JP2000206618A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use luminous flux emitted from a lamp. SOLUTION: A PBS plate 11 and a reflection mirror 12 are arranged so as to form mutually different angles with respect to the optical axis of the lamp. The end part of the mirror 12 opposed to a first lens array is provided with an interval corresponding to the divergent angle of a lens cell 4a and the end part thereof opposed to a second lens array is provided with an interval corresponding to the pitch of the lens cells 4a and 4b. Besides, the centers of the curvature of a lens cell 2a and the cells 4a and 4b are decentered with respect to the optical axis so that the luminous flux being in parallel with the optical axis can be emitted from the cells 4a and 4b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device used for an illumination system such as a liquid crystal projector.

[0002]

2. Description of the Related Art FIG. 6 is a view for explaining an example of the configuration of an optical system of a liquid crystal projector using a transmission type liquid crystal panel. The lamp 50 includes, for example, a parabolic reflector 50a, and is capable of outputting a light beam (non-polarized light) output from the light emitting unit 50b to the front. The luminous flux output from the lamp 50 is applied to a liquid crystal panel 56.
, A plurality of lens cells 51a, 51a, 51a,...
The light is divided and condensed by the first lens array 51 formed by. Further, the light is converted into linearly polarized light by the polarization conversion unit 52, and the plurality of lens cells 53a, 53
are condensed by the second lens array 53 in which b, 53a, 53b,... are formed.

As will be described later, each of the lens arrays constituting the second lens array 53 receives a light beam that has been converted into linearly polarized light through the polarization conversion unit 52. That is, for example, the lens cell 53a,
53a, 53a... Are transmitted through the PBS plate 61, and are reflected by the lens plate 53b, 53b, 53b. The light beam polarized and converted by the plate 63 is made incident. The luminous flux condensed by the second lens array 53 is made to enter the irradiated area of the liquid crystal panel 56 via the first condenser lens 54 and the second condenser lens 55. The liquid crystal panel 56
Is supplied with a drive signal corresponding to a video signal through a path (not shown), and optical modulation is performed based on the drive signal.

As described above, the liquid crystal projector device forms an image by efficiently using the light beam emitted from the lamp 50 by the optical elements such as the lens arrays 51 and 53, the polarization conversion section 52, and the condenser lenses 54 and 55. Have been able to.

FIG. 7 is a schematic diagram for explaining an optical path passing through the first lens array 51, the polarization conversion section 52, and the second lens array 53. The first lens array 51, the polarization conversion section 52, and the second Of the lens array 53 of FIG. As shown in FIG. 7, the polarization conversion unit 52 receives the light beam collected by the lens cell 51a,
(Polarization Beam Splitter) plate 61, reflection mirror 6
It is constituted by a half-wave plate 63. PBS
The plate 61 has, for example, a configuration in which a PBS film is deposited on a glass plate, performs polarization separation by reflecting or transmitting incident light, and outputs linearly polarized light such as an S-polarized wave or a P-polarized wave. It is configured. Therefore,
The PBS plate 61 is arranged at a required angle with respect to the optical axis so that non-polarized light supplied from the lens cell 51a can be efficiently separated.

For example, the light is condensed by the lens cell 51a, and P
The P-polarized wave transmitted through the BS plate 61 is incident on the lens cell 53a (hereinafter, an optical path transmitted through the PBS plate is also referred to as a transmitted optical path in this specification). The S-polarized wave reflected by the PBS plate 61 reaches the reflection mirror 62 disposed parallel to the PBS plate 61 and is bent in the optical path. And enters the lens cell 53b (hereinafter, in this specification, PB
An optical path passing through the S plate is also referred to as a transmitted optical path, and an optical path reflecting the PBS plate is also referred to as a reflected optical path). The half-wave plate 63 and the lens cells 53a and 53b are, for example, PB
It is formed at a pitch corresponding to the optical path of the light beam incident from the S plate 61 and the reflection mirror 62. That is, the arrangement interval between the PBS plate 61 and the reflection mirror 62 is, for example, a half-wave plate 63,
And the pitch of the lens cells 53a and 53b. As a result, only one of, for example, an S-polarized wave or a P-polarized wave, which is linearly polarized light, is emitted from the second lens array 53, and the lamp 50
Thus, an image can be formed on the liquid crystal panel 56 by effectively using the light flux from the liquid crystal panel 56.

