JP3512368B2 - Image 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 an image projection apparatus, and more particularly to an image projection apparatus that realizes high utilization efficiency of illumination light used in a liquid crystal projector or the like.

[0002]

2. Description of the Related Art Color image projectors using a liquid crystal panel are roughly classified into a three-plate type using three liquid crystal panels and a single-plate type using only one liquid crystal panel. The three-plate type has three primary colors of red (R), green (G), and blue (B) (hereinafter, R, G,
(B) An optical system that separates and emits light beams of respective color lights, and a liquid crystal panel including pixels that optically modulate the color lights according to a color image signal and emits the light beams is provided independently for each color light. It is provided and the color lights modulated and emitted from the liquid crystal panel are optically superposed to obtain a full-color composite image.

On the other hand, the single-panel type uses one liquid crystal panel for full color display. For example, one liquid crystal panel provided with a mosaic-like three primary color filter pattern modulates light of each color light. Then, the color image is combined. Compared to the three-plate type, the single-plate type requires only one liquid crystal panel, so it is possible to reduce the size and cost, but
The light emitted from the light source cannot be sufficiently used as a light flux for irradiating the liquid crystal panel, and there is a drawback that the brightness of the screen decreases.

As a device for improving the brightness of this single plate type screen, there is, for example, Japanese Patent Application Laid-Open No. 4-60538, "Color Liquid Crystal Display Device". That is, a plurality of dichroic mirrors having different wavelength ranges are arranged at slight angles different from each other, and the incident white light flux R,
G, B color lights are separated, and R, G, B color lights are applied to one liquid crystal panel from different incident angles, and the polarization direction of each color light is changed pixel by pixel according to the color image signal. By providing the liquid crystal panel with the liquid crystal driving means for performing light modulation, it is possible to contribute to the display with almost no cutting of all the luminous fluxes applied to the liquid crystal panel.

FIG. 8 is an optical path diagram for explaining a main part of an illumination system of an image projection apparatus disclosed as a conventional technique. FIG. 8A is an optical path diagram when the device is viewed from directly above, that is, a horizontal optical path diagram, and FIG. 8B is a vertical optical path diagram. In addition, FIG. 9 shows the first example shown in FIG.
1 is a front view conceptually showing the entire shape of the lens array 43a of FIG. 1, that is, a view seen from the direction along the optical axis.
0 is a view conceptually showing the shape of a cell in which each pixel of R, G, and B of the liquid crystal panel 48 shown in FIG. Figure 8
4, a light source unit 41 includes a light source 41a using a metal halide lamp or the like, and a rotationally symmetrical reflecting mirror 41b having an opening in the light irradiation direction, and 43 indicates a light source unit 4.
1 is a lens array for diffusing the light from 1 to make the in-plane illuminance distribution uniform over the entire surface of the liquid crystal panel 48,
First lens array 43a and second lens array 43b
Consists of. As shown in FIG. 9, the first lens array 43a is formed by arranging a plurality of rectangular lens cells that are similar in shape to the surface of the liquid crystal panel 48 in a two-dimensional manner. It is divided into two and condensed respectively. Further, each lens cell of the second lens array 43b is arranged in a one-to-one correspondence in the vicinity of the focal length of each lens cell of the first lens array 43a.
The small light beams condensed by 3a are directed toward the condenser lens 46 so as to overlap each other.

The condenser lens 46 is for condensing incident light on the liquid crystal panel 48 via the dichroic mirror 47. The dichroic mirror 47 separates incident light into R, G, and B color lights, and is composed of three mirrors, and each of them selectively selects light in any one of R, G, and B wavelength bands. It has the property of reflecting light and transmitting other light. The dichroic mirrors 47 are arranged at mutually different angles with respect to the incident optical axis so that the separated color lights are incident on the liquid crystal panel 48 at mutually different incident angles.

The liquid crystal panel 48 is of a microlens type without a color filter, and has pixel electrodes (not shown) regularly and two-dimensionally arranged corresponding to each pixel of R, G and B, and a liquid crystal layer (not shown). (Not shown), R, G,
Each of the cells of one set of three pixel electrodes B has a condensing microlens (not shown) arranged to face each other. The microlens collects the R, G, and B color lights that are reflected by the dichroic mirror and are incident at mutually different angles, and make them incident on the corresponding pixels of R, G, and B, respectively. By selectively applying an image signal to each of the R, G, and B pixel electrodes, the polarization direction of light passing through the liquid crystal layer is modulated and emitted. By providing a polarizing plate on the emission side, the emitted light is selectively transmitted, and a color image in which the respective color lights are combined is displayed on the screen through the projection lens.

