JP2007121539A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device that can display a large high-quality image by scanning with a light beam. <P>SOLUTION: The image display device 100 displays an image by scanning an irradiation objective surface S with a beam light modulated according to image signals. The device is equipped with: a plurality of light source units 101R, 101G, 101B for supplying beam light in which at least either peak wavelengths or beam qualities are different from one another; and a scanning unit 200 for scanning the beam light from the light source units 101R, 101G, 101B. The light source units 101R, 101G, 101B are disposed in such a manner that at least either the peak wavelengths or beam qualities are taken into consideration and the respective optical paths from the light source units 101R, 101G, 101B to the irradiation objective surface S are made shorter with the larger values of the peak wavelengths or beam qualities. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an image display apparatus, and more particularly to a technique of an image display apparatus that displays an image by scanning a light beam modulated in accordance with an image signal.

In recent years, a laser projector that displays an image by scanning laser light has been proposed as an image display device that displays an image. Laser light has features such as high color purity, high coherence, and easy shaping. Therefore, it is expected that a laser projector displays an image with high resolution and good color reproducibility. For example, Patent Document 1 proposes a technique for displaying an image by scanning each of red, blue, and green laser beams.

JP-A-1-245780

In recent years, there has been an increasing demand for larger screens for image display devices. The larger the image displayed by scanning with laser light, the longer the optical path between the light source unit and the irradiated surface. For example, in the case of a projector having a 50-inch screen, the optical path between the light source unit and the screen is 1 to 2 m. In the case of using a plurality of laser beams having different degrees of beam diameter depending on the length of the optical path, the longer the optical path between the light source unit and the irradiated surface, the more the deviation of the beam diameter on the irradiated surface becomes. growing. Deviations in the beam diameter on the irradiated surface cause color misregistration and blurring. As described above, even when a large image is displayed using the conventional technology as it is, it is difficult to obtain a high-quality image with reduced color shift and blur. The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an image display device capable of displaying a large and high-quality image by scanning light beams.

In order to solve the above-described problems and achieve the object, according to the present invention, there is provided an image display device that displays an image by scanning a surface to be irradiated with a light beam modulated in accordance with an image signal. A plurality of light source units that supply light beams having different peak wavelengths and beam qualities, and a scanning unit that scans the light beams from the light source units. The light source units include the peak wavelength and the beam quality. It is possible to provide an image display device characterized in that the optical path from the light source unit to the irradiated surface is shortened as the value is increased.

For example, it is known that the degree of increase in the beam diameter of laser light, which is beam light, varies depending on the peak wavelength and the beam quality. If the laser path has the same optical path length,
The larger the peak wavelength and the larger the beam quality, the larger the characteristic. The beam quality represents a ratio obtained by dividing an actual beam light divergence angle by an ideal diffraction limited beam divergence angle. The beam quality is expressed by a numerical value of 1 or more. According to the present invention, the arrangement of the light source units can be optimized so that the beam diameters of the respective light beams on the irradiated surface are substantially equal. When the optical path between the light source unit and the illuminated surface is long, by reducing the deviation of the beam diameter on the illuminated surface, a high-quality image that is large and has reduced color deviation and blurring Can be displayed. Furthermore, an image can be displayed with high resolution by adopting a configuration in which the spot of each light beam is contained in the pixel region. As the image display device is larger, the degree of freedom of the position where each light source unit is provided is increased. Therefore, it is possible to easily determine the arrangement of each light source unit so that the spot fits in the pixel region. As a result, an image display device capable of displaying a large and high-quality image by scanning with the light beam can be obtained.

According to a preferred aspect of the present invention, it is desirable that the light source unit be arranged so that the optical path from the light source unit to the irradiated surface becomes shorter as the product of the peak wavelength and the beam quality is larger.
Since the change rate of the beam diameter with respect to the change rate of the peak wavelength and the change rate of the beam diameter with respect to the change rate of the beam quality are both the same, the arrangement of each light source unit is determined using the product of the peak wavelength and the beam quality as an index. Can be determined. Thereby, the arrangement of the light source units can be determined in consideration of the beam diameter expansion due to the influence of the peak wavelength and the beam quality.

