JP2006058488A - Illumination optical device and projection type display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical device whose light quantity is very large and whose illuminance irregularity is small in using a light emitting element array such as an LED array as a light source, and to provide a projection type display device using the same. <P>SOLUTION: In the illumination optical device 10, the surface to be irradiated 30 being the incident surface of a liquid crystal panel 80 is irradiated with emitted light from the respective LEDs 21 of the LED array 20 through two microlens arrays 50 and 60 and a condenser lens 70. An LED array surface 22 and the principal surface of the microlens array 60 have nearly conjugate relation, and the principal surface of the microlens array 50 and the surface to be irradiated 30 have conjugate relation. The LED array surface 22 and the surface to be irradiated 30 do not have conjugate relation. By adopting an optical system where the LED array surface 22 and the surface to be irradiated 30 do not have conjugate relation, three design parameters on a light quantity transmission rate, the illuminance irregularity and the parallelism of illuminating light are easily optimized with good balance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an illumination optical device used for a liquid crystal projector and the like, and a projection display device using the same.

Projection display devices typified by liquid crystal projectors and projectors using minute pixel mirrors are rapidly spreading in connection with display of computer screens.
Conventionally, an illumination system of these projection type display devices generally uses a discharge lamp such as a high-pressure mercury lamp or a metal halide lamp as a light source.

  However, these discharge lamps require a high voltage power source and are large in size. In addition, since the heat generation is large, it is necessary to take heat dissipation means. Therefore, the projection type display device using these discharge lamps has a problem that the entire device becomes large.

  In addition, since these discharge lamps emit white light, in a projection display device, in order to perform color display, the light is split into three colors of red, green, and blue, and a light valve and a small pixel mirror are used for each color light. It is necessary to perform modulation by a light modulation device such as. Furthermore, since these discharge lamps generate not only the visible wavelength range to be used but also infrared light and ultraviolet light, it is necessary to use a filter for removing the infrared light and ultraviolet light. As described above, there is also a problem that the number of parts necessary for configuring the projection display device is large.

  In order to solve the problem of the illumination system using such a discharge lamp, in recent years, an illumination system using a light-emitting diode (LED), which is remarkably high in brightness and low in cost, has been proposed. An LED is originally a small electronic component and operates at a low voltage, so that the device can be significantly downsized. Further, when an LED is used as a light source, for example, as disclosed in Patent Document 1, red, green, and blue LEDs can be used, so that it is not necessary to split white light. However, the amount of light per LED is smaller than that of a discharge lamp. For this reason, it has been proposed to use a plurality of LEDs in an array (see, for example, Patent Document 2).

  Furthermore, since the LEDs can be switched on and off at a higher speed than the discharge lamp, each LED is controlled so that the three colors are sequentially lit, and the modulation by the light valve is performed in synchronization with this, Color display is possible. In such a configuration, it is not necessary to provide a light valve for each of the three color lights of red, green, and blue, and the projection display device can be further downsized.

Further, for example, Patent Document 3 discloses a planar light source including an LED array with a reflecting mirror in which LED chips are arranged on the center side of a concave mirror lens array.
Japanese Patent Laid-Open No. 10-269802 Japanese Patent Application Laid-Open No. 2002-244211 JP 2002-49326 A

  However, in the illumination system described in Patent Document 1 and the image projection apparatus described in Patent Document 2, the amount of light on a surface to be illuminated such as a light valve illuminated by light emitted from an LED is sufficient. In addition, there is a problem that the unevenness of illuminance on the irradiated surface is large.

  The reason why the amount of light on the illuminated surface is not sufficient is that the LED itself may still be insufficient in brightness, but the brightness of the LED is low because the illumination system is not adapted to the LED array light source. It is because it is not fully utilized.

Further, the reason why the uneven illuminance on the irradiated surface is large is that the variation in the amount of light between individual LEDs is unavoidable, and uneven illuminance tends to occur when a large number of LEDs are used.
The present invention has been made paying attention to such conventional problems, and its purpose is to provide an illumination optical device having a sufficiently large light amount and small illuminance unevenness when a light emitting element array such as an LED array is used as a light source. Another object is to provide a projection display device using the same.

  In order to solve the above problems, the invention according to claim 1 is a light emitting element array in which a plurality of light emitting elements are arranged in one plane, and a substantially rectangular shape that reflects light emitted from the plurality of light emitting elements. A concave mirror array having a plurality of concave mirrors that emit light toward an irradiated surface, and at least one microlens array and a condenser that are arranged between the light emitting element array and the irradiated surface and each have a plurality of microlens elements A light that is emitted from the plurality of light emitting elements and reflected by the concave mirror array is incident on the irradiated surface through the at least one microlens array and a condenser lens. The light emitting element array surface of the light emitting element array and the irradiated surface are not in a conjugate relationship.

  According to this, by adopting an optical system in which the light emitting element array surface and the irradiated surface are not in a conjugate relationship, it is easy to optimize the three design parameters in a balanced manner, such as the light amount transmission rate, illuminance unevenness, and the parallelism of illumination light. . Thereby, the illumination light quantity on an irradiated surface can be improved, and illuminance unevenness can also be reduced. Therefore, when the light emitting element is used as a light source, it is possible to realize an illumination optical device that has a sufficiently large light amount and small illuminance unevenness.

  The invention according to claim 2 is the illumination optical apparatus according to claim 1, wherein each light emitting element of the light emitting element array, each concave mirror of the concave mirror array, and each microlens element of the microlens array are 1 The gist is that they are arranged so as to face each other.

