JP2000039583A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the installation area of a liquid crystal projector small, to make the length of respective color optical paths equal in a color resolving optical system and to eliminate the need of an optical device for correcting it by three-dimensionally arranging the color resolving optical system and a color synthesis optical system. SOLUTION: A prism 5 is in a hexahedron shape (rectangular parallelopiped shape) and an R reflection film 3 making white light from a lamp 2 incident from a 1st surface 5a and reflecting only red light and a B reflection film 4 making the white light incident and reflecting only blue light are arranged to be X-shaped inside. Reflection mirrors 7 and 8 reflect the light reflected by the film 3 and emitted from the 2nd surface 5b of the prism 5 and make it incident on the 2nd surface 5b of the prism 5 again. Reflection mirrors 13 and 14 reflect the light reflected by the film 4 and emitted from the 4th surface 5d of the prism 5 and make it incident on the 4th surface 5d of the prism 5 again. Reflection mirrors 10 and 11 reflect the light passing through the films 3 and 4 and emitted from the 3rd surface 5c of the prism 5 and make it incident on the 3rd surface 5c of the prism 5 again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention decomposes a white light beam from a light source into light beams of three colors of red, blue and green, and modulates each of these color light beams through a liquid crystal panel in accordance with video information.
The present invention relates to a projection display device such as a liquid crystal projector that recombines modulated light fluxes of each color after modulation and projects the enlarged light onto a screen via a projection lens.

[0002]

2. Description of the Related Art In recent years, as a liquid crystal projector as a projection display device, a small, high-resolution liquid crystal panel has been put into practical use, and a liquid crystal projector using the same has been required to be smaller. ing.

Hereinafter, a liquid crystal projector as a conventional projection display device will be described. FIG. 5 is a plan view showing an arrangement of optical elements in an optical unit 101 of a conventional liquid crystal projector. The optical unit 101 includes a lamp 102 as a light source and a reflection mirror 103 disposed at an angle of about 45 degrees in an optical path and reflecting light from the lamp 102.
And a B-transmitting dichroic mirror 104 that is disposed at an angle of about 45 degrees in the optical path, transmits only blue light, and reflects other light, and is disposed at an angle of about 45 degrees in the optical path.
A reflection mirror 105 for reflecting light transmitted through the transmission dichroic mirror 104; a G reflection dichroic mirror 106 disposed at an angle of about 45 degrees in the optical path for reflecting only green light and transmitting the other light; Reflecting mirrors 107 and 108 for reflecting light transmitted through the reflecting dichroic mirror 106, and these reflecting mirrors 10
7 and 108, a relay lens 109 for correcting the optical path length, and a liquid crystal panel 110R, 110 corresponding to red, green, and blue image information and capable of modulating each pixel.
G, 110B and their liquid crystal panels 110R, 110
G, 110B, the field lenses 111R, 111G, 111B attached immediately before the liquid crystal panel 110
A hexahedral color synthesis prism 112 that recombines the red, green, and blue light modulated by R, 110G, and 110B and emits light in a predetermined direction, and outputs the light emitted from the color synthesis prism 112 to an external screen Projection lens 1 for projection
13.

The operation of the liquid crystal projector configured as described above will be described below. First, white light emitted from a lamp 102 as a light source is separated into blue light when reflected by a B transmission dichroic mirror 104, green light is separated when passing through a G dichroic mirror 106, and the rest is red light Only be. That is, the white light from the lamp 102 is decomposed into red, green, and blue light.

[0005] Each of the decomposed lights is applied to a liquid crystal panel 1.
When transmitting through 10R, 110G, and 110B, it is modulated for each pixel based on image information. Then, the color synthesis prism 1
At 12, the red, green and blue lights are recombined and enlarged and projected by a projection lens 113 onto a screen (not shown).

[0006]

However, in the above conventional configuration, the B-transmitting dichroic mirror 104, G
Reflection dichroic mirror 106, reflection mirror 103,
The color separation optical system consisting of 105, 107 and 108 is arranged in a plane separately from the color synthesis optical system consisting of the color combining prism 112, which has a problem that the installation area of the liquid crystal projector becomes large. . Further, since the optical path length of only one color in the color separation optical system and only red light in the conventional example is long, an optical element such as a relay lens 109 for correcting so as to eliminate the influence of the optical path length is required, and cost is reduced. There is a problem that the screen brightness is reduced due to the increase in light and loss of light by the optical elements.