Moreover, as a preferable aspect of the present invention, it is desirable to have a condensing optical system that condenses the beam light. Thereby, even when the optical path between the light source unit and the irradiated surface is long, the spot of each light beam can be stored in the pixel region, and a large and high-resolution image can be displayed. In addition, the spot diameter in the scanning unit can be reduced, and the size of the reflection mirror used in the scanning unit can be reduced. By making the reflection mirror compact,
The reflection mirror can be vibrated at a high speed and with a large deflection angle.

According to a preferred aspect of the present invention, it is desirable that the scanning unit includes a reflection mirror that reflects the beam light, and the beam light is scanned by causing the reflection mirror to resonate. By causing the reflecting mirror to resonate, the amount of displacement of the reflecting mirror can be increased. Thereby, the laser beam can be efficiently scanned with a small amount of energy. In the present invention, it is possible to place a spot in the pixel region and reduce the beam diameter at the position of the reflection mirror. For this reason, it is possible to use a reflection mirror that is small and can be resonated.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of an image display apparatus 100 according to Embodiment 1 of the present invention. The image display device 100 is a so-called rear projector that supplies laser light to one surface of the screen 110 and observes an image by observing light emitted from the other surface of the screen 110. The image display apparatus 100 displays an image by causing the light beam modulated according to the image signal to scan on the irradiated surface S of the screen 110.

The image display apparatus 100 includes an R light source unit 101R, a G light source unit 101G, and a B light source unit 101B. The R light source unit 101R is a semiconductor laser that supplies red laser light (hereinafter referred to as “R light”) that is beam light. The G light source unit 101G is a semiconductor laser that supplies green laser light (hereinafter referred to as “G light”), which is beam light. The light source unit 101B for B light is a semiconductor laser that supplies blue laser light (hereinafter referred to as “B light”) that is beam light. Each of the color light source units 101R, 101G, and 101B supplies laser light that is modulated according to an image signal and has different peak wavelengths. As the modulation according to the image signal, either amplitude modulation or pulse width modulation may be used.

The condensing optical system LN includes an R light source unit 101R and a first dichroic mirror 103R, a G light source unit 101G and a second dichroic mirror 103G, and a B light source unit 10.
1B and the mirror 103B are provided respectively. Thus, the condensing optical system LN is provided for each color light. The condensing optical system LN condenses each laser beam. Each of the condensing optical systems LN is configured to have substantially the same focal length. The condensing optical system LN is not limited to being configured by a single lens, and may be configured by a plurality of lenses.

The first dichroic mirror 103R reflects R light and transmits G light and B light. The second dichroic mirror 103G reflects G light and transmits B light. Mirror 103B
Reflects B light. The R light from the R light source 101R is emitted from the first dichroic mirror 1
The light path is bent by approximately 90 degrees by reflection at 03R, and then proceeds toward the scanning unit 200. The G light from the G light source unit 101G is reflected by the second dichroic mirror 103G so that the optical path is bent by approximately 90 degrees and transmitted through the first dichroic mirror 103R.
It proceeds in the direction of the scanning unit 200. The B light from the B light source unit 101B is reflected by the mirror 103B so that the optical path is bent by approximately 90 degrees, passes through the second dichroic mirror 103G and the first dichroic mirror 103R, and then toward the scanning unit 200. proceed. In this way, R light, G light, and B light are combined.

FIG. 2 shows a schematic configuration of the scanning unit 200. The scanning unit 200 has a so-called double gimbal structure having a reflection mirror 202 and an outer frame portion 204 provided around the reflection mirror 202. The outer frame portion 204 is connected to a fixed portion (not shown) by a first torsion spring 206 that is a rotation shaft. The outer frame portion 204 rotates around the first torsion spring 206 by utilizing the twist of the first torsion spring 206 and the restoration to the original state. The reflection mirror 202 is a second torsion spring 2 that is a rotation axis substantially orthogonal to the first torsion spring 206.
07 is connected to the outer frame portion 204. The reflection mirror 202 is a light source unit 1 for each color light.
The laser beams from 01R, 101G, and 101B are reflected. The reflection mirror 202 can be configured by forming a highly reflective member, for example, a metal thin film such as aluminum or silver. The reflection mirror 202 has a square shape, for example.

The reflecting mirror 202 is displaced so that the laser beam is scanned in the Y direction (see FIG. 1) on the screen 110 when the outer frame portion 204 rotates about the first torsion spring 206. In addition, the reflection mirror 202 rotates around the second torsion spring 207 using the twist of the second torsion spring 207 and the restoration to the original state. Reflective mirror 2
02 is rotated around the second torsion spring 207, thereby reflecting the mirror 202.
The laser beam reflected by is displaced so as to scan in the X direction. Thus, the scanning unit 200
Laser light from each color light source unit 101R, 101G, 101B is repeatedly scanned in the X and Y directions.

