JPH10246871A - Projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make invisible a shadow part in a polarization beam splitter which has glass plate groups connected. SOLUTION: The projection device is equipped with the polarization beam splitter 2 which passes only the P wave of the light from a light source 1 and a liquid crystal panel 4 irradiated with the light passed through the polarization beam splitter 2. The polarization beam splitter 2 is formed by connecting glass plate groups 3 and 3a, having glass plate whose normals slant at the Brewster angle to the optical axis, one over the other vertically and the glass plate groups 3 and 3a have the tip parts made to abut against each other to form a mountain shape. Convex lenses 60 and 50 are arrayed regularly between a liquid crystal panel 4 and the polarization beam splitter 2 and provided with 1st and 2nd lens bodies 6 and 5 illuminating the entire surface of the liquid crystal panel 4. Both the lens bodies 6 and 5 are provided at the position where a shadow part generated by the abutting part between the glass plate groups 3 and 3a is imaged at both the upper and lower ends of the liquid crystal panel 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection apparatus which irradiates a liquid crystal panel with strong light having a vibrating surface and irradiates an image of the liquid crystal panel onto a screen or the like.

[0002]

2. Description of the Related Art FIG. 7 shows a projection apparatus. In the light from the light source (1), part or all of the vertically polarized S wave is reflected by the polarizing beam splitter (2),
Part of the P wave and the S wave, which are horizontally polarized light, pass. The passing light passes through lens bodies (6) and (5) each having a plurality of convex lenses (60) and (50) arranged regularly, and irradiates the liquid crystal panel (4). The image on the liquid crystal panel (4) is illuminated by irradiation light, and is irradiated on a screen (8) by a projection lens (7). Here, the polarizing beam splitter (2) usually uses a prism in many cases, but in view of cost reduction,
The one shown in FIG. 2 has been proposed.

[0003] In this method, a plurality of glass plates (30) (30) are superposed to form a glass plate group (3), and the glass plate group (3) is formed.
Is tilted corresponding to the Brewster's angle. Here, the Brewster angle means an angle θ represented by n = tan θ, where n is the refractive index of the glass plate (30), and the normal direction of the glass plate (30) and the incident light are When the Brewster angle θ is formed, 100% of the P wave is transmitted and about 1 S wave is transmitted for each glass plate (30).
It is empirically known that 5% reflection occurs. Accordingly, in the glass plate group (3) in which 4 to 5 glass plates (30) are stacked, 100% of the P wave is transmitted and 50% of the S wave is reflected (see Japanese Patent Application Laid-Open No. Hei 3-10218). Polarizing beam splitter
(2) is a pair of glass plate groups (3) and (3a) arranged vertically
The upper end and the lower end of each are abutted. As described above, the cost is reduced by configuring the polarizing beam splitter (2) by the glass plate group (3) in which the plurality of glass plates (30) (30) are combined.

[0004]

As is well known, incident light is
When entering the glass plate (30), it bends and proceeds. In FIG.
Light incident on the lower end of the upper glass plate group (3a) is refracted upward, and light incident on the upper end of the lower glass plate group (3) is refracted downward. When the light hits the end face of the glass plate (30), it is irregularly reflected and hardly passes through the glass plate group (3). Therefore, in the abutting portion of the two glass plate groups (3) and (3a), a shadow portion where light hardly passes is formed as shown by oblique lines in FIG. When this shadow part is incident on the front surface of the convex lens (60) of the first lens body (6), as shown in FIG. Irradiated. As a result, the light use efficiency is reduced, and the screen is darkened when illuminated on the screen (8). An object of the present invention is to make such a shadow part invisible in a polarizing beam splitter in which glass plates are connected.

[0005]

A light source (1) and a polarizing beam splitter that partially separates the light from the light source (1) into S-waves or P-waves and passes all or some of them. (2) and a liquid crystal panel (4) irradiated by light passing through the polarizing beam splitter (2).
Is a glass plate group (3) in which a plurality of glass plates (30) (30) whose normal lines are inclined by Brewster's angle with respect to the optical axis are stacked
(3a) In a projection device with a series of glass plates,
(3) (3a) is formed in a chevron with the tip portions abutting,
A plurality of convex lenses (60) and (50) are regularly arranged between the liquid crystal panel (4) and the polarizing beam splitter (2),
First and second lens bodies (6) and (5) are provided so that each convex lens (60) (50) can irradiate the entire surface of the liquid crystal panel (4).
(6) and (5) are provided at positions where the shadow portions generated from the butted portions of the glass plate groups (3) and (3a) are imaged on the upper and lower ends of the liquid crystal panel (4).

[0006]

[Operation and Effect] The shadow portion generated from the butted portion of the glass plate groups (3) and (3a) is controlled by the first and second lens bodies.
An image is formed on the upper and lower ends of the liquid crystal panel (4). Therefore, even if the image of the liquid crystal panel (4) is illuminated on the screen, no shadow appears on a prominent portion on the screen, and an image without a sense of incongruity can be obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described below with reference to the drawings. The same components as those of the related art will be described using the same reference numerals. FIG. 1 is a side view of the projection device. light source
The light from (1) is reflected by the reflector (10), travels straight, and enters the polarization beam splitter (2) as in the related art. The incident light is reflected by a polarizing beam splitter (2).
The wave and a part of the S wave are allowed to pass, and the S wave is partially reflected. The light that has passed through the polarizing beam splitter (2) is converted into a first lens body (6) (see FIG. 3) in which a plurality of convex lenses (60) (60) are regularly arranged, and a first lens body (6). Incident on a second lens body (5) in which the same number of convex lenses (50) (50) are arranged.

