Illumination device and endoscope device

Abstract

To provide an illumination device capable of determining presence or absence of an abnormality on a timely basis.SOLUTION: An illumination device 1 includes: an excitation source 6 for emitting excitation light L1; a fluorescent body 4a for receiving the excitation light L1 and emitting fluorescence; an optical sensor 61 for outputting a detection signal s0 based on detection light L3 with at least one of the excitation light L1 and the fluorescence as the detection light L3; a mirror device 62 for outputting a plurality of output signals s1 to s3 on the basis of the detection signal s0; a plurality of amplifiers 63 for amplifying the plurality of output signals s1 to s3 with different gains and outputting a plurality of amplification signals sa to sc; and an abnormality determination unit 56 for determining presence or absence of an abnormality on the basis of an amplification signal whose signal level is the highest out of the amplification signals in which the signal level of the plurality of amplification signals sa to sc for the light volume of the detection light L3 is a threshold Vth1 or lower of the plurality of amplification signals sa to sc.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an illumination device and an endoscope device that use a semiconductor light-emitting element. [Background technology]

[0002] Conventionally, lighting devices using semiconductor light-emitting elements are known (see, for example, Patent Document 1). The lighting device described in Patent Document 1 includes a detection circuit having a photoelectric conversion element that converts light into an electrical signal and an amplifier that amplifies and outputs the electrical signal, an amplification factor switching unit that changes the amplification factor of the amplifier, and an abnormality determination unit that determines whether or not an abnormality exists based on the amplified electrical signal. In this lighting device, when the amplification factor is changed by the amplification factor switching unit, if the amount of change in the magnitude of the amplified electrical signal is smaller than a determination threshold, it is determined that an abnormality has occurred. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-194679 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the lighting device described in Patent Document 1, when the amplification factor of the amplifier is switched, a period occurs during which an abnormality in the lighting device cannot be detected, which causes a problem in that it is not possible to determine whether or not there is an abnormality in the lighting device.

[0005] In view of this, the present disclosure provides a lighting device etc. that can timely determine the presence or absence of an abnormality. [Means for solving the problem]

[0006] In order to solve the above problems, the lighting device disclosed herein includes an excitation source that emits excitation light, a phosphor that receives the excitation light and emits fluorescence, an optical sensor that uses at least one of the excitation light and the fluorescence as detection light and outputs a detection signal based on the detection light, a mirror device that outputs a plurality of output signals based on the detection signal, a plurality of amplifiers that amplify the plurality of output signals with different gains and output a plurality of amplified signals, and an abnormality determination unit that determines the presence or absence of an abnormality based on the amplified signal with the maximum signal level among the plurality of amplified signals, among which the signal level of the plurality of amplified signals with respect to the amount of detection light is equal to or lower than a predetermined threshold.

[0007] In order to solve the above problems, an endoscope apparatus according to the present disclosure includes the above illumination device and an observation device for observing a subject. Effect of the Invention

[0008] According to the lighting device etc. disclosed herein, it is possible to timely determine whether or not there is an abnormality. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a lighting device of a comparative example. [Diagram 2] FIG. 2 is a schematic diagram showing a configuration of a lighting device according to an embodiment. [Diagram 3] FIG. 3 is an external view showing a configuration of a lighting device according to an embodiment. [Figure 4] FIG. 4 is a circuit diagram showing a configuration of an excitation source of the lighting device according to the embodiment. [Diagram 5] FIG. 5 is a block diagram showing the configurations of the optical sensor, the mirror device, and the amplifier of the illumination device according to the embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the amount of light detected by the optical sensor and the signal level of the amplified signal. [Figure 7] FIG. 7 is a schematic diagram showing the configuration of an endoscope apparatus including an illumination device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Summary of the Disclosure) The present disclosure will be outlined with reference to comparative examples.

[0011] FIG. 1 is a schematic diagram showing a lighting device 101 of a comparative example.

[0012] The illumination device 101 of the comparative example is a device that converts the wavelength of excitation light L1 and emits illumination light L2. As shown in the figure, the illumination device 101 includes a light source device 102 that outputs excitation light L1, a light guide member 103, and a phosphor 104a.

[0013] The light guide member 103 guides the excitation light L1 output from the light source device 102 and emits it to the phosphor 104a. The phosphor 104a converts the excitation light L1 into light of a different wavelength and emits it. Specifically, the phosphor 104a fluoresces when the excitation light L1 is input, and diffuses and emits light consisting of a plurality of wavelengths that appears white overall. This emitted light is emitted as illumination light L2.

