Light source device and image display device

Abstract

To provide a light source device that can correct the color temperature of a color image displayed by an image display device.SOLUTION: A light source device causes a light emitting device to emit excitation light and determines the emitted excitation light as an excitation light beam, condenses the light on a wavelength conversion member 2 through a dichroic mirror DM and first condensation optical systems L3, L4, condenses reflected excitation light and fluorescent light generated in the wavelength conversion member 2 on an incident surface of a light homogenizing element 4 through the first and second condensation optical systems L3, L4, L5, and can adjust a condensation position of reflected excitation light LER and a condensation position of fluorescent light LF on the incident surface of the light homogenizing element 4 through adjustment of at least one of the position and posture of the dichroic mirror DM.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light source device and an image display device. [Background technology]

[0002] As a light source for image display devices such as projectors, head-up displays, and wearable displays, a light source device is known that irradiates a fluorescent layer with light emitted from a semiconductor laser (LD) or a light-emitting diode (LED) as excitation light to cause fluorescence to be emitted, and displays a color image using the excitation light and fluorescence (Patent Document 1).

[0003] In such light source devices, light of the three primary colors is combined in a time-division manner to display a color image, but if the relative positions of the optical elements that make up the light source device deviate from the designed relative positions, the color temperature of the displayed color image changes, causing the color image to become, for example, bluish or reddish, resulting in a ``color shift'' that impairs the image quality of the displayed color image. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a novel light source device that can correct the change in color tone. [Means for solving the problem]

[0005] The light source device of the present invention includes an excitation light source section that emits excitation light from one or more light-emitting elements and converts the emitted excitation light into an excitation light flux; a wavelength conversion member having a reflecting section that is irradiated with the excitation light flux and reflects the excitation light flux; a dichroic mirror that transmits either the excitation light flux or the fluorescence and reflects the other; a first focusing optical system that focuses the excitation light flux that has passed through the dichroic mirror onto the wavelength conversion member; a second focusing optical system that focuses the reflected excitation light and the fluorescence from the wavelength conversion member via the first focusing optical system; and a reflection optical system that reflects the reflected excitation light and the fluorescence focused by the second focusing optical system. and a light homogenizing element that homogenizes the fluorescence, wherein the excitation light beam incident on the wavelength conversion member passes through one half of the optically effective surface of the first focusing optical system, and the reflected excitation light is transmitted through the opposite half of the optically effective surface of the first focusing optical system via the optical axis of the optically effective surface, and the second focusing optical system shares the optical axis with the first focusing optical system, and the focusing position of the reflected excitation light and the focusing position of the fluorescence at the incident position of the light homogenizing element can be adjusted by adjusting at least one of the position and attitude of an optical element on the optical path of the excitation light in the excitation light light source unit, the dichroic mirror, and the wavelength conversion member. [Effects of the Invention]

[0006] According to this invention, regardless of deviations from the designed positional relationship between the optical elements that make up the light source device, changes in the color tone of the displayed color image can be corrected, making it possible to display a color image with an appropriate color temperature. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a basic configuration of a light source device. [Figure 2] 10A and 10B are diagrams illustrating the separation of the focusing position of the fluorescence and the focusing position of the reflected excitation light on the incident surface of the light homogenizing element due to the inclination of the wavelength conversion member from the normal position. [Figure 3]1 is a diagram illustrating an embodiment of a light source device. [Figure 4] 10A and 10B are diagrams illustrating another embodiment of a light source device. [Figure 5] 10A and 10B are diagrams illustrating still another embodiment of a light source device. [Figure 6] 10A and 10B are diagrams illustrating another embodiment of a light source device. [Figure 7] FIG. 10 is a diagram illustrating an embodiment in which two light source devices are used. [Figure 8] FIG. 1 is a diagram illustrating a projector as an image display device. [Figure 9] FIG. 1 is a diagram illustrating an example of a wearable display device as an image display device. [Figure 10] FIG. 10 is a diagram illustrating another example of a wearable display device as an image display device. [Figure 11] FIG. 10 is a diagram illustrating another example of a wearable display device as an image display device. [Figure 12] FIG. 10 is a diagram illustrating yet another example of a wearable display device as an image display device. [Figure 13] FIG. 1 is a diagram illustrating a head-up display device as an image display device. [Figure 14] 10A and 10B are diagrams illustrating another example of a head-up display device as an image display device. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment will be described below. First, an example of the basic configuration of a light source device will be described with reference to FIG. FIG. 1(a) shows an example of the basic configuration of a light source device. In Figure 1(a), reference symbols 1a and 1b denote light-emitting elements, and reference symbols 2a and 2b denote condenser lenses. The light-emitting elements 2a and 2b are semiconductor lasers (LDs) or light-emitting diodes (LEDs), and emit excitation light. In this example, the excitation light is "blue light."

[0009] The condenser lenses 2a and 2b are microlenses that collimate the blue light from the corresponding light-emitting elements. The excitation light that passes through the microlenses 2a and 2b passes through lenses L1 and L2 and enters the beam profiler PR, where it becomes an excitation light beam LE.

