TWI731658B - Image determination device for metal wire grid polarizer - Google Patents

Abstract

An image determination device for metal wire grid polarizer includes a carrier, a polarizer test specimen, a backlight source, a hollow motor, and an image capture device. The carrier has a light transmitting portion, and the light transmitting portion penetrates the carrier. The polarizer test specimen is placed on the light transmitting portion. The backlight source emits light toward the light transmitting portion. The hollow motor is disposed on a side where the polarizer test specimen is placed on the carrier. The image interception device is disposed on the other side of the hollow motor facing the polarizer test specimen and includes a telecentric lens and a photosensitive coupling element. The telecentric lens receives light passing through the light transmitting portion, the polarizer test specimen and the hollow motor, and the photosensitive coupling element capture the light to convert it into a specimen image.

Description

Image type judging device for metal wire grid polarizer

The present disclosure relates to an image-based determination device for metal wire grid polarizers, and more specifically, to an image-based determination device for metal wire grid polarizers that can automatically determine the extinction ratio of the polarizer.

The wire grid polarizer (WGP) is mainly composed of nano-level metal wire grids with high extinction coefficient. When a light wave passes through the nano-level metal wire grid, because the structure is smaller than the wavelength, only 0 is left. Order diffraction. At this time, the periodic parameters and geometric shape of the grating will exhibit specific birefringence characteristics for the light wave, so that the incident electric field vibration component (defined as Pλ) perpendicular to the structure passes through without being affected by the grating, but the electric field parallel to the structure The vibrational component (Sλ) is caused by the extinction principle explained by the Ewald-Osceen extinction theory to produce destructive interference in the light traveling direction, and the light retroreflecting direction does not persist without the interference of the resonance excitation electric field of the induced current, so the S polarization state passes through Nano-grade metal wire grids exhibit strong reflection characteristics. The lightest state and darkest state measured by the P polarization state and S polarization state can define the extinction ratio to determine whether the product meets the specifications.

The current method of detecting the extinction ratio of the polarizer is to use a color luminance meter with a rotatable mechanism, and use the software's global search algorithm to search for the best dark state value and the corresponding value of the polarizer. The value of the bright state is used to obtain the extinction ratio. However, this measurement method cannot effectively obtain the extinction ratio of a large area, so that defects in the product may not be detected, resulting in unstable quality and even mottles (Mura).

In summary, the inventor of the present invention has designed an image determination device for metal wire grid polarizers to improve the lack of existing technology and further enhance its industrial application.

In view of the above problems, the object of the present invention is to provide a metal wire grid polarizer image determination device that can determine the extinction ratio of a polarizer with a large area, so as to solve the problem that the conventional technology can only determine the extinction ratio of a polarizer with a small area. .

According to the object of the present invention, there is provided an image determination device for a metal wire grid polarizer, which includes a stage, a polarizer test piece, a backlight, a hollow motor, and an image capturing device. The carrier has a light-transmitting part, and the light-transmitting part penetrates the carrier. The polarizer test piece is placed on the light-transmitting part. The backlight emits light toward the light-transmitting part. The hollow motor is arranged on the side where the polarizer test piece is placed on the carrier. The image capturing device is arranged on the other side of the hollow motor facing the polarizer test piece, and includes a telecentric lens and a photosensitive coupling element. The telecentric lens receives light passing through the light transmitting part, the polarizer test piece and the hollow motor, and the photosensitive coupling element captures Take the light to convert it into a test piece image.

Preferably, the test piece image can correspond to a preset area in the polarizer test piece, and the test piece image includes a plurality of pixels, and the image determination device uses the exposure time of the photosensitive coupling element and each of the plurality of pixels The luminance value of produces the extinction ratio corresponding to a plurality of pixels.

Preferably, the size of the preset area may be 6cm x 6cm.

Preferably, the image determination device can generate uniformity by extinction ratios in a plurality of pixels, where uniformity = (maximum extinction ratio-minimum extinction ratio)/(maximum extinction ratio + minimum extinction ratio), When the uniformity is greater than the preset value, it is determined that the extinction ratio of the preset area is inconsistent.

Preferably, the preset value may be 10%.

Preferably, the polarizer test piece may include a plurality of determination areas, the image capturing device and the backlight move at the same time to correspond to the plurality of determination areas, and the test piece images obtained through the plurality of areas are spliced into an overall image.

Preferably, the hollow motor may further include an analyzer, which includes a plurality of polarizers, and the analyzer can be rotated to change the polarization state of the light passing through the hollow motor.

