JPH1183465A - Surface inspecting method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface inspecting method and a device therefor, capable of detecting a defect as surface unevenness easily and certainly and also capable of detecting surface defects over the whole area in a short time. SOLUTION: The light emitted from a light source 12 with a wavelength lying in the visible region is trimmed linearly by an optical system 13 and irradiated aslant onto the surface 9a of an LCD 9 as an object to be inspected. An observing system 14 has a CCD photographing device 26 installed over the LCD 9, and if there is no defect as surface unevenness in the part (p) where a linear beam of light R is put incident on the surface 9a of the LCD 9, a defect (q) as surface unevenness is detected depending upon whether diffused beams of light S are detected or not in the region N, which is judged as a dark region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface inspection method and a surface inspection apparatus, and more particularly, to a surface defect of a liquid crystal display (hereinafter, referred to as an LCD) having an irregular size (for example, several The present invention relates to a surface inspection method and apparatus effective for detecting small scratches or dust attached to the order of μm).

[0002]

2. Description of the Related Art For example, in the process of manufacturing an LCD, irregularities such as scratches and dust adhering to the LCD may sometimes occur on the surface thereof. Conventionally, a surface inspection apparatus 1 as shown in FIG. 5 has been used to detect this defect. The optical microscope 2 is arranged above an LCD 9 to be inspected, and a CCD imaging device 3 connected to a monitor 4 is arranged above the optical microscope 2. The optical microscope 2 mainly includes an objective lens 2a, an imaging lens 2b, a beam splitter 2c disposed therebetween, a white light source 2r such as a halogen lamp, and a lens 2d. In the optical microscope 2, the light of the white light source 2r is guided to the beam splitter 2c via the lens 2d. The beam splitter 2c is, so to speak, a half mirror, reflects light from the white light source 2r, irradiates the surface 9a of the LCD 9 disposed below the optical microscope 2 from above, and irradiates the surface 9a of the LCD 9 with the surface 9a. Image of C
The light is transmitted through the CD imaging device 3. That is,
The surface inspection apparatus 1 uses the light from the optical microscope 2
The surface 9a of the CD 9 is illuminated, and the light is again transmitted through the optical microscope 2 by the CCD image pickup device 3 disposed above the light.
The surface 9a of the CD 9 is imaged.

If the surface 9a of the LCD 9 has an irregularity defect such as a flaw or dust attached to the surface, the portion becomes a step and produces a shadow. Project. FIG.
Is the image 4a projected on the monitor 4.
And I and J indicate shadows generated due to unevenness defects. For example, a change in brightness is visually inspected to detect an uneven defect on the surface 9a. Alternatively, an image processing computer 5 is connected to the monitor 4 and a CCD
The image captured by the imaging device 3 is compared with a pre-registered image in the case where there is no defect in the surface state, and the surface 9a is checked.
And irregularities defects are detected.

[0004]

In this conventional method,
The unevenness of the surface 9a of the LCD 9 due to scratches or dust attached to the surface 9a is determined by whether or not a shadow is generated by the illumination light, that is,
This is detected by the decrease in the brightness of that part. For this reason, the unacceptable unevenness defect is constituted by a plurality of layers having different structures having a stepped structure therein, such as a case where the unacceptable unevenness defect is small (for example, smaller than the pixel of the CCD imaging device 3) or an LCD. In the case of the device to be performed, there is a case where it is not possible to distinguish between the shadow due to the step of the internal structure and the surface irregularity defect.
It is difficult to reliably detect unevenness defects on the surface only by enlarging at a magnification of about 1 to 5 times. Therefore,
Conventionally, the surface 9a of the LCD 9 had to be enlarged at a magnification of 10 or more in order to reliably detect the irregularity defect. With such a high magnification, the imaging range of the front surface 9a of the LCD 9, which is taken into the CCD imaging device 3 as an image at a time, that is, the inspection range becomes small.
Therefore, there is a problem that the inspection time for detecting the unevenness defect on the entire surface 9a of the LCD 9 becomes long.

[0005] Further, in the case of a flaw having a depth of about several μm, a dark shadow (a part whose luminance is recognized to be much lower than other parts) cannot be formed. Therefore, in this case, the signal to be determined to be a shadow generated due to the unevenness defect is small,
That is, the noise ratio (S / N ratio) to the signal was poor, and the defect could not be reliably detected. In addition, when an image projected on the monitor 4 is visually inspected for an unevenness defect, there is a problem that an individual difference occurs in an inspection result and a detection error occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and reliably detects unevenness defects such as surface scratches and dust adhesion.
It is another object of the present invention to provide a surface inspection method and apparatus capable of shortening the inspection time.