The present invention solves the above problems, and provides a projection type display device in which the installation area of a liquid crystal projector is small, the optical path length of each color is equal in a color separation optical system, and no optical element for correction is required. The purpose is to do.

[0008]

In order to achieve this object, a projection type display device according to the present invention has a hexahedral shape, and a white light incident from a first surface which is one of four surrounding surfaces. And red light, green light and blue light are respectively emitted from the second surface of the three surfaces other than the first surface out of the four surfaces, and the light is emitted from the second surface. A reflection that combines the incident red light, the green light incident from the third surface, and the blue light incident from the fourth surface, emits the light to the first surface, and reflects or transmits only light in a specific wavelength range. A prism having a film disposed therein in an X shape, a light source for irradiating the first surface of the prism with white light, a red light emitted from the second surface of the prism, and a green light emitted from the third surface And the blue light emitted from the fourth surface is reflected, and again reflected on the second, third, and fourth surfaces of the prism. A plurality of reflecting mirrors to be projected, three liquid crystal panels located between the reflecting mirror and the prism, and capable of modulating each of red light, green light, and blue light for each pixel based on information; And a projection lens for projecting light emitted from the first surface and superimposing and forming images of the three liquid crystal panels on a screen.

With this configuration, it is possible to provide a projection type display device in which the installation area of the liquid crystal projector is small, the optical path length of each color is equal in the color separation optical system, and no optical element for correction is required.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The projection type display device according to the first aspect of the present invention has a hexahedral shape, and has one of four peripheral surfaces.
White light incident from the first surface, which is the
Red light from the second surface of the three surfaces other than the first surface,
Green light from the surface, blue light from the fourth surface, and red light incident from the second surface, green light incident from the third surface, and blue light incident from the fourth surface. First
A prism in which a reflection film that emits to the surface and reflects only light in a specific wavelength range or transmits the light is disposed in an X-shape,
The light source irradiates the first surface of the prism with white light, reflects the red light emitted from the second surface of the prism, the green light emitted from the third surface, and the blue light emitted from the fourth surface. Again, a plurality of reflecting mirrors that are incident on the second, third, and fourth surfaces of the prism, and are located between the reflecting mirror and the prism; Three liquid crystal panels each of which can be modulated for each pixel based on information;
A projection lens for projecting light emitted from the first surface of the prism and superimposing the images of the three liquid crystal panels on a screen to form an image. Separation of red, green and blue light from
It is possible to combine red light, green light and blue light with one prism, so that it is possible to reduce the installation area and to make the optical path of each color equal. .

The projection display device according to a second aspect of the present invention has a hexahedral shape, separates white light incident from the first surface, which is one of the four surrounding surfaces, and converts the white light into the surrounding four light. Red light, green light, and blue light are emitted from the second, third, and fourth surfaces of the three surfaces other than the first surface, respectively, to reflect or transmit only light in a specific wavelength range. A first prism in which a reflection film is arranged in an X-shape and a hexahedral shape;
The red light incident from the second surface of the four surrounding surfaces and the third light
The green light incident from the surface and the blue light incident from the fourth surface are combined, and the light is emitted to the first surface, which is the remaining one of the four surrounding surfaces, and only the light in the specific wavelength range is emitted. A second prism in which a reflective film that reflects or transmits is arranged in an X-shape, a light source that irradiates a first surface of the first prism with white light, and a second surface of the first prism , The green light emitted from the third surface, and the blue light emitted from the fourth surface are reflected on the second, third, and fourth surfaces of the second prism. A plurality of reflecting mirrors to be incident, and three liquid crystal panels located between the reflecting mirror and the second prism and capable of modulating each of red light, green light, and blue light for each pixel based on information; Projecting the light emitted from the first surface of the second prism, and superimposing the images of the three liquid crystal panels on a screen. Awashi and which is characterized in that a projection lens for forming a prism for performing the red light, green light, blue light separating from the white light, red light,
Using a prism that synthesizes green light and blue light, it is possible to reduce the installation area and to have an effect that it is possible to equalize the optical path of each color,
It is also possible to use two in a pile.

