JP2003172667A - Apparatus for measuring photoconductor luminance pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring a photoconductor luminance pattern capable of easily obtaining such data on the luminance distribution of a photoconductor as to easily enable the design of a precise gradation pattern which requires a large number of items of data. <P>SOLUTION: The apparatus for measuring the photoconductor luminance pattern is provided with a light source, a plurality of luminance detecting means each for detecting the luminance of the photoconductor which occurs when the photoconductor is arranged adjacently to the light source and light incident from the light source and transmitting through the photoconductor is radiated from the photoconductor, and a black box means for surrounding the light source, the photoconductor, and detecting surfaces of the luminance detecting means to isolate them from outside light. The locational relationship between the plurality of luminance detecting means is known. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide luminance pattern measuring apparatus. 2. Description of the Related Art Generally, a screen of a liquid crystal display device has a light source disposed on the back side or side surface of the screen, and light from the light source passes through a liquid crystal cell or the like and is viewed by a viewer. It is configured to reach the eyes. At this time, the light source may be a linear light source or one or a plurality of point light sources. In the former case, when light is guided from the light source toward the front side from the back surface or the side surface of the screen, a difference in brightness or the like occurs between the near side and the far side of the screen from the light source.
In the latter case, since the point light sources are used in combination, an area where light from the point light source overlaps a lot and an area where the light overlaps a little are generated. It is bright in a large area and conversely dark in a small area. Due to such circumstances, the screen of the liquid crystal display device has uneven brightness even if only the combination of the light source and the liquid crystal cell is used. In order to eliminate such unevenness in brightness, a rectangular plate-like light guide layer called a light guide plate is often provided mainly on the back surface or side surface of the liquid crystal cell. Such a light guide,
Light from a light source is incident on the back surface or side surface of the liquid crystal cell and travels through the light guide so that the light is emitted from the surface of the liquid crystal cell.In a region where the amount of light in the light guide is large, the light is emitted from the surface. In order to suppress the amount of light, a structure devised so as to maintain the amount of light in an area where the amount of light is small is employed. [0005] The light guide may not only propagate the light but also, for example, may be configured to change the traveling direction of the light by 60 °. From such a point, it can be said that the light guide is a light conversion device in the sense that it has a function of changing the amount of incident light and the traveling direction. FIGS. 4 (a) and 4 (b) are conceptual diagrams for explaining a light guide, in which a square thick plate-like light guide 200 and a light guide 200 are arranged adjacent to side surfaces. The plurality of LEDs 12 (12a, 12b ...) provided are shown by a plan view (a) and a side view (b) shown on the right side thereof. Arrow A in the side view (b) indicates emission of light from the light guide 200. In FIG. 4A, a substantially circular curve C above the LED 12 conceptually shows a range of a region where the brightness of the surface of the light guide is increased by the incidence of light from the LED 12. Further, one LED 12 (12
Since a) and the adjacent LED 12 (12b) irradiate light, the shaded area Cw where the substantially circular C overlaps indicates that the area is higher in luminance. In FIG. 4A, reference numeral 201 denotes
It is conceptually shown that the light guide 200 is a layered portion indicated by a gradation pattern 210 disposed in a surface region on the light emission side. The light guide 200 is configured such that the light transmittance can be adjusted for each part in order to suppress the amount of light, and a layered portion 201 of a gradation pattern is formed on the surface side of the light guide 200 as illustrated. That is, the gradation pattern 210 is
Normally, the layer thickness and the diameter of the partial region 220 are changed so as to form the layered portion 201 including the circular or rectangular dot-shaped partial region 220 shown in black in FIG. It is formed by creating a light guide. The size of the dot is selected so that the light transmission amount differs in each partial region 220 and the brightness of the light guide surface is adjusted. In this way,
The dots of various sizes are set by forming them on a part of the light guide as layered portions 201 of a pattern with a specific arrangement. FIGS. 4A and 4B show an LED.
When light is incident on the light guide 200 from No. 12, the circular dot side is a region having lower luminance than the region where the circle C is described. Then, FIG.
Describes a large number of dots with a large diameter on the low-luminance side. The pattern of the circular dots illustrated in FIG. 4A is designed so that a large amount of light is emitted from the layered portion 201 in a low-luminance region. This is an example in which a partial area of a circular dot is formed. Next, a method of designing a gradation pattern will be described. In order to design the gradation pattern as described above, first, with the light source arranged adjacent to the back surface of the light guide, a densitometer or the like is sequentially arranged at both ends of the light guide surface near and far from the light source. Then, the luminance is measured by the densitometer. Next, based on the values obtained by the measurement, the luminance of the central portion between the two ends is calculated, and this value and the previous luminance value are used as one set to form a luminance distribution. Then, the size of the dots can be adjusted so as to obtain a gradation pattern corresponding to the luminance distribution. By the way, it is known that in the luminance distribution on a surface such as a screen of a liquid crystal display device, there is a phenomenon that light and dark appear as a boundary line due to a visual effect peculiar to human eyes. This visual effect will be described with reference to FIGS. FIGS. 5A and 5B show the light guide 20.
