JP2001125198A - Light source for illumination and liquid crystal projector using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source for illumination and a liquid crystal projector using the same capable of supplying light quantity large enough to observe a projected picture even in a bright room, still continuing projection without interruption even when a lamp is burnt out and further adjusting the color tone of the projected picture to the satisfactory one. SOLUTION: A 1st light source 1 emitting parallel light rays, a 1st lens array 2 converging the parallel light rays to be plural beams, and a mirror 3 equipped with a transmission part 3a transmitting the beams from the 1st lens array 2 and a reflection part 3b reflecting the beams are arranged on the same optical path. A 2nd light source 4 emitting parallel light rays and a 2nd lens array 5 converging the parallel light rays to be plural beams are arranged so that the plural beams converged by the 2nd lens array 5 may be reflected by the reflection part 3b of the mirror 3 and the optical axis of the 2nd lens array 5 may form the same angle as the optical axis of the 1st lens array 2 to the normal of the mirror 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source for illumination and a liquid crystal projector using the same.

[0002]

2. Description of the Related Art In recent years, presentations by enlarging and projecting electronic images via a computer or the like with a liquid crystal projector have been increasing. Generally, a liquid crystal projector includes a light source for illumination, an optical system for splitting illumination light,
The liquid crystal panel includes a liquid crystal panel that transmits the divided light, a combining unit that combines light transmitted through the liquid crystal panel, and a projection optical system that enlarges and projects the combined light.

FIG. 7 is a schematic configuration diagram showing a conventional example of a liquid crystal projector. In this conventional example, the liquid crystal projector includes dichroic mirrors 12a, 12c and reflection mirrors 12b, 12c that reflect light emitted from the illumination light source 11 to reflect light of a predetermined wavelength and pass light of other wavelengths.
The light is divided into light of three primary colors, R, G, and B, through d and 12e, and guided to condenser lenses 13a, 13b, and 13c.
b, 13c, and are condensed to enter the liquid crystal panels 14a, 14b, 14c adapted to the three primary color lights, and the light emitted by each liquid crystal panel is reflected by only the corresponding color light. Incident on a cross prism 15 configured by combining four triangular prisms each having a reflecting surface that transmits light other than the three primary colors, emit light in one direction, and enter the projection lens 16 in one direction. The light emitted from the projection lens is projected on a screen (not shown) so that an image can be observed.

In general, an illumination light source 11 used in a liquid crystal projector has a lamp 1a as shown in FIG.
And a parabolic reflector 1b (or a concave lens 1c in addition to these, as shown in FIG. 9), and outputs the light from the lamp 1a to the parabolic reflector. 1
b (in the case of FIG. 9, the direction of the light reflected in the convergence direction by the parabolic reflector 1 b is refracted by the concave lens 1 c) so as to be emitted as parallel rays. As the lamp 1a, a discharge lamp such as an ultra-high pressure mercury lamp or a metal halide lamp is used. Among them, the ultra-high pressure mercury lamp is widely used because of its high luminous efficiency and utilization efficiency.

[0005]

Since the presentation is performed in a bright room, there is a demand for a bright liquid crystal projector which can be observed even in a bright room. However, in the conventional liquid crystal projector, the illumination light source is configured on the assumption that the projector is used in a dark room. Therefore, when used in a bright room, the projected image becomes relatively dark, and a clear projected image cannot be obtained. . Further, even if the power of the lamp itself used as the illumination light source is increased to make the illumination light even brighter, an ultra-high pressure mercury lamp cannot be manufactured with high power.

There is also a need for a liquid crystal projector that does not interrupt video even if the lamp goes out during a presentation. However, with conventional LCD projectors,
If the lamp burns out, the image cannot be projected without replacing it with a new lamp, and because the lamp is hot and hot, it cannot be used until the lamp cools down, and the presentation is interrupted. Was gone.

Further, the ultra-high pressure mercury lamp has a problem that a red color is hardly produced due to the emission spectrum of mercury.

Accordingly, the present invention can supply a sufficient amount of light for observing a projected image even in a bright room, and can continue projection without interruption even when a lamp is cut off, and furthermore, the color tone of the projected image is preferable. It is an object of the present invention to provide an illumination light source that can be adjusted to a color tone and a liquid crystal projector using the same.

