JP2007047335A - Illuminator, optical modulation device and projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator which is miniaturized and thinned, and an optical modulation device and a projection type display device which are equipped with the illuminator. <P>SOLUTION: The illuminator is equipped with: a light emitting element array 1 having non-uniform light distribution characteristic; a coupling lens 2 arranged corresponding to each of the respective light emitting elements of the light emitting element array 1; a first lens array 3; a second lens array 4; and a surface to be illuminated 5. An optical device 6 for reducing uneven light quantity distribution of the surface to be illuminated 5 caused by the light distribution characteristic of the light emitting element is arranged between the coupling lens 2 and the first lens array 3 or near the coupling lens 2 and the first lens array 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination device capable of efficiently condensing and illuminating light from an array light source having a light distribution characteristic in a predetermined range with little unevenness, a light modulation device including the illumination device, and a projection type The present invention relates to a display device.

In a conventional digital projector or the like, a white light lamp such as a high-pressure mercury lamp, a xenon lamp, or a metal halide lamp is used as a light source. A common disadvantage of these lamps is that they involve a large amount of infrared or heat radiation.
Further, in the color separation / combination of the dichroic mirror / prism, it is difficult to balance the light amounts of the three primary colors and there is a limit in color reproducibility, and the size is increased and the number of parts is increased.
Many inventions using LEDs, LDs, etc. as substitutes for conventional illumination light sources have been filed, but few can solve the light amount distribution on the illuminated surface due to the non-uniform light distribution characteristics of these light sources.
For example, in Patent Document 1, a light source, a lens corresponding to the light source, a microlens array, a condenser lens, two microlens arrays constituting an integrator, a first condenser lens, and a second condenser lens are arranged in this order. An illumination optical system is disclosed.
Patent Document 2 discloses an image display device in which light from two semiconductor lasers is synthesized using a prism and a lens system so as to reduce unevenness in the light amount distribution.
JP 2001-343706 A JP 2003-066369 A

However, the configuration of Patent Document 1 has a drawback in that the number of parts is large and downsizing is restricted.
In Patent Document 2, light from two semiconductor lasers is synthesized using a prism and a lens system to reduce the unevenness of the light amount distribution. However, in this method, the number of light sources that can be synthesized is limited, and a large number of light sources are used. Has the disadvantage of not being applicable.
Accordingly, the present invention has been made in view of the above points, and provides an illumination device that can be reduced in size and thickness, a light modulation device including the illumination device, and a projection display device. For the purpose.

In order to achieve the above object, the invention described in claim 1 includes a plurality of light emitting elements having non-uniform light distribution characteristics, and a coupling lens disposed corresponding to each of the plurality of light emitting elements. And an illumination device comprising a first lens array, a second lens array, and an illuminated surface, or between the coupling lens and the first lens array, or between the coupling lens and the first lens array. An optical element for reducing a non-uniform light amount distribution on the illuminated surface due to the light distribution characteristic of the light emitting element is disposed in the vicinity of the lens array.
According to a second aspect of the present invention, in the illuminating device according to the first aspect, the optical element is a refractive optical element disposed corresponding to the light emitting element or the coupling lens, respectively. To do.
According to a third aspect of the present invention, in the illuminating device according to the first or second aspect, the optical element is a substantially afocal optical system composed of at least two lenses and has a lens center. When the afocal magnification at the center of the lens is Mc and the afocal magnification at the lens peripheral portion is Mm, Mc / Mm> 1.
According to a fourth aspect of the present invention, in the illuminating device according to the first or second aspect, the optical element is a substantially afocal optical system having at least two refracting surfaces, and a lens center portion. When the afocal magnification at the center of the lens is Mc and the afocal magnification at the lens periphery is Mm, Mc / Mm> 1.
According to a fifth aspect of the present invention, in the illumination device according to the third or fourth aspect, when the afocal magnification of the lens peripheral portion is Mm, | Mm | ≈1. .

