JP3519964B2 - 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 that projects an image on a screen with strong light.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a projection device which projects an image on a screen by irradiating a liquid crystal panel with strong light from a light source (35). FIG. 4 is a plan view showing the basic configuration of such a projection device. Light source provided on the chassis (3)
The light from (35) is reflected by the reflector (36) and is condensed on the first and second integrator lens bodies (4) and (5) and the condenser lenses (51) and (52), and the liquid crystal panel (7). ) Is irradiated. The first and second integrator lens bodies (4) and (5) are configured by arranging a plurality of lenses (50) and (50) vertically and horizontally (see FIG. 5).
The light condensed on the central lens (50) of the first integrator lens body (4) is focused by the central lens (50) of the second integrator lens body (5), Irradiate the entire surface of the panel (7). First integrator lens body
The light focused on the peripheral lens (50) of (4) is the corresponding peripheral lens (50) of the second integrator lens body (5).
Focused inside, LCD panel by condenser lens (52)
Irradiate the entire surface of (7). This configuration is called integrator illumination and is a known technique (Japanese Patent Laid-Open No. 5-346557).
No.). In the following description, a surface including the optical axis of the light source (35) and perpendicular to the upper surface of the chassis (3) is called a vertical surface, and a surface orthogonal to the vertical surface and parallel to the upper surface of the chassis (3) is called a horizontal surface.

In FIG. 4, light is incident on the lens (50) of the first integrator lens body (4) not only from the optical axis direction but also from a direction inclined with respect to the optical axis. The light incident on the periphery of the lens (50) of the first integrator lens body (4) is
The light enters the lens (50) of the second integrator lens body (5) at an angle of θ3 with respect to the optical axis. Therefore, the light emitted from the lens (50) of the first integrator lens body (4) at an angle larger than θ3 does not accurately enter the corresponding lens (50) of the second integrator lens body (5). The state in which light does not exactly enter the target range is called the kicked state.
The distance between the first and second integrator lens bodies (4) and (5) is L
3 and the width of the lens (50) of the first integrator lens body (4) is R4, the angle θ3 is represented by θ3 = ARCTAN (R4 / 2 × 1 / L3), and the larger R4 is, the larger θ3 is. It is effective in preventing kicking. In addition, R3 is a liquid crystal panel (7)
The width of the irradiation range, the distance between the second integrator lens body (5) and the condenser lens (51) is L4, and the condenser lens is
If the distance from (51) to the liquid crystal panel (7) is L2, it is expressed by R3 = b × R4 × (L2 + L4) / L3 (b is a correction coefficient considering the influence of refraction of the condenser lens). When is transformed, R4 / L3 = R3 / (b × (L2 + L4)). Comparing the expressions with each other, the smaller L2 is,
It can be seen that θ3 becomes large and is effective in preventing kicking. The distance L2 is the distance until the light focused by the second integrator lens body (5) is diffused by the condenser lens (51) and reaches the liquid crystal panel (7), and thus is determined by the condenser lens (51). It If L2 is shortened,
According to the equations, θ3 increases, but the irradiation range of the liquid crystal panel (7) decreases.

As is well known, the light from the light source (35) is an indefinite polarized light in which two polarizations of S wave and P wave whose polarization planes are deviated from each other by 90 degrees are combined, and the liquid crystal panel (7) is S. Only one of wave or P wave is allowed to pass. Therefore, if the liquid crystal panel (7) is irradiated with undefined polarized light as it is, the light utilization efficiency decreases. Therefore, as shown in FIG. 6, a PBS (Polarized Beam Splitter) (6) is provided between the first integrator lens body (4) and the second integrator lens body (5) to provide the second integrator lens body. There is one that aligns the light emitted from (5) with any polarized light corresponding to the liquid crystal panel (7) and efficiently irradiates the liquid crystal panel (7).

