Light source device and image projection apparatus

Abstract

To monitor light leakage with high accuracy while avoiding efficiency deterioration of practical light.SOLUTION: The light source device includes a first light source 21 that outputs practical light L1 used for image display or illumination, a second light source 22 that outputs detection light L2 used for detection of light leakage, optical fibers 3 that guide the practical light L1 and the detection light L2 incident from an incident surface 31 and emit the practical light L1 and the detection light L2 from an emission surface 33, an emission-side condensing lens 4 that condenses the practical light LA emitted from the emission surface 33, and a detector 6 that detects a light amount of the detection light LA emitted from the emission surface 33. The first light source 21 is disposed at a position offset from the optical axis 32 of the incident surface 31, the second light source 22 is disposed on the optical axis 32 or at a position offset from the optical axis 32 by a smaller amount than the first light source 21, the emission side condensing lens 4 condenses the practical light L1 emitted from the outer peripheral side of the emission surface 3, and the detector 6 detects the light amount of the detection light L2 emitted from the center side of the emission surface 3.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] There is known an image projection device in which a light source unit and a projection unit are separated and light output from the light source unit is transmitted to the projection unit via an optical fiber (see, for example, Patent Documents 1 and 2). In this type of image projection device, one method to prevent light leakage due to a break in the optical fiber is to extract a portion of the practical light used for image display and monitor the amount of that light using a detector such as a photodetector (PD). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-78622 [Patent Document 2] Japanese Patent Application Publication No. 2023-97755 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned method has a problem of reducing the efficiency of practical light, and there is room for improvement.

[0005] Therefore, an object of the present disclosure is to provide a light source device and an image projection device that can monitor light leakage with high accuracy while avoiding a decrease in the efficiency of practical light. [Means for solving the problem]

[0006] In one aspect, the following solution is provided. a first light source that outputs practical light used for image display or illumination; a second light source that outputs detection light used to detect light leakage; an optical fiber that guides the working light and the detection light incident on an incident surface and outputs the light from an exit surface; a lens that condenses the practical light emitted from the light exit surface; a detector that detects the amount of the detection light emitted from the emission surface, the first light source is disposed at a position offset from the optical axis of the incident surface; the second light source is disposed on the optical axis or at a position offset from the optical axis by a smaller amount than the first light source; the lens condenses the practical light emitted from the outer periphery side of the emission surface, The detector detects the amount of the detection light emitted from the center side of the emission surface. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to monitor light leakage with high accuracy while avoiding a decrease in the efficiency of practical light. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the configuration of a light source device according to a first embodiment of the present disclosure and the optical path of practical light. [Figure 2] 1 is a diagram illustrating a configuration of a light source device according to a first embodiment of the present disclosure and an optical path of detection light. [Figure 3] 3 is a diagram showing the detection light of the light source device according to the first embodiment of the present disclosure, divided into incident light (forward path) and reflected light (return path). FIG. [Figure 4] FIG. 10 is a diagram illustrating the configuration of a light source device according to a second embodiment of the present disclosure and the optical path of detection light. [Figure 5] FIG. 10 is a diagram illustrating the configuration of a light source device and the optical path of detection light according to a third embodiment of the present disclosure. [Figure 6] FIG. 10 is a diagram showing the configuration of a light source device and the optical path of detection light according to a fourth embodiment of the present disclosure. [Figure 7] FIG. 10 is a diagram showing the configuration of a light source device and the optical path of detection light according to a fifth embodiment of the present disclosure. [Figure 8]FIG. 13 is a diagram showing the configuration of a light source device and the optical path of detection light according to a sixth embodiment of the present disclosure. [Figure 9] FIG. 13 is a diagram showing the configuration of a light source device and the optical path of detection light according to a seventh embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings.

[0010] [First Example] FIG. 1 is a diagram showing the configuration of a light source device 1A according to a first embodiment of the present disclosure and the optical path of practical light L1. 1 is applied to, for example, a vehicle projection display device (not shown). A vehicle projection device to which light source device 1A is applied has a light source unit 2 and a projection unit (not shown) separated from each other, and light output from light source unit 2 is transmitted via optical fiber 3 to the projection unit, which either emits the light from light source unit 2 as illumination light or generates and emits image light. With such an image projection device, the projection unit can be made smaller, making it possible to mount the projection unit anywhere in the vehicle.

[0011] Figure 2 is a diagram showing the configuration of the light source device 1A according to the first embodiment of the present disclosure and the optical path of the detection light L2, and Figure 3 is a diagram showing the detection light L2 of the light source device 1A according to the first embodiment of the present disclosure, divided into incident light L2a (outward path) and reflected light L2b (return path). As shown in Figures 1 to 3, the light source device 1A of the first embodiment includes a first light source 21, a second light source 22, an incident-side collecting lens 23, an optical fiber 3, an exit-side collecting lens 4, a reflecting unit 5, and a detector 6.