[0014] The lighting device 101 includes a detection circuit 160 that detects an abnormality in the phosphor 104a, and an abnormality determination unit 156 that determines whether or not there is an abnormality in the phosphor 104a based on the detection result of the detection circuit 160. The detection circuit 160 includes an optical sensor 161 that receives a part of the light emitted from the phosphor 104a as detection light L3 and outputs a detection signal s0, and an amplifier circuit 163 that amplifies the detection signal s0 output from the optical sensor 161 and outputs it.

[0015] Since the light emitted from the phosphor 104a has a wide dynamic range, if the scale of the detection circuit 160 is too small or too large, the amount of the detection light L3 may not be detected accurately. In the comparative example, the gain (amplification rate) of the amplifier circuit 163 is switched when amplifying the detection signal s0 output from the optical sensor 161, thereby making it possible to read the amount of the detection light L3 over a wide range. In the comparative example, the abnormality determination unit 156 reads the signal amplified by switching the gain, and determines whether or not there is an abnormality in the phosphor 104a.

[0016] However, in the illumination device 101 of the comparative example, the level of the amplified signal changes significantly when the gain of the amplifier circuit 163 is switched, and it takes time for the signal level to stabilize after the gain is switched. Therefore, in the comparative example, there is a problem that a period occurs during which an abnormality in the phosphor 104a cannot be detected, making it impossible to determine whether or not there is an abnormality.

[0017] In contrast, the lighting device of this embodiment has a configuration that allows the amount of detection light L3 to be read without switching the gain of the amplifier circuit. For example, in the lighting device of this embodiment, multiple output signals are generated from the detection signal s0 output from the optical sensor, and each of the multiple output signals is amplified with a different gain. Then, from the multiple amplified signals amplified with different gains, an amplified signal suitable for determining the presence or absence of an abnormality is used to determine the presence or absence of an abnormality. This makes it possible to prevent the occurrence of a period in which an abnormality in the lighting device cannot be detected, and makes it possible to timely determine the presence or absence of an abnormality.

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0019] The embodiments described below each show a comprehensive or specific example of the present disclosure. The numerical values, shapes, materials, components, the arrangement and connection of the components, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in the independent claims showing the highest concept are described as optional components.

[0020] (Embodiment) An illumination device according to an embodiment will be described.

[0021] [1. Lighting equipment configuration] The configuration of the lighting device according to the present embodiment will be described with reference to FIGS.

[0022] 2 and 3 are a block diagram and an external view, respectively, showing a configuration of a lighting device 1 according to an embodiment. Fig. 2 also shows an input power source P1 together with the lighting device 1. The input power source P1 is a system power source that supplies AC power to the lighting device 1. The input power source P1 is, for example, a commercial AC power source.

[0023] The lighting device 1 is a device that emits illumination light L2, and includes a light source device 2, a light guide member 3, and a phosphor 4a, as shown in Fig. 2 and Fig. 3. The components of the lighting device 1 may or may not be integrated together. For example, the lighting device 1 may be disposed in a single housing, or may be a combination of multiple devices that are distributed.

[0024] The light source device 2 is a device that emits excitation light L1. As shown in Fig. 2, the light source device 2 has a lighting device 5, an excitation source 6, and an optical member 7. In the present embodiment, the light source device 2 emits excitation light L1. As shown in Fig. 3, the light source device 2 has a housing 2a, and the lighting device 5, the excitation source 6, and the optical member 7 shown in Fig. 2 are accommodated in the housing 2a.

[0025] The lighting device 5 is a device that lights up the excitation source 6 by supplying power to the excitation source 6, and includes a driving device 5a, a light source switching unit 54, a detection circuit 60, and an abnormality determination unit 56. The driving device 5a is a device that controls the power supplied to the excitation source 6, and includes a power supply circuit 51 and an output control circuit 58. The abnormality determination unit 56 and the output control circuit 58 are configured by a controller 5c.

[0026] Each component of the lighting device 1 will now be described.

[0027] [Excitation source] The excitation source 6 includes one or more light emitting elements, and emits excitation light L1. The configuration of the excitation source 6 according to this embodiment will be described below with reference to FIG.

[0028] Fig. 4 is a circuit diagram showing a configuration of the excitation source 6 of the lighting device 1. Note that Fig. 4 also shows a circuit diagram of the light source switching unit 54.

