JP3899874B2 - Evaluation method and apparatus for liquid crystal panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal panel evaluation method and an evaluation apparatus, and more particularly to a manufacturing technique suitable for examining the thickness of a liquid crystal layer provided in a transflective or transmissive liquid crystal panel.
[0002]
[Prior art]
In general, a liquid crystal panel is formed by bonding two substrates and injecting liquid crystal between both substrates. Electrode patterns for applying a voltage to the liquid crystal layer are respectively formed on these two substrates. When a liquid crystal display device is configured using this liquid crystal panel, the thickness of the liquid crystal layer (cell gap) greatly affects the display characteristics. Therefore, the thickness of the liquid crystal layer is set with high accuracy and the liquid crystal layer is disposed on the entire panel. It is very important to form a uniform thickness throughout.
[0003]
For this reason, in the manufacturing process of the conventional liquid crystal display device, after the liquid crystal panel is constructed, an inspection for evaluating the thickness and uniformity of the liquid crystal layer is performed. In addition, when a foreign substance is mixed in the liquid crystal layer, a display defect is caused. Therefore, an inspection may be performed as to whether or not there is a foreign substance inside the liquid crystal layer.
[0004]
Here, the above inspection may be performed simply to know whether the manufactured liquid crystal panel is good or defective and to eliminate defective products. Also, the thickness of the liquid crystal layer of the manufactured liquid crystal panel and other characteristic values. It may be used to obtain the management data for fine-tuning the manufacturing conditions of the production line by obtaining results and specifying the degree of quality of the liquid crystal panel and classifying it, or feeding back the results For example, it is widely used as an action for evaluating liquid crystal panels.
[0005]
In the manufacturing process of a conventional liquid crystal display device, when inspecting a liquid crystal panel having a liquid crystal layer, annular illumination is performed by an annular light source, and light emitted from the light source is converted into linearly polarized light by a polarizing plate. The method of irradiating the liquid crystal panel with this linearly polarized light, passing the transmitted light through a polarizing plate, and finally analyzing the transmitted light with a colorimeter (other CCD camera, photomultiplier, or spectrometer) is adopted. May be.
[0006]
In addition, light emitted from a light source that can be regarded as a point light source is applied to a liquid crystal panel through a polarizing plate, and the transmitted light is detected by a colorimeter installed obliquely through the polarizing plate. There is also a method.
[0007]
In the above method, the direction of the polarization transmission axis of the polarizing plate on the light incident side with respect to the optical axis and the direction of the polarization transmission axis of the polarizing plate on the light detection side are appropriately related, for example, 20 to 60. Since the hue of the detection light changes according to the thickness of the liquid crystal layer by installing it so as to have an angle difference of degrees, the thickness of the liquid crystal layer is based on the hue of the image taken by the colorimeter. I check for abnormalities and the presence of foreign objects.
[0008]
[Problems to be solved by the invention]
However, in the conventional method for inspecting a liquid crystal panel, the cell thickness is calculated based on the change in hue, but an accurate value can be obtained by the presence of a film such as a color filter provided on the liquid crystal panel. There is a problem that can not be.
[0009]
Therefore, the present invention solves the above-described problems, and an object of the present invention is to provide a novel liquid crystal panel evaluation method and evaluation apparatus that can acquire information on a liquid crystal layer with higher accuracy than before.
[0010]
[Means for Solving the Problems]
The liquid crystal panel evaluation method of the present invention includes a first substrate, a second substrate disposed opposite to the first substrate, a color filter formed on the first substrate side of the second substrate, A liquid crystal panel evaluation method for obtaining a thickness of the liquid crystal layer in a liquid crystal panel having a liquid crystal layer disposed between a first substrate and the second substrate, wherein the liquid crystal panel is linearly polarized with respect to the liquid crystal panel The thickness of the liquid crystal layer is obtained based on the wavelength at which the minimum value in the visible light region is obtained in the spectral spectrum of the detection light obtained from the transmitted light that has passed through the color filter and the liquid crystal layer.
