 450 nm to about 530 nm; And means for emitting green light having a second set value or more selected from the range of about 500 nm to about 550 nm.

In order to achieve an object of the present invention, an image display device according to the present invention includes an illumination system having a light source, a color separation system that separates light emitted from the light source into a plurality of colors, and light from the color separation system. In a video display device comprising a means for irradiating a light valve element on which an optical image corresponding to a video signal is formed and a projection means for projecting light emitted from the light valve element, on the optical path of the illumination means The light emitted from the light source is separated into red light, green light, and blue light and is incident on the light valve means, and is equal to or less than the wavelength of the first set value selected from the range of about 490 to about 550 nm. Color separation means for obtaining blue light, and light having a wavelength equal to or greater than a second set value selected from a range of about 450 to about 530 nm for the blue light separated by the color separation means is shielded against the light valve element. Means and Provided. In this video display device, the light shielding means is selected from a dichroic mirror, a light absorbing material, and a light shielding plate.
An image display device according to the present invention includes an illumination system having a light source, a color separation system that separates light emitted from the light source into a plurality of colors, and an optical image corresponding to the image signal of light from the color separation system. In a video display device comprising a means for irradiating a light valve element and a projection means for projecting light emitted from the light valve element, the light emitted from the light source is arranged on the optical path of the illuminating means. Color separation means that separates light, green light, and blue light and enters the light valve means to obtain green light having a wavelength of a first set value selected from a range of about 450 to about 530 nm, and the color separation Means for blocking light having a wavelength equal to or shorter than a wavelength of a set value selected from a range of about 490 to about 550 nm among the green light separated by the means from the light valve. In this video display device, the light shielding means is selected from a dichroic mirror, a light absorbing material, and a light shielding plate.
An image display device according to the present invention includes an illumination system having a light source, a color separation system that separates light emitted from the light source into a plurality of colors, and an optical image corresponding to the image signal of light from the color separation system. In a video display device comprising means for irradiating the light valve element and projection means for projecting the light emitted from the light valve element, the light emitted from the light source is red light, green light, blue light or red light. A color filter for limiting the wavelength range of green light, blue light, and white light to enter the light valve element, a color filter for red light, a color filter for green light, and a blue filter for blue light, and the green light The color filter for light attenuates light having a wavelength less than a set value selected from a range of about 500 to about 550 nm. In this video display device, the green color filter is a dichroic mirror.
The image display device according to the present invention separates the emitted light of the light source that emits light into red light, green light, and blue light, and irradiates the light valve element on which an optical image corresponding to the image signal is formed, thereby displaying the image In the video display device for projecting the light emitted from the element, a part of the means for causing the blue light to be incident on the light valve element has a characteristic of transmitting about 95% or more of light having a wavelength of about 400 to about 430 nm.
Further, the image display device according to the present invention separates the emitted light of the light source that emits light into red light, green light, and blue light, and irradiates the light valve element on which an optical image corresponding to the image signal is formed, In the video display device for projecting the light emitted from the video display element, a part of the means for causing the red light to enter the light valve means has a characteristic of allowing light having a wavelength of about 680 to about 700 nm to pass through 95% or more. . In this video display device, a part of the incident means is composed of a lens and a mirror.
In order to achieve the object of the present invention, in the present invention, at least a light source, an illuminating means having an action of irradiating emitted light from the light source onto an irradiated surface, an image display element for modulating light, In a video display device having projection means for projecting light emitted from the video display device onto a screen or a display surface equivalent thereto, the video display device is arranged with at least a predetermined angle with respect to the optical axis. The light emitted from the light source by the first color separation means is separated by a predetermined wavelength in the range of about 490 to about 550 nm, and is on the optical path of the light on the short wavelength side thus separated. A second color separation means is provided. The second color separation means is arranged so that light having a predetermined wavelength in the range of about 450 to about 530 nm is discharged from the optical path to the image display element.
The image display device has at least two color separation means arranged at a predetermined angle with respect to the optical axis, and emits about 450 light emitted from the light source by the first color separation means. To about 530 nm, and a second color separation means is disposed on the separated optical path of the light on the long wavelength side. The second color separation means is arranged so that light having a predetermined wavelength in the range of about 500 to about 550 nm is discharged from the optical path to the image display element.
Alternatively, the image display means has at least one color filter that transmits or reflects only green light and passes the image display element, and the color filter has a predetermined wavelength of about 450 to about 550 nm. The light having a wavelength is configured to have a transmission rate of 50% or less at each wavelength. In addition, a configuration in which a wavelength of about 400 to about 430 nm is allowed to pass by 70% or more with respect to the passing configuration. In addition, a configuration in which a wavelength of about 680 to about 700 nm is allowed to pass by 70% or more with respect to the configuration that passes through.