[0012] 1, the first light source 21 outputs practical light L1 used for image display or illumination. The practical light L1 is laser light having a wavelength in the visible light region. The first light source 21 may output laser light of one color, or may output laser light of multiple colors (e.g., red, green, and blue).

[0013] The first light source 21 is disposed at a position offset from the optical axis 32 of the incident surface 31 of the optical fiber 3, and outputs practical light L1 tilted from a direction approximately normal to the incident surface 31 so that it is incident into the optical fiber 3. Note that an optical system such as an incident-side focusing lens 23 is appropriately installed between the first light source 21 and the incident surface 31.

[0014] 2 and 3, the second light source 22 outputs detection light L2 used to detect light leakage. The detection light L2 is preferably laser light having a wavelength outside the visible light region. This limits the external impact of the detection light L2 even if it leaks.

[0015] The second light source 22 is disposed on the optical axis 32 of the incident surface 31 of the optical fiber 3, and outputs detection light L2 that is incident into the optical fiber 3 from a direction approximately normal to the incident surface 31. Note that an optical system such as an incident-side collecting lens 23 is appropriately installed between the second light source 22 and the incident surface 31.

[0016] 1 to 3, the optical fiber 3 guides the practical light L1 and the detection light L2 incident on the incident surface 31 and emits them from the emission surface 33. At this time, the practical light L1 is incident on the incident surface 31 of the optical fiber 3 at an offset angle, thereby generating emitted light whose intensity is biased outward. Meanwhile, the detection light L2 is incident on the incident surface 31 of the optical fiber 3 from the optical axis 32, thereby generating emitted light whose intensity is biased toward the center.

[0017] As shown in Fig. 1, the output-side collecting lens 4 collects practical light L1 emitted from the output surface 33 of the optical fiber 3. The collected practical light L1 is supplied to a projection unit, for example, via an optical system 7. The output-side collecting lens 4 collects practical light L1 that is emitted with its intensity biased outward, so there is no need for the center to have a lens function. In this embodiment, a hole 41 is formed in the center of the output-side collecting lens 4, penetrating in the direction of the optical axis 34 of the output surface 33.

[0018] 2 and 3, the reflector 5 is disposed at a position facing the exit surface 33 of the optical fiber 3, and reflects the detection light L2 emitted from the center side of the exit surface 33. The detection light L2 reflected by the reflector 5 enters the optical fiber 3 again from the exit surface 33 and is emitted from the entrance surface 31.

[0019] The reflecting section 5 is, for example, a concave (or convex) mirror, and is disposed in the hole 41 of the output-side collecting lens 4. As shown in FIG. 3 , this reflecting section 5 reflects the detection light L2 (incident light L2a) that is emitted from the center of the output surface 33 while diverging, so as to be condensed. The detection light L2 (reflected light L2b) reflected by the reflecting section 5 is condensed and passes through the focal point, and then diverges and is incident on the entire output surface 33. The detection light L2 (reflected light L2b) that is incident from the output surface 33 is guided in the opposite direction to the optical fiber 3, and is emitted from the input surface 31 while diverging.

[0020] 2 and 3, the detector 6 is disposed on the light source unit 2 side, and detects the amount of detection light L2 (reflected light L2b) emitted from the incident surface 31 of the optical fiber 3. For example, as shown in FIG. 3, the detector 6 is disposed at a position offset from the optical axis 32, and detects the amount of detection light L2 (reflected light L2b) collected by the incident-side collecting lens 23.

[0021] According to the light source device 1A of the first embodiment, since light leakage is monitored based on the amount of detected light L2 rather than detecting the amount of light by extracting a portion of the practical light L1, it is possible to avoid a decrease in the efficiency of use of the practical light L1.

[0022] In addition, by changing the incident angle, the light guide paths of the practical light L1 and the detection light L2 within the optical fiber 3 are separated, so that the influence on the practical light L1 is minimized while the amount of the detection light L2 is detected with high accuracy, thereby enabling high-accuracy detection of a broken line.

[0023] Furthermore, the detection light L2 emitted from the exit surface 33 of the optical fiber 3 is reflected by the reflecting section 5 and enters the optical fiber 3 from the exit surface 33, and the amount of light of the detection light L2 emitted from the entrance surface 31 is detected, so that the detector 6 can be disposed in the light source section 2, thereby making the projection section smaller.

[0024] Furthermore, since the reflecting section 5 is disposed in the hole 41 of the output-side condensing lens 4, it is possible to avoid the projection section side from becoming large due to the placement of the reflecting section 5.

