JP2003021804A - Picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture display device which has a low power consumption and less color slippage and is suitable for miniaturization and is capable of displaying a color picture. SOLUTION: A light source group 100 consists of light sources 101, 103, and 105 which have red, green, and blue surface light emission type LEDs 101a to 101n, 103a to 103n, and 105a to 105n one-dimensionally arranged at equal intervals respectively. In light sources 101, 103, and 105, LEDs are so arranged that scanning lines 111i, 113i, and 115i may overlap. A galvano-mirror 109 is moved to form scanning lines 111a to 111n, 113a to 113n, and 115a to 115n of which the number corresponds to the number of three-color light emitting elements. Since LEDs 101a to 101n, 103a to 103n, 105a to 105n are arranged at equal intervals, scanning lines are formed at equal intervals.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a laser beam and an LED.
The present invention relates to an image display device that scans an array of light sources, and displays a television screen, a computer screen, or the like on a screen, a wall, or the like.

[0002]

2. Description of the Related Art Conventionally, a display device for displaying two-dimensional image information by arranging light emitting elements such as LEDs in a two-dimensional manner has been widely put into practical use, and such a two-dimensional image information is used by a projection optical system. There is also a proposal for a projector that projects images on a screen.

However, in such a device, LE
Since the number of pixels of D is the same as the number of pixels of the display image, a huge number of LEDs are required to display a high resolution image. For example, to display a color image with a resolution of 800 dots x 600 dots, 1440000 L
The ED is required, which causes problems such as an increase in size of the device, an increase in power consumption, and an increase in cost. Therefore, it is difficult to apply it to a portable small projector.

In order to avoid such a problem, a device has been proposed which projects two-dimensional image information by arranging a plurality of light emitting elements one-dimensionally and scanning a light beam from them in a direction orthogonal to each other. There is. For example, FIG. 6 shows Japanese Patent No. 2823.
This shows the optical system disclosed in Japanese Patent Laid-Open No. 330. In the figure, reference numeral 621 indicates red LEs arranged in the direction perpendicular to the paper surface.
D array light source, 622 is a green LED array light source arranged in the vertical direction of the paper surface, and 623 is a blue LED array light source arranged in the vertical direction of the paper surface. 624 (625, 6
26 and 627) is a color combining prism. 6
Reference numeral 02 is a resonance mirror, and 603 is a lens. The virtual image A appears on the eyes B of the observer.

There is also an example disclosed in Japanese Patent Laid-Open No. 2001-4950. FIG. 7 shows a schematic diagram thereof. 703-1 to 703-600 are LEDs incorporating three colors of R, G, and B, and 703 is 600 LEs.
The light source is a D array. 704 is a condenser lens, 7
Reference numeral 05 denotes an optical fiber, and the light from the light source 703 is coupled to the optical fiber 705 via the condenser lens 704. 70
Reference numeral 6 denotes a light emitting array, which comprises LED light guided by an optical fiber 705 at predetermined intervals. Light emitting array 706
Light from the condenser lens 706a and the polygon mirror 70
7, the distortion correction lens 708, and the projection lens 709 are projected onto the screen 750.

There is also an example disclosed in Japanese Patent Laid-Open No. 2001-117505. FIG. 8A is a schematic diagram thereof, and FIG. 8B is a schematic diagram of the light source unit. 830R, 830G, and 830B are a red light source, a green light source, and a blue light source, respectively, 831R and 832R are red LED arrays in which red LEDs 810R are arranged in a row, and 831G and 832G are green LED arrays in which green LEDs 810G are arranged in a row. Yes, 831B, 832B
Is a blue LED array in which blue LEDs 810B are arranged in a line. Reference numeral 812 is a condenser lens, 814 is a horizontal scanning mirror, and 816 is a screen. Light from the red light source 830R, the green light source 830G, and the blue light source 830B is scanned by the horizontal scanning mirror 814 via the condenser lens 812, and as a result, an image is formed on the screen 816. In this example, a color combining element such as a color combining prism is unnecessary.