According to a sixth aspect of the present invention, in the illuminating device according to the first or second aspect, the optical element is an optical system having at least two conical prism surfaces, and a central portion light beam and a peripheral portion. The light beam is configured to be interchanged with each other.
According to a seventh aspect of the present invention, there is provided a light modulation device configured by arranging a light modulation means on the illuminated surface of the lighting device according to any one of the first to sixth aspects. .
The invention according to claim 8 is a projection type display device comprising the illumination device according to any one of claims 1 to 6, wherein each light emitting element is a single light emitting element and has a plurality of colors. A light modulation means that is time-division driven in synchronization with the emission timing of each color light emitted sequentially from the light emitting element, and a projection that projects the light modulated by the light modulation means And means.
The invention according to claim 9 is a projection display device including the illumination device according to any one of claims 1 to 6, wherein each of the light emitting elements is a single color of the light emitting element alone. A light modulation means capable of emitting colored light, including three or more types of light emitting elements that emit different colored lights, and driven in a time-sharing manner in synchronization with the emission timing of each color light emitted sequentially from the light emitting elements; Projection means for projecting light modulated by the light modulation means.

A tenth aspect of the present invention is a projection display device including the lighting device according to any one of the first to sixth aspects, wherein each of the light emitting elements emits color lights of different colors. A plurality of surface light sources capable of emitting, a plurality of light modulating means for modulating each color light emitted from the surface light source, a color combining means for combining the color lights modulated by the plurality of light modulating means, and the color combining And projection means for projecting light synthesized by the means.
The invention described in claim 11 is a projection display device including the illumination device according to any one of claims 1 to 6, wherein the light emitting element is a white LED, and the white LED The light modulation means provided with the color filter which converts the white light radiate | emitted from a several color, and the projection means which projects the light modulated by this light modulation means are characterized by the above-mentioned.
According to a twelfth aspect of the present invention, in the light modulation device according to the seventh aspect, between the second lens array and the light modulation means, the polarization conversion that aligns the light emitted from the light emitting element with polarized light in one direction. An element is provided.
The invention according to claim 13 is the projection type display device according to any one of claims 8 to 11, wherein the light emitting element is placed between the second lens array and the light modulation means. A polarization conversion element that aligns incident light with polarized light in one direction is provided.
According to a fourteenth aspect of the present invention, in the light modulation device according to the seventh aspect, at least one relay lens is provided between the second lens array and the light valve.
The invention according to claim 15 is the projection type display device according to any one of claims 8 to 11, wherein at least one relay lens is provided between the second lens array and the light valve. It is characterized by providing.

  According to the present invention, a non-illuminated surface caused by the light distribution characteristic of the light emitting element is provided between the coupling lens and the first lens array or in the vicinity of the coupling lens and the first lens array. By arranging an optical element that reduces the uniform light amount distribution, the lighting device can be reduced in size and thickness.

Hereinafter, this embodiment of the present invention will be described.
FIG. 1 is a diagram showing the configuration of the illumination device of the present embodiment.
In FIG. 1, 1 is a light emitting element array such as an LED array, 2 is a coupling lens that has a large NA and converts divergent light into (quasi) parallel light, 3 is a first lens array, and 4 is a second lens array. The lens array 5 is an illuminated surface.
The first and second lens arrays 3 and 4 have effective dimensions similar to the illuminated surface 5 and receive light from the coupling lens 2 to mainly control spherical aberration and form a secondary light source image.
In the second lens array 4, the light source has a size, or the direction of off-axis light (not shown) due to an arrangement error of each element is changed to guide the light onto the surface to be illuminated 5. To do.
In FIG. 1, when the light distribution characteristics of each light emitting element of the light emitting element array 1 are indicated by the length of the arrow →, this distribution exists even after being converted into parallel light by the coupling lens, and on the illuminated surface. Create unevenness in the light distribution.
The optical element 6 is an element for reducing the light distribution, and is disposed between the coupling lens 2 and the first lens array 3. In FIG. 1, the light is converted almost uniformly by the optical element 6, and then illuminated using an optical system such as a first lens array 3, a second lens array 4, a relay lens or a field lens (not shown). By irradiating the surface 5, it becomes possible to reduce the non-uniform light amount distribution of the surface 5 to be illuminated.
Note that the arrangement of the coupling lens 2 and the first lens array 3 may be made to correspond and the functions may be integrated and replaced with, for example, one lens. In that case, the optical element 6 for reducing unevenness may be disposed in the vicinity of the lens.