The light from the light source (1) is transmitted to two lens bodies (6).
Irradiation using (5) is because the light reflected by the reflector (10) is not perfectly parallel light, so that the irradiation range is reliably set by the two lens bodies (6) and (5). It is. The light that has passed through the second lens body (5) is transmitted to the liquid crystal panel (4).
And an image on the liquid crystal panel (4) is irradiated on a screen (8) by a projection lens (7). Usually LCD panel
Although a polarizing plate is provided immediately before (4), if only the P-wave is allowed to pass through only the polarizing plate, most of the light from the light source (1) irradiates the polarizing plate, and the temperature of the polarizing plate is reduced. Will be higher. Therefore, there is a risk of causing a failure of the polarizing plate.
In order to prevent this possibility, the P wave and the S wave are separated in advance on the upstream side of the polarizing plate.

As shown in FIG. 6, each convex lens (60) of the first lens body (6) has a different curvature radius center position from the center to the outer periphery of the first lens body (6). Are located. As the focal position P of each convex lens (60) is closer to the outer peripheral portion of the first lens body (6), the convex lens (60)
It is set closer to the optical axis (15) with respect to the horizontal plane Z including the center. In addition, the bulging direction of the convex lens of the second lens body (5) is opposite to that of the first lens body (6), but has the same configuration as the first lens body (6). By arranging convex lenses of such a special shape, the first and second lens bodies (6)
The convex lenses (60) and (50) of (5) illuminate the entire surface of the liquid crystal panel (4). That is, each convex lens (60) (5
Light passing through 0) overlaps.

As shown in FIG. 2, the polarizing beam splitter (2) is composed of a plurality of glass plates (3) in which a plurality of glass plates (30) (30) are superposed one on another. As described above, in the abutting portions of the glass plate groups (3) and (3a) vertically adjacent to each other, shadowed portions where light does not pass occur as shown by oblique lines. In the present example, the two lens bodies (6) and (5) are arranged so that the shadow portion appears on the upper and lower ends of the liquid crystal panel (4). As shown in FIG. 4, the butted portions of the glass plates (3) and (3a) in the polarizing beam splitter (2) face the upper and lower ends of each convex lens (60) of the first lens body (6). I have.
In the projection device according to FIG. 4, light incident on the center of the convex lens (60) of the first lens body (6) passes through the center of the second lens body (5) as shown by a dotted line. LCD panel
The light enters the center of (4).

As described above, the first and second lens bodies (6) and (5)
Each of the convex lenses (60) and (50) illuminates the entire surface of the liquid crystal panel (4). Light incident on the upper and lower ends of each convex lens (60) of the first lens body (6) is reflected by each convex lens (50) of the first lens body (6) and the second lens body (5) as shown by a solid line. , Images are formed on the upper and lower ends of the liquid crystal panel (4). That is, the shaded portion of the polarizing beam splitter (2) is imaged on the upper and lower ends of the liquid crystal panel (4) as shown by oblique lines in FIG. 5, and is not displayed on the screen (8). As a result, it is possible to prevent an image having a strange feeling from being displayed on the screen (8).

In the above example, the number of glass plate groups (3) and the first
The number of the convex lenses (60) of the lens body (6) is the same, but it is only necessary that the butted portions of the glass plate groups (3) and (3a) correspond to the upper and lower ends of the convex lens (60). Need not be.

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 a side view of a projection device.

FIG. 2 is a side view showing an arrangement of a group of glass plates in a polarizing beam splitter.

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

FIG. 4 is a diagram showing an irradiation state on a liquid crystal panel.

FIG. 5 is a front view of the liquid crystal panel in which shadows are projected at upper and lower ends.

FIG. 6 is a side view of the first lens body.

FIG. 7 is a side view of a conventional projection device.

FIG. 8 is a side view showing an irradiation state on a first lens body of the above.

FIG. 9 is a front view of the liquid crystal panel in which a shadow is projected on a screen.

[Explanation of symbols]

 (1) Light source (2) Polarizing beam splitter (3) Glass plate group (4) Liquid crystal panel (5) Second lens body (6) First lens body

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H04N 5/74 H04N 5/74 A

Claims (2)

[Claims] 1. A light source (1), a polarizing beam splitter (2) that partially separates light from the light source (1) into an S-wave or a P-wave, and passes one of them, and the polarizing beam splitter (2). 2) a liquid crystal panel (4) illuminated by the light passing through,
The polarizing beam splitter (2) is composed of a glass plate group (3) (3a) in which a plurality of glass plates (30) (30) whose normal lines are inclined by the Brewster angle with respect to the optical axis are stacked one on top of the other. In the projection device described above, the glass plates (3) and (3a) are formed in a mountain shape with their tips abutting each other, and a plurality of convex lenses (3) are provided between the liquid crystal panel (4) and the polarizing beam splitter (2). 60) (50) are arranged regularly,
First and second lens bodies (6) and (5) are provided so that each convex lens (60) and (50) can irradiate the entire surface of the liquid crystal panel (4), and both lens bodies (6) and (5) are glass plates. A projection device provided at a position where a shadow portion generated from an abutting portion of the groups (3) and (3a) is imaged on both upper and lower ends of the liquid crystal panel (4). 2. The first and second lens bodies (6) and (5) are formed by arranging the same number of convex lenses (60) and (50), respectively, and a glass plate group (3).
The projection device according to claim 1, wherein the butted portion of (3a) faces the upper and lower ends of the convex lenses (60) and (50).