[0029] As shown in FIG. 4, the excitation source 6 includes four light-emitting elements 6a to 6d connected in series. Each of the light-emitting elements 6a to 6d is not particularly limited as long as it is an element that emits light in response to the supplied power. In the present embodiment, each of the light-emitting elements 6a to 6d is a semiconductor laser element that emits blue excitation light. As a result, the excitation source 6 emits excitation light L1, which is a laser light. Note that the electrical connection mode of the multiple light-emitting elements included in the excitation source 6 is not limited to series connection, but may be parallel connection, or a connection mode that combines series connection and parallel connection. In addition, the number of light-emitting elements included in the excitation source 6 is not limited to four, but may be one or more. In addition, each of the light-emitting elements included in the excitation source 6 is not limited to semiconductor laser elements, but may be other solid-state light-emitting elements such as LEDs (Light Emitting Diodes) and organic EL (Electro Luminescence) elements.

[0030] [Light source switching section] The light source switching unit 54 is a circuit that shorts both ends of each light emitting element included in the excitation source 6. The light source switching unit 54 has a plurality of switches 821-824 connected in parallel to the plurality of light emitting elements 6a-6d, respectively. Each of the plurality of switches 821-824 is, for example, a semiconductor relay (in other words, a solid state relay), and has a light emitting diode 82a as a light emitting element and a phototransistor 82b as a light receiving element.

[0031] In each switch, when the phototransistor 82b is in the off state, the driving current I1 flows through the corresponding light-emitting element, whereas when the phototransistor 82b is in the on state, both ends of the corresponding light-emitting element are shorted, so that the driving current I1 does not flow through the corresponding light-emitting element.

[0032] [Power circuit] The power supply circuit 51 is a circuit that supplies power to the excitation source 6. The power supply circuit 51 converts the voltage of the power output by the input power supply P1 and outputs it. In this embodiment, the power supply circuit 51 is a switching power supply circuit that converts the AC power output by the input power supply P1 into DC power. The power supply circuit 51 may be a switching power supply circuit having a power factor correction function.

[0033] [Optical components] 2, the optical member 7 is a member that guides the excitation light L1 output from the excitation source 6 to the optical system. The optical member 7 may be composed of optical components such as a mirror and a lens. In this embodiment, the optical system is the light-guiding member 3, and the optical member 7 reflects the excitation light L1 output from the excitation source 6 toward the first end 3a of the light-guiding member 3. The optical member 7 further collects the excitation light L1 and makes it incident on the first end 3a of the light-guiding member 3.

[0034] [Light guide member] The light-guiding member 3 is an example of an optical system that receives the excitation light L1 and irradiates the phosphor 4a with the excitation light L1. In this embodiment, the light-guiding member 3 is an optical fiber that guides the excitation light L1 and optically connects the light source device 2 and the phosphor 4a. The core diameter of the light-guiding member 3 is, for example, 400 μm. The core diameter of the light-guiding member 3 may be 5 mm or less. The excitation light L1 emitted from the excitation source 6 and collected by the optical member 7 is incident on the first end 3a of the light-guiding member 3. The excitation light L1 is transmitted through the inside of the light-guiding member 3 from the first end 3a of the light-guiding member 3 and is emitted from the second end 3b of the light-guiding member 3.

[0035] [Phosphor] The phosphor 4a is a wavelength conversion member that converts the excitation light L1 into illumination light L2 having a wavelength different from that of the excitation light L1 and emits the illumination light L2. In this embodiment, the phosphor 4a is irradiated with the excitation light L1 emitted from the second end 3b of the light-guiding member 3. In this embodiment, the phosphor 4a is a member in which a fluorescent material is mixed into a light-transmitting material. The phosphor 4a is, for example, a yellow phosphor. The yellow phosphor is, for example, Y3Al5O activated with Ce. 12 , or Ba2SiO4 activated with Eu. The phosphor 4a is excited by a portion of the blue excitation light L1 and emits yellow light as illumination light L2. The phosphor 4a generates white light which is a mixture of the remaining blue excitation light L1 and the yellow light. Most of the white light generated by the phosphor 4a is irradiated into the illumination space as illumination light L2. The remaining portion of the white light excluding most of the white light is incident on a detection circuit 60 which will be described later.

[0036] [Detection circuit] The detection circuit 60 is a circuit that detects an abnormality in the lighting device 1. The detection circuit 60 is disposed to the side of the phosphor 4a. The detection circuit 60 includes a photosensor 61, a mirror device 62, and a plurality of amplifiers 63.

