JPH0695060A - Projection display device - Google Patents

Abstract

(57) [Summary] [Object] With regard to a projection display device, linearly polarized light emitted from a spectral optical member for color separation can be rotated with respect to a light valve without using a half-wave plate, or It is an object of the present invention to rotate linearly polarized light emitted from a bulb so that the linearly polarized light can enter the color combining optical member. A light source 10, spectroscopic optical members 12, 14, 16 for splitting the light of the light source, light valves 18, 20, 22 for spatially modulating the split light, and a display for displaying the spatially modulated light And the light valves 18, 20,
22 has a horizontal line of display and is formed to receive linearly polarized light in a vibration direction oblique to the horizontal line of display (72), and the light source, the spectroscopic optical member, and the light valve include The incident surface 34 of the optical member and the vibration direction of the linearly polarized light received by the light valve are arranged so as to be parallel or orthogonal to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device for displaying light image-modulated by a light valve on a screen.

[0002]

2. Description of the Related Art In recent years, a projection type display device using a liquid crystal panel as a light valve has been developed. Many liquid crystal panels use twisted nematic liquid crystals, and an alignment film is provided on each of a pair of transparent substrates sandwiching the liquid crystal, and these alignment films are rubbed in mutually orthogonal directions. Further, a polarizer is arranged on the light incident side of the liquid crystal panel, and an analyzer is arranged on the light emitting side of the liquid crystal panel.

In a projection display device for color display, as shown in FIG. 4, the light of a light source 50 is split by dichroic mirrors 52, 54 and 56 for color separation, and the split light is composed of a plurality of liquid crystal panels. Light valves 58, 60,
The image light of each color spatially modulated by 62 is projected onto the screen 7 by the respective projection lenses 64, 66, 68.
0 is projected, and each color is combined and displayed on this screen. Alternatively, when the number of projection lenses is one, the image lights of the respective colors spatially modulated by a plurality of liquid crystal panels are combined by the dichroic mirror for color combination, and the combined light is projected on the screen by the projection lens to be displayed. It is supposed to do.

The screen 70 is often formed in a horizontally long rectangular shape, and therefore the light valves 58, 60 ,.
62 is also formed in a horizontally long rectangular shape, and has a screen 70.
It is arranged corresponding to. 3 light valves 58, 6
0 and 62 are arranged side by side in the horizontal direction. It is known that a projection-type display device using liquid crystal has viewing angle characteristics depending on the alignment direction of the liquid crystal. As shown in FIG. 4, when the three light valves 58, 60, 62 are arranged side by side in the lateral direction, the respective light valves 58, 60,
It is known that when the alignment film 62 is rubbed as shown in FIG. 5, the color unevenness of the mixed color on the screen 70 is minimized.

In FIG. 5, the rubbing direction of the alignment film of the substrate on the light incident side of the pair of substrates sandwiching the liquid crystal is indicated by a dashed arrow 72, and the rubbing direction of the alignment film of the substrate on the light emitting side is shown. The rubbing direction is indicated by the solid arrow 74. The rubbing directions shown by arrows 72 and 74 are both
The angle is 45 degrees with respect to the long side and the short side of the liquid crystal panel. The transmission axes of the polarizer and the analyzer on both sides of the liquid crystal panel are arranged so as to match their rubbing directions.

[0006]

The dichroic mirrors 52, 54 and 56 are arranged at an angle of 45 degrees with respect to the light valves 58, 60 and 62, and reflect the light of a specific wavelength band to associate with the light valves. The light of the remaining wavelength band is transmitted and directed to the next dichroic mirror. Dichroic mirror 5
In the designs of 2, 54, and 56, either P-polarized light or S-polarized light is mainly designed. For example, the dichroic mirror 52 is designed to reflect light in a specific wavelength band of P-polarized light and transmit light in the remaining wavelength band.
The P-polarized light has a vibration direction parallel to the incident surface, and the S-polarized light has a vibration direction orthogonal to the incident surface.

