JPH116980A - Projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a low-input lamp as a light source to prolong the life of the device and to continue projection in a somewhat dark state even when one lamp is burnt out because plural light sources are prepared by providing the light source with one concave reflection mirror per each and inclining the optical axis of the light source to an irradiated surface by a specified angle to the normal of the irradiated surface. SOLUTION: The light source is a metal halide lamp and is positioned on an axial center in the concave reflection mirror 2, and 1st and 2nd lens array bodies 3 and 5 and a condensing lens 100 are arranged on the irradiated surface 6 side. The mirror 2 is a parabolic mirror surface and reflects the light as parallel beams from the light source 1. Both light sources 1 and 1 are arranged so that their optical axes are symmetrically inclined by 2 deg. to 8 deg. to the normal (n) of the surface 6 and crossed at one point on the surface 6 so as to irradiate a common range on the surface 6. The surface 6 is a liquid crystal panel and the light passing through the liquid crystal panel passes through a projection lens in front of the liquid crystal panel and is projected to a screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projection device for projecting an image displayed on a liquid crystal panel or the like onto a screen.

[0002]

2. Description of the Related Art Conventionally, as a device for displaying a large screen image, a device such as a liquid crystal projector that illuminates an image displayed on a liquid crystal panel with strong light and projects the image on a screen is known. Projection devices are known. As a light source of this type of projection device, a 250 to 400 W lamp, which is relatively inexpensive to increase the input of the light source, is widely used. However, a lamp with a large input generally has a short service life, and the arc length cannot be shortened in relation to the service life, so that the light-collecting efficiency is poor. There is a big problem. Regarding the light use efficiency, the use efficiency of a liquid crystal projector using a current mainstream 250 W lamp is only about 2.5% lumen / W (2.0 ANSI Lumens / W). Further, if the lamp is cut off during the projection, the projection must be interrupted to replace the lamp. The present invention clarifies a projection device that can solve the above problem by using a plurality of lamps.

[0003]

A projection apparatus according to the present invention is a projection apparatus for combining light from a plurality of light sources (1) and projecting the combined light on an irradiation surface (6), wherein each light source (1) has one light source. It has one concave reflector (2) for (1), and each light source (1) for the irradiation surface (7)
Is inclined by 2 to 8 ° with respect to the normal line n of the irradiation surface (6).

[0004]

[Operation and Effect] Since a plurality of light sources (1) are used, a lamp having a small input can be used as the light source. Generally, a lamp with a small input has a longer life than a lamp with a large input, so that the frequency of replacement for one lamp is reduced.
Further, by using a plurality of lamps, even if one lamp is cut off, the projection can be continued although the image is slightly darkened,
The inconvenience of interrupting the projection is eliminated. Further, a lamp with a small input can shorten the arc length, thereby improving the light collection efficiency. Further, since a lamp with a small input generates a small amount of heat, a small cooling fan is required and the operating noise can be reduced.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (FIG. 1) FIG. 1 shows an embodiment in a Koehler illumination optical system.
The light source of the embodiment is a metal halide lamp, which is located on the axis of the concave reflecting mirror (2) and on the axis of the concave reflecting mirror (2), and is provided with a condenser lens ( 100) are deployed. The concave reflecting mirror (2) is a parabolic mirror, and reflects light from the light source (1) as parallel light. The optical axes of both light sources (1) are symmetrically inclined at an angle of 2 to 8 ° with respect to the normal line n of the irradiation surface (6), intersect at one point on the irradiation surface (6), and are common on the irradiation surface (6). It is arranged to irradiate a range. The irradiation surface (6) is a liquid crystal panel, and the light passing through the panel is projected on a screen (neither is shown) through a projection lens in front of the panel.