[0010] To add a bit more, although two light-emitting elements 1a and 1b are shown in FIG. 1(a), the number of light-emitting elements is not limited to two. The number of light-emitting elements can be one, or three or more. The number of light-emitting elements is determined appropriately depending on the color image to be displayed. For example, if the image display device that displays a color image is a large-screen projector, an array of a corresponding number of light-emitting elements will be required, but if the image display device is a wearable display, which will be described later, one light-emitting element may be sufficient. As described above, the excitation light that has passed through the microlenses 2a and 2b passes through the lenses L1 and L2, and the light beams are combined and pass through the beam profiler PR to become the excitation light beam LE.

[0011] The beam profiler PR is composed of, for example, a "microlens array in which rectangular aperture microlenses are arranged two-dimensionally," and adjusts the shape of the excitation light beam in a form similar to the rectangular aspect ratio of the microlens. The beam profiler PR is not essential, and the excitation light source unit can be configured without a beam profiler.

[0012] In this example, the light-emitting elements 1a and 1b, the microlenses 2a and 2b, the lenses L1 and L2, and the beam profiler PR constitute an excitation light source unit that causes a plurality of light-emitting elements to emit excitation light and converts the emitted excitation light into an excitation luminous flux LE.

[0013] The excitation light emitted from the lens L2 and having its cross-sectional shape adjusted by the beam profiler PR becomes an excitation light beam LE, which is incident on the dichroic mirror DM. The dichroic mirror DM has the function of transmitting one of the excitation light beam LE and the fluorescence light LF (described later) and reflecting the other. In the example being described, the dichroic mirror DM has the function of reflecting the excitation light beam LE and transmitting the fluorescence light LF.

[0014] The excitation light beam LE reflected by the dichroic mirror DM enters the lens L3, then enters the lens L4 which, together with the lens L3, forms the "first focusing optical system", and is focused at the focusing position P on the wavelength conversion member 2 to form a "focusing spot". In the example being described, the shape of the focused spot is adjusted to a shape similar to that of the microlens of the beam profiler PR by the action of the beam profiler PR.

[0015] In FIG. 1(a), the symbol AX indicates the optical axis of the first light-collecting optical system formed by the lenses L3 and L4. In this example, the wavelength conversion member 2 is a disk-shaped member called a “phosphor wheel”, and will be referred to as the phosphor wheel 2 hereinafter.

[0016] Further, reference numeral 3 denotes a “color separation means.” As will be described later, the color separation means 3 is disk-shaped, and will be referred to as a “color wheel 3” hereinafter.

[0017] 1(b) shows the surface of the phosphor wheel 2 on which the excitation light beam is collected (hereinafter referred to as the "incident side surface"). As shown in the figure, the phosphor wheel 2 is disk-shaped and can rotate around a rotation axis 2AX.

[0018] The focusing position P of the focusing spot of the excitation light beam LE is the position of the intersection of the optical axis AX and the incident side surface. The incident side of the phosphor wheel 2 is divided into two sectorial regions 2B and 2Y around the rotation axis 2AX. The sectorial region 2B, with an opening angle of 120 degrees, is the "reflective section," and the excitation light beam LE that converges on this region is reflected. Hereinafter, the sectorial region 2B will also be referred to as the "reflective region 2B."

[0019] The sectoral region 2Y has an opening angle of 240 degrees, and a "fluorescent layer" is formed in this region. In other words, the sectoral region 2Y is a "phosphor layer portion." Hereinafter, the sectoral region 2Y will also be referred to as the "fluorescent region 2Y." When irradiated with excitation light beam LE, the fluorescent layer of fluorescent region 2Y emits fluorescent light of a color lower in frequency than the excitation light. In the example being described, the excitation light is blue light, and the fluorescent layer emits yellow light, which has a lower frequency than the blue light. This yellow light contains a red component and a green component. Hereinafter, the red component will also be referred to as "red fluorescence" and the green component will also be referred to as "green fluorescence."

[0020] As shown in FIG. 1(a), the surface of the phosphor wheel 2 is perpendicular to the optical axis AX of the first light-collecting optical system. When the excitation light beam LE is incident on the reflective area 2A of the phosphor wheel 2, it is reflected symmetrically with the incident excitation light beam about the optical axis AX, passes through the first focusing optical system via lenses L4 and L3 in that order, and becomes reflected excitation light LER. The reflected excitation light LER passes through the lens L5 constituting the second light collecting optical system, passes through the blue light transmitting region of the color wheel 3, and is collected at the light collecting position Q on the incident surface of the light uniformizing element 4. On the other hand, when the excitation light beam LE is focused on the fluorescent region 2Y of the phosphor wheel 2, it emits yellow fluorescence LF. The fluorescence LF originates from the focusing position P of the excitation light beam LE, and spreads out in a cone shape with the focusing position P as its apex and the optical axis AX as its cone axis, passing through the first focusing optical system, entering lens L5, which is the second focusing optical system, and then focusing at focusing position Q on the entrance surface of the light uniformizing element 4 via the color wheel 3. At this time, part of the fluorescence LF passes through the dichroic mirror DM.

[0021] Lenses L3 and L4 that constitute the first focusing optical system and lens L5 that constitutes the second focusing optical system share the optical axis AX, and the optical system composed of these lenses L3, L4, and L5 forms an "imaging optical system." The above-mentioned focusing position P and focusing position Q are in a conjugate relationship with each other in this imaging optical system, with focusing position P corresponding to the object point and focusing position Q corresponding to the image point. Here, the color wheel 3, which is the "color separating means", will be described with reference to FIG. 1(c).

