Lighting device

Abstract

To provide a lighting device that has a simplified configuration and is used for inspection.SOLUTION: A lighting device includes: a plurality of light sources disposed along a predetermined direction; and a plurality of deflection elements disposed while corresponding to each of the light sources to deflect light emitted from the corresponding light sources.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an illumination device for inspection used to detect defects and the like. [Background technology]

[0002] 2. Description of the Related Art Illumination techniques used to detect defects and the like are known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-159487 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned technique for detecting defects and the like has separate optical systems for parallel polarization and vertical polarization, and performs inspection using polarized light having different directions. This conventional technique has a camera for the optical system for parallel polarization and a camera for the optical system for vertical polarization, and the inspection position is different depending on the polarization direction. For this reason, the conventional technique has no choice but to have a complicated optical system.

[0005] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide an illumination device for inspection that can have a simple configuration. [Means for solving the problem]

[0006] The lighting device according to the present invention is characterized by: A plurality of light sources arranged along a predetermined direction; and a plurality of polarizing elements arranged corresponding to each of the plurality of light sources, each polarizing the light emitted from the corresponding light source. Effect of the Invention

[0007] It is possible to provide an illumination device for inspection with a simple configuration. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of a lighting system 10. [Diagram 2] FIG. 1 is a perspective view showing an outline of the configuration of a lighting device 100. [Diagram 3] 1 is a schematic diagram showing the configuration of an illumination device 100 and an outline of an optical path. [Figure 4] 1 is a side view showing the arrangement relationship between an LED substrate 120, an LED 122, and a polarizing plate 130. FIG. [Diagram 5] 1 is a side view showing the arrangement relationship between an LED substrate 120, a plurality of LEDs 122, and polarizing plates 130A to D, the positional relationship between a center O1 of an LED 122 and a center O2 of polarizing plates 130A to D, and the corresponding relationship with the polarization direction. [Figure 6] 4 is a time chart showing a specific example of light emission control. [Figure 7] 4 is a time chart showing a specific example of light emission control. [Figure 8] 4 is a time chart showing a specific example of light emission control. [Figure 9] 4 is a time chart showing a specific example of light emission control. [Figure 10] 4 is a time chart showing a specific example of light emission control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <<<<<Details of the implementation form>>>> Hereinafter, an embodiment will be described with reference to the drawings.

[0010] <<<Direction>>> <Longitudinal direction, length direction, ±Y direction> This refers to the longitudinal direction of the lighting device 100 and the housing 110.

[0011] <Short direction, width direction, ±X direction> The direction perpendicular to the longitudinal direction.

[0012] <Up / down direction, vertical direction, height direction, ±Z direction> It is a direction parallel to gravity, that is, a direction parallel to the string that suspends the object, and a direction perpendicular to the horizontal plane.

[0013] Fig. 1 is a perspective view showing the external appearance of a lighting system 10. Fig. 2 is a perspective view showing an outline of the configuration of a lighting device 100. Fig. 3 is a schematic diagram showing an outline of the configuration of the lighting device 100 and the optical path.

[0014] <<<Lighting System 10>>> As shown in FIG. 1, the lighting system 10 mainly includes a lighting device 100, a power supply device 200, and a harness 300.

[0015] <<Power supply 200>> The power supply device 200 supplies source power to the lighting device 100. The power supply device 200 stabilizes the source power supplied to the lighting device 100. The power supply device 200 mainly includes a control unit 210 and a communication interface 220.

[0016] <Control unit 210> The control unit 210 includes a processor (such as a CPU (Central Processing Unit)), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown).

[0017] <Processor> The processor executes various processes for controlling the power supply voltage of the lighting device 100, which will be described later.

[0018] <rom> The ROM stores various programs and constants for executing various processes (not shown).

[0019] <ram> RAM temporarily stores values ​​such as variables used when a program is executed.

[0020] <Communication Interface 220> The communication interface 220 receives a trigger signal emitted from a camera (not shown). The camera is an imaging device for capturing an image of an illumination target area IR (see FIG. 3) of an illumination target object IO. In response to the trigger signal emitted from the camera, a light emission designation signal for designating an LED to emit light is output to the illumination device 100. In response to the trigger signal emitted from the camera, it is possible to control the timing at which light is emitted from the illumination device 100, the designation of the LED 122 to emit light, and the like.

[0021] <<Harness 300>> The harness 300 is a bundle of conductive wires for electrically connecting the power supply device 200 and the lighting device 100. The harness 300 has a plurality of conductive wires. The harness 300 transmits and receives control signals, detection signals, and the like between the power supply device 200 and the lighting device 100. Furthermore, the harness 300 supplies driving power from the power supply device 200 to the lighting device 100. The length of the harness 300 can be set to a desired length depending on the environment of the installation location, etc. For example, the length of the harness 300 may be up to about 50 meters.

[0022] <<Lighting device 100>> As shown in Fig. 2, the lighting device 100 has an elongated shape as a whole. The lighting device 100 emits illumination light. The lighting device 100 illuminates an illumination target area IR (see Fig. 3) of an illumination object IO with the illumination light. The illumination target area IR is mainly an area on the surface of the illumination object IO.