Further, a prism may be used instead of the reflecting mirror. Hereinafter, embodiments of the present invention will be described with reference to FIGS. (Embodiment 1) FIG. 1 is a plan view of an optical unit 1 of a liquid crystal projector as a projection display according to an embodiment of the present invention, and FIG. 2 is a perspective view.

As shown in FIGS. 1 and 2, an optical unit 1 of a liquid crystal projector has a lamp 2 as a light source, a hexahedral shape (a rectangular parallelepiped shape), and a white light from the lamp 2 as a first light.
A prism 5 in which an R-reflecting film 3 that reflects from the surface 5a and reflects only red light and a B-reflecting film 4 that reflects only blue light are arranged in an X shape inside, and a prism 5 that is reflected by the R-reflecting film 3 The reflecting mirrors 7 and 8 reflect the light emitted from the second surface 5b of the prism 5 and make the light incident on the second surface 5b of the prism 5 again.
And the prism 5 passing through the R reflection film 3 and the B reflection film 4
Reflecting mirrors 10 and 11 for reflecting the light emitted from the third surface 5c of the prism 5 and causing the light to enter the third surface 5c of the prism 5 again;
The reflecting mirrors 13 and 14 reflect the light reflected by the reflection film 4 and emitted from the fourth surface 5d of the prism 5, and then make the light enter the fourth surface 5d of the prism 5 again. Liquid crystal panels 15R, 15G, 15B arranged in
And the light emitted from the prism 5 is projected on an external screen (not shown), and the liquid crystal panels 15R, 15G, and 15B are projected.
And a projection lens 16 for forming an image on the screen.

The operation of the projection type display device configured as described above will be described. First, the white light emitted from the lamp 2 enters the prism 5, and the red light has its optical path bent at right angles by the R reflection film 3, and is emitted out of the prism 5 from the second surface 5 b of the prism 5, The blue light is bent at right angles in the opposite direction to the red light by the B reflection film 4, and is emitted from the fourth surface 5 d of the prism 5 to the outside of the prism 5. The remaining green light passes through the R reflection film 3 and the B reflection film 4 and is emitted from the third surface 5c of the prism 5,
In this way, white light is decomposed into red, green, and blue light.

The light of each color emitted from the prism 5 is again irradiated by the reflecting mirrors 7, 8, 10, 11, 13, 14 (the second surface 5b, the fourth surface 5d and the fourth surface 5d). It is folded back toward the three surfaces 5c). On the way, in each optical path, liquid crystal panels 15R, 15G as shutters, which can be modulated for each pixel based on image information,
15B, the light of each color enters the prism 5 in a modulated state.

The red light incident on the prism 5 from the second surface 5b of the prism 5 is bent in a right angle direction by the R reflection film 3, and emitted from the first surface 5a of the prism 5 in a direction in which the white light is incident. The blue light incident on the prism 5 from the fourth surface 5d of the prism 5 is bent at a right angle by the B reflection film 4, and the first surface 5 of the prism 5 is moved in the direction in which the white light is incident.
a. The green light entering from the third surface 5c of the prism 5 passes through the R reflection film 3 and the B reflection film 4, and is emitted from the first surface 5a of the prism 5 in a direction in which white light is incident. Thus, the liquid crystal panels 15R, 15G,
The light of each color modulated by 15B is emitted after being recombined by the prism 5 and projected on an external screen by the projection lens 16.

As described above, according to the present embodiment, 1
With the two prisms 5, color separation and color synthesis can be performed, and the optical unit 1 including a small optical system can be obtained.
In addition, since the color separation optical system and the color synthesis optical system are three-dimensionally arranged, all the position adjustment mechanisms of the liquid crystal panel can be integrated in a narrow range, and the installation area of the liquid crystal projector can be reduced. . In addition, since the optical path lengths of all the colors are equal, a lens for correction is not required on the way, the manufacturing cost is reduced accordingly, and the screen brightness is reduced due to light loss due to the lens for correction as in the conventional case. The problem does not arise.

(Embodiment 2) FIG. 3 is a perspective view of an optical unit 21 of a liquid crystal projector as a projection type display apparatus according to another embodiment of the present invention.