FIG. 6 is a plan view of the PBS (6) and the first and second integrator lens bodies (4) and (5). The PBS (6) allows the passage of P waves and the spectroscopic plate (60) that reflects S waves to the side
The mirrors (61) for reflecting the S-wave reflected by the spectroscopic plate (60) forward are arranged alternately in a horizontal row at equal intervals. A λ / 2 polarizing plate (62) for changing the polarization plane of light by 90 degrees is provided in front of the spectroscopic plate (60). The light incident on the PBS (6) from one lens (50) of the first integrator lens body (4) is divided into light emitted from the λ / 2 polarizing plate (62) and light emitted from the mirror (61). The light is divided into hands and emitted, and the respective lights enter the second integrator lens body (5). Therefore, in order for the lens (50) of the second integrator lens body (5) to reliably collect light, the lateral width of the lens (50) is half the lateral width of the lens (50) shown in FIG. It is necessary to provide in 2.

[0006]

The liquid crystal panel (7) often has a screen aspect ratio of 3: 4, and in a projection device that does not use the PBS (6), the first and second integrator lenses are used. The lenses (50) of the bodies (4) and (5) generally have an aspect ratio of 3: 4 as shown by the dotted line in FIG. 9 corresponding to the liquid crystal panel (7). That is, since the lens (50) of the first and second integrator lens bodies (4) and (5) has a smaller vertical width than a horizontal width, a kicking phenomenon is likely to occur in a vertical plane rather than a horizontal plane. It was However, when the PBS (6) is provided, the lateral width of the second integrator lens body (5) becomes half as compared with the case where the PBS (6) is not provided. This is shown in FIG.
As indicated by the alternate long and short dash line, the effect is equivalent to halving the width of the lens (50) of the first integrator lens body (4) without providing the PBS (6). The aspect ratio of 50) is 3: 2.

As a result, from the above equation, R4 becomes smaller in the horizontal plane, so that the angle θ3 becomes smaller and the incident light is easily kicked in the horizontal plane. In particular, in the lens (50) with an aspect ratio of 3: 4, the short side is 75% of the long side, but in the lens (50) with an aspect ratio of 3: 2, the short side is 66% of the long side. Since the short side is shorter than the long side, it is easier to kick. Therefore, not only the light cannot be efficiently used in the horizontal plane, but also the illuminance on the screen (not shown) cannot be increased. As a countermeasure against this, the lens (50) of the first and second integrator lens bodies (4) (5)
It is conceivable that the width is larger than the vertical width, but it is very difficult due to the opening size of the black matrix described later. The applicant efficiently uses the light by refracting the light in the horizontal plane more than in the vertical plane without changing the distance L2 between the liquid crystal panel (7) and the second integrator lens body (5). I thought of that. The present invention is
In a projection device using integrator illumination, the distance L
The purpose is to effectively use light both in the horizontal plane and in the vertical plane without changing 2.

[0008]

[Means for Solving the Problems] The projection device includes a chassis (3).
A light source (35), an integrator lens body (4) (5) arranged on the optical axis for collecting light from the light source (35), and an integrator lens body (4) (5) for collecting light. It comprises a liquid crystal panel (7) which is illuminated by the emitted light. Two auxiliary lenses (1) and (2) are provided between the liquid crystal panel (7) and one integrator lens body (5) located on the liquid crystal panel (7) side, and the two auxiliary lenses (1) and (2) are arranged on the liquid crystal panel (7). Is a bracket with an opening (80).
The matrix (8) is covered. Located on the liquid crystal panel (7) side
Either before or after the one integrator lens body (5)
Is an indefinite polarized light from the light source (35), which is either S wave or P wave.
A PBS (6) that emits light in a uniform direction is provided. Each of the auxiliary lenses (1) and (2) forms a projecting surface (10) on one of the light incident surface and the light emitting surface, and the projecting surface (10) includes the optical axis and is perpendicular to the chassis (3). The curvature in any one of the plane or the horizontal plane orthogonal to the vertical plane and parallel to the plane of the chassis (3) is formed to be larger than the curvature in the other plane. Two
The light emitted from the integrator lens body (5) on the liquid crystal panel (7) side by the two auxiliary lenses (1) and (2)
The angle of refraction before reaching (7) differs between the vertical plane and the horizontal plane, and the light is emitted from the integrator lens body (5).
Light illuminates the minimum irradiation area of the liquid crystal panel (7) and
Kicking in the hook matrix (8) is also prevented.