[0025] [Other Examples] Next, light source devices 1B to 1G of second to seventh embodiments will be described with reference to Figures 4 to 9. However, for configurations common to the above-mentioned embodiments, the same reference numerals as those in the above-mentioned embodiments will be used, and the explanations of the above-mentioned embodiments may be used.

[0026] FIG. 4 is a diagram showing the configuration of a light source device 1B according to a second embodiment of the present disclosure and the optical path of detection light L2. 4, light source device 1B of the second embodiment differs from the previously described embodiments in that a reflector 5 is formed on output-side collecting lens 4. Output-side collecting lens 4 of the second embodiment has a mirror-finished concave (or convex) reflecting surface at the center of the surface facing output surface 33 of optical fiber 3, which is capable of reflecting detection light L2 output from output surface 33 and allowing it to enter from output surface 33 again, and this reflecting surface functions as reflector 5. Light source device 1B of the second embodiment as described above can also achieve the same effects as those of the previously described embodiments.

[0027] FIG. 5 is a diagram showing the configuration of a light source device 1C according to a third embodiment of the present disclosure and the optical path of the detection light L2. As shown in Figure 5, the light source device 1C of the third embodiment differs from the previously described embodiments in that the second light source 22 and the detector 6 are positioned offset with respect to the optical axis 32, and the reflector 5 is a flat mirror that is positioned at an angle (with respect to the optical axis 34) in the hole 41 of the exit-side focusing lens 4.

[0028] The second light source 22 is disposed at a position offset from the optical axis 32 by a smaller amount than the first light source 21, and the detector 6 is disposed at a position offset on the opposite side of the second light source 22 with the optical axis 32 as the axis of symmetry. When the detection light L2 output from the second light source 22 is incident on the incident surface 31 of the optical fiber 3 at a predetermined incident angle, it is emitted from the exit surface 33 with an exit angle (spread) corresponding to the incident angle. The emitted detection light L2 is reflected by the inclined surface of the reflector 5 (mirror) and re-incident from the exit surface 33 with a re-incident angle equal to the exit angle. The re-incident detection light L2 then exits from the incident surface 31 with an exit angle (spread) corresponding to the re-incident angle, so that the light amount can be detected by the detector 6, which is disposed offset on the opposite side of the second light source 22 with the optical axis 32 as the axis of symmetry. Even with the light source device 1C of the third embodiment, the same effects as those of the above-mentioned embodiments can be obtained.

[0029] FIG. 6 is a diagram showing the configuration of a light source device 1D according to a fourth embodiment of the present disclosure and the optical path of detection light L2. As shown in FIG. 6, the light source device 1D of the fourth embodiment differs from the previously described embodiments in that the reflector 5 is a reflective film disposed on the exit-side collecting lens 4. The reflector 5, which is a reflective film, is disposed in the center of the exit-side collecting lens 4, facing the exit surface 33 of the optical fiber 3, and reflects the detection light L2 emitted from the exit surface 33 and makes it re-enter the exit surface 33. The light source device 1D of the fourth embodiment can achieve the same effects as the previously described embodiments. Note that it is desirable for the reflective film functioning as the reflector 5 to transmit the wavelength of the practical light L1 and reflect the wavelength of the detection light L2. This improves the utilization efficiency of the practical light L1.

[0030] Figure 7 shows the configuration of a light source device 1E according to a fifth embodiment of the present disclosure and the optical path of the detection light L2, Figure 8 shows the configuration of a light source device 1F according to a sixth embodiment of the present disclosure and the optical path of the detection light L2, and Figure 9 shows the configuration of a light source device 1G according to a seventh embodiment of the present disclosure and the optical path of the detection light L2. As shown in FIGS. 7 to 9, light source devices 1E to 1G of the fifth to seventh embodiments differ from the above-described embodiments in that the detector 6 is disposed on the exit surface 33 side of the optical fiber 3.

[0031] For example, in a fifth embodiment shown in Fig. 7, the detector 6 is placed between the exit surface 33 and the exit-side collecting lens 4. In a sixth embodiment shown in Fig. 8, the detector 6 is placed on a flat surface formed in the center of the exit-side collecting lens 4. In a seventh embodiment shown in Fig. 9, the detector 6 is placed in a hole 41 formed in the center of the exit-side collecting lens 4.

[0032] In the fifth to seventh embodiments, light leakage is monitored based on the amount of detection light L2, rather than detecting the amount of light by extracting a portion of the practical light L1, so that a decrease in the efficiency of the practical light L1 can be avoided. Furthermore, by changing the angle of incidence, the light guide paths of the practical light L1 and the detection light L2 within the optical fiber 3 are separated, so that the amount of the detection light L2 can be detected with high accuracy while suppressing the effect on the practical light L1.