[0023] The lighting device 100 mainly includes a housing 110, an LED substrate 120, a polarizing plate 130, and a condenser lens 140.

[0024] <Case 110> The housing 110 mainly houses a plurality of LED substrates 120 and a condenser lens 140. The housing 110 defines the outer shape of the approximate lighting device 100. The housing 110 only needs to house a plurality of LED substrates 120, a polarizing plate 130, and a condenser lens 140 so that the lighting device 100 can function.

[0025] The housing 110 is formed by extrusion molding of a metal such as aluminum. The housing 110 may be composed of resin or the like as long as it can maintain strength not only for metal. The housing 110 has an elongated rectangular parallelepiped shape. The housing 110 has a bottom surface portion and side surface portions facing each other with the bottom surface portion interposed therebetween. The bottom surface portion and the side surface portions have an elongated shape.

[0026] <Opening 112> The housing 110 has an opening 112 which is a gap. The opening 112 is formed along the longitudinal direction of the housing and has an elongated shape. The opening 112 is formed at the upper end portions of the side surface portions facing each other. The opening 112 is a through hole or a gap through which light passes. Illumination light is emitted from the opening 112. The opening 112 may be covered with a light-transmitting member such as glass or resin.

[0027] As will be described later, the plurality of LED substrates 120 are arranged along a virtual straight line L1 (see FIGS. 2 and 3) such that the adjacent LED substrates 120 are in close contact with each other along the longitudinal direction (Y direction) of the housing 110. The light emitted from the LED 122 becomes approximately linear light and is emitted from the opening 112.

[0028] <<Optical System>> The optical system of the lighting device 100 is mainly constituted by the LED substrate 120, the polarizing plate 130, and the condenser lens 140. As shown in FIGS. 2 and 3, the LED substrate 120, the polarizing plate 130, and the condenser lens 140 are arranged at predetermined positions.

[0029] <LED Substrate 120> The LED substrate 120 has a thin, elongated shape. The LED substrate 120 is mainly made of a metallic substrate such as an aluminum substrate or a copper substrate. On the LED substrate 120, a plurality of LEDs 122 are arranged linearly along the longitudinal direction. For example, 56 LEDs 122 are provided on one LED substrate 120.

[0030] A conductor pattern for supplying power to the LEDs 122, a conductor pattern for controlling the LEDs 122, and the like are formed on the LED substrate 120. The light emitted from the LEDs 122 can emit long light from the opening 112. The light emitted from the opening 112 can illuminate a long area.

[0031] When multiple LED boards 120 are provided, the multiple LED boards 120 are arranged along the longitudinal direction of the housing 110. That is, the multiple LED boards 120 are arranged along the imaginary straight line L1. Note that the multiple LED boards 120 may be arranged in multiple rows of LEDs 122 in the longitudinal direction, rather than only in one row. In this manner, light can be emitted along the longitudinal direction of the housing 110.

[0032] <led122> The LED 122 emits light of a predetermined wavelength. For example, the LED 122 may be selected from visible light, ultraviolet light, infrared light, or the like, depending on the object to be illuminated, the contents of the inspection, and the like.

[0033] <Control circuit 124> The control circuit 124 controls the light emission of the LED 122. The control circuit 124 controls the brightness of the LED 122, etc. The control circuit 124 has a processor (CPU (Central Processing Unit) etc.), a ROM (Read Only Memory), a RAM (Random Access Memory) etc. (not shown). The processor executes various processes for controlling the brightness of the LED 122, etc. The ROM stores various programs and constants for executing various processes (not shown). The RAM temporarily stores values ​​such as variables used when a program is executed.

[0034] In the above example, the control circuit 124 is provided on the LED board 120, but the control circuit 124 may be provided on the power supply device 200.

[0035] <<Polarizing plate 130>> Fig. 4 is a side view showing the arrangement relationship between the LED substrate 120, the LEDs 122, and the polarizing plate 130. Fig. 5 is a side view showing the arrangement relationship between the LED substrate 120, the multiple LEDs 122, and the multiple polarizing plates 130.

[0036] The polarizing plate 130 is an optical element that transmits light that is polarized (vibrates) in a predetermined direction among the light that is incident on the polarizing plate 130. For example, when non-polarized light (unpolarized light) is incident on the polarizing plate 130, the polarizing plate 130 transmits only linearly polarized light (light that vibrates in a predetermined direction). Polarization means that the vibration direction of light is biased in a specific direction due to natural reflection on the surface of an object. In other words, polarized light means light that vibrates only in a specific direction. Polarized light has two types of information: the polarization direction (vibration direction) and the polarization degree (degree of bias in the vibration direction). As will be described later, a camera that captures an illumination object IO illuminated with polarized light can detect the polarization direction and the polarization degree to visualize the surface state of the object, etc.