[0009]

In the present invention, between the liquid crystal panel (7) and the integrator lens body (5) on the liquid crystal panel (7) side, the projection surface (10) is formed in the vertical plane and the horizontal plane. 2 with different curvatures
The auxiliary lenses (1) and (2) are provided. Therefore, by the two auxiliary lenses (1) and (2), the angle at which the light emitted from the integrator lens body (5) is refracted before reaching the liquid crystal panel (7) is changed in the horizontal plane and the vertical plane. It is possible to prevent the kicked state in either the horizontal plane or the vertical plane. Especially, the integrator lens body
The light emitted from (5) is the minimum irradiation part of the liquid crystal panel (7).
And kicked in the Black Matrix (8)
To be prevented.

[0010]

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 reference numerals are used for the same configurations as the conventional ones. FIG. 3 is a plan view of the projection device. Chassis (3)
Inside, liquid crystal panels (7a) and (7b) corresponding to R and B are arranged with the optical axis of the projection lens (67) interposed therebetween.
Between (7a) and (7b), the prism body (3
0) is deployed. The projection lens (6
A liquid crystal panel (7) corresponding to G is provided on the opposite side of (7). A light source (35) is provided at the optical path entrance to the chassis (3), and a total reflection mirror (75) (76) (77) (78) is provided on the optical path.
The dichroic mirrors (45) and (46) are arranged at an angle of 45 degrees with respect to the optical path. The first and second integrator lens bodies (4) are provided between the light source (35) and the total reflection mirror (75).
In addition to (5) and PBS (6), the first and second features of this example
Auxiliary lenses (1) and (2) are provided.

The light from the light source (35) passes through the first and second integrator lens bodies (4) and (5), the PBS (6), the first and second auxiliary lenses (1) and (2), After being reflected by the total reflection mirror (75), the dichroic mirror (45) allows R to pass therethrough and reflects G and B. R is reflected by the total reflection mirror (76), passes through the condenser lens (52), and illuminates the liquid crystal panel (7a) corresponding to R. R is a prism body (30)
It is reflected by and projected onto the projection lens (67). G
Is reflected by the dichroic mirror (46) and the prism body (3
0), the incident light passes through the prism body (30) as it is, and enters the projection lens (67). B is a total reflection mirror (77)
After being reflected by the (78), it is reflected by the prism body (30) and enters the projection lens (67). The image from the projection lens (67) is projected on the screen (68).

FIG. 1 (a) is a front view showing the arrangement relationship of each lens from the light source (35) to the liquid crystal panel (7) in this example,
FIG.1 (b) is a top view same as the above. For convenience of explanation, PB
The illustration of S (6) is omitted. In this example, two auxiliary lenses (1) and (2) are arranged on the optical axis between the second integrator lens body (5) and the liquid crystal panel (7), and the light is reflected on a vertical plane in a horizontal plane. The feature is that the light is refracted inward more largely than inward, and the light is effectively used in the horizontal plane. The first auxiliary lens (1) is provided between the second integrator lens body (5) and the liquid crystal panel (7).
And a second auxiliary lens (2) located closer to the liquid crystal panel (7) than the first auxiliary lens (1) is provided. As shown in FIG. 2, both auxiliary lenses (1) and (2) are integrally provided with a projecting surface (10) bulging in an arc shape on one surface of a flat lens (11), and the projecting surface (10) is It extends along the longitudinal direction of the flat lens (11). In other words, both auxiliary lenses (1) and (2) are cylindrical lenses in which one surface on the light incident side or the light reflecting side is flat and the other surface is swollen. First auxiliary lens (1)
Is the direction in which the projecting surface (10) extends in the lateral direction orthogonal to the optical axis,
The second auxiliary lens (2) has the projecting surface (10) extending in the vertical direction along the vertical surface. That is, both auxiliary lenses
(1) and (2) are offset from each other by 90 degrees about the optical axis. The first auxiliary lens (1) has a curvature of 0 in the horizontal plane and an infinitely large focal length, so that it has no condensing effect. Further, since the second auxiliary lens (2) has a curvature of 0 in the vertical plane and an infinitely large focal length, there is no light collecting effect, and the first auxiliary lens (1) collects light in the vertical plane. .

(Optical Path in Vertical Plane) As shown in FIG. 1 (a),
The light from the light source (35) passes through the first and second integrator lens bodies (4) and (5) in the vertical plane, then is condensed and emitted by the first auxiliary lens (1), and then the second light is emitted. Pass through the auxiliary lens (2). As described above, the second auxiliary lens (2) has an infinitely large focal length in the vertical plane.
The light is not refracted within (2). As a result, the first auxiliary lens
The light from (1) passes through the second auxiliary lens (2) and illuminates the liquid crystal panel (7).