[0007]

The object of the present invention is to irradiate a part of the inspection surface with light obliquely to the inspection surface, and to form an unacceptable irregularity defect on the inspection surface where the light is incident. If there is, let the light scatter, and this scattered light,
A surface inspection method for detecting a defect on an inspection surface by detecting an area within a dark area having low luminance equal to or less than a predetermined value when there is no irregularity defect in a portion where the light is incident. Solved by

In this way, when there is an irregularity defect on the inspection surface, scattered light having a luminance higher than the predetermined value is detected in a dark area having a low luminance lower than a predetermined value. . That is, since it is possible to reliably detect whether or not scattered light is generated, it is possible to reliably detect the unevenness defect. Further, since the scattered light is uniformly scattered from the irregularity defect portion, the light is detected over a range larger than the size of the irregularity defect formed on the inspection surface with the irregularity defect as a center. In other words, the scattered light generated by the irregularity defect is observed as a range larger than the range of the size of the irregularity defect actually formed on the inspection surface, so that it is easy to detect the irregularity defect on the inspection surface. Therefore, for example, even if the scratch has a depth of about several μm, it can be reliably and easily detected. Further, in order to reliably detect the irregularity defect, it is not necessary to enlarge the inspection surface to a high magnification of 10 times or more as in the related art, and it is possible to shorten the inspection time of the entire inspection surface.

[0009] Further, the above problems are to be solved at least by a light source for generating illumination light and shaping the illumination light into light having a desired shape.
An optical system that allows light to enter a part of the surface of the inspection object in an oblique direction with respect to the surface, and an optical system that emits light when there is no irregularity defect such as scratches or dust on the surface where the light enters. Is provided at a position where the luminance of the surface of the part where light is incident is detected as a dark area having a low luminance of a predetermined level or less, and scattered light generated when the luminance of the surface of the part where light is incident has an irregularity defect. The problem is solved by a surface inspection apparatus including an observation system provided with a detector for detecting. With such a surface inspection apparatus, since the above-described surface inspection method can be performed, even if unacceptable scratches and dust are attached in micro units, they can be easily and reliably detected.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, light is radiated to an inspection surface from an oblique direction. The light is scattered, that is, irregularly reflected. As is well known, if the size of the irregularities on the surface (boundary surface) is equal to or greater than the wavelength of the irradiated light, irregular reflection occurs. Then, light with a condition satisfying this condition is irradiated. If the inspection surface does not have an unevenness defect that is more than the tolerance, the irradiated light is scattered (that is, irregularly reflected) in a region that is detected as a dark region having a low luminance equal to or less than a predetermined value. Is detected. Therefore, if a luminance that is determined to be scattered light is obtained in a dark region having a small luminance equal to or less than a predetermined value, it means that an uneven defect has occurred, and the uneven defect can be easily detected. Also, the scattered light is scattered around the uneven defect, so the scattered light is
This is observed in a region larger than the size of the unevenness defect on the inspection surface. Therefore, even if the size of the irregularity defect is as small as, for example, a micro unit, the irregularity defect can be reliably detected. Further, even if the image of the surface of the inspection object (inspection surface) to be formed on the detector of the observation system is not set to a high magnification of 10 times or more as in the related art, for example, to a low magnification of 0.5 to 5 times, The irregularities can be reliably and easily detected.

Further, as an apparatus for actually performing the surface inspection method, a light source for generating illumination light, a light source for shaping the light into a desired shape, and a part of a surface serving as an inspection surface of an inspection object are provided on the surface. An optical system that is obliquely incident on the optical system, and a portion where light on the detection surface is incident, when there is no irregularity defect larger than an allowable size, the luminance of the portion is a dark region having a low luminance of a predetermined value or less. Any surface inspection apparatus may be used as long as the surface inspection apparatus is provided at a position to be detected and includes an observation system including a detector for detecting scattered light generated when the portion has an irregularity defect.