[0022] The color wheel 3 has three sectorial regions 3B, 3R, and 3G, each with an opening angle of 120 degrees. Sectoral region 3B is a region that selectively transmits blue light, which is excitation light, and is hereinafter also referred to as the "blue light transmitting region 3B." Sectoral region 3R is a region that selectively transmits red fluorescence from the yellow fluorescence LF and is hereinafter also referred to as the "red light transmitting region 3R." Sectoral region 3G is a region that selectively transmits green fluorescence from the fluorescence LF and is hereinafter also referred to as the "green light transmitting region 3G."

[0023] When viewed from the direction of the optical axis AX, the color wheel 3 overlaps with the phosphor wheel 2, with the blue light transmitting region 3B of the color wheel 3 overlapping with the reflective region 2B of the phosphor wheel 2, and the fluorescent region 2Y overlapping with the combined region of the red light transmitting region 3R and the green light transmitting region 3G.

[0024] The phosphor wheel 2 and the color wheel 3 rotate at the same rotational speed while maintaining overlap between their respective regions. When excitation light is emitted, blue reflected excitation light LER reflected by the reflective region 2B of the phosphor wheel 2 and yellow fluorescence LF generated in the fluorescent region 2Y are incident on the color wheel 3 in sequence.

[0025] Since the phosphor wheel 2 and the color wheel 3 rotate at the same rotational speed while maintaining overlap between their respective areas, blue light (excitation light), red fluorescence, and green fluorescence are incident sequentially on the incident surface of the light uniformizing element 4 at the same time intervals.

[0026] The light homogenizing element 4 is an optical element known as an integrator rod or a light tunnel, and a typical example is a hollow light-guiding member having a rectangular parallelepiped light-guiding region with a rectangular cross-section. When converging light is incident on the incident side, the incident light is guided by repeated total reflection on the inner wall of the light-guiding region. However, because the angles of incidence of the individual rays of the converging light are different, the light mixes in the process of being guided by repeated total reflection, and blue, red, and green light beams with uniform intensity distribution are emitted repeatedly in sequence from the exit end.

[0027] By irradiating an image display element, such as a digital mirror device (DMD), with these light beams as illumination light beams, blue, red, and green image light beams of a color image can be obtained, and a color image can be formed. The color image formed is a composite of the three primary color images seen by the viewer in sequence as afterimages.

[0028] FIG. 1( d ) shows a state in which the fluorescence LF and the reflected excitation light LER are converged at a convergence position Q on the incident surface of the light uniformizing element 4 .

[0029] The light source device shown in Figure 1 has an excitation light source unit that emits excitation light from light-emitting elements 1a and 1b and converts the emitted excitation light into an excitation light beam LE, a wavelength conversion member 2 that has a reflection region 2B that is irradiated with the excitation light beam LE and reflects the excitation light beam, and a fluorescent region 2Y that emits fluorescence LF having a wavelength different from that of the excitation light beam.

[0030] It also has a dichroic mirror DM that transmits the fluorescence LF and reflects the excitation light beam LE, a first focusing optical system (lenses L3, L4) that focuses the excitation light beam LF that has passed through the dichroic mirror DM onto the wavelength conversion member 2, a second focusing optical system (lens L5) that focuses the reflected excitation light LER and fluorescence LF from the wavelength conversion member 2 via the first focusing optical system, and a light homogenizing element 4 that homogenizes the reflected excitation light LER and fluorescence LF focused by the second focusing optical system.

[0031] Furthermore, as shown in Figure 1(a), the excitation light beam LE incident on the wavelength conversion member 2 passes through one half of the optically effective surface of the first focusing optical system (the lens part on the right side of the optical axis AX in Figure 1(a)), and the reflected excitation light LER passes through the opposite half of the optically effective surface of the first focusing optical system (lenses L3, L4) via the optical axis AX (the lens part on the left side of the optical axis AX in Figure 1(a)), and the second focusing optical system shares the optical axis AX with the first focusing optical system.

[0032] 1(a), the excitation light beam LE incident on the first focusing optical system is a narrow beam with a small cross section, and its chief ray is parallel to the optical axis AX. The reflected excitation light LER is also a narrow beam parallel to the optical axis AX. Between lenses L3 and L5, the fluorescence light LF is a beam with a small cross section that includes the optical axis AX.

[0033] 1 includes color wheel 3, but a color wheel is not necessarily required. For example, if fluorescent region 2Y, which is the phosphor layer portion of the phosphor wheel, is divided into two equal sector-shaped regions, one of which emits "red fluorescence" and the other emits "green fluorescence," it is possible to obtain light of the three primary colors of blue, red, and green without using a color wheel, and these can be directly focused on the incident surface of light uniformizing element 4.

[0034] An example of the basic configuration of the light source device has been described above. The "change in color" that is to be corrected by the present invention will be explained below.

[0035] The light source device described above is constructed by combining various optical components, and therefore manufacturing errors are unavoidable during the assembly process. In other words, the relative positions of the optical components cannot be perfectly aligned as designed. Furthermore, the light source device described with reference to FIG. 1 includes the phosphor wheel 2 and color wheel 3 as movable components, and therefore the relative positions of the optical components will become misaligned over time.