[0007]

However, in the example of the above-mentioned Japanese Patent No. 2823330, since the radiated light having the spread from the LED array light sources 621, 622 and 623 is collectively reflected, the resonance mirror is used. 602 must be larger than the length of the LED array light source, and there is a limit to miniaturization of the mirror. Further, the size of the mirror affects the resonance frequency and the operating power, which makes it difficult to display an image such as a moving image that requires high-speed scanning, and consumes high power. Also,
If the mirror size is not sufficient, the light utilization efficiency will differ depending on the position of the LED.
However, the controllability is not good because correction is required so that the light output of the LED in the peripheral portion becomes larger than that in the above. Further, the need for the color synthesizing prism 624 is also a factor that prevents miniaturization.

Further, in the example of Japanese Patent Laid-Open No. 2001-4950, since the condenser lens 704 and the optical fiber 705 are required for each LED, the number of parts increases and the coupling loss to the optical fiber increases. High precision alignment is required to reduce the size, and productivity is poor. Further, since the condenser lens 706a is provided at the exit of each optical fiber, the number of parts is increased, and also high-precision alignment is required, resulting in poor productivity. Furthermore, the reflecting surface of the polygon mirror 707 must be larger than the length of the light emitting array 706, which limits the miniaturization and increases the power consumption.

Further, in the example of Japanese Patent Laid-Open No. 2001-117505, there is no description about the distance between the condenser lens 812 and the scanning mirror 814. When the distance between the condenser lens 812 and the scanning mirror 814 is larger than the distance between the condenser lens 812 and the light sources (830R, 830G, 830B) as shown in this figure, it is necessary to increase the area of the scanning mirror 814. is there. If the mirror is large, the resonance frequency and the operating power are affected, and it becomes difficult to display an image such as a moving image that requires high-speed scanning, and the power consumption becomes high. If the mirror size is not enough, L
Since the light use efficiency varies depending on the position of the ED, it is necessary to perform correction so that the light output of the peripheral LED becomes larger than that of the central LED, and the controllability is poor.

Therefore, it is an object of the present invention to provide an image display device capable of displaying a color image suitable for downsizing, which has high productivity, low power consumption, little color unevenness.

[0011]

In order to solve the above-mentioned problems, the present invention provides a light source group having a plurality of light sources composed of the same number of light emitting elements as the number of scanning lines of an image, and a plurality of light source groups from the light source group. An image display device including a scanning element that reflects a light beam to scan in one direction, and a projection optical system that condenses the plurality of light beams on a display surface to form a plurality of scanning lines. Each of the scanning lines formed by the light beam from and the scanning line formed by the light beam at the corresponding position from the other light source forming the light source group overlap each other, It is characterized by being arranged.

More specifically, the light source group includes at least a light source including a red light emitting element, a light source including a green light emitting element, and a light source including a blue light emitting element.

Further, each light source constituting the light source group is integrated in the same plane, and each light emitting element constituting the light source is one-dimensional so that the intervals of the scanning lines on the display surface are constant. Alternatively, they are arranged two-dimensionally.

With the above structure, in the image display device, the light emitting elements in the respective light sources are arranged so that the scanning lines overlap with each other, so that the scanning lines corresponding to the respective light emitting elements of the three color light sources are formed in an overlapping manner. It

Further, the projection optical system includes a first condensing element provided between the light source group and the scanning element, and the focal plane on the scanning means side of the first condensing element or in the vicinity thereof. Is provided with a reflection mirror in the scanning means. Moreover,
The projection optical system includes a second condensing element provided between the scanning element and the display surface, and the light source group includes the first condensing element.
It may be provided on the focal plane of the light-collecting element on the light emitting element array side or in the vicinity thereof.