[0033] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of components of the above-described embodiments.

[0034] For example, the detection light reflected by the reflector may be detected by a detector disposed on the exit surface side of the optical fiber, rather than being re-entered into the optical fiber. The light source device of the present invention can be applied not only to image projection devices, but also to lighting devices and the like.

[0035] The present invention includes the following embodiments (examples).

[0036] [1] A first light source that outputs practical light used for image display or illumination; a second light source that outputs detection light used to detect light leakage; an optical fiber that guides the working light and the detection light incident on an incident surface and outputs the light from an exit surface; a lens that condenses the practical light emitted from the light exit surface; a detector that detects the amount of the detection light emitted from the emission surface, the first light source is disposed at a position offset from the optical axis of the incident surface; the second light source is disposed on the optical axis or at a position offset from the optical axis by a smaller amount than the first light source; the lens condenses the practical light emitted from the outer periphery side of the emission surface, The detector detects the amount of the detection light emitted from the center side of the emission surface.

[0037] [2] The light source device according to [1], wherein the detection light has a wavelength outside the visible light region.

[0038] [3] The detector comprises: Between the light exit surface and the lens, a flat surface formed in the center of the lens; or The light source device according to [1] or [2], wherein the light source device is arranged in either one of the holes formed in the center of the lens.

[0039] [4] A reflector that reflects the detection light emitted from the center side of the emission surface, The light source device according to [1] or [2], wherein the detector detects the amount of the detection light reflected by the reflecting portion.

[0040] [5] The reflecting portion reflects the detection light emitted from the center side of the emission surface so that the detection light is incident from the emission surface, The light source device according to [4], wherein the detector is disposed on the incident surface side and detects the amount of the detection light emitted from the incident surface.

[0041] [6] The reflecting portion is a concave or convex mirror disposed at the center of the lens; a flat mirror disposed at an angle in the center of the lens; a reflective film disposed at the center of the lens; or The light source device according to [4] or [5], wherein the lens has a reflective surface formed in the center thereof, and the reflective surface has either a concave or convex shape.

[0042] [7] The second light source is disposed at a position offset from the optical axis smaller than the first light source; The light source device according to [5] or [6], wherein the detector is disposed at a position offset on the opposite side of the second light source with the optical axis as an axis of symmetry.

[0043] [8] An image projection device comprising the light source device according to any one of [1] to [7]. [Explanation of symbols]

[0044] 1A~1G light source device 2 Light source section 21 1st light source 22 Second light source 23 Incident side condenser lens 3. Optical Fiber 31 Incidence plane 32 Optical axis 33 Exit surface 34 Optical axis 4. Output side condenser lens 41 Hole 5 Reflector 6 Detector 7 Optical system L1 practical light L2 detected light L2a incident light L2b reflected light

Claims

1. a first light source that outputs practical light used for image display or illumination; a second light source that outputs detection light used to detect light leakage; an optical fiber that guides the working light and the detection light incident on an incident surface and outputs the light from an exit surface; a lens that condenses the practical light emitted from the light exit surface; a detector that detects the amount of the detection light emitted from the emission surface, the first light source is disposed at a position offset from the optical axis of the incident surface; the second light source is disposed on the optical axis or at a position offset from the optical axis by a smaller amount than the first light source; the lens condenses the practical light emitted from the outer periphery side of the emission surface, The detector detects the amount of the detection light emitted from the center side of the emission surface.

2. The light source device according to claim 1 , wherein the detection light has a wavelength outside the visible light region.

3. The detector comprises: Between the light exit surface and the lens, a flat surface formed in the center of the lens; or The light source device according to claim 1 , wherein the light source device is disposed in any one of a hole formed in the center of the lens.

4. a reflecting portion that reflects the detection light emitted from a center side of the emission surface, The light source device according to claim 1 , wherein the detector detects the amount of the detection light reflected by the reflecting portion.

5. the reflecting portion reflects the detection light emitted from the center side of the emission surface so that the detection light is incident from the emission surface, The light source device according to claim 4 , wherein the detector is disposed on the incident surface side and detects the amount of the detection light emitted from the incident surface.

6. The reflecting portion is a concave or convex mirror disposed at the center of the lens; a flat mirror disposed at an angle in the center of the lens; a reflective film disposed at the center of the lens; or 5. The light source device according to claim 4, wherein the lens has a reflective surface formed at a center thereof and having either a concave or convex shape.

7. the second light source is disposed at a position offset from the optical axis by a smaller amount than the first light source; The light source device according to claim 5 , wherein the detector is disposed at a position offset on the opposite side of the second light source with respect to the optical axis as an axis of symmetry.

8. An image projection device comprising the light source device according to any one of claims 1 to 7.

Images