As described above, in the illumination device of the present embodiment, the light emitting element array 1 having a plurality of light emitting elements having non-uniform light distribution characteristics in order from the light source side, and each light emitting element of the light emitting element array 1 has a one-to-one correspondence. The coupling lens 2, the first lens array 3, the second lens array 4, and the surface to be illuminated 5 are disposed corresponding to each of the coupling lens 2 and the first lens array 3. An optical element 6 that reduces the non-uniform light amount distribution on the illuminated surface 5 due to the light distribution characteristic of the light emitting element is disposed between them. Thereby, size reduction and thickness reduction of an illuminating device can be achieved. Since the LED array 1 is used as the light source, the cooling fan is unnecessary because the heat generation is small, so that a quiet illumination device can be realized.
The optical element 6 is disposed between the coupling lens 2 and the first lens array 3 because the light paths from the light emitting elements of the light emitting element array 1 are separated without overlapping each other. This is because the luminous flux from each light emitting element has an appropriate width and is suitable for converting the light distribution characteristics.
The optical element 6 that reduces the non-uniform light amount distribution on the surface to be illuminated 5 is a refractive optical element that is disposed on the light emitting element of the light emitting element array 1 or the coupling lens 2 in a one-to-one correspondence. In this case, the first lens array 3 and the second lens array 4 do not necessarily correspond to each other. In addition, since the refractive optical element is an array, it is desirable that the width of the light beam is not changed greatly by incident / exit, and that the shape can be molded by a mold for productivity. Further, since the coupling lens 2 and the first lens array 3 arranged adjacent to each other are also refractive optical elements, a part or all of the optical element 6 that reduces the non-uniform light amount distribution is integrated with the adjacent optical component. The number of parts can be reduced.
The optical element 6 is an almost afocal optical system composed of at least two lenses, and has different afocal magnifications at the lens central portion and the peripheral portion, and the lens central portion (= center portion) has an afocal magnification. Mc / Mm> 1 when the focal magnification is Mc and the afocal magnification of the lens peripheral portion (= marginal portion) is Mm.
In such a configuration, in principle, it is possible to achieve uniformity by giving an afocal magnification proportional to the light intensity. The afocal magnification may be continuously changed from the center of the lens toward the peripheral edge, and the magnification can be created stepwise.

FIG. 2 is a diagram showing a configuration example of the optical element.
For example, when the coupling lens captures ± 60 ° of the divergent light of the light source, the Lambert distribution is expressed by a cosine function, so when the intensity at the center of the coupling lens is 1, the intensity at the peripheral edge Is cos (60 °) = 0.5, and the intermediate portion has an intermediate value indicated by a cosine function.
FIG. 2 shows the afocal magnification of the light beam in the central part as Mc = 1.4 and the peripheral part as Mm = 0.7. In this case, the intensity distribution of the light emitted from the optical element 6 is made uniform. be able to. In the case where the two lenses 6a and 6b are used, the shape becomes complicated. Therefore, it is possible to improve the workability by using three or more lenses.
Further, it is not necessary to have the same afocal magnification in a two-dimensional direction, and an anamorphic system may be used to make the light quantity distribution uniform in each direction.
Further, the optical element 6 can be a substantially afocal optical system having at least two refracting surfaces. In this case, when the afocal magnification is different at the lens center and the peripheral portion, Mc / Mm> 1 when the afocal magnification at the lens central portion is Mc and the afocal magnification at the lens peripheral portion is Mm. It is also possible to do.
Also, as shown in FIG. 3, the optical element 6 is made up of one component by making the planes of the two lenses face each other, filling the air portion with the lens material and resetting the distance optimally. A simple configuration is also possible.
Further, when the afocal magnification Mm of the lens peripheral portion is | Mm | ≈1, the optical element 6 can make the shape of the peripheral portion substantially parallel to the array surface (surface orthogonal to the optical axis). As a result, the fluctuation at the boundary between and becomes smooth, which is advantageous in manufacturing the mold.
The optical element 6 is an optical system having at least two conical prism surfaces, and can be configured such that the central beam and the peripheral beam are interchanged.