[0036] As an example, a case where a slight tilt angle Δθ occurs in the rotation axis 2AX of the phosphor wheel 2 will be described with reference to FIG. As shown in Figure 2(a), the excitation light beam LE is focused at a focusing position P on the incident surface of the phosphor wheel 2, and generates fluorescence LF when it enters the fluorescent region 2Y, and is reflected as reflected excitation light LER when it enters the reflective region 2B. Note that the slight tilt of the phosphor wheel is exaggerated in Figure 2(a). At this time, the fluorescent light LF spreads in a cone shape as divergent light, and the incident position on the incident surface of the light uniformizing element 4 is "almost the same" as the light condensing position Q in the state shown in FIG. On the other hand, the angle of incidence of the reflected excitation light LER changes (it changes by twice the tilt angle Δθ of the phosphor wheel 2), so the optical path passing through the lenses L3, L4, and L5 that make up the imaging optical system is different from when Δθ = 0. The optical path of the reflected excitation light LER that has changed in this way deviates from the so-called "paraxial region" of the imaging optical system, and is therefore affected by the aberrations of the imaging optical system, so that the position of incidence on the incident surface of the light uniformizing element 4 becomes position R, which is different from the focusing position Q of the fluorescence LF, as shown in Figure 2(b), for example.

[0037] That is, since the incident position Q of the fluorescence LF and the incident position R of the reflected excitation light LER on the incident side of the light uniformizing element 4 are separated, the light uniformizing effect of the light uniformizing element 4 differs between the fluorescence LF and the reflected excitation light LER.

[0038] For example, if the light uniformizing effect of the light uniformizing element 4 on the reflected excitation light LER is weaker than the light uniformizing effect on the fluorescent light LF, the light intensity of the blue component will be weaker relative to the fluorescent light (red and green components) emitted from the light uniformizing element 4, and the displayed color image will have a weaker blue component and appear reddish. This is the "change in color tone."

[0039] If the tilt angle Δθ is small, the separation distance between the focusing positions Q and R is also small, and the resulting change in color is also small. However, if the tilt angle Δθ becomes large to a certain extent, the change in color exceeds the allowable range and correction becomes necessary.

[0040] An embodiment for correcting such a "change in color tone" will be described below. In this invention, by adjusting at least one of the position and attitude of the optical elements "on the optical path of the excitation light LE" in the excitation light light source unit, the dichroic mirror DM, and the wavelength conversion member 2, it is possible to adjust the focusing position of the reflected excitation light LER and the focusing position of the fluorescence LF on the incident surface of the light homogenizing element 4, and by matching these focusing positions, changes in color can be corrected.

[0041] In the embodiment shown in FIG. 3, the attitude of the dichroic mirror DM is changed by rotation. As shown in FIG. 3, the dichroic mirror DM is rotated clockwise by a small angle from the state shown in FIG. At this time, the focusing position of the excitation light beam LE on the phosphor wheel 2 shifts to the left from the designed position P to a position P1. Accordingly, the fluorescence LF with respect to the imaging optical system is focused at a position P1 as an object point, and the image point is focused at a position T on the incident surface of the light uniformizing element 4. By adjusting the small rotation angle of the dichroic mirror DM so that the focal point of the reflected excitation light LER is at position T, the focal points of the fluorescence LF and the reflected excitation light LER will coincide at position T, and the change in color will be corrected. 3(b) is an explanatory diagram showing the state of the light-collecting positions R and Q on the incident surface of the light homogenizing element 4 before correction. As shown in FIG. 3(c), when the rotation angle of the dichroic mirror DM increases in the clockwise direction, the light-collecting positions R and Q move to the right as shown in FIG. 3(c). At this time, the movement amount of the light-collecting positions R and Q relative to the rotation angle of the dichroic mirror DM is such that the movement amount W1 of the light-collecting position R is greater than the movement amount W0 of the light-collecting position Q.

[0042] Therefore, by adjusting the rotation angle of the dichroic mirror DM, the focusing positions of the reflected excitation light LER and the fluorescence LF can be made to coincide at position T, as shown in FIG. 3(d). In this way, the change in color due to the inclination of the phosphor wheel 2 can be corrected.

[0043] In the above explanation, the displacement W1 of the focusing position of the reflected excitation light LER is larger than the displacement W0 of the focusing position of the fluorescence IF because the optical path of the reflected excitation light LER is farther from the paraxial region than the optical path of the fluorescence LF and is more strongly affected by the aberration of the imaging optical system formed by lenses L3, L4, and L5.

[0044] As is clear from the above explanation, in this invention, the optical paths of the reflected excitation light LER and the fluorescence LF in the imaging optical system are separated, the "influence of aberration in the imaging optical system" acting on both the reflected excitation light LER and the fluorescence LF is made greater or less, and the focusing positions of the reflected excitation light LER and the fluorescence LF are made closer to or coincident with each other, thereby performing "color correction."