  According to this, the emitted light from each light emitting element can be effectively transmitted to the irradiated surface by each concave mirror and each microlens element. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

  According to a third aspect of the present invention, in the illumination optical device according to the second aspect, when each concave mirror of the concave mirror array is viewed from the optical axis direction of the condenser lens, the shape thereof is substantially the same as the rectangular shape of the irradiated surface. The gist is that they have a similar rectangular shape, and the concave mirrors are arranged in a plane perpendicular to the optical axis without any vertical and horizontal intervals.

  According to this, the emitted light from each light emitting element which is substantially a point light source can be made incident on each corresponding microlens element as a light beam having a rectangular cross section. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

  According to a fourth aspect of the present invention, in the illumination optical device according to the third aspect, when each microlens element of the microlens array is viewed from the optical axis direction of the condenser lens, the shape thereof is a rectangle of the irradiated surface. The gist of the present invention is that the microlens elements have a rectangular shape substantially similar to the shape, and are arranged in a plane perpendicular to the optical axis without any vertical and horizontal intervals.

  According to this, since the microlens array and the irradiated surface are in an imaging relationship, the shape when each microlens element is viewed from the optical axis direction is made to be a rectangular shape substantially similar to the rectangular shape of the irradiated surface. Thus, illumination light close to the shape of the irradiated surface can be formed by each microlens element, and light from each light emitting element can be used efficiently. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

  The invention according to claim 5 is the illumination optical device according to any one of claims 2 to 4, wherein each light emitting element, each concave mirror, and each The gist is that the microlens elements are arranged on the same axis.

  According to this, since each of a plurality of combinations (hereinafter referred to as segments) each composed of one light emitting element, one concave mirror, and one microlens element are arranged on the same axis, Light emitted from the light emitting element can be effectively transmitted to the irradiated surface.

  The invention according to claim 6 is the illumination optical device according to any one of claims 2 to 4, wherein each of the light emitting elements, each of the concave mirrors, and each of the light emitting elements arranged to face each other one to one. The gist of the invention is that the microlens elements are arranged so that there are a combination arranged coaxially with each other and a combination not arranged coaxially.

  According to this, after the light emitted from each light emitting element is reflected by the corresponding concave mirror, a part of the light beam traveling toward the irradiated surface hits the light emitting element itself, and the part becomes a shadow, and the irradiated surface It can suppress that it projects on the upper center vicinity. In other words, by making a combination having a coaxial shift in a part of a plurality of segments each composed of one light emitting element, one concave mirror, and one microlens element, the portion of the light emitting element itself can be changed. The influence of shadows can be averaged to suppress illuminance non-uniformity on the irradiated surface. Therefore, the illuminance unevenness on the irradiated surface can be improved.

  In addition, as a method for causing a combination with a shifted coaxiality, for example, it is desirable to slightly shift the coaxiality of each segment within one plane. Thereby, the illumination nonuniformity on a to-be-irradiated surface can be eliminated.

  The invention according to claim 7 is the illumination optical device according to claim 5 or 6, wherein at least one of the plurality of concave mirrors and part of the plurality of microlens elements has a different focal length or curvature from the others. The gist is to have a concave mirror or microlens element having a radius.

According to this, since a segment having a different light condensing position is present in a part of the plurality of segments, the illuminance unevenness on the irradiated surface can be improved.
In addition, as a method of causing a segment having a different light collection position to exist in some of the plurality of segments, it is desirable to slightly shift the light collection position of each segment. Therefore, it is possible to eliminate illuminance unevenness on the irradiated surface.

  The invention according to claim 8 is the illumination optical apparatus according to any one of claims 1 to 7, wherein the concave mirror array is a parabolic mirror array in which the concave mirror is a parabolic mirror, and the at least one The gist of the invention is to provide a pair of microlens arrays having the same arrangement of the microlens elements as a single microlens array.

According to this, the emitted light from each light emitting element that is substantially a point light source can be made incident on each corresponding microlens element as a light beam by each parabolic mirror, and the emitted light from each light emitting element is effectively covered. Can be transmitted to the irradiated surface. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

The invention according to claim 9 is the illumination optical apparatus according to claim 8, wherein the pair of microlens arrays are arranged apart from each other by a focal length.
According to this, the emitted light from each light emitting element can be effectively transmitted to the irradiated surface.

  According to a tenth aspect of the present invention, in the illumination optical device according to the ninth aspect, among the pair of microlens arrays, the one close to the light emitting element and the irradiated surface are arranged in a substantially conjugate relationship, The gist is that, in the pair of microlens arrays, the one far from the light emitting element and the surface of the light emitting element array are arranged in a substantially conjugate relationship.

  According to this, the emitted light from each light emitting element can be effectively transmitted to the irradiated surface, and the emitted light can be superimposed on the irradiated surface. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

  According to an eleventh aspect of the present invention, in the illumination optical device according to any one of the first to seventh aspects, the at least one microlens array is disposed in the vicinity of a front focal plane of the condenser lens. The microlens array is provided, and the irradiated surface is disposed in the vicinity of the rear focal plane of the condenser lens.

According to this, the emitted light from each light emitting element can be superimposed on the irradiated surface.
The invention according to claim 12 is the illumination optical apparatus according to claim 11, wherein the concave mirror array is an elliptical mirror array in which the concave mirror is an elliptical mirror.

  According to this, the emitted light from each light emitting element that is substantially a point light source can be incident on each corresponding microlens element as a light beam by each elliptical mirror, and the emitted light from each light emitting element can be effectively irradiated. Can be communicated to. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

  According to a thirteenth aspect of the present invention, in the illumination optical device according to the twelfth aspect, the light emitting element array is disposed in the vicinity of a first focal plane of the elliptical mirror array, and the microlens array is disposed in the elliptical mirror array. The main point is that it is arranged near the second focal plane.