In FIG. 1, an irradiation surface (6) is shown for easy understanding.
Since the inclination of the optical axis of the light source (1) is drawn larger than the actual line with respect to the normal line n, the concave reflecting mirrors (2) and (2) are apart from each other. 2) interfere with each other. For this reason, as shown in FIG. 6, an abutting edge (21) of the adjacent concave reflecting mirrors (2) and (2) with each other's concave reflecting mirror (2) is assumed to pass through the middle between two adjacent optical axes. It is cut in a plane, and the curved cut end faces are in contact with each other. After the concave reflecting mirror (2) is manufactured into a uniform shape, the interference portion may be cut off or may be formed from the beginning into the final shape shown in FIGS. 6 (a) and 6 (b). 2
The reason why the optical axes of the two light sources (1) and (2) are inclined by 2 to 8 ° with respect to the normal line n of the irradiation surface (6) is that if the angle is less than 2 °, the concave reflecting mirror
(2) (2) If the interference between them is too large, that is, 8 ° or more, the amount of light falling off the projection lens in front of the panel increases, and the light collection rate deteriorates.

Second Embodiment (FIG. 2) The following second to eighth embodiments are embodiments in an integrator illumination optical system having a small difference in brightness between the central portion and the peripheral portion of the irradiation surface (6). . As shown in FIG. 2, the optical axes of the two light sources (1) and (1) intersect at one point on the irradiation surface (6), which is a liquid crystal panel, as in FIG. n is symmetrically inclined with respect to n by 2 to 8 ° for the same reason as described above. Each light source (1) is provided with concave reflecting mirrors (2) and (2), which are parabolic mirrors, as in the first embodiment. Between the light source (1) and the irradiation surface (6), first and second lens array bodies (3) and (5) and a condenser lens (100) are provided in order from the light source (1). You. The two lens array bodies (3) and (5) are formed of a transparent glass or a transparent resin, and as shown in FIG. Are arranged in a plane orthogonal to the optical axis.

The two lens array units (3) and (5) are arranged so that the optical axis passes through the center of the lens array unit where the vertical and horizontal center lines intersect, and the first lens array unit (3) and the second lens array unit
The interval of (5) is such that the luminous flux incident on the convex lens (31) of the first lens array body (3) on the light source (1) side is equal to the second lens array body.
It is set to converge by the convex lens (51) of (5).
As is well known, each convex lens (3) of the first lens array body (3) is
The light emitted from 1) is incident only on the facing convex lens (51) of the convex lens group of the second lens array body (5),
Irradiation surface from each convex lens (51) of lens array body (5)
(6) The above common area is irradiated.

Third Embodiment (FIG. 4) FIG . 4 shows an embodiment in which an elliptical reflecting mirror is used as the concave reflecting mirror (2). The optical axes of the two light sources (1) and (1) intersect at one point on the irradiation surface (6), which is a liquid crystal panel, as in FIG.
Are symmetrically inclined with respect to the normal line n by 2 to 8 ° for the same reason as described above. Each light source (1) is provided with concave reflecting mirrors (2) and (2), which are elliptical mirrors, as in the first embodiment. Between the light source (1) and the irradiation surface (6), first and second lens array bodies (3) and (5) are provided in order from the light source (1).

The two lens array bodies (3) and (5) are formed by arranging 25 convex lenses (31) and (51) in a plane perpendicular to the optical axis in the same manner as described above. The reflected light from the concave reflecting mirror (2), which is a plane mirror, is not a parallel light but a convergent light, and therefore, compared to the first lens array body (3) on the light source (1) side.
The second lens array body (5) is formed small, and the condenser lens (100) required in the second embodiment is not required.
The distance between the first lens array body (3) and the second lens array body (5) is such that the light beam incident on the convex lens (31) of the first lens array body (3) on the light source (1) side is the second lens. It is set so as to converge on the convex lens (51) of the array body (5).

Fourth Embodiment (FIGS. 8 and 9) In the second and third embodiments, the second lens array
A polarization conversion element plate (7) is provided on the exit side of (5). The polarization conversion element plate (7) comprises a PBS (4), which is a prism composite having a polarization separation film (40) inside, and a reflection film inside.
A pair consisting of a mirror body (8) which is a prism composite having (80) is used as a basic structural unit, and a plurality of pairs are opposed to the second lens array body (5). Each convex lens (51) constituting the second lens array body (5) is opposed to a pair of basic structural units of the polarization conversion element plate (7). A λ / 2 wavelength plate (82) is provided on the front surface of each mirror body (8), and a partial light shielding plate (81) is provided on the rear surface of each PBS (4).

