A projection display device

Abstract

The present application relates to a scanning light source and a projection display device. In the field of a projection image display device in which laser light is modulated according to an image signal and projected, a device that is small, easy to drive control, and has high light use efficiency is desired. The scanning light source includes a laser light source including a semiconductor laser and a first collimator lens that collimates a laser beam output from the semiconductor laser; a condenser lens that condenses the laser beam output from the first collimator lens onto an optical surface of a deflection device; and a second collimator lens that collimates a laser beam output from the deflection device, the deflection device being disposed along a circumference centered on a rotation axis and including an optical surface that is rotatable about the rotation axis, the optical surface being configured such that an inclination angle with respect to the rotation axis varies along the circumference, the inclination angle being configured such that the laser beam is recursively deflected at a certain deflection speed in a certain direction when the optical surface is continuously rotated at a certain speed.

Description

TECHNICAL FIELD

[0001] The present application relates to a scanning light source and a projection display device provided with the scanning light source. BACKGROUND

[0002] Conventionally, a projection display device using laser light is known.

[0003] Patent Document 1 discloses a projection display device provided with a laser light source, an acousto-optic modulator that optically modulates laser light according to an image signal, a polygon mirror that horizontally scans the modulated laser light, and a galvanometer mirror that performs vertical scanning.

[0004] Patent Document 1: Japanese Patent Publication No. 2000-180759

[0005] In the projection display device described in Patent Document 1, the optical scanning unit that simultaneously uses the polygon mirror that performs horizontal scanning and the galvanometer mirror that performs vertical scanning requires a large optical path space because it optically scans in both the horizontal and vertical directions, and there is a problem of device size increase.

[0006] In addition, the galvanometer mirror used in vertical scanning is a device that mechanically reciprocates a reflecting surface, and there are problems that a large amount of time is required to return the reflecting surface to the scanning start position each time scanning is performed, and position control is complicated.

[0007] Instead of the galvanometer mirror, it is also possible to consider using a resonant mirror scanner that is relatively simple to control in vertical scanning, but because the resonant mirror scanner is driven by a sine wave, scanning becomes non-uniform, and the time required to return the mirror to the scanning start position also increases. Therefore, it is not suitable for use in the vertical scanning of a projection display device.

[0008] Therefore, in the field of projection-type image display devices that modulate and project laser light according to an image signal, it is desirable to achieve a device that is small, easy to drive and control, and has high light utilization efficiency. SUMMARY

[0009] A first aspect of the present application is a scanning light source characterized by comprising: a laser light source provided with a semiconductor laser and a first collimator lens that collimates a laser beam output from the semiconductor laser; a deflection device; a condenser lens that condenses the laser beam output from the first collimator lens onto an optical surface of the deflection device; and a second collimator lens that collimates the laser beam output from the deflection device,

[0010] The deflection device is rotatable around a rotation axis and has an optical surface disposed along a circumference centered on the rotation axis, the optical surface being configured so that an inclination angle with respect to the rotation axis varies along the circumference, the inclination angle being configured so that the laser beam is recursively deflected in a certain direction at a certain deflection speed when the optical surface is continuously rotated at a certain speed.

[0011] According to the present application, in the field of a projection-type image display device in which laser light is modulated and projected in accordance with an image signal, a small, easily drive-controlled, and high light utilization efficiency device can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 Fig. 1 is a diagram showing an outline structure of an optical system of a projection display device 1000 according to Embodiment 1.

[0013] Figure 2 Fig. 2 is a typical diagram for showing a basic structure of a single-LD type light source 100 according to Embodiment 1.

[0014] Figure 3 Fig. 3(a) is a diagram showing a Near-Field Pattern of output light of a semiconductor laser; Figure 3 Fig. 3(b) is a diagram showing a Far-Field Pattern of the output light of the semiconductor laser.

[0015] Figure 4 Fig. 4(a) is a diagram showing a beam expansion after passing through a collimator lens 102 for a parallel direction; Figure 4 Fig. 4(b) is a diagram showing a beam expansion after passing through the collimator lens 102 for an orthogonal direction.

[0016] Figure 5 Fig. 5(a) is a typical diagram showing a basic structure of a multi-LD type light source 100 according to Embodiment 1; Figure 5 Fig. 5(b) is a typical diagram showing a basic structure of the multi-LD type light source 100 provided with a beam splitting unit 108.

[0017] Figure 6 Fig. 6(a) is a diagram showing a detailed structure of the beam splitting unit 108; Figure 6 Fig. 6(b) is a diagram showing an output of the beam splitting unit 108.

[0018] Figure 7 Fig. 7(a) is a diagram showing a light source provided with a plurality of columns of semiconductor lasers; Figure 7 Fig. 7(b) is a diagram showing a light source provided with a plurality of columns of semiconductor lasers and the beam splitting unit 108.

[0019] Figure 8(a) of FIG. 1 is a perspective view showing the appearance of the deflector 1 to which the embodiment is applied; Figure 8 (b) of FIG. 1 is a side view of the deflector 1.

[0020] Figure 9 (a) of FIG. 1 is a view for explaining the directions of an incident light beam and a reflected light beam in the deflector 1; Figure 9 (b) of FIG. 1 is a view for explaining the position and the tilt angle of a reflecting surface in the deflector 1.

[0021] Figure 10 (a) of FIG. 2 is a perspective view showing the appearance of the deflector 2 to which the embodiment is applied; Figure 10 (b) of FIG. 2 is a side view of the deflector 2.

[0022] Figure 11 (a) of FIG. 2 is a view for explaining the directions of an incident light beam and a reflected light beam in the deflector 2; Figure 11 (b) of FIG. 2 is a view for explaining the position and the tilt angle of a reflecting surface in the deflector 2.

[0023] Figure 12 (a) of FIG. 3 is a perspective view showing the appearance of the deflector 3 to which the embodiment is applied; Figure 12 (b) of FIG. 3 is a view for explaining the position and the tilt angle of a reflecting surface in the deflector 3.

[0024] Figure 13 (a) of FIG. 4 is a view of the deflector 210 as viewed from the rear of the light source 100; Figure 13 (b) of FIG. 4 is a side view showing a state in which the deflector 210 reflects a laser beam toward a start position of vertical scanning; Figure 13 (c) of FIG. 4 is a view of the collimator lens 202 side as viewed from the light synthesizing section 220 side; Figure 13 (d) of FIG. 4 is a side view showing a state in which the deflector 210 reflects a laser beam toward an end position of vertical scanning; Figure 13 (e) of FIG. 4 is a view of the collimator lens 202 side as viewed from the light synthesizing section 220 side.

[0025] Figure 14 (a) of FIG. 5 is a view showing the relationship between a picture of the reflective light modulation device 340 and a rectangular laser beam scanning range SA; Figure 14 (b) of FIG. 5 is a timing chart showing the condition in which a rectangular light beam scans a picture of the reflective light modulation device 340.

[0026] Figure 15 is a view showing the lighting (extinguishing) timing of the light source 100.

[0027] Figure 16 is a view showing the outline structure of the optical system of the projection display device 1000 to which the embodiment 2 is applied.

[0028] Figure 17 (a) is a graph showing the light beam intensity distribution within a rectangle according to different types of light sources; Figure 17 (b) is a typical perspective view showing the structure of the optical integrator 230; Figure 17 (c) is a typical view for explaining the optical action of the optical integrator 230.

[0029] Figure 18 is a graph showing the outline structure of the optical system of the projection display apparatus 1000 according to Embodiment 3.

[0030] Figure 19 is a graph showing the outline structure of the optical system of the projection display apparatus 1000 according to Embodiment 4.

[0031] Figure 20 is a graph showing the outline structure of the optical system of the projection display apparatus 1000 according to Embodiment 5.

[0032] Figure 21 (a) is a perspective view showing the appearance of the deflector 4 according to Embodiment; Figure 21 (b) is a side view of the deflector 4.

[0033] Figure 22 (a) is a view for explaining the directions of the incident light beam and the transmitted light beam in the deflector 4; Figure 22 (b) is a table showing the values of β (deflection angle) when the material of the base 211b is glass.