FIG. 5A is a plan view (a), and FIG. 5B is a side view schematically showing the magnitude of luminance data. Reference numeral 60 denotes a light source, and reference numeral 90 denotes a reflector. This side view (b) shows the magnitude of the value of the luminance data on the side of the light guide 200 (in the direction in which the value is viewed from the reflector 90 side).
From the position shown in the plan view of the light guide 200, for example, means that the luminance data is shown to be smaller (larger) in order from the luminance of the light guide surface position, for example. ing. The above-mentioned visual effect is, as shown in FIG. 5B, a gradient distribution from left to right as viewed from the side of the light guide 200 as a luminance distribution as a cross-sectional profile ('
→ '→' or →→)
Even if the luminance distribution is a continuous gradient as shown in the figure, the human eye will see a light and dark boundary line at a certain value in the middle of the gradient distribution. That there is a visual effect. For this reason, in general, an intermediate value of the luminance at both ends (for example, position) is adopted for the luminance distribution of the central portion (for example, position). Is selected so as not to substantially cause the influence of, and to have uniform brightness over the entire screen. This value is selected based on experience, and is refined through several trial productions and evaluations to finally determine a gradation pattern. In this sense, the design of the gradation pattern usually requires trial and error. The actual state of the creation of such a gradation pattern will be described based on actual measurement example data. In FIG. 5B, the luminance value of the light guide surface actually measured with reference to the light guide surface for determining the gradation pattern and the luminance of each position are corrected so that the luminance of the light guide surface becomes uniform. The correction values '〜' calculated as described above are shown from the side. As shown in FIGS. 5A and 5B,
In the state where the luminance measurement points were set on the surface of the light guide as indicated by the positions 〜, the luminance was measured for each luminance measurement point by a luminance measuring device. Table 1 shows the results. FIG.
According to the schematic diagram shown from the side of, for example, at a luminance measurement point to, the luminance value is 3 units in cd / m ² in order.
496, 2342, 2112. [Table 1] In order to make the luminance uniform on the surface of the light guide 200, for example, as shown in FIGS. In inverse proportion, it is preferable to provide a gradation pattern by designing the dot diameter so that the correction values as indicated by 'to' are obtained. For this reason, the actual measurement can be performed on a point-by-point basis, and the position of the point can be calculated and calculated so as to be an intermediate value between the measured value of the point and the measured value of the point. However, in order to obtain a point based on a point and a point based on the point, similarly, it is only necessary to perform a relatively simple calculation, for example, based on the point and the point. It is not easy to calculate a correction value for a position such as a point. As described above, the design of the light guide and the design of the gradation pattern involve the step of determining the gradation pattern by trial and error by taking the above-described visual effects into account. In this step, Using the intermediate values as described above, the luminance value is set so as to be smoothly connected to the values at both ends of light and dark. However, since all of these steps are manually performed by trial and error, the labor and time required for the manual calculation are a remarkably large load on the designer, and calculation errors are apt to occur. Therefore, to avoid such calculation errors,
Since the number of "intermediate value setting locations" must be at most one or two, the number of "intermediate value setting locations" is increased, that is, a precision that requires a large number of data is required. There is a problem that a suitable gradation pattern cannot be easily obtained. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to easily design a precise gradation pattern that requires a large number of data. It is an object of the present invention to provide a light guide luminance pattern measuring device capable of easily obtaining such light guide luminance distribution data. Means for Solving the Problems In order to solve the above problems,
The present invention relates to a light source, and the light guide, which is generated when light incident from the light source and propagating through the light guide is emitted from the light guide when the light guide is disposed adjacent to the light source. A plurality of brightness detection means for detecting the brightness of each of the light source,
The light guide, and dark box means surrounding the detection surface of the brightness detection means and isolated from external light, wherein the plurality of brightness detection means have a known positional relationship to each other. Provided is a light guide luminance pattern measuring apparatus. According to this invention, the dark box means cuts off the light by isolating the light source, the light guide, and the detection surface of the luminance detecting means from light from outside the dark box means. Therefore, each of the luminance detecting means detects the luminance of each region of the light guide surface corresponding to the position of each of the luminance detecting means without being affected by the external light. Then, since the positional relationship between the luminance detecting means is known to each other, each luminance detecting means can obtain the luminance data as a set of luminance data arrays according to the positional relation, and the luminance data array is 3 shows a luminance pattern on a light guide surface. Accordingly, since the brightness data array indicates the brightness pattern of the light guide surface, the light guide is arranged adjacent to the light source, and the light pattern of the light guide is obtained simply by making light incident on the light guide. Can be easily obtained. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an outline of a light guide luminance pattern measuring apparatus, FIG. 2 is a block diagram showing an outline when an image scanner is used as a luminance detecting means, and FIG. 3 is a light guide gradation pattern. It is a flowchart which shows a measuring method. Note that the light guide luminance pattern measuring device is hereinafter simply referred to as a measuring device. In FIG. 1, reference numeral 10 denotes a light source, and 20 denotes a plurality of luminance detecting means (five luminance detecting means 21, 2 in the illustrated example).