According to this, the emitted light from each light emitting element can be effectively transmitted to the irradiated surface, and the light quantity transmission rate can be improved.
The invention according to claim 14 is the illumination optical device according to any one of claims 1 to 13, further comprising an incident-side end face and an exit-side end face between the condenser lens and the irradiated surface, and a quadrangular prism. The reflecting optical element having the inner surfaces of the four wall portions as reflecting surfaces is arranged such that the incident side end surface is positioned in the vicinity of the rear focal plane of the condenser lens and the emission side end surface is positioned in the vicinity of the irradiated surface. The gist of this is that

According to this, since the emitted light from each light emitting element is reflected by each reflecting surface of the reflective optical element and enters the irradiated surface, the illuminance non-uniformity on the irradiated surface can be further improved. .
The invention according to claim 15 is the illumination optical apparatus according to any one of claims 1 to 14, wherein the light emitting element array is a light emitting diode array including a plurality of light emitting diodes as the light emitting elements. The gist.

According to this, it is possible to realize an illumination optical device that uses a light emitting diode array as a light source and has a sufficiently large light amount and small illuminance unevenness.
According to a sixteenth aspect of the present invention, there is provided the illumination optical device according to any one of the first to fifteenth aspects, and a light modulation unit that is disposed at a position of the irradiated surface and modulates the light emitted from the illumination optical device. And a projection lens that projects the emitted light, which is light-modulated by the light-modulating means, onto a screen, a projection display device using an illumination optical device.

According to this, it is possible to realize a projection display device capable of high-quality display with high luminance and less luminance unevenness.
The invention according to claim 17 is the projection type display device using the illumination optical apparatus according to claim 16, wherein the light modulation means is a liquid crystal panel.

  According to this, it is possible to realize a liquid crystal projector capable of high-quality display with high luminance and little luminance unevenness.

  As described above, according to the present invention, when a light-emitting element array such as an LED array is used as a light source, an illumination optical device having a sufficiently large light amount and small illuminance unevenness and a projection display device using the same are realized. be able to.

  Embodiments of an illumination optical device embodying the present invention and an embodiment of a projection display device (liquid crystal projector) using the illumination optical device will be described below with reference to the drawings. In the description of each embodiment, similar parts are denoted by the same reference numerals, and redundant description is omitted.

  In general, the goal of the illumination system design of the illumination optical device is to optimize three of the light amount transmission rate, the illuminance unevenness, and the parallelism of the illumination system. Usually, it is conceivable to base an optical system in which the LED array surface and the irradiated surface are in a conjugate relationship. However, in the case of an optical system that is “conjugated”, in order to improve the parallelism of the illumination system, it is difficult to achieve the target value of the illumination system design other than reducing each LED of the LED array. is there. Therefore, in each of the following embodiments according to the present invention, by using an optical system “the LED array surface and the irradiated surface are not in a conjugate relationship”, three designs of light amount transmission rate, illuminance unevenness, and parallelism of the illumination system are used. It is characterized by easy optimization of parameters.

[First embodiment]
The illumination optical apparatus according to the first embodiment will be described with reference to FIGS.
1 is a plan view showing a schematic configuration of an illumination optical apparatus according to the first embodiment, FIG. 2 is a longitudinal sectional view of a microlens array, FIG. 3 is a front view showing the arrangement of the microlens array, FIG. 4 is a perspective view showing one parabolic mirror.

  The illumination optical device 10 according to the first embodiment shown in FIG. 1 is a liquid crystal projector as a projection display device including a liquid crystal panel (light valve) as a light modulation device that modulates irradiated light based on image data. Used for.

  As shown in FIG. 1, the illumination optical device 10 includes an LED array 20 with a parabolic mirror array, and two microlens arrays 50 and 60 arranged between the LED array 20 and the irradiated surface 30. And a condenser lens 70.

Further, the illumination optical device 10 irradiates the liquid crystal panel 80 with the emitted light from each LED 21 of the LED array 20 via the two (a pair of) microlens arrays 50 and 60 and the condenser lens 70. ing. The LED array 20 corresponds to a light emitting element array having a plurality of LEDs 21 as light emitting elements. Further, the incident surface of the liquid crystal panel 80 is L
The irradiated surface 30 is irradiated with light emitted from the ED 21.

  As shown in FIGS. 1 to 3, the LED array 20 with a parabolic mirror array includes an LED array 20 having a plurality of LEDs 21 arranged two-dimensionally and a plurality of parabolic mirrors arranged two-dimensionally. A parabolic mirror array 40 having 41 is integrated. In the LED array 20 with the parabolic mirror array, the LED array 20 and the parabolic mirror array are arranged such that each of the plurality of LEDs 21 is located in the vicinity of each focal position of the plurality of parabolic mirrors 41. 40 is integrated. The parabolic mirror array 40 corresponds to a concave mirror array having a plurality of parabolic mirrors 41 as concave mirrors.

  As a result, the light emitted from each LED 21 that is substantially a point light source is reflected by each parabolic mirror 41 so as to be incident on each microlens element 51 of the microlens array 50 as a parallel light flux from the LED array surface 22. It has become. Here, the “LED array surface 22” is a surface constituted by the light emitting surfaces of the chips of the plurality of LEDs 21 arranged two-dimensionally in one plane.