[0037] The polarizing plate 130 has a thin plate shape. A plurality of polarizing plates 130 are arranged along the plurality of LEDs 122 in association with each of the LEDs 122 . A plurality of polarizing plates 130 are arranged along the longitudinal direction (Y direction) of the housing 110, along an imaginary straight line L3 (see FIGS. 2 and 3) such that adjacent polarizing plates 130 are in close contact with each other. Since the adjacent polarizing plates 130 are arranged so as to be in close contact with each other, the light emitted from the LEDs 122 always enters the polarizing plates 130 and is polarized.

[0038] As shown in Fig. 4, one polarizing plate 130 is disposed so as to cover one corresponding LED 122. Specifically, as shown in Figs. 3 and 4, one polarizing plate 130 and one corresponding LED 122 are disposed such that a center O1 of the LED 122 and a center O2 of the polarizing plate 130 coincide with each other in the longitudinal direction. The polarizing plate 130 is disposed so as to be spaced a distance d from the corresponding LED 122. In other words, the distance between the polarizing plate 130 and the corresponding LED 122 is the distance d.

[0039] 2 and 3, the plane on which the multiple polarizing plates 130 extend is parallel to the plane on which the multiple LED substrates 120 extend. That is, the plane on which the multiple polarizing plates 130 extend is arranged parallel to a straight line (a straight line parallel to the virtual straight line L1) connecting the emission surfaces of the multiple LEDs 122.

[0040] The polarizing plate 130 has a size according to the size of the LEDs 122, the interval between adjacent LEDs 122, and the like. Specifically, the length W of the polarizing plate 130 in the longitudinal direction corresponds to the size of the LEDs 122 in the longitudinal direction, the interval between adjacent LEDs 122 in the longitudinal direction, and the like.

[0041] The polarizing plate 130 includes four types of polarizing plates 130A to 130D having different polarization directions (see FIG. 5). For example, the polarizing plate 130A is a first polarizing plate that transmits a first linearly polarized light having a first polarization direction, for example, 0 degrees. The polarizing plate 130B is a second polarizing plate that transmits a second linearly polarized light having a second polarization direction, for example, 45 degrees. The polarizing plate 130C is a third polarizing plate that transmits a third linearly polarized light having a third polarization direction, for example, 90 degrees. The polarizing plate 130D is a fourth polarizing plate that transmits a fourth linearly polarized light having a fourth polarization direction, for example, 135 degrees.

[0042] With this configuration, one LED 122 can be associated with one polarizing plate 130. By turning on one LED 122, one polarizing plate 130 can emit polarized light in one polarization direction corresponding to one polarizing plate 130. Note that the above-mentioned polarization direction is an example, and other polarization directions may be used. Also, at least two of the four types of polarizing plates 130A to D may be appropriately combined.

[0043] The four types of polarizing plates 130A to 130D have the same shape and size. When there is no need to distinguish between the four types of polarizing plates 130A to 130D, they will be simply referred to as polarizing plates 130. Furthermore, the four types of polarizing plates 130A to 130D may have different shapes and sizes.

[0044] The four types of polarizing plates 130A to 130D are arranged such that the polarization directions of adjacent ones are different from each other. The polarizing plate 130 can be composed of two or more types of polarizing plates that transmit linearly polarized light having at least two different polarization directions. The four types of polarizing plates 130A to 130D are arranged periodically (having periodicity). The four types of polarizing plates 130A to 130D are repeatedly arranged in a predetermined order.

[0045] In the above-described example, a configuration in which one polarization direction is associated with one polarizing plate is shown, but a configuration in which a plurality of polarization directions are associated with one polarizing plate may also be used. In this case, one polarizing plate has a plurality of polarization regions, and one polarization direction is associated with one polarization region. In this case, one polarization region corresponds to one polarizing plate in the above-described example.

[0046] <Correspondence between LED122 and polarizing plate 130> An example of the correspondence between LED122 and the polarizing plate 130 is shown below.

[0047] <Correspondence 1> Correspondence 1 is a relationship in which the light of LED122 is of one type and the polarization angles of the polarizing plate 130 are of four types. Specifically, the polarizing plate 130A with a polarization angle of 0° is associated with the LED122W1 that emits white light, the polarizing plate 130B with a polarization angle of 45° is associated with the LED122W2 that emits white light, the polarizing plate 130C with a polarization angle of 90° is associated with the LED122W3 that emits white light, and the polarizing plate 130D with a polarization angle of 135° is associated with the LED122W4 that emits white light.

[0048] <Correspondence 2> Correspondence 2 is a relationship in which the light of LED122 is of one type and the polarization angles of the polarizing plate 130 are of two types. Specifically, the polarizing plate 130A with a polarization angle of 0° is associated with the LED122W1 that emits white light, and the polarizing plate 130C with a polarization angle of 90° is associated with the LED122W3 that emits white light.

[0049] <Correspondence 3> Correspondence relationship 3 is a relationship in which there are four types of light (color, wavelength) of the LEDs 122 and four types of polarization angles of the polarizing plate 130. Specifically, polarizing plate 130A with a polarization angle of 0° is associated with LED 122R emitting red light, polarizing plate 130B with a polarization angle of 45° is associated with LED 122G emitting green light, polarizing plate 130C with a polarization angle of 90° is associated with LED 122B emitting blue light, and polarizing plate 130D with a polarization angle of 135° is associated with LED 122NI emitting near-infrared light.