2, 23, 24, 25) and 30 are arithmetic means, 50 is a dark box as dark box means, and 100 is a design device.
Reference numeral 200 denotes the light source 1 in the dark box 50 in the design apparatus 100.
2 shows a light guide that can be arranged between 0 and the luminance detection means 20. The present measuring device comprises a light source 10 and a luminance detecting means 2.
0 and a dark box 50. The light source 10 is arranged adjacent to the back surface of the light guide 200, and is configured to allow the light L1 to enter the light guide 200. When the light L1 is incident, the light guide 20
0 means the surface is bright. A plurality of luminance detecting means 20
The light guide 200 is installed adjacent to the light source 10 and the light L1
Is detected, the brightness of the brightened surface of the light guide 200 is detected, and a set of brightness data is output. Each of the plurality of luminance detecting means 20 is provided as having a known positional relationship with each other. The dark box 50 is configured to surround the light source 10, the light guide 200 to be measured, and at least the detection surface 20 </ b> S of the luminance detection unit 20, isolate the light from outside, and block the light. It is to be noted that an arithmetic means 30 can be connected to the plurality of luminance detecting means 20 to constitute a design apparatus.
In this case, the luminance detecting means 20 can send each luminance data DXY to the calculating means 30. Further, the calculating means 30 can include a computer program which is programmed in advance so as to calculate and obtain a gradation pattern based on each of the brightness data DXY obtained by the plurality of brightness detecting means 20. When each luminance data DXY is sent from the luminance detecting means 20, a gradation pattern is calculated and obtained. Next, each component will be described in more detail. The light source 10 is configured using an LED, a white cold-cathode tube, or the like so that light can be incident from the back surface of the light guide 200. The number of the plurality of luminance detecting means 20 is, for example, five in FIG. 1, but may be any number of two or more. For example, the plurality of luminance detecting means 20 are arranged in an array or a matrix as if the mutual positional relationship is known. ing. When the light from the light guide 200 reaches the luminance detecting means 21 to 25 shown in FIG.
It refers to the surface from 1 to 25 where the luminance is detected. The fact that the positional relationship between each other is known means that the distance and direction from one luminance detecting means (for example, 21) to another luminance detecting means (for example, 22 to 25) are known in a plane or space. It means something. Therefore, the positional relationship between the plurality of luminance detecting units 20 can be indicated by using coordinate values on a coordinate system with a certain point as the origin. One luminance detecting means (for example, 21) detects the luminance of the surface of the light guide 200. At this time, light (for example, light emitted from a certain point P ₀ on the surface of the light guide 200) for L2), to detect the brightest luminance closest position of the luminance detecting means from the point P _0, the luminance detection means farther detects the brightness of a small amount of light. Conversely, each luminance detecting means detects the luminance in a state where the light quantity from the point on the surface of the light guide closest to the luminance detecting means is largest and the light quantity from the point at the far position is small. Therefore, if the positional relationship between the luminance detecting means 20 is known and each luminance detecting means 20 detects the luminance of each part of the surface of the light guide 200, each luminance detected by each luminance detecting means 20 From the set of data DXY, the light guide 20
Since the brightness of each point on the 0 surface can be obtained, the brightness of the intermediate point between the points can be further calculated from the positional relationship, for example, by interpolation, and the brightness distribution is set as a more detailed data set. The brightness of the surface of the light guide 200 can be grasped as a distribution. As such a luminance detecting means 20, for example, a so-called image scanner (not shown) can be used. The image scanner includes light detection means (not shown) arranged in a matrix, detects the luminance of the light guide 200 as a distribution on a matrix plane, and outputs luminance data at each matrix position to a pixel. The data can be sent to the arithmetic means 30 as digital data in units. In the case of an image scanner, it is convenient to detect the brightness of a light guide having a size such as a monitor screen of a portable notebook personal computer. For example, a digital camera can be used as the luminance detecting means 20 