JPH1152889A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce heat generation in a light source and to reduce a space for color resolution. SOLUTION: This device is provided with a transmission type space modulation element two-dimensionally arranging N (≫1) pieces of color pixels adjacently arranged with three colors pixels and displaying a three colors image, a drive means 12 displaying respective color images on it, a micro-lens array 14 arranging N micro-lenses one to one corresponding to repective color pixels, (n) (<N) three colors LED light sources 161, 162,... constituting three colors LEDs with a block, a condenser lens array 18 one-dimensionally or two- dimensionally arranging (n) condenser lenses one to one corresponding to them corresponding to the transmission type space modulation element, a display medium 30 displaying the color image of the transmission type space modulation element and image forming optical systems 20, 22 projecting the color image on this medium 30, and is constituted so that light from respective color LEDs are made incident on respective colors pixels on respective color pixels corresponding to the condenser lenses by the condenser lenses and individual micro- lenses corresponding to them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image display device.

[0002]

2. Description of the Related Art As an image display device for projecting and displaying a color image on a screen, a device using a "single-plate type liquid crystal color panel" is known. In this image display device, red, green, and blue images are simultaneously displayed on a single-panel type liquid crystal color panel, and white light from a white light source is reflected by three dichroic mirrors as "three colors (red, Green
The collimated light beam of blue) is irradiated with light that has been color-separated, and the light beam transmitted through the liquid crystal color panel is projected and imaged on a screen by an imaging optical system to display a color image.

[0003] This image display device can display a color image on a relatively large screen, but requires a strong light source close to 100 W like a metal halide lamp, and requires a special cooling means due to a large amount of heat generated by the light source. In addition, there is a problem that energy consumption for cooling is large. Further, since three dichroic mirrors are used for color separation of a light beam from a light source, a space for color separation is increased, and it is difficult to make the image display apparatus body compact.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to effectively reduce the heat generated by a light source and to reduce the space for the light source and color separation in a projection type image display device.

[0005]

An "image display device" according to the present invention comprises a transmission type spatial modulation element, a driving means, a microlens array, a three-color LED light source, a condenser lens array, a display medium, , An imaging optical system. The “transmission type spatial modulation element” is a device that displays the A color when the three color images forming the color image are an A image, a B image, and a C image.
A color pixel, a B color pixel displaying B color, and a C color pixel displaying C color are arranged adjacent to each other to form a unit color pixel, and N (>> 1) such color pixels are provided. These elements are two-dimensionally densely arranged and integrated to display an A color image, a B color image, and a C color image. Each color pixel is a transmissive type. For example, in a two-dimensional array of the A color pixels, the distribution of the A color pixels in the transmissive state forms an “A color image”. As the transmissive spatial light modulator, the above-mentioned “single-plate type liquid crystal color panel” can be suitably used. The “driving unit” is a unit for displaying the A-color image, the B-color image, and the C-color image on the transmission type spatial modulation element, has an interface, and operates in accordance with color image information input from an external device such as a computer. The transmissive spatial light modulator is driven to display the respective color images.

[0006] The "microlens array" is a two-dimensional array of N microlenses.
Each microlens constituting the microlens array corresponds to each color pixel of the transmissive spatial light modulator in one-to-one correspondence. "Three-color LED light source" is A-color L that emits A-color light
An ED, a B-color LED that emits B-color light, and a C-color LED that emits C-color light are configured in one block, and n (<N) such three-color LED light sources are used. The “condenser lens array” is formed by arranging n condenser lenses one-dimensionally or two-dimensionally in correspondence with the transmissive spatial light modulator. And one-on-one
It is deployed to correspond to. The “display medium” is a medium that displays a color image displayed on the transmissive spatial light modulator. “Imaging optical system” is an optical system that projects and forms a color image displayed on a transmission type spatial modulation element toward a display medium. And each color LED of each three color LED light source
Of light from the light source enters a color pixel of a corresponding color in each color pixel corresponding to the condenser lens by the condenser lens corresponding to each of the three-color LED light sources and the individual microlenses corresponding to the condenser lens. (Claim 1).

That is, one three-color LED corresponds to one condenser lens, and one condenser lens corresponds to a plurality of microlenses in a microlens array. For example,
Assuming that m microlenses correspond to one condenser lens, m microlenses correspond to m color pixels, and each color pixel is composed of A color pixel, B color pixel, and C color pixel. Have been. Therefore, when, for example, an A-color LED of one three-color LED light source is turned on, this A-color LE
The A-color light from D is applied to m microlenses by a condenser lens corresponding to the three-color LED light source to which the A-color LED belongs. Each of these m microlenses is
The irradiated A-color light is made incident on the A-color pixels in the color pixels corresponding to the respective microlenses.