[0045] In the embodiment described above, color correction is performed by matching the focusing positions Q and R of the reflected excitation light LER and the fluorescence LF. However, color correction does not necessarily require "matching the focusing positions Q and R of the reflected excitation light LER and the fluorescence LF." Even if the focusing positions Q and R of the reflected excitation light LER and the fluorescence LF do not necessarily match, color can be adjusted by adjusting the distance between the focusing positions Q and R.

[0046] Above, the "focusing positions R, Q of the reflected excitation light LER and the fluorescence LF" on the incident surface of the light homogenizing element 4 have been described as "points." However, in reality, the focusing areas of the reflected excitation light LER and the fluorescence LF are, of course, minute areas, and the focusing positions R, Q shown above correspond to the centers of gravity of the minute areas of the respective focusing areas.

[0047] As long as "the majority of the minute surface areas of the focusing positions Q and R" are both "positionally related to be captured by the incident surface of the light uniformizing element 4," in other words, the center of gravity of the focusing areas of the reflected excitation light LRR and the fluorescence LF should be within the opening captured by the light uniformizing element 4.

[0048] That is, "the focusing position R of the reflected excitation light LER and the focusing position Q of the fluorescence LF are adjustable" means that at least the center of gravity Q of the fluorescence LF and the center of gravity R of the light flux of the reflected excitation light LER are adjustable to be located within the opening of the light uniformizing element 4. If the center of gravity positions Q and R deviate from the opening of the light uniformizing element, both the reflected excitation light LER and the fluorescence LF will become "light that does not effectively contribute to illumination," and the ratio of the fluorescent component to the blue component may significantly deviate from the specified ratio, resulting in the color being outside the allowable range.

[0049] To separate the optical paths of the reflected excitation light LER and the fluorescence light LF in the imaging optical system, the incident position of the excitation light beam LE onto the phosphor wheel 2 can be shifted relative to the designed focusing position P. This can be achieved by changing the direction or "distance from the optical axis AX" of the excitation light beam LE, or by changing the distance between the phosphor wheel 2 and the lens L4.

[0050] That is, it is sufficient to adjust "at least one of the position and attitude" of any of the optical elements on the optical path of the excitation light in the excitation light source unit (for example, in the example of Figure 1(a), lenses L1, L2, beam profiler PR, etc.), dichroic mirror DM, and phosphor wheel 2.

[0051] The embodiment described above and shown in Figure 3 relies on a method of changing the direction of the excitation light beam LE by rotating the dichroic mirror DM in a direction perpendicular to the mirror normal (i.e., by changing the attitude of the dichroic mirror DM).

[0052] The dichroic mirror DM can also change the position of the excitation light beam LE relative to the optical axis AX by, for example, changing its position in the left-right or up-down direction from the position shown in FIG.

[0053] When the dichroic mirror DM is rotated as in the embodiment shown in FIG. 3, it is preferable to align the position of the rotation axis (which is perpendicular to the plane of the drawing) of the dichroic mirror DM with the incident position X of the excitation light beam LE from the excitation light source unit, as shown in FIG. This reduces the change in the optical path length and suppresses the effect on the optical characteristics, making it possible to adjust the color temperature while maintaining high image quality.

[0054] In the embodiment shown in FIG. 5, among the optical elements on the optical path of the excitation light in the excitation light light source unit (light-emitting elements 1a, 1b, microlenses 2a, 2b, lenses L1, L2, beam profiler PR), the position of lens L1 can be adjusted in a direction perpendicular to the optical axis.

[0055] In this way, the position and direction of the excitation light beam LE incident on the dichroic mirror DM can be changed, and therefore the "direction and position" of the excitation light beam LE incident on the lens L3 can be changed, and the incident position of the excitation light beam on the incident surface of the phosphor wheel 2 can be displaced relative to point P.

[0056] Of the optical elements on the optical path of the excitation light in the excitation light light source unit, instead of lens L1, lens L2 or beam profiler PR may be displaced in a direction perpendicular to the optical axis, or the lens position may be changed by tilting the optical axis of lens L1 or lens L2.

[0057] 6 is an embodiment in which the incident position of the excitation light beam LE is displaced relative to point P by slightly displacing the phosphor wheel 2 in the direction of the rotation axis 2AX. In this way, the focusing position of the excitation light beam LE can also be displaced left and right in the figure relative to point P.

[0058] Instead of displacing the phosphor wheel 2 in the direction of the rotation axis 2AX, or in addition to displacing the phosphor wheel 2, the rotation axis 2AX may be tilted by a small angle to change the attitude of the phosphor wheel 2.

[0059] In the embodiment described above, "at least one of the position and attitude" of the optical element L1, dichroic mirror DM, and phosphor wheel 2 on the optical path of the excitation light in the excitation light source unit is adjusted. Such an adjustment mechanism can be implemented using a known appropriate rotation adjustment mechanism or displacement adjustment mechanism. The adjustment operation may be performed manually or automatically using a stepping motor or the like.

[0060] 4 to 6, the parts not shown are of course the same as those in FIG.

[0061] The light source device described above is a single light source device, but two of these units, excluding the light uniforming element 4 and the color wheel 3, can be used as one unit, and the light uniforming element 4 and the color wheel 3 can be made into a common unit to create a high-output light source device.

[0062] FIG. 7 is a diagram illustrating such an example.