As described above, according to the present invention, since light having a high y value in the vicinity of 500 to 530 nm can be excluded, the y value of the projected image can be lowered and the x value can be raised.
Further, it is possible to freely adjust the chromaticity of white by adjusting the pass wavelength range of a color filter such as a dichroic mirror.
Further, by utilizing light having a wavelength in the vicinity of 400 to 420 nm, the white y value can be lowered without lowering the screen illuminance.
Further, since no other special mechanism is used, a decrease in transmittance can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings using examples.

FIG. 1A is a schematic diagram showing a first embodiment of the video display device according to the present invention, and FIG. 1B is a schematic diagram showing a second embodiment of the video display device according to the present invention. FIG. 1A shows a projection type video display device using a transmission type light valve element, and FIG. 1B shows a projection type video display device using a reflection type light valve element.
In FIG. 1A and FIG. 1B, the projection type video display apparatus is provided with a light source 1. The light source 1 is a white lamp such as an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, a mercury xenon lamp, or a halogen lamp. Light emitted from the light source 1 is collected by an elliptical, parabolic, or aspherical reflector 2 and enters the illumination system 3. The illumination system 3 is composed of at least one lens or at least one polarization conversion element, and efficiently emits light emitted from the light source 1 and reflected by the reflector 2 to the light valve elements 4A and 4B, for example, liquid crystal display elements. have. In FIG. 1A, light from the illumination system 3 is incident on the light valve element 4 through a color filter 5 (described later with reference to FIG. 2). The light incident on the light valve element 4 </ b> A passes through the light valve element 4 </ b> A, is enlarged by the projection lens 6, and an image is displayed on the screen 7.
In FIG. 1B, the light incident on the light valve element 4 </ b> B through the color filter 5 is reflected by the light valve element 4 </ b> B, and the reflected light is magnified by the projection lens 6 and then an image is displayed on the screen 7.

  The light valve element 4 (4A, 4B) is provided with a number of liquid crystal display units corresponding to the number of pixels to be displayed (for example, horizontal 800 pixels and vertical 600 pixels each in three colors). The light emitted from the color filter 5 changes the polarization angle of the pixel of the light valve element 4 in accordance with a signal driven from the outside. As a result, an image according to a signal input from the outside is projected.

FIG. 2 is a plan view of the color filter. As shown in the figure, the color filter 5 has an R light filter 5R that transmits only R light (red light), a G light filter 5G that transmits only G light (green light), and only transmits B light (blue light). A B light filter 5B is provided and rotates about the rotation shaft 8. Accordingly, R light, G light, and B light sequentially reach the light valve elements 4A and 4B. As this color filter 5, various filters can be considered. For example, a white filter for increasing the brightness may be added in addition to the light of these three colors, and the color filter may be a combination of not only R, G, and B light but also cyan, magenta, and the like. Therefore, the color filter 5 only needs to be able to separate colored light.
However, as the light source 1, a white lamp such as an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, a mercury xenon lamp, or a halogen lamp is used, but these lamps have a high ratio of green light of 500 nm to 600 nm, and CIE table. The color system is white with a high y value.
In order to solve this point, the transmission characteristics of the B light filter 5B and the G light filter 5G of the color filter 5 used in the video display device shown in FIGS. 1 (a) and 1 (b) are as follows. Set. That is, the B optical filter 5B is configured by a short wave path filter, and a wavelength at which the transmittance is 50% is set to a predetermined value of 480 to 520 nm, for example, 500 nm, and only light having a wavelength shorter than this is transmitted. .
Further, the transmission characteristic of the G optical filter 5G is configured by a band pass filter, the wavelength of transmittance 50% is set to 500 to 550 nm, for example, 520 nm, and the other wavelength of transmittance 50% is a predetermined value of 570 nm to 600 nm, For example, it is set to 580 nm. If it does in this way, light with a wavelength of 520 nm or more and 580 nm or less of light having a wavelength of 500 nm or more incident on the G optical path is transmitted and incident on the light valve elements 4A and 4B, but light with a wavelength of 520 nm or less is transmitted. Reflected and excluded from the optical path.