[0034] BRIEF DESCRIPTION OF REFERENCE NUMERALS

[0035] 11... semiconductor laser

[0036] 12... light emitting section

[0037] 13... power supply terminal

[0038] 100... light source

[0039] 100B... B light source

[0040] 100G... G light source

[0041] 100R... R light source

[0042] 101... light emitting device

[0043] 102... collimator lens

[0044] 107... beam combiner

[0045] 108... beam splitting unit

[0046] 190 projection screen

[0047] 201 condenser lens

[0048] 202 collimator lens

[0049] 210 deflector

[0050] 210B deflector for B

[0051] 210G deflector for G

[0052] 210R deflector for R

[0053] 211, 211b base

[0054] 212 motor

[0055] 213 reflecting surface

[0056] 213b incident surface

[0057] 214 light beam irradiation position

[0058] 220 light synthesizing section

[0059] 221, 222 dichroic mirror

[0060] 230 optical integrator

[0061] 231 diffusing means

[0062] 232 cylindrical lens

[0063] 310a diffusing plate

[0064] 310b rotary diffusing plate

[0065] 320 transmissive illumination system

[0066] 321 first illumination lens

[0067] 322 second illumination lens

[0068] 330 light path conversion mirror

[0069] 340 reflective light modulating means

[0070] 350 TIR prism

[0071] 360 projection lens

[0072] 1000 projection display device DETAILED DESCRIPTION

[0073] Embodiments of a projection display device and a light source device according to the present application will be described below with reference to the accompanying drawings. Note that the embodiments described below are given by way of illustration only and, for example, the technical means described in detail can be modified as appropriate by those skilled in the art without departing from the scope of the present application.

[0074] Note that in the drawings referred to in the following description, units denoted by the same reference numerals have the same function unless otherwise specified.

[0075] Further, in the following description, for example, when denoted as a positive X direction, it means the same direction as the direction indicated by the X-axis arrow of the illustrated coordinate system, and when denoted as a negative X direction, it means the opposite direction at 180 degrees to the direction indicated by the X-axis arrow of the illustrated coordinate system. Further, when denoted as merely the X direction, it means a direction parallel to the X-axis, regardless of whether it is the same direction as the direction indicated by the X-axis arrow of the illustrated coordinate system. The same applies to directions other than the X direction.

[0076] Further, in the following description, red is sometimes denoted as "R", green is sometimes denoted as "G", and blue is sometimes denoted as "B". Thus, for example, R light and a red light source, a G light source and a green light source, and a B laser and a blue laser are synonymous, respectively.

[0077] [Embodiment 1]

[0078] Figure 1 is a diagram showing the outline structure of an optical system of a projection display device according to Embodiment 1. In this diagram, mechanical structures for arranging optical components, a main body, electrical wiring, and the like are omitted for ease of explanation.

[0079] [Overall structure]

[0080] The projection display device 1000 includes a B light source 100B, a G light source 100G, an R light source 100R, a B deflector 210B, a G deflector 210G, an R deflector 210R, a light combining section 220, a light path conversion mirror 330, an internal total internal reflection (TIR) prism 350, a reflective light modulation device 340, and a projection lens 360. Further, between the light sources of the respective colors and the deflectors of the respective colors, a condenser lens 201 is arranged, and between the deflectors of the respective colors and the light combining section 220, a collimator lens 202 (second collimator lens) is arranged. Furthermore, optionally, the projection display device 1000 can include a projection screen 190.

[0081] The B light source 100B has a semiconductor laser that emits B light, the G light source 100G has a semiconductor laser that emits G light, and the R light source 100R has a semiconductor laser that emits R light. Details of the light sources will be described later.

[0082] The B deflector 210B is a deflector that deflects the B light emitted by the B light source 100B in the DB direction. Similarly, the G deflector 210G is a deflector that deflects the G light emitted by the G light source 100G in the DG direction, and the R deflector 210R is a deflector that deflects the R light emitted by the R light source 100R in the DR direction. Details of the deflectors will be described later.

[0083] A collimator lens 202 is provided between the B deflector 210B and the light synthesizing section 220. Even if the B light (dotted line) is deflected in the DB direction by the B deflector 210B, the B light will be incident on the light synthesizing section 220 as a light ray parallel to the X direction by the action of the collimator lens 202.

[0084] A collimator lens 202 is provided between the G deflector 210G and the light synthesizing section 220. Even if the G light (solid line) is deflected in the DG direction by the G deflector 210G, the G light will be incident on the light synthesizing section 220 as a light ray parallel to the Z direction by the action of the collimator lens 202.

[0085] A collimator lens 202 is provided between the R deflector 210R and the light synthesizing section 220. Even if the R light (one-dot chain line) is deflected in the DR direction by the R deflector 210R, the R light will be incident on the light synthesizing section 220 as a light ray parallel to the X direction by the action of the collimator lens 202.

[0086] The light synthesizing section 220 has a dichroic mirror 221 and a dichroic mirror 222. The dichroic mirror 221 has an optical characteristic that transmits G light and reflects B light. The dichroic mirror 222 has an optical characteristic that transmits G light and B light and reflects R light. The components are arranged so that the optical axis center of the collimator lens 202 for B light and the optical axis center of the collimator lens 202 for G light overlap on the dichroic mirror 221. In addition, the components are arranged so that the optical axis center of the collimator lens 202 for B light, the optical axis center of the collimator lens 202 for G light, and the optical axis center of the collimator lens 202 for R light overlap on the dichroic mirror 222.

[0087] The traveling directions of the B light (dotted line), G light (solid line), and R light (single-dot chain line) are all unified to the positive Z direction by the light synthesizing section 220, but these lights are synthesized in a manner that they do not overlap each other at any time. This is because the deflection scanning timing (phase of deflection) of the B deflector 210B, G deflector 210G, and R deflector 210R is controlled so that each of the B light, G light, and R light does not overlap each other on the screen of the reflection-type light modulating device 340. The scanning method will be described in detail later.

[0088] The B light, G light, and R light emitted from the light synthesizing section 220 are changed in the advancing route to the positive X direction by the light path conversion mirror 330 and are incident on the TIR prism 350.

[0089] The TIR prism 350 is, for example, an internal total reflection prism configured by combining two prisms, which causes the illumination light (B light, G light, R light) to be totally reflected at the air gap surface and be incident on the reflection-type light modulating device 340 at a predetermined angle. As described above, the B light, G light, and R light illuminate different parts of the screen of the reflection-type light modulating device 340 in a manner that they do not overlap each other.

[0090] The reflection-type light modulating device 340 uses, for example, a digital micromirror device (DMD) in which micromirror devices are arranged in an array. The micromirrors corresponding to each display pixel are driven in accordance with the luminance level of the image signal so that their reflection directions are changed by pulse width modulation. However, other kinds of reflection-type light modulating devices such as a reflection-type liquid crystal device can also be used.

[0091] The pixels of the screen area illuminated by the B light are driven in accordance with the luminance level of the B component of the image signal and reflect the B image light at a predetermined angle toward the TIR prism 350. Similarly, the pixels of the screen area illuminated by the G light are driven in accordance with the luminance level of the G component of the image signal and reflect the G image light at a predetermined angle toward the TIR prism 350. In addition, the pixels of the screen area illuminated by the R light are driven in accordance with the luminance level of the R component of the image signal and reflect the R image light at a predetermined angle toward the TIR prism 350. In this way, the reflection-type light modulating device is driven in synchronization with the deflection scanning timing of the B deflector 210B, G deflector 210G, and R deflector 210R.

[0092] The image light (B image light, G image light, R image light) is transmitted from the TIR prism 350 and guided to the projection lens 360 and is projected as a color image. The projection lens 360 is configured by a single or multiple lenses and can have an auto focus adjustment function and a zoom function.

[0093] The projection screen 190 is used when constructing a rear-projection display device. Furthermore, although it is often installed in front-projection scenarios, it is not necessarily required when the user projects onto any wall or other surface.

[0094] [light source]

[0095] The following describes light source B 100B, light source G 100G, and light source R 100R. Specifically, light source B 100B includes a semiconductor laser emitting B light and a collimating lens; light source G 100G includes a semiconductor laser emitting G light and a collimating lens; and light source R 100R includes a semiconductor laser emitting R light and a collimating lens. Except for the emission wavelength of the semiconductor laser, the basic structure of the light sources of various colors is the same; therefore, in the following description, they will sometimes not be distinguished by each color of light, but will only be described as light source 100.

[0096] In this embodiment, the various colors of light sources that can be used include those with a single semiconductor laser (single LD type) and those with multiple semiconductor lasers (multiple LD type). These will be described in turn below.