As described above, the light source section 41 generates the
The light flux emitted to the lens array 43 is subdivided into small light fluxes by the individual lens cells of the first lens array 43a so that the entire surface of the liquid crystal panel 48 is uniformly illuminated, and the light fluxes correspond to the second lens array 43b. It is focused on the lens cell position. The small light fluxes emitted by the second lens array 43b so as to overlap the small light fluxes are guided to the condenser lens 46, and are superimposed and imaged on the liquid crystal panel 48 via the dichroic mirror 47. As described above, by using the lens array 43 and the condenser lens 46, the illumination light incident on the liquid crystal panel 48, that is, the incident light can be made uniform over the entire screen of the liquid crystal panel 48, and a bright image can be obtained in every corner of the screen. Can be obtained.

The dichroic mirror 47 provided between the condenser lens 46 and the liquid crystal panel 48 is
The luminous flux incident from the condenser lens 46, that is, the illumination light is separated for each color light of R, G, B, and each color light is reflected at different angles. On the liquid crystal panel 48, one microlens is provided for each cell consisting of a set of R, G, and B pixels, and as described above, each color light incident at the different angle is R. , G, B are focused on the pixels corresponding to each of them, and the parallelism of the color light incident on the liquid crystal panel 48 is determined according to the shape of the pixel. As shown in FIG. 10, when the shape of a cell in which a set of vertically long rectangular R, G, and B pixels is a square pixel, the ratio between the horizontal parallelism and the vertical parallelism of the incident color light is , About 1: 3. Therefore, the overall shape of the lens array 43 is a vertically long rectangular shape similar to the vertically long shape of the R, G, and B pixels as shown in FIG. By adopting this shape, R, G,
Incident light of appropriate color light, that is, irradiation light is condensed on each pixel of B, and a full-color image without unevenness can be obtained.

[0010]

However, as shown in FIG.
In the image projection device according to the related art shown in (1), as described below, there is a problem that light emitted from the light source unit 41 causes a condensing loss in which a part of the light beam is lost at the portion of the lens array 43.

The first problem is that the overall shape of the lens array 43 corresponds to the shapes of the openings of the R, G, and B pixels, and both the first and second lens arrays 43a and 43b are shown in FIG. As shown, the ratio between the horizontal and vertical sides is 1:
It is due to the rectangular shape of 3. Although the light flux from the light source unit 41 is emitted in a circular shape, the light flux in the short side direction, that is, the horizontal direction is blocked in the first lens array 43a, so that the light flux from the light source unit 41 remarkably. Will be missed.

The second problem is the first lens array 43a.
The shape of each of the lens cells is a rectangular shape having a ratio of horizontal side lengths to vertical side lengths of 16: 9 corresponding to the aspect ratio of the screen of the liquid crystal panel 48. There is. At the position of the second lens array 43b,
Although the secondary light source image is generated by the first lens array 43a, the small luminous flux of the secondary light source image incident on the second lens array 43b is collected into the luminous flux in the short side direction of each lens cell, that is, in the vertical direction. Light loss will occur. In addition, the light source unit 4
Also in terms of error sensitivity when the optical axis shift of the light source lamp of No. 1 or the like occurs, it becomes very sensitive to the error in the short side direction of each lens cell, that is, the vertical direction.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is a liquid crystal panel or light modulation that requires that the parallelism of light in the horizontal direction is different from that in the vertical direction. Even when the means is used, the purpose is to achieve high brightness of the projected image by reducing the light-collecting loss of the illumination system of the image projection apparatus and improving the light-collecting performance. That is, in the present invention, the image projection apparatus has the following solving means.