The light from the light source (1) is condensed by the first and second lens array bodies (3) and (5), and then the partial light shielding plate (81)
And enters only the PBS (4) of the polarization conversion element plate (7). The light incident on the PBS (4) is allowed to pass only the P wave, and the S wave is reflected. S wave is a reflection film of mirror body (8)
(80), is incident on the λ / 2 wavelength plate (82),
The plane of polarization is rotated by the two-wavelength plate (82) and converted into a P-wave. In this way, all the light passing through the polarization conversion element plate (7) is converted into a P wave. or. If a λ / 2 wave plate (82) is used for the P wave passing through the PBS (4), all the light is converted to the S wave. On the irradiation surface (6) of the liquid crystal panel, only the polarized light that is opposed to the alignment direction of the liquid crystal molecules passes through the irradiation surface (6).
Since the light passes through (6), the light collection efficiency can be greatly increased.

Fifth Embodiment (FIG. 10) In the second and third embodiments, the second lens array
The polarization conversion element plate (7) is provided on the incident side of (5). Since the configuration and operation of the polarization conversion element plate (7) are the same as those of the fourth embodiment, the same reference numerals as in the fourth embodiment denote the same parts, and a description thereof will be omitted. In the case of FIG. 10, the second lens array body
Since (5) is located on the exit side of the polarization conversion element plate (7), the indeterminate polarized light from the light source (1) is transmitted to the first lens array body.
The light passes only through (3) and reaches the polarization conversion element plate (7). Therefore, the amount of refraction of the irregularly polarized light is small, and the P-wave and the S-wave, which are polarized light, accurately follow the optical path in the polarization conversion element plate (7). As a result, the projection means can uniformly irradiate the irradiation range of the irradiation surface (6).

A λ / 2 wavelength plate (82) serving as an auxiliary polarizing means.
Is located between the second lens array body (5) and the polarization conversion element plate (7), the λ / 2 wavelength plate (82) is attached to the flat surface on the incident side of the second lens array body (5). Can be attached. Generally, the second lens array body is compared with the polarization conversion element plate (7).
(5) is inexpensive, and even if the λ / 2 wavelength plate (82) is attached to the wrong position on the second lens array body (5), the loss for replacement is reduced.

Sixth Embodiment (FIG. 11) In the embodiment of FIG. 2, the light of one light source (1) is applied to the irradiation surface (6) via a total reflection mirror (64). The optical axes of the two light sources (1) and (1) intersecting at one point on the irradiation surface (6) are
They are symmetrically inclined by 2 to 8 ° with respect to the normal line n of the irradiation surface (6). In the case of the embodiment shown in FIG. 11, bright light near the center of the light source (1) can be irradiated by using an efficient large circular reflecting mirror. In addition, the concave reflector (2) of the two light sources (1) and (1)
Since the interference of (2) can be avoided, it is not necessary to make the concave reflecting mirror (2) a special shape as shown in FIGS. 6 (a) and 6 (b).

Seventh Embodiment (FIG. 12) This is a projection apparatus incorporating three total reflection mirrors (63) (64) (65) and three dichroic mirrors (903) (904) (905).
A screen (not shown) is provided in front of the apparatus main body (900), and a projection lens (902) including a lens group is provided at a front end of the apparatus main body (900) so as to face the screen. . At the rear end of the apparatus main body (900), two light sources (1) and (1) are provided as in the second embodiment. light source
(1) On the optical path from (1) to the projection lens (902), there are three dichroic mirrors (903) (904) (904) (905), R, G, and B inclined at 45 ° to the optical path. Three liquid crystal panels (60) (61) (62) corresponding to three primary colors and three total reflection mirrors
(63), (64) and (65) are deployed as known. A concave reflecting mirror (2) corresponding to two light sources (1), a first lens array (3), a second lens array (5) on each optical axis, and a condenser lens
(100) is provided, and the angle formed by the optical axis is 4 to 16 °. This is because the angle between the two optical axes in the first, second and third embodiments is 4 to 16 ° (the light of the two light sources (1) and (2) with respect to the normal line n of the irradiation surface (6)). (Because the angle between the axes is 2 to 8 °).