[0007]

However, the PBS plate 61
If the reflection mirror 62 and the reflection mirror 62 are arranged in parallel with each other so as to correspond to the pitch of the half-wave plate 63 and the lens cells 53a and 53b, the divergence angle of the light beam passing through the lens cell 51a is restricted. For this reason, for example, as shown in a circle surrounded by a broken line in FIG. 8, a part of the light beam that has passed through the lens cell 51 a is changed to the lens cell 51 a side end of the reflection mirror 62 and the lens cell of the PBS plate 61. The light beam is cut off at the end on the 53a side, and a luminous flux that cannot contribute to image formation occurs. Also,
The light beam transmitted through the PBS plate 61 is indicated by a broken line b as shown by a solid line a in FIG. 8 depending on the thickness of the glass plate constituting the PBS plate 61 and the refractive index of the PBS film. It does not coincide with the center of the cell 53a.
That is, since the light beam passing through the center of the lens cell 51a does not pass through the center of the lens cell 53a, the liquid crystal panel 56
In this case, the center position of the light beam is shifted. As a result, illumination is performed such that a position off the center of the lens cell image is centered, so that there is a problem that the light flux from the lamp 50 cannot be used efficiently and effectively.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides at least a light source, light modulating means for irradiating light from the light source through a required optical system, In an optical device of a projector device having a projection unit for projecting a light beam modulated by a light modulation unit, a plurality of lens cells having a shape substantially similar to a modulation region of the light modulation element allow a non-light source from the light source to be modulated. A first lens array capable of splitting and condensing polarized light, and a plurality of lens cells corresponding to a plurality of lens cells formed in the first lens array, and divided by the first lens array. A second lens array configured to be capable of condensing the collected light, and the first and second lens arrays are arranged between the first lens array. A polarization conversion unit that converts the emitted non-polarized light beam into a light beam in one of the polarization directions and outputs the converted light beam, wherein the polarization conversion unit sets a required angle with respect to the light beam from the first lens array. It is arranged by
Polarization separating means for transmitting the first polarized light of the incident non-polarized light, outputting the first polarized light to the first lens cell of the second lens array, and performing polarization separation by reflecting the second polarized light. Reflecting means for reflecting the second polarized light reflected by the polarized light separating means to a second lens cell adjacent to the first lens cell in a second lens array; and reflecting by the reflecting means. The polarized light separating means and the reflecting means are arranged at different angles with respect to the optical axis of the light source by a half-wave plate for converting the second polarized light into the first polarized light.

According to the present invention, the polarization separating means and the reflecting means are arranged at different angles with respect to the optical axis of the light source, so that, for example, the divergence angle of the lens cell of the first lens array is determined. To be able to respond,
It becomes possible to take in more light flux and convert the polarization.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a diagram illustrating a configuration example of a liquid crystal projector device according to the present embodiment. The lamp 1 is configured to have, for example, a parabolic reflector 1a, and can output a light beam (non-polarized light) output from the light emitting unit 1b to the front. The luminous flux output from the lamp 1 is formed by a plurality of lens cells 2a, 2a, 2a,... Having a similar shape to the irradiated area (light modulation area) of the liquid crystal panel 7. The light is divided and condensed by the array 2. Each lens cell 2a, 2a, 2a ...
As will be described later with reference to FIG. 2, the center of curvature is eccentric with respect to the optical axis. Lens cells 2a, 2a, 2a
Are divided into linearly polarized light by the polarization conversion unit 3, and the plurality of lens cells 4a, 4b,.
Are condensed by the second lens array 4 in which 4a, 4b,... Are formed. Each of the lens arrays constituting the lens array 4 receives a light beam that has been converted into linearly polarized light via the polarization conversion unit 3 as described later.

As will be described later in detail with reference to FIG. 2, the polarization converter 3 forms a substantially C-shape in which the PBS plate 11 and the reflection mirror 12 as the polarization separating means are symmetrical about the optical axis. Are located in Then, the reflection mirror 12
The half-wave plate 13 is disposed on the emission side of the. That is, for example, the lens cells 4a, 4a, 4a,.
The light flux (transmitted light path) transmitted through the PBS plate 11 and the lens cells 4b, 4b, 4b,.
The light flux (transmitted light path) that has been polarization-converted in the step is incident. Note that the lens cells 4a and 4b are
Similarly to a, the center of curvature is eccentric with respect to the optical axis (dashed line). The luminous flux condensed by the lens array 4 is made to enter the irradiated area in the liquid crystal panel 7 via the first condenser lens 5 and the second condenser lens 6.

FIG. 2 is a diagram for explaining an example of the configuration of the polarization conversion section 3. As shown in FIG. FIG. 2 shows an optical element disposed on the lower side of the drawing with respect to the optical axis (dashed line) shown in FIG. It should be noted that the optical element disposed above the plane of the drawing with respect to the optical axis (dotted line) also takes an optical path that follows the same optical element.

