JP3363774B2 - Projection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection device for projecting an image displayed on a liquid crystal panel or the like onto a screen by using light whose polarization directions are aligned.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, three liquid crystal panels (7) corresponding to R, G, and B which are three primary colors of light.
There has been proposed a projection device including (7a) and (7b), which irradiates these with strong light from a lamp (1), synthesizes light fluxes passing through a liquid crystal panel, and projects an image. Here,
The liquid crystal panel allows only polarized light corresponding to the alignment direction of liquid crystal molecules in the liquid crystal panel to pass therethrough. Therefore, in general, a polarizing plate is sandwiched between the light source and the liquid crystal panel, and only polarized light that can be transmitted through the polarizing plate The panel is illuminated. For polarization, see Figure 8.
As shown in, there is vertical polarization called S wave and horizontal polarization called P wave with respect to the reflecting surface, and the light from the lamp (1) is indefinite polarization in which S wave and P wave are mixed, Since only one polarized light passes through the polarizing plate, the lamp (1)
Only half of the light from the LCD passes through the LCD panel. In view of this point, there has been proposed a device that effectively uses the light from the lamp (1). FIG. 3 is a plan view of the device,
This device is called a prism type, and includes a liquid crystal panel (10) (10a) (10b) and various lenses in a substantially rectangular cabinet (20), and a liquid crystal panel (10) (10a) (10b). This image is projected on the screen (30) by the light from the lamp (1).

The light from the lamp (1) is reflected by the reflector (2) to remove infrared rays and ultraviolet rays.
Via (3), first convex lens body (4), second convex lens body
It is collected by (5). The convex lens bodies (4) and (5) are formed by arranging a plurality of convex lenses (50) vertically and horizontally (see FIG. 4), and the light condensed by the biconvex lens bodies (4) and (5) is a prism array.
It is incident on (40). FIG. 5 is a perspective view of the prism array (40), and FIG. 6 is a prism array (40) and a biconvex lens body.
It is a top view of (4) and (5). The prism array (40) is an elongated PBS (Polarized Bea) with a polarization separation film (46) inside.
m Splitter) (45) and an elongated mirror body (75) having a reflective film (76) inside are alternately arranged to form a plate-like structure. The PBS (45) and the mirror body (75 ) Is arranged so that the arrangement direction is directed to the left and right in a vertical plane orthogonal to the optical axis. Incidentally, P
BS (45) is disclosed in JP-A-7-294906,
It is well known. Undefined polarization from the lamp (1) is PBS
Upon entering (45), the polarization splitting film (46) of the PBS (45) transmits only the P wave and reflects the S wave by 90 degrees. S reflected
The wave is directly emitted by the reflection film (76) of the adjacent mirror body (75). On the front side of the polarization separation film (46), the polarization plane is 90
A well-known λ / 2 polarizing plate (77) for rotating the PBS (45) is provided integrally with the PBS (45), and the P wave passing through the polarization separation film (46) is λ / 2.
It passes through the polarizing plate (77) and is polarized into S waves. As a result, all the light passing through the prism array (40) is converted into S waves.

As shown in FIG. 3, the light converted into the S wave is inverted by 90 degrees by the total reflection mirror (7) inclined with respect to the optical path. The reflected light is the first dichroic mirror (8)
Allows only B to pass. The B is a cabinet (2
It is reflected by the total reflection mirror (70) located at the back of (0),
It is condensed by the condenser lens (9) and illuminates the liquid crystal panel (10) for blue light. Similarly, G is reflected by the second dichroic mirror (80) and illuminates the liquid crystal panel (10a) for green light, and R is transmitted through the relay lenses (11) and (11a) and is a total reflection mirror (72). After being reflected by, the liquid crystal panel (10b) for red light is irradiated. Each LCD panel (10) (10a) (10
The light radiated to b) is combined by the dichroic prism (12) which transmits G and reflects B and R, and the projection lens (1
The image is enlarged and projected on the screen (30) in 3).

[0005]

The irradiating positions of the liquid crystal panel (10) and the projection lens (13) may be displaced due to dimensional error and mounting error of each lens or mirror in the cabinet (20). In this case, the screen (30) will not be illuminated correctly with the image.
An adjusting mechanism is provided on at least one of the first convex lens body (4) or the second convex lens body (5) that collects the light from (1), and the first convex lens body (4) or the second convex lens body (5) is provided. It is conceivable to correct the optical path by moving the lens in the up / down / left / right directions and the rotation direction. However, the first convex lens body (4) or the second convex lens body
When (5) is adjusted, the light-condensing position of the first convex lens body (4) or the second convex lens body (5) is displaced, and light does not enter the prism array (40) accurately. As a result, the efficiency with which the emitted light is converted into one polarized light is reduced, that is, there is a possibility that light in which the S wave and the P wave are partially mixed is emitted. An object of the present invention is to make the prism array adjustable and prevent the efficiency of conversion into polarized light from decreasing.