[0050] <Correspondence 4> Correspondence relationship 4 is a relationship in which there are two types of light (color, wavelength) of the LED 122 and two types of polarization angles of the polarizing plate 130. Specifically, polarizing plate 130A with a polarization angle of 0° is associated with LED 122R emitting red light, and polarizing plate 130C with a polarization angle of 90° is associated with LED 122B emitting blue light.

[0051] By selectively causing the LEDs 122 to emit light, the light from the LEDs 122 can be incident on only the polarizing plate 130 corresponding to the emitted LEDs 122, polarized, and emitted as polarized light.

[0052] <<<Layout (positional relationship)>>> 4 and 5, the LED 122 has a light distribution angle θ. The light distribution angle θ of the LED 122 is the angle from the reference angle at which the amount of light decreases to 50% (I1 in FIG. 4) when the angle at which the maximum amount of light emitted from the LED 122 is 100% is set as the reference angle (I0 in FIG. 4). For example, if the range of angles at which the amount of light is 50% or more is ±60 degrees from the reference angle, the light distribution angle θ is 60 degrees. The amount of light refers to the total amount of light flux passing through a certain surface within a certain period of time.

[0053] As shown in FIGS. 4 and 5, when the distance (spacing) between adjacent LEDs 122 is p and the distance between the LEDs 122 and the polarizing plate is d, an arrangement in which the following relationship holds is preferable. d≦(p / 2) / tanθ=p / (2tanθ)

[0054] By satisfying this relationship, light emitted from the LED 122 with a light distribution angle θ or less can be made to enter the corresponding polarizing plate 130. That is, all of the light emitted from the LED 122 that is included in an angle where the amount of light is 50% or more can be made to enter the corresponding polarizing plate 130. In this way, the light that substantially determines the brightness of the light emitted from the LED 122 can be made to enter the corresponding polarizing plate 130 and polarized. In other words, the light emitted from the LED 122 can be made to enter only the corresponding polarizing plate 130. Specifically, the light of the LED 122 is made to enter the polarizing plate 130 arranged directly above it. The light emitted from the LED 122 is made to enter the corresponding polarizing plate 130 without leakage. Furthermore, the light emitted from the LED 122 can be prevented from entering a non-corresponding polarizing plate 130 adjacent to the corresponding polarizing plate 130.

[0055] <Light-reducing materials, opaque materials> As described above, adjacent polarizing plates 130 are provided in close contact with each other without any gaps, but a light-reducing member, a non-transmissive member, or the like may be provided at the boundaries or gaps between adjacent polarizing plates 130. The polarizing plates 130 can prevent unpolarized light from being emitted.

[0056] <<Condenser lens 140>> The condenser lens 140 condenses the light emitted from the LED 122. The condenser lens 140 is made of acrylic or glass and has light-transmitting properties. The condenser lens 140 has a long cylindrical shape and is also called a rod lens. Any other shape may be used to condense light.

[0057] The condensing lens 140 is disposed at a position separated from the multiple LEDs 122. The condensing lens 140 is disposed such that an imaginary straight line L1 indicating the arrangement of the centers O1 of the multiple LEDs 122, an imaginary straight line L3 indicating the arrangement of the centers O2 of the multiple polarizing plates 130, and a central axis L2 of the condensing lens 140 are parallel to each other.

[0058] The condenser lens 140 is sandwiched between a plurality of lens stays (for example, four lens stays) (not shown) and fixed at a certain position on the housing 110.

[0059] <<<Other configurations>>> <Diffuser 150> The diffuser 150 diffuses the incident light to make the brightness closer to uniform. A minute lens array is formed on the surface of the diffuser 150. Long groove-shaped regions and long ridge-shaped regions are alternately formed adjacent to each other on the surface of the diffuser 150. The groove-shaped regions and ridge-shaped regions create minute random irregularities repeatedly, and the minute irregularities function as a minute lens array. The diffuser 150 refracts and diffuses the incident light at a desired diffusion angle (light distribution angle) by the diffusion function of the lens array. The diffuser 150 diffuses light more strongly in another direction than in a certain direction (elliptical diffusion). Specifically, the diffuser 150 diffuses light more strongly in the length direction (longitudinal direction) than in the width direction (short direction).

[0060] The diffuser 150 may be provided between the polarizing plate 130 and the LED 122. The diffuser 150 may also be provided between the condenser lens 140 and the opening 112. The diffuser 150 may also be provided in the opening 112.

[0061] <<<Light Emission Control Processing>>> As described above, the trigger signal for controlling the light emission is output from a camera for photographing the illumination target area IR of the illumination target IO. The camera has a desired spectral characteristic. For example, the camera has a response to a first wavelength region and a response to a second wavelength region different from the first wavelength region separately. The camera has a response to a red wavelength region and a response to a green wavelength region separately. Even if the camera photographs light of the first wavelength region and light of the second wavelength region simultaneously, the image by the light of the first wavelength region and the image by the light of the second wavelength region can be separated. The response to the first wavelength region and the response to the second wavelength region are preferably such that they do not have a predetermined degree of overlap (color crosstalk) so that the photographed images can be separated. The camera can be a color camera or a monochrome camera having standard spectral characteristics, a prism spectroscopic color camera, or the like.