[0037] FIG. 5 is a block diagram showing the configuration of the optical sensor 61, the mirror device 62, and the amplifier 63 of the lighting device 1.

[0038] The optical sensor 61 detects a portion of the light emitted from the phosphor 4a as detection light L3 and outputs a detection signal s0. The optical sensor 61 is a light detection element such as a photodiode, and outputs a detection signal s0 according to the amount of the received detection light L3.

[0039] As shown in Fig. 5, the optical sensor 61 is disposed on the side of the phosphor 4a and receives light emitted in a direction different from the emission direction of the illumination light L2. For example, the detection light L3 is light leaking in a direction perpendicular to the incident direction when the light is input to the phosphor 4a. Note that an optical filter or the like that attenuates light in a wavelength band other than the wavelength band of the detection light L3 may be disposed on the optical path of the detection light L3 from the phosphor 4a to the optical sensor 61. The optical sensor 61 outputs a detection signal s0 according to the amount of light of the detection light L3 to the mirror device 62.

[0040] The mirror device 62 outputs a plurality of output signals s1, s2, and s3 based on the detection signal s0 output from the optical sensor 61. The mirror device 62 is a current mirror circuit that replicates a current using an active element. The mirror device 62 outputs a plurality of output signals s1 to s3 that have the same current value as the detection signal s0. In the example shown in FIG. 5, one detection signal s0 is input to the mirror device 62, and three output signals s1 to s3 are output from the mirror device 62.

[0041] The amplifier 63 is a circuit that amplifies the output signals s1 to s3 output by the mirror device 62. In this embodiment, the amplifier 63 has a current amplifier, a resistor, etc., and amplifies the photocurrent output by the mirror device 62, converts the amplified photocurrent into a voltage, and outputs the voltage signal. The amplified signal output by the amplifier 63 is a voltage signal, and the greater the amount of detection light L3, the greater the value of the photocurrent and the higher the voltage value of the amplified signal. In the example shown in Fig. 5, three amplifiers 63a, 63b, and 63c are shown as the amplifier 63.

[0042] Each of the amplifiers 63a to 63c has a different gain. The amplifiers 63a to 63c amplify the output signals s1 to s3 with different gains and output the amplified signals sa, sb, and sc. The first amplifier 63a of the amplifiers 63 has a first gain, the second amplifier 63b has a second gain lower than the first gain, and the third amplifier 63c has a third gain lower than the second gain. In other words, the second gain is higher than the third gain, and the first gain is higher than the second gain.

[0043] Fig. 6 is a diagram showing the relationship between the amount of detection light L3 detected by the optical sensor 61 and the signal levels of the amplified signals sa to sc. The horizontal axis of Fig. 6 represents the amount of detection light L3, and the vertical axis represents the signal levels of the amplified signals sa to sc. The signal levels are expressed in voltage values.

[0044] 6, the signal level of the amplified signal sa increases linearly from 0 as the amount of detection light L3 increases from 0 (zero). When the amount of detection light L3 exceeds a predetermined amount, the signal level becomes constant at the saturation voltage value. The same is true for the amplified signals sb and sc.

[0045] For example, the first gain of the first amplifier 63a and the second gain of the second amplifier 63b are set so that the amplified signal sb by the second amplifier 63b changes linearly when the amplified signal sb by the first amplifier 63a is saturated. Also, the second gain of the second amplifier 63b and the third gain of the third amplifier 63c are set so that the amplified signal sc by the third amplifier 63c changes linearly when the amplified signal sb by the second amplifier 63b is saturated.

[0046] Further, the gains of the amplifiers 63 are set so that when the signal levels of the amplified signals sa to sc are equal to or less than a first threshold Vth1, which is a predetermined threshold, at least two amplified signals are present for a given amount of light x1 of the detection light L3, so that the amplified signals sa to sc are not too far apart from each other in the horizontal direction. For example, in FIG. 6, the first gain and the second gain are set so that the amplified signals sa and sb are present for a given amount of light x1 of the detection light L3. The first threshold Vth1 is a value set from a signal level range in which the amplified signals sa to sc change linearly with respect to the amount of light of the detection light L3. That is, the first threshold Vth1 is set to a value smaller than the saturation voltage value shown in FIG. 6.