FIG. 3 illustrates a configuration for driving the scanning unit 200. Reflection mirror 20
When the side 2 reflects the laser beam is the front side, the first electrodes 301 and 302 are formed of the outer frame portion 204.
Are provided at substantially symmetrical positions with respect to the first torsion spring 206. When a voltage is applied to the first electrodes 301 and 302, the first electrodes 301 and 302,
A predetermined force corresponding to the potential difference, for example, an electrostatic force, is generated between the outer frame portion 204 and the outer frame portion 204. Outer frame 2
04 rotates about the first torsion spring 206 by alternately applying a voltage to the first electrodes 301 and 302.

Specifically, the second torsion spring 207 includes a third torsion spring 307 and a fourth torsion spring 308. Third torsion spring 307 and fourth torsion spring 308
A mirror-side electrode 305 is provided between the two. A second electrode 306 is provided in the space behind the mirror side electrode 305. When a voltage is applied to the second electrode 306, the second electrode 3
A predetermined force corresponding to the potential difference, for example, an electrostatic force, is generated between 06 and the mirror side electrode 305. When a voltage having the same phase is applied to any of the second electrodes 306, the reflection mirror 202 is
It rotates around the torsion spring 207. The scanning unit 200 rotates the reflection mirror 202 in this way, thereby scanning the laser light in the two-dimensional direction. The scanning unit 200 can be created by, for example, MEMS (Micro Electro Mechanical Systems) technology.

For example, the scanning unit 200 moves 1 in the Y direction, which is the sub-scanning direction, in one frame period of the image.
While scanning the laser beam twice, the reflection mirror 202 is displaced so as to reciprocate the laser beam a plurality of times in the X direction which is the main scanning direction. Assuming that the X direction is the first direction and the Y direction is the second direction substantially orthogonal to the first direction, the scanning unit 200 has a frequency at which the laser beam is scanned in the first direction. Driven to be higher than the frequency of scanning light. In order to scan the laser beam in the X direction at high speed, it is desirable that the scanning unit 200 be configured to resonate the reflecting mirror 202 around the second torsion spring 207. By causing the reflection mirror 202 to resonate, the amount of displacement of the reflection mirror 202 can be increased. By increasing the amount of displacement of the reflection mirror 202, the scanning unit 200 can efficiently scan the laser beam with less energy. The reflection mirror 202 is
It may be driven by an operation other than the resonance operation.

The scanning unit 200 is not limited to the configuration driven by the electrostatic force corresponding to the potential difference. For example,
A configuration in which the piezoelectric element is driven by using an expansion / contraction force or electromagnetic force may be used. The scanning unit 200 may include a reflection mirror that scans the laser light in the X direction and a reflection mirror that scans the laser light in the Y direction. Furthermore, the scanning unit 200 is not limited to a configuration using a galvanometer mirror,
You may use the polygon mirror which rotates the rotary body which has a some mirror piece.

Returning to FIG. 1, the light from the scanning unit 200 enters the reflecting unit 105. The reflector 105 is
The laser beam from the scanning unit 200 is reflected in the direction of the screen 110. The screen 110 is provided on the front surface of the housing 107. The housing 107 seals the space inside the housing 107. The screen 110 is a transmissive screen that transmits laser light modulated in accordance with an image signal. The screen 110 includes, for example, a Fresnel lens that converts the angle of light toward the viewer, a lenticular lens that diffuses light (both not shown), and the like. The observer
The image is viewed by observing the light emitted from the screen 110.

FIG. 4 shows the spot SP of the laser beam formed on the irradiated surface S of the screen 110 and the pixel P displayed by scanning the laser beam. The pixel P has a square shape with a side length d. The spot SP has a circular shape with a radius ω _P. The radius ω _P is the beam radius of the laser light on the irradiated surface S. In this specification, the beam radius refers to a Gaussian beam radius. If the beam radius ω _P is equal to or less than d / 2, the spot SP can be contained in the region of the pixel P. The image display apparatus 100 can perform high-definition display according to the resolution by placing the spot SP in the region of the pixel P.