It is preferable that the positional relationship between the microlens array and the transmissive spatial light modulator is "provided that the microlens array is closely attached to or very close to the transmissive spatial light modulator". Also, each three-color LED light source is
The central LED light source in the three-color LED light source can be disposed at a focal position on the optical axis of the condenser lens corresponding to the three-color LED light source (claim 3). The A, B, and C colors are not particularly limited as long as they can express a color image by combining them, and various combinations are possible.
The “combination of red, green and blue for B and C colors, respectively” is preferable in that LEDs emitting these red, green and blue lights can be obtained at low cost. An image forming optical system for projecting and forming a color image displayed on the transmission type spatial modulation element toward a display medium can be constituted by “a Fresnel lens as a field lens and an image forming lens system”. 5). In addition, each color L in each three-color LED light source
The emission current of the ED can be "adjustable" (claim 6). By doing so, the color balance of the display color image can be adjusted.

Further, a cooling means for disposing a plurality of three-color LED light sources on the same substrate and cooling the three-color LED light sources via the same substrate can be provided. The cooling means may be "active cooling means" such as blowing cooling air, "passive cooling means" such as providing cooling fins on the same substrate, or a combination of cooling fins and cooling air. Cooling means can also be used. By providing such a cooling means, the emission intensity of the LED used as the light source is increased, and the displayed image can be brightened. As a recording medium for displaying a color image,
Use ordinary projector screens and concave mirrors (reflection and imaging of color images projected and formed by the imaging optical system so that they can be observed as virtual or real images), or "hologram combiners" that have the function of concave mirrors You can also. The hologram combiner is a flat panel formed by holograms. However, the hologram combiner can correct a distortion of a display color image, or can combine and observe an image behind the panel and a display color image.

In the image display device of the present invention, the light source is L
Since an ED is used, a color image display on a relatively small screen is suitable. As a display medium, a screen having a diagonal length of 30 inches or less (a screen for a projector, a concave mirror, or a hologram combiner) is suitable. With a screen of about the size, the image display device can be suitably realized as a desktop type of personal use.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 10 denotes a single-panel liquid crystal color panel as a "transmission type spatial modulation element".
Reference numeral 12 denotes a driving circuit as “driving means”, reference numeral 14 denotes a microlens array, reference numerals 161, 162, and 163 denote three-color LED light sources, reference numeral 18 denotes a condensing lens array, and reference numeral 1.
Reference numeral 7 denotes a substrate, reference numeral 20 denotes an imaging lens system, reference numeral 22 denotes a Fresnel lens, and reference numeral 30 denotes a screen as a “display medium”. In the embodiment described below, it is assumed that the colors A, B, and C are red, green, and blue, respectively (claim 4).

The liquid crystal color panel 10 is a liquid crystal panel for displaying a color image as a three-color image of red, green, and blue. The individual red, green, and blue pixels are minute liquid crystal switches.
The light transmission intensity can be controlled. The red pixel, the green pixel, and the blue pixel constitute one unit of “color pixel” adjacent to each other, and such a color pixel is N (>>)
1) two-dimensionally arranged liquid crystal color panels 1
0.

A color image to be displayed is input to the drive circuit 12 as "color image information" from an external device such as a computer or a video deck. The drive circuit 12 sets the red pixels of the liquid crystal color panel 10 in a light transmitting state according to the “red image information” of the color image information, and according to the “green image information” and the “blue image information”, respectively. To a transparent state. Therefore, for example, the two-dimensional distribution of “transparent red pixels” in the liquid crystal color panel 10 represents a “red image”. A red image can be displayed by transmitting red light through the red image and forming the transmitted red light on the screen 30. Similarly, a “green image” can be displayed by selectively transmitting green light to a “green image” represented by a distribution of green pixels in a transmissive state and forming the transmitted light on the screen 30, A “blue image” can be displayed by selectively transmitting blue light to a “blue image” represented by a distribution of blue pixels in a transmissive state and forming the transmitted light on the screen 30. By displaying the “red image, green image, and blue image” on the screen 30 at the same time, a color image is displayed.

The microlenses 14 are two-dimensionally arrayed with microlenses. Each microlens corresponds to a “color pixel” in the liquid crystal color panel 1: 1. That is, the number of microlenses is N, which is the same as the number of color pixels, and the two-dimensional array of microlenses is "combinedly identical" with the two-dimensional array of color pixels.

There are a total of n (<N) three-color LED light sources 161, 162, 163, etc., which are usually arranged two-dimensionally. The individual three-color LED light sources include a red LED (LED emitting red light), a green LED (LED emitting green light), and a blue LED (LE emitting blue light).
D) are brought close to each other and integrated into one block, and the red LED, green LED,
The array of blue LEDs corresponds to the array of red, green, and blue pixels in each color pixel. Since n three-color LED light sources are provided for N color pixels, one three-color LED light source corresponds to N / n color pixels.