[0011]
According to such a configuration of the present invention, the characteristics of the liquid crystal layer, for example, the thickness of the liquid crystal layer, the retardation Δn of the liquid crystal layer, based on the spectral characteristics of the detection light, for example, the wavelength or frequency position of the extreme value of the spectral spectrum. Panel evaluation can be performed by obtaining confirmation of the presence or absence of foreign matter in the liquid crystal layer. In other words, the extreme wavelength position and frequency position of the spectral spectrum of the detection light are hardly affected by the hue of the detection light, so the hue other than the thickness of the liquid crystal layer, such as a color liquid crystal panel having a color filter, is affected. It is possible to measure the thickness of the liquid crystal layer without hindrance even for a liquid crystal panel having a structure that provides the above.
[0012]
In the liquid crystal panel evaluation method, when the linearly polarized light is incident on the liquid crystal panel, the linearly polarized light is incident at an incident angle larger than 0 ° and smaller than a critical angle with respect to the surface of the liquid crystal panel. Also good. Then, the optical path length in the liquid crystal layer of incident light can be increased, and the detection sensitivity of the thickness of the liquid crystal layer can be increased.
[0018]
Another liquid crystal panel evaluation method of the present invention is the above-described liquid crystal panel evaluation method, wherein the thickness of the liquid crystal layer is obtained at a plurality of locations of the liquid crystal panel, and the liquid crystal panel is based on the change of the thickness depending on the location. Check for foreign material in the layer. In this way, foreign matters in the liquid crystal layer (including foreign matters attached on the inner surface of the substrate of the liquid crystal panel) can be examined.
[0019]
The liquid crystal panel evaluation apparatus according to the present invention includes a first substrate, a second substrate disposed opposite to the first substrate, a color filter formed on the first substrate side of the second substrate, An apparatus for evaluating a liquid crystal panel for obtaining a thickness of the liquid crystal layer in a liquid crystal panel having a liquid crystal layer disposed between a first substrate and the second substrate, wherein linearly polarized light is applied to the liquid crystal panel. In an optical system for irradiation, an analyzer for obtaining detection light from transmitted light that has passed through the color filter and the liquid crystal layer, a photodetector for detecting the detection light, and a spectrum of the detection light, And an evaluation processing unit that obtains the thickness of the liquid crystal layer based on the wavelength at which the minimum value in the visible light region is obtained.
[0020]
According to such a configuration of the present invention, the characteristics of the liquid crystal layer, for example, the thickness of the liquid crystal layer, the retardation Δn of the liquid crystal layer, based on the spectral characteristics of the detection light, for example, the wavelength or frequency position of the extreme value of the spectral spectrum. Panel evaluation can be performed by obtaining confirmation of the presence or absence of foreign matter in the liquid crystal layer. In other words, the extreme wavelength position and frequency position of the spectral spectrum of the detection light are hardly affected by the hue of the detection light, so the hue other than the thickness of the liquid crystal layer, such as a color liquid crystal panel having a color filter, is affected. It is possible to measure the thickness of the liquid crystal layer without hindrance even for a liquid crystal panel having a structure that provides the above.
[0021]
In the liquid crystal panel evaluation apparatus, the optical system may irradiate the liquid crystal panel with the linearly polarized light at an incident angle larger than 0 ° and smaller than a critical angle with respect to the surface of the liquid crystal panel. Then, the optical path length in the liquid crystal layer of incident light can be increased, and the detection sensitivity of the thickness of the liquid crystal layer can be increased.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of a liquid crystal panel evaluation method and evaluation apparatus according to the present invention will be described in detail with reference to the accompanying drawings. The liquid crystal panel evaluation method and evaluation apparatus of the present invention are used for evaluation of a transmissive or transflective liquid crystal panel.
[0029]
(First embodiment)
FIG. 1 is a schematic configuration diagram schematically showing a configuration of a first embodiment of an evaluation apparatus used in a liquid crystal panel evaluation method according to the present invention.
[0030]
The evaluation apparatus 20 of the present embodiment has a light source 22 composed of a halogen lamp, LED (light emitting diode), CFL (cold cathode tube), etc., and a light guide composed of an optical fiber or the like above a base 21 on which the liquid crystal panel 10 is placed. Incident optical system having an optical device 23, a condenser 24 including a condenser lens provided at the tip of the light guide path 23, and a polarizing plate 25 used as a polarizer disposed at the tip of the condenser 24. Is provided.
[0031]
Further, below the base 21, a concentrator 27 including a polarizing plate 26 used as an analyzer and a condensing lens disposed at the tip of the polarizing plate 26 so as to face the incident optical system. A detection optical system including a light guide 28 made of an optical fiber or the like connected to the light collector 27, a spectrometer connected to the light guide 28, and a light detector 29 made of a spectroscopic unit. .