[0062] The illumination device 100 emits polarized light. The polarized light emitted from the illumination device 100 illuminates the illumination object IO. As described above, polarized light has two types of information: the polarization direction (vibration direction) and the degree of polarization (degree of bias in the vibration direction). By capturing an image of the illumination object IO illuminated with polarized light using a camera, the camera can detect the polarization direction and the degree of polarization, and visualize the detailed surface condition of the object that is difficult to recognize in the absence of polarization. This makes it possible to perform appearance inspection, stress recognition, detection of specific objects, and the like.

[0063] The trigger signal may be outputted not only from the camera but also from the control unit 210. When the trigger signal is outputted from the control unit 210, the trigger signal is outputted to both the lighting device 100 and the camera. The trigger signal from the control unit 210 enables the lighting device 100 to determine the timing of emitting light, and enables the camera to determine the timing of capturing an image.

[0064] <<Light Emission Control Modes>> Five types of control are shown below as examples of light emission control. Fig. 6 is a time chart showing light emission control 1. Fig. 7 is a time chart showing light emission control 2. Fig. 8 is a time chart showing light emission control 3. Fig. 9 is a time chart showing light emission control 4. Fig. 10 is a time chart showing light emission control 5.

[0065] <Light Emission Control 1> Emission control 1 uses the above-mentioned correspondence relationship 1. That is, emission control 1 uses a configuration in which polarizing plate 130A with a polarization angle of 0° corresponds to LED 122W1 that emits white light, polarizing plate 130B with a polarization angle of 45° corresponds to LED 122W2 that emits white light, polarizing plate 130C with a polarization angle of 90° corresponds to LED 122W3 that emits white light, and polarizing plate 130D with a polarization angle of 135° corresponds to LED 122W4 that emits white light.

[0066] That is, in light emission control 1, polarized light with a polarization angle of 0°, polarized light with a polarization angle of 45°, polarized light with a polarization angle of 90°, and polarized light with a polarization angle of 135° are all emitted at different timings. Polarized light with different polarization angles is separately illuminated onto the illumination target area IR of the illumination target IO, so images with different polarization angles can be acquired and judged separately for each polarization angle, improving the accuracy of detection of foreign objects, defects, etc. In light emission control 1, it is sufficient to photograph the illumination target area IR with a normal monochrome camera. With a simple configuration, foreign objects, defects, etc. can be detected with high accuracy.

[0067] As shown in FIG. 6, LED122W1 emits white light between times T1 and T2. By emitting light from LED122W1, only polarized light with a polarization angle of 0° is emitted from the lighting device, and only the polarized light with a polarization angle of 0° illuminates the lighting target area IR. LED122W2 emits white light between times T3 and T4. By emitting light from LED122W2, only polarized light with a polarization angle of 45° is emitted from the lighting device, and only the polarized light with a polarization angle of 45° illuminates the lighting target area IR. LED122W3 emits white light between times T5 and T6. By emitting light from LED122W3, only polarized light with a polarization angle of 90° is emitted from the lighting device, and only the polarized light with a polarization angle of 90° illuminates the lighting target area IR. LED122W4 emits white light between times T7 and T8. By emitting light from the LED 122W4, only polarized light with a polarization angle of 135° is emitted from the lighting device, and only the polarized light with a polarization angle of 135° illuminates the illumination target area IR.

[0068] After time T9, the LEDs 122W1 to 122W4 are repeatedly caused to emit light in a similar manner to illuminate the illumination target area IR. Depending on the size of the illumination target IO, the LEDs 122W1 to 122W4 are repeatedly used to illuminate the illumination target area IR, thereby making it possible to inspect the entire illumination target IO.

[0069] <Light Emission Control 2> Emission control 2 uses the above-mentioned correspondence relationship 2. That is, emission control 2 uses a configuration in which polarizer 130A with a polarization angle of 0° corresponds to LED 122W1 that emits white light, and polarizer 130C with a polarization angle of 90° corresponds to LED 122W3 that emits white light.

[0070] That is, in light emission control 2, polarized light with a polarization angle of 0° and polarized light with a polarization angle of 90° are emitted at different timings. Polarized light with different polarization angles is separately illuminated onto the illumination target area IR of the illumination target IO, so images with different polarization angles can be acquired and judged separately for each polarization angle, improving the accuracy of detecting foreign objects, defects, etc. In light emission control 1, it is sufficient to photograph the illumination target area IR with a normal monochrome camera. With this simple configuration, foreign objects, defects, etc. can be detected with high accuracy.

[0071] As shown in Fig. 7, LED122W1 emits white light between times T1 and T2. By emitting light from LED122W1, only polarized light with a polarization angle of 0° is emitted from the lighting device, and only polarized light with a polarization angle of 0° illuminates the illumination target area IR. LED122W3 emits white light between times T3 and T4. By emitting light from LED122W2, only polarized light with a polarization angle of 90° is emitted from the lighting device, and only polarized light with a polarization angle of 90° illuminates the illumination target area IR.