The polarization conversion section 3 includes, for example, a PBS plate 11, a reflection mirror 12, and the like, similarly to the polarization conversion section 52 shown in FIG.
Although constituted by an optical element such as a half-wave plate 13, in this example, the PBS plate 11 and the reflection mirror 12 are arranged at different angles. The PBS plate 11 is arranged at an angle in consideration of its characteristics in order to perform polarization separation, but the arrangement of the reflection mirror 12 is shifted from a parallel state to this,
That is, the PBS plate 11 and the reflection mirror 12 are arranged at different angles.

The arrangement angle of the reflection mirror 12 is such that the end side opposite to the lens cell 2a on the incident side has a gap corresponding to the divergence angle of the lens cell 2a.
The end side facing the lens cell 4b has a gap corresponding to the pitch of the lens cell 4b. This makes it possible to form a gap d2 wider than the gap d1 on the lens cell 2a side when the PBS plate 11 and the reflection mirror 12 are arranged in parallel. Therefore, it is possible to suppress the divergence of the divergent light of the lens cell 2a due to the end of the reflection mirror 12, and it is possible to take in more light flux into the PBS plate 11.
In FIG. 2, as an example, a schematic diagram in which a relatively large difference is shown between the gap d1 and the gap d2 is shown for convenience, but the actual arrangement angle of the reflection mirror 12 is based on the divergence of the lens cell 2a. Any angle may be used as long as a gap corresponding to the angle can be obtained.

FIG. 3 shows the reflecting mirror 1 as described with reference to FIG.
FIG. 4 is a schematic diagram illustrating an optical path when a light emitting device 2 is arranged. FIG.
As described in the above, the lens cell 2a adjusts the center of curvature with respect to the center of the optical axis to correct the shift of the optical axis due to refraction when the light beam passing through the lens cell 2a passes through the PBS plate 11. It is eccentric to a shaft (not shown). Therefore, the center (corresponding to the optical axis) of the light beam transmitted through the PBS plate 11 can pass through the center of the lens cell 4a. In this case, the amount of eccentricity of the lens cell 2a is set such that a light beam passing through the center of the lens cell 4a can pass through the center of the lens cell 4a on the convex surface side.

The condenser lens 5 shown in FIG.
Are designed such that the focal position for alignment with the condenser lens 6 corresponds to the light modulation area of the liquid crystal panel 7.
For this reason, when the center of curvature of the lens cell 2a is decentered and a light beam (light path on the transmission side) enters the lens cell 4a at an angle, the light beam passing through the center of the lens cell 2a is It does not pass through the center on the panel 7. Therefore, as shown in FIG.
The center of curvature of a is decentered with respect to the optical axis,
The light beam emitted from a is made parallel to the optical axis. Also, by decentering the lens cell 2a,
A light beam having an angle corresponding to the amount of eccentricity also enters the lens cell 4b. For this reason, the center of curvature of the lens cell 4b is also decentered with respect to the optical axis, and a light beam parallel to the optical axis is emitted. Thereby, the light flux condensed by the condenser lenses 5 and 6 has its optical axis passing through the center of the light modulation area of the liquid crystal panel.

By configuring the polarization converter 3 in this manner, more light can be taken in by the PBS plate 11 and the light beam emitted from the center of the lens cell 2a passes through the centers of the lens cells 4a and 4b. Will be able to Therefore, efficient image formation using light from the lamp 1 effectively can be performed.

Hereinafter, modified examples will be described with reference to FIGS. FIG. 4 shows a lens cell 20 corresponding to the lens cell 2a and a lens cell 21 corresponding to the lens cells 4a and 4b.
This is an example in which the centers of curvature of a and 21b are not located on the same optical axis.
Both a and 21b show an eccentric configuration. Even when the centers of curvature are not on the same optical axis in this way, by decentering the lens cell 20, the lens cells 21a and 21b, a light beam parallel to the optical axis can be emitted from the lens cells 21a and 21b. become.

FIG. 5 shows a lens array 2 and a lens array 4.
The example which shifted the relative arrangement | positioning position of this is shown. In the example shown in this figure, the lens cell 30 and the lens cell 31a are configured so as not to be decentered, and the center of the light beam whose optical path is shifted due to refraction when transmitting through the PBS plate 11 is incident on the lens cell 31a. I can do it. Accordingly, the light beam passing through the center of the lens cell 30 can pass through the center of the lens cell 31a, and the light beam parallel to the optical axis is emitted from the lens cell 31a. The lens cell 30 is a lens cell 31
a, and the reflection mirror 12 is also PB
Since it is arranged at an angle different from that of the S plate 11, an angled light beam enters the lens cell 31b. Therefore, the lens cell 31b can emit a light beam parallel to the optical axis by decentering the center of curvature with respect to the optical axis.