[0047] In addition, the gains of the multiple amplifiers 63 may be set so that at least two amplified signals are present for a given amount of detection light L3 when the signal level of the amplified signals sa to sc is equal to or lower than a first threshold Vth1 and equal to or higher than a second threshold Vth2 which is a threshold smaller than the first threshold Vth1, i.e., when the signal level is within a given range.

[0048] The detection signal s0 output from the optical sensor 61 in this manner is duplicated by the mirror device 62 into a plurality of output signals s1 to s3, and then amplified by the amplifier 63 as a plurality of amplified signals sa to sc with different magnifications, which are then output to the abnormality determination unit .

[0049] [Abnormality determination section] The abnormality determination unit 56 determines whether or not there is an abnormality in the lighting device 1. The abnormality determination unit 56 monitors the amplified signals sa to sc output from the detection circuit 60, and determines whether or not there is an abnormality in at least one of the phosphor 4a and the excitation source 6. In the example shown in Fig. 5, a plurality of amplified signals sa to sc generated by a plurality of amplifiers 63a to 63c are constantly output to the abnormality determination unit 56. Therefore, there is no need to switch the gain of the amplifier circuit as in the conventional technology.

[0050] The abnormality determination unit 56 of this embodiment determines whether or not an abnormality exists based on the amplified signal having the maximum signal level among the amplified signals sa to sc whose signal levels for the amount of detection light L3 are equal to or lower than a first threshold value Vth1. In the example shown in Fig. 6, the abnormality determination unit 56 selects the amplified signal sa having the maximum signal level for the amount of light x1 of the detection light L3, and determines whether or not an abnormality exists based on this amplified signal sa.

[0051] The abnormality determination unit 56 may determine whether or not an abnormality exists based on the ratio of the signal levels of the amplified signal when the light in the wavelength band of the excitation light L1 is used as the detection light L3, and the amplified signal when the light in the wavelength band of the fluorescence obtained by wavelength conversion of the excitation light L1 by the phosphor 4a is used as the detection light L3. For example, when the amplified signal when the excitation light L1 is used as the detection light L3 is used as the denominator and the amplified signal when the fluorescence is used as the detection light L3 is used as the numerator, the abnormality determination unit 56 may determine that an abnormality has occurred in the phosphor 4a when the ratio of the signal levels of the two amplified signals is smaller than a predetermined ratio range. The abnormality determination unit 56 may also determine that an abnormality has occurred in the excitation source 6 when the ratio of the signal levels of the two amplified signals is larger than a predetermined range. To use the excitation light L1 as the detection light L3, for example, an optical filter that transmits the wavelength of the excitation light L1 is disposed on the optical path between the phosphor 4a and the optical sensor 61. The fluorescence can be used as the detection light L3, for example, by disposing an optical filter that transmits the wavelength of the fluorescence on the optical path between the phosphor 4a and the optical sensor 61.

[0052] Furthermore, the abnormality determination unit 56 may determine the presence or absence of an abnormality based on whether or not the rate of decrease in the signal level of the selected amplified signal is greater than a predetermined threshold. For example, the abnormality determination unit 56 may compare the signal level calculated based on the current detection light L3 with the signal level acquired immediately before, and determine that an abnormality has occurred in the excitation source 6 or the phosphor 4a if the rate of decrease in the signal level is equal to or less than a predetermined threshold. The predetermined threshold for the rate of decrease in the signal level of the amplified signal may be, for example, about 50%.

[0053] [Output control circuit] The output control circuit 58 controls the power supply circuit 51 and the light source switching unit 54 to control the current supplied to each light emitting element of the excitation source 6. More specifically, the output control circuit 58 adjusts the drive current I1 by controlling the power supply circuit 51. That is, the output control circuit 58 has a dimming function of adjusting the amount of excitation light L1 by making the drive current I1 variable.

[0054] Furthermore, in this embodiment, when the abnormality determination unit 56 determines that an abnormality has occurred in the lighting device 1, more specifically, when it determines that an abnormality has occurred in the phosphor 4a or the excitation source 6, the output control circuit 58 stops the supply of current to the excitation source 6.

[0055] As described above, the output control circuit 58 and the abnormality determination unit 56 are configured by the controller 5c. The controller 5c includes, for example, a control integrated circuit (IC) and a computer system. The computer system includes, as its main hardware configuration, a processor that operates according to a program. The type of the processor is not limited as long as it can realize each function of the controller 5c by executing the program.

