JP3913682B2 - Projection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projection apparatus that displays an image on a screen.
[0002]
[Prior art]
FIG. 12 is a plan view showing the inside of a conventional projection apparatus (see, for example, Patent Document 1). A light source (1) is provided in the cabinet (2), and indefinite polarized light emitted from the light source (1) is reflected by the reflector (10) and travels straight. On the optical path from the light source (1), a lens array body (3) (30) configured by arranging a plurality of convex lenses vertically and horizontally, and the incident light is emitted with either P wave or S wave aligned. Polarizing beam splitter (8), dichroic mirror (60) (61) tilted with respect to the optical path, three liquid crystal panels (7) (7a) (7b) corresponding to the three primary colors R, G and B, and a total reflection mirror (62) (63) (64) (65) are provided. A color synthesizing prism (66) and a projection lens (6) are provided at the front end of the cabinet (2), and a screen (20) is provided in front of the cabinet (2) so as to face the projection lens (6). Has been.
[0003]
The dichroic mirror (60) on the light source (1) side allows only red light to pass through, and the passing light is reflected by the total reflection mirror (64) to irradiate the liquid crystal panel (7) for red light. On the other hand, of the light reflected by the dichroic mirror (60), green light is reflected by the dichroic mirror (61), and the reflected light irradiates the liquid crystal panel (7a) for green light. The blue light that has passed through the dichroic mirror (61) is reflected by the total reflection mirrors (62) and (65), and then irradiates the liquid crystal panel (7b) for blue light. Light that has passed through the liquid crystal panels (7), (7a), and (7b) for red light, green light, and blue light is incident on the color combining prism (66). An image corresponding to each light of red, blue and green is synthesized by the color synthesizing prism (66), and irradiated to the screen (20) by the projection lens (6).
[0004]
13 (a) and 13 (b) are exploded perspective views of the liquid crystal panel (7). FIG. 13 (a) shows a state where no electric field is applied to the liquid crystal panel (7), and FIG. Each state where an electric field is applied is shown. The liquid crystal panel (7) is configured by sealing liquid crystal molecules (72) in a small space formed between transparent display substrates (70) (71). Polarizing plates (73) and (74) that allow one of two orthogonally polarized lights to pass through are attached to the outside of each display substrate (70) and (71). The vibration planes of polarized light that allow passage are shifted from each other by 90 degrees.
When an electric field is not applied between the display substrates (70) and (71), as shown in FIG. 13 (a), the polarized light having passed through the incident-side polarizing plate (73) is 90 degrees due to the twist of the liquid crystal molecules (72). It passes through the polarizing plate (74) on the emission side while being bent. Accordingly, the corresponding color is displayed brightly on the liquid crystal panel (7).
When an electric field is applied between the display substrates (70) and (71), as shown in FIG. 13 (b), the liquid crystal molecules (57) are vertically aligned and polarized light that has passed through the polarizing plate (73) on the incident side. Passes through the gap between the liquid crystal molecules (72). Since the polarized light is blocked by the output-side polarizing plate (74), it is displayed in black on the liquid crystal panel (7). The liquid crystal panel (7) displays an image by switching the presence or absence of an electric field for each small space.
[0005]
When the image is not temporarily projected on the screen (20), an electric field is applied between the display substrates (70) and (71) of the liquid crystal panel (7) with the light source (1) turned on. The liquid crystal panels (7), (7a) and (7b) corresponding to the respective colors should appear black, and black should be displayed on the screen (20). Since the light source (1) is turned on, the next image can be projected quickly on the screen (20).
However, in recent years, the projection apparatus is required to have high brightness, and the light from the light source (1) is very bright. Accordingly, in the state where an electric field is applied between the display substrates (70) and (71) of the liquid crystal panel (7), light that should be blocked is leaked from the polarizing plates (73) and (74). As a result, black is not accurately displayed on the liquid crystal panel (7) and the screen (20), and the screen (20) is bright.