As described above, the PBS plate 11 and the reflection mirror 1
2 at different angles with respect to the optical axis,
The amount of light incident on the PBS plate 11 can be increased by suppressing the luminous flux from being bent by the ends of the BS plate 11 and the reflection mirror 12, and the optical axis is tilted by changing the arrangement angle of the reflection mirror 12. In this case, by decentering the center of curvature of the lens cell, a light beam parallel to the optical axis can be emitted from the second lens array.

[0021]

As described above, according to the present invention, the polarization separating means (PBS plate) and the reflecting means (reflecting mirror) are arranged at different angles with respect to the optical axis of the light source, so that the end of the reflecting means is provided. It becomes possible to suppress the eclipse of the luminous flux by the part. As a result, a large amount of light flux contributing to image formation can be taken into the polarization separation means. Further, when the optical axis is tilted by changing the arrangement angle of the reflection means, by decentering the center of curvature of the lens cell, a light beam parallel to the optical axis can be emitted from the second lens array. Become like

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of an optical system of a liquid crystal projector according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an arrangement angle of a reflection mirror shown in FIG.

FIG. 3 is a diagram illustrating an optical path in the polarization conversion unit shown in FIG.

FIG. 4 is a diagram illustrating a modified example of the present invention.

FIG. 5 is a diagram illustrating a modification of the present invention.

FIG. 6 is a diagram illustrating a configuration example of an optical system of a conventional liquid crystal projector device.

FIG. 7 is a diagram illustrating an optical path in the polarization conversion unit shown in FIG.

FIG. 8 is a view for explaining a shift of a light beam in the polarization conversion unit shown in FIG. 6;

[Explanation of symbols]

1 lamp, 2, 4 lens array, 2a, 4a, 4
b, 20, 21a, 21b, 30, 31a, 31b Lens cell, 5, 6 condenser lens, 7 liquid crystal panel, 11 PBS plate, 12 reflection mirror, 13 1/2
Wave plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Sugihara 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Koji Kita 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F term (reference) 2H088 EA13 HA21 HA25 HA28 MA20 2H091 FA07Z FA11Z FA14Z FA26Z FA29Z FA41Z FD12 FD22 LA30 MA07 5C058 AB06 EA11 EA12 EA26 EA51

Claims (5)

[Claims] 1. A projector device comprising at least a light source, a light modulating means for irradiating light from the light source via a required optical system, and a projecting means for projecting a light beam modulated by the light modulating means. In the optical device, a first lens array capable of dividing and condensing non-polarized light from the light source by a plurality of lens cells having a shape substantially similar to a modulation region of the light modulation element; A plurality of lens cells corresponding to the plurality of lens cells formed in one lens array are provided, and the light divided and condensed by the first lens array can be respectively collected. A second lens array, disposed between the first and second lens arrays, and converts the unpolarized light flux condensed by the first lens array into a light flux in one of the polarization directions. Polarization conversion means for converting and outputting the light, wherein the polarization conversion means is disposed at a required angle with respect to the light beam from the first lens array, and the first of the incident non-polarized light. Transmits polarized light, outputs the first polarized light to the first lens cell of the second lens array, and performs polarization separation by reflecting the second polarized light. Reflecting means for reflecting the second polarized light to a second lens cell adjacent to the first lens cell in the second lens array, and applying the second polarized light reflected by the reflecting means to the first lens cell. An optical device, comprising: a half-wave plate that converts the light into polarized light, wherein the polarized light separating means and the reflecting means are arranged at different angles with respect to the optical axis of the light source. 2. An arrangement state of the polarization separating unit and the reflecting unit, wherein an end side facing the first lens array corresponds to a divergence angle of a lens cell formed in the first lens array. An end portion facing the second lens array has a gap corresponding to a pitch of lens cells formed in the second lens array. The optical device according to claim 1. 3. The optical device according to claim 2, wherein a center of curvature of a lens cell of the first lens array is eccentric with respect to an optical axis of the light source. 4. In the second lens array, a lens cell to which a light beam transmitted through the polarization splitting means enters and / or a lens cell to which a light beam reflected by the reflecting means and passing through the half-wave plate enters. 4. The optical device according to claim 3, wherein the center of curvature is decentered with respect to the optical axis of the light source. 5. The first and second lens units such that a light beam passing through the center of the lens cell of the first lens array passes through a center part of the first lens cell after passing through a polarization separation unit. The optical device according to claim 2, wherein a lens array is provided, and a center of curvature of the second lens cell is decentered with respect to an optical axis of the light source.