[0056] Thus, the lighting device 1 of this embodiment includes an excitation source 6 that emits excitation light L1, a phosphor 4a that receives the excitation light L1 and emits fluorescence, an optical sensor 61 that uses at least one of the excitation light L1 and the fluorescence as detection light L3 and outputs a detection signal s0 based on the detection light L3, a mirror device 62 that outputs a plurality of output signals s1 to s3 based on the detection signal s0, a plurality of amplifiers 63 that amplify the plurality of output signals s1 to s3 with different gains and output a plurality of amplified signals sa to sc, and an abnormality determination unit 56 that determines the presence or absence of an abnormality based on the amplified signal with the maximum signal level among the amplified signals sa to sc, whose signal levels for the plurality of amplified signals sa to sc relative to the amount of light of the detection light L3 are equal to or lower than a predetermined threshold Vth1.

[0057] According to this configuration, it is possible to determine whether or not an abnormality exists by using an amplified signal suitable for determining whether or not an abnormality exists from among a plurality of amplified signals amplified with different gains. This eliminates the need to switch the gain of the amplifier, and it is possible to prevent the occurrence of a period during which an abnormality in the lighting device 1 cannot be detected due to gain switching. This allows the determination of whether or not an abnormality exists in the lighting device 1 to be performed in a timely manner.

[0058] [2. Operation of lighting device] The operation of the lighting device 1 will now be described.

[0059] First, when AC power from the input power source P1 is input to the lighting device 1, the output control circuit 58 controls the power supply circuit 51 to supply a drive current I1 to the excitation source 6. The multiple light emitting elements 6a to 6d of the excitation source 6 emit blue excitation light L1 due to the drive current I1. The excitation light L1 passes through the optical member 7 and the light guiding member 3 and reaches the phosphor 4a. The phosphor 4a generates white light (wavelength-converted light) from the blue excitation light L1. The phosphor 4a irradiates most of the white light into the illumination space as illumination light L2. A part of the white light reaches the optical sensor 61 of the detection circuit 60 as detection light L3.

[0060] The detection light L3 is the same white light as the illumination light L2 that is actually irradiated into the illumination space, and contains information about the amount of the illumination light L2. That is, the greater the amount of the illumination light L2, the greater the amount of the detection light L3. Therefore, the greater the amount of the illumination light L2, the higher the voltage value of the amplified signal sa, and the smaller the amount of the illumination light L2, the lower the voltage value of the amplified signal sa. That is, information about the amount of the illumination light L2 is fed back to the lighting device 5 as the detection light L3.

[0061] The output control circuit 58 monitors the amount of excitation light L1 emitted by the excitation source 6 based on the voltage value of the amplified signal sa. The output control circuit 58 controls the power supply circuit 51 so that the voltage value of the amplified signal sa coincides with the target voltage value, thereby performing feedback control to make the drive current I1 coincide with the target current. The target voltage value may be a predetermined fixed value or a variable value corresponding to a dimming signal received from the outside. The output control circuit 58 can perform dimming control by making the target voltage value variable.

[0062] In this embodiment, a plurality of output signals s1 to s3 are generated based on a detection signal s0 output from the optical sensor 61 by receiving the detection light L3. The plurality of output signals s1 to s3 are then amplified with different gains to generate a plurality of amplified signals sa to sc. Then, among the amplified signals sa to sc whose signal levels for the amount of detection light L3 are equal to or lower than a predetermined threshold Vth1, the presence or absence of an abnormality is determined based on the amplified signal whose signal level is the maximum.

[0063] According to this configuration, it is possible to determine whether or not there is an abnormality by using an amplified signal suitable for determining whether or not there is an abnormality from among the multiple amplified signals sa to sc amplified with different gains. This eliminates the need to switch the gain of the amplifier, and it is possible to prevent the occurrence of a period during which it is not possible to detect an abnormality in the lighting device 1 due to gain switching. This allows the determination of whether or not there is an abnormality in the lighting device 1 to be performed at the appropriate time.

[0064] [3. Endoscope device equipped with illumination device] An endoscope apparatus equipped with the above-mentioned illumination device 1 will be described.

[0065] FIG. 7 is a schematic diagram showing the configuration of an endoscope apparatus 90 including the illumination device 1 according to the embodiment.

[0066] The endoscope device 90 includes an illumination device 1 and an observation device 91. The illumination device 1 has the same configuration as in the above embodiment.