[0032]
Detection data obtained by the photodetector 29 is sent to the evaluation processing unit 30. The evaluation processing unit 30 preferably has an operation processing function for the detection data, and is particularly configured to perform operation processing based on an operation program such as an MPU (microprocessor unit). It is desirable to be.
[0033]
The base 21 is configured to be movable by a drive mechanism 31 in a direction perpendicular to the drawing sheet, for example. On the other hand, at least a part of the incident optical system and the detection optical system (for example, the condenser 24, the polarizing plate 25, the polarizing plate 26, and the condenser 27) is configured to be movable in the horizontal direction in the figure by the drive mechanism 32, for example. Has been. Therefore, the drive mechanisms 31 and 32 allow the incident optical system and the detection optical system and the liquid crystal panel 10 placed on the base 21 to freely move relative to each other on a virtual plane parallel to the panel surface of the liquid crystal panel 10. Can be moved. Various drive mechanisms that are functionally equivalent to the drive mechanisms 31 and 32 can be configured by appropriately moving at least one of the incident optical system, the detection optical system, and the base 21. it can. The base 21 has a frame shape with a through hole 21a, and the inner edge portion of the base 21 supports the outer edge of the liquid crystal panel.
[0034]
FIG. 2 schematically shows an optical path when the liquid crystal panel 10 is evaluated by the evaluation device 20 of the present embodiment. Here, a case where the liquid crystal panel 10 is a monochrome transflective liquid crystal panel will be described. The liquid crystal panel 10 includes a first substrate 10b, a second substrate 10c, a sealing material 10d for bonding these substrates, and a liquid crystal layer 10a sandwiched between spaces formed by the substrates 10b and 10c and the sealing agent 10d. Have. A counter transparent electrode 10e as a first electrode is provided on the first substrate 10b, a reflective layer 11a such as Al on the second substrate 10c, and ITO provided for each pixel on the reflective layer 11a. A transparent electrode 11b as a second electrode made of is provided. Further, the reflection layer 11a is provided with an opening 11c for each pixel. A liquid crystal device incorporating such a liquid crystal panel functions as a transflective liquid crystal device. That is, when there is sufficient external light, the external light is reflected on the reflective layer 11a, and functions as a reflective type that displays using this reflected light. On the other hand, when the external light is insufficient, the light emitted from the backlight incorporated so as to be positioned on the second substrate 10c side when the liquid crystal device is formed is reflected on the second substrate 10c and the reflective layer 11a. By passing through the opening 11c and passing through the transparent electrode 11b, the liquid crystal layer 10a, the counter transparent electrode 10e, and the first substrate 10b, it functions as a transmission type in which display is performed.
[0035]
In the above incident optical system, the polarizing plate 25 has a polarization transmission axis 25t parallel to a predetermined direction (for example, a plane P intersecting with a plane orthogonal to the optical axis and a plane including the optical axes of incident light and outgoing light). In addition, it has a polarization absorption axis 25a parallel to a plane orthogonal to the optical axis and a direction orthogonal to the predetermined direction (for example, the direction P and the direction S orthogonal to the optical axis). By passing through the polarizing plate 25, linearly polarized light Li having a vibration surface including the direction of the polarization transmission axis 25t is formed and is incident on the liquid crystal panel 10 at an incident angle θi.
[0036]
On the other hand, the above-described detection optical system is set so as to detect the transmitted light of the linearly polarized light Li incident at the incident angle θi, and is emitted from the liquid crystal panel 10 at the emission angle θo substantially equal to the incident angle θi. The transmitted light enters the polarizing plate 26 and is finally guided to the photodetector 29. The polarization plate 26 has a polarization absorption axis 26a parallel to the polarization transmission axis 25t of the polarization plate 25 with reference to the optical path, and a polarization transmission axis orthogonal to the polarization transmission axis 25t of the polarization plate 25 with reference to the optical path. 26t.
[0037]
When the linearly polarized light Li is incident from the first substrate 10b side of the liquid crystal panel 10, the first substrate 10b, the counter transparent electrode 10e, the liquid crystal layer 10a, the transparent electrode 11b, the opening 11c of the reflective layer 11a, and the second substrate 10c. Passes and becomes the output polarized light Lt.