Further, if the position of the defect is detected by relatively moving the light irradiating a part of the inspection surface of the inspection object, the defect on the entire inspection surface of the inspection object can be detected. In addition, as a method of moving the inspection surface and the light relatively, the optical system for shaping the light into a desired shape and obliquely irradiating the light may be provided with a mechanism for moving the light, or the inspection may be performed. The platform on which the object is placed may be moved. At this time, in order to reliably detect the defect, 10
Since it is not necessary to form an image on the detector at a high magnification of twice or more, a defect on the entire inspection surface of the inspection object can be detected in a short time. Further, at this time, if the light irradiating the inspection surface is linear, that is, if it is formed into an elongated slit shape, the unevenness defects in the longitudinal direction can be detected at one time.
It is possible to detect a defect on the entire inspection surface of the inspection object in a shorter time.

It is preferable that the light applied to the inspection surface is not totally reflected on the inspection surface at the portion where the light is incident. This is because, in the case of total reflection, the background noise increases, and it becomes difficult to detect the scattered light from the irregularity defect, that is, the S / N ratio may deteriorate. In general, since the surface layer of the LCD is made of a material that does not transmit ultraviolet light, when inspecting for irregularities on the surface of the LCD, the light to be irradiated is combined with light having a wavelength in the visible region or the infrared region. Then, the light can pass through the inside of the LCD without being reflected on the surface of the LCD. Therefore, there is no fear that the S / N ratio will be degraded, and it is possible to easily and reliably detect the surface irregularity defect. In addition, the light for inspecting the LCD includes laser light, light generated from a light emitting diode, light from a white light source, and light from a white light source as light having a wavelength in a visible region or an infrared region. Light monochromated by use can pass through the LCD.

Although the surface inspection method and apparatus are effective for detecting microscopic defects such as microscopic scratches and dust adhesion, in particular, there is a step in the internal structure such as an LCD through which light passes. However, the shadow due to the internal structure cannot be distinguished from the shadow due to the surface defect, and this is effective for detecting the surface irregularity defect of the apparatus in which it is difficult to detect only the surface irregularity defect.

As a detector for detecting scattered light,
Any of a line sensor in which charge-coupled devices (CCD) are arranged one-dimensionally, an imaging device in which these are two-dimensionally arranged, a photodiode, and a position sensor in which these are arranged may be used. Further, the luminance detected by the detector is displayed on a monitor, and the presence or absence and position of a defect on the inspection surface may be visually determined. However, the detected luminance is larger than a predetermined luminance when there is no irregularity defect. If a computer for judging whether or not the surface defect is detected is provided, the surface irregularity defect can be automated and accelerated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.
The same reference numerals are given and the detailed description is omitted.

In FIG. 1, a surface inspection apparatus 11 according to the present embodiment is disposed above an LCD 9 which is an inspection object for inspecting an irregularity defect on the surface 9a. This is the surface 9a of the LCD 9
And a light source 12 arranged in a line on an oblique optical axis L _{1 at} an angle θ = 45 degrees, and illuminating light emitted from the light source 12 is obliquely applied to a desired shape and the surface 9 a of the LCD 9. And an optical system 13. Further, the surface inspection apparatus 11 includes an observation system 14 disposed at an angle of 90 degrees with respect to the surface 9 a of the LCD 9, that is, on the optical axis L ₀ in a vertical plane, and image data of scattered light observed by the observation system 9. And an image processing system (not shown) for processing.

The light source 12 of this embodiment is a second harmonic generation device. This is achieved by irradiating an Nd: YAG laser or a Nd: YVO ₄ (neodymium-doped yttrium vanadate) laser, which is a solid-state laser, with light having a wavelength of 810 nm emitted from a known semiconductor laser as excitation light. By passing the 1064 nm fundamental wave generated by the laser through a nonlinear optical crystal element such as KTP (potassium titanate phosphate) in the resonator structure,
This is a second harmonic laser beam having a wavelength of 532 nm in the visible light region, and the second harmonic laser beam is emitted.

As shown in FIG. 1, the optical system 13 includes a known expander lens 21, a known collimator lens 22, a known concave cylindrical lens 23, and And a well-known spherical lens 24 which is a condensing lens. Therefore, the laser light emitted from the light source 12 is expanded via the expander lens 21 and the collimator lens 22
Is converted into a parallel light flux. After that, the cylindrical lens 2
In No. 3, only one direction of the parallel light is enlarged. Then, with the cylindrical lens 23 and the spherical lens 24, the size of light in one direction is enlarged, but the size of light in a direction perpendicular to the light is reduced, and the light is shaped into linear light R. The light is irradiated onto the surface 9a of the LCD 9. In the present embodiment, the light irradiated on the LCD 9 at an angle θ through the condenser lens 24 has an NA of about 0.02, a focal depth of 665 μm, a line width of about 30 μm,
The line length is about 9 mm.