[0067] The observation device 91 is a device for observing a subject. The observation device 91 has an objective optical system 92 provided in an exposed state near the phosphor 4a, a CCD (Charge Coupled Device) 93 which is an imaging element provided at an image forming position of the objective optical system 92, a video signal processing circuit 94 provided near the light source device 2, and a signal cable 95 which connects the CCD 93 and the video signal processing circuit 94. In the observation device 91, an observation image of the subject formed by the objective optical system 92 is converted into an electric signal by the CCD 93 and transmitted as an image signal by the signal cable 95. The transmitted image signal is converted and processed by the video signal processing circuit 94 into a video signal, and is displayed as an image on a monitor (not shown) connected to the observation device 91. In this endoscope device 90, the same effect as that of the above-mentioned illumination device 1 can be obtained.

[0068] 7 shows an example in which the excitation light L1 is guided to the vicinity of the tip of the endoscope device 90 by the light-guiding member 3 and then converted into illumination light L2, but the present invention is not limited to this. For example, it is also possible to guide the illumination light L2 converted from the excitation light L1 to the tip of the endoscope device 90 by the light-guiding member 3. By using a structure that guides the illumination light L2, it is no longer necessary to install a sensor or the like near the tip of the endoscope device 90, and it is possible to reduce the diameter of the endoscope.

[0069] [4. Effects, etc.] As described above, the lighting device 1 of this embodiment includes an excitation source 6 that emits excitation light L1, a phosphor 4a that receives the excitation light L1 and emits fluorescence, an optical sensor 61 that uses at least one of the excitation light L1 and the fluorescence as detection light L3 and outputs a detection signal s0 based on the detection light L3, a mirror device 62 that outputs a plurality of output signals s1 to s3 based on the detection signal s0, a plurality of amplifiers 63 that amplify the plurality of output signals s1 to s3 with different gains and output a plurality of amplified signals sa to sc, and an abnormality determination unit 56 that determines the presence or absence of an abnormality based on the amplified signal with the maximum signal level among the amplified signals sa to sc, whose signal levels for the amount of light of the detection light L3 are equal to or lower than a predetermined threshold Vth1.

[0070] According to this configuration, it is possible to determine whether or not there is an abnormality by using an amplified signal suitable for determining whether or not there is an abnormality from among the multiple amplified signals sa to sc amplified with different gains. This eliminates the need to switch the gain of the amplifier, and it is possible to prevent the occurrence of a period during which it is not possible to detect an abnormality in the lighting device 1 due to gain switching. This allows the determination of whether or not there is an abnormality in the lighting device 1 to be performed at the appropriate time.

[0071] Furthermore, the abnormality determination section 56 may determine whether or not there is an abnormality in at least one of the excitation source 6 and the phosphor 4a, based on the amplified signal with the maximum signal level.

[0072] This configuration can prevent the occurrence of a period during which an abnormality in the excitation source 6 or the phosphor 4a cannot be detected due to switching of the gain of the amplifier, thereby enabling the presence or absence of an abnormality in the illumination device 1 to be determined in a timely manner.

[0073] Furthermore, the abnormality determination section 56 may determine the presence or absence of an abnormality based on the ratio of the signal levels of the amplified signal when the excitation light L1 is used as the detection light L3 and the amplified signal when the fluorescence is used as the detection light L3.

[0074] According to this configuration, it is possible to timely determine whether or not there are abnormalities in both the excitation source 6 and the phosphor 4a.

[0075] Furthermore, the mirror device 62 may be a current mirror circuit, and may output a plurality of output signals s1 to s3 having the same current value as the detection signal s0.

[0076] According to this configuration, the presence or absence of an abnormality can be determined using the multiple output signals s1 to s3. This eliminates the need to switch the gain of the amplifier, and can prevent the occurrence of a period during which an abnormality in the lighting device 1 cannot be detected due to gain switching. This allows the presence or absence of an abnormality in the lighting device 1 to be determined in a timely manner.

[0077] Furthermore, a first amplifier 63a of the multiple amplifiers 63 has a first gain, and a second amplifier 63b has a second gain lower than the first gain, and the first gain and the second gain may be set such that when the amplified signal sa by the first amplifier 63a is saturated, the amplified signal sb by the second amplifier 63b changes linearly.

[0078] According to this configuration, the abnormality determination unit 56 can continuously obtain a plurality of amplified signals, and can select an amplified signal suitable for reading to determine the presence or absence of an abnormality from among the obtained amplified signals, and can determine the presence or absence of an abnormality. This allows the presence or absence of an abnormality in the lighting device 1 to be determined in a timely manner.