[0038]
In the detection optical system, the outgoing polarized light Lt enters the polarizing plate 26. At this time, the outgoing polarized light Lt passes through the liquid crystal layer 10a, whereby the predetermined retardation of the liquid crystal layer 10a (the optical anisotropy Δn of the liquid crystal molecules in the liquid crystal layer 10a and the thickness d of the liquid crystal layer 10a) Product), the polarization state of the linearly polarized light Li changes, and is different from the original linearly polarized light Li (for example, elliptically polarized light). Therefore, a polarized light component different from the polarization transmission axis 26t of the polarizing plate 26 in the outgoing polarized light Lt is absorbed by the polarizing plate 26 having the polarization absorption axis 26a. On the other hand, the polarization component that vibrates in the direction of the polarization transmission axis 26t of the polarizing plate 26 in the outgoing polarized light Lt passes through the polarizing plate 26 and is detected by the photodetector 29 as detection light Lo.
[0039]
The detection light Lo has a light intensity corresponding to the retardation Δn · d of the liquid crystal layer 10a or a hue or dispersion spectrum corresponding to the color dispersion characteristic of the retardation Δn · d. Therefore, since there is a correlation between the light intensity, hue or dispersion spectrum of the detection light Lo and the retardation of the liquid crystal layer 10a, this correlation is theoretically determined or determined by experiment or simulation. Based on the light intensity, hue, or dispersion spectrum of the detection light Lo, the retardation Δn · d of the liquid crystal layer 10a or the thickness d of the liquid crystal layer 10a can be obtained if Δn of the liquid crystal is known. .
[0040]
In the present embodiment, the thickness d of the liquid crystal layer is set by utilizing the fact that the extreme value (minimum value or maximum value) of the dispersion spectrum of the detection light changes in frequency according to the amount of change in the polarization state of the detection light. Details are described later.
[0041]
Here, the incident angle θi = the outgoing angle θo may be an appropriate angle of 0 ° or more and less than 90 °, but when the critical angle (total reflection angle) θth with respect to the surface of the substrate 10b in the linearly polarized light Li is exceeded, Since the linearly polarized light Li is totally reflected on the surface of the substrate 10b and light does not enter the liquid crystal layer 10a, in practice, θi = θo is performed in an angle range where the angle is 0 degree or more and less than θth. Even within this angle range, increasing the angle as much as possible can increase the optical path length in the liquid crystal layer 10a and, as a result, increase the detection sensitivity to the liquid crystal layer 10a. As the length increases, the light intensity of the detection light Lo itself decreases.
[0042]
In this embodiment, a spectroscopic unit is used as the photodetector 29, and spectral characteristic data of transmitted light is obtained. The spectroscopic unit can obtain a spectroscopic spectrum at least in the visible light region of the detection light Lo or detection data corresponding to the spectroscopic unit. For example, a spectroscope using a spectroscopic element or a multiplex spectroscopic method is used. Any of a spectroscopic device, a multichannel spectrometer, etc. may be sufficient.
[0043]
In the spectroscopic unit, the spectral spectrum itself in the visible light region of the light reaching along the optical path, or various optical spectra equivalent to the spectroscopic spectrum, that is, capable of deriving the spectroscopic spectrum by a predetermined mathematical operation. A parameter (such as a complex dielectric constant) is detected.
[0044]
An example of the spectrum of the detection light Lo is shown in FIG. In this spectrum, there are a minimum value Mb and a maximum value Mp in the visible light region. The wavelength λb from which the minimum value Mb is obtained and the wavelength λp from which the maximum value Mp is obtained have a predetermined correlation with the thickness d of the liquid crystal layer 10a of the liquid crystal display panel 10.
[0045]
In general, the optical characteristics of the liquid crystal, that is, the optical anisotropy Δn, the twist angle θ, the thickness d of the liquid crystal layer 10a, the optical axis between the transmission polarization axis of the polarizing plate 25 and the transmission polarization axis of the polarizing plate 26. Based on the angle φ (90 degrees in this embodiment), the emission spectrum of the light source, and the optical characteristics of the first substrate and the second substrate, the Jones vector method or the 4 × 4 matrix method is used. A spectrum can be derived. The positions of the minimum value Mb and the maximum value Mp in the spectrum, that is, the wavelengths λb and λp can be represented by the parameters. Therefore, if the optical conditions of the light source, the incident side optical system, and the emission side optical system are constant, the thickness d of the liquid crystal layer 10a when the predetermined Δn, θ, φ is set to the wavelength λb or λp. It can be expressed by a function F (λ). The function d = F (λ) indicating the thickness can be practically expressed by a first-order to fourth-order function of the wavelength λb or λp.