[0097] (Single LD type)

[0098] Figure 2 This is a typical diagram illustrating the basic structure of a single LD-type light source 100. 11 is a semiconductor laser, 13 is a power supply terminal, and 12 is a light-emitting portion disposed on the semiconductor laser 11; these are packaged as a light-emitting device 101. Additionally, in Figure 2 In China, according to Figure 1 A 100B B light source is used to display the direction of the XYZ coordinate system. Figure 2 In the figure, the long side direction H of the light-emitting part 12 is parallel to the Y direction, and the direction of light emitted from the light-emitting part 12 is parallel to the Z direction.

[0099] The long side direction H of the light-emitting portion 12 is typically the direction in which the active layer extends between the P-type cladding and the N-type cladding on the side of the semiconductor chip constituting the semiconductor laser 11. For example... Figure 2 As shown, in the following description, the direction parallel to the long side of the light-emitting part 12 of the semiconductor laser 11 is sometimes referred to as the "parallel direction", and the direction orthogonal to the long side of the light-emitting part 12 is referred to as the "orthogonal direction". Linearly polarized light is emitted from the light-emitting device 101, and the vibration direction of its electric field is the parallel direction (Y direction).

[0100] It is known that the angular characteristics of the output light of semiconductor laser 11 vary depending on the emission direction. Figure 3 The near-field pattern of the output light is illustrated in (a). Figure 3 Example (b) shows the far-field pattern of the output light.

[0101] like Figure 3 As shown in (a), in the near-field pattern, this can be seen as a beam profile reflecting the shape (long side, short side) of the emitting part. On the other hand, as the beam travels, as... Figure 3 As illustrated in the far-field pattern of (b), the beam gradually expands. That is, viewed from the parallel direction, the beam emitted from the semiconductor laser 11 shows a smaller expansion, traveling within a narrow angular range in a pattern of uniform intensity distribution. On the other hand, viewed from the orthogonal direction, the beam emitted from the semiconductor laser 11 forms a mountain-shaped (Gaussian) intensity distribution pattern, expanding over a wider angular range than the parallel direction as it travels. This is because the active layer of the semiconductor laser is thinner in the orthogonal direction, thus experiencing a greater influence from diffraction during emission. The parallel direction, where the expansion is small, can also be referred to as the slow axis, and the orthogonal direction, where the expansion is large, as the fast axis.

[0102] In this embodiment, such as Figure 2 As shown, a collimating lens 102 (first collimating lens) is used to shape the laser beam output from the semiconductor laser 11. That is, the light emitted from the light-emitting part 12 with a length of Hy1 in the long side direction is collimated by the collimating lens 102, becoming a beam with an elliptical cross-section that travels in the Z direction. Furthermore, the major axis of the ellipse is parallel to the X direction, and the minor axis is parallel to the Y direction.

[0103] Even when passing through collimating lens 102, the light beam will not be perfectly parallel to the optical axis (Z direction). The beam spreads differently in the parallel direction (long side of the light-emitting part) and the orthogonal direction (short side of the light-emitting part). (Reference) Figure 4 (a) and Figure 4 (b) explains the different ways in which the light beam expands after passing through the collimating lens 102. Figure 4 (a) shows the extension for the parallel direction. Figure 4 (b) shows the extension for the orthogonal direction.

[0104] like Figure 4 As shown in (a), although the top of the beam intensity is flat when viewed from the parallel direction, the beam diameter expands as it moves towards the Z direction, therefore the divergence angle cannot be considered good. In contrast, as... Figure 4 As shown in (b), if viewed from the orthogonal direction, it can be seen that even if the distance from the collimating lens 102 changes, the changes in beam intensity distribution and beam diameter are very small. That is, the laser beam transmitted from the collimating lens 102 has higher parallelism in the orthogonal direction (fast axis of the semiconductor laser) than in the parallel direction (slow axis of the semiconductor laser), and has a good divergence angle.

[0105] Returning to Figure 2 , the single-LD-type light source 100 is provided with a beam combiner 107 composed of a cylindrical lens, for example. The beam combiner 107 enlarges the light beam in the parallel direction (Y direction). The light beam emitted from the light source 100 as output light after passing through the beam combiner 107 becomes a rectangular light beam shaped as a substantially rectangular cross section. The long side direction of the rectangle corresponds to the parallel direction (slow axis direction of the semiconductor laser), and the short side direction of the rectangle corresponds to the orthogonal direction (fast axis direction of the semiconductor laser). The light beam output from the light source 100 has a superior divergence angle in the short side direction of the rectangle than in the long side direction.

[0106] As described later, in the present application, the light beam output from the light source 100 is scanned in the orthogonal direction (short side direction of the rectangle) by taking advantage of the superior divergence angle (high parallelism of the light beam) in the orthogonal direction. This is because scanning the light beam in the direction with a superior divergence angle is advantageous in preventing the overlapping of the illumination areas of the respective colors R, G, and B on the screen of the light modulation device.

[0107] (multiple-LD type)

[0108] Figure 5 (a) of FIG. 10 is a typical view for illustrating the basic structure of the multiple-LD-type light source 100. The light source 100 is provided with a laser module LM1 including a plurality of semiconductor lasers and a collimator lens 102 (first collimator lens). The description of each semiconductor laser is omitted because it is repeated in the single-LD-type content. In addition, in (a) of FIG. 10, the directions of the XYZ coordinate system are shown by a B light source 100B of Figure 5 Figure 1

[0109] In the laser module LM1, the plurality of semiconductor lasers are arranged at equal intervals along the Y direction. In addition, each semiconductor laser is arranged in the direction along the Y direction in the long side direction of the light emitting portion 12. Although an example using four semiconductor lasers is shown, the number of devices is not limited to this example.

[0110] The interval of the semiconductor lasers in the Y direction is appropriately set so that the light beam emitted from the light source 100 becomes a rectangular light beam shaped as a substantially rectangular cross section. The long side direction of the rectangle corresponds to the parallel direction (slow axis direction of the semiconductor laser), and the short side direction of the rectangle corresponds to the orthogonal direction (fast axis direction of the semiconductor laser). The light beam output from the light source 100 has a superior divergence angle in the short side direction of the rectangle than in the long side direction.

[0111] In addition, as described above, the light beam output from the light source 100 is scanned in the orthogonal direction (short side direction of the rectangle) by taking advantage of the superior divergence angle (high parallelism of the light beam) in the orthogonal direction. This is because scanning the light beam in the direction with a superior divergence angle is advantageous in preventing the overlapping of the illumination areas of the respective colors R, G, and B on the screen of the light modulation device. Figure 5 ​​As shown in (b), by providing a beam splitting unit 108 to split the parallel beam, the uniformity of beam intensity in a rectangular ray with a roughly rectangular cross-sectional shape can be improved. Figure 6 Example (a) illustrates the specific structure of the beam splitting unit 108, in which a half-reflecting mirror is arranged on the optical axis of each collimating lens 102. Half of the laser beam is transmitted directly through the half-reflecting mirrors and propagates in the Z direction, while the other half is reflected in the Y direction by the half-reflecting mirrors. A total reflection mirror is arranged in the optical path of the reflected light; the light reflected in the Y direction by the half-reflecting mirrors is reflected by the total reflection mirror and propagates in the Z direction. As a result, the four output beams from the four semiconductor lasers are split by the beam splitting unit 108 into eight parallel beams propagating in the Z direction, as shown below. Figure 6 As shown in (b), the uniformity of beam intensity in a rectangular ray with a roughly rectangular cross-sectional shape is improved. Here, the long side of the rectangle corresponds to the parallel direction (the slow axis of the semiconductor laser), and the short side of the rectangle corresponds to the orthogonal direction (the fast axis of the semiconductor laser). Even with the light source 100 equipped with the beam splitting unit 108, the output beam has a better divergence angle in the short side direction of the rectangle than in the long side direction.

[0112] In the example above, multiple semiconductor lasers are arranged in a single column along the Y direction, but it is also possible to configure multiple columns along the Y direction to output rectangular beams. Figure 7 (a) shows that Figure 5 In (a), the device column that was originally a single column is now configured as a laser module LM2 with two columns. Additionally, Figure 7 (b) shows that Figure 5 In (b), the device column that is one column is set to two columns in the laser module LM2. In this way, even if the light source 100 has multiple columns of semiconductor lasers along the Y direction, the output beam has a better divergence angle in the short side direction of the rectangle than in the long side direction.