[0009]

An illumination light source according to the present invention comprises a first light source that emits a parallel light beam, and a plurality of minute lenses that converge the parallel light beam from the first light source into a plurality of light beams. A combined first lens array, a plurality of transmitting portions that respectively transmit a plurality of light beams converged by the first lens array, and a plurality of reflections respectively reflecting a plurality of light beams on a back side of a portion other than the transmitting portion. A second light source emitting parallel light rays, and a plurality of microlenses for converging the parallel light rays from the second light source into a plurality of light fluxes. A plurality of light beams converged by the second lens array are reflected by each of the reflecting portions of the mirror, and the optical axis of the second lens array is adjusted by the method of the mirror. Before the line Characterized by being arranged so as to have the same angle with the optical axis of the first lens array.

The illumination light source according to the present invention is preferably such that, after separating a linearly polarized light component of the light beam into a P wave and an S wave on the optical path of the synthesized light beam, either one of the linearly polarized light beams PS polarization splitting / combining means for modulating the component in the same polarization direction as the other linearly polarized light component and combining the components is provided.

Further, the liquid crystal projector according to the present invention comprises an illumination light source, an optical system for dividing the illumination light, a liquid crystal panel transmitting the divided light, and synthesizing means for synthesizing the light transmitted through the liquid crystal panel. In a liquid crystal projector comprising a projection optical system for enlarging and projecting the combined light, the above-mentioned illumination light source is used as an illumination light source.

In the liquid crystal projector according to the present invention, preferably, lamps having different emission spectra are used as the first light source and the second light source.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of an illumination light source according to the present invention, FIG. 2 shows a lens array used in the illumination light source of the present embodiment, (a) is a front view, and (b)
3 is a plan view of (a), (c) is a right side view of (a), and FIG. 3 is a schematic configuration diagram showing one embodiment of a liquid crystal projector according to the present invention using the illumination light source of the present embodiment. As shown in FIG. 1, the illumination light source 11 of the present embodiment includes a first light source 1.
, The first lens array 2 and the mirror 3 are arranged on the same optical path, and the second light source 4 and the second lens array 5 are separated by the first light source 1 and the second They are arranged on the same optical path different from the optical path of one lens array 2.

The first light source 1 is composed of a lamp 1a and a parabolic reflector 1b, like the light source 1 shown in FIG. As the lamp 1a, a high-pressure discharge lamp such as a mercury lamp or a metal halide lamp is used. Parabolic reflector 1b
Is formed in a parabolic shape such that the reflection surface reflects the light emitted from the lamp 1a and the directions of the light beams become parallel. As shown in FIG. 2, the first lens array 2 is configured by arranging a plurality of small-diameter condenser lenses 2a on the same plane vertically and horizontally, and each of the condenser lenses 2a The parallel light beams emitted from the light source 1 are converged into a plurality of light beams. Note that the first light source 1 may have any configuration as long as the light emitted from the lamp 1a can be emitted in one direction by converting the light into parallel rays. For example, as shown in FIG. 9, a concave lens 1c is combined. Anything can be applied.

The mirror 3 has a plurality of reflective films for reflecting light on one surface (in FIG. 1, the second lens array 5 side) of a transparent plate made of a material having high light transmission such as glass. Are affixed in a slit shape (or are vapor-deposited), so that a plurality of transmission portions 3a transmitting incident light and a plurality of reflection portions 3b reflecting incident light are provided. The plurality of transmissive portions 3a and the plurality of reflective portions 3b have widths and arrangements adapted to the plurality of light beams converged by the first lens array 2 and the plurality of light beams converged by the second lens array 5, respectively. It is arranged with. And the first light source 1, the first
The lens array 2 and the mirror 3 are arranged on the same optical path with their positions adjusted so that the respective light beams converged by the first lens array 2 pass through the respective transmission portions 3a of the mirror 3. .

The second light source 4 is, like the first light source 1,
It is composed of a lamp 1a and a parabolic reflector 1b. Similarly to the first lens array 2, the second lens array 5 is configured by arranging a plurality of small-diameter condensing lenses 5a on the same plane.
Are converged into a plurality of light beams.