FIG. 4 is a diagram showing another configuration example of the optical element.
The optical element 6 shown in FIG. 4 is composed of a pair of prisms 6c and 6d.
In such a configuration, the simulated intensity shows that the center intensity is distributed in the periphery and the periphery intensity is distributed in the center, so that this effect is applied to half of the light-emitting elements and the remaining half. As it is, it is expected that the objects with distributions will be combined and disappear.
Actually, there is an influence of the size of the light source, a deviation from the Lambertian distribution, a light beam (not shown), etc., and a light emitting element to which the optical element 6 is applied so that the illuminated surface 5 has a uniform light amount, and the optical element 6 It is preferable to determine the ratio of light emitting elements that are not applied.
Further, as shown in FIG. 5, the optical element 6 can be constituted by one component if the parallel plane sides of the two conical plates 6c and 6d face each other and the space between them is filled with the same material.
Further, when the light modulation device is configured by arranging the light modulation means on the surface to be illuminated 5 of the illumination device of the present embodiment as described above, it is small in size and generates little heat, and unevenness in the light amount distribution can be reduced. For example, when a transmissive LCD, which is a transmissive light modulator, is arranged in the light modulation means, the light modulation device becomes a display device, and the display can be observed by directly observing or using an eyepiece such as a magnifying glass. It becomes possible. In addition, since there is little heat generation, a cooling fan is unnecessary, and a quiet display device can be realized.

FIG. 6 is a diagram illustrating the configuration of the optical system of the projection display device.
In addition, the same code | symbol is attached | subjected to the same site | part as FIG. 1, and description is abbreviate | omitted.
In the projection display device shown in FIG. 6, the coupling lens has a two-lens configuration. Further, an optical element 6 that reduces unevenness of the light amount distribution on the surface to be illuminated 5 is arranged between the coupling lens 2 and the first lens array 3. The relay lens 11 and the field lens 12 jointly change the direction of the chief ray emitted from the second lens array 4 and guide it to the center of the illuminated surface 5 to obtain efficient and non-uniform illumination. A light modulation element is disposed on the illuminated surface 5, and the modulated light beam is projected onto the display surface 14 via the projection optical system 13. The projection optical system is preferably telecentric.
Since LEDs and LD do not contain infrared rays (heat) in the emitted light, plastic lenses can be used even near the light source. For this reason, a member in the vicinity of the light source can be formed by molding, the cost can be reduced, and mass production of aspherical surfaces and special surfaces becomes relatively easy and uniformity can be improved. There is an advantage that it can be made lighter than a glass lens.
Of the lenses used in the illumination optical system, it is effective to use at least one Fresnel lens. In particular, when a lens is used for the converging optical element, the center thickness tends to increase, and replacement with a Fresnel lens makes it possible to reduce the thickness and weight. A diffractive surface can be used in combination to reduce the color difference of the illumination light.
As described above, when the illumination device of the present embodiment is applied to a projection display device, each light emitting element of the light emitting element array 1 can emit light of a plurality of colors with a single light emitting element, and sequentially from the light emitting elements. If a light modulation element (light modulation means) driven in a time-sharing manner in synchronization with the emission timing of each color light emitted to the light and a projection means for projecting light modulated by the light modulation element, Thus, it is possible to realize a projection-type color display device that has the characteristics of the illuminating device and that can be particularly miniaturized.
In addition, each light emitting element of the light emitting element array 1 of the lighting device can emit one color of light with a single light emitting element, and further includes three or more types of light emitting elements with different emitted color lights. If a light modulation element that is time-division driven in synchronization with the emission timing of each color light emitted to the light source and a projection means that projects light modulated by the light modulation element are provided, light emitting elements of different types The same effect can be obtained by using.

Further, each light emitting element of the light emitting element array 1 is a plurality of surface light sources capable of emitting color lights of different colors, a plurality of light modulation elements for modulating each color light emitted from the surface light source, and a plurality of light modulation elements. If it is provided with a color synthesizing means for synthesizing the modulated color light and a projection means for projecting the light synthesized by the color synthesizing means, it is effective in a bright specification even if it is somewhat larger. Other features can realize a projection display device that is maintained.
Furthermore, each light emitting element of the light emitting element array 1 is a white LED, and a light modulation element provided with a color filter for converting white light emitted from the LED into a plurality of colors and light modulated by the light modulation element are projected. By providing the projection means, it is possible to provide a projection display device capable of selecting a wide range of light-emitting elements and adapting to various specifications and adjusting color balance.
Furthermore, a light modulation device or a projection display device is configured by providing a polarization conversion element for aligning the emitted light of the light emitting element in one direction of polarization between the second lens array 4 of the illumination device and the light modulation element. Then, the light modulation element is effective in an LCD using polarized light, and the light use efficiency can be improved.
Furthermore, if a light modulation device or a projection display device provided with at least one relay lens between the second lens array 4 and the light valve is configured, light can be effectively collected on the illuminated surface 5. In addition to being bright, the load on the light emitting element can be reduced and power can be saved.