In this way, light in an arbitrary wavelength region in the vicinity of 480 nm to 550 nm can be excluded from the optical path, and the y value of NW chromaticity can be lowered.
FIG. 3 is a schematic view showing a third embodiment of the video display apparatus according to the present invention. In FIG. 3, a projection type liquid crystal display element is used as a light valve element, and this is R light of the three primary colors of light (red light: light in a wavelength band of approximately 590 to 700 nm), G light (green light: approximately abbreviated). Three-plate projection type liquid crystal display using a total of three sheets corresponding to three colors of B light (blue light, approximately 400 to 500 nm wavelength band) and B light (with a wavelength band of 500 to 590 nm). The device is shown.
In this embodiment, the lamp unit 11 includes a lamp 9, a parabolic reflector reflector 10, and a plurality of condenser lenses (not shown). The lamp unit 11 is a light source such as a lamp 9 such as an ultra-high pressure mercury lamp. The emitted light is reflected by the parabolic reflecting mirror reflector 10, and then the first light composed of a plurality of condensing lenses provided in a rectangular frame having a size substantially equal to the exit opening of the parabolic reflecting mirror reflector 10. The light enters the array lens 12. That is, the light emitted from the lamp unit 11 including the lamp 9 and the reflector 10 is collected and incident on the first array lens 12 for forming a plurality of secondary light source images. Furthermore, the light emitted from the first array lens 12 is composed of a plurality of condensing lenses, arranged in the vicinity where the plurality of secondary light source images are formed, and is a light valve element for R, G, B. The liquid crystal display elements 13R, 13G, and 13B pass through the second array lens 14 that forms individual lens images of the first array lens 12. The emitted light is arranged so as to conform to the lateral pitch of the lens optical axis of each of the second array lenses 14, and is a row of polarizing beam splitters 15 having rhombus prisms of approximately ½ size of each lens width. Incident to A polarizing beam splitter film is attached to the prism surface of the beam splitter 15. Incident light is separated into P-polarized light and S-polarized light by the polarization beam splitter 15. The P-polarized light passes through the polarization beam splitter 15 as it is, and the polarization direction is rotated by 90 ° by the λ / 2 phase difference plate 16 provided on the exit surface of the prism, and is converted into S-polarized light and emitted. The On the other hand, the S-polarized light is reflected by the polarization beam splitter 15, reflected once again in the original optical axis direction in the adjacent rhombus prism, and then emitted as S-polarized light. Thereafter, the light is condensed on the liquid crystal display elements 13R, 13G, and 13B by the condenser lens 17 including at least one lens.
A total reflection mirror 18 is disposed on the optical path between the condenser lens 17 and the liquid crystal display elements 13R, 13G, and 13B, with the normal to the optical axis at an arbitrary angle, for example, 45 degrees. As a result, the optical path can be bent by 90 °, the degree of freedom in the layout of the entire device can be increased, and a smaller device can be made.
The B light (blue) and G light (green) reflecting dichroic mirror 19 which is on this optical path and whose normal is at an angle of 45 ° with respect to the optical axis is within 560 to 610 nm. Light having a predetermined wavelength or more, for example, light having a wavelength of 585 nm or more, that is, R light is transmitted, and light having a predetermined wavelength or less, that is, B light or G light is reflected. The transmitted R light has its optical path bent by a red light reflecting mirror 20 arranged so that its normal is at a predetermined angle with respect to the optical axis, for example, 45 °, and the red light condenser lens 21R and the red light are reflected. The red light exit side polarizing plate 23R provided on the light exit side of the liquid crystal display element 13R after passing through the light entrance side polarizing plate 22R and incident on the liquid crystal display element 13R composed of a counter electrode, liquid crystal, etc. pass. Here, an R transmissive dichroic mirror 24R may be arranged on the incident side of the red light pre-incident polarizing plate 22R or on the output side of the red light condenser lens 21.
The R light emitted from the red light output polarizing plate 23R is reflected by the dichroic prism 25 having a function of reflecting the R light, enters the projection means 26, for example, a zoom lens, and is projected on the screen.