The condensing lens array 18 has the same number (n) of the same condensing lenses as the three-color LED light sources arranged in an array. The array arrangement corresponds to the three-color LED light sources on a one-to-one basis. Array. The Fresnel lens 22 has a function as a “field lens” and forms an “imaging optical system” with the imaging lens 20.

That is, in the image display device shown in the embodiment of FIG. 1, a red pixel, a green pixel and a blue pixel are arranged adjacent to each other to form a "unit color pixel", and such a color pixel is N ( >> 1) two-dimensionally arranged two-dimensionally densely integrated transmission type spatial modulation elements 10 for displaying red, green and blue images, and red, green, and blue A driving unit 12 for displaying an image, a microlens array 12 in which N microlenses are arranged in one-to-one correspondence with each color pixel of the transmissive spatial modulation element 10, a red LED, a green LED, and a blue LED And n (<N) three-color LED light sources 161, 162,
163,. . And n condensing lenses arranged in one-to-one correspondence with the three-color LED light sources 161 and the like, one-dimensionally or two-dimensionally arranged in correspondence with the transmissive spatial light modulator 10. Condensing lens array 18 and display medium 3 for displaying a color image displayed on transmissive spatial light modulator 10
0 and the transmission type spatial modulation element 1 toward the display medium 30.
Image forming optical systems 20 and 22 for projecting and forming a color image displayed at 0 (claim 1).

The microlens array 14 is provided in close contact with the liquid crystal color panel 10 which is a transmission type spatial modulation element. By providing the microlens array 14 in close contact with the liquid crystal color panel 10, the positional relationship between each microlens and the color pixel can be accurately determined.

FIG. 2 shows the embodiment of FIG.
Liquid crystal color panel 10 and micro lens array 14
And a portion of the condenser lens array 18 corresponding to the three-color LED light source 162. As shown in FIG. 2, the three-color LED light source 162 includes a red LED 162 </ b> R, a green LED 162 </ b> G, and a blue LED 162 </ b> B that are closely arranged and integrated as one block. Has been deployed accordingly. The condenser lens 182 covers the color pixels in the two-dimensional area indicated by the symbol D in the figure.

The liquid crystal color panel 10 includes color pixels EC.
Are two-dimensionally arrayed, but the individual color pixels EC
Is a pixel in which a red pixel ER for displaying red, a green pixel EG for displaying green, and a blue pixel EB for displaying blue are arranged adjacent to each other. One micro lens of the micro lens array corresponds to each of these color pixels EC, and the optical axis of each micro lens passes through the center of the green pixel EG in the corresponding color pixel.
The microlens in the two-dimensional area D corresponds to the condensing lens 182, and the light emitted from each color light source of the three-color LED light source 161 is condensed by the condensing lens 182 and all the light in the two-dimensional area D Incident on the microlens. The positional relationship between the other three-color LED light sources (not shown in FIG. 2), the condenser lens, the microlens array, and the liquid crystal color panel is the same.

As shown in FIG. 2, the three-color LED light source 162
The central LED light source (162G) is a three-color LED
The condenser lens 182 is provided at a focal position on the optical axis corresponding to the light source 162 (claim 3). That is, the three-color LED light source 162 is on the focal plane of the condenser lens 182, and the red LE
The red luminous flux from D162R, the green luminous flux from the green LED 162G, and the blue luminous flux from the blue LED 162B all become “parallel luminous flux” when transmitted through the condenser lens 182. Of these, the green light flux is parallel to the optical axis of the condenser lens 182, and the red and blue light fluxes are
Are symmetrically inclined with respect to the optical axis. Here, considering light rays emitted from the individual LEDs of the three-color LED light source 162 in parallel to the optical axis of the condenser lens 182, they travel as shown in FIG.
2 are refracted by the same microlens 14
2 is incident. The red, green, and blue light rays are refracted by the microlenses 142, respectively.
When the pixel reaches the corresponding color pixel of the color pixel corresponding to 2 and the pixel is in a transmission state, the pixel transmits the color pixel. The same applies to other light rays. That is, light from each color LED of the three-color LED light source 162 is condensed by the condensing lens 182 corresponding to the three-color LED light source 162 and the individual microlenses 142 corresponding to the condensing lens.
(In the two-dimensional area D). The same applies to the luminous flux from the other three-color LED light sources. In this way, red, green, and blue luminous fluxes transmitted through the red, green, and blue images displayed on the liquid crystal color panel 10 are obtained. The light beams of the three colors enter the imaging lens system 20 via a Fresnel lens 22 as a field lens, and are formed by an “imaging optical system” constituted by these components to form a screen 3 as a display medium.
0 is projected and imaged (claim 5), and the screen 3
A desired “color image” is displayed on the “0”. By using a Fresnel lens as a field lens in the imaging optical system, a bright color image can be formed without increasing the diameter of the imaging lens system 20. Each color LED in each of the three color LED light sources is "adjustable emission current" (claim 6), and adjusts the emission current while observing the color image displayed on the screen 30 (adjustment means in the drive circuit). Installed), it is possible to realize a color balance according to the preference.