As a countermeasure, the applicant has conceived of applying the previously proposed configuration (see, for example, Patent Document 2). As shown in FIG. 14, a shutter mechanism (5) that covers the projection lens (6) is provided at the front end of the cabinet (2), and the shutter mechanism (5) includes two electric shutter plates (51). (51). When the image is not projected on the screen (20) temporarily, the shutter plates (51) (51) are closed. Nothing is illuminated on the screen (20) and it appears black.
[0006]
[Patent Document 1]
Japanese Patent No. 3291448 (Fig. 1)
[0007]
[Patent Document 2]
Japanese Patent No. 3272275 (Fig. 1)
[0008]
[Problems to be solved by the invention]
In the configuration shown in FIG. 14, light from the light source (1) is applied to the polarizing plates (73), (74) (see FIG. 13) of the liquid crystal panel (7) with the shutter plates (51) (51) closed. It is hit. As described above, since the light from the light source (1) is very bright, the polarizing plates (73) and (74) become hot.
However, the polarizing plates (73) and (74) are generally vulnerable to temperature rise, and if they continue to be irradiated with the light source (1), they may be overheated and damaged. In particular, since the light source (1) is continuously irradiated until no image is irradiated on the screen (20), there is a strong possibility that the polarizing plates (73) and (74) are damaged. The applicant has conceived that the shutter mechanism (5) is disposed closer to the light source (1) than the polarizing plates (73) and (74).
The shutter plate (51) is often made of metal in consideration of heat resistance, but when all of the light reflected by the shutter plate (51) reaches the light source (1), the light source (1) is overheated. There is a risk of damage.
An object of the present invention is to provide a projection device that does not overheat a polarizing plate when an image is not projected temporarily. Another object is to prevent the light source from being damaged by the light reflected by the shutter plate.
[0009]
[Means for Solving the Problems]
Means for solving the above problems include a pair of lens array bodies through which light emitted from a light source passes, a polarizing beam splitter that aligns light from the pair of lens array bodies to either P waves or S waves, In a projection apparatus that includes a liquid crystal panel that is irradiated with light from the polarization beam splitter and has a polarizing plate, the projection apparatus further includes a shutter mechanism that shields light from the light source, and the shutter mechanism includes a light shielding strip and a light shielding strip. The shutter plate is composed of a pair of shutter plates formed between them. One shutter plate is fixedly arranged on the incident side of the polarization beam splitter, and the other shutter plate has irregular reflection means for irregularly reflecting light from the light source. At the same time, a drive mechanism is provided between the pair of lens array bodies so that the light from the light source can be moved by moving the other shutter plate by the drive mechanism. Together are configured to be light, the plurality of fins are cooled by the fan, characterized in that it is configured to strike the light irregularly reflected by the diffuse reflection means of the other shutter plate.
[0010]
[Action and effect]
Since the shutter mechanism (5) is disposed between the dichroic mirror (60) on the light source (1) side and the light source (1), the dichroic mirror (60) when the shutter mechanism (5) is closed. The light from the light source (1) does not reach the liquid crystal panel (7) irradiated with the light from. Therefore, when the shutter mechanism (5) is closed, the polarizing plates (73) and (74) of the liquid crystal panel (7) are not overheated and damaged.
Further, since the shutter plate (51) is provided with irregular reflection means, the possibility that the light source (1) is damaged by the light reflected by the shutter plate (51) can be reduced.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
(overall structure)
Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view showing the inside of the projection apparatus. A light source (1) is provided at the rear end of the cabinet (2), and indefinite polarized light emitted from the light source (1) is reflected by the reflector (10) and travels straight. On the optical path from the light source (1), a cut filter (11) for removing ultraviolet rays and infrared rays, and a lens array body (3) (30) comprising a plurality of convex lenses (31) (31) arranged vertically and horizontally (Refer to FIG. 3), a polarizing beam splitter (8) for emitting incident light aligned with either P wave or S wave, dichroic mirrors (60) (61) tilted with respect to the optical path, R, G, B Three liquid crystal panels (7) (7a) (7b) and total reflection mirrors (62) (64) (65) corresponding to the three primary colors are provided. A shutter mechanism (5) is provided on the incident side of the polarization beam splitter (8).