  In this example, the LED array 20 with a parabolic mirror array is configured by combining one LED 21 and one parabolic mirror 41, as shown in FIGS. 2 and 3, and the surface is a sapphire substrate. 42 for protection. Each chip of the plurality of LEDs 21 is bonded to a sapphire substrate 42, and an electrode on each chip and a wiring pattern formed on the sapphire substrate 42 are connected by wire bonding. 1 and 3, the sapphire substrate 42 is not shown.

  Two microlens arrays 50 and 60 having the same focal length f1 were used. In FIG. 1, D1b = f1 and D2 = D3 = f2. f2 is the focal length of the condenser lens 70.

  As shown in the following specifications (Example 1), D1b = 6.8 mm and D2 = D3 = 32.4 mm. Further, D1a = 10 mm. Here, D1a is the distance between the microlens array 50 and the top of each parabolic mirror 41 of the parabolic mirror array 40.

  In the illumination optical device 10 arranged in this way, the LED array surface 22 of the LED array 20 and the main surface of the microlens array 60 are substantially conjugated, and the main surface of the microlens array 50 and the irradiated surface 30 are conjugated. It has become. However, the illumination optical device 10 is characterized in that the LED array surface 22 and the irradiated surface 30 are not in a conjugate relationship.

In the illumination optical device 10, the LEDs 21, the parabolic mirrors 41, and the microlens elements 51 and 61 are arranged so as to face each other one to one.
In the illumination optical device 10, when each paraboloid mirror 41 of the parabolic mirror array 40 is viewed from the optical axis direction of the condenser lens 70, the shape thereof is a rectangular shape that is substantially similar to the rectangular shape of the irradiated surface 30. It is. That is, each parabolic mirror 41 has four arc-shaped edges 41 a, 41 b, 41 c and 41 d (see FIGS. 3 and 4), and these four edges are taken from the optical axis direction of the condenser lens 70. The shape when viewed is a rectangular shape as indicated by the solid line in FIG. 3 and the broken line in FIG. Further, in the illumination optical device 10, the microlens elements 51 and 61 are arranged in a single plane perpendicular to the optical axis without any vertical and horizontal intervals.

  Further, in the illumination optical device 10, the plurality of LEDs 21 of the LED array 20 have a single chip position of each LED 21 and the center of each parabolic mirror 41 (intersection of rectangular diagonal lines) as shown in FIG. It is desirable to provide an LED 21 that does not.

  In general, in an LED array with a concave mirror, after the light emission of the LED is reflected by the concave mirror, a part of the light beam (reflected light) that travels forward strikes the LED chip itself, and that part becomes a shadow, which is irradiated. It may be projected near the center on the surface.

  In order to weaken the influence of the shadow of the LED itself and improve the illuminance uniformity, in the illumination optical device 10 of this example, in each segment of the LED array 20 with a parabolic mirror array, The centers of the LED 21 and the parabolic mirror 41 are shifted little by little as shown in FIG.

  In the illumination optical device 10, the microlens arrays 50 and 60 include a pair of microlens arrays in which the arrangement of the microlens elements 51 and 61 is the same as the arrangement of the parabolic mirrors 41 of the parabolic mirror array 40. And spaced apart from each other by the focal length f1.

According to 1st Embodiment comprised as mentioned above, there exist the following effects.
The LED array surface 22 and the irradiated surface 30 (liquid crystal panel 80) are not conjugated. In this way, by adopting an optical system in which the LED array surface 22 as the light emitting element array surface and the irradiated surface 30 are not in a conjugate relationship, three design parameters of light quantity transmission rate, illuminance unevenness, and parallelism of illumination light. It is easy to optimize the balance. Thereby, the illumination light quantity on the to-be-irradiated surface 30 can be improved, and illumination nonuniformity can also be made small. Therefore, when the LED array 20 is used as a light source, the illumination optical device 10 having a sufficiently large light amount and small illuminance unevenness can be realized.

  Each LED 21, each parabolic mirror 41, and each microlens element 51, 61 are arranged so as to face each other one-to-one, and thus each parabolic mirror 41 and each microlens element 51. 61, the light emitted from each LED 21 can be effectively transmitted to the irradiated surface 30. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface 30 can be increased.

  When each parabolic mirror 41 of the parabolic mirror array 40 is viewed from the optical axis direction of the condenser lens 70, the shape thereof is substantially similar to the rectangular shape of the irradiated surface 30, and each parabolic mirror 41 The object mirrors 41 are arranged in a single plane perpendicular to the optical axis without being spaced vertically and horizontally. For this reason, the emitted light from each LED 21 which is a substantially point light source can be made incident on the corresponding microlens elements 51 and 61 as a light beam having a rectangular cross section. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

On the other hand, when the shape of each parabolic mirror 41 is not a rectangular shape as in this example, for example, a circular shape, the irradiation light amount on the irradiated surface 30 is about 10 to 20% as compared with the rectangular shape. Decrease.
When the microlens elements 51 and 61 of the microlens arrays 50 and 60 are viewed from the optical axis direction of the condenser lens 70, the shape thereof is a rectangular shape substantially similar to the rectangular shape of the irradiated surface 30, and each The microlens elements 51 and 61 are arranged in a plane perpendicular to the optical axis without any vertical and horizontal intervals. Since the microlens arrays 50 and 60 and the irradiated surface 30 are in an imaging relationship, the shape of the microlens elements 51 and 61 viewed from the optical axis direction is a rectangular shape that is substantially similar to the rectangular shape of the irradiated surface 30. Thus, illumination light close to the shape of the irradiated surface 30 can be formed by the microlens elements 51 and 61, and light from each LED 21 can be used efficiently. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface 30 can be increased.