With the above structure, in the image display device, the light beam obtained by combining all the light from the light emitting element array has the smallest diameter at the position of the scanning element, and the area of the scanning element can be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic configuration diagram of an image display device according to Embodiment 1 of the present invention. Reference numeral 100 is a light source group, and 101a to 101n are red surface-emitting LEs.
D, 103a to 103n are green surface emitting LEDs, 10
5a to 105n are blue surface emitting LEDs, and
1, 103, and 105 are LEDs 101a to 1 respectively.
01n, LEDs 103a to 103n, LEDs 105a to
It is a light source in which 105n are arranged one-dimensionally at equal intervals. 1
Reference numeral 07 is a lens which is a condensing element, 109 is a galvanometer mirror which is a scanning element, and 110 is a display surface. Display surface 110 by moving galvanometer mirror 109
Above the scanning lines 111a-111a corresponding to the number of light emitting elements of three colors.
111n, 113a to 113n, and 115a to 115n are formed. The light sources 101, 103 and 105 are integrated in the same plane, and the scanning lines 111i, 113i and 11 are integrated.
L in each light source so that 5i (i corresponds to a to n) overlap
ED is arranged. In addition, the LEDs 101a to 101
Since n, 103a to 103n, and 105a to 105n are arranged at equal intervals, the scanning lines are also at equal intervals. In FIG. 1, the scanning lines are shown with a slight shift for the sake of clarity, but they actually overlap.

FIG. 2 shows the optical system of FIG.
(A) is a side view and (b) is a top view. Here, in order to make it easy to understand in terms of expression, the description is given in a state in which the light reflected by the galvanometer mirror 109 is transmitted.

The reflecting surface of the galvanometer mirror 109 is the focal plane (focal length f) of the lens 107 opposite to the light source group 100.
It is arranged to be located in. In addition, the light source group 100
And the display surface 110 via the galvanometer mirror 109 are arranged so as to be in an image forming relationship with the lens 107.

The size required for the lens 107 is L
Since it may be long in the direction in which the EDs are arranged and short in the direction orthogonal thereto, it is processed into a rectangular shape.

By using such an optical system, LE
D101a to 101n, 103a to 103n, 105a
The light beam obtained by combining all the light beams from to 105n has the smallest diameter at the position of the galvanometer mirror 109, and the area of the galvanometer mirror 109 can be reduced. As a result, it is possible to drive at high speed and with low power consumption. Each LED 101a-101
The light beams from n, 103a to 103n, and 105a to 105n have substantially the same beam diameter at the position of the galvanometer mirror 109, so that the light utilization efficiency for each LED can be made substantially equal. Therefore, no special device is required to make the brightness of the image equal in the central part and in the upper and lower parts, and the light output from the central LED of the light source and the peripheral LED can be made uniform. Is improved.

Three scanning lines (for example, 111i, 113)
i, 115i) are laterally offset and overlapped corresponding to the distance between the light sources. Therefore, the LED may be driven with a time lag considering this lag. The effective area of the image is 117.

(Example Based on Embodiment 1) Light Source 101
As a red surface-emitting LED with 100 μm at 80 μm intervals
The one-dimensionally integrated one is used as the light source 103,
One of 100 green surface-emitting LEDs integrated at 80 μm intervals in a one-dimensional form is used as the light source 105, and 100 blue one-dimensional surface emitting LEDs integrated at 80 μm intervals in a one-dimensional form are used. . Furthermore, the distance between each light source is 1m
As m, the light source group 100 is formed by aligning and integrating the scanning lines so as to overlap each other on the display surface. As a result, the light source group 100 has a size of about 8 mm × 2 mm. The lens 107 is a single lens with a focal length of 24 mm.
What was processed into a rectangular shape of mm × 20 mm is used. The galvanometer mirror 109 is a mirror formed by mechanical assembly, is arranged at the position of the focal plane of the lens 107, and is saw-tooth driven at a scanning frequency of 60 Hz. The area of the mirror is a 6 mm square. Also, the magnification of the optical system is 10
The distance between the light source group 100 and the lens 107 is set so as to double. By using such an optical element, LE
Including the drive circuit of D and the drive mechanism of the galvanometer mirror,
It becomes possible to house the light source, the lens, and the galvanometer mirror in a housing of about 7 × 5 × 3 cm.