For example, 1920 × 1 in a screen 110 having a diagonal length of 50 inches
Consider the case of displaying a full high-definition image of 080 pixels. In this case, the length d of one side of one pixel P is approximately 0.577 mm. When the spot SP in which the laser light just fits in the region of the pixel P is formed, the beam radius ω _P of the laser light on the irradiated surface S is 0.577 / 2≈0.288 (mm).

5 and 6 show light sources for each color light 101R for displaying a high-quality image with high resolution.
, 101G, 101B will be described. Here, the R light source unit 10
The description will be made assuming that the positions of the light source portions 101R, 101G, and 101B for each color light are determined with reference to the position of 1R. As shown in FIG. 5, R from the R light source 101R
The light is condensed by the condensing optical system LN so as to form a beam waist BW at a position where the distance from the irradiated surface S is L ₁ . The beam waist BW is a position where the wavefront curvature is zero and the beam diameter is minimum in a Gaussian beam. In FIG. 5, for the sake of convenience, the R light source unit 1 is used.
The optical path from 01R to the screen 110 is illustrated as being on one straight line, and illustration of a configuration unnecessary for the description is omitted.

Beam radius ω (z) of Gaussian beam at a position z from the position of the beam waist BW
) Can be represented by the following formula (1).

Where λ is the wavelength of the light beam, M ² is the beam quality, and ω ₀ is the beam radius at the beam waist BW. The beam quality M ² represents a ratio obtained by dividing an actual beam light divergence angle by an ideal diffraction limited beam divergence angle. The beam quality M ² is represented by a numerical value of 1 or more. Here, it is assumed that the beam quality M ² = 1.0.

For example, consider the case where the distance L ₀ from the reflecting mirror 202 to the irradiated surface S is 1.5 m in the configuration shown in FIG. Further, the beam radius ω ₀ at the beam waist BW is set to 0.
The beam radius ω _P at the position of 284 mm and the irradiated surface S is 0.288 mm. Formula (1
), For R light having a peak wavelength λ = 650 nm, z = 46.312 mm when the beam radius ω ₀ = 0.284 mm at the beam waist BW extends to 0.288 mm.
And can be calculated. From this, the distance L ₁ = 46 from the irradiated surface S to the beam waist BW
. 312 mm can be obtained. The position of the R light source unit 101R can be determined by using the condensing optical system LN so that the beam waist BW is formed at a position 466.312 mm before the irradiated surface S. The beam diameter at the position of the reflection mirror 202 is
3. It can be calculated as 230 mm.

If the beam waist BW for G light is formed at the same position as the beam waist BW for R light, the beam diameter of G light on the irradiated surface S becomes smaller than the beam diameter of R light. Formula (1)
For the G light having the peak λ = 550 nm, the beam waist BW from the irradiated surface S is used.
Distance L ₁ = 54.732 mm. Therefore, the G light source 101
G is 54.732-46.312 = 8.420 (mm) longer than the distance from the light source unit 101R for R light to the irradiated surface S than the distance from the light source unit 101R for R light to the irradiated surface S. It will suffice if it is provided at such a position.

Here, the distance between the G light source 101G and the second dichroic mirror 103G and the distance between the R light source 101R and the first dichroic mirror 103R are substantially the same. G
As shown in FIG. 6, the light source 101G for light is arranged at a position shifted by a distance L ₂ = 8.420 mm from the R light source 101R in the opposite direction to the scanning unit 200.

If the beam waist BW for B light is formed at the same position as the beam waist BW for R light or G light, the beam diameter of B light on the irradiated surface S will be smaller than the beam diameter of R light or G light. Using equation (1), it is possible to obtain the distance L ₁ from the irradiated surface S to the beam waist BW = 66.895 mm for the B light having the peak λ = 450 nm. Therefore, in the B light source unit 101B, the distance from the B light source unit 101B to the irradiated surface S is 66.895-54.732 = the distance from the G light source unit 101G to the irradiated surface S = 12.163 (
mm) It should suffice if it is provided at a position that becomes longer.

Here, the distance between the B light source unit 101B and the mirror 103B and the distance between the G light source unit 101G and the second dichroic mirror 103G are substantially the same. B light source 101B
As shown in FIG. 6, the distance L from the G light source 101G in the direction opposite to the scanning unit 200 is
₃ = disposed at a position shifted by 12.163 mm. As described above, the beam radii ω _P of the respective color lights at the position of the irradiated surface S can all be 0.288 mm. Each of the light source units 101R, 101G, and 101B has a surface S to be irradiated as the peak wavelength increases.
It is arranged so that the optical path to is shorter.