According to a first solution, a pixel for controlling transmitted light corresponding to an image signal is two-dimensionally arranged through a lens array having a plurality of lens cells for forming an image of irradiation light from a light source. the light modulation means is disposed, by projecting light emitted from the light source, the image projecting apparatus for performing image display, pixel shape of the light modulating means comprises a rectangular, incident on the short side direction of the pixel Beam reduction means for reducing the luminous flux width
And for collecting the irradiation light on the light modulating means.
At the focal position on the lens array side of the condenser lens,
Blocks the light flux diffusing in the long side direction of the pixel of the light modulator
It has a diaphragm .

[0015] The second solution is, first solution odor <br/> Te, in the optical path between said lens array the light modulating means, is to have the beam reduction means.

A third solving means is that, in the first or second solving means, the beam reducing means is composed of a cylindrical convex lens and a cylindrical concave lens having a curvature in a short side direction of a pixel of the light modulating means.

[0017] A fourth solving means, the third in the solution, the lens array is constituted of a first lens array and the second lens array, the second in the lens array and the cylindrical convex lens and to a lens <br/> array with cylindrical convex lens array was integrated lens.

A fifth solving means is the method according to any one of the first to fourth solving means, wherein the reduction ratio of the light beam width by the beam reducing means in the short side direction is an aspect of the outer shape of the light modulating means. It is to be a ratio.

A sixth solving means is that in each of the first to fifth solving means, each lens cell forming the lens array has a square shape.

[0020]

The seventh solving means is the first solving means to the first solving means.
In any of the sixth solving means, that it has a polarization converting means in the optical path, spread only beam width corresponding to the long side direction of the pixels of the light modulation means between the light source and the beam reduction means is there.

An eighth solving means is the same as the seventh solving means, wherein the polarization conversion means makes the indefinite polarized lights orthogonal to each other.
It is composed of a polarization splitting means for splitting into one linearly polarized light, a light flux reflecting means for reflecting one polarized light split by the polarization splitting means, and a phase rotating means for rotating the polarization direction by 90 °.

A ninth solving means is the same as the eighth solving means, wherein the polarized light separating means is a polarizing beam splitter by a prism, the luminous flux reflecting means is a right-angled prism having an inclined surface as a reflecting surface, and the phase rotating means. Is a half-wave plate.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an image projection apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is an optical path diagram for explaining a main part of an illumination system that is an embodiment of an image projection apparatus according to the present invention. FIG. 1A shows a case where the apparatus is viewed from directly above. Of FIG. 1, that is, a horizontal optical path diagram, and FIG. 1B is a vertical optical path diagram. FIG. 2 is a perspective view showing an optical path for explaining an embodiment in which the polarization converting means 12 in FIG. 1 is constituted by a polarization beam splitter, a right-angle prism having a slanted surface as a reflecting surface, that is, a total reflection prism and a half-wave plate. 3 is a front view schematically showing the shape of the lens array 13 in FIG. 1, that is, a view seen from a direction along the optical axis.

In FIG. 1, reference numeral 11 is a light source section comprising a light source 11a using a metal halide lamp or the like, and a rotationally symmetrical reflecting mirror 11b having an opening in the light irradiation direction, and 12 is an indefinite state from the light source section 11. It is a polarization conversion means for aligning polarized light in a specific polarization direction, and an example of its configuration is shown in a perspective view in FIG. In FIG. 2, the polarization conversion means 1
Reference numeral 2 denotes a prismatic polarization beam splitter 12a which is a polarization splitting means and a total reflection prism 12 which is a light flux reflecting means.
b and a half-wavelength optical retardation plate which is a phase rotation means, that is, a half-wavelength plate 12c.

In FIG. 2, the polarization beam splitter 12 is shown.
Reference symbol a denotes a dielectric multilayer film deposited on one of the two right-angled prisms by vapor deposition, and the inclined faces are pasted together with a transparent adhesive. The incident light from the light source unit 11 has polarization directions orthogonal to each other. It is separated into two P-polarized waves and S-polarized waves. For example, the P-polarized wave is transmitted through the inclined surface and is emitted toward the lens array 13, and the other S-polarized wave is reflected at a right angle on the inclined surface and emitted toward the total reflection prism 12b. Here, the P-polarized wave is linearly polarized light that vibrates in the incident plane, and the S-polarized wave is linearly polarized light that vibrates in a plane orthogonal to the incident plane. The total reflection prism 12b is attached to the side surface of the polarization beam splitter 12a from which the S-polarized wave is reflected and emitted, and reflects the S-polarized wave at a right angle and emits it toward the lens array 13. Also, the half-wave plate 12c
Is attached to the emission side surface of the total reflection prism 12b,
The S-polarized wave emitted from the total reflection prism 12b is
It is rotated by a degree, converted into a P-polarized wave, and emitted. Therefore, the P-polarized wave that is the same as the P-polarized wave that has passed through the polarization beam splitter 12a is aligned and emitted to the lens array 13.