(Optical Path in Horizontal Plane) As shown in FIG. 1 (b),
The light from the light source (35) enters the first auxiliary lens (1) after passing through the first and second integrator lens bodies (4) and (5) in the horizontal plane. As mentioned above, the first auxiliary lens (1)
Since the focal length is infinitely large in the horizontal plane, the light reaches the second auxiliary lens (2) without being refracted in the first auxiliary lens (1). The light reaches a position near the periphery from the center of the second auxiliary lens (2), but at this position, the normal direction S1 of the projecting surface (10) is inclined with respect to the optical axis. Generally, when light is incident on a convex lens where the normal direction is inclined with respect to the optical axis and when light is incident on a position where the normal direction is substantially parallel to the optical axis, Since the light is refracted when it is incident on the inclined portion, the light is largely refracted inward when the light is incident on the peripheral portion of the second auxiliary lens (2). Therefore, in the horizontal plane, the second auxiliary lens (2) has a condensing effect, and the distance L5 from the second auxiliary lens (2) to the liquid crystal panel (7) is shorter than the distance L2. 2 The light emitted from the auxiliary lens (2) illuminates the minimum irradiation part of the liquid crystal panel (7).

As described above, the second auxiliary lens (2) largely refracts light in the horizontal plane inward. This may reduce the irradiation range. The first solution to this problem
The width of the lens (50) of the integrator lens body (4) is increased, and in accordance with this, the first integrator lens body (4)
The lens (50) has a large width, specifically an aspect ratio of 3:
It is possible to set it to about 3. As a result, the angle θ3 (see FIG. 1B) of the light incident on the lens (50) of the second integrator lens body (5) also becomes large, and the light can be effectively used.

In this example, since the purpose is to eliminate the kicked state in the horizontal plane, the first and second integrator lens bodies (5) are provided without providing the auxiliary lenses (1) and (2). It is also possible to increase the width of the lens (50). But,
Increasing the width of the lens (50) causes inconvenience when illuminating the liquid crystal panel (7), specifically, the liquid crystal panel (7).
The black matrix covering the light further kicks the light in the vertical plane. FIG. 7 is a perspective view of the sheet-like black matrix 8 and the TFT 72 on the liquid crystal panel 7. As is well known, the liquid crystal panel (7) has elongated electrodes (71) arranged in a grid on a transparent substrate (70), and each grid corresponds to one pixel. TFTs (Thin Film Transisit
or) (72). When the TFT 72 is directly exposed to strong light, it is thermally damaged. Therefore, a black matrix 8 having an opening 80 is provided on the incident side to block the light to the TFT 72. Light passes through the opening (80) and passes through the T of the transparent substrate (70).
Irradiate a place other than FT (72).

This black matrix (8) and opening (80)
The area ratio is substantially determined by the size of the liquid crystal panel (7), and the area shielded by the black matrix (8) is 40 to 60% of the irradiation area of the liquid crystal panel (7). As shown in FIG. 10, it is the microlens (81) arranged on the incident side of the black matrix (8) that reduces the light blocked. Light is collected by the microlens (81) and passes through the opening (80). However, in order to obtain the effect of high brightness with the microlens (81), the light from the microlens (81) needs to be within an angle θ1 from the optical axis. Micro lens (81) and black matrix
If the distance to (8) is L1 and the width of the opening (80) is R1,
The angle θ1 is represented by θ1 = ARCTAN (R1 / 2 × 1 / L1). Even if light is emitted from the microlens (81) at an angle larger than θ1, the black matrix
It is shielded from light by (8). If L1 is shortened, θ1
However, the projection lens (67) (see FIG. 3) causes light to be blocked, and even if L1 is shortened, a harmful effect occurs.
A black matrix (8) and an aperture corresponding to one pixel of a 0.9-inch XGA liquid crystal panel used in such a projection device
The dimensions of (80) are shown in FIG. As can be seen from FIG. 8, the openings 80 in the horizontal direction are about 83% of the black matrix 8, while the openings 80 are about 53% in the vertical direction. That is, in the liquid crystal panel (7), light is easily kicked in the vertical plane, so that in the conventional projection device, the width of the lens (50) of the first and second integrator lens bodies (5) is wide. If is set to be large, light may be kicked not only in the vertical plane but also in the horizontal plane. Therefore, the auxiliary lens in this example
It is difficult to increase the lateral width of the lens (50) of the first and second integrator lens bodies (5) without using (1) and (2).