[0113] [Deflector]

[0114] The following describes deflectors 210B (B), 210G (G), and 210R (R). Although they are deflection devices used to deflect and scan laser beams of different colors, they have the same basic structure, so in the following description, they are sometimes referred to as deflectors 210 without specifying the color. Various variations of deflector 210 are described below.

[0115] (Deflector 1)

[0116] The deflector 1, which is one type of deflector 210, will be described. Figure 8 (a) is a perspective view showing the appearance of deflector 1. Figure 8(b) is a side view of the deflector 1.

[0117] The deflector 1 is provided with a circular plate-shaped base 211 that can rotate, and a motor 212 that rotates the base 211 about the rotation axis AX. On the main surface of the circular plate-shaped base 211, a reflection surface 213 that is a band-shaped optical surface is provided along the circumference. Here, in order to specify the position of the reflection surface, as shown in Figure 8 (a) of the accompanying drawings, the angle coordinate is set in a counterclockwise rotation about the rotation axis AX (0°, 90°, 180°, 270° are shown in the drawing). In addition, the axis BX shown in the drawing is an axis that is parallel to the rotation axis AX and passes through the reflection surface 213. The beam spot position shown as the light beam irradiation position 214 is the position of the beam spot at which the rectangular light beam output from the light source 100 is condensed by the condenser lens 201 Figure 1 ).

[0118] The band-shaped reflection surface 213 is twisted so that the angle with respect to the axis BX (i.e., the rotation axis AX) changes with the position. Referring to Figure 9 (a) and Figure 9 (b), the angle of the reflection surface is described. In Figure 9 (a) and Figure 9 (b), the position of the reflection surface is shown as the position specified by the angle coordinate described in Figure 8 (a). In addition, the inclination angle of the reflection surface is shown as the inclination angle of the reflection surface when the main surface of the circular plate-shaped base 211 (i.e., the surface orthogonal to the axis BX) is taken as a reference.

[0119] As shown in Figure 9 (b), the reflection surface 213 is configured so that the inclination angle of the reflection surface changes linearly with respect to the position of the reflection surface. As shown in Figure 8 (a) and Figure 9 (b), the inclination angle of the reflection surface is discontinuous at the position of 0° (360°) of the reflection surface, and therefore, for ease of description, the inclination angle at the positions of 1° and 359° of the reflection surface is shown in Figure 9 (a).

[0120] When the motor rotates the base 211 in the R direction, the reflection surface 213 also rotates about the rotation axis AX, and therefore, as shown in Figure 8 (a), the angle coordinate of the portion irradiated with the laser beam continuously changes in the manner of 0° → 90° → 180° → 360° (= 0°) → 90° … at the light beam irradiation position 214 shown in

[0121] Even if the portion of the reflection surface irradiated with the laser beam changes due to the rotation of the reflection surface, as shown in Figure 9As shown in (a) of FIG. 10, the incident light beam is also always incident to the reflecting surface 213 at an angle of a with respect to the axis BX. On the other hand, depending on the position of the reflecting surface, the tilt angle of the reflecting surface varies in the range from - θ to + θ. Therefore, as shown in (b) of FIG. 10, the deflector 210 is capable of deflecting the outgoing light beam in the angular range from RDl (with respect to the axis BX (a - 2 x θ)) to RD2 (with respect to the axis BX (a + 2 x θ)). In other words, the deflector 210 is capable of deflecting the outgoing light beam in the angular range from RDl (with respect to the axis BX (a - 2 x θ)) to RD2 (with respect to the axis BX (a + 2 x θ)). Figure 9 As shown in (a) of FIG. 10, the direction of the laser beam reflected by the reflecting surface 213 varies in the angular range of 4 θ from (a - 2 x θ) to (a + 2 x θ) when based on the axis BX. That is, the tilt angle is configured to recursively deflect the laser beam in a certain direction at a certain deflection speed when the optical surface (reflecting surface) is continuously rotated at a certain speed.

[0122] In other words, as shown in (b) of FIG. 10, the deflector 210 is capable of deflecting the outgoing light beam in the angular range from RDl (with respect to the axis BX (a - 2 x θ)) to RD2 (with respect to the axis BX (a + 2 x θ)). In other words, the deflector 210 is capable of deflecting the outgoing light beam in the angular range from RDl (with respect to the axis BX (a - 2 x θ)) to RD2 (with respect to the axis BX (a + 2 x θ)). Figure 8 As shown in (a) of FIG. 10, the direction of the laser beam reflected by the reflecting surface 213 varies in the angular range of 4 θ from (a - 2 x θ) to (a + 2 x θ) when based on the axis BX. That is, the tilt angle is configured to recursively deflect the laser beam in a certain direction at a certain deflection speed when the optical surface (reflecting surface) is continuously rotated at a certain speed. Figure 8 As shown in (a) of FIG. 10, the direction of the laser beam reflected by the reflecting surface 213 varies in the angular range of 4 θ from (a - 2 x θ) to (a + 2 x θ) when based on the axis BX. That is, the tilt angle is configured to recursively deflect the laser beam in a certain direction at a certain deflection speed when the optical surface (reflecting surface) is continuously rotated at a certain speed. Figure 8 As shown in (a) of FIG. 10, the direction of the laser beam reflected by the reflecting surface 213 varies in the angular range of 4 θ from (a - 2 x θ) to (a + 2 x θ) when based on the axis BX. That is, the tilt angle is configured to recursively deflect the laser beam in a certain direction at a certain deflection speed when the optical surface (reflecting surface) is continuously rotated at a certain speed. Figure 8 As shown in (a) of FIG. 10, the direction of the laser beam reflected by the reflecting surface 213 varies in the angular range of 4 θ from (a - 2 x θ) to (a + 2 x θ) when based on the axis BX. That is, the tilt angle is configured to recursively deflect the laser beam in a certain direction at a certain deflection speed when the optical surface (reflecting surface) is continuously rotated at a certain speed.

[0123] Thus, with the deflector 1, unlike the galvanometer mirror or the like, it is possible to recursively deflect the laser beam in a certain direction at an equal speed with a simple driving method of continuously rotating the rotating body at a certain speed. As will be described later, by rotating in synchronization with the driving timing of the motor 212 and the reflective light modulation device 340 (or the image signal input to the reflective light modulation device 340), it is possible to cause the illumination light to scan in the V direction in the screen of the reflective light modulation device 340.

[0124] Further, the manufacturing method of the deflector 1 will be described, and the circular plate-shaped base 211 provided with the belt-shaped reflecting surface 213 along the circumference can be manufactured at low cost by processing a metal base material using a press process, for example. As shown in (a) of FIG. 11, the base 211 is formed by a circular plate-shaped base material 211a and a belt-shaped reflecting surface 213a. The base material 211a is formed by a circular plate-shaped base material 211a, and the reflecting surface 213a is formed by a belt-shaped reflecting surface 213a. Figure 9As illustrated in (a), there are protruding and recessed portions from the main surface of the substrate 211 near the reflective surface 213. To ensure good rotational balance, it is preferable that the cross-section at any position is of equal cross-sectional area when viewed from the section passing through the rotation axis AX. Furthermore, to reduce wind noise, the maximum height of the protrusion from the main surface of the substrate 211 and the maximum depth of the recess are preferably 3 / 4 or less of the average plate thickness. Specifically, the average plate thickness of the substrate 211 is preferably 0.7 mm or more and 2 mm or less, and θ is preferably 3° or more and 6° or less.

[0125] (Deflector 2)

[0126] The deflector 2, which is one type of deflector 210, will be described. Figure 10 (a) is a perspective view showing the appearance of deflector 2. Figure 10 (b) is a side view of deflector 2.

[0127] The deflector 2 includes a circular plate-shaped base 211 and a motor 212 that rotates the base 211 around a rotation axis AX. A strip-shaped reflective surface 213 is provided along the circumference of the main surface of the circular plate-shaped base 211. Here, to specify the position of the reflective surface, as... Figure 10 As shown in (a), the angular coordinates are set by rotating counterclockwise around the rotation axis AX (0°, 90°, 180°, and 270° are shown in the figure). Additionally, the axis BX shown in the figure is parallel to the rotation axis AX and passes through the reflecting surface 213. The beam illumination position 214 shows a rectangular beam output from the light source 100 being focused by the condenser lens 201 (…). Figure 1 The location of the focused beam.