A projection lens (6) is provided at the front end of the cabinet (2), and a screen (20) is disposed in front of the cabinet (2) so as to face the projection lens (6). The optical path from the dichroic mirror (60) (61) to the projection lens (6) is the same as the conventional one.
[0012]
In this example, a shutter mechanism (5) is provided between the dichroic mirror (60) on the light source (1) side and the light source (1), specifically on the incident side of the polarization beam splitter (8). Yes. When the image is not temporarily displayed on the screen (20), the shutter mechanism (5) is closed. First, the polarization beam splitter (8) will be described.
As is well known, the light from the light source (1) is indefinitely polarized light in which P wave and S wave are mixed, and the polarizing plates (73) and (74) of the liquid crystal panel (7) are either P wave or S wave. Permeate only one side. The polarization beam splitter (8) emits either P wave or S wave, here, S wave.
FIG. 2 is a plan view of the polarizing beam splitter (8). This includes a partially transmitting prism (80) that transmits P waves and reflects S waves laterally, and a mirror body (81) that reflects S waves reflected by the prisms (80) and emits them forward. Each pair is arranged vertically and horizontally perpendicular to the optical axis L. The light that has passed through the convex lens (31) of the lens array body (30) is only incident on the transmission prism (80) and not on the mirror body (81). On the exit surface of the partially transmitting prism (80), a λ / 2 wave plate (82) that polarizes P wave into S wave is provided, and only S wave is emitted from the λ / 2 wave plate (82). Is done. That is, the indefinite polarized light is aligned with the S wave and emitted by the polarization beam splitter (8). Only the P wave may be emitted from the polarization beam splitter (8).
[0013]
The shutter mechanism (5) shown in FIG. 1 is provided on a fixed shutter plate (50) disposed between the polarization beam splitter (8) and the lens array body (30), and on the exit side of the lens array body (30). And a movable shutter plate (51). Both shutter plates (50) and (51) are made of metal that reflects light, and are formed by opening a slit (53) between the light shielding strips (52) and (52) (see FIG. 3).
As a mechanism for moving the movable shutter plate (51), a motor (M) and a gear (55) connected to the motor (M) are provided above the movable shutter plate (51) as shown in FIG. A configuration in which a rack (54) formed on the upper end of the shutter plate (51) and a gear (55) are engaged is conceivable. Further, as shown in FIG. 4, the plunger (56) is connected to the movable shutter plate (51), and the shutter plate (51) can be moved along with the movement of the anvil (57) of the plunger (56). Conceivable. Further, instead of the motor (M), a hand turning knob (not shown) may be used.
[0014]
(Shutter opening / closing operation)
FIGS. 5A, 5B, and 5C are plan views showing the opening and closing operations of the movable shutter plates 51 and 51, with the shutter plates 51 and 51 being broken. As shown in FIG. 5 (a), the slit (53) of the fixed shutter plate (50) partially faces the transmission prism (80) and allows light to enter the prism (80). The light shielding strip (52) of the fixed shutter plate (50) faces the mirror body (81) and prevents unnecessary light from entering the mirror body (81).
When the image is not projected on the screen (20) temporarily, the movable shutter plate (51) is moved horizontally (upward in the figure) perpendicular to the optical axis with the light source (1) turned on. . The light shielding strip (52) partially faces the transmission prism (80). In FIG. 5 (b), the light shielding strip (52) covers a part of the transmission prism (80), and the amount of light incident on the transmission prism (80) is smaller than that shown in FIG. 5 (a). The state is about 50%.
Further, when the movable shutter plate (51) is moved and the light shielding strip (52) partially covers the transmission prism (80) as shown in FIG. 5 (c), the light from the light source (1) is moved to the movable shutter plate. Blocked by (51). Black is displayed on the screen (20).
[0015]
Since the movable shutter plate (51) is disposed between the dichroic mirror (60) on the light source (1) side and the light source (1), when the movable shutter plate (51) is closed, the dichroic mirror ( The light from the light source (1) does not reach the liquid crystal panel (7) irradiated with the light from 60). Therefore, when the movable shutter plate (51) is closed, the polarizing plates (73) and (74) provided on the liquid crystal panel (7) are not overheated and damaged.