[0046]
FIG. 4 shows two spectral spectra when the thickness d of the liquid crystal layer 10a is changed (d = d0, d = d0−Δd). Normally, the wavelengths λb and λp in the visible light region monotonously increase according to the function F (λ) as the thickness d of the liquid crystal layer 10a increases. The function F (λ) may be an empirical formula obtained from data obtained by repeating experiments in advance.
[0047]
FIG. 5 shows a case where a monochrome panel A not provided with a color filter as shown in FIG. 2 and color panels B and C provided with a color filter as shown in FIG. These show the above-mentioned spectral spectra. Here, the color panel B and the color panel C have color filters provided with colored layers having different hues. In this case, in order to reduce variation in measurement, the range of light split by the spectroscopic unit is set to a range that passes through an area including a plurality of pixels in the liquid crystal display area.
[0048]
As shown in FIG. 5, although the spectral spectrum changes greatly depending on the presence or absence of a color filter, the type of color filter, etc., the positions of the minimum value Mb and the maximum value Mp hardly change, and the wavelengths λb and λp are substantially constant. It is. Therefore, when the thickness d of the liquid crystal layer is obtained using the function F (λ), the detection value is hardly affected by the presence or absence of the color filter or the change in filter color tone.
[0049]
FIG. 6 shows a schematic flowchart of an operation program for operating the evaluation processing unit 30 described above. First, when the liquid crystal display panel 10 is set in the evaluation device and predetermined data is input from an input device (not shown) such as a keyboard by an operator or the like, the input data is stored in the memory in the evaluation processing unit 30. Save to. This input data includes cell conditions, that is, the optical anisotropy Δn and twist angle θ of the liquid crystal, the angle φ of the transmission polarization axis of the polarizing plates 25 and 26, the thickness, material, or optical characteristics of the panel substrate. The evaluation processing unit also receives and records the target value d0 of the thickness d of the liquid crystal layer 10a.
[0050]
Based on the input cell condition and target value, the evaluation processing unit 30 calculates the function F (λ). This function F (λ) indicates the relationship between the thickness d of the liquid crystal layer 10a and the wavelength λb or λp. In the present embodiment, the wavelength λb corresponding to the minimum value Mb of the spectral spectrum is used.
[0051]
Next, it waits for a start command input from the outside. When the start command is input, the measurement position is set at an appropriate location, and spectroscopic measurement is started. Then, spectral data is sent from the spectroscopic unit to the evaluation processing unit 30, and the evaluation processing unit obtains the wavelength λb based on the spectroscopic data.
[0052]
Then, the thickness d of the liquid crystal layer 10a is calculated from the wavelength λb using the function F (λ), and the difference Δd = | d−d0 | () between the calculated thickness d and the target value d0. The absolute value of the difference between d and d0) is output to the outside (for example, display means, recording means, etc.).
[0053]
Thereafter, when the measurement location is changed according to a predetermined measurement pattern, for example, when measurement is performed at a plurality of locations on the liquid crystal panel 10, the relative positional relationship between the liquid crystal panel 10 and the optical system is changed by the drive mechanism. And repeat measurement at another location in the same manner as described above.
[0054]
(Second Embodiment)
Next, a second embodiment according to the present invention will be described with reference to FIG. Here, the liquid crystal panel 10 to be evaluated is the same as that shown in FIG. Moreover, since the structures of the photodetector 29 and the evaluation processing unit 30 are the same, the description thereof is omitted.
[0055]
In the evaluation apparatus 40 of this embodiment, a light source 41, a polarizing plate 42 that converts light emitted from the light source 41 into linearly polarized light, and linearly polarized light emitted from the polarizing plate 42 pass through the liquid crystal panel 10. A polarizing plate 44 that receives the transmitted light, a photodetector 45 that detects light transmitted through the polarizing plate 44, and an evaluation processing unit 46 that processes detection data obtained by the photodetector 45 are provided. Also in the present embodiment, a spectroscopic unit is used as the light detector 45 as in the light detector 29 of the first embodiment.