[0128] The strip-shaped reflective surface 213 is twisted such that the angle relative to axis BX (i.e., rotation axis AX) varies with position. (Reference) Figure 11 (a) and Figure 11 (b) explains the angle of the reflecting surface. Figure 11 (a) and Figure 11 In (b), the position of the reflecting surface is shown as that of the surface formed by... Figure 10 The position is defined by the angular coordinates described in (a). In addition, the tilt angle of the reflecting surface is shown as the tilt angle of the reflecting surface when the main surface of the circular plate-shaped substrate 211 (i.e., the surface orthogonal to axis BX) is used as a reference.

[0129] like Figure 11 As shown in (b), the reflecting surface 213 is configured such that the tilt angle of the reflecting surface varies linearly with respect to the position of the reflecting surface. Figure 10 of (a), Figure 11As shown in (b) of FIG. 10, the tilt angle of the reflecting surface is discontinuous at the position of the reflecting surface of 0° (360°), and therefore, for the sake of explanation, the tilt angle at the positions of the reflecting surface of 1° and 359° is shown in (a) of FIG. 10. Figure 11 As shown in (a) of FIG. 10, the tilt angle of the reflecting surface is discontinuous at the position of the reflecting surface of 0° (360°), and therefore, for the sake of explanation, the tilt angle at the positions of the reflecting surface of 1° and 359° is shown in (a) of FIG. 10.

[0130] When the motor rotates the base 211 in the R direction, the reflecting surface 213 also rotates around the rotation axis AX, and therefore, as shown in (a) of FIG. 10, the angle coordinate of the portion irradiated with the laser beam changes continuously in the order of 0°→ 90°→ 180°→ 360° (= 0°)→ 90°... Figure 10

[0131] Even if the reflecting surface rotates and the portion of the reflecting surface irradiated with the laser beam changes, as shown in (a) of FIG. 10, the incident light beam always enters the reflecting surface 213 at an angle of α with respect to the axis BX. On the other hand, depending on the position of the reflecting surface, the tilt angle of the reflecting surface changes in the range from -θ to 0. Therefore, as shown in (a) of FIG. 10, the direction of the laser beam reflected by the reflecting surface 213 changes in the angle range of 2θ from (α - 2xθ) to α when the axis BX is taken as a reference. Figure 11 Figure 11

[0132] In other words, as shown in (b) of FIG. 10, the deflector 210 can deflect the outgoing light beam to scan in the angle range from RDl (with respect to the axis BX (α - 2xθ)) to RD2 (α with respect to the axis BX). When the reflecting surface 213 is continuously rotated in the R direction of (a) of FIG. 10, the outgoing light beam is continuously deflected (scanned) from RDl of (b) of FIG. 10 toward RD2, returns instantaneously to RDl when RD2 is reached, and is deflected (scanned) again toward RD2. Figure 10 Figure 10 Figure 10 Figure 10

[0133] Thus, with the deflector 2, unlike the galvanometer mirror, the laser beam can be deflected to scan recursively at an equal speed in a predetermined direction with a simple driving method of continuously rotating the rotating body at a certain speed. As described later, by rotating in synchronization with the driving timing of the motor 212 and the reflective light modulation device 340 (or the image signal input to the reflective light modulation device 340), the illumination light can be scanned in the V direction in the screen of the reflective light modulation device 340.

[0134] The manufacturing method and the specific dimensions of the deflector 2 are the same as those of the deflector 1.​​​​​​​

[0135] (deflector 3)

[0136] A deflector 3 as one mode of the deflector 210 will be described. Figure 12 (a) of FIG. 10 is a perspective view showing the appearance of the deflector 3, Figure 12 (b) of FIG. 10 is a graph showing the relationship between the position of the reflecting surface of the deflector 3 and the tilt angle.

[0137] The deflector 3 is provided with a circular plate-shaped base 211 and a motor that rotates the base 211 about the rotation axis AX. On the main surface of the circular plate-shaped base 211, a strip-shaped reflecting surface 213 is provided along the circumference. Here, in order to specify the position of the reflecting surface, as shown in (a) of FIG. 10, the angle coordinate is set in counterclockwise rotation about the rotation axis AX (0°, 90°, 180°, 270° are shown in the figure). In addition, the axis BX shown in the figure is an axis that is parallel to the rotation axis AX and passes through the reflecting surface 213. As the light beam irradiation position 214, the position of the light beam spot where the rectangular light beam output from the light source 100 is condensed by the condenser lens 201 (202) is shown. Figure 12 Figure 1

[0138] The strip-shaped reflecting surface 213 is twisted so that the angle with respect to the axis BX (i.e., the rotation axis AX) changes with the position. The tilt angle of the reflecting surface linearly changes from -θ to +θ, and as the position of the reflecting surface, the position specified by the angle coordinate explained in (a) of FIG. 10 is shown. In addition, as the tilt angle of the reflecting surface, the tilt angle of the reflecting surface when the main surface of the circular plate-shaped base 211 (i.e., the surface orthogonal to the axis BX) is taken as the reference is shown. Figure 12

[0139] As shown in (b) of FIG. 10, the reflecting surface 213 is configured so that the tilt angle of the reflecting surface linearly changes within the interval of 0° to 180° and the interval of 180° to 360° of the position of the reflecting surface. In the aforementioned deflector 1, the tilt angle of the reflecting surface linearly changes from -θ to +θ from 0° to 360°, whereas in the deflector 3, the tilt angle of the reflecting surface linearly changes from -θ to +θ within the respective intervals of 0° to 180° and 180° to 360°. In addition, as shown in (a) of FIG. 10, Figure 12 Figure 12 Figure 12

[0140] When the motor rotates the base 211 in the R direction, the reflecting surface 213 also rotates about the rotation axis AX, and thus in (a) of FIG. 10, Figure 12 ​​​​​​The angular coordinates of the portion irradiated with the laser beam at the light beam irradiation position 214 indicated by (a) of FIG. 21 change continuously in the order of 0°→ 90°→ 180°→ 360° (= 0°)→ 90°...

[0141] The relationship between the tilt angle of the reflecting surface and the direction of the outgoing light beam is the same as that of the deflector 1, but in the case of the deflector 3, as shown in the lower part of (b) of FIG. 21, two deflection scans can be performed by rotating the base 211 by one revolution. Therefore, for one frame of image display, the base 211 is rotated by 1 / 2 revolution, and the rotation speed can be reduced, so that it is advantageous in terms of quietness. Figure 12

[0142] Thus, with the deflector 3, unlike the galvanometer mirror, the laser beam can be deflected and scanned recursively in the predetermined direction at an equal speed by a simple driving method of continuously rotating the rotating body at a certain speed. As will be described later, by rotating in synchronization with the driving timing of the motor 212 and the reflective light modulation device 340 (or the image signal input to the reflective light modulation device 340), the illumination light can be scanned in the V direction in the screen of the reflective light modulation device 340.

[0143] In addition, although an example in which one revolution is divided into two intervals of 0° to 180° and 180° to 360° and the tilt angle of the reflecting surface is changed from -θ to +θ in each interval is shown, the tilt angle can be changed in three or more intervals. In addition, it is not limited to the example in which the tilt angle is changed from -θ to +θ, but can be changed in the range from -θ to 0 as in the deflector 2, or the like.

[0144] The manufacturing method and the specific dimensions of the deflector 3 are the same as those of the deflector 1.

[0145] [Scanning method]

[0146] The projection display device 1000( Figure 1 ) has the light source 100 and the deflector 210 described above for each of B, G, and R colors. The rectangular B light beam, G light beam, and R light beam output from the light source 100B, light source 100G, and light source 100R are scanned along the vertical direction (V direction) while illuminating the screen of the reflective light modulation device 340. The portion constituted by the light source 100, deflector 210, condenser lens 201, and second collimator lens 202 can be referred to as a scanning light source.

[0147] Figure 13 (a) of FIG. 21 is a view of the deflector 210 as viewed from the rear of the light source 100, and shows a state in which the laser beam reflected by the reflecting surface of the deflector is parallelized by the collimator lens 202. ​

[0148] Figure 13 (b) shows the state in which the deflector 210 reflects the laser beam toward the starting position of the vertical scan. Figure 13 (c) is a view of the collimating lens 202 side from the light combining section 220 side at this time, typically showing a rectangular beam with a diagonal line area. Additionally, Figure 13 (d) shows the state in which the deflector 210 reflects the laser beam toward the end position of the vertical scan. Figure 13 (e) is a diagram showing the collimating lens 202 side as viewed from the light combining section 220 side at this time, typically showing a rectangular beam with a diagonal line area. Additionally, Figure 13 (b) Figure 13 The coordinate axes recorded in (e) are... Figure 1 The G-axis is shown in correspondence with the deflector 210G. In the case of the B-axis with deflector 210B and the R-axis with deflector 210R, the coordinate axes will be in different directions.