Further, since each conventional shutter plate (51) shown in FIG. 14 needs to cover and expose the front half of the projection lens (6), the movement stroke of each shutter plate (51) is the same as that of the projection lens (6). More than half the width is required. Specifically, when the screen diagonal of the liquid crystal panel (7) is 1.8 inches, the moving stroke of each shutter plate (51) is about 30 mm. However, in this example, the movable shutter plates (51) and (51) may only partially cover the transmission prism (80), and the actual moving stroke is about 4 mm. Such a projection apparatus is also required to be miniaturized, and the projection apparatus can be miniaturized by shortening the moving stroke of the shutter plate (51).
The shutter mechanism (5) may be disposed between the polarization beam splitter (8) and the dichroic mirror (60) on the light source (1) side. However, since the movable shutter plate (51) needs to partially cover the transmission prism (80) and the mirror body (81), the moving stroke is larger than that shown in FIG.
[0016]
FIG. 6 is a plan view showing the shutter mechanism (5) in which two movable shutter plates (51) and (51) are stacked, and the movable shutter plates (51) and (51) are broken. The light shielding effect can be enhanced by stacking two movable shutter plates (51) and (51). Three or more movable shutter plates (51) (51) may be stacked.
FIG. 7 is a plan view of the movable shutter plate (51) in which the light shielding strip (52) is formed in a mountain-shaped cross section, and the tip of the light shielding strip (52) faces the light source (1). When the movable shutter plate (51) is closed, the light from the light source (1) is irregularly reflected upward or downward, and the light reaching the light source (1) is part of the reflected light. Or, the reflected light does not reach the light source (1) at all. Therefore, the possibility that the light source (1) is damaged by the light reflected by the shutter plate (51) can be reduced.
As shown in FIG. 8, the effect of irregularly reflecting the light from the light source (1) can be obtained even if the light shielding strip (52) is formed in a circular arc shape and the bulge is directed toward the light source (1).
[0017]
FIG. 9 is a cross-sectional plan view showing a projection apparatus that diffuses light from the light source (1) and is air-cooled by a fan (9). The movable shutter plate (51) is disposed in a cylindrical body (90) opened on both sides, and a fan (9) (9) (outside the movable shutter plate (51) at the side end of the cylindrical body (90)). 9) is provided. The fans (9) and (9) always rotate when the light source (1) is irradiated, and thereby the inside of the cylinder (90) is air-cooled.
Between the fan (9) and the movable shutter plate (51), an intermediate plate (91) having a large number of fins (92) and (92) and air passage holes (93 and 93) is provided.
The light shielding strip (52) of the movable shutter plate (51) is formed in a substantially triangular cross section with the tip portion facing the light source (1), and the light from the light source (1) is applied to the surface of the light shielding strip (52). A large number of small convex surfaces (94) and (94) of the circular arc strip to be irregularly reflected are formed (see FIG. 10). The lens array body (3) (30) is fitted on the peripheral surface of the cylindrical body (90).
When the movable shutter plate (51) is closed, the light shielding strip (52) diffuses and reflects light from the light source (1). The irregularly reflected light strikes the fins 92 and 92 of the intermediate plate 91 and heats the fins 92 and 92. The fins 92 and 92 are air-cooled by the fans 9 and 9, thereby preventing overheating between the polarizing beam splitter 8 and the light source 1.
[0018]
In the above description, the fans (9) and (9) are always rotating in the irradiation state of the light source (1). However, the motor (M) for moving the movable shutter plate (51) and the fan (9) are connected to the control circuit (95), and the fan (9) is rotated only when the movable shutter plate (51) is closed. May be. That is, when the movable shutter plate (51) is closed, the reflected beam from the light source (1) overheats between the polarizing beam splitter (8) and the light source (1), so the fan (9) must be rotated. . At this time, if the fan (9) is rotated only when the movable shutter plate (51) is closed, the power consumption of the fan (9) can be reduced.