It is the figure which showed the structure of the illuminating device of this embodiment. It is the figure which showed one structural example of the optical element. It is the figure which showed one structural example of the optical element. It is the figure which showed one structural example of the optical element. It is the figure which showed one structural example of the optical element. It is a figure explaining the structure of the optical system of a projection type display apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... LED array, 2 ... Coupling lens, 3 ... 1st lens array, 4 ... 2nd lens array, 5 ... Illuminated surface, 6 ... Optical element, 6a 6b ... Lens, 6c 6d ... Prism (conical plate ) 11 relay lens 12 field lens 13 projection optical system 14 display surface

Claims (15)

A plurality of light emitting elements having non-uniform light distribution characteristics; a coupling lens disposed corresponding to each of the plurality of light emitting elements; a first lens array; a second lens array; In an illumination device comprising an illuminated surface,
Non-uniformity of the illuminated surface due to the light distribution characteristic of the light emitting element between the coupling lens and the first lens array or in the vicinity of the coupling lens and the first lens array An illumination device comprising an optical element for reducing a light amount distribution.   The illuminating device according to claim 1, wherein the optical element is a refractive optical element disposed corresponding to the light emitting element or the coupling lens. The lighting device according to claim 1 or 2,
The optical element is a substantially afocal optical system composed of at least two lenses, and has different afocal magnifications at the lens central portion and the peripheral portion, and the afocal magnification at the lens central portion is Mc. When the afocal magnification at the periphery is Mm,
Mc / Mm> 1
A lighting device characterized by the above. The lighting device according to claim 1 or 2,
The optical element is a substantially afocal optical system having at least two refracting surfaces, and has different afocal magnifications at the lens central portion and the peripheral portion. The afocal magnification at the lens central portion is Mc, and the lens periphery When the afocal magnification of the part is Mm,
Mc / Mm> 1
A lighting device characterized by the above. In the illuminating device of Claim 3 or Claim 4,
When the afocal magnification at the lens periphery is Mm,
| Mm | ≒ 1
A lighting device characterized by the above.   3. The illumination device according to claim 1, wherein the optical element is an optical system having at least two conical prism surfaces, and is configured such that a central beam and a peripheral beam are switched with each other. A lighting device characterized by that.   A light modulation device comprising: a light modulation unit disposed on the surface to be illuminated of the illumination device according to claim 1.   7. A projection display device comprising the illumination device according to claim 1, wherein each of the light emitting elements is capable of emitting a plurality of colors of light with a single light emitting element, and the light emitting element. A light modulation unit that is driven in a time-sharing manner in synchronization with the emission timing of each color light that is sequentially emitted from the element; and a projection unit that projects the light modulated by the light modulation unit. Projection display device.   7. A projection display device comprising the illumination device according to claim 1, wherein each of the light emitting elements can emit a single color of light when the light emitting element alone is used, and the emitted color light. Are provided with three or more types of light emitting elements different from each other, light modulating means driven in a time-sharing manner in synchronization with the emission timings of the respective color lights sequentially emitted from the light emitting elements, and light modulated by the light modulating means And a projection means for projecting.   It is a projection type display apparatus provided with the illuminating device of any one of Claim 1 thru | or 6, Comprising: Each said light emitting element is a some surface light source which can radiate | emit color light of a mutually different color, A plurality of light modulation means for modulating each color light emitted from the surface light source, a color composition means for synthesizing the color lights modulated by the plurality of light modulation means, and a projection for projecting the light synthesized by the color composition means And a projection type display device.   7. A projection type display device comprising the illumination device according to claim 1, wherein the light emitting element is a white LED, and the white light emitted from the white LED is a plurality of colors. A projection type display device comprising: a light modulation means provided with a color filter for converting into a light filter; and a projection means for projecting light modulated by the light modulation means.   8. The light modulation device according to claim 7, further comprising: a polarization conversion element that aligns the light emitted from the light emitting element with polarized light in one direction between the second lens array and the light modulation unit. apparatus.   12. The projection type display device according to claim 8, wherein the light emitted from the light emitting element is aligned in one direction between the second lens array and the light modulation unit. A projection display device comprising an element.   8. The light modulation device according to claim 7, further comprising at least one relay lens between the second lens array and the light valve.   12. The projection display device according to claim 8, further comprising at least one relay lens between the second lens array and the light valve. .

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