[0079] Furthermore, the predetermined threshold value Vth1 may be set from a signal level range in which each of the multiple amplified signals sa to sc changes linearly with respect to the amount of the detection light L3.

[0080] According to this configuration, it is possible to acquire amplified signals with high accuracy, and to select an amplified signal suitable for reading to determine the presence or absence of an abnormality from among the acquired multiple amplified signals, thereby making it possible to timely determine the presence or absence of an abnormality in the lighting device 1.

[0081] Furthermore, the optical sensor 61 may use light emitted in a direction different from the illumination light L2 emitted from the phosphor 4a as the detection light L3.

[0082] This makes it possible to easily obtain the detection light L3 with little attenuation, thereby making it possible to easily determine whether or not there is an abnormality in the lighting device 1.

[0083] The excitation source 6 may also be a laser element.

[0084] According to this, it is possible to determine whether or not there is an abnormality in the lighting device 1 by using the light emitted from the laser element as the excitation light L1.

[0085] Moreover, an endoscope device 90 according to this embodiment may include the above-mentioned illumination device 1 and an observation device 91 for observing a subject.

[0086] This makes it possible to provide an endoscope apparatus 90 equipped with an illumination device 1 capable of timely determining the presence or absence of an abnormality.

[0087] (Other embodiments) Although the lighting devices and the like according to the multiple aspects of the present disclosure have been described based on the embodiments, the present disclosure is not limited to these embodiments. As long as they do not deviate from the spirit of the present disclosure, various modifications conceived by a person skilled in the art to the present embodiments and forms constructed by combining components in different embodiments may also be included within the scope of the present disclosure.

[0088] For example, in the embodiment, the light guiding member 3 is used as the optical system, but the configuration of the optical system is not limited to the light guiding member 3 as long as the excitation light L1 can be incident and the excitation light L1 can be irradiated onto the phosphor 4a. For example, the optical system may be an optical element such as a mirror or a lens. [Explanation of symbols]

[0089] 1 Lighting equipment 4a Phosphor 6. Excitation Source 56 Abnormality determination section 61 Optical Sensor 62 Mirror Device 63, 63a, 63b, 63c Amplifiers 90 Endoscopic Device 91 Observation Equipment L1 excitation light L2 illumination light L3 Detection light s0 Detection signal s1, s2, s3 output signal sa, sb, sc amplified signals Vth1, Vth2 thresholds

Claims

1. an excitation source that emits excitation light; A phosphor that receives the excitation light and emits fluorescence; an optical sensor that detects at least one of the excitation light and the fluorescent light and outputs a detection signal based on the detection light; a mirror device for outputting a plurality of output signals based on the detection signal; a plurality of amplifiers that amplify the plurality of output signals with different gains and output a plurality of amplified signals; an abnormality determination unit that determines whether or not an abnormality exists based on an amplified signal having a maximum signal level among the plurality of amplified signals whose signal levels with respect to the amount of the detection light are equal to or lower than a predetermined threshold value; A lighting device comprising:

2. The abnormality determination unit determines whether or not there is an abnormality in at least one of the excitation source and the phosphor, based on the amplified signal having the maximum signal level.

10. The lighting device of claim 1.

3. The abnormality determination unit determines whether or not an abnormality exists based on a ratio of a signal level of the amplified signal when the excitation light is used as detection light and a signal level of the amplified signal when the fluorescent light is used as detection light.

3. The lighting device according to claim 2 .

4. The mirror device is a current mirror circuit, and outputs the plurality of output signals having the same current value as the detection signal. The lighting device according to any one of claims 1 to 3.

5. a first amplifier of the plurality of amplifiers having a first gain and a second amplifier having a second gain lower than the first gain; The first gain and the second gain are set so that when the signal amplified by the first amplifier is saturated, the signal amplified by the second amplifier changes linearly. The lighting device according to any one of claims 1 to 4.

6. The predetermined threshold value is set from the signal level range in which each of the plurality of amplified signals changes linearly with respect to the amount of the detected light. The lighting device according to any one of claims 1 to 5.

7. The optical sensor detects light emitted from the phosphor in a direction different from the illumination light. The lighting device according to any one of claims 1 to 6.

8. The excitation source is a laser element. The lighting device according to any one of claims 1 to 7.

9. A lighting device according to claim 8; An observation device for observing a subject; An endoscope apparatus comprising:

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