[0019]
In the above description, three liquid crystal panels (7), (7a) and (7b) are provided corresponding to the three primary colors of light. However, as shown in FIG. 11, this type of projection apparatus displays an image on a single liquid crystal panel (7) and irradiates it with light passing through a polarizing beam splitter (8). There is a device. Such a device can also be provided with the shutter mechanism (5) of this example between the liquid crystal panel (7) and the light source (1).
[0020]
As a means for temporarily blocking light from the light source (1), a cap (not shown) may be attached to the projection lens (6) by hand instead of the shutter mechanism (5). However, when the cap is made of metal, the cap becomes too hot due to the light from the light source (1) and cannot be held with bare hands. When the cap is made of a synthetic resin, the cap may be heated and deformed. In addition, the cap may be dropped and lost. In view of such a problem, a metal shutter mechanism (5) is provided. Further, since the shutter mechanism (5) is provided in the cabinet (2), there is no possibility that the finger is caught between the movable shutter plates (51) and (51).
[0021]
In recent years, in a movie theater or a large hall, a projection device and a projector are provided side by side, and a movie image by a projector, a commercial image by a projection device, and the like are alternately projected on the same screen (20). In some cases, two projectors are provided side by side, and still images for presentation and moving images such as video images are alternately projected. In such a case, there are many cases where the image is temporarily not projected while the light source (1) is irradiated, and the shutter mechanism (5) of the present example is used for the liquid crystal panels (7) and (7a) of the projection device used in this way. Useful for protection of (7b).
[0022]
The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. In addition, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.
[Brief description of the drawings]
FIG. 1 is a plan view showing the inside of a projection apparatus.
FIG. 2 is a plan view of a polarizing beam splitter.
FIG. 3 is a perspective view of a mechanism for moving a movable shutter plate.
FIG. 4 is a perspective view of another mechanism for moving a movable shutter plate.
FIGS. 5A, 5B, and 5C are plan views showing an opening / closing operation of a shutter plate. FIGS.
FIG. 6 is a plan view showing a shutter mechanism in which two movable shutter plates are stacked.
FIG. 7 is a plan view showing another shutter mechanism.
FIG. 8 is a plan view showing another shutter mechanism.
FIG. 9 is a cross-sectional plan view showing a projection device that diffuses light from a light source and is air-cooled by a fan.
10 is an enlarged view of the light shielding strip of FIG. 9;
FIG. 11 is a plan view showing the inside of another projection apparatus.
FIG. 12 is a plan view showing the inside of a conventional projection apparatus.
FIGS. 13A and 13B are exploded perspective views of the liquid crystal panel, FIG. 13A shows a state where no electric field is applied to the liquid crystal panel, and FIG. 13B shows an electric field applied to the liquid crystal panel. Each state is shown.
FIG. 14 is a perspective view of an apparatus including a conventional shutter mechanism.
[Explanation of symbols]
(1) Light source
(2) Cabinet
(5) Shutter mechanism
(7) LCD panel
(8) Polarizing beam splitter
(9) Fan
(51) Movable shutter plate
(52) Shading strip
(53) Slit
(60) Dichroic mirror
(61) Dichroic mirror
(8) Polarizing beam splitter
(80) Partially transmitting prism
(81) Mirror body
(95) Control circuit

Claims (1)

A pair of lens array bodies through which light emitted from the light source passes, a polarization beam splitter that aligns the light from the pair of lens array bodies to either P wave or S wave, and light from the polarization beam splitter is irradiated; In the projection apparatus including the liquid crystal panel having the polarizing plate, the projection apparatus further includes a shutter mechanism that shields light from the light source, and the shutter mechanism includes a pair of slits formed between the light shielding stripes and the light shielding stripes. The shutter plate is configured such that one shutter plate is fixedly arranged on the incident side of the polarization beam splitter, and the other shutter plate has irregular reflection means for irregularly reflecting light from the light source, and between the pair of lens array bodies, It deployed movably by a drive mechanism, the movement of the other shutter plate by the drive mechanism, when the light from the light source is configured to be light shielding The, the plurality of fins are cooled by the fan, the projection apparatus characterized by being configured such that light impinges irregularly reflected by diffuse reflection means of the other shutter plate.

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