On the other hand, the observation system 14 is, for example, a CCD image pickup device 26 of 380,000 pixels and having a size of 2/3 inch as a detector, and is disposed between the CCD image pickup device 26 and the LCD 9. Image of CCD imager 2
And an imaging lens 27 that forms an image on the imaging lens 6. The imaging lens of this embodiment has a magnification of 0.8 times and a working distance H of 30 to 50 mm. In this embodiment, C
The size of an image imaged at one time by the CD imaging device 26, that is, the imaging range is 8.25 mm × 11 mm.
It is about 1/4 of the entire surface of D9. Further, an image processing computer (not shown) is connected to the CCD imaging device 26, and a state in which it is determined in advance that there is no unevenness defect on the inspection surface is stored.

The surface inspection apparatus of this embodiment is configured as described above. Next, the operation of the present invention will be described. FIG. 2 is a schematic diagram for explaining the operation.

The laser light having a wavelength of 532 nm generated from the light source 12 is shaped into a linear light R by the optical system 13 and applied to the surface 9a of the LCD 9 at an angle of θ = 45 degrees. At this time, a portion p of the surface 9a where the light R is incident (shown by a thick solid line in FIGS. 3 and 4)
If there is no irregularity defect larger than the tolerance, an optical path indicated by M in FIG. 2 is taken. That is, the light R is reflected at the portion p.
The light passes through the inside of the LCD 9 and is reflected on the back surface 9b.
At this time, scattered light, that is, irregular reflection does not occur in the portion p. Therefore, as shown in FIG. 3A, the image captured by the CCD imaging device 26 is a region N (this is a horizontal synchronization signal (H sync)) where the reflected light reflected by the back surface 9b is captured.
Only some) in the center and position the position V _r from becomes bright region, the other region has a dark area (shown by hatching in the figure this). That is, areas scattered light to be generated K (which is shown by a two-dot chain line in FIG., In a position centered on the position V _S from H sync) it is also a dark area. B in FIG. 3 shows the luminance in the horizontal direction (the luminance distribution in the horizontal direction is the same everywhere when there is no irregularity defect in the portion p of the surface 9a where the light R is incident). The portion other than the N region is a dark region having a luminance equal to or less than a predetermined threshold value C.

In the portion p of the surface 9a where the light R is incident, an unevenness defect such as a flaw having an unacceptable size or adhesion of dust (for example, a flaw having a size of about 2 μm as shown in FIG. 2 in this embodiment) q If there is, scattered light is generated around the unevenness defect q, as indicated by a plurality of arrows S in FIG. That is, in this case, as shown in FIG. 4A, the image captured by the CCD imaging device 26 is a region where the scattered light of the size D centered on the portion q and the reflected light reflected on the back surface 9b are bright. The other areas are imaged as dark areas (which are indicated by hatching in the figure). In FIG. 4B, the solid line indicates the luminance in the horizontal direction (on the line indicated by X in FIG. 4A) including the unevenness defect q. On the line indicated by X, the portion of the region N of the reflected light reflected by the back surface 9b and the portion of the region K where scattered light is to be generated have a luminance larger than the predetermined threshold value C, and the other portions Has a luminance equal to or less than the threshold value C. In addition, in FIG. 4B, the dashed-dotted line indicates the luminance in the horizontal direction (for example, on the line indicated by Y in FIG. 4) including the portion without unevenness defects. Only the region N of the reflected light reflected at 9b has a luminance higher than a predetermined threshold value C (this is due to unevenness q
Is slightly larger than the luminance detected in the region N on the X-ray including the

In this embodiment, the CCD image pickup device 26 converts the image shown in FIG. 3 or 4 into a video signal and supplies it to an image processing system (not shown). here,
Among the images captured by the CCD imaging device 26, (from H sink position around the distance V _S) to detect the video signal in the vertical line area K, where the threshold C that is set in advance When a large luminance is detected, it is determined that the surface of the portion has an irregularity defect of an unacceptable size. That is, when a video signal of an image as shown in FIG. 3 is supplied, it is determined that the area K does not have an irregularity defect having an unacceptable size, and a video signal of an image as shown in FIG. When supplied, in the region K, it is determined that there is an unevenness defect q having a size larger than an allowable value on the X-ray.