Each LED 21, each parabolic mirror 41, and each microlens element 51, 61 are arranged substantially coaxially. As a result, each of the plurality of segments each composed of one LED 21, one parabolic mirror 41, and one microlens element 51, 61 is arranged on the same axis. The emitted light can be effectively transmitted to the irradiated surface 30.

  ○ A combination (segment) in which each LED 21, each parabolic mirror 41, and each microlens element 51, 61 arranged so as to face each other in one-to-one correspondence are arranged coaxially with each other. Arrangements are made so that there are combinations (segments) that have not been made. Thereby, after the emitted light from each LED 21 is reflected by the corresponding parabolic mirror 41, a part of the light beam traveling toward the irradiated surface 30 hits the chip itself of the LED 21, and the part becomes a shadow, Projection to the vicinity of the center on the irradiated surface 30 can be suppressed. In other words, by having a combination of coaxial shifts in a part of a plurality of segments each composed of one LED 21, one parabolic mirror 41, and one microlens element 51, 61, By averaging the influence of the LED 21 chip itself being shaded, it is possible to suppress illuminance non-uniformity on the irradiated surface 30. Therefore, illuminance unevenness on the irradiated surface 30 can be improved.

In particular, in this example, as shown in FIG. 3, the coaxiality of each segment is shifted little by little within one plane, so that uneven illuminance on the irradiated surface can be eliminated.
The microlens arrays 50 and 60 are a pair of microlens arrays in which the arrangement of the microlens elements 51 and 61 is the same as the arrangement of the parabolic mirrors 41 of the parabolic mirror array 40, and the focal lengths f1 of each other. Are only spaced apart. Thereby, the emitted light from each LED 21 that is a substantially point light source can be made incident on each corresponding microlens element 51, 61 as a parallel light beam by each parabolic mirror 41, and the emitted light from each LED 21 can be effectively used. It can be transmitted to the irradiated surface 30. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface can be increased.

  Of the pair of microlens arrays 50 and 60, the one closer to the LED array 20 (microlens array 50) and the irradiated surface 30 are arranged so as to be substantially conjugate, and the one far from the LED array 20 The (microlens array 60) and the LED array surface 22 are arranged so as to be substantially conjugate. Thereby, the emitted light from each LED 21 can be effectively transmitted to the irradiated surface 30, and the emitted light can be superimposed on the irradiated surface 30. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface 30 can be increased.

  The micro lens array 60 is disposed near the front focal plane of the condenser lens 70, and the liquid crystal panel 80 (irradiated surface 30) is disposed near the rear focal plane of the condenser lens 70. Thereby, the emitted light from each LED 21 can be superimposed on the irradiated surface 30.

Example 1
The specifications of each optical component used in the illumination optical apparatus 10 according to the first embodiment are as follows.

<LED array 20>
The following three types of LEDs (red LED, green LED, blue LED) were used for the LED 21 of the LED array 20.

Red LED;
・ Wavelength 625nm
・ Chip dimensions 0.3mm × 0.3mm
・ Total light quantity per chip 44 (lm)
・ Number 18
Green LED;
・ Wavelength 530nm
・ Chip dimensions 0.3mm × 0.3mm
-Total light intensity per chip 30 (lm)
・ Number 62
Blue LED;
・ Wavelength 460nm
・ Chip dimensions 0.3mm × 0.3mm
・ Total light intensity per chip: 10 (lm)
・ Number 37
<Parabolic mirror array 40>
The specification of the parabolic mirror array 40 is as follows.

-Parabolic mirror 41 with a focal length of 0.75mm
・ Pitch width 4mm, length 3mm
-9 horizontal array x 13 vertical array-Overall dimensions 36 mm x 39 mm
-The shape of one pixel is a rectangular shape of 4 mm x 3 mm, and is arranged without leaving a gap vertically and horizontally.

・ Structure ・ Pressed glass using a mold.
A reflective film of a dielectric multilayer film is formed on the surface of the parabolic mirror 41.

<LED array 20 overall>
・ Arrangement pitch 4mm wide, 3mm long
-Number of length and width 9 width, 13 height-Each LED 21 is bonded to a sapphire substrate 42 (see FIG. 2). The electrode on each LED 21 chip and the wiring pattern (formed with a transparent conductive film) formed on the sapphire substrate 42 are connected by wire bonding.

-It is set as the LED array integrated with the parabolic mirror array 40 so that LED21 and the parabolic mirror 41 may become 1: 1.
Each paraboloid mirror (each segment) 41 of the parabolic mirror array 40 has a rectangular shape substantially similar to the irradiated surface 30 (see FIG. 3). Moreover, the chip | tip of each LED21 was shifted and arrange | positioned from the centerline of each parabolic mirror 41. FIG. This has an effect of reducing illuminance unevenness.

<Microlens arrays 50 and 60>
The specifications of the microlens elements 51 and 61 of the microlens arrays 50 and 60 are as follows.

・ Focal distance f1 = 6.8mm
・ Pitch width 4mm, length 3mm
-9 horizontal array x 13 vertical array-Overall dimensions 36 mm x 39 mm
-1 pixel shape 4mm x 3mm
-Structure-It is injection-molded using a mold, and the pitch of each microlens array 50, 60 is matched with the pitch of the LED array 20, and each microlens element 51, 61 and each LED 21 correspond one-to-one. The configuration.