The optical unit 21 of this liquid crystal projector
Denotes a lamp 22 as a light source, a hexahedral shape (a rectangular parallelepiped shape), in which white light from the lamp 22 is incident from a first surface 25a, and an R reflection film 23 that reflects only red light and a B reflection that reflects only blue light. A first prism 25 in which a film 24 is arranged in an X shape inside, and an R reflection which is located on the first prism 25 and has a hexahedral shape (a rectangular parallelepiped shape) and internally reflects only red light. A second prism 39 in which a film 37 and a B reflection film 38 that reflects only blue light are arranged in an X shape
The reflecting mirrors 27 and 28 reflect the light reflected by the R reflection film 23 and emitted from the second surface 25b of the first prism 25, and enter the second surface 39b of the second prism 39.
And a reflecting mirror 30 that reflects light emitted from the third surface 25c of the first prism 25 through the R reflection film 23 and the B reflection film 24 and makes the light incident on the third surface 39c of the second prism 39. , 31 and light reflected by the B reflection film 24 and emitted from the fourth surface 25d of the first prism 25, and
Reflecting mirrors 33 and 34 for entering the fourth surface 39d of the second prism 39, liquid crystal panels 35R, 35G and 35B disposed in the optical path of the re-entering light, and the prism 3
The projection lens 36 projects the light emitted from the LCD 9 onto an external screen (not shown) and forms images of the liquid crystal panels 35R, 35G, and 35B on the screen.

The difference from the configuration of the optical unit 1 shown in FIG. 2 is that the optical unit 1 shown in FIG. And two second prisms 39 which are the same.

The operation of the projection display device having the above-described configuration will be described. First, the white light emitted from the lamp 22 is incident on the first prism 25, and the red light is bent at a right angle by the R reflection film 23 in the optical path.
The blue light is emitted from the second surface 25 b of the first prism 25 to the outside of the first prism 25, and the blue light is bent by the B reflection film 24 at a right angle in the opposite direction to the red light. The light is emitted from the four surfaces 25d to the outside of the first prism 25. The remaining green light is transmitted through the R reflection film 23 and the B reflection film 24, and becomes the third surface 25c of the first prism 25.
And the white light is thus decomposed into red, green and blue light.

The light of each color emitted from the first prism 25 is reflected by the reflecting mirrors 27, 28, 30, 31, 33, and 34 to act on the second surface 39b and the fourth surface 39 of the second prism 39.
d and the third surface 39c are folded back in each direction. On the way,
In each optical path, liquid crystal panels 35R, 35G, and 3 as shutters that can be modulated for each pixel based on image information.
Since 5B is arranged, the light of each color enters the second prism 39 in a modulated state.

The red light that has entered the second prism 39 from the second surface 39b of the second prism 39 is bent in a right angle direction by the R reflection film 37, and is bent in the direction in which the white light has entered. Of the second prism 39 from the fourth surface 39d of the second prism 39.
The blue light incident on 9 is bent at a right angle by the B reflection film 38 and emitted from the first surface 39a of the second prism 39 in the direction in which the white light is incident. Also, the second prism 39
The green light incident from the third surface 39c passes through the R reflection film 37 and the B reflection film 38, and is emitted from the first surface 39a of the second prism 39 in the direction in which the white light is incident. In this manner, the light of each color modulated by the liquid crystal panels 35R, 35G, and 35B is emitted after being recombined by the second prism 39, and is projected on an external screen by the projection lens 36.

As described above, according to this embodiment, color separation and color synthesis can be performed by using two prisms similar to those conventionally used for color synthesis,
The optical unit 21 including a small optical system can be obtained, and the color separation optical system and the color synthesis optical system are three-dimensionally arranged. And the installation area of the liquid crystal projector can be reduced. In addition, since the optical path lengths of all the colors are equal, a lens for correction is not required on the way, the manufacturing cost is reduced accordingly, and the screen brightness is reduced due to light loss due to the lens for correction as in the conventional case. The problem does not arise.

In the above description, the prisms 5, 25
The mirrors 7, 8, 10, 11, 13, 14, 27, 28, 30, which are pairs of light emitted from
The light was again incident on the prisms 5 and 39 by using 31, 33 and 34. However, as shown in FIG.
10, 11, 13, 14, 27, 28, 30, 31, 3
The triangular prisms 51, 52, and 53 can be substituted for 3, 34.