The distances V _S and V _r between the area K and the area N
Is always constant, and the same LCD does not change its position even when the inspection surface moves relative to the light R. Therefore, for example, by moving a stage (not shown) on which the LCD 9 is mounted, the entire surface 9a of the LCD 9 is irradiated with illumination light, so that unevenness defects (scratch or adhered) having a size larger than the entire surface 9a are allowed. Garbage).

In this embodiment, linear light is irradiated from an oblique angle of 45 degrees. If the surface 9a of the LCD 9, which is the inspection surface, has unacceptably large irregularities such as scratches and dust, the irradiated light is irradiated. Is scattered on the surface 9a, and the scattered light is detected in a dark area having a luminance equal to or less than a predetermined value when there is no unevenness defect, thereby detecting the unevenness defect. did. Therefore, even if the unacceptable unevenness defect is as small as a micro unit, the scattered light is detected as a size D larger than the size d of the unevenness q, so that the unevenness defect can be easily detected. Yes and sure. In this embodiment, the inspection object is the LCD 9 and light in the visible light region is used.
In addition, since the light is irradiated at an angle of 45 degrees, the light is transmitted through the inside of the LCD 9 without being totally reflected by the surface 9a of the LCD 9, and an increase in background noise can be prevented. Can be detected. Further, since the irradiation light has a linear shape, defects on the entire inspection surface can be performed in a shorter time.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention.

For example, in the above embodiment, the light from the second harmonic generation element having a wavelength in the visible light range is used as the light source 12, but a semiconductor laser, a solid-state laser, or a gas laser may be used. As described above, light other than laser, monochromatic light, or a light emitting diode (LED) may be used.

In the above embodiment, the expander lens 21 and the collimator lens 2 are used to shape the irradiation light source into linear light on the surface 9a of the LCD 9 to be inspected.
2. Although the cylindrical lens 23 and the spherical lens 24 are used, the lens for shaping into a predetermined shape (for example, a linear shape) is not limited to this, and the number of lenses to be used is also limited to this. No need at all. For example, in the optical system 13, in order to form linear light R,
Although the concave cylindrical lens 23 and the spherical lens 24 are used, instead of the spherical lens 24, a convex cylindrical lens is used, and the curved surface is disposed so as to form 90 degrees with respect to the curved surface of the concave cylindrical lens. You may make it. In the above embodiment, the light source 12 and the optical system 13 has been arranged on the optical axis L ₁ of theta = 45 degrees with respect to the surface 9a of which is inspected LCD 9, the test piece surface (inspection surface) As long as the optical system 13 has a structure capable of irradiating light obliquely, there is no problem even if it is not arranged in this way. In addition, the angle θ of the light applied to the surface of the inspection object (inspection surface) is a dark area having a luminance equal to or less than a predetermined value when there is no unevenness on the surface. Has a brightness greater than a predetermined value,
What is necessary is just to arrange | position at the angle which can detect the scattered light clearly.

Further, in the above-described embodiment, the CCD image pickup device 26 arranged two-dimensionally is used as the light receiving sensor. However, this may be a CCD line sensor or other solid-state image pickup device (for example, a bucket relay device ( BBD) or the like, or a photodiode. Further, the structure of the observation system 14 need not be limited to the above-described embodiment. For example, imaging lenses having different working distances and magnifications may be used, or a plurality of lenses may be used.
That is, if the magnification is small, the area of the inspection surface of the inspection object imaged by the detector at one time becomes large and the inspection time becomes short, but the size D of the scattered light received by the detector becomes small. If the magnification is large, the size D of the scattered light received by the detector becomes large and the detection becomes easy, but the inspection time becomes long, so that the specification of the unevenness defect of the inspection object can be satisfied. Magnification.

In the above embodiment, the inspection object is LC
Although the description has been made with reference to D, it is of course possible to detect unevenness defects on the surface of another device, which is an unevenness defect in which the attachment of scratches and dust in micro units is unacceptable. In particular, since light passes through the interior having a stepped structure, the conventional method cannot determine whether it is a shadow due to this internal structure or a shadow due to a surface irregularity defect, that is, easily detect only the surface irregularity defect This is effective for surface inspection of equipment that cannot be performed. Examples of such an apparatus include the LCs described in the above examples.
In addition to D, for example, a monochrome CCD device before forming an on-chip color filter may be used.