In summary, the image determination device of the metal wire grid polarizer of the present invention has one or more of the following advantages:

(1) By correspondingly converting the exposure time in the test piece image into a luminance value, the extinction ratio of a large area can be measured, so as to improve the shortcomings of the conventional technology that only a small area can be measured.

(2) By defining the uniformity, the present invention can effectively determine whether there are defects on the surface of the polarizer test piece, reduce the situation that defective products are still processed afterwards and increase the cost, and effectively improve the quality stability of the product.

1, 2: Image-based judging device

110, 210: Backlight

120, 220: carrier

121, 221: light transmitting part

130, 230: Polarizer test piece

140, 240: hollow motor

150, 250: Image capture device

151, 251: photosensitive coupling element

152, 252: Telecentric lens

260: Lower bracket

270: Slide

280: Upper bracket

290: upper cover

D: Ring

In order to make the technical features, content and advantages of this creation and the effects it can achieve more obvious, the creation is combined with the accompanying drawings and described in detail in the form of embodiments as follows: Figure 1 is an embodiment according to the invention The block diagram of the image determination device for the metal wire grid polarizer; Figure 2 is a schematic diagram of the image determination device for the metal wire grid polarizer according to an embodiment of the present invention; Figure 3 is a graph of the exposure time and brightness value of the image determination device for the metal wire grid polarizer according to the embodiment of the present invention; Figure 4 is the image determination device for the metal wire grid polarizer according to the embodiment of the present invention The calibration curve diagram; Figure 5 is a schematic diagram of the test piece image of the metal wire grid polarizer image determination device according to an embodiment of the present invention.

In order to understand the technical features, content and advantages of the present invention and its achievable effects, the present invention is described in detail with the accompanying drawings and in the form of embodiment expressions as follows, and the figures used therein are only For the purpose of illustration and auxiliary description, it is not necessarily the true scale and precise configuration after the implementation of the present invention. Therefore, the scale and configuration relationship of the attached drawings should not be interpreted, and the scope of rights of the present invention in actual implementation should not be interpreted. Narrate.

In the drawings, for the sake of clarity, the thickness or width of the panel, light guide, etc. are enlarged. Throughout the specification, the same reference numerals denote the same elements. It should be understood that when an element is referred to as being "on" or "connected to" or "disposed on" another element, it can be directly on or connected to the other element, or the intermediate element can also be exist. Conversely, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements. As used herein, “connection” or “setting” can refer to a physical and/or electrical connection or setting. In addition, if the terms "first", "second", and "third" are used for descriptive purposes only, they cannot be understood as indicating or implying relative importance or their order relationship.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have meanings commonly understood by ordinary knowledge in the technical field to which the present invention belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings in the context of related technologies and the present invention, and will not be interpreted as idealized or excessive The formal meaning, unless explicitly defined as such in this article.

FIG. 1 is a block diagram of an image determination device for a metal wire grid polarizer according to an embodiment of the present invention.

As shown in the figure, the image determination device 1 of a metal wire grid polarizer includes a stage 120, a polarizer test piece 130, a backlight 110, a hollow motor 140, and an image capturing device 150. The backlight source 110 is used to emit a light, more specifically, a plurality of light-emitting diodes are arranged in the backlight source 110 to emit light. For example, the plurality of light-emitting diodes may be indium gallium nitride (InGaN) semiconductors with energy gaps between 3.4 eV and 3.1 eV to emit light of a specific wavelength of purple or blue. Alternatively, the backlight 110 is further provided with phosphor to absorb the blue light emitted by the light-emitting diode and convert it into light of other colors (for example, red light or green light), so as to combine with the blue light to form white light. However, the present invention is not limited to this, and the light emitted by the backlight source 110 may also adopt other colors according to the actual application conditions of the metal wire grid polarizer. In addition, in other embodiments, the light-emitting diode in the backlight 110 may be replaced by an organic light-emitting diode, or a tungsten wire or the like may be used as a light source.

The stage 120 has a light-transmitting portion 121 that penetrates the entire stage 120, and at least a part of the polarizer test piece 130 is placed on the light-transmitting portion 121 so that the light emitted by the backlight 110 can pass through the light-transmitting portion 121 It is irradiated on the polarizer test piece 130 to be tested. Therefore, the light-transmitting portion 121 is composed of a material with high light transmittance. For example, the light-transmitting portion 121 may be composed of silicon dioxide (SiO2), or composed of polymethyl methacrylate (PMMA) organic polymer. In other words, the transparent part 121 itself can be composed of inorganic matter or organic matter, and it is mainly used to carry the polarizer test piece 130. In this case, the area of the light-transmitting portion 121 itself may be larger than the area of the entire polarizer test piece 130, so that the entire polarizer test piece 130 can be irradiated by light when placed on the light-transmitting portion 121. However, the light-transmitting portion 121 is not necessarily a physical element. In some embodiments, the light-transmitting portion 121 may also be a perforation to allow light to pass through the perforation. In this case, the perforation may have an aperture slightly smaller than that of the polarizer test piece 130, so that the central area of the polarizer test piece 130 is aligned with the perforation, and the corners of the polarizer test piece 130 are placed on the stage 120 adjacent to the perforation. So that the central area can still illuminate the light passing through the perforation.