The variation in the utilization efficiency of the optical system can be suppressed to 4% or less in the central portion and the peripheral portion of the light source, and the LED array cut out from the same substrate is used without special measures for output correction. You can When the area of the mirror is reduced, the utilization efficiency itself decreases, but L
There is almost no variation in utilization efficiency between EDs. Therefore,
When the output of the LED is sufficient, the area of the mirror can be further reduced to further reduce the power consumption.

When the deflection angle of the galvanometer mirror 109 is about 9 degrees (the scanning angle of the reflected light is ± 18 degrees) and the modulation frequency of each LED is about 1 KHz, the display surface 110 shows
A color image of vertical 8 cm and horizontal 12 cm (resolution vertical 100 pixels, horizontal 160 pixels) is displayed, and it is possible to display an image that does not require character information or high resolution. The horizontal width of the image is determined by the scanning angle of the mirror, and the width can be increased by using a mirror having a large scanning angle. The lateral resolution is determined by the modulation frequency of the LED, and higher resolution can be achieved by increasing the modulation frequency. Further, by increasing the number of LED arrays, the number of pixels in the vertical direction can be increased. The image size can be increased by increasing the magnification of the optical system.

In this embodiment, a surface emitting laser array may be used as the light source. Further, the light emitting elements in the light source may be arranged in a zigzag in a two-row configuration. In the case of staggered arrangement, the length of the array light source can be halved, and the sizes of the lenses and mirrors can be reduced accordingly, which is effective for further size reduction.

Further, the scanning element may be a resonant mirror whose main body is Si formed by a semiconductor process. In this case, further miniaturization is possible. Since a relatively high scanning frequency of 1 kHz or higher is more convenient for this type of mirror in view of the characteristics of the mirror, the modulation frequency of the light emitting element may be controlled accordingly.

In addition, it is possible to use a rotating polygon mirror as the scanning element.

Further, although a single lens is used as the condensing element, it may be composed of a plurality of lens groups, and may be a convex mirror or a concave mirror having a predetermined curvature.

As the display surface, a dedicated screen may be used, or it may be displayed on a wall or ceiling.

(Second Embodiment) FIG. 3 is a schematic configuration diagram of an image display device according to a second embodiment of the present invention. In this figure, unlike FIG. 1, a projection optical system is configured by a collimator lens 207 and a condenser lens 209 provided before and after the galvanometer mirror 109. Others are the same as those in FIG. 1, and the same members are denoted by the same reference numerals. 211a-211
n, 213a to 213n, 215a to 215n are LEDs
101a-101n, 103a-103n, 105a-
This is a scanning line corresponding to 105n.

FIG. 4 shows the optical system of FIG.
(A) is a side view and (b) is a top view. Here, in order to make it easy to understand in terms of expression, the description is given in a state in which the light reflected by the galvanometer mirror 109 is transmitted.

The reflecting surface of the galvano mirror 109 is arranged so as to be located on the focal plane (focal length f) of the collimator lens 207 opposite to the light source group 100. The light source group 100 is arranged so as to be located on the focal plane of the collimator lens 207 on the light source side. As a result, each LED
The light from the galvano mirrors 10 is parallel light.
Irradiated to 9. Further, the light scanned by the galvanometer mirror is condensed on the display surface 110 by the condenser lens 209, and the scanning lines 211a to 211n, 213a to 21l.
3n, 215a to 215n are formed.

Similar to the first embodiment, the three scanning lines (for example, 211i, 213i, 215i) are laterally shifted and overlapped in correspondence with the distance between the light sources. Therefore, the LED may be driven with a time lag considering this lag. The effective area of the image is 217.