<Condenser lens 70>
・ Focal distance f2 = 32.4 mm
・ Dimension 50.3mm
<Irradiated surface 30>
・ LCD panel 80
・ Dimensions 14.7 x 10.7mm (0.7 inch diagonal)
<Evaluation result of Example 1>
In the illumination optical device 10 of Example 1 having the above specifications, each LED 21 was driven at 350 mA (power consumption 143 W) to emit light with the entire LED array 20 having a light quantity of 3022 (lm). At this time, about 1500 (lm) of light entered the liquid crystal panel 80 (14.7 × 10.7 mm). That is, the light quantity transmission rate is about 50%, which is an improvement over the conventional liquid crystal projector optical system of about 15%. In addition, it can be said that the characteristics are equal to or better than those of a minute pixel mirror type optical system. Further, the illuminance unevenness in the surface (in the irradiated surface 30) at that time was about 30%.

[Second Embodiment]
An illumination optical apparatus according to the second embodiment will be described with reference to FIG.
As shown in FIG. 5, the illumination optical device 10A includes an LED array 20A with an elliptical mirror array, a single microlens array 60A disposed between the LED array 20A and the irradiated surface 30, and a condenser. A lens 70.

  The illumination optical device 10A is configured to irradiate the liquid crystal panel 80 with the emitted light from each LED 21 of the LED array 20A via the micro lens array 60A and the condenser lens 70.

  The LED array 20A with an elliptical mirror array includes an LED array 20A having a plurality of LEDs 21 arranged two-dimensionally in the same manner as the LED array 20, and a plurality of LEDs arranged two-dimensionally like the parabolic mirror array 40. The elliptical mirror array 40A having the elliptical mirror 41A is integrated. In the LED array 20A with an elliptical mirror array, the LED array 20A and the elliptical mirror array 40A are integrated so that each LED 21 is positioned in the vicinity of the first focal position of each elliptical mirror 41A. . As a result, the light emitted from each LED 21 that is substantially a point light source is reflected by each elliptical mirror 41A so as to be condensed from the LED array surface 22 and incident on each microlens element 61A of the microlens array 60A. It has become.

  The microlens array 60A is disposed in the vicinity of the second focal plane formed by the second focal position of each elliptical mirror 41A. That is, the microlens array 60A is arranged such that the center of each microlens element 61A is positioned in the vicinity of the second focal point of each corresponding elliptical mirror 41A. The microlens array 60 </ b> A is disposed near the front focal plane of the condenser lens 70.

  Here, D1 = f1 and D2 = D3 = f2. f2 is the focal length of the condenser lens 70. f1 is the focal length of the microlens array 60A, and f2 is the focal length of the condenser lens 70. D1 is the distance between the microlens array 60A and the top of each elliptical mirror 41A of the elliptical mirror array 40A.

In the illumination optical device 10A arranged in this way, the LED array surface 22A of the LED array 20A and the main surface of the microlens array 60A have a substantially conjugate relationship, and the surface (elliptical reflection) of each elliptical mirror 41A of the elliptical mirror array 40A. Surface) and the irradiated surface 30 are in a conjugate relationship. However, the illumination optical device 10A is characterized in that the LED array surface 22A and the irradiated surface 30 are not in a conjugate relationship.

According to 2nd Embodiment comprised as mentioned above, in addition to the effect which the said 1st Embodiment show | plays, there exist the following effects.
As a microlens array, one microlens array 60 </ b> A disposed near the front focal plane of the condenser lens 70 is provided, and the irradiated surface 30 is disposed near the rear focal plane of the condenser lens 70. Thereby, the emitted light from each LED 21 can be superimposed on the irradiated surface 30.

  In the LED array 20A with an elliptical mirror array, the LED array 20A and the elliptical mirror array 40A are integrated so that each LED 21 is positioned in the vicinity of the first focal position of each elliptical mirror 41A. . For this reason, light emitted from each LED 21 that is substantially a point light source can be made incident on each corresponding microlens element 61A as a condensed light beam by each elliptical mirror 41A, and the light emitted from each LED 21 can be effectively irradiated. 30. Therefore, the light quantity transmission rate can be improved, and the light quantity on the irradiated surface 30 can be increased.

  The microlens array 60A is disposed in the vicinity of the second focal plane formed by the second focal position of each elliptical mirror 41A, so that the emitted light from each LED 21 is effectively transmitted to the irradiated surface 30. The light quantity transmission rate can be improved.

(Example 2)
The specifications of each optical component used in the illumination optical apparatus 10A according to the first embodiment are as follows.

<LED array 20A>
The specification of each LED 21 of the LED array 20A is the same as that of each LED of the LED array 20 of the first embodiment.

<Oval mirror array 40A>
The specification of the elliptical mirror array 40A is as follows.
-Elliptical mirror 41A with a focal length of 6.8mm
・ Pitch width 4mm, length 3mm
-9 horizontal array x 13 vertical array-Overall dimensions 36 mm x 39 mm
-The shape of one pixel is a rectangular shape of 4 mm x 3 mm, and is arranged without leaving a gap vertically and horizontally.

・ Structure ・ Pressed glass using a mold.
A dielectric multilayer reflective film is formed on the surface of the elliptical mirror 41A.

<Whole LED array 20A>
The specification of the entire LED array 20A is the same as that of the LED array 20 of the first embodiment.

<Microlens array 60A>
The specification of each microlens element 61A of the microlens array 60A is the same as that of each microlens element 61A of the microlens array 60 of the first embodiment.

<Condenser lens 70>
The specification of the condenser lens 70 is the same as that of the condenser lens 70 of the first embodiment.
<Irradiated surface 30>
The irradiated surface 30 uses a liquid crystal panel 80 having the same specifications as in the first embodiment.