As shown in FIG. 1, the three-color LED light source 16
1, 162, 163 and the like are provided on the same substrate 17. A radiation fin 17 </ b> A is provided on the substrate 17. As a result, the three-color LED light sources 161, 162 and the like are cooled via the substrate 17, and a bright color image can be displayed while always maintaining a high luminous intensity. The image display device of the embodiment shown in FIG. 1 is a desktop type of "personal use", and the screen 30 as a display medium is a "screen having a diagonal length of 20 inches" (claim 8). In addition, as a configuration of the entire image display apparatus, a portion except for the screen 30 in FIG. 1 may be configured as a “projector”, and the screen 30 may be configured separately. Can be projected onto the display medium via the appropriate “optical path bending means”. The two-dimensional arrangement of the color pixels may be a “matrix” or a so-called “staggered arrangement”.
Corresponding to these two-dimensional arrays, the microlens array of the microlens array also has a matrix or staggered shape.

[0023]

As described above, according to the present invention, a novel image display device can be realized. The image display device according to the present invention is a small three-color LED that generates a small amount of heat as a light source.
Since a light source is used, a dedicated cooling means is not required in the image display device, or even if it is necessary, a simple cooling fin or the like can be used, a large cooling space is not required, and as a light source, 3 that emits light of three colors individually
Since the color LED light source is used, the color separation of the light source light is unnecessary, and the space for the color separation is unnecessary, so that the image display device can be made compact (claims 1 to 8).

According to the second aspect of the present invention, the positional relationship between the individual microlenses and the color pixels can be accurately determined by providing the microlens array in close contact with or very close to the liquid crystal color panel.

According to the fifth aspect of the present invention, by using a Fresnel lens as a field lens in the imaging optical system, the diameter of the imaging lens system can be increased without increasing the aperture.
A bright color image can be formed, and the color balance according to the preference can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram for describing an embodiment of the present invention.

FIG. 2 is a diagram for explaining an optical function in the embodiment.

[Explanation of symbols]

 Reference Signs List 10 transmission type spatial modulation element 14 microlens array 18 condenser lens array 161, 162,. . Three-color LED light source 20 Imaging lens system 22 Fresnel lens 30 Display medium

Claims (8)

[Claims] When the three color images constituting a color image are an A image, a B image and a C image, an A color pixel displaying the A color, a B color pixel displaying the B color, and a C color are displayed. The C color pixels to be displayed are arranged adjacent to each other to form a unit color pixel, and such color pixels are N (>
> 1) two-dimensionally arranged two-dimensionally densely and integratedly to display an A-color image, a B-color image and a C-color image; Image, B color image, C
Driving means for displaying a color image; a microlens array in which N microlenses are arranged in one-to-one correspondence with each color pixel of the transmissive spatial modulation element; and n (<N) light condensing elements A condensing lens array in which lenses are arranged one-dimensionally or two-dimensionally in correspondence with the above-mentioned transmissive spatial light modulator, an A-color LED emitting A-color light, and a B-color LED emitting B-color light And n three-color LED light sources configured as one block of a C-color LED that emits C-color light, a display medium that displays a color image displayed on the transmissive spatial light modulator, and a display medium. An image forming optical system for projecting and forming a color image displayed on the transmission type spatial light modulator, wherein each of the n three-color LED light sources is a respective condenser lens of the condenser lens array. And one-to-one, three color LED lights The light from each color LED is collected by a condensing lens corresponding to each three-color LED light source and an individual microlens corresponding to this condensing lens. An image display device configured to be incident on a pixel. 2. The image display device according to claim 1, wherein the microlens array is provided in close contact with or very close to the transmissive spatial light modulator. 3. The image display device according to claim 1, wherein a central LED light source in each of the three-color LED light sources is a three-color LED light source.
An image display device provided at a focal position on an optical axis of a condenser lens corresponding to a color LED light source. 4. The image display device according to claim 1, wherein the colors A, B, and C are red, green, and blue, respectively. 5. The image display device according to claim 1, wherein the imaging optical system comprises a Fresnel lens as a field lens and an imaging lens system. Image display device. 6. The image display device according to claim 1, wherein the emission current of each color LED in each of the three color LED light sources is adjustable. 7. The image display device according to claim 1, wherein a plurality of three-color LED light sources are provided on a same substrate, and cooling means for cooling the three-color LED light sources via the same substrate. An image display device comprising: 8. The image display device according to claim 1, wherein the display medium is a screen, a concave mirror or a hologram combiner having a diagonal length of 30 inches or less.