In the first embodiment, the position where the scanned light beam is focused is slightly different between the central part and the peripheral part due to the field curvature aberration, and the central part is focused farther (FIG. 2).
Therefore, the image quality of the image slightly deteriorates on the display surface. Further, assuming that the scanning angle when the center is 0 is θ, the position of the beam on the display surface is determined by tan θ. Therefore, when the galvanometer mirror 109 is moving at a constant angular velocity, the LED in the central portion and the peripheral portion are It is necessary to change the modulation frequency of. On the other hand, in the present embodiment, the condenser lens 20
This can be solved by using an f-θ lens for 9 or an aberration correction lens, so that it is possible to improve the controllability during the modulation of the LED and the image quality.

In this embodiment, the condenser lens 209 may be composed of a plurality of lens groups, and may be a convex mirror or a concave mirror having a predetermined curvature. Further, similar to the first embodiment, the light emitting element and the scanning element can take various forms.

Further, in the present embodiment, the light from the LED is collimated by using the collimator lens 207, but it may not be collimated. For example, in an optical system as shown in FIG. 1 (FIG. 2), a condensing lens as in this embodiment may be added to the display surface side of the galvano mirror 109.

(Third Embodiment) FIG. 5 is a schematic configuration diagram of a light source group in an image display device according to a third embodiment of the present invention.

In FIG. 5, 301-1 is a red surface emitting LED, 303-1 is a green surface emitting LED, 305
-1 is a blue surface emitting LED. Also, 301, 3
03 and 305 are surface emitting LEDs 301-
It is a light source in which 1, 303-1, 305-1 are arranged two-dimensionally. Reference numeral 300 denotes a light source group in which these light sources are integrated on the same surface. The configuration other than the light source is the same as that in FIG. 1, and the details are omitted. In each light source, the plurality of LEDs are two-dimensionally arranged at a predetermined pitch so that the scanning lines formed on the display surface are arranged at equal intervals. Further, between the light sources, the scanning lines by the LEDs at the same position in the light sources are arranged so as to overlap on the display surface. When driving each LED, the modulation signal may be given to each LED by shifting the time corresponding to the lateral shift of the scanning line.

In the present embodiment, it is possible to easily increase the number of light emitting elements, that is, the number of scanning lines without changing the size of optical elements such as lenses, and it is possible to display a high resolution image. Become.

(Example Based on Embodiment 3) Light Source 301
As a red surface-emitting LED vertically at an interval of 80 μm
00 pieces, 6 pieces at intervals of 80 μm horizontally, totaling 600 pieces in a two-dimensional form (8 mm × 0.48 m in total)
m) is used. The scanning lines are arranged at a slight angle in the lateral direction, so that the scanning lines are evenly spaced.

With the same arrangement, the green light source 303 and the blue light source 305 are formed. The light sources are adjacently integrated with each other to form a light source group 300. The size of the light source group is 8 mm x 1.5
mm. Such a light source group 300 is applied to the optical system of FIG. The size of the light source 301 is almost the same as that of the light source 101 used in the example based on the first embodiment, and the lens 107 and the galvano mirror 109 may have the same size as the example based on the first embodiment. , 7 ×
It becomes possible to house the light source, the lens, and the galvanometer mirror in a housing of about 5 × 3 cm.

The deflection angle of the galvanometer mirror 109 is ± 9 degrees (the scanning angle of the reflected light is ± 18 degrees), the modulation frequency of each LED is about 5 KHz, and the magnification of the projection optical system is 30 times. When each optical element is arranged on the display surface 110,
An image with a height of 24 cm and a width of 30 cm (resolution 600
Pixels, horizontal 800 pixels) can be displayed.

In this embodiment, L in the light source group 300 is
The method of arranging the EDs is not limited to this, and the LED arrays are vertically displaced so that the scanning lines are arranged at equal intervals in the light source, and the scanning lines are arranged so as to overlap between the light sources. Anything will do.