Therefore, when the vibration direction of the P-polarized light reflected by the dichroic mirror 52 matches the transmission axis of the polarizer of the light valve 58 and the rubbing direction of the alignment film, the color purity is improved and the amount of light is reduced. It is convenient because it can be kept high. However, conventionally, the dichroic mirror 5
2, 54, 56 and light valves 58, 60, 62,
The projection lenses 64, 66 and 68 were in the same horizontal plane. Therefore, the incident surface of the dichroic mirror 52 is in the horizontal plane, and the vibration direction of the P-polarized light reflected by the dichroic mirror 52 is parallel to the horizontal long side of the light valve 58. That is, in FIG. 5, it is parallel to the upper side 73. When S-polarized light is used, it is parallel to the vertical short side of the light valve 58. In any case, the diagonal rubbing directions 72 and 74 in FIG. 5 are not coincident with or parallel to each other.

Therefore, as a conventional technique, a half-wave plate is inserted between the dichroic mirror 52 and the light valve 58, and the P-polarized light or the S-polarized light reflected by the dichroic mirror 52 is rotated by 45 degrees and made incident on the light valve 58. I have a suggestion. However, when the half-wave plate is inserted, there is a problem that the polarization is disturbed and the amount of transmitted light is reduced.

Further, even in the case of a structure including a dichroic mirror for color combination, if the rubbing direction of the light valve 58 and the transmission axis of the analyzer are inclined, the outgoing polarized light of the light valve 58 is for color combination. The light enters the dichroic mirror and is reflected excessively, resulting in a loss of light amount, or multiple reflections causing a ghost. As a countermeasure, it is conceivable to insert a half-wave plate, but in this case, there is a problem in that the resolution is lowered.

It is an object of the present invention to rotate linearly polarized light emitted from a spectral optical member for color separation with respect to a light valve without using a half-wave plate, or to linearly polarized light emitted from a light valve. It is an object of the present invention to provide a projection type display device capable of rotating a light beam and making it enter a color combining optical member.

[0011]

A projection type display device according to the present invention comprises a light source 10, spectroscopic optical members 12, 14, 16 for separating the light of the light source, and a light valve 18 for spatially modulating the separated light. , 20, 22 and a display unit for displaying spatially modulated light, and the light valves 18, 20, 2 are provided.
2 has a horizontal line of display and is formed so as to receive linearly polarized light in a vibration direction oblique to the horizontal line of display (72), and the light source, the spectroscopic optical member, and the light valve include The incident surface 34 of the optical member and the vibration direction of the linearly polarized light received by the light valve are arranged so as to be parallel or orthogonal to each other. Further, the projection display device according to the present invention includes a light source 10, a plurality of light valves 18, 20, 22 for spatially modulating the light of the light source,
A combining optical member 40 for combining a plurality of spatially modulated lights,
42, and a display unit for displaying light that has passed through the synthetic optical member. The light valve has a horizontal line for display and is configured to emit linearly polarized light in a vibration direction oblique to the horizontal line for display. And the light valve and the synthetic optical member are arranged such that a vibration direction of outgoing linearly polarized light of the light valve and an incident surface of the synthetic optical member are parallel or orthogonal to each other. To do.

[0012]

In the above structure, the light source and the spectroscopic optical member are rotated with respect to the light valve,
The incident surface of the spectroscopic optical member and the vibration direction of the linearly polarized light received by the light valve are arranged so as to be parallel or orthogonal to each other. In this case, the vibration direction of the linearly polarized light received by the light valve is oblique. In another configuration, the light valve and the combining optical member are arranged such that the vibration direction of the outgoing linearly polarized light of the light valve and the incident surface of the combining optical member are parallel or orthogonal to each other. Also in this case, the light valve is arranged so as to emit the linearly polarized light in the oblique vibration direction.

[0013]

FIG. 1 is a diagram showing a first embodiment of the present invention.
The projection display device includes a light source 10, color separation dichroic mirrors 12, 14, 16 and three light valves 1.
8, 20, 22 and three projection lenses 24, 26, 28
And a screen (see FIG. 4). The color separation dichroic mirrors 12, 14, 16 are composed of a liquid crystal panel in which twisted nematic liquid crystal is sealed in a pair of transparent substrates (not shown), and a polarizer and an analyzer on both sides of the liquid crystal panel.