<Evaluation results of Example 2>
In the illumination optical device 10A of Example 2 having the above specifications, each LED 21 was driven at 350 mA (power consumption 143 W) to emit light with the entire LED array 20A being 3022 (lm). At this time, about 1500 (lm) of light entered the liquid crystal panel 80 (14.7 × 10.7 mm). That is, the light quantity transmission rate is about 50%, which is an improvement over the conventional liquid crystal projector optical system of about 15%. In addition, it can be said that the characteristics are equal to or better than those of a minute pixel mirror type optical system. Further, the illuminance unevenness in the surface (in the irradiated surface 30) at that time was about 30%.

[Third embodiment]
An illumination optical apparatus according to the third embodiment will be described with reference to FIG.
As shown in FIG. 6, the illumination optical apparatus 10B includes an incident side end surface 90a and an emission side end surface 90b between the condenser lens 70 and the irradiated surface 30 in the second embodiment shown in FIG. A reflective optical element 90 is disposed in which the inner surfaces of the four wall portions of the prism are the reflective surfaces. The reflection optical element 90 is disposed such that the incident side end surface 90 a is positioned in the vicinity of the rear focal plane of the condenser lens 70 and the emission side end surface 90 b is positioned in the vicinity of the irradiated surface 30.

According to 3rd Embodiment comprised as mentioned above, in addition to the effect which the said 2nd Embodiment show | plays, there exist the following effects.
O The emitted light from each LED 21 is reflected by each reflecting surface inside the reflective optical element 90 and enters the irradiated surface 30, so that the illuminance non-uniformity on the irradiated surface 30 can be further improved.

(One Embodiment of Liquid Crystal Projector)
Next, an embodiment of a liquid crystal projector as a projection display device using an illumination optical device will be described with reference to FIG.

  The liquid crystal projector includes the illumination optical device 10 according to the first embodiment shown in FIG. 1 and a liquid crystal panel as a light modulation unit that is disposed at the position of the irradiated surface 30 and modulates light emitted from the illumination optical device 10. (Light valve) 80 and a projection lens 100 that projects the emitted light light-modulated by the liquid crystal panel 80 onto the screen 110.

As the LED 21 of the LED array 20 of the liquid crystal projector, for example, three types of LEDs (red LED, green LED, blue LED) are used as in the first embodiment.
In this liquid crystal projector, each LED 21 is controlled so that three types of LEDs are sequentially turned on, and the liquid crystal panel 80 is driven based on the image data for each color in synchronization with each LED being turned on sequentially. Images are sequentially formed, and light representing the images is projected onto the screen 110 by the projection lens 100. As a result, full-color images are sequentially displayed on the screen 110.

According to one embodiment of the liquid crystal projector configured as described above, a liquid crystal projector capable of high-quality display with high luminance and less luminance unevenness can be realized.
In addition, this invention can also be changed and embodied as follows.

In the first embodiment, not only the positional relationship between each LED 21 and each parabolic mirror 41, but also the positional relationship between each LED 21 and each microlens element 51, 61 of the microlens arrays 50, 60 may be shifted. That is, it is desirable that there is a segment in which at least one of the LED array 20, the parabolic mirror array 40, and the microlens arrays 50 and 60 is not arranged on the same axis. As a result, a segment having a different light condensing position is present in a part of the plurality of segments, so that unevenness in illuminance on the irradiated surface can be improved.

  In the first embodiment, among the plurality of parabolic mirrors 41, the parabolic mirrors 41 having different focal lengths may be arranged in part. Also in this case, similarly to the above, the influence of the shadow of the LED 21 itself can be weakened, and illuminance unevenness on the irradiated surface can be improved.

  In the first embodiment, portions having different focal lengths or curvature radii of the microlens elements 51 and 61 may be combined. As a result, a segment having a different light condensing position is present in a part of the plurality of segments, so that unevenness in illuminance on the irradiated surface can be improved.

  In the third embodiment, the configuration in which the reflective optical element 90 is arranged in the illumination optical apparatus 10A according to the second embodiment shown in FIG. 5 has been described as an example. However, according to the first embodiment shown in FIG. The present invention can also be applied to a configuration in which the reflective optical element 90 is disposed in the illumination optical device 10.

  In each of the above embodiments, the configuration using the LED arrays 20 and 20A having a plurality of LEDs (light emitting diodes) 21 as a light emitting element array including a plurality of light emitting elements has been described as an example. The present invention is also applicable to a light emitting element array including a plurality of point light sources.

  In each of the above embodiments, the configuration in which the incident surface of the liquid crystal panel 80 serving as the light modulation unit is the irradiated surface 30 irradiated with the light emitted from each LED 21 has been described as an example. The present invention can also be applied to a projection display device using light modulation means other than a light valve. For example, the present invention is also applicable to a configuration in which a projection display device is configured by a micro-pixel mirror reflection deflection type image display device using a digital mirror device as a light modulation means, and the reflection surface of each micro-pixel mirror is an irradiated surface 30. Is applicable.

1 is a plan view showing a schematic configuration of an illumination optical apparatus according to a first embodiment. The longitudinal cross-sectional view of the micro lens array with a parabolic mirror. The front view which shows arrangement | positioning of each LED and each parabolic mirror in the microlens array. The perspective view which shows one parabolic mirror. The top view which shows schematic structure of the illumination optical apparatus which concerns on 2nd Embodiment. The top view which shows schematic structure of the illumination optical apparatus which concerns on 3rd Embodiment. The top view which shows the liquid crystal projector comprised using the illumination optical apparatus shown in FIG.