In the second light source 4 and the second lens array 5, the respective light beams converged by the second lens array 5 are reflected by the respective reflecting portions 3 b of the mirror 3, and The angle θ1 of the optical axis (of each condenser lens 2a) of the first lens array 2 with respect to the normal, and the second
Are arranged on an optical path where the angle θ2 of the optical axis (of each condensing lens 2a) of the lens array 5 is the same.

The liquid crystal projector shown in FIG. 3 is configured by replacing the illumination light source 11 of the present embodiment configured as described above with the conventional illumination light source 11 shown in FIG. . In FIG. 3, unlike the one shown in FIG. 7, lenses 17a, 17b, and 17c are inserted at predetermined positions between the illumination light source 11 and the condenser lenses 13a, 13b, and 13c.
The light beams converged by the lens array 1 and the second lens array 5 are dichroic mirrors 12a and 12c,
After an image of the light source is formed in the middle of the optical path passing through the reflecting mirrors 12b, 12d, and 12e, the light source is adjusted so that it does not diffuse more than the diameter of the condenser lens.

Since the illumination light source and the liquid crystal projector according to the present embodiment are configured as described above, the parallel light from the first light source 1 is converged by the first lens array 2 to form a plurality of light beams. The light passes through the transmitting portion 3a of the mirror 3. On the other hand, the parallel light from the second light source 4 is reflected by the reflecting portion 3b of the mirror 3 in a state where the parallel light is converged by the second lens array 5 to form a plurality of light beams.

At this time, the angle of the optical axis (of each condenser lens 2a) of the first lens array 2 with respect to the normal line of the mirror 3 and the light (of each condenser lens 2a) of the second lens array 5 Because the angle of the axis is the same, the first
The direction of the optical axis of the transmitted light beam transmitted from the light source 1 via the first lens array 2 and the transmission part 3 of the mirror 3 and the reflection part 3 of the mirror 3 from the second light source 4 via the second lens array 5
The direction of the optical axis of the reflected light beam reflected by is the same, and the light beams are combined.

After that, the combined light passes through the lens 17a,
Dichroic mirrors 12a, 12c, reflection mirror 12
b, lens 17b, reflection mirror 12d, lens 17c,
After being divided into light of three primary colors of R, G and B via a reflection mirror 12e and guided to condenser lenses 13a, 13b and 13c, a liquid crystal panel 14 adapted to each color light of the three primary colors.
Lights of the three primary colors are combined via a, 14b, 14c and a cross prism 15, emitted in one direction, incident on a projection lens 16, and projected as an image on a screen (not shown) via the projection lens 16.

Therefore, according to the illumination light source and the liquid crystal projector of this embodiment, the illumination light from the two light sources can be combined to almost double the amount of light without losing the amount of light. By using the same lamp, it is possible to supply the liquid crystal projector with an amount of light capable of observing the projected image in a bright room.

Also, even if the lamp of one of the two light sources is cut off while using the liquid crystal projector, the illumination light from the lamp of the other light source is emitted, so that the lamp does not need to be replaced. The image can be continuously projected.

Further, since light from two separate light sources is synthesized, a lamp having high luminous efficiency and utilization efficiency such as an ultra-high pressure mercury lamp is used as a lamp of one light source, and a lamp of the other light source is used as a lamp of the other light source. In the mercury emission spectrum, if the two light source lamps complement each other with different emission spectra, such as using a lamp with a weak red emission spectrum characteristic in the emission spectrum of mercury, the color tone of the projected image can be adjusted, Can be improved.

By the way, since polarized light is used for the liquid crystal panel, the liquid crystal panel 14 shown in FIG. 1 and FIG.
The light is polarized into one linearly polarized light component using a polarizing means before reaching a, 14b, and 14c (omitted in FIGS. 1 and 7). In this case, if only one of the two different linearly polarized light components is transmitted through the polarizing plate and made incident on the liquid crystal panel, the amount of light is reduced by half.

If one of the two different linearly polarized light components is modulated into the other linearly polarized light component, a bright projected image can be supplied without losing the light amount. In this case, the number of components increases, and the configuration of the entire liquid crystal projector becomes complicated. Further, the characteristics of the dichroic mirror are largely different between the S wave and the P wave, and cause a light amount loss. Therefore,
An embodiment capable of solving such a problem will be described below.