Only the red light passes through the dichroic mirror (903), and the passed light is reflected by the total reflection mirror (64).
The liquid crystal panel for red light (60) is irradiated. On the other hand, the light beam reflected by the dichroic mirror (903) reflects green light by the dichroic mirror (904), and the reflected light illuminates the liquid crystal panel (61) for green light. The light beam that has passed through the dichroic mirror (904) is reflected by the dichroic mirror (905) and the total reflection mirror (65), and then irradiates the liquid crystal panel (62) for blue light. For red light,
The luminous flux that has passed through the liquid crystal panels for green light and blue light (60), (61), and (62) enters the color synthesis prism (901), where the red, blue, and green lights are emitted. An image corresponding to each light is synthesized, and is projected on a screen (not shown) by the projection lens (902).

Eighth Embodiment (FIG. 13) Projection incorporating four dichroic mirrors (903) (904) (905) (906) and three total reflection mirrors (63) (64) (65) Device. On the optical path from the light sources (1) and (1) to the projection lens (), four dichroic mirrors (903) (904) (905) (906) inclined at 45 ° with respect to the optical path and R, Three display panels (60) (61) (62) corresponding to the three primary colors G and B, and three total reflection mirrors (63) (64) (65) are provided in a known manner.
A concave reflecting mirror (2) corresponding to the two light sources (1), a first lens array body (3), a second lens array body (5), and a condenser lens (100) are provided on each optical axis, The angle between the optical axes is 4-16
゜.

Only the red light passes through the dichroic mirror (903) and the red light display panel (6) passes through the total reflection mirror (64).
0) is irradiated. On the other hand, the light beam reflected by the dichroic mirror (903) has green light reflected by the dichroic mirror (904), and the reflected light is a display panel (61) for green light.
Is irradiated. The light beam passing through the dichroic mirror (904) irradiates the display panel (62) for blue light,
The light is reflected by the total reflection mirror (65) and reaches the dichroic mirror (906). Display panel for red light and green light
The luminous flux passing through (60) and (61) is converted to a dichroic mirror (90
The light is synthesized by 5) and enters the dichroic mirror (906). Images corresponding to red, blue, and green lights are synthesized by a dichroic mirror (906), and are projected onto a screen by a projection lens (902).

Ninth Embodiment (FIG. 5) In the first to eighth embodiments, two light sources (1) are used.
This is an embodiment in which (1) is linked to a lamp control unit (300) capable of switching on both light sources (1) and (1) simultaneously or arbitrarily and lighting only one lamp. As shown in FIG. 5, when the AC power outlet (301) and the main power supply circuit (302) are turned on, the lamp control circuit (303) and the timer (304) are energized. The lamp selection switch (305) includes a normal switch and an economy switch. When the normal switch is turned on, the lamp control circuit is driven, the relays (306) and (307) operate, and the lamp ballasts (308) and (309) are energized to light the two light sources (1) and (1). When the economy switch of the lamp selection switch (305) is turned on, the lamp control circuit (303) is driven, and the lighting time for each light source is integrated by the timer (304) of each light source (304). Alternatively, (307) operates to energize either of the lamp ballasts (308) or (309) to light the light source (1) with the shorter lighting integration time.

As described above, in the first to ninth embodiments, 2
Since one light source (1) is used, a lamp with a smaller input can be used as compared with the case of one light source. Generally, a lamp with a small input has a longer life than a lamp with a large input, so that the frequency of replacement for one lamp is reduced. Further, by using a plurality of lamps, even if one lamp is cut off, the projection can be continued although the image is slightly darkened, and the inconvenience of interruption of the projection is eliminated. Further, a lamp with a small input can shorten the arc length, thereby improving the light collection efficiency.

Recently, a liquid crystal projection device combining a short arc lamp of 100 W and a polarization conversion element plate has been commercialized and has a high efficiency of 6.5% lumen / W (6.5 ANs Lumens / W) and a high efficiency of 4%.
A long lamp life of 000 hours or more has been realized. By adopting the combination of the short arc lamp of 100 W and the polarization conversion element plate in the present invention, 1300 ANS
I (6.5% lumens / W, 6.5 ANSI Lumens / W) high brightness liquid crystal projector can be realized.