As described above, the arrangement of the light source units 101R, 101G, and 101B can be optimized so that the beam diameters of the laser beams on the irradiated surface S are substantially equal. Light source unit 101R, 1
When the optical path between 01G and 101B and the surface S to be irradiated becomes long, by reducing the deviation of the beam diameter on the surface S to be irradiated, it is large and high quality with reduced color shift and blurring. Simple images can be displayed.

Further, the condensing optical system LN can be configured such that the spot SP of each laser beam is contained in the pixel region. By using the condensing optical system LN, a large and high-resolution image can be displayed. As the image display device is larger, the degree of freedom of the position where each light source unit is provided is increased. Therefore, the light source units 101R, 101G, and 10 are arranged so that the spot is within the pixel region.
The arrangement of 1B can be easily determined. In addition, the spot diameter in the reflection mirror 202 can be reduced, and the size of the reflection mirror 202 can be reduced. Since the reflecting mirror 202 can be made small, the reflecting mirror 202 can be vibrated at a high speed and with a large deflection angle. Thereby, there is an effect that a high-quality image can be displayed with a large size and a high resolution by scanning the light beam.

FIG. 7 illustrates an image display apparatus according to Embodiment 2 of the present invention. The image display apparatus according to the present embodiment is characterized in that the positions of a plurality of light source units having different beam qualities are optimized. The same parts as those of the image display apparatus 100 of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, the configuration for the G light will be described as a representative example, and the illustration and description of the configurations for the other color lights will be omitted. The five G light source sections 101G1-5 provided in the image display apparatus of the present embodiment have different beam qualities.
Supply light. The five G light source sections 101G1 to 5 have a peak wavelength of 55.
It is assumed that 0 nm G light is supplied.

The beam qualities M ² of the five G light source sections 101G1 to 101G5 are 2.0, 1.8,
It is assumed that they are 1.5, 1.3, and 1.0. A condensing optical system LN and a mirror 701 are provided in the optical path of the G light from each of the G light source units 101G1 to 101G5. The G light from each of the G light source sections 101G1 to 101G5 is reflected by the mirror 701 after passing through the condensing optical system LN, so that the optical path is bent by approximately 90 degrees. The G light reflected by the mirror 701 has an interval d of about 1 mm.
Is incident on the convex lens 702. The convex lens 702 collects the five G lights. The concave lens 703 collimates the G light from the convex lens 702. As described above, the five G lights are synthesized by the convex lens 702 and the concave lens 703. In addition, when it is possible to make five G lights incident on the reflection mirror 202 and the interval d can be reduced to some extent,
The convex lens 702 and the concave lens 703 may be omitted.

G-light source unit 101G1~5 the larger the beam quality M ^2, the illuminated surface S from the light source unit
It is arranged so that the optical path to is shorter. Here, the surface to be irradiated S is reflected from the reflecting mirror 202.
Consider a case in which the distance L ₀ (see FIG. 5) is 2.0 m. Beam West B
The beam radius omega ₀ in W 0.286mm, and 0.288mm beam radius omega _P at the position of the irradiated surface S. For the first G light source 101G1 having a beam quality M ² of 2.0, the distance L ₁ from the irradiated surface S to the beam waist BW is equal to 27.76 according to the equation (1).
7 mm can be obtained. The position of the first G light source unit 101G1 can be determined using the condensing optical system LN so that the beam waist BW is formed at a position 27.767 mm before the irradiated surface S. The beam diameter at the position of the reflection mirror 202 is
It can be calculated as 4.859 mm.

Next, a 2G-light source unit 101G2 beam quality M ² is 1.8, the formula (1
), The distance L ₁ from the irradiated surface S to the beam waist BW = 30.852 mm can be obtained. In the second G light source unit 101G2, the distance from the second G light source unit 101G2 to the irradiated surface S is 30.852-27.767 than the distance from the first G light source unit 101G1 to the irradiated surface S. = 3.085 (mm) It should just be provided in the position which becomes long. Here, if the optical path to the second G light source 101G2 and the mirror 701 is longer by d = 1 mm than the optical path to the first G light source 101G1 and the mirror 701, the second G
The light source unit 101G2 is disposed at a position shifted from the first G light source unit 101G1 by a distance L ₄ = 2.085 mm in the direction opposite to the scanning unit 200.