[0063] Reference numerals 10A and 10B denote the above-described light source device excluding the light uniformizing element 4 and the color wheel 3 (referred to as a unit light source device), and reference numeral 10C denotes a "light combining element."

[0064] The emitted light LA ​​and LB from the unit light source devices 10A and 10B are reflected excitation light and fluorescent light, respectively. These emitted light LA ​​and LB are combined by the light combining element 10C and enter the incident surface of the common light uniformizing element 4 via the common color wheel 3. The light combining element 10°C totally reflects the emitted light LA ​​and transmits the emitted light LB.

[0065] The unit light source devices 10A and 10B are arranged so that the emitted light beams LA and LB are orthogonal to each other in a plane parallel to the paper.

[0066] By using two unit light source devices 10A and 10B, it becomes possible to display a color image with higher brightness, but if the color temperatures of the two unit light source devices are not the same, the quality of the displayed color image will be reduced.

[0067] By adjusting the incident positions of the reflected excitation light and the fluorescent light on the incident surface of the light uniformizing element 4 using the unit light source devices 10A and 10B, it becomes possible to display a high-brightness, high-quality color image.

[0068] An embodiment of an image display device using the light source device described above will be described below.

[0069] FIG. 8 is a diagram illustrating a projector, which is an image display device that projects and displays a color image.

[0070] The projector 50 includes a light source unit 100 which is an example of a light source device, an illumination optical system 510, and a projection section 520.

[0071] The light source unit 100 is any of the light source devices described in the embodiments above, and causes light L to enter the illumination optical system 510. The light L is an illumination luminous flux homogenized by the light homogenizing element 4 described in the embodiment of the light source device, and is time-divided into blue light (excitation light), red light (fluorescent component), and green light (fluorescent component). The light modulator 540 is, for example, a DMD, which controls the tilt of two-dimensionally arranged minute mirrors and synchronizes blue, red, and green image components with the component light of the light L to express them.

[0072] The light L is converted by the optical modulator 540 into a blue light component image beam, a red light component image beam, and a green light component image beam, and the projection unit 520 projects each color light component image onto a screen in turn. The optical modulator 540 can also use a "liquid crystal panel" instead of a DMD.

[0073] 8, the direction in which the projection image is output from the projection unit 520 is perpendicular to the optical axis direction of the light L output from the light source unit 100. That is, the light source unit 100 is arranged so that the optical axis direction of the light L output from the light source unit 100 is perpendicular to the arrangement direction of the illumination optical system 510 and the projection unit 520, and the light L from the light source unit 100 is directly input to the illumination optical system 510.

[0074] Of course, the layout is not limited to this, and the layout of each part can be changed as appropriate depending on the arrangement of the cooling mechanism, control part, power supply part, etc. that make up the projector 50. For example, when a transmissive light modulation element, such as a transmissive liquid crystal panel, is used for the light modulation section 540, the light L from the light source unit 100 may be made to "enter from below in the figure" on the light modulation section 540 in FIG. 8.

[0075] By including the light source unit 100, the projector 50 can suppress deterioration of the light source due to driving the light source when the illuminance of the light L emitted from the light source unit 100 is set lower than a predetermined illuminance. By lowering the illuminance below a predetermined illuminance, the life of the light source unit 100 is extended, so that the frequency of replacing the light source unit 100 is reduced, and the maintenance work for the projector 50 can be reduced.

[0076] 9 is a diagram illustrating a wearable display device as another example of an image display device. A wearable display device 60 has an appearance as shown in FIG. The wearable display device 60, the appearance of which is shown in FIG. 9(a), is a "head-mounted display" that can be worn on a human head, and is, for example, a head-mounted display device shaped similar to glasses or goggles.

[0077] 9(a), a wearable display device 60 is configured with a front 60a and temples 60b, one pair of which is provided substantially symmetrically on the left and one pair on the right. The front 60a can be configured with a light guide plate 61, and the optical system, control device, etc. are built into the temples 60b.

[0078] 9(b) is a schematic diagram showing a part (the part for the left eye shown in FIG. 9(a)) of the wearable display device 60. The part for the right eye is similar to the part for the left eye. The wearable display device 60 includes a control device 11 , a light source unit 100 , a light amount adjusting section 607 , a movable device 13 having a reflecting surface 14 , a light guide plate 61 , and a half mirror 62 .

[0079] The light source unit 100 is any of the light source devices described above as embodiments. The light from the light source unit 100 is incident on the movable device 13 after the light intensity is adjusted by the light intensity adjustment section 607. The movable device 13 moves the reflecting surface 14 in the X and Y directions based on a signal from the control device 11, and performs two-dimensional scanning of the light from the light source unit 100. The drive control of this movable device 13 is performed, for example, in synchronization with the light emission timing (determined by the position above the image to be displayed) of the light source elements provided in the light source unit 100.

[0080] The scanning light from the movable device 13 is incident on the light guide plate 61. The light guide plate 61 reflects the scanning light on its inner wall surface and guides it to the half mirror 62. The light guide plate 61 is made of a material such as a resin that is transparent to the wavelength of the scanning light.