The polarizer test piece 130 is composed of a nano-grade metal wire grid with a high extinction coefficient. In this embodiment, the material of the metal wire grid is aluminum (Al), but it is not limited thereto. When the product has no defects, the extinction ratio of each position of the polarizer test piece 130 is a fixed value, but when a defect occurs in the product, the extinction ratio of the position where the defect occurs will be different from other positions. Therefore, the image judging device 1 of the metal wire grid polarizer of the present invention can determine whether there are obvious defects on the surface of the polarizer test piece 130 by defining a uniformity, so as to improve the quality stability of the product. This is described in more detail in the text.

The hollow motor 140 is connected to the image capturing device 150 to drive the image capturing device 150 to rotate. More specifically, the hollow motor 140 drives the image capturing device 150 to rotate on a plane parallel to the polarizer test piece 130, so that the image capturing device 150 can The light passing through the polarizer test piece 130 is obtained from different angles. For example, the hollow motor 140 can use a servo motor with a high-precision encoder to coordinate with a small angle of rotation and precise positioning. However, the present invention is not limited to this. The hollow motor 140 can also use a stepping motor with high mechanical precision to reduce possible shaking during rotation and improve the sharpness of image capture.

The image capturing device 150 includes a telecentric lens 152 and a photosensitive coupling element 151. The telecentric lens 152 is used to receive the light passing through the light-transmitting part 121, the polarizer test strip 130 and the hollow motor 140, and the photosensitive coupling element 151 captures the light to convert the test strip image. Furthermore, the image of the test piece obtained by the photosensitive coupling element 151 corresponds to a preset area of approximately 6cm x 6cm in the polarizer test piece 130. Therefore, the telecentric lens 152 with a constant zero angle of view can effectively Reduce the distortion of the picture in the test piece image that may be caused by parallax (or it may not produce distortion at all).

The above-mentioned test piece image contains a plurality of pixels, each of the plurality of pixels has a brightness value, and the brightness value is correspondingly converted by the exposure time of the photosensitive coupling element 151 in the process of capturing light. , To obtain the extinction ratio of each of the plurality of pixels. Furthermore, since the image of the test piece corresponds to the preset area in the polarizer test piece 130, that is, the extinction ratio of each pixel is the extinction ratio of each corresponding position in the polarizer test piece 130. Therefore, in the test piece image, the uniformity can be further defined to determine the surface condition of the polarizer test piece 130. The uniformity formula is as described in formula (1): uniformity = (maximum extinction ratio-minimum extinction ratio)/(maximum extinction ratio + minimum extinction ratio) (1)

The uniformity will change due to the maximum value and the minimum value of the extinction ratio. That is, when the surface of the polarizer test piece 130 has unevenness or other defects, the uniformity will be affected. For example, when the surface of the polarizer test piece 130 is dirty or uneven, the maximum or minimum extinction ratio will change accordingly, and the uniformity value will change accordingly. If the uniformity exceeds 10%, then The image determination device 1 can automatically determine that the polarizer test piece 130 is defective. However, the present invention is not limited to this, and it may be determined that the polarizer test piece 130 is defective when the uniformity exceeds 5%.

With the image determination device 1 of the metal wire grid polarizer of this embodiment, the extinction ratio of each position in the large area of the polarizer test piece 130 can be obtained, and the uniformity can be further defined to determine the polarizer test piece 130 Surface condition, timely elimination of defective products, reduce the cost of defective products still being processed, and effectively improve product quality stability.

FIG. 2 is a schematic diagram of an image determination device for a metal wire grid polarizer according to an embodiment of the present invention. In this embodiment, the accompanying drawings will be used to specifically illustrate the connection relationship and relative positions of the various components in the device.