Other Embodiments In the first to ninth embodiments, the number of the light sources (1) is two. However, the present invention is not limited to this, and the number of the light sources (1) may be three or more. Can also. For example, when four light sources are used, two at the top and two at the bottom, the concave reflecting mirror (2) of each light source is
As shown in FIG. 7, if the abutting edges (21) and (21) of two adjacent concave reflecting mirrors (2) are cut so as to be 90 ° when viewed from the front of the concave reflecting mirror (2), interference will occur. Can be avoided.

The description of the above embodiments is for the purpose of illustrating the present invention and should not be construed as limiting the invention described in the appended claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment using Koehler illumination.

FIG. 2 is an explanatory diagram of an embodiment using a parabolic mirror and a condenser lens (100) in an integrator illumination optical system.

FIG. 3 is a perspective view of a lens array body.

FIG. 4 is a front view showing an irradiation area of the display panel.

FIG. 5 is a block diagram of a light source switching control circuit.

FIG. 6A is a front view of a concave reflecting mirror when two light sources are used, and FIG.
Is a cross-sectional view as viewed from the side.

FIG. 7A is a front view of a concave reflecting mirror when four light sources are used, and FIG.
Is a cross-sectional view as viewed from the side.

FIG. 8 is a sectional view in which a polarization conversion element plate is provided on the emission side of the second lens array body.

FIG. 9 is a perspective view of a polarization conversion element plate.

FIG. 10 is a cross-sectional view in which a polarization conversion element plate is provided on the incident side of the second lens array body.

FIG. 11 is an explanatory diagram in a case where one light source is reflected by a reflection mirror.

FIG. 12 is an explanatory diagram of a projection device using three total reflection mirrors and three dichroic mirrors.

FIG. 13 is an explanatory diagram of a projection device using three total reflection mirrors and four dichroic mirrors.

[Explanation of symbols]

 (1) Light source (2) Concave reflector (3) First lens array (5) Second lens array (6) Irradiation surface (7) Polarization conversion element plate

Claims (9)

[Claims] 1. An irradiation surface by combining lights of a plurality of light sources (1).
(6), wherein each light source (1) has one concave reflecting mirror (2) for one light source (1) and each light source (1) for an irradiation surface (6). The optical axis of) is the normal line n of the irradiation surface (6).
The projection device is inclined at 2 to 8 degrees with respect to the projection device. 2. A projection apparatus for projecting light from a pair of light sources (1) onto a screen via a plurality of total reflection mirrors, a plurality of dichroic mirrors, and a projection lens.
Is a projection device which has one concave reflecting mirror (2) for one light source (1), and an angle between optical axes of adjacent light sources is 4 to 16 °. 3. The concave reflecting mirror (2) is a parabolic reflecting mirror,
A first lens array body (3), a second lens array body (5), and a condenser lens (100) are arranged on the irradiation surface (6) side of each of the light sources (1) in order from the light source (1). The first lens array body (3) and the second lens array body (5) are arranged, and a plurality of convex lenses (31) and (51) are formed by being arranged along a plane orthogonal to the optical axis. Item 3. The projection device according to item 1 or 2. 4. The concave reflecting mirror (2) is an elliptical reflecting mirror,
A first lens array body (3) and a second lens array body (5) are provided on the irradiation surface (6) side of each light source (1) in order from the light source (1). The body (3) and the second lens array body (5) are formed by arranging a plurality of convex lenses (31) and (51) along a plane orthogonal to the optical axis.
Or the projection device according to 2. 5. An abutting edge of each of the adjacent concave reflecting mirrors (2) and the other concave reflecting mirror (2) is in a curved shape in an imaginary plane passing through the middle between two adjacent optical axes. The projection device according to claim 1, wherein the projection device is formed in the following manner. 6. The light source according to claim 1, wherein light from at least one of the plurality of light sources is bent by a total reflection mirror and incident on an irradiation surface. A projection device according to any of the above. 7. The projection device according to claim 1, wherein a polarization conversion element plate (7) is provided on one of the incident side and the exit side of the second lens array body (5). 8. Each light source (1) is linked to a control unit (300) having a switching function of turning on all light sources and turning on only one arbitrary light source (1). The projection device according to any one of claims 1 to 7. 9. The control section (300) has a lighting time integration function for each light source (1), and can automatically select and turn on a lamp having a short lighting integration time at the time of lighting. The projection device according to item 1.