[0149] As illustrated in these figures, the rectangular beam output from the light source 100 is focused by the condenser lens 201 to the beam point position of the reflecting surface 213 of the deflector 210. The beam reflected at the beam point position has an expansion angle but has been parallelized by the collimating lens 202.

[0150] In this embodiment, by rotating the reflective surface of the deflector, the rectangular laser beam can be deflected and scanned along the scanning direction SD.

[0151] exist Figure 14 (a) shows the relationship between the screen of the reflective light modulator 340 and the rectangular laser beam scanning range SA. If the screen size of the reflective light modulator 340 is set to H (horizontal direction) × V (vertical direction), then the rectangular laser beam scanning range SA covers an area H' × V' larger than the screen size.

[0152] Figure 14 (b) is a diagram showing the illumination of the screen of the reflective light modulator 340 by rectangular B-beams, G-beams, and R-beams, with the horizontal axis as the time axis. The B-beams, G-beams, and R-beams vertically scan the screen of the reflective light modulator 340 along the scanning direction SD, completing one frame scan in one frame time. The B-beams, G-beams, and R-beams are configured to be non-overlapping to avoid color mixing at the boundaries of various color regions, and the vertical width of each beam is necessarily configured to be less than 1 / 3 of V'. The vertical width of each beam can be set to be more than 1 / 4 and less than 1 / 3 of the vertical width of the screen of the reflective light modulator 340.

[0153] However, as exemplified by the deflector 1 to the deflector 3, there is a position where the inclination angle is discontinuous on the reflecting surface of the deflector, and there is a concern that stray light will be reflected in an undesirable direction in this portion, resulting in a decrease in display quality. Therefore, in the present embodiment, for example, at a time point when the light beam irradiation position 214 shown in (a) of FIG. 14, (a) of FIG. 15, and (a) of FIG. 16 is located near the position where the inclination angle is discontinuous, the driving of the light source 100 is controlled so that the light source 100 is turned off or the luminance is greatly reduced. Figure 8 Figure 10 Figure 12

[0154] Figure 15 is a graph showing the lighting (turning off) timing of the light source 100 with the horizontal axis as time, in the case where the deflector 1 is used as the deflector 210. At a time point when the display image frame is switched, since the light beam irradiation position is the position where the inclination angle is discontinuous (0° = 360° in the case of the deflector 1), the driving of the light source 100 is controlled so that the light source 100 is turned off or the luminance is greatly reduced in accordance with this time point, as shown in the graph of the lower stage. Figure 15

[0155] In the present embodiment, as explained with reference to (b) of FIG. 13, (d) of FIG. 14, and (d) of FIG. 15, since the rectangular light beam output from the light source 100 is condensed by the condenser lens 201 to the reflecting surface 213 (light beam irradiation position 214) of the deflector 210, the time during which the light beam spot stays at the position where the inclination angle is discontinuous is short. Therefore, the time when the light source 100 is turned off or the luminance is greatly reduced can be a short time, and the display luminance hardly decreases. For example, if the diameter of the ring of the reflecting surface 213 is set to 30 mm, the circumferential length of the reflecting surface 213 is 94.2 mm. If the diameter of the light beam spot after being condensed by the condenser lens 201 is, for example, 1 mm, the proportion of the turning off time can be 1 / 94.2 = 0.0106, and the display luminance hardly decreases. Figure 13 Figure 13

[0156] ​​​​​​As described above, in the present embodiment, instead of using an optical scanning unit that requires reciprocating operation and takes much time to return to the scanning start position each time scanning is performed, such as a galvanometer mirror or a resonant mirror scanner, a vertical deflector that can perform deflection scanning linearly by constant-speed rotation is used to scan the laser beams of B, G, and R. The laser beams of B, G, and R are configured so that the beam cross section is rectangular, the divergence angle in the short side direction of the rectangle is better than in the long side direction, and the deflector performs vertical deflection scanning in the direction in which the divergence angle is better. The laser beams of B, G, and R are condensed by the condensing lens 201 to the reflecting surface 213 of the deflector 210 and reflected by the reflecting surface 213. The reflected laser beams of B, G, and R are parallelized by the collimating lens 202, synthesized by the light synthesizing section 220, and guided to illuminate the screen of the reflective light modulation device 340. The present embodiment is small in size because optical deflection scanning is not performed in the horizontal direction. In addition, in the vertical scanning, because a deflector that does not require reciprocating operation and does not substantially take time to return to scanning is used, a projection display device that is easy to drive and control, has high light utilization efficiency, and has high image quality can be provided.

[0157] [Embodiment 2]

[0158] Embodiment 2 will be described below, and common matters with Embodiment 1 will be simplified or omitted in the description. Figure 16 is a diagram showing the outline structure of the optical system of the projection display device according to Embodiment 2. In this diagram, mechanical structures for arranging optical components, a machine body, electrical wiring, and the like are omitted for convenience of explanation.

[0159] [Overall Structure]

[0160] As with Embodiment 1, the projection display device 1000 of the present embodiment is provided with a B light source 100B, a G light source 100G, an R light source 100R, a B deflector 210B, a G deflector 210G, an R deflector 210R, a light synthesizing section 220, a light path conversion mirror 330, a TIR prism 350, a reflective light modulation device 340, and a projection lens 360. In addition, a condensing lens 201 is arranged between the light sources of each color and the deflectors of each color, and a collimating lens 202 is arranged between the deflectors of each color and the light synthesizing section 220. Furthermore, the projection display device 1000 can be provided with a projection screen 190, as appropriate.

[0161] Embodiment 2 differs from Embodiment 1 in that an optical integrator 230 is provided. The optical integrator 230 is provided to improve the uniformity of the illumination brightness in the direction orthogonal to the direction of deflection scanning of the laser beams, that is, in the horizontal direction of the screen of the reflective light modulation device 340.

[0162] The modification of the light source 100 in Embodiment 1 is described in Figure 17 The rectangular light rays are exemplified in (a) of FIG. 10. The left side shows the rectangular light rays output from the reference Figure 2 The rectangular light rays output from the single-LD-type light source 100 described in (a) of FIG. 10. As can be seen, by using the beam combiner 107, the uniformity of the light beam intensity within the rectangle is high. Figure 17 The central part of (a) of FIG. 11 shows the rectangular light rays output from the reference Figure 5 (a) of FIG. 10 or Figure 5 The rectangular light rays output from the multi-LD-type light source 100 described in (b) of FIG. 11. Figure 17 The right side of (a) of FIG. 12 shows the rectangular light rays output from the reference Figure 7 (a) of FIG. 10 or Figure 7 (b) of FIG. 11. The long side direction of the rectangle corresponds to the parallel direction (slow axis of the semiconductor laser), and the short side direction of the rectangle corresponds to the orthogonal direction (fast axis of the semiconductor laser). The light beam output from the light source 100 diverges well in the short side direction of the rectangle than in the long side direction, and the scan direction SD of the deflector coincides with the short side direction of the rectangle.

[0163] Observing Figure 17 the examples of the central and right side of (a) of FIG. 11, in the case of the multi-LD-type light source, it is easy to reflect the configuration of the semiconductor lasers in the long side direction of the rectangle and cause a distribution in the light beam intensity.

[0164] Therefore, in the present embodiment, the optical integrator 230 that has no effect on the short side direction of the rectangular light beam (deflection scan direction) but makes the intensity distribution uniform in the long side direction (direction orthogonal to the deflection scan direction) is used. Figure 17 (b) of FIG. 13 is a typical perspective view for exemplifying the structure of the optical integrator 230, Figure 17 (c) of FIG. 13 is a typical view for explaining the optical action of the optical integrator 230. The optical integrator 230 is composed of a stripe-shaped diffusion device 231 that diffuses the light beam in the long side direction of the rectangle (direction orthogonal to the deflection scan direction), and a cylindrical lens 232 that condenses the light beam diffused by the diffusion device 231 to the target surface (picture of the reflection-type light modulation device).

[0165] Due to the provision of the optical integrator 230, even in the case of using the multi-LD-type light source, it is possible to make the light beam intensity in the long side direction of the rectangle uniform as in the case of the single-LD-type light source.