[0026]

As described above, according to the present invention, since the color separation optical system and the color synthesizing optical system are three-dimensionally arranged, all the position adjustment mechanisms of the liquid crystal panel can be integrated in a narrow range. Thus, there is an excellent effect that it can be used for a small liquid crystal projector having a small space near the liquid crystal panel. In addition, since the optical path length of each color can be equalized in the color separation optical system, an optical element for correcting the optical path length becomes unnecessary, and the manufacturing cost is reduced accordingly, and the light loss due to the correction lens as in the related art is reduced. Therefore, there is no problem that the screen luminance is reduced due to this.

[Brief description of the drawings]

FIG. 1 is a plan view of an optical unit of a liquid crystal projector according to Embodiment 1 of the present invention.

FIG. 2 is a perspective view of an optical unit of the liquid crystal projector according to the first embodiment.

FIG. 3 is a perspective view of an optical unit of the liquid crystal projector according to Embodiment 2 of the present invention.

FIG. 4 is a perspective view of an optical unit of a liquid crystal projector showing another embodiment of the present invention.

FIG. 5 is a plan view of an optical unit of a conventional liquid crystal projector.

[Explanation of symbols]

 1, 21 optical unit 2, 22 lamp 3, 23, 37 R reflection film 4, 24, 38 B reflection film 5 prism 5a, 25a, 39a First surface 5b, 25b, 39b Second surface 5c, 25c, 39c Third surface 5d, 25d, 39d Fourth surface 7, 8, 10, 11, 13, 14, ... Reflector 15R, 15G, 15B Liquid crystal panel 16, 36 Projection lens 25 First prism 27, 28, 30, 31, 33, 34 Reflector 35R, 35G, 35B ..Liquid crystal panel 39: second prism 51, 52, 53 ... prism

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 9/31 H04N 9/31 C (72) Inventor Shoji Kawahara 1006 Kazuma, Kazuma, Kazuma, Osaka Matsushita Electric Industrial Incorporated F term (reference) 2H088 EA14 HA13 HA23 HA24 HA28 MA20 5C058 AB06 BA35 EA11 EA12 EA13 EA26 EA51 5C060 BC05 DA04 GA02 HC10 HC11 HC20 HC25 JB06

Claims (4)

[Claims] 1. A hexahedral shape, wherein one of four surrounding surfaces is provided.
White light incident from the first surface, which is the
Red light from the second surface of the three surfaces other than the first surface,
Green light from the surface, blue light from the fourth surface, and red light incident from the second surface, green light incident from the third surface, and blue light incident from the fourth surface. First
A prism having an X-shaped reflecting film that emits light to a surface and reflects or transmits only light in a specific wavelength range, an X-shaped light source, and a light source that irradiates a first surface of the prism with white light; The red light emitted from the second surface, the green light emitted from the third surface, and the blue light emitted from the fourth surface are reflected, and the second surface, the third surface, and the fourth surface of the prism are again reflected. A plurality of reflecting mirrors to be incident on the surface, and three liquid crystal panels located between the reflecting mirror and the prism and capable of modulating each of red light, green light, and blue light for each pixel based on information; and A projection lens for projecting light emitted from the first surface of the prism and superimposing and forming images of the three liquid crystal panels on a screen. 2. A hexahedral shape, wherein one of four surrounding surfaces is provided.
White light incident from the first surface, which is the
Red light from the second surface of the three surfaces other than the first surface,
A first prism in which a reflecting film that emits green light from the surface and blue light from the fourth surface and reflects or transmits only light in a specific wavelength range is disposed in an X-shape, and a hexahedral shape And the red light incident from the second surface of the four surrounding surfaces, the green light incident from the third surface, and the blue light incident from the fourth surface are combined, and the four surrounding surfaces are combined. A second prism in which a reflection film that emits to the first surface, which is the remaining one surface, and reflects or transmits only light in a specific wavelength range is disposed in an X-shape, and the first prism A light source for irradiating the first surface with white light; a red light emitted from the second surface of the first prism; a green light emitted from the third surface; and a blue light emitted from the fourth surface. A plurality of reflecting mirrors that are incident on second, third, and fourth surfaces of the second prism; Three liquid crystal panels positioned between the second prism and capable of modulating each of red light, green light, and blue light for each pixel based on information; and emitting from the first surface of the second prism. And a projection lens for projecting the reflected light and superimposing the images of the three liquid crystal panels on a screen to form an image. 3. The projection display device according to claim 2, wherein the first prism and the second prism are arranged in a stacked state. 4. The projection type display device according to claim 1, wherein a prism is used instead of the reflecting mirror.