[0032]

As described above, according to the surface inspection method and apparatus of the present invention, surface irregularities that are extremely small in micro units but larger than an allowable level can be easily and reliably detected. be able to. In addition, since observation at a low magnification becomes possible, if the light irradiated on the surface is relatively moved with respect to the inspection surface, the inspection time of the unevenness defect on the entire inspection surface can be shortened.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a surface inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining an operation of the surface inspection apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing an image in the case where an inspection surface has no irregularities larger than an allowable size and a change in luminance in a horizontal direction of the image in the embodiment of the present invention. B shows the magnitude of the luminance in the horizontal direction in the image of A.

FIG. 4 is a diagram showing an image in the case where an inspection surface has an irregularity defect having an unacceptable size on the inspection surface and a change in luminance in the horizontal direction of the image in the embodiment of the present invention. B shows the magnitude of the luminance in the horizontal direction including the unevenness defect in the image of A.

FIG. 5 is a front sectional view showing a surface inspection apparatus in a conventional example.

FIG. 6 is a diagram illustrating an example of an image captured by a detector of a surface inspection device in a conventional example.

[Explanation of symbols]

9 ... LCD, 9a ... surface, 11 ... surface inspection device,
12 light source, 13 optical system, 14 observation system, 26
…… CCD imager, d …… Size (of unevenness defect), D
… Size (of scattered light), K… area, L ₁ , L ₀ …
Optical axis, p: part where light on the inspection surface is incident, q: concave / convex defect (on the inspection surface), R: light (linear), θ: angle.

Claims (16)

[Claims] 1. A method according to claim 1, wherein a part of the inspection surface is irradiated with light obliquely to the inspection surface, and a portion of the inspection surface where the light is incident has an irregular defect of an unacceptable size. When the light is scattered, and in the case where there is no irregularity defect in the portion, in a region that is detected as a dark region having a low brightness below a predetermined level,
A surface inspection method, wherein a defect on the inspection surface is detected by detecting the scattered light. 2. The surface according to claim 1, wherein the position of the defect is detected by moving the light applied to the inspection surface relatively to the inspection surface. Inspection methods. 3. The surface inspection according to claim 1, wherein the inspection surface irradiated with the light is moved relatively to the light to detect a position of the defect. Method. 4. The surface inspection method according to claim 2, wherein the light applied to the inspection surface has a linear shape. 5. The surface inspection method according to claim 1, wherein the light is irradiated at an angle such that the light is not totally reflected at the portion. 6. The surface inspection method according to claim 5, wherein the inspection surface is a surface of a liquid crystal display. 7. The surface inspection method according to claim 6, wherein the light has a wavelength in a visible region or an infrared region. 8. A light source that generates illumination light, and the illumination light is shaped into light having a desired shape, and the light is incident on a part of the surface of the inspection object in an oblique direction with respect to the surface. An optical system, if there is no irregularity defect of an unacceptable size in a part of the surface where the light is incident, the luminance of the part is arranged at a position where the luminance is detected as a dark area having a low luminance of a predetermined level or less. A surface inspection apparatus provided with a detector for detecting scattered light generated when the portion has the irregularity defect. 9. The surface inspection apparatus according to claim 8, further comprising a mechanism that moves the light relative to the inspection object and irradiates the entire inspection object. 10. The surface inspection apparatus according to claim 9, wherein the desired shape is a linear shape. 11. The position where the observation system is provided,
The position of the surface on which the light is incident is in a vertical plane.
Surface inspection apparatus according to 1. 12. The surface inspection apparatus according to claim 11, wherein the inspection object has a structure in which the light is transmitted from the surface to the inside. 13. The surface inspection apparatus according to claim 12, wherein the inspection object is a liquid crystal display, and the light has a wavelength in a visible region or an infrared region. 14. The surface inspection apparatus according to claim 13, wherein the detector is a charge-coupled device or a photodiode. 15. The method according to claim 15, wherein the light is any one of laser light, light generated from a light emitting diode, light from a white light source, and light obtained by converting the light from the white light source into a single color using an optical element. The surface inspection apparatus according to claim 14, wherein: 16. The computer according to claim 15, further comprising a computer that determines whether or not the detected luminance is higher than the predetermined luminance and detects the irregularity defect.
Surface inspection method described in 1.