In the above-described embodiments, three color LED arrays are used as the plurality of light sources, but a plurality of light sources composed of LED arrays of the same color may be integrated to form a light source group. According to this, it is possible to improve the screen brightness when the amount of light of the single LED is not sufficient for the purpose of displaying a monochrome image.

[0047]

As described above, according to the present invention,
By forming an LED array of three colors on the same surface and optimally arranging the optical elements, it is possible to display a color image suitable for downsizing with high productivity, low power consumption, little color unevenness. An image display device can be provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image display device of a first embodiment according to the present invention.

FIG. 2 is a schematic configuration diagram of an optical system of the image display device of the first embodiment.

FIG. 3 is a schematic configuration diagram of an image display device according to a second embodiment.

FIG. 4 is a schematic configuration diagram of an optical system of the image display device of the second embodiment.

FIG. 5 is a schematic configuration diagram of a light source according to a third embodiment.

FIG. 6 is a schematic configuration diagram of a conventional image display device.

FIG. 7 is a schematic configuration diagram of another conventional image display device.

FIG. 8 is a schematic configuration diagram of still another conventional image display device.

[Explanation of symbols]

100,300 light source group 101,103,105,301,303,305 light source 101a-101n, 301-1 red surface emitting LED 103a-103n, 303-1 green surface emitting LED 105a-105n, 305-1 blue Surface emitting LED 107 Lens 109 Galvano mirror 110 Display surfaces 111a to 111n, 113a to 113n, 115a to
115n, 211a to 211n, 213a to 213n, 215a to
215n scanning line 207 collimating lens 209 condensing lens 117, 217 image area

Claims (14)

[Claims] 1. A light source group having a plurality of light sources composed of the same number of light emitting elements as the number of scanning lines of an image, a scanning element which reflects a plurality of light beams from the light source group and scans in one direction, Each of the scanning lines formed by the light beam from each light source is provided with a projection optical system that forms a plurality of scanning lines by condensing the plurality of light beams on the display surface.
The light emitting element in each light source is arranged so that the scanning lines formed by the light beams at the corresponding positions from the other light sources constituting the light source group overlap each other. 2. The image display device according to claim 1, wherein each of the light sources is composed of a plurality of light emitting elements of substantially the same color. 3. The light source group includes at least a light source including a red light emitting element, a light source including a green light emitting element, and a light source including a blue light emitting element. The image display device according to claim 1. 4. The image display device according to claim 1, wherein each of the light sources forming the light source group is composed of light emitting elements having substantially the same color. 5. The image display device according to claim 1, wherein the light source is a surface emitting laser array or a surface emitting LED array. 6. The image display device according to claim 1, wherein the light sources forming the light source group are integrated in the same plane. 7. The light emitting elements forming the light source are arranged in a one-dimensional or two-dimensional manner so that the intervals of the scanning lines on the display surface are constant. 7. The image display device according to any one of to 6. 8. The projection optical system has a first condensing element provided between the light source group and a scanning element, and a focal plane on the scanning element side of the first condensing element, Alternatively, the image display device according to any one of claims 1 to 7, wherein a reflective surface of the scanning element is provided in the vicinity thereof. 9. The image according to claim 1, wherein the projection optical system further includes a second light-collecting element provided between the scanning element and the display surface. Display device. 10. The light source group is provided on or near a focal plane of the first condensing element on the light emitting element array side. Image display device. 11. The image display device according to claim 1, wherein the scanning element is a galvanometer mirror or a rotating polygon mirror. 12. The image display device according to claim 1, wherein the scanning element is formed by a semiconductor process. 13. The image display device according to claim 11, wherein the galvano mirror is formed by mechanical assembly. 14. The first and second light-collecting elements are each composed of a single lens, a plurality of lenses, or a mirror having a predetermined curvature, according to any one of claims 1 to 13. The image display device described.