As shown in the figure, the image determination device 2 of the metal wire grid polarizer includes a stage 220, a polarizer test piece 230, a backlight 210, a hollow motor 240, an image capturing device 250, a lower bracket 260, an upper bracket 280, and上盖290。 Upper cover 290. The lower bracket 260 is used to carry the entire image determination device 2, and therefore can be an optical shockproof platform that is anti-vibration or shaking. The height of the upper bracket 280 can be adjusted to match the focal length of the image capturing device 250. The upper cover 290 can be used to prevent the components of the image capturing device 250 from being exposed to the air, so as to reduce external interference.

The carrier 220 is disposed on the lower bracket 260, and the carrier 220 has a light-transmitting portion 221, and the light-transmitting portion 221 is a large-area high-transmittance glass to carry the polarizer test piece 230. In this embodiment, the polarizer test strip 230 includes a plurality of determination areas, and the size of each of the plurality of determination areas may be equal to the preset area size as described above. The backlight source 210 is disposed between the light-transmitting part 221 and the lower bracket 260. The hollow motor 240 is arranged on the sliding rail 270 and drives the image capturing device 250 to rotate horizontally. Furthermore, the hollow motor 240 and the backlight source 210 can correspondingly move laterally along the horizontal plane to obtain the test piece image of each of the plurality of determination areas. For example, when the size of the polarizer test piece 230 is 12 x 12cm, the image determination device 2 of the metal wire grid polarizer sets the size of each of the plurality of determination areas to 6cm x 6cm, that is, the entire polarizer The test piece 230 is divided into a total of four judgment areas, and the four judgment areas are Obtain the extinction ratio for a certain area In addition, the image-based determination device 2 can combine the test strip images obtained in a plurality of determination areas, and stitch the separately obtained test strip images into an overall image. In this case, it can also be used with the above-mentioned embodiment. For the obtained uniformity, the extinction ratio in the overall image of the polarizer test piece 230 is incorporated into formula 1, and it is further judged whether the entire polarizer test piece 230 has obvious defects.

The image capturing device 250 is disposed above the hollow motor 240 to receive the light passing through the light transmitting portion 221, the polarizer test piece 230 and the hollow motor 240. More specifically, the hollow motor 240 includes an analyzer 241, which includes a plurality of polarizers, and the analyzer 241 rotates to change the polarization state of the light passing through the hollow motor 240. The power density of the light passing through the polarizer test piece 230 is changed by the analyzer 241 to determine whether the required polarized light is obtained. The plurality of polarizers may be composed of metal wire grid polarizers, however, the present invention is not limited to this, and the polarizers may also be composite organic films. For example, the main structure of the polarizer can be a polyvinyl alcohol (PVA) film, and includes triacetate cellulose (TAC), pressure-sensitive adhesive (PSA film), release film and protective film. ).

With the image determination device 2 of the metal wire grid polarizer of this embodiment, the images of the test strips respectively obtained through the plurality of determination areas can be spliced into the overall image to more effectively determine the extinction ratio of the entire polarizer test strip 230. Further matching the application of uniformity can also effectively improve the quality stability of the product.

Figure 3 is a graph of the exposure time and brightness value of the image determination device for the metal wire grid polarizer according to the embodiment of the present invention; Figure 4 is the image determination device for the metal wire grid polarizer according to the embodiment of the present invention The calibration curve diagram; Figure 5 is a schematic diagram of the test piece image of the metal wire grid polarizer image determination device according to an embodiment of the present invention. In this embodiment, the same components are represented by the same component symbols, which can refer to the description of the above embodiments, and the same technical features will not be repeated.

The image determination device 2 of the metal wire grid polarizer of the present invention includes a stage 220, a polarizer test piece 230, a backlight 210, a hollow motor 240, and an image capturing device 250. The image capturing device 250 receives the light emitted by the backlight 210 and passing through the stage 220, the polarizer test piece 230, and the hollow motor 240, and then converts the light into a test piece image, and corresponds the exposure time to the brightness value to obtain the extinction ratio. More specifically, the image determination device 2 can use the data measured by a spectrometer as the basis for conversion between the exposure time and the brightness value. For example, use a spectrometer to use a polarizer test piece 230 with a specific specification as a standard test piece, and use a rotating mechanism to measure the corresponding brightness value and exposure time for each angle of the polarizer test piece 230. The test results are as follows Table 1 shows.

As shown in Table 1, the exposure time and brightness value are recorded separately for each angle of the standard test piece. then. The test results in Table 1 are plotted as a graph of exposure time and brightness value. As shown in Figure 3, the curve in the figure is a graph of the change in exposure time and brightness value between an angle of 1 degree, and it can be observed The exposure time and the brightness value are symmetrical. As shown in Figure 4, the brightness value corresponding to the reciprocal of the exposure time can be drawn as a calibration curve graph, that is, the exposure time and the brightness value can be converted correspondingly to each other. In this embodiment, the calibration curve formula measured by the standard test piece is y=2020.4x-13.921, and the linearity is 99.97%. The calibration curve obtained by the above standard test piece can be used for the polarizer test of the same specification The numerical conversion of the slice 230, that is, the image determination device 2 can use the calibration curve to convert the exposure time into a luminance value, and then obtain the extinction ratio of each pixel according to the luminance value.