[0056]
In this embodiment, the polarization transmission axis 42t of the polarizing plate 42 is set in a direction orthogonal to the drawing sheet, and the polarization absorption axis 44a of the polarizing plate 44 is also set in a direction orthogonal to the drawing sheet.
[0057]
In this embodiment, light emitted from the light source 41 passes through the polarizing plate 42 and linearly polarized light Li having a vibration plane parallel to the polarization transmission axis 42 t is incident on the liquid crystal panel 10. The incident light Li passes through the liquid crystal panel 10 and then enters the polarizing plate 44, where a polarized component having a vibration plane parallel to the polarization absorption axis 44a of the polarizing plate 44 is absorbed, and the remaining component is detected light Lo. Is detected by the photodetector 45.
[0058]
This embodiment shows a case where both the incident angle θi and the outgoing angle θo of light with respect to the liquid crystal panel 10 are 0 degrees. Here, the transmitted light Lt passes through the liquid crystal layer 10a, and its polarization state changes with respect to the linearly polarized light of the incident light Li according to the retardation of the liquid crystal layer 10a, so that the polarization component having a vibration plane parallel to the paper surface of the figure. The polarization component passes through the polarizing plate 44 and is detected by the photodetector 45.
[0059]
In the embodiment described above, the liquid crystal panel for the monochrome type-semi-transmissive semi-reflective liquid crystal device has been described as an example. However, as shown in FIG. 7, the panel for the color semi-transmissive semi-reflective liquid crystal device. In addition, the evaluation apparatus and the evaluation method of the present invention can be used.
[0060]
As shown in FIG. 7, a liquid crystal panel 100 for a color transflective liquid crystal device has a first substrate 101 and a second substrate 102 bonded together with a sealing material 103, and a liquid crystal layer 104 is disposed between the substrates. is there. On the inner surface of the first substrate 101, a counter transparent electrode 111 is formed as a first electrode made of a transparent conductor such as ITO. On the surface of the counter transparent electrode 111, SiO ₂ A hard protective film 112 made of or the like is formed. Further, an alignment film 113 is formed on the surface of the hard protective film 112, and the surface of the alignment film 113 is rubbed.
[0061]
On the other hand, a reflective layer 114 made of a metal film such as Al is formed on the inner surface of the substrate 102, and an insulating layer 115 is formed on the reflective layer 114. A transparent electrode 116 as a second electrode is formed on the insulating layer 114. The reflective layer 114 is provided with an opening (not shown) for each pixel. A colored layer 117 is formed on the transparent electrode 116, and the colored layer 117 is covered with a protective film 118 for flattening the surface. The colored layer 117 is configured so that different colors (for example, red, green, and blue) are arranged in an appropriate pattern. An alignment film 119 is formed on the protective film 118, and its surface is rubbed.
[0062]
In the color transflective liquid crystal panel 100 configured as described above, since the color filter including the colored layer 117 is formed, the light passing through the liquid crystal layer 104 passes through the color filter. A predetermined color tone will be exhibited.
[0063]
Since the colored layer 117 has different hues between adjacent pixels, and there are variations in hue and low reproducibility thereof, it is possible to use a method for obtaining the thickness of the liquid crystal layer using the hue of the detection light Lo. difficult. However, as in the above-described embodiment, by obtaining the thickness of the liquid crystal layer 104 using the spectral characteristics of the detection light, a more accurate value can be obtained than before.
[0064]
In the above description, the liquid crystal panel for the transflective liquid crystal device has been described as an example. However, the evaluation device and the evaluation method in the above embodiment may be applied to the liquid crystal panel for the transmissive liquid crystal device. it can.
[0065]
In the embodiment described above, it is possible to detect the thickness of the liquid crystal layer of the liquid crystal panel with high accuracy and almost without being affected by the presence or absence of a color filter or variations in hue.
[0066]
In the above embodiment, the wavelength λb of the spectral spectrum is used to obtain the thickness of the liquid crystal layer. However, λp may be used, and the frequency corresponding to the wavelength and various values associated therewith. The corresponding value may be used.