FIG. 4 is a schematic structural view showing another embodiment of the illumination light source according to the present invention, and FIG. 5 is a PS used in this embodiment.
FIG. 6 is a schematic diagram showing another embodiment of the liquid crystal projector according to the present invention using the illumination light source according to the present embodiment. As shown in FIG. 4, the illumination light source according to the present embodiment has a PS polarization splitter / synthesizer 6 arranged on the optical path synthesized via the mirror 3 in addition to the configuration of the illumination light source according to the embodiment in FIG. It is configured.

As shown in FIG. 5, the PS polarization splitting / synthesizing unit 6 includes a pair of minute polarizing films 6a and 6b formed in a transparent thin plate-like member by a first lens array 1 and a second lens array. A plurality of sets are provided in accordance with the number of light beams synthesized by the lens array 5, and the linearly polarized light component is rotated by 90 degrees to the exit position of the polarized light component reflected by the two polarizing films 6a and 6b, and the polarizing film 6a is rotated.
And a polarization component modulating means such as a λ / 2 plate 6c for matching the polarization component transmitted by the light source.

The two polarizing films 6a and 6b have the same polarization characteristics, and transmit the same linearly polarized light component of one of the P and S linearly polarized light components of the incident light beam.
The other is reflected. Here, for convenience of explanation, it is assumed that a P wave is transmitted and an S wave is reflected.
In addition, the PS polarization splitting / synthesizing unit 6 causes each light beam synthesized by the mirror 3 to pass between the two polarizing films 6a and 6b from the incident side of the PS polarization splitting / synthesizing unit 6 and to the first polarizing film 6a. The arrangement is adjusted to be incident.

According to the configuration of the present embodiment, the P wave transmitted through the first polarizing film 6a is used as it is by the PS polarization splitting / combining device 6.
The light from the lamps 1 and 4 is formed on a predetermined image forming plane. Further, the S wave reflected by the first polarizing film 6a is
And reflected by the second polarizing film 6b toward the polarizing film 6b.
After exiting from the polarization splitter / synthesizer 6, the λ / 2 plate 6
The polarization direction is rotated by 90 degrees by c and is modulated into a P wave,
The images of the lamps 1 and 4 are formed on a predetermined image plane. Thus, light from the two light sources is combined as light of the same linear polarization component.

The liquid crystal projector shown in FIG. 6 is configured by replacing the illumination light source 11 of the present embodiment thus configured in place of the illumination light source 11 of the embodiment shown in FIG. is there. FIG.
In the same manner as in the embodiment of FIG.
The lenses 17a, 17b, and 17c are inserted at predetermined positions between the condenser lenses 13a, 13b, and 13c from the first lens array 1 and the second lens array 5, respectively.
Is converged by the dichroic mirror 12
After the light source image is formed in the middle of the optical path passing through the reflection mirrors 12a, 12c, 12c, and 12e, the light source is adjusted so as not to diffuse more than the diameter of the condenser lens.

According to the illumination light source and the liquid crystal projector of the present embodiment configured as described above, in addition to the effects of the embodiments of FIGS. 1 and 3, the light source from the first light source 1 and the second light source 4 Since all the linearly polarized light components constituting the light are converted into the same linearly polarized light component and used for the liquid crystal panel, a bright projection image can be supplied without wasting light. In addition, since the light of the same linear polarization component is used inside the illumination light source, there is no need to provide a polarizing means on the optical path of each color light from the dichroic mirror to the liquid crystal plate, and the configuration can be simplified accordingly. it can.

In addition, the mirror 3 used for the illumination light source of the present invention comprises a first lens array 2 and a second lens array 5.
The configuration is not limited to the configuration of each of the above-described embodiments as long as the transmissive portion 3a and the reflective portion 3b are provided at a position where the light flux does not interfere. For example, the transmissive portion 3a may be formed as a slit.