The half-wave plate 12c may be provided on the polarization beam splitter 12a side instead of the total reflection prism 12b side. In this case, the light emitted from the polarization conversion means 12 is S.
Aligned to polarized waves. In addition, the polarization beam splitter 12
The a and the total reflection prism 12b may be integrated by adhesion or may be made of integrated glass. In addition to the polarization beam splitter that uses the interference of the dielectric multilayer film, the polarized light separating means uses a glass material or a polymer material having optical anisotropy, or a diffraction grating such as a diffraction grating. It is also possible to use an application of the phenomenon.

Reference numeral 13 denotes a lens array for uniformly irradiating the entire surface of the liquid crystal panel 18 with the polarized light beam incident from the polarization conversion means 12 via the polarization beam splitter 12a and the half-wave plate 12c. Lens array 13a and second lens array 13b. First
As shown in FIG. 3, the lens array 13a of FIG. 3 has a large number of convex lenses each having a square aperture as two-dimensionally arranged as lens cells. The light is condensed in the vicinity of each corresponding lens cell of the second lens array 13b arranged in the same manner. In addition, each lens cell of the second lens array 13b has a distance of 1 near the focal length of each lens cell of the first lens array 13a.
A plurality of convex lenses arranged corresponding to pair 1, and a beam reducer for uniformly irradiating the entire surface of the liquid crystal panel 18 by superimposing the small light beams condensed by the first lens array 13a on each other. The light is emitted in the direction of 14.

Reference numeral 14 denotes a beam reducer, which has a cylindrical surface shape in the vertical direction as shown in the perspective view of FIG. 4, that is, a cylindrical convex lens 14a and a cylindrical concave lens 14b having a curvature in the short side direction of the pixel which is the horizontal direction. Are arranged in order. Cylindrical convex lens 14a
Is to reduce the parallel light emitted from each lens cell of the lens array 13 to, for example, 9/16 only in the short side direction of the pixels of the liquid crystal panel, that is, in the horizontal direction according to the aspect ratio of the screen of the liquid crystal panel 18. Then, the reduced emitted light is collimated by the cylindrical concave lens 14b and emitted toward the condenser lens 16.

Numeral 15 is a diaphragm which regulates a light beam which diffuses in the vertical direction, and is arranged at the focal position on the lens array side of the condenser lens, so that the illumination system becomes non-telecentric when the beam reducer 14 is inserted. It has a preventive function. Reference numeral 16 is a dichroic mirror 1 for incident light.
A condenser for focusing light on the liquid crystal panel 18 via 7.

The dichroic mirror 17 converts the incident light into R,
G, B is separated into each color light, and is composed of three mirrors, each of which selectively reflects only light in one of the R, G, and B wavelength bands and transmits other light. Have characteristics. The dichroic mirrors 17 are arranged at slightly different angles with respect to the incident optical axis so that the separated color lights are incident on the liquid crystal panel 18 at different incident angles. Reference numeral 18 denotes a light modulator, which is, for example, a microlens type liquid crystal panel that optically modulates the polarization direction of each incident color light for each pixel dot according to a color image signal and emits the light. Hereinafter, a case where the above-mentioned microlens type liquid crystal panel is used as the light modulating means will be described.

Each color light, which is modulated by the liquid crystal panel 18 for each pixel with respect to the incident color light, is detected by an emission side polarization plate (not shown) attached to the emission light side of the liquid crystal panel 18, An optical image, which is selectively transmitted and intensity-modulated for each pixel, is formed and arrives on the image screen by the projection lens to display a composite color image.