[0067]
In the above embodiment, a method for obtaining the thickness of the liquid crystal layer as the characteristics of the liquid crystal layer is described in detail. However, the liquid crystal layer retardation Δn · d is not limited to the thickness of the liquid crystal layer. Can also be used in the same manner, for example, when determining the presence or absence of foreign matter in the liquid crystal layer. For example, for the presence or absence of foreign matter in the liquid crystal layer, the above function F (λ) is calculated at a plurality of locations, and the fact that the function F (λ) changes more than the target value do when there is foreign matter is used. A method for confirming the presence of a foreign substance by the above method can be used.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram schematically showing a structure of a first embodiment of an evaluation apparatus according to the present invention.
FIG. 2 is an enlarged explanatory view schematically showing a measurement principle of the first embodiment.
FIG. 3 is a schematic configuration diagram schematically showing the structure of a second embodiment of the evaluation apparatus according to the present invention.
FIG. 4 is a graph showing a spectral spectrum detected by the evaluation apparatus of the present invention.
FIG. 5 is a graph showing an example of a spectral spectrum detected by the evaluation apparatus of the present invention for liquid crystal panels with different color filters and other conditions.
FIG. 6 is a schematic flowchart showing an outline of an operation program of the evaluation apparatus according to the present invention.
FIG. 7 is a schematic cross-sectional view schematically showing the structure of a color transflective liquid crystal panel.
[Explanation of symbols]
10 ... LCD panel
10a, 104 ... Liquid crystal layer
10b, 101 ... first substrate
10c, 102 ... second substrate
11a, 114 ... reflective layer
11b, 116 ... Transparent electrode
11c ... opening
10e, 111 ... opposite transparent electrode
20, 40 ... evaluation device
21 ... Base
22, 41 ... Light source
23. Light guide (incident side)
24 ... Condenser (incident side)
25, 42 ... Polarizing plate (incident side)
26, 44 ... Polarizing plate (outgoing side)
27 ... Condenser (outgoing side)
28: Light guide (outgoing side)
29, 45 ... Photodetector (spectral unit)
30, 46 ... Evaluation processing unit (MPU)
100: Color transflective liquid crystal panel

Claims (5)

A first substrate; a second substrate disposed opposite to the first substrate; a color filter formed on the first substrate side of the second substrate; and between the first substrate and the second substrate A liquid crystal layer disposed on the liquid crystal panel, and a liquid crystal panel evaluation method for determining the thickness of the liquid crystal layer in a liquid crystal panel comprising:
In the spectral spectrum of the detection light obtained from the transmitted light that has passed through the color filter and the liquid crystal layer, linearly polarized light is incident on the liquid crystal panel, based on the wavelength at which the minimum value in the visible light region is obtained. A method for evaluating a liquid crystal panel, comprising: obtaining a thickness of a liquid crystal layer. A method for evaluating a liquid crystal panel according to claim 1,
When the linearly polarized light is incident on the liquid crystal panel, the linearly polarized light is incident at an incident angle larger than 0 ° and smaller than a critical angle with respect to the surface of the liquid crystal panel. .   3. The method for evaluating a liquid crystal panel according to claim 1, wherein the thickness of the liquid crystal layer is obtained at a plurality of locations of the liquid crystal panel, and foreign matter in the liquid crystal layer is removed based on a change due to the location of the thickness. A method for evaluating a liquid crystal panel, characterized by investigating. A first substrate; a second substrate disposed opposite to the first substrate; a color filter formed on the first substrate side of the second substrate; and between the first substrate and the second substrate A liquid crystal panel, and a liquid crystal panel evaluation apparatus for determining the thickness of the liquid crystal layer in a liquid crystal panel having
An optical system for irradiating the liquid crystal panel with linearly polarized light; an analyzer for obtaining detection light from transmitted light that has passed through the color filter and the liquid crystal layer; and a photodetector for detecting the detection light; An evaluation apparatus for a liquid crystal panel, comprising: an evaluation processing unit that obtains a thickness of the liquid crystal layer based on a wavelength at which a minimum value in a visible light region is obtained in a spectral spectrum of the detection light. An evaluation apparatus for a liquid crystal panel according to claim 4,
The apparatus for evaluating a liquid crystal panel, wherein the optical system irradiates the liquid crystal panel with the linearly polarized light at an incident angle larger than 0 ° and smaller than a critical angle with respect to a surface of the liquid crystal panel.

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