[0006]

A projection device includes a lamp (1) which emits indefinite polarized light in which a S wave and a P wave are mixed, and an image irradiated on the lamp (1) on a screen in a cabinet (20). Projection lens (13) for projection, lamp (1) and projection lens
First and second convex lens bodies (4) and (5), which are located on the optical path between (13) and collect light from the lamp (1), and a biconvex lens body (4)
And a prism array (40) which is provided so as to face (5) and converts emitted light into one of S-wave and P-wave.
The prism array (40) has a PBS (45) that emits only one of S-waves and P-waves and a mirror body (75) that polarizes and emits light that has not been emitted by the PBS (45) and that alternates vertically or horizontally. It is arranged in a row. At least one of the first and second convex lens bodies (4) and (5) is provided so that its position can be adjusted in a vertical plane orthogonal to the optical path, and the prism array (40) is a PBS (45).
The position of the mirror body (75) is adjustable along the arrangement direction of the mirror body (75).

[0007]

[Operations and effects] The projection lens (1
Even if the irradiation position of 3) shifts, the first convex lens body (4) or the second convex lens body (4)
By adjusting the convex lens body (5), it is possible to correct the optical path and adjust the irradiation position. Also, the first convex lens body (4)
Or by adjusting the second convex lens body (5), a biconvex lens body
Even if the light collecting positions of (4) and (5) are displaced, if the prism array (40) is adjusted along the arrangement direction of the PBS (45) and the mirror body (75), the biconvex lens body (4) (5) The light emitted from the light reaches the prism array (40) exactly. This allows the prism array
It is possible to prevent the efficiency of conversion into one polarized light at (40) from being reduced, and thus the amount of light emitted from the projection lens (13) is not reduced.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An example of the present invention will be described in detail below with reference to the drawings. The same configurations as those of the related art will be denoted by the same reference numerals and detailed description thereof will be omitted. FIG. 1 is a plan view of the projection device. As in the conventional case, the light from the lamp (1) is reflected by the reflector (2) and passes through a filter (3) for removing infrared rays and ultraviolet rays, and then a first convex lens body (4) and a second convex lens body (4). It is collected by 5). The condensed light enters the prism array (40) arranged in front of the second convex lens body (5), and only the S wave is emitted. Prism Array (40)
Consists of PBS (45) and mirror bodies (75) arranged alternately on the left and right, and emits only S waves. The emitted light is condensed by a condenser lens (6), and then is a total reflection mirror tilted with respect to the optical path.
It is reversed 90 degrees by (7). Only B is allowed to pass through the reflected light by the first dichroic mirror (8), and G and R
Is reflected.

B is reflected by the total reflection mirror (70) located at the back of the cabinet (20) and enters the prism body (12). G is reflected by the second dichroic mirror (80) and irradiates the liquid crystal panel (10a) for green light, and then enters the prism body (12), and R is transmitted through the relay lenses (11) and (11a). After being reflected by the total reflection mirror (72), the liquid crystal panel (10b) for blue light is irradiated. The respective lights are combined by the prism body (12) and reflected toward the projection lens (13).

Here, due to the dimensional error and the mounting error of the first convex lens body (4) and the second convex lens body (5),
Irradiation positions of the liquid crystal panels (10), (10a), (10b) sometimes deviate from the normal positions. In this example, the positions of both the first and second convex lens bodies (4) and (5) can be adjusted in a vertical plane orthogonal to the optical path, and the first convex lens body (4) and the second convex lens body (5) One can be moved only up and down, and the other can be moved only left and right. Further, when the biconvex lens bodies (4) and (5) are adjusted and moved, the converging position of the first convex lens body (4) or the second convex lens body (5) is displaced, and the light is accurately reflected on the prism array (40). There is a risk that the light will not be incident, and as a result, the efficiency of conversion into polarized light will decrease. In consideration of this point, in this example, the prism array (40) is adjusted and moved along the arrangement direction of the PBS (45) and the mirror body (75) to accurately reach the prism array (40). Is characterized by. FIG. 2A is a front view of the adjusting mechanism (25) of the prism array (40) as seen from the lamp (1) side. FIG. 2B is a right side view of the above, and the adjustment plate (29) described later is removed for convenience of explanation. The same adjusting mechanism (25) is used for the first convex lens body (4) and the second convex lens body.
It is also attached to (5), and the first convex lens body (4) and the second convex lens body (5) are attached at positions displaced by 90 degrees in a vertical plane orthogonal to the optical path.