In this example, it is also conceivable to manufacture special auxiliary lenses having different refraction angles in a vertical plane or a horizontal plane and replace them with the auxiliary lenses (1) and (2). However, the two auxiliary lenses (1) and (2) are so-called cylindrical lenses having a convex surface (10) bulging in an arc shape on one surface, and are easy to manufacture. Therefore, an increase in manufacturing cost can be prevented.

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. For example, although the PBS (6) emits light by aligning it with S waves, it may emit light by aligning it with P waves. Also,
In this example, both the auxiliary lenses (1) and (2) have the projecting surface (10) facing the light source (35) side, but they may face the liquid crystal panel (7) side. Further, the surfaces of the auxiliary lenses (1) and (2) opposite to the projecting surface (10) are flat, but they may be formed with a curvature smaller than that of the projecting surface (10).

[Brief description of drawings]

FIG. 1 shows a positional relationship between a light source, first and second integrator lens bodies, and an auxiliary lens, (a) is a front view, and (b) is a plan view.

FIG. 2 is a perspective view of first and second auxiliary lenses.

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

FIG. 4 is a side view showing a basic configuration of a conventional projection device.

FIG. 5 is a perspective view of an integrator lens body.

FIG. 6 is a plan view of a PBS and first and second integrator lens bodies.

FIG. 7 is a perspective view of a transparent substrate and a black matrix.

FIG. 8 is a plan view showing dimensions of a black matrix and openings corresponding to one pixel.

FIG. 9 is a front view showing a lens of an integrator lens body.

FIG. 10 is a side sectional view of a black matrix and a microlens.

[Explanation of symbols]

(1) First auxiliary lens (2) Second auxiliary lens (3) Chassis (4) First integrator lens body (5) Second integrator lens body (6) PBS (7) LCD panel (10) Protruding surface

Claims (2)

(57) [Claims] 1. A light source (35), an integrator lens body (4) (5) arranged on an optical axis for condensing light from the light source (35), and an integrator lens body (1) on a chassis (3). 4) (5)
In a projection device equipped with a liquid crystal panel (7) that is illuminated by the light condensed by, the space between one integrator lens body (5) located on the liquid crystal panel (7) side and the liquid crystal panel (7) Two auxiliary lenses (1) and (2) are provided on the liquid crystal panel (7), and an opening (8
One of the integrators located on the liquid crystal panel (7) side covered with the black matrix (8) forming (0)
The indefinite polarized light from the light source (35) may be placed either before or after the body (5).
PBS (6) that emits either S-wave or P-wave
The auxiliary lenses (1) and (2) each have a projecting surface (10) formed on one of a light incident surface and a light emitting surface, and the projecting surface (10) includes an optical axis and a chassis (3 ) Perpendicular to the plane or orthogonal to the vertical plane
The curvature in one of the horizontal planes parallel to the (3) plane is formed to be larger than the curvature in the other plane, and the liquid crystal panel (2) is formed by the two auxiliary lenses (1) and (2). The angle at which the light emitted from the integrator lens body (5) on the 7) side is refracted before reaching the liquid crystal panel (7) is different between the vertical plane and the horizontal plane, and the integrator lens body (4) on the light source (35) side is ) Of the incident light
In the Black Matrix (8) as well as kicking prevention
A projection device characterized by being prevented from being kicked . 2. Of the auxiliary lenses (1) and (2), the second auxiliary lens (2) is located closer to the liquid crystal panel (7) than the first auxiliary lens (1), and the first auxiliary lens (1) Has a large curvature of the projecting surface (10) in the vertical plane, and the second auxiliary lens (2) is in the horizontal plane.
The convex surface (10) has a large curvature, and the light is focused on the first auxiliary lens (1) in the vertical plane,
The projection according to claim 1, wherein the second auxiliary lens (2) refracts only slightly, and the second auxiliary lens (2) refracts more inwardly in the horizontal plane than the first auxiliary lens (1). apparatus.