On the other hand, the B light and G light reflected by the B and G reflecting dichroic mirrors 19 enter the G reflecting dichroic mirror 27, and the mirror 27 causes light having a predetermined wavelength of 490 to 550 nm or more, for example, light having a wavelength of 520 nm or more, That is, G light is reflected. After passing through the green condenser lens 21G, this light has a wavelength not less than a predetermined wavelength by a G transmissive dichroic mirror 24G that transmits only light having a wavelength of 550 to 600 nm or less, for example, light having a wavelength of 580 nm or less. Then, the light passes through the green incident-side polarizing plate 22G and enters the green liquid crystal display element 13G. The outgoing light of the green liquid crystal display element 13G passes through the green outgoing side polarizing plate 23G provided on the outgoing side. The G light emitted from the green output polarizing plate 23G is transmitted through the dichroic prism 25 having a function of transmitting the G light, enters the projection means 26, and is projected onto the screen.
Further, the B light, which is the light having the predetermined wavelength or less transmitted through the G reflecting dichroic mirror 27, passes through at least one of the first lenses 28A and 28B constituting the lens group 28, and is reflected for blue light. It is bent by at least one of the mirrors 29A and 29B constituting the mirror group 29 and passes through the blue condenser lens 21B. Thereafter, light having a wavelength not shorter than a predetermined wavelength within 450 to 530 nm, for example, light having a wavelength not longer than 500 nm is transmitted by the dichroic mirror 24B, and then passed through the blue incident polarizing plate 22B. Then, the light enters the blue liquid crystal display element 13B. The light emitted from the blue liquid crystal display element 13B passes through a blue light emission polarizing plate 23B provided on the light emission side of the blue liquid crystal display element 13B. The B light emitted from the blue output polarizing plate 23B is reflected by the dichroic prism 25 having the function of reflecting the B light, and then projected onto the screen by the projection unit 26.
Furthermore, among the optical components from the illumination system to the light valve element, for each lens and mirror after the illumination system, when white light and blue light are passed, an AR coating is used so that light with a wavelength of 400 to 430 nm passes at least 95%. Design thin film coats. In addition, each lens and mirror after the illumination system is designed with a thin film coat such as an AR coat so that 95% or more of light having a wavelength of 680 to 700 nm passes when white light and red light pass.
As described above, the lights corresponding to R, G, and B are separated by the color separation means including the dichroic mirror 19, the reflection mirror 20, the dichroic mirror 27, the lens group 28, and the mirror group 29. The images are synthesized by the color synthesizing means provided, enlarged by the projection lens 26 on the screen by enlarging the images on the liquid crystal display elements 13R, 13G, and 13B corresponding to R, G, and B and projecting them on the screen. A real image is obtained.
In this embodiment, light in an arbitrary wavelength region of about 450 to 550 nm is discharged from the optical path due to the difference in the passing wavelength range of the G reflection dichroic mirror 27 and the dichroic mirror 24B, and the wavelengths of 400 to 430 nm and 680 to 700 nm are eliminated. Since arbitrary light is used effectively, the x value of the chromaticity of NW (normal white) is raised, and the effect of lowering the y value can be obtained. Further, since the pass wavelength range of the G reflecting dichroic mirror 20 and the dichroic mirror 24B can be freely adjusted, the chromaticity can be freely adjusted.
FIG. 4 is a spectral characteristic diagram of a light source used in an image display device according to the present invention, where the horizontal axis indicates the wavelength of light λ (unit: nm) and the vertical axis indicates the relative intensity S. In the figure, a characteristic curve 31 indicated by a solid line indicates the spectral characteristic of an ultra-high pressure mercury lamp that is a typical example of a white light source, and a characteristic curve 32 indicated by a dotted line indicates the spectral characteristic of a metal halide lamp.
As is apparent from the figure, the ultra-high pressure mercury lamp has a higher proportion of light having a high y value especially as the chromaticity of white light than conventional metal halide lamps and xenon lamps. The ratio of B light and R light is small with respect to the 550 nm emission line peak. Therefore, the y value of the chromaticity of white (normally white: NW) on the screen increases. For this reason, a device for lowering the y value is required.
In the present invention, as will be described later, the G light, B light reflecting dichroic mirror 19, G light reflecting dichroic mirror 27, dichroic mirror 24G, and dichroic mirror 24B shown in FIG. Changing the characteristics.
FIG. 5 is a characteristic diagram showing an example of the spectral characteristics of the entire optical component of the video display device shown in FIG. 3, where the horizontal axis indicates the wavelength of light λ (unit: nm) and the vertical axis indicates the relative intensity S. A characteristic curve 33 indicated by a solid line is a spectral characteristic according to the present invention, and a characteristic curve 34 indicated by a dotted line is a conventional spectral characteristic.