In this embodiment, the image determination device 2 automatically brings the calibration line into the main program as a conversion standard to convert the exposure time into a brightness value, and further obtain the extinction ratio based on the brightness value. In actual use, the luminance value obtained by the conversion of the calibration curve is compared with the luminance value obtained by using the color luminance meter. The error of the extinction ratio calculated by the two is within 10%, and in this embodiment only It is 3.33%, as shown in Table 2, (24455-23641)/24455=3.33%.

In addition, in this embodiment, in addition to displaying the extinction ratio of each pixel, the test piece image can also directly display the location of the defect. For example, on the polarizer test piece 230 to be tested, two circles D are drawn as marks with a strange pen, so that the extinction ratio of the marked position is changed to simulate the defect. When the image determination device 2 uses the calibration curve to convert the exposure time into a brightness value, and converts the brightness value into an extinction ratio value to generate a test piece image (as shown in FIG. 5). In the test piece image, different colors represent different extinction ratios. More specifically, the higher the extinction ratio, the closer the color displayed in the test piece image is to blue (cold color), and vice versa, the closer it is to red (warm color). Therefore, the two circles D in the test piece image correspond to the marked positions on the polarizer test piece 230, and the extinction ratio of the marked positions is 24,000 (dark blue), and the circle D corresponding to the mark has about 23,000 The (green) extinction ratio can be used to find the location of the defect clearly from the image of the test piece.

In this embodiment, by making the exposure time and the corresponding brightness value into a calibration curve, the image determination device of the metal wire grid polarizer can use the calibration curve as the conversion standard to obtain the deviation The extinction ratio of any point on the light test piece. In addition, you can also observe whether the polarizer test piece is defective through the image of the test piece.

In summary, the image determination device of the metal wire grid polarizer of the present invention can effectively determine whether there are defects on the surface of the polarizer test piece by using the image pattern of the test piece, so as to improve the quality stability of the product.

The above descriptions are merely illustrative and not restrictive. Any equivalent modifications or alterations that do not depart from the spirit and scope of the present invention should be included in the scope of the appended patent application.

1: Image-based judging device

110: Backlight

120: Stage

121: Translucent part

130: Polarizer test piece

140: Hollow motor

150: Image capture device

151: photosensitive coupling element

152: Telecentric lens

Claims (6)

An image judging device for a metal wire grid polarizer, comprising: a stage with a light-transmitting portion through which the light-transmitting portion penetrates the stage; a polarizer test piece placed on the light-transmitting portion; and a backlight Source, which emits a light toward the light-transmitting part; a hollow motor arranged on the side where the polarizer test piece is placed on the stage; and an image capturing device arranged on the other side of the hollow motor facing the polarizer test piece One side includes a telecentric lens and a photosensitive coupling element. The telecentric lens receives the light passing through the light transmitting portion, the polarizer test piece and the hollow motor, and the photosensitive coupling element captures the light to convert it into a Test piece image; wherein the test piece image corresponds to a predetermined area in the polarizer test piece, and the test piece image includes a plurality of pixels, the imaging type determination device uses an exposure time of the photosensitive coupling element and A luminance value of each of the plurality of pixels produces an extinction ratio corresponding to the plurality of pixels. The imaging determination device according to claim 1, wherein the predetermined area size is 6cm x 6cm. The image determination device according to claim 1, further generating a uniformity by the extinction ratio in the plurality of pixels, where the uniformity = (maximum extinction ratio-minimum extinction ratio)/(maximum extinction ratio) Ratio+minimum extinction ratio), when the uniformity is greater than a preset value, it is determined that the extinction ratio of the preset area is inconsistent. The image determination device according to claim 3, wherein the default value is 10%. The imaging determination device according to claim 1, wherein the polarizer test strip includes a plurality of In the judging area, the image capturing device and the backlight move at the same time to correspond to a plurality of judging areas, and the test piece images respectively obtained through the plurality of judging areas are spliced into an overall image. The image determination device according to claim 1, wherein the hollow motor includes an analyzer, the analyzer includes a plurality of polarizers, and the analyzer rotates to change the polarization state of the light passing through the hollow motor.

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