[0166] In addition, in Figure 16In the present embodiment, the optical integrator 230 is disposed between the light synthesizing section 220 and the light path conversion mirror 330, and can be disposed at any position between the collimator lens 202 and the reflective light modulation device 340 as long as it can condense the light beams onto the target surface (the screen of the reflective light modulation device).

[0167] As described above, in the present embodiment, the optical scanning unit that needs reciprocating operation and takes much time to return to the scanning start position each time of scanning, such as a galvanometer mirror or a resonant mirror scanner, is not used, but a vertical deflector that can perform linear deflection scanning by constant speed rotation is used to scan the laser beams of B, G, and R. The laser beams of B, G, and R are configured so that the beam cross section is rectangular, the divergence angle in the short side direction of the rectangle is better than that in the long side direction, and the deflector performs vertical deflection scanning in the direction in which the divergence angle is better. The laser beams of B, G, and R are condensed by the condensing lens 201 to the reflecting surface 213 of the deflector 210 and reflected by the reflecting surface 213. The reflected laser beams of B, G, and R are parallelized by the collimator lens 202, synthesized by the light synthesizing section 220, and guided to illuminate the screen of the reflective light modulation device 340. In the present embodiment, since the optical integrator 230 is provided in the optical path, the uniformity of the irradiation beam intensity in the horizontal direction of the screen can be improved. The present embodiment is small in size since no optical deflection scanning is performed in the horizontal direction. In addition, in the vertical scanning, since the deflector that does not need reciprocating operation and has substantially no time required for return scanning is used, a projection display device that is easy to drive control, has high light utilization efficiency, and has high image quality can be provided.

[0168] [Embodiment 3]

[0169] Embodiment 3 will be described below, and matters common to Embodiment 1 or Embodiment 2 will be simplified or omitted in the description. Figure 18 is a diagram showing the outline structure of the optical system of the projection display device according to Embodiment 3. In this diagram, the mechanical structure for disposing the optical components, the body, the electrical wiring, and the like are omitted for convenience of explanation.

[0170] Embodiment 3 has the optical integrator 230 as in Embodiment 2, and further has the diffusion plate 310a and the catoptric illumination system 320. In the present embodiment, the target surface (the reference surface of the optical integrator 230, which is described in (c) of FIG. 10) is set at the position of the diffusion plate 310a, not the screen of the reflective light modulation device. Further, the catoptric illumination system 320 composed of the first illumination lens 321 and the second illumination lens 322 is used to catoptrically and image the illumination light emitted as diffused light from the diffusion plate 310a onto the screen of the reflective light modulation device 340 to perform illumination. Figure 17

[0171] ​According to the present embodiment, in addition to the same effects as those of Embodiment 2, there is an advantage of controlling the F number of the image light from the reflection-type light modulating device 340 toward the projection lens 360 by the diffusion plate 310a.

[0172] [Embodiment 4]

[0173] Embodiment 4 will be described below, and common matters with Embodiments 1 to 3 will be simplified or omitted in the description. Figure 19 Fig. 14 is a diagram showing an outline structure of an optical system of a projection display apparatus according to Embodiment 4. In this diagram, mechanical structures for disposing optical components, a machine body, electrical wiring, and the like are omitted for convenience of explanation.

[0174] Embodiment 4 has the optical integrator 230, the diffusion unit, and the turning mirror illumination system 320 as in Embodiment 3. In Embodiment 3, the fixed diffusion plate 310a is used as the diffusion unit, whereas in the present embodiment, the rotary diffusion plate 310b is used. The rotary diffusion plate 310b is a circular plate-shaped diffusion plate that is rotated by a motor. In the case of the fixed diffusion plate 310a, the diffusion characteristics are determined at each spatial position, and it is difficult to suppress flicker (flicker of bright spots) caused by laser light. In contrast, in the rotary diffusion plate 310b, the diffusion characteristics at each spatial position are not fixed, and the diffusion characteristics at each spatial position change over time with rotation, and thus an effect of suppressing flicker can be obtained. In addition, since it is only necessary to cause the diffusion characteristics at each spatial position to change over time, the diffusion plate does not necessarily have to be moved by rotation, and for example, it can be a moving diffusion plate that performs linear reciprocating motion or swinging motion.

[0175] In addition, in the example of Figure 19 , one optical integrator 230 is provided for the combined light of B light and G light, one is provided for R, and the target surface of each optical integrator 230 is made to coincide with the diffusion surface of the rotary diffusion plate 310b.

[0176] As described above, according to the present embodiment, in addition to the same effects as those of Embodiment 3, there is an advantage of being able to suppress flicker (flicker of bright spots) caused by laser light.

[0177] [Embodiment 5]

[0178] Embodiment 5 will be described below, and common matters with Embodiments 1 to 4 will be simplified or omitted in the description. Figure 20 Fig. 15 is a diagram showing an outline structure of an optical system of a projection display apparatus according to Embodiment 5. In this diagram, mechanical structures for disposing optical components, a machine body, electrical wiring, and the like are omitted for convenience of explanation.

[0179] [Overall configuration]

[0180] As with Embodiment 1, the projection display device 1000 of the present embodiment is provided with a B light source 100B, a G light source 100G, an R light source 100R, a B deflector 210B, a G deflector 210G, an R deflector 210R, a light combining section 220, a light path conversion mirror 330, a TIR prism 350, a reflective light modulation device 340, and a projection lens 360. In addition, between the light sources of the respective colors and the deflectors of the respective colors, a condensing lens 201 is disposed, and between the deflectors of the respective colors and the light combining section 220, a collimating lens 202 is disposed. Further, optionally, the projection display device 1000 can be provided with a projection screen 190.

[0181] In Embodiments 1 to 4, as the B deflector 210B, the G deflector 210G, and the R deflector 210R, a deflector in which a strip-shaped reflecting surface 213 is provided on a circumferential direction on a main surface of a circular plate-shaped base 211, i.e., a reflective deflector, is used. In contrast to this, Embodiment 5 is provided with a transmissive deflector, not a reflective deflector.

[0182] (Deflector 4)

[0183] Hereinafter, a deflector 4 which is one mode of the transmissive deflector 210 will be described. Figure 21 (a) of FIG. 4 is a perspective view showing an external appearance of the deflector 4, Figure 21 (b) of FIG. 4 is a side view of the deflector 4.

[0184] The deflector 4 is provided with a circular plate-shaped base 211b which is a base portion composed of a light-transmissive material, and a motor 212 which rotates the base 211b around a rotation axis AX. On a main surface of the circular plate-shaped base 211b, a strip-shaped incident surface 213b which is a strip-shaped optical surface is provided in a circumferential direction. Here, in order to specify a position of the incident surface, as shown in (a) of FIG. 4, an angle coordinate is set in a counterclockwise direction around the rotation axis AX (0°, 90°, 180°, 270° are shown in the figure). In addition, an axis BX shown in the figure is an axis which is parallel to the rotation axis AX and passes through the incident surface 213b. As a light beam irradiation position 214, a light beam point position at which a rectangular light beam output from the light source 100 is condensed by the condensing lens 201 (202) is shown. Figure 21 Figure 20 The strip-shaped incident surface 213b is twisted so that an angle with respect to the axis BX (i.e., the rotation axis AX) changes with a position. Referring to (a) of FIG. 4, the angle of the incident surface will be described. In (a) of FIG. 4, as a position of the incident surface, a position at which the rectangular light beam output from the light source 100 is condensed by the condensing lens 201 (202) is shown.

[0185] The strip-shaped incident surface 213b is twisted so that an angle with respect to the axis BX (i.e., the rotation axis AX) changes with a position. Referring to (a) of FIG. 4, the angle of the incident surface will be described. In (a) of FIG. 4, as a position of the incident surface, a position at which the rectangular light beam output from the light source 100 is condensed by the condensing lens 201 (202) is shown. Figure 22 Figure 22 Figure 21 ​​​the position specified by the angle coordinates of (a). In addition, the inclination angle of the incidence plane is shown with respect to the principal surface (i.e., the surface orthogonal to the axis BX) of the circular plate-shaped base 211b.