In FIG. 5, the characteristic curve 33 indicates the entire optical component with respect to the light source shown in FIG. 3, that is, the incident light from the lamp 9, that is, the GB reflecting dichroic mirror 19, G reflecting dichroic mirror 27, dichroic mirror 24G, dichroic mirror 24B in FIG. The spectral characteristics of the emitted light when passing through other lens groups or light valve elements 13R, 13G, and 13B, the projection lens 26, the cross prism 25, and the like are shown. As is apparent from the characteristic curve 33, in the embodiment of the present invention, light in the wavelength range of 450 nm to 550 nm, and depending on the lamp used, the wavelength band of 480 nm to 540 nm is discharged from the optical path. That is, 95% or more of light in a wavelength band near 400 to 430 nm and light in a wavelength band near 680 to 700 nm are allowed to pass through each lens and each mirror reaching the element. As a result, the y value of the chromaticity of the NW on the screen is lowered and the x value is increased.
FIG. 6 is a chromaticity change diagram in the white CIE color system for explaining an embodiment of the present invention, where the horizontal axis indicates the x value and the vertical axis indicates the y value.
In the figure, a characteristic curve 35 represents a black body radiation line. In the conventional projection display apparatus, the chromaticity of NW (normal white) on the screen is, for example, a hatched portion 36 in the figure. The chromaticity of the NW on the screen in one embodiment of the present invention in which the wavelength range is manipulated as shown in FIG. 5 for the total spectral characteristics of all optical components is, for example, the shaded portion 37 in the figure. As shown in FIG. 6, the shaded portion 37 is closer to the black body radiation line 35 than the shaded portion 36, indicating that it is closer to the standard white color.
FIG. 7 is a spectral characteristic diagram showing a first embodiment of the color separation system of the video display device according to the present invention, where the horizontal axis represents the light wavelength λ (unit: nm) and the vertical axis represents the percentage of the light intensity S ( %).
FIG. 7A shows the spectral characteristics of the G reflection and B transmission type dichroic mirror 27. The dichroic mirror 19 shown in FIG. 3 is a short wave path filter, and the wavelength at which the transmittance is 50% is set to a predetermined value of 490 to 550 nm, for example, 520 nm. Accordingly, light having a wavelength of 520 nm or less enters the B optical path, and light having a wavelength exceeding 520 nm enters the G optical path. Next, FIG. 7B shows spectral characteristics of the dichroic mirror 24B. The dichroic mirror 24B is a short wave pass filter, and sets the wavelength at which the transmittance is 50% to a predetermined value between 450 and 530 nm, for example, 500 nm. Accordingly, light having a wavelength of 500 nm or less among light having a wavelength of 520 nm or less that has entered the B optical path is transmitted, and light having a wavelength of 520 nm or less is reflected and discharged from the optical path. As a result, light in an arbitrary wavelength band in the vicinity of 450 nm to 550 nm, in this case, 500 to 520 nm can be discharged from the optical path, and the y value of chromaticity in NW can be lowered.
FIG. 8 is a spectral characteristic diagram showing a second embodiment of the color separation system of the video display device according to the present invention, where the horizontal axis represents the light wavelength λ (unit: nm) and the vertical axis represents the percentage of the light intensity S ( %). FIG. 8A shows the spectral characteristics of the G reflection and B transmission type dichroic mirror 27. The dichroic mirror 27 is a short wave pass filter, and a wavelength at which the transmittance is 50% is set to a predetermined value of 450 to 530 nm, for example, 500 nm. Accordingly, light of 500 nm or less enters the B optical path, and light having a wavelength exceeding 500 nm enters the G optical path. FIG. 8B shows the spectral characteristics of the dichroic mirror 24G. The dichroic mirror 24G is a band-pass filter, and sets a wavelength with a transmittance of 50% to predetermined values of 500 to 550 nm and 570 to 600 nm, for example, 520 nm and 580 nm. Therefore, among the light having a wavelength of 500 nm or more incident on the G optical path, the light having the wavelength of 520 nm or more and 580 nm or less is transmitted and is incident on the light valve element 13G, but the light having a wavelength of less than 520 nm is reflected from the optical path. Excluded.
As a result, light in an arbitrary wavelength region in the vicinity of about 450 nm to 550 nm can be discharged from the optical path, and the y value of NW chromaticity can be lowered.
FIG. 9 is a spectral characteristic diagram showing a third embodiment of the color separation system of the video display device according to the present invention, wherein the horizontal axis indicates the wavelength of light λ (unit: nm), and the vertical axis indicates the percentage of the light intensity S ( %). FIG. 9A shows the spectral characteristics of the G reflection / B transmission dichroic mirror 27. The wavelength at which the transmittance of the dichroic mirror 27 is 50% is set to a predetermined value of 450 to 530 nm, for example, 500 nm. FIG. 9B shows the spectral characteristics of the dichroic mirror 24G. The 50% transmittance wavelength of the dichroic mirror 24G is set to a predetermined value of 500 to 550 nm, for example, 520 nm. As a result, in the case of the selected setting value, light in the wavelength range from 500 nm to 520 nm can be discharged from the optical path, and in the case of the widest range, light of about 480 to 550 nm can be discharged from the optical path. Y value can be lowered.
The transmission characteristics of the dichroic mirrors 19, 24B, 27, and 24G described with reference to FIGS. 7, 8, and 9 are partially changed, for example, by changing the dielectric material, the film thickness, or the angle at which the vapor is applied when depositing the film. It can be set by various methods such as changing the film thickness.