The operation of the image projection apparatus having the above-mentioned configuration will be described in more detail. In the present embodiment, the liquid crystal panel 18 as the light modulating means is a liquid crystal panel having a screen aspect ratio of 16: 9, similarly to the liquid crystal panel shown in the conventional example, and incident light to the liquid crystal panel 18, that is, illumination light. The ratio of the horizontal parallelism to the vertical parallelism corresponds to 1:
An example in which it is required to be 3 is shown. However, even if the aspect ratio of the screen of the liquid crystal panel 18 and the ratio of the horizontal parallelism and the vertical parallelism of the incident light are other than those described above,
It goes without saying that the idea of the present invention is applicable. Further, the light modulating means is not limited to the transmissive liquid crystal panel, but a reflective liquid crystal panel or the like may be used.

Further, in the present embodiment, the dichroic mirror 17 separates the light beams of R, G, and B, which are incident from different directions, into R, G, and B on the corresponding liquid crystal panel.
In order to collect light on each of the G and B pixels, a microlens array is provided on the surface of the liquid crystal panel in a one-to-one correspondence with a cell having one set of R, G, and B pixels. However, as the color light decomposing / condensing means, in addition to the present embodiment, a hologram or other means utilizing light diffraction or interference may be used.

The light beam generated by the light source section 11 is incident on the polarization conversion means 12. The incident light on the polarization conversion means 12 is converted to P by the polarization beam splitter 12a as described above.
The polarized wave and the S polarized wave are separated into two polarized components, and one polarized wave (P polarized wave in this embodiment) is transmitted through the polarized beam splitter 12a and emitted toward the lens array 13. The other polarized wave (in this embodiment, S
(Polarized wave) is reflected at a right angle by the polarization beam splitter 12a, and further, by the total reflection prism 12b, the half-wave plate 12c.
After being reflected in the direction, the half-wave plate 12c rotates the polarization direction by 90 degrees, converts it into a P-polarized wave, and emits it toward the lens array 13. As a result, the polarization direction is aligned with the P-polarized wave transmitted through the polarization beam splitter 12a, and at the same time, the width of the entire emitted light flux is longer than that of the incident light flux in the long side direction of the R, G, B pixels of the liquid crystal panel 18, that is, vertical. It can be spread about twice in the direction.

The light flux that has entered the first lens array 13a via the polarization conversion means 12 is the first lens array 1
Each lens cell 3a splits the light beam into a small light beam so that the entire screen of the liquid crystal panel 18 can be uniformly illuminated, and is focused on the corresponding lens cell of the second lens array 13b to form a secondary light source image. To be done. The corresponding lens cell of the second lens array 13b emits the condensed small luminous flux in the direction of the beam reducer 14 so that the entire surface of the liquid crystal panel is superposed and irradiated. Here, the lens array 13
Is a two-dimensional array of square-shaped convex lens cells as shown in FIG. 3, and since the secondary light source image is captured by the square-shaped lens cell, compared to the conventional rectangular-shaped lens cell. As a result, the light collection efficiency is improved, and the error sensitivity when the light axis of the light source lamp 11a of the light source unit 11 is deviated is kept at the same sensitivity level in both the horizontal and vertical directions. Because you can
It is possible to suppress the error sensitivity to an appropriate level.

The beam reducer 14 is composed of a cylindrical convex lens 14a and a cylindrical concave lens 14b arranged in order in the vertical direction, and when parallel light is incident, the beam widths of R, G, and B of the liquid crystal panel are changed. In the pixel, the short side direction, that is, only the horizontal direction is reduced to 9/16 according to the aspect ratio of the liquid crystal panel screen. FIG. 5 is a layout diagram showing the positional relationship between the lens system of the second lens array 13 b before and after the beam reducer 14 and the condenser lens 16. The position 15a at which the reduced image (virtual image) of the second lens array 13b is formed by the beam reducer 14 and the focal length of the condenser lens 16 are substantially aligned. At this time, the angular magnification of the beam reducer 14 is
It is the reciprocal of the reduction ratio of the beam width, which is 16/9 times as shown in FIG. Therefore, the second lens array 13b, the beam reducer 14, the condenser lens 16
In the lens group consisting of, the shape of the lens cell of the first lens array 13a is extended 16/9 times only in the horizontal direction to form a superimposed image, and the liquid crystal panel surface 18 having an aspect ratio of 16: 9 is uniformly illuminated. Is possible.