3G light source 101G3 and 4G with beam quality M ² of 1.5, 1.3 and 1.0
For the light source unit 101G4 and the fifth G light source unit 101G5, the distance L ₁ = 3, respectively.
It can be calculated as 7.023 mm, 42.718 mm, and 55.534 mm. The position where the third G light source unit 101G3 is shifted from the second G light source unit 101G2 by a distance L ₅ = 37.023-30.852-1 = 5.170 (mm) in the direction opposite to the scanning unit 200 Placed in. The fourth G light source 101G4 is changed from the third G light source 101G3 to the scanning unit 2.
Distance in the direction opposite to 00 L ₆ = 42.718-37.0023-1 = 4.695 (mm)
It is arranged at a shifted position. The fifth G light source unit 101G5 is a fourth G light source unit 1.
01G4 distance in the opposite direction to the scanning unit 200 from L ₇ = 55.534-42.718-1
= 11.816 (mm).

In this way, the arrangement of the G light source units 101G1 to 101G5 can be optimized so that the beam diameters of the laser beams on the irradiated surface S are substantially equal. Thereby, also in the case of the present embodiment, there is an effect that a high-quality image can be displayed with a large size and a high resolution by scanning of the light beam.

Next, an image display apparatus according to Embodiment 3 of the present invention will be described. The schematic configuration of the image display apparatus according to the present embodiment is the same as that of the image display apparatus 100 according to the first embodiment. The image display apparatus according to the present embodiment uses the light source units 101R and 101G for each color light based on the product of the peak wavelength and the beam quality.
, 101B is optimized. A duplicate description with the first embodiment is omitted. As shown in the table of FIG. 8, the R light source unit 101R supplies R light having a peak wavelength λ of 650 nm and a beam quality M ² of 1.0. The G light source unit 101G supplies G light having a peak wavelength λ of 550 nm and a beam quality M ² of 1.1. The B light source unit 101B supplies B light having a peak wavelength λ of 450 nm and a beam quality M ² of 1.5. Product lambda × M ² of the peak wavelength lambda and beam quality M ² is the R light 650
, 605 for G light and 675 for B light.

Here, the distance L ₀ from the reflecting mirror 202 to the illuminated surface S is 1.1 m (see FIG. 5).
Consider the case. Further, the beam radius ω ₀ at the beam waist BW is set to 0.271 m.
m, and the beam radius ω _P at the position of the irradiated surface S is 0.288 mm. From the equation (1), it is possible to obtain the distance L ₁ = 129.375 mm from the irradiated surface S to the beam waist BW for the R light having the peak wavelength λ = 650 nm and the beam quality M ² of 1.0. For G light having a peak wavelength λ = 550 nm and a beam quality M ² of 1.1, the distance L ₁ from the irradiated surface S to the beam waist BW = 138.998 mm can be obtained. G-light source unit 101G, as shown in FIG. 9, a distance from the R-light source unit 101R in the opposite direction to the scanning unit _{200 L 9 = 138.998-129.375 = 9.623 (} mm) Arranged at the shifted position.

For B light with a peak wavelength λ = 450 nm and a beam quality M ² of 1.5, the distance L ₁ from the irradiated surface S to the beam waist BW can be calculated as 124.583 mm. The light source unit B for B light has a distance L ₈ = 129 from the light source unit for R light 101R in the direction of the scanning unit 200.
. It is arranged at a position shifted by 375-124.583 = 4.792 (mm). Each light source unit 101R, 101G, 101B, the more the product lambda × M ² of the peak wavelength lambda and beam quality M ² is large, the light path from the light source portion to the irradiated surface S is arranged to be shorter.

First dichroic mirror 903B provided at a position facing the B light source 101B
Reflects B light and transmits R light and G light. The second dichroic mirror 903R provided at a position facing the R light source unit 101R reflects the R light and transmits the G light. G
A mirror 903G provided at a position facing the light source 101G for light reflects the G light. B
The B light from the light source unit 101R is reflected by the first dichroic mirror 903B so that the optical path is bent by approximately 90 degrees, and then proceeds toward the scanning unit 200. R light source 101
The R light from R is reflected by the second dichroic mirror 903R to bend the optical path by approximately 90 degrees, passes through the first dichroic mirror 903B, and then travels toward the scanning unit 200. The G light from the G light source unit 101G is reflected by the mirror 903G so that the optical path is bent by approximately 90 degrees, passes through the second dichroic mirror 903R and the first dichroic mirror 903B, and then toward the scanning unit 200. proceed. In this way, R light, G light, and B light are combined.