The arrangement of the small diameter condenser lenses 2a and 5a of the first lens array 2 and the second lens array 5 is not limited to the arrangement of the above embodiment. Also,
Correspondingly, the transmitting portion 3a and the reflecting portion 3b of the mirror 3, and further, the polarizing films 6a and 6b of the PS polarization splitting / combining device are not limited as long as they can transmit or reflect the respective light beams as in the above embodiment. It may be configured in such a shape and arrangement.

The liquid crystal projector using the illumination light source of the present invention is not limited to the cross prism type liquid crystal projector as in each of the above embodiments, but may be applied to other types of liquid crystal projectors. It can be configured by combining the light sources for use.

Further, the illumination light source of the present invention can be widely applied to devices requiring illumination means other than the liquid crystal projector.

[0037]

As described above, according to the present invention, it is possible to supply a sufficient amount of light for observing a projected image even in a bright room, to continue projecting even when the lamp is cut off, and to further improve the color tone of the projected image. You can adjust the color tone.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an illumination light source according to the present invention.

FIGS. 2A and 2B show a lens array used for the illumination light source of the present embodiment, wherein FIG. 2A is a front view, FIG. 2B is a plan view of FIG.
It is a right view of (a).

FIG. 3 is a schematic configuration diagram showing one embodiment of a liquid crystal projector according to the present invention using the illumination light source of the present embodiment.

FIG. 4 is a schematic configuration diagram showing another embodiment of the illumination light source according to the present invention.

FIG. 5 is a diagram illustrating the principle of a PS polarization synthesizer used in the present embodiment.

FIG. 6 is a schematic configuration diagram showing another embodiment of the liquid crystal projector according to the present invention using the illumination light source of the present embodiment.

FIG. 7 is a schematic configuration diagram showing a conventional example of a liquid crystal projector.

FIG. 8 is a schematic configuration diagram showing a conventional example of an illumination light source.

FIG. 9 is a schematic configuration diagram showing another conventional example of a light source for illumination.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first light source 1a lamp 1b parabolic reflector 1c concave lens 2,5 first lens array 2a, 5a condenser lens with small diameter 3 mirror 3a transmitting part 3b reflecting part (reflection film) 4 second light source 6 PS polarization splitter / synthesizer 6a, 6b Polarizing film 6c λ / 2 plate 11 Light source for illumination 12a, 12b Dichroic mirror 13a, 13b, 13c Condenser lens 14a, 14b, 14c Liquid crystal panel 15 Cross prism 16 Projection lens

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 EA14 HA13 HA18 HA21 HA23 HA24 HA25 HA28 MA01 MA05 2H091 FA05Z FA08X FA08Z FA14Z FA21X FA26X FA26Z FA29Z FA41Z LA15 LA16 MA07 2H099 AA12 BA09 BA17 CA01 CA11 DA09

Claims (4)

[Claims] A first light source that emits a parallel light beam;
A first lens array in which a plurality of microlenses are combined to converge parallel light rays from the light source into a plurality of light beams, and a plurality of transmitting portions each transmitting the plurality of light beams converged by the first lens array A mirror having a plurality of reflecting portions for reflecting a plurality of light fluxes on the back side of a portion other than the transmitting portion, respectively, on a same optical path, and a second light source emitting a parallel light beam; A second lens array in which a plurality of microlenses are combined to converge parallel light rays from the light source into a plurality of light beams, and a plurality of light beams converged by the second lens array are reflected by the respective mirrors. A light source for illumination, the light source being reflected by a portion and arranged so that an optical axis of the second lens array is at the same angle as an optical axis of the first lens array with respect to a normal line of the mirror. 2. After separating a linearly polarized light component of the light beam into a P wave and an S wave on the optical path of the synthesized light beam, one of the linearly polarized light components is polarized in the same polarization direction as the other linearly polarized light component. 2. The illumination light source according to claim 1, further comprising a PS polarization division / synthesis unit for modulating and synthesizing the light. 3. An illumination light source, an optical system for splitting illumination light, a liquid crystal panel transmitting the split light, synthesizing means for synthesizing the light transmitted through the liquid crystal panel, and enlarging and projecting the synthesized light. 3. A liquid crystal projector comprising: a projection optical system, wherein the illumination light source according to claim 1 is used as an illumination light source. 4. The first light source and the second light source,
The liquid crystal projector according to claim 3, wherein lamps having different emission spectra are used.