The parallelism of the illumination light incident on the liquid crystal panel surface is roughly determined by the outer shape of the lens array 13 and the magnification of the beam reducer 14. When a ratio of the horizontal parallelism to the vertical parallelism of the illumination light is required to be 1: 3, this parallelism ratio is the horizontal direction of the outer shape of the lens array 13 unless the beam reducer 14 is used. It is the ratio of the side length to the side length in the vertical direction, and the outer shape of the lens array 13 is a rectangle with a ratio of 1: 3. However, as shown in this embodiment, when the beam reducer 14 is inserted, the lens array 1 is increased by the magnification of the beam reducer 14, that is, 16/9 times.
The ratio of the side length in the horizontal direction to the side length in the vertical direction of the outer shape of No. 3 is compressed to a ratio of about 1: 2. Therefore,
As shown in FIG. 3, the outer shape of the lens array 13 in this embodiment can be closer to a square shape with a ratio of the length of the horizontal side to the length of the vertical side of 1: 2. As a result, even though the circular light flux is emitted from the light source unit 11, it is possible to reduce the light-condensing loss that occurs when the light flux in the short side direction of the first lens array 13a is blocked.

The cylindrical convex lens 14a of the beam reducer 14 may be integrally formed with the second lens array 13b to form a lens array 13c having a cylindrical convex shape as a whole, as shown in FIG. Further, the condenser lens 16 may be arranged not in a single lens, but in two groups, one in the vicinity of the lens array and the other in the vicinity of the liquid crystal panel.
Further, although the present embodiment shows an example in which the polarization conversion means 12 is arranged between the light source unit 11 and the lens array 13,
The same effect can be obtained by disposing the lens array 13 after the lens array 13. In addition, as shown in FIG.
Of the second lens array 13b 'by making the entire lens array 13a of the second lens array 13a a convex shape and the second lens array 13b a concave lens array 13b'. It is also possible to reduce the size of the system.

Further, as shown in FIG. 5, the beam reducer 1
In the vicinity of the position 15a where the reduced image (virtual image) of the second lens array 13b by 4 is formed, only the light flux diffused in the long side direction of the pixels of the liquid crystal panel 18, that is, the vertical direction is blocked, and the vertical light flux width is regulated. A diaphragm 15 is provided. The position of the diaphragm 15 is also matched with the focal position of the condenser lens 16 on the lens array side. Therefore, the parallelism of the illumination light incident on the liquid crystal panel 18 in the vertical direction is determined by the diaphragm 15, and at the same time, the diaphragm 1
The chief ray passing through the center of 5 becomes perfectly parallel light. On the other hand, regarding the parallelism in the horizontal direction, the second lens array 13b
Of the second lens array 13b, the focal point of the condenser lens is made to coincide with the image point 15a of the beam reducer 14 of the second lens array 13b, so that the principal ray in the horizontal direction is also perfectly parallel. Become light. Therefore, even though the optical system uses the beam reducer,
It is possible to realize a completely telecentric illumination system that can obtain a luminous flux that is parallel to the optical axis in both the horizontal and vertical directions, that is, parallel light, and it is possible to secure an optimal illumination state with significantly improved brightness over the entire LCD panel surface. .

[0041]

According to the present invention, both the outer shape of the lens array and the shape of each lens cell can be approximated to a square shape, so that the light collection efficiency in the lens array is improved and the brightness of the projected image is improved. Can be increased.

Further, uptake aspect ratio of the secondary light source images in the second lens array is 1: 1, and the error sensitivity when the optical axis shift or the like occurs in the light source lamp for any horizontal and vertical directions Can also be kept at the same level, so that the error sensitivity can be suppressed to an appropriate level.

[0043] Also, the horizontal direction, the fully telecentric illumination system obtained parallel light in the vertical direction both can be achieved, and efficient over the entire surface of the liquid crystal panel or light modulating means, it is possible to ensure optimal lighting conditions .

Further , the polarized light converting means can realize the polarized irradiation light suitable for illuminating the liquid crystal panel, and at the same time, the width of the emitted light beam can be widened in the long side direction of the pixels of the liquid crystal panel. It can be further improved.

[Brief description of drawings]

FIG. 1 is an optical path diagram for explaining a main part of an illumination system that is an embodiment of an image projection apparatus according to the present invention.

FIG. 2 is a perspective view for explaining an embodiment of the polarization conversion means in FIG.

FIG. 3 is a front view schematically showing the shape of the lens array in FIG.

4 is a perspective view of the beam reducer in FIG. 1. FIG.

5 is an arrangement diagram showing a positional relationship between a second lens array, a beam reducer, a diaphragm, and a condenser lens in FIG.

FIG. 6 is an optical path diagram showing another embodiment of the image projection apparatus according to the present invention.

FIG. 7 is an optical path diagram showing an embodiment in which the lens array portion of the image projection device according to the present invention is configured by a first convex lens-shaped lens array and a second concave lens-shaped lens array.

FIG. 8 is an optical path diagram showing an embodiment of an image projection device according to the prior art.

9 is a front view schematically showing the shape of the lens array in FIG.

FIG. 10 is a front view schematically showing a cell shape in which each of R, G, and B pixels of a liquid crystal panel, which is a light modulation element, constitutes one set.

[Explanation of symbols]

11, 41 ... Light source part, 12 ... Polarization conversion means, 12a ... Polarization beam splitter, 12b ... Total reflection prism, 12c
... Half-wave plate, 13, 43 ... Lens array, 13a, 43
a ... 1st lens array, 13a '... 1st convex lens shape lens array, 13b, 43b ... 2nd lens array, 13b' ... 2nd concave lens shape lens array, 13
c ... Second cylindrical convex lens shape lens array,
14 ... Beam reducer, 14a ... Cylindrical convex lens, 14b ... Cylindrical concave lens, 15 ... Aperture, 1
5a ... Condenser lens focal position, 16, 46 ... Condenser lens, 17, 47 ... Dichroic mirror, 1
8, 48 ... Liquid crystal panel.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI H04N 9/31 G02F 1/1335 530 (58) Fields investigated (Int.Cl. ⁷ , DB name) G03B 21/00-21 / 30 G02F 1/13 G02F 1/1335-1/13363 G02B 27/28 G03B 33/12

Claims (9)

(57) [Claims] 1. A plurality of image forming devices for irradiating light emitted from a light source.
Through a lens array having a lens cell, the light modulation means disposed pixels two-dimensionally controlling the transmitted light in response to image signals, and projecting the irradiation light from the light source, the image display In the image projection device to be performed, the pixel shape of the light modulation means is rectangular, and a beam reduction means for reducing the width of a light beam incident in the short side direction of the pixel, and the light modulation means.
Of the condenser lens to collect the irradiation light against
At the focal position on the lens array side, the image of the light modulator is displayed.
An image projection apparatus comprising: a diaphragm that blocks a light beam that diffuses in the long side direction of the element . 2. The image projection apparatus according to claim 1 , wherein the beam reduction means is provided in an optical path between the lens array and the light modulation means . 3. The image projecting device according to claim 1, wherein the beam reducing means is composed of a cylindrical convex lens and a cylindrical concave lens having a curvature in a short side direction of a pixel of the light modulating means. Projection device. The image projection apparatus according to claim 3, wherein the lens array is constituted of a first lens array and the second lens array, the second in the lens array and the cylindrical convex lens lens <br/> image projection apparatus characterized by a cylindrical convex lens array was integrated lens and array. 5. The image projection apparatus according to claim 1, wherein the reduction ratio of the light flux width by the beam reduction means in the short side direction is set as the aspect ratio of the outer shape of the light modulation means. Characteristic image projection device. 6. The image projecting device according to claim 1, wherein each lens cell forming the lens array has a square shape. 7. The image projection apparatus according to any of claims 1 to 6, in the optical path between the light source and the beam reduction means, corresponding to the long side direction of pixels of the light modulation means An image projection apparatus having a polarization conversion means for expanding only a light flux width. 8. The image projection apparatus according to claim 7 , wherein the polarization conversion means makes the indefinite polarized lights orthogonal to each other.
An image characterized by comprising a polarization splitting means for splitting into one linearly polarized light, a light flux reflecting means for reflecting one polarized light split by the polarization splitting means, and a phase rotation means for rotating the polarization direction by 90 °. Projection device. 9. The image projection apparatus according to claim 8 , wherein the polarization splitting means is a polarizing beam splitter by a prism, the light flux reflecting means is a right-angled prism having a slope as a reflecting surface, and the phase rotation means is An image projection apparatus, which is a half-wave plate.