Each of these substrates has a horizontally long rectangular shape, and an electrode and an alignment film are provided on the inner surface of each substrate. As shown in FIG. 5, for example, the alignment film of the substrate on the light incident side is rubbed in the direction shown by the broken arrow 72,
The alignment film of the substrate on the light emitting side is rubbed in the direction indicated by the solid arrow 74. Both rubbing directions indicated by arrows 72 and 74 are 4 with respect to the long side and the short side of the liquid crystal panel.
The angle is 5 degrees. The transmission axes of the polarizer and the analyzer on both sides of the liquid crystal panel are arranged so as to match their rubbing directions.

In FIG. 1, the rubbing direction of the alignment film of the substrate on the light incident side is shown by an arrow 72. The rubbing direction of the alignment film on the substrate on the light emission side is perpendicular to this. That is, the light valves 18, 20, 22 are formed so as to receive linearly polarized light in a vibration direction oblique to the center horizontal line of the light valve.

The dichroic mirror 12 reflects, for example, a green (G) color light component toward the light valve 18 and transmits the remaining light component. The dichroic mirror 14 reflects the red (R) color light component toward the light valve 20, and transmits the remaining light component. The dichroic mirror 16 reflects the blue (B) light component toward the light valve 22. However, the arrangement of the color separation dichroic mirror can be changed.
The projection lenses 24, 26 and 28 display images on the screen similar to those in FIG.

As shown in FIGS. 1 and 2, the dichroic mirrors 12, 14, 16 and the light valve 18,
20, 22 (and projection lenses 24, 26, 28) are in the same plane, but this plane is inclined with respect to the horizontal plane. That is, as shown in FIG. 2, the light valves 18, 20, and 22 are arranged in the same vertical plane so that the light valves rise upward to the left. The dichroic mirrors 12, 14 and 16 are similarly arranged in the upward left direction corresponding to the associated light valves 18, 20, and 22.

Further, the dichroic mirrors 12, 1
4, 16 are arranged at an angle of 45 degrees with respect to the associated light valves 18, 20, 22 as shown in FIG. 4, and while maintaining this 45 degree angle, each light valve 18, 20 , 22 more about the optical axis of 22
Is rotated once. Light source 10 to each dichroic mirror 1
The incident optical axis 30 extends straight through 2, 14, 16
A reflection optical axis 32 from each dichroic mirror 12, 14, 16 extends toward each light valve 18, 20, 22. The incident surface 34 of the dichroic mirrors 12, 14, 16 is a plane including the incident optical axis 30 and the reflected optical axis 32 (or the refracted optical axis).

As a result, according to the present invention, the incident surface 34 of the dichroic mirrors 12, 14, 16 and the light valve 1 are arranged.
The vibration directions of the linearly polarized light received by 8, 20, and 22 (the transmission axis direction of the polarizer and the rubbing direction of the alignment film of the substrate) are parallel or orthogonal to each other. Therefore, in the present invention, the P-polarized light (or S-polarized light) of a specific band reflected by the dichroic mirrors 12, 14, 16 is almost directly transmitted through the polarizer and used by the light valves 18, 20, 22, and R, G. , B have high color purity and high brightness.

FIG. 3 is a diagram showing a second embodiment of the present invention. In this example, there is one projection lens 24, and instead of this, dichroic mirrors 40 and 42 for color combination are provided. The projection display device includes a light source 10, color separation dichroic mirrors 12 and 14, a total reflection mirror 36,
38, three light valves 18, 20, and 22, dichroic mirrors 40 and 42 for color combination, a projection lens 24, and a screen (see FIG. 4). While the three light valves 18, 20, 22 in FIG. 1 are arranged side by side, the light valves 18, 20 in FIG. 3 are arranged so that the emitted light is transmitted and reflected by the dichroic mirror 40 for color combination. The light valve 22 is arranged so as to be reflected by the total reflection mirror 36 and transmitted through the dichroic mirror 42 for color combination. The light coming from the color combining dichroic mirror 40 is reflected by the color combining dichroic mirror 42, and the color combined light is projected from the projection lens 24 onto the screen.