[0186] As shown in (a) of FIG. 10, the incidence plane 213b is configured so that the inclination angle of the incidence plane linearly changes with respect to the position of the incidence plane. As shown in (a) of FIG. 10, the inclination angle of the incidence plane is discontinuous at the position of 0° (360°) of the incidence plane, and thus the inclination angles at the positions of 1° and 359° of the incidence plane are shown in (a) of FIG. 10 for ease of explanation. Figure 22 Figure 21 Figure 22

[0187] When the motor rotates the base 211b in the R direction, the incidence plane 213b also rotates around the rotation axis AX, and thus the angle coordinates of the portion irradiated with the laser beam continuously change in the manner of 0° → 90° → 180° → 360° (= 0°) → 90° at the light beam irradiation position 214 shown in (a) of FIG. 10. Figure 21

[0188] Even if the portion of the incidence plane irradiated with the laser beam changes due to the rotation of the incidence plane, as shown in (a) of FIG. 10, the incident light beam always enters the incidence plane 213b at an angle of α with respect to the axis BX. On the other hand, the inclination angle of the incidence plane changes in the range from -θ to +θ depending on the position of the incidence plane. Thus, as shown in (a) of FIG. 10, the direction of the outgoing laser beam changes in the angular range of 2 x β from (α + β) to (α - β) with respect to the axis BX by refraction when entering the circular plate-shaped base 211b composed of a light-transmissive material and refraction when exiting the base 211b. Figure 22 Figure 22

[0189] Here, β is determined depending on the inclination angle θ of the incidence plane 213b, the refractive index n of the base 211b composed of a light-transmissive material, and the incident angle α. In (b) of FIG. 10, the values of β when the material of the base 211b is glass are shown in tabular form. Figure 22

[0190] As shown in (b) of FIG. 10, the deflector 210 of the present embodiment can deflect the outgoing light beam to scan in the angular range from DF1 (with respect to the axis BX (α - β)) to DF2 (with respect to the axis BX (α + β)). When the incidence plane 213b is continuously rotated in the R direction of (a) of FIG. 10, the outgoing light beam is deflected from DF1 to DF2. Figure 21 Figure 21 Figure 21 ​​​​​​​​​DF2 of (b) is continuously deflected (scanned) toward DF1, momentarily returns to DF2 at reaching DF1, and is deflected (scanned) again toward DF1. In addition, if the incident surface 213b is rotated in the opposite direction of the R direction, the outgoing light beam will be deflected from Figure 21 DF1 of (b) is continuously deflected (scanned) toward DF2, momentarily returns to DF1 at reaching DF2, and is deflected (scanned) again toward DF2.

[0191] Thus, with the deflector 4, unlike the galvanometer mirror, it is possible to continuously deflect and scan the laser beams in the predetermined direction at an equal speed with a simple driving method of continuously rotating the rotating body at a certain speed. By rotating the motor 212 in synchronization with the driving timing of the reflective light modulation device 340 (or the image signal input to the reflective light modulation device 340), it is possible to scan the illumination light in the V direction in the screen of the reflective light modulation device 340.

[0192] The manufacturing method of the deflector 4 will be described. The circular plate-shaped base body 211b provided with the belt-shaped incident surface 213b along the circumference can be manufactured at low cost by processing a metal base material using a press process, for example. As shown in (a) of FIG. 14, the base body 211b is provided with a portion protruding from the main surface of the base body 211b and a recessed portion in the vicinity of the incident surface 213b. In order to have a good rotation balance, it is preferable that the cross section at any position passing through the rotation axis AX be a shape having an equal cross-sectional area. Figure 22

[0193] As described above, in the present embodiment, instead of using an optical scanning unit that needs to reciprocate and takes much time to return to the scanning start position each time in a galvanometer mirror or a resonant mirror scanner, a vertical deflector that can linearly perform deflection scanning by constant-speed rotation is used to scan the laser beams of B, G, and R. The laser beams of B, G, and R are configured to have a rectangular beam cross section, to have a good divergence angle in the short side direction of the rectangle than in the long side direction, and the deflector performs vertical deflection scanning in the direction of the good divergence angle. The laser beams of B, G, and R are condensed by the condensing lens 201 to the incident surface 213b of the deflector 210 and are incident to the base body 211b, are deflected and transmitted due to refraction. The transmitted laser beams of B, G, and R are parallelized by the collimating lens 202, are synthesized by the light synthesizing section, and are guided to illuminate the screen of the reflective light modulation device 340. The present embodiment is small in size because optical deflection scanning is not performed in the horizontal direction. In addition, in the vertical scanning, because a deflector that does not need to reciprocate and does not substantially take time to return to scanning is used, it is possible to provide a projection display device that is easy to drive control, has a high light utilization rate, and has high image quality.

[0194] [Other Embodiments]​

[0195] The present application is not limited to the above-described embodiments and specific examples, and various modifications and combinations can be made within the technical scope of the present application.

[0196] For example, modifications are exemplified with respect to the light source and the deflector, but further modifications can be made on the basis of these modifications in order to adapt to the specifications of the projection display device. Different types of light source and deflector can also be used in combination in one projection display device.

Claims

1. A projection display device, characterized by comprising: Possessing: a first semiconductor laser that outputs a laser beam of a first wavelength; a second semiconductor laser that outputs a laser beam of a second wavelength; a first deflection device; a second deflection device; a first collimator lens for the first wavelength that collimates the laser beam output from the first semiconductor laser; a first collimator lens for the second wavelength that collimates the laser beam output from the second semiconductor laser; a first condenser lens that condenses the laser beam output from the first collimator lens for the first wavelength onto an optical surface of the first deflection device; a second condenser lens that condenses the laser beam output from the first collimator lens for the second wavelength onto an optical surface of the second deflection device; a second collimator lens for the first wavelength that collimates the laser beam output from the first deflection device; a second collimator lens for the second wavelength that collimates the laser beam output from the second deflection device; a light synthesizing section that synthesizes the laser beam output from the second collimator lens for the first wavelength and the laser beam output from the second collimator lens for the second wavelength in a manner that they do not overlap each other and that the deflection directions are the same; a light path conversion mirror that guides the light output from the light synthesizing section to a reflective light modulation device; and a projection lens that projects the image light output from the reflective light modulation device, each of the first deflection device and the second deflection device is rotatable around a rotation axis and has an optical surface disposed along a circumference centered on the rotation axis, the optical surface is configured so that an inclination angle with respect to the rotation axis varies along the circumference, the inclination angle is configured so that the laser beam is recursively deflected in a certain direction at a certain deflection speed when the optical surface is continuously rotated at a certain speed.

2. The projection display device according to claim 1, wherein the optical surface possessed by the first deflection device or the second deflection device is a reflection surface that reflects the laser beam condensed by the first condenser lens or the second condenser lens.

3. The projection display device according to claim 1, wherein the optical surface possessed by the first deflection device or the second deflection device is an incidence surface that causes the laser beam condensed by the first condenser lens or the second condenser lens to be incident to a base portion that is transparent.

4. The projection display device according to any one of claims 1 to 3, wherein a cross section of the laser beam output from the first collimator lens for the first wavelength is a substantially rectangular shape with a slow axis of the first semiconductor laser as a long side direction and a fast axis as a short side direction, the first deflection device deflects the laser beam in the short side direction, a cross section of the laser beam output from the first collimator lens for the second wavelength is a substantially rectangular shape with a slow axis of the second semiconductor laser as a long side direction and a fast axis as a short side direction, the second deflection device deflects the laser beam in the short side direction. between the first collimator lens for the first wavelength and the first condenser lens:

5. The projection display apparatus according to claim 4, wherein a beam combiner that amplifies the output light of the first collimator lens for the first wavelength in the direction of the slow axis. ​ 6. The projection display apparatus according to claim 4, wherein a plurality of the first semiconductor lasers are provided, and the plurality of the first semiconductor lasers are arranged in a straight line in a fast axis direction.

7. The projection display apparatus according to claim 6, wherein Further comprising: a light beam splitting unit that splits the output light beams of the plurality of the first semiconductor lasers.

8. The projection display apparatus according to claim 7, wherein Further comprising: an optical integrator that has no influence on intensity distribution in a fast axis direction of the light beams output from the first wavelength-use second collimator lens and the second wavelength-use second collimator lens, but homogenizes intensity distribution in a slow axis direction.

9. The projection display apparatus according to claim 8, wherein The optical integrator further comprises: a stripe-shaped diffusion device that diffuses the light beams in the slow axis direction; and a cylindrical lens that condenses the light beams diffused by the diffusion device onto the screen of the reflective light modulation device.

10. The projection display apparatus according to claim 8 or 9, wherein Further comprising: a stationary or mobile diffusion unit that diffuses the output light of the optical integrator; and a catoptric illumination system that catoptrically reflects and images the diffused light output from the diffusion unit onto the screen of the reflective light modulation device.

Images