The adjusting mechanism (25) is provided with an opening (27) into which the prism array (40) is inserted, on the side surface of the frame (26) protruding inward from the cabinet (20), and the prism array (4)
The upper and lower ends of (0) are grooves (2
It is sandwiched by 4). A spring piece (28) is provided at the back of the opening (27), and the spring piece (28) has the inserted prism array (40).
Is pressed toward the opening (27). A spring body (not shown) may be provided in the groove (24) and pressed upward or downward to regulate the vertical play.

The prism array (40) extends from the opening (27) to the frame (2
After being inserted into the inside of 6), the opening (27) is closed by the adjusting plate (29). The adjusting screw (35) is screwed into the adjusting plate (29),
The tip of (35) contacts the side surface of the prism array (40). When the adjusting screw (35) is rotated, the prism array (40) moves along the moving direction of the adjusting screw (35). As a result, the prism array (40) is adjusted in the left-right direction, that is, the arrangement direction of the PBS (45) and the mirror body (75). Thereby, even if the first convex lens body (4) or the second convex lens body (5) is displaced, the light accurately reaches the prism array (40). FIG. 7 is a plan view showing a state where the second convex lens body (5) is displaced from the regular position in the left-right direction and the light is displaced from the prism array (40). As shown in FIG. 7, a part of the P wave that has passed through the polarization splitting film (46) does not pass through the λ / 2 polarizing plate (77), and is emitted from the prism array (40) as it is. That is, in the emitted light, the P wave is partially mixed with the S wave. As described above, since the P wave does not pass through the liquid crystal panel, the amount of light that illuminates the liquid crystal panel is reduced.
However, if the prism array (40) can be adjusted to the left and right, all the light from the prism array (40) is converted into S waves, so that the efficiency of conversion into polarized light can be prevented from decreasing. Further, as described above, the adjusting mechanism (25) is provided with a 90-degree offset between the first convex lens body (4) and the second convex lens body (5), so the first convex lens body (4) or the second convex lens body (4) Either one of 5) is adjusted vertically, and the other is adjusted horizontally.

In this example, the prism array (40) is P
Although the BS (45) and the mirror body (75) are arranged left and right, they may be arranged vertically. In this case, the prism array
(40) can be adjusted up and down. In addition, the prism array (4
0) is arranged in front of the second convex lens body (5),
It may be arranged between the first convex lens body (4) and the second convex lens body (5). Furthermore, in this example, the prism array (40)
Although only S wave is emitted, P wave may be emitted. However, the liquid crystal panels (10), (10a), (10b) must pass the P wave.

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. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[Brief description of drawings]

FIG. 1 is a plan view of a projection device.

2A and 2B are views showing an adjusting mechanism, in which FIG. 2A is a front view seen from the lamp side, and FIG. 2B is a side view.

FIG. 3 is a plan view of a conventional projection device.

FIG. 4 is a perspective view of a first or second convex lens body.

FIG. 5 is a perspective view of a prism array.

FIG. 6 is a plan view showing a state in which light is accurately incident on a prism array.

FIG. 7 is a plan view showing a state where light is shifted and incident on a prism array.

FIG. 8 is a conceptual diagram of S waves and P waves.

[Explanation of symbols]

(1) Lamp (4) First convex lens body (5) Second convex lens body (13) Projection lens (20) Cabinet (26) Frame body (35) Adjustment screw (40) Prism array (45) PBS (75) Mirror body

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI G03B 33/12 H04N 5/74 A H04N 5/74 G02B 7/18 A

Claims (3)

(57) [Claims] 1. A lamp (1) which emits indefinite polarization in which a S wave and a P wave are mixed, and a projection lens (13) which projects an image irradiated on the lamp (1) on a screen in a cabinet (20).
Is located on the optical path between the lamp (1) and the projection lens (13),
First and second convex lens bodies that collect light from the lamp (1)
(4) and (5) and a prism array (40) that is provided to face the biconvex lens bodies (4) and (5) and that converts the emitted light into one of S wave and P wave, The prism array (40)
PBS (45) that emits only one of S wave and P wave and PBS
In a projection device comprising mirror bodies (75) for deflecting and emitting light not emitted by (45) alternately arranged vertically or horizontally, the prism array (40) is a PBS (45) and a mirror. A projection device provided so that its position can be adjusted along the arrangement direction of the body (75). 2. The prism array (40) is a cabinet (20).
It is sandwiched by a frame body (26) provided integrally with the frame body, and is urged by a spring member in the frame body (26) in the escape direction from the frame body (26) and screwed into the frame body (26). The projection device according to claim 1, wherein (35) is adjusted by rotating it against the biasing force of the spring member. 3. The projection apparatus according to claim 1, wherein at least one of the first and second convex lens bodies (4) and (5) is provided so that its position can be adjusted in a vertical plane orthogonal to the optical path. .