The equation (1), the beam radius omega change ratio of _P with respect to the change rate of the peak wavelength lambda, since the rate of change of the beam radius omega _P relative rate of change of beam quality M ² is the same both, the peak wavelength lambda and a beam the product lambda × M ² of the quality M ² as an index, the light source unit 101R, 101G,
The arrangement of 101B can be determined. As a result, the peak wavelength λ and the beam quality M ²
The arrangement of the light source units 101R, 101G, and 101B can be determined in consideration of the expansion of the beam diameter due to the influence of the above.

FIG. 10 shows a schematic configuration of an image display apparatus 1100 according to the fourth embodiment of the present invention. The image display device 1100 is a so-called front projection type projector that supplies laser light to a screen 1110 provided on the viewer side and observes an image by observing light reflected by the screen 1110. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The laser beam from the scanning unit 200 passes through the emission window 1106 and then is displayed on the screen 1.
110 is incident. Also in the case of this example, as in each of the above examples, the larger the at least one of the peak wavelength and the beam quality, the shorter the optical path from the light source unit to the irradiated surface,
Light source portions 101R, 101G, and 101B for each color light are arranged. Thereby, also in a present Example, a high quality image can be displayed with a large sized and high resolution.

In the above embodiment, each color light source unit uses a semiconductor laser. However, the present invention is not limited to this as long as it can supply beam-shaped light. For example, each color light source unit may be configured to use a solid laser, a liquid laser, or a gas laser.

As described above, the image display device according to the present invention is suitable for displaying an image by scanning a plurality of light beams modulated in accordance with an image signal.

1 is a diagram illustrating a schematic configuration of an image display apparatus according to Embodiment 1 of the present invention. The figure which shows schematic structure of a scanning part. The figure explaining the structure for driving a scanning part. The figure which shows the spot and pixel in a to-be-irradiated surface. The figure explaining the position of the light source part for R light. The figure explaining the position of the light source part for each color light. FIG. 6 is a diagram illustrating an image display device according to a second embodiment of the invention. The figure which shows the example of a peak wavelength and beam quality. The figure explaining the position of the light source part for each color light. FIG. 10 is a diagram illustrating a schematic configuration of an image display device according to a fourth embodiment of the invention.

Explanation of symbols

100 image display device, 101R R light source unit, 101G G light source unit, 101B
B light source unit, 103R first dichroic mirror, 103G second dichroic mirror, 103B mirror, 105 reflector, 107 housing, 110 screen, 20
0 scanning section, LN condensing optical system, S irradiated surface, 202 reflecting mirror, 204 outer frame section,
206 1st torsion spring, 207 2nd torsion spring, 301, 302 1st electrode, 305 mirror side electrode, 306 2nd electrode, 307 3rd torsion spring, 308 4th torsion spring, SP spot, P pixel, BW beam waist , 101G1-5
G light source unit, 701 mirror, 702 convex lens, 703 concave lens, 903B first dichroic mirror, 903R second dichroic mirror, 903G mirror, 1
100 image display device, 1106 exit window, 1110 screen

Claims (4)

An image display device that displays an image by scanning a surface to be irradiated with beam light modulated according to an image signal,
A plurality of light source units for supplying the light beams having different peak wavelengths and at least one of beam qualities;
A scanning unit that scans the beam light from the light source unit,
The light source unit focuses on at least one of the peak wavelength and the beam quality, and is arranged such that the larger the value, the shorter the optical path from the light source unit to the irradiated surface. Image display device. 2. The image according to claim 1, wherein the light source unit is arranged such that an optical path from the light source unit to the irradiated surface becomes shorter as a product of the peak wavelength and the beam quality is larger. Display device. The image display apparatus according to claim 1, further comprising a condensing optical system that condenses the beam light. 4. The scanning unit according to claim 1, wherein the scanning unit includes a reflection mirror that reflects the beam light, and causes the beam light to scan by causing the reflection mirror to perform a resonance operation. 5. Image display device.

Images