Dichroic mirrors 12 and 14 for color separation
Are the light valves 18, 20, 2 as in the case of FIG.
It is arranged at an angle of 45 degrees with respect to 2, and this 4
While maintaining the 5 degree angle, each light valve 18, 2
It is further rotated 45 degrees about the optical axes of 0 and 22.
Therefore, the P-polarized light (or S-polarized light) in the specific band reflected by the dichroic mirrors 12, 14, 16 is almost transmitted through the polarizer as it is, and the light valves 18, 20, 22 are transmitted.
The color purity of R, G and B is high and the brightness is high.

In FIG. 3, the light valves 18, 20, 22 are shown.
The rubbing direction of the alignment film of the substrate on the light incident side is indicated by arrow 72. The rubbing direction of the alignment film on the substrate on the light emission side is perpendicular to this.

Further, in the present invention, the light valve 18,
Vibration directions of emitted linearly polarized light of 20 and 22 (directions perpendicular to the arrow 72) and dichroic mirrors 40 and 42 for color combination.
Are arranged so as to be parallel or orthogonal to the incident surface of. Therefore, the dichroic mirrors 40 and 4 for color combination are used.
Only P-polarized light or S-polarized light is incident on the light beam 2, so that light loss or ghost does not occur in the color combining dichroic mirrors 40 and 42.

[0024]

As described above, according to the present invention,
The linearly polarized light emitted from the color separation spectral optical member can be rotated with respect to the light valve without using a half-wave plate, or the linearly polarized light emitted from the light valve can be rotated to generate a color combining optical member. It is possible to obtain a projection display device having high color purity and high brightness.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a rear view showing the arrangement of the light valves of FIG.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a conventional technique.

5 is a plan view showing the light valve of FIG. 4. FIG.

[Explanation of symbols]

 10 ... Light source 12, 14, 16 ... Dichroic mirror 18, 20, 22 ... Light valve 24, 26, 28 ... Projection lens 34 ... Incident surface 72 ... Rubbing direction

Front page continuation (72) Inventor Takeshi Goto 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, Fujitsu Limited (72) Inventor Yoshinori Tanaka, 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture (72) Invented Hisashi Yamaguchi 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited

Claims (3)

[Claims] 1. A light source (10), a spectroscopic optical member (12, 14, 16) for splitting the light of the light source, a light valve (18, 20, 22) for spatially modulating the split light, and a space. A display unit for displaying modulated light, wherein the light valve (18, 20, 22) has a horizontal line of display and is formed to receive linearly polarized light in a vibration direction oblique to the horizontal line of display. (72) Further, in the light source, the spectroscopic optical member, and the light valve, the incident surface (34) of the spectroscopic optical member and the vibration direction of the linearly polarized light received by the light valve are parallel or orthogonal to each other. A projection display device characterized by being arranged. 2. A light source (10), a plurality of light valves (18, 20, 22) for spatially modulating the light of the light source, and a combining optical member (40, 4) for combining the plurality of spatially modulated lights.
2) and a display unit for displaying the light that has passed through the synthetic optical member, wherein the light valve (18, 20, 22) has a horizontal line of display and a vibration direction oblique to the horizontal line of display. Configured to emit linearly polarized light, and
A projection type display characterized in that the light valve and the synthetic optical member are arranged such that a vibration direction of outgoing linearly polarized light of the light valve and an incident surface of the synthetic optical member are parallel or orthogonal to each other. apparatus. 3. The liquid crystal panel, wherein the light valve has a substantially rectangular display area having long sides and short sides, and incident linearly polarized light forms an angle of about 45 degrees with the long sides and the short sides. The projection type display device according to claim 1 or 2.