[0072] After time T5, the LEDs 122W1 and 122W3 are alternately and repeatedly illuminated in the same manner to illuminate the illumination target area IR. Depending on the size of the illumination target IO, the LEDs 122W1 and 122W3 are alternately and repeatedly illuminated in the illumination target area IR, thereby making it possible to inspect the entire illumination target IO.

[0073] <Light Emission Control 3> Emission control 3 uses the above-mentioned correspondence relationship 3. That is, emission control 3 uses a configuration in which polarizer 130A with a polarization angle of 0° corresponds to LED 122R emitting red light, polarizer 130B with a polarization angle of 45° corresponds to LED 122G emitting green light, polarizer 130C with a polarization angle of 90° corresponds to LED 122B emitting blue light, and polarizer 130D with a polarization angle of 135° corresponds to LED 122NI emitting near-infrared light.

[0074] That is, in light emission control 3, at least some of the polarized light with a polarization angle of 0°, polarized light with a polarization angle of 45°, polarized light with a polarization angle of 90°, and polarized light with a polarization angle of 135° are emitted at overlapping times. Since polarized light with different polarization angles is illuminated onto the illumination target area IR of the illumination target IO at overlapping times, the time required for illumination can be shortened, and detection of foreign objects, defects, and the like can be completed in a short time. In light emission control 3, it is sufficient to capture the illumination target area IR with a camera having the desired spectral characteristics.

[0075] As shown in Fig. 8, LED122R and LED122B simultaneously emit red light and blue light between times T1 and T2. By simultaneously emitting light from LED122R and LED122B, polarized light with a polarization angle of 0° and a polarization angle of 90° is simultaneously emitted from the lighting device, and the polarized light with a polarization angle of 0° and a polarization angle of 90° illuminates the illumination target area IR. LED122G and LED122NI emit green light and near infrared light between times T3 and T4. By simultaneously emitting light from LED122G and LED122NI, polarized light with a polarization angle of 45° and a polarization angle of 135° is simultaneously emitted from the lighting device, and the polarized light with a polarization angle of 45° and a polarization angle of 135° illuminates the illumination target area IR.

[0076] After time T5, the LEDs 122R, G, B, and NI are repeatedly illuminated in the same manner to illuminate the illumination target area IR. Depending on the size of the illumination target IO, the LEDs 122R, G, B, and NI are repeatedly used to illuminate the illumination target area IR, thereby making it possible to inspect the entire illumination target IO.

[0077] <Light Emission Control 4> Emission control 4 uses the above-mentioned correspondence relationship 4. That is, emission control 4 uses a configuration in which polarizer 130A with a polarization angle of 0° corresponds to LED 122R that emits red light, and polarizer 130C with a polarization angle of 90° corresponds to LED 122B that emits blue light.

[0078] That is, in the light emission control 4, polarized light with a polarization angle of 0° and polarized light with a polarization angle of 90° are emitted at an overlapping timing. Since polarized light with different polarization angles is illuminated onto the illumination target area IR of the illumination target IO at an overlapping timing, the time required for illumination can be shortened, and detection of foreign objects, defects, etc. can be completed in a short time. In the light emission control 4, it is sufficient to photograph the illumination target area IR with a camera having the desired spectral characteristics.

[0079] 9, LED122R and LED122B simultaneously emit red light and blue light between times T1 and T2. By causing LED122R and LED122B to emit light simultaneously, polarized light with a polarization angle of 0° and a polarization angle of 90° is simultaneously emitted from the lighting device, and the polarized light with a polarization angle of 0° and a polarization angle of 90° simultaneously illuminates the illumination target area IR.

[0080] The time from T1 to T2 may be a time that allows the entire illumination target IO to be inspected by illuminating the illumination target area IR. Note that the light emission control 4 is a constant-lighting control, with time T1 indicating the start time of the constant lighting and time T2 indicating the end time of the constant lighting. For this reason, the light emission control 4 can be controlled without using a trigger signal.

[0081] <Light Emission Control 5> The light emission control 5 uses the above-mentioned correspondence relationship 3. That is, the light emission control 5 uses a configuration in which the polarizing plate 130A having a polarization angle of 0° corresponds to the LED 122R that emits red light, the polarizing plate 130B having a polarization angle of 45° corresponds to the LED 122G that emits green light, the polarizing plate 130C having a polarization angle of 90° corresponds to the LED 122B that emits blue light, and the polarizing plate 130D having a polarization angle of 135° corresponds to the LED 122NI that emits near-infrared light.

[0082] That is, in the light emission control 5, polarized light with a polarization angle of 0°, polarized light with a polarization angle of 45°, polarized light with a polarization angle of 90°, and polarized light with a polarization angle of 135° are emitted at overlapping times. Since polarized light with different polarization angles is illuminated onto the illumination target area IR of the illumination target IO at overlapping times, the time required for illumination can be shortened, and detection of foreign objects, defects, and the like can be completed in a short time. In the light emission control 5, it is sufficient to photograph the illumination target area IR with a camera having the desired spectral characteristics.