[0081] The half mirror 62 reflects the light from the light guide plate 61 toward the back side of the wearable display device 60 and emits the light toward the eye 63 of the wearer of the wearable display device 60. The half mirror 62 has, for example, a free-form surface shape. An image of the scanning light is formed on the retina of the wearer's eye 63 by reflection from the half mirror 62. That is, an image is formed on the retina of the wearer's eye 63 by reflection from the half mirror 62 and the lens effect of the crystalline lens in the eyeball.

[0082] Furthermore, spatial distortion of the image is corrected by reflection on the half mirror 62. The wearer can observe an image formed by the light scanned in the X and Y directions.

[0083] By using the half mirror 62, the wearer can observe an image formed by light from the outside world and an image formed by the scanning light in a superimposed manner. Note that a mirror may be provided instead of the half mirror 62, thereby eliminating light from the outside world and allowing the wearer to observe only the image formed by the scanning light.

[0084] Figure 10 is a schematic diagram showing another example of the configuration of a wearable display device 60. To avoid any risk of confusion, the same elements are denoted by the same reference numerals as in Figure 9. The same applies to Figures 11 and 12.

[0085] The control device 11 provided in the wearable display device 60 shown in Figure 10 is installed on each of the left and right temples 60b so as to correspond to the light source unit 100 and movable device 13 incorporated in each of the left and right temples 60b, as shown in Figure 10(a). Alternatively, as shown in FIG. 10(b), a single control device 11 may be installed in a central position of the wearable display device 60 (such as the midpoint between the left and right light guide plates 61), and this may be used as a common control device 11 to control the light source units 100 and movable devices 13 incorporated in each of the left and right temples 60b.

[0086] FIG. 11 shows another example of the configuration of a wearable display device 60, which is in the form of a helmet 65 equipped with a visor 64 including a light guide plate 61. In this embodiment, the light source unit 100, the light amount adjusting section 607, the movable device 13, the reflecting surface 14 and the control device 11 may be built into the helmet 65 as shown in the figure.

[0087] FIG. 12 is a schematic diagram showing yet another example of the configuration of a wearable display device 60. In FIG. The wearable display device 60 in FIG. 12 is a "neckband-type display device" that can be worn around the neck or shoulders of a person.

[0088] In FIG. 12, a wearer 66 wearing a wearable display device 60 on his shoulder is sitting in front of a display 67 placed on a desk D. The display 67 communicates with the wearable display device 60 via short-range wireless communication such as Bluetooth, and outputs a display signal. Wearable display device 60 is equipped with projector 68, which projects an image K of an input keyboard as shown in Fig. 12(b) onto the upper surface of desk D. Projector 68 is similar to projector 50 shown in Fig. 9, and includes a light source device whose embodiment has been described above.

[0089] The wearable display device 60 is equipped with a camera (not shown) in addition to the projector 68, and the camera detects the movement of the wearer's 66 fingers on an image K of an input keyboard projected onto the top surface of the desk D. The information on the detection results of the camera is transmitted, for example, to a control device of the wearable display device 60, and the control device determines which key on the input keyboard the wearer 66 pressed based on the information received from the camera, and displays information corresponding to the determination result on the display 67.

[0090] Hereinafter, an embodiment of a head-up display device as an image display device will be described.

[0091] FIG. 13 is a schematic diagram showing an example of an automobile 400 equipped with a head-up display device 70.

[0092] As shown in FIG. 13(a), the head-up display device 70 is installed near the windshield (windshield 401 or the like) of an automobile 400. Projected light PL emitted from the head-up display device 70 is reflected by the windshield 401 and directed toward an observer (driver 402) who is the user. This allows the driver 402 to view an image projected by the head-up display device 70 as a virtual image. Note that a combiner may be installed on the inner wall surface of the windshield, and the user may view a virtual image by the projected light reflected by the combiner.

[0093] 13(b), the head-up display device 70 includes a light source device, that is, a light source unit 100. The light source unit 100 is the light source device described above. Light emitted from light source unit 100 passes through light intensity adjustment section 707 and is then deflected by movable device 13 having reflecting surface 14. The deflected light passes through a projection optical system consisting of free-form surface mirror 709, intermediate screen 710, and projection mirror 711, and is projected onto windshield 401.

[0094] The head-up display device 70 projects an intermediate image displayed on an intermediate screen 710 onto a windshield 401 of an automobile 400, thereby allowing a driver 402 to visually recognize the intermediate image as a virtual image.

[0095] The light emitted from light source unit 100 has its light intensity adjusted by light intensity adjustment section 707, and then is two-dimensionally scanned by movable device 13 having reflecting surface 14. The projection light scanned two-dimensionally by movable device 13 is reflected by free-form surface mirror 709, where distortion is corrected, and then focused on intermediate screen 710 to display an intermediate image. Intermediate screen 710 is made up of a microlens array in which microlenses are arranged two-dimensionally, and the projection light incident on intermediate screen 710 is magnified in microlens units.

[0096] The movable device 13 reciprocates the reflective surface 14 in two axial directions, thereby two-dimensionally scanning the projection light L incident on the reflective surface 14. The drive control of this movable device 13 is performed in synchronization with the light emission timing of a light emitting element (e.g., a semiconductor laser) provided in the light source unit 100.

[0097] FIG. 14 shows another example of the configuration of the head-up display device 70. In FIG. In the configuration example shown in FIG. 14, the head-up display device 70 includes the imager 20 and a concave mirror 709.