It is a schematic diagram which shows the 1st, 2nd Example of the video display apparatus by this invention. It is a top view of a color filter. It is a schematic diagram which shows the 3rd Example of the video display apparatus by this invention. It is a spectral characteristic figure of the light source used for the video display apparatus by this invention. It is a characteristic view which shows one Example of the spectral characteristic of the whole optical component of the video display apparatus shown in FIG. It is a chromaticity change figure in the white CIE color system for demonstrating one Example of this invention. It is a spectral characteristic figure which shows the 1st Example of the color separation system of the video display apparatus by this invention. It is a spectral characteristic figure which shows the 2nd Example of the color separation system of the video display apparatus by this invention. It is a spectral characteristic figure which shows the 3rd Example of the color separation system of the video display apparatus by this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light source, 2 ... Reflector, 3 ... Illumination system, 4A, 4B ... Light valve element, 5 ... Color filter, 6 ... Projection lens, 7 ... Screen, 9 ... Lamp, 10 ... Reflector, 11 ... Lamp unit, 12 ... First array lens, 13R, 13G, 13B ... Liquid crystal display element, 14 ... Second array lens, 15 ... Polarizing beam splitter, 16 ... λ / 2 phase difference plate, 17 ... Condenser lens, 18 ... Total reflection mirror, DESCRIPTION OF SYMBOLS 19 ... B light, G light reflection dichroic mirror, 20 ... Red light reflection mirror, 22 ... Incident side polarizing plate, 23 ... Outgoing side polarizing plate, 24 ... Dichroic mirror, 25 ... Dichroic prism, 26 ... Projection lens, 27 ... G light reflection type dichroic mirror.

Claims (3)

A light source that emits light having a maximum output wavelength in the range of 540 nm to 560 nm;
Color separation means for separating light emitted from the light source into a plurality of color lights;
A light valve element that modulates light from the color separation means based on a video signal;
Projection means for projecting light modulated by the light valve element;
An image display comprising: an exclusion unit that excludes at least a light having a wavelength in a range of 500 nm to 520 nm and a wavelength in a range of 580 nm to 600 nm among the light from the color separation unit, and transmits the remaining light. apparatus. The video display device according to claim 1,
The image display device according to claim 1, wherein the exclusion means is arranged in the vicinity of the incident side of the light valve element. The video display device according to claim 1 or 2,
The video display device, wherein the color separation unit and the exclusion unit are color filters that time-divide light emitted from the light source.

Images