[0083] 9, LED122R, LED122G, LED122B, and LED122NI simultaneously emit red light, green light, blue light, and infrared light between times T1 and T2. By causing LED122R, LED122G, LED122B, and LED122NI to emit light simultaneously, polarized light with polarization angles of 0°, 45°, 90°, and 135° is simultaneously emitted from the lighting device, and the polarized light with polarization angles of 0°, 45°, 90°, and 135° simultaneously illuminates the illumination target area IR.

[0084] The time from T1 to T2 may be a time that allows the entire illumination target IO to be inspected by illuminating the illumination target area IR. Note that the light emission control 5 is a constant-lighting control, with time T1 indicating the start time of the constant lighting and time T2 indicating the end time of the constant lighting. For this reason, the light emission control 5 can be controlled without using a trigger signal.

[0085] <<<<Outline of this embodiment>>>> The outline of this embodiment will be described below. With the illumination device according to this embodiment, polarized light of different polarization states can be selected and emitted from a single illumination device to illuminate an area of ​​a predetermined shape, for example, a long area. Polarized light of different polarization states can be selectively emitted from a single illumination device without preparing multiple illumination devices for emitting polarized light of different polarization states, and an illumination device for inspection with a simplified configuration can be provided.

[0086] <<First feature>> According to the first feature, A plurality of light sources arranged along a predetermined direction; There is provided an illumination device comprising: a plurality of polarizing elements disposed corresponding to each of the plurality of light sources, the polarizing elements polarizing light emitted from the corresponding light sources.

[0087] The illumination device includes a plurality of light sources and a plurality of polarizing elements.

[0088] The multiple light sources are arranged along a predetermined direction. The predetermined direction may be a direction along a straight line or a direction along a curve. The arrangement of the multiple light sources may be appropriately determined depending on the shape and size of the illumination target area. For example, the multiple light sources may be arranged in a straight line or in an arc shape. The multiple light sources may be arranged not only in one row along the predetermined direction, but also in multiple rows along the predetermined direction. That is, the multiple light sources may be arranged in at least one row along the predetermined direction. The multiple rows are preferably parallel to each other. The multiple rows may not be parallel to each other in whole or in part. It is sufficient that the multiple light sources are recognized as being arranged in the predetermined direction as a whole.

[0089] The multiple polarizing elements are arranged corresponding to the multiple light sources, respectively. That is, if the multiple light sources are arranged in a straight line, the multiple polarizing elements are also arranged in a straight line. Also, if the multiple light sources are arranged in an arc, the multiple polarizing elements are also arranged in an arc. The arrangement of the multiple polarizing elements may be appropriately determined depending on the shape and size of the illumination target area.

[0090] In addition, the multiple polarizing elements may be arranged in multiple rows along the predetermined direction, not just in one row. That is, the multiple polarizing elements may be arranged in at least one row along the predetermined direction. It is preferable that the multiple rows are parallel to each other. The multiple rows do not have to be entirely or partially parallel to each other. It is sufficient that the multiple polarizing elements are all recognized as being arranged along the predetermined direction.

[0091] The polarizing element and the light sources can be arranged in one-to-one correspondence, many-to-one correspondence, or one-to-many correspondence. The polarizing element receives light emitted from a corresponding light source, polarizes the incident light, and emits it. That is, the polarizing element does not polarize light emitted from an uncorresponding light source. Note that even if light emitted from an uncorresponding light source is insufficiently bright, it may be polarized. Any light that does not affect the illumination of the illumination object may be used.

[0092] A polarizing element is an element that converts the polarization state. The polarizing element may be any element that can emit polarized light having a polarization state that can be used as illumination light for detecting the surface state of an object. For example, a polarizing plate is an example of a polarizing element. A polarizing plate is a polarizing element that converts light into completely polarized light. Polarized light that a polarizing plate can convert includes linearly polarized light, circularly polarized light, and elliptically polarized light. Any polarized light may be used as long as it is polarized light that can detect the surface state of an object.

[0093] Furthermore, linearly polarized light is preferred as the polarized light. In the case of linearly polarized light, the polarization state refers to the polarization direction, and the polarization direction refers to the direction in which the vibration plane of the linearly polarized light extends. One polarizing plate corresponds to one polarization direction and can emit polarized light of one polarization direction. A polarizing plate capable of emitting polarized light having different polarization directions is arranged. The polarized light having different polarization directions can be selectively emitted. The polarized light having different directions in which the vibration plane of the linearly polarized light extends can be selectively emitted.

[0094] Since a plurality of light sources and a plurality of polarizing elements are arranged in correspondence with each other, by emitting light from a desired light source among the plurality of light sources, only the desired polarized light can be emitted and the illumination target area can be illuminated with the desired polarized light. By inspecting the surface condition, etc., it is possible to easily find foreign matter or defects. In addition, by configuring the light source that emits light among the plurality of light sources to be switched, it is possible to emit polarized light with different polarization directions. By illuminating polarized light with different polarization directions, it is possible to easily find other foreign matter or defects. In this way, it is possible to easily find various foreign matter or defects in the illumination target area.