[0098] The imager 20 includes a light source unit 100 which is a light source device.

[0099] Light emitted from the light source unit 100 passes through an illumination system 201 and then irradiates an image forming unit 202. The image forming unit 202 includes a light modulation unit such as a DMD or a liquid crystal panel. A control device 203 controls the light emission drive of the light source (light emitting element) included in the light source unit 100 and the drive of the light modulation unit included in the image forming unit 202. An image generated by the image forming unit 202 is formed as an intermediate image on an intermediate screen 205 by a projection lens 204.

[0100] 14 reflects light L of an image formed on intermediate screen 205 onto windshield 401 of the automobile via concave mirror 709, allowing driver 402 to view virtual image I. Note that a folding mirror may be placed between concave mirror 709 and windshield 401 as required for layout purposes.

[0101] The intermediate screen 205 is configured, for example, with a microlens array in which microlenses are arranged two-dimensionally. In this embodiment, the microlens array is used to control the viewing angle characteristics, thereby enhancing the viewing angle characteristics of the image projected onto the intermediate screen 205 and generating a brighter virtual image.

[0102] Although the preferred embodiment of the invention has been described above, the invention is not limited to the specific embodiment described above, and unless otherwise specifically limited in the above description, various modifications and changes are possible within the spirit of the invention as described in the claims. The image display device is not limited to the configuration of the projector, wearable display device, and head-up display device described above. Furthermore, the image display device is not limited to being attached to an automobile or a human body, but may also be mounted on, for example, a railway vehicle, an airplane, or a ship, or may be mounted on a mobile body such as a robot capable of autonomous or remote-controlled movement, a drone, or an unmanned aerial vehicle, or a non-mobile body such as a work robot that operates a drive target such as a manipulator without moving from its location.

[0103] The effects described in the embodiments of the present invention are merely a list of preferred effects resulting from the invention, and the effects of the invention are not limited to "those described in the embodiments." For example, by utilizing the "color correction function" of the light source device, it is possible to change the color of the displayed color image to one with the normal color temperature and adjust it to a color image with the color of your choice. [Explanation of symbols]

[0104] 1a, 1b Light-emitting element 2a, 2b Condenser lenses L1 and L2 lenses PR Beam Profiler DM Dichroic Mirror L3 and L4 lenses (first focusing optical system) L5 lens (second focusing optical system) 2. Wavelength conversion material (fluorescent plate) 3 Color Plates 4. Light uniformizing element [Prior art documents] [Patent documents]

[0105] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-75221

Claims

1. an excitation light source unit that emits excitation light from one or more light-emitting elements and converts the emitted excitation light into an excitation light beam; a wavelength conversion member having a reflecting portion that is irradiated with the excitation light beam and reflects the excitation light beam, and a phosphor layer portion that emits fluorescence having a wavelength different from that of the excitation light beam; a dichroic mirror that transmits either the excitation light beam or the fluorescence and reflects the other; a first focusing optical system that focuses the excitation light beam that has passed through the dichroic mirror onto the wavelength conversion member; a second focusing optical system that focuses the reflected excitation light and the fluorescent light from the wavelength conversion member via the first focusing optical system; a light homogenizing element that homogenizes the reflected excitation light and the fluorescent light collected by the second light collecting optical system, the excitation light beam incident on the wavelength conversion member passes through one half of an optically effective surface of the first focusing optical system, the reflected excitation light passes through the opposite half of the optically effective surface of the first focusing optical system via an optical axis of the optically effective surface, and the second focusing optical system shares the optical axis with the first focusing optical system; a dichroic mirror, a wavelength converting member, and / or an optical element on the optical path of the excitation light in the excitation light light source unit; a light source device in which the focusing position of the reflected excitation light and the focusing position of the fluorescence at the incident position of the light homogenizing element can be adjusted by adjusting at least one of the position and the attitude of the dichroic mirror, the wavelength converting member, and / or an optical element on the optical path of the excitation light in the excitation light light source unit;

2. 2. The light source device according to claim 1, a light source device in which at least one of the position and the attitude of the optical element on the optical path of the excitation light in the excitation light source section is adjustable;

3. 2. The light source device according to claim 1, A light source device in which at least one of the position and the attitude of the dichroic mirror is adjustable.

4. 2. The light source device according to claim 1, A light source device in which at least one of the position and the attitude of the wavelength conversion member is adjustable.

5. 4. The light source device according to claim 3, The light source device is such that the attitude of the dichroic mirror can be adjusted by rotation in a direction perpendicular to the normal to the mirror.

6. 6. The light source device according to claim 5, A light source device in which the rotation center of the dichroic mirror coincides with the reflection point of the excitation light beam on the dichroic mirror.

7. 2. The light source device according to claim 1, a light source device in which the excitation light is blue light, the fluorescent light is yellow light containing green and red components, and a color separation means for separating the blue light, the green component, and the red component is disposed adjacent to the light uniformizing element.

8. 10. A light source device comprising two light source devices according to claim 1, each of which shares the light uniformizing element and is arranged so that the reflected excitation light and the fluorescent light directed toward the light uniformizing element are combined by a light combining element.

9. An image display device using the light source device according to any one of claims 1 to 8.

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