Explanation of symbols

  f1 ... focal length 10,10A, 10B ... illumination optical device 20,20A ... LED array, 22,22A ... LED array surface, 30 ... irradiated surface, 40 ... parabolic mirror array, 40A ... elliptic mirror array, DESCRIPTION OF SYMBOLS 41 ... Parabolic mirror, 41A ... Ellipse mirror, 50, 60, 60A ... Micro lens array, 51, 61, 61A ... Micro lens element, 70 ... Condenser lens, 80 ... Liquid crystal panel, 90 ... Reflective optical element, 90a ... Incident side end face, 90b... Exit side end face, 100... Projection lens, 110.

Claims (17)

A light-emitting element array in which a plurality of light-emitting elements are arranged in one plane; and a concave mirror array having a plurality of concave mirrors that reflect emitted light from the plurality of light-emitting elements and emit the light toward a substantially rectangular shaped irradiated surface; An at least one microlens array and a condenser lens each disposed between the light emitting element array and the irradiated surface, each having a plurality of microlens elements,
The light emitted from the plurality of light emitting elements and reflected by the concave mirror array is configured to enter the irradiated surface via the at least one microlens array and a condenser lens, and the light emitting element An illumination optical apparatus, wherein the light emitting element array surface of the array and the irradiated surface are not in a conjugate relationship. The illumination optical apparatus according to claim 1,
The illumination optical device, wherein each light emitting element of the light emitting element array, each concave mirror of the concave mirror array, and each microlens element of the microlens array are arranged so as to be opposed to each other one to one. . The illumination optical apparatus according to claim 2,
When each concave mirror of the concave mirror array is viewed from the optical axis direction of the condenser lens, the shape thereof is a rectangular shape substantially similar to the rectangular shape of the irradiated surface, and each concave mirror is perpendicular to the optical axis. 1. An illumination optical apparatus, wherein the illumination optical apparatus is arranged in a single plane with no vertical and horizontal intervals. The illumination optical apparatus according to claim 3.
When each microlens element of the microlens array is viewed from the optical axis direction of the condenser lens, the shape is a rectangular shape substantially similar to the rectangular shape of the irradiated surface, and each microlens element is the An illumination optical device, wherein the illumination optical device is arranged in a plane perpendicular to the optical axis without being spaced apart vertically and horizontally. The illumination optical apparatus according to any one of claims 2 to 4,
The illumination optical device characterized in that the light emitting elements, the concave mirrors, and the microlens elements arranged so as to face each other one to one are arranged coaxially. The illumination optical apparatus according to any one of claims 2 to 4,
There are combinations in which the light-emitting elements, the concave mirrors, and the microlens elements arranged so as to face each other in a one-to-one relationship are arranged coaxially with each other and combinations that are not arranged coaxially. An illumination optical device characterized by being arranged to do so. The illumination optical apparatus according to claim 5 or 6,
An illumination optical apparatus, wherein a concave mirror or a microlens element having a focal length or a radius of curvature different from the other is present in at least one of a part of the plurality of concave mirrors and a part of the plurality of microlens elements. In the illumination optical device according to any one of claims 1 to 7,
The concave mirror array is a parabolic mirror array in which the concave mirror is a parabolic mirror, and the at least one microlens array includes a pair of microlens arrays having the same arrangement of the microlens elements. An illumination optical device. The illumination optical apparatus according to claim 8, wherein
The pair of microlens arrays are arranged to be spaced apart from each other by a focal length. The illumination optical apparatus according to claim 9, wherein
Of the pair of microlens arrays, the one close to the light emitting element and the irradiated surface are arranged so as to be substantially conjugate,
An illumination optical apparatus comprising: a pair of microlens arrays arranged so that a side farther from the light emitting element and the light emitting element array surface are in a conjugate relationship. In the illumination optical device according to any one of claims 1 to 7,
The at least one microlens array includes one microlens array disposed near the front focal plane of the condenser lens, and the irradiated surface is disposed near the rear focal plane of the condenser lens. An illumination optical device. The illumination optical apparatus according to claim 11.
2. The illumination optical apparatus according to claim 1, wherein the concave mirror array is an elliptical mirror array in which the concave mirror is an elliptical mirror. The illumination optical apparatus according to claim 12,
An illumination optical apparatus, wherein the light emitting element array is disposed in the vicinity of a first focal plane of the elliptical mirror array, and the microlens array is disposed in the vicinity of a second focal plane of the elliptical mirror array. The illumination optical apparatus according to any one of claims 1 to 13,
A reflective optical element having an incident-side end surface and an exit-side end surface between the condenser lens and the irradiated surface and having the inner surfaces of the four wall portions of the quadrangular prism as reflecting surfaces, the incident-side end surface being the condenser lens An illumination optical apparatus, wherein the illumination optical apparatus is disposed in the vicinity of the rear focal plane and so that the exit-side end surface is positioned in the vicinity of the irradiated surface. The illumination optical apparatus according to any one of claims 1 to 14,
2. The illumination optical apparatus according to claim 1, wherein the light emitting element array is a light emitting diode array including a plurality of light emitting diodes as the light emitting elements. An illumination optical device according to any one of claims 1 to 15, a light modulation means that is disposed at a position of the irradiated surface and modulates light emitted from the illumination optical device, and light is emitted by the light modulation means. A projection display device using an illumination optical device, comprising: a projection lens that projects the modulated emitted light onto a screen. In the projection type display apparatus using the illumination optical apparatus according to claim 16,
A projection display apparatus using an illumination optical apparatus, wherein the light modulation means is a liquid crystal panel.

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