[0095] <<Second feature>> The second feature is that, in the first feature, The plurality of polarizing elements are arranged along the predetermined direction, Each of the polarizing elements is disposed corresponding to each of the plurality of light sources.

[0096] Each of the polarizing elements corresponds to each of the multiple light sources. That is, the polarizing elements and the light sources are arranged in a one-to-one correspondence. With this configuration, the light emitted from the light source can be accurately incident on the corresponding polarizing element, and the light can be stably polarized to illuminate the illumination target area with the polarized light.

[0097] <<Third feature>> The third feature is that in the second feature, The polarization directions of the polarizing elements adjacent to each other along the predetermined direction are different from each other.

[0098] Since the polarizing elements with different polarization directions are arranged adjacent to each other, it is possible to selectively emit polarized light with a desired polarization direction. With only a single lighting device, it is possible to selectively illuminate an object with polarized light according to the object to be illuminated.

[0099] <<Fourth feature>> The fourth feature is the third feature, The wavelength characteristics of the light sources adjacent to each other along the predetermined direction are different from each other, The plurality of light sources and the plurality of polarizing elements are arranged such that the polarization direction and the wavelength characteristic correspond to each other.

[0100] A plurality of light sources and a plurality of polarizing elements are arranged such that the polarization direction and the wavelength characteristic are associated with each other. For example, one polarization direction is associated with one wavelength characteristic. Specifically, as an example, a polarizing plate with a polarization angle of 0° is associated with a light source that emits red light, a polarizing plate with a polarization angle of 45° is associated with a light source that emits green light, a polarizing plate with a polarization angle of 90° is associated with a light source that emits blue light, and a polarizing plate with a polarization angle of 135° is associated with a light source that emits near-infrared light. In this way, the polarized light in which the polarization direction and the wavelength characteristic are associated with each other is illuminated on the illumination object.

[0101] Polarized light can be received according to the spectral characteristics of a light receiving device such as a camera that captures the illumination object. The spectral characteristics are the degree of overlap of the wavelengths of the received light (color crosstalk). For example, a prism-spectroscopic color camera with little color crosstalk can be used. In other words, even if the light receiving device simultaneously receives light of different wavelengths, if the light receiving device has little color crosstalk, the light can be separated by wavelength for processing. When a light receiving device with such spectral characteristics is used, light of different wavelengths can be emitted simultaneously from the illumination device. By simultaneously emitting light of different wavelengths, the time required for illumination can be shortened, and as a result, the inspection time can be shortened.

[0102] <<Fifth feature>> The fifth feature is the fourth feature, The polarization direction of each of the plurality of polarizing elements is any one of a plurality of polarization directions different from each other, The plurality of polarizing elements are arranged along the predetermined direction in a sequence in which the polarization directions are in a predetermined order, The plurality of light sources are arranged along the predetermined direction in such a manner that the wavelength characteristics are in a predetermined order.

[0103] When using multiple polarizing elements having multiple different polarization directions and multiple light sources having multiple different wavelength characteristics, the correspondence between one polarization direction and one wavelength characteristic can be kept constant, and one polarization direction can be configured as a pair with one wavelength characteristic.

[0104] This simplifies the control of the light emission of the light source and makes it possible to regulate the brightness of the emitted light.

[0105] <<The sixth feature>> The sixth feature is the fifth feature, The predetermined order of the polarization directions and the predetermined order of the wavelength characteristics have periodicity.

[0106] Since a pair of one polarization direction and one wavelength characteristic is arranged periodically, the brightness of the emitted light can be made closer to uniform overall.

[0107] <<<<Scope of embodiment>>>> As described above, the embodiments have been described. However, the description and drawings forming a part of this disclosure should not be understood as being limiting. Various embodiments not described here are included. [Explanation of symbols]

[0108] 10. Lighting System 100 Lighting Equipment 120 LED board 122 LED 130 Polarizing Plate < / ram> < / rom>

Claims

1. A plurality of light sources arranged along a predetermined direction; and a plurality of polarizing elements arranged corresponding to each of the plurality of light sources, each polarizing the light emitted from the corresponding light source.

2. The plurality of polarizing elements are arranged along the predetermined direction, The lighting device according to claim 1 , wherein each of the polarizing elements is disposed corresponding to each of the plurality of light sources.

3. The illumination device according to claim 2 , wherein the polarization directions of the polarizing elements adjacent to each other along the predetermined direction are different from each other.

4. The wavelength characteristics of the light sources adjacent to each other along the predetermined direction are different from each other, The illumination device according to claim 3 , wherein each of the plurality of light sources and each of the plurality of polarizing elements are arranged such that the polarization direction and the wavelength characteristic correspond to each other.

5. The polarization direction of each of the plurality of polarizing elements is any one of a plurality of polarization directions different from each other, The plurality of polarizing elements are arranged along the predetermined direction in a sequence in which the polarization directions are in a predetermined order, The illumination device according to claim 4 , wherein the plurality of light sources are arranged along the predetermined direction in such a manner that the wavelength characteristics are in a predetermined order.

6. The illumination device according to claim 5 , wherein the predetermined order of the polarization directions and the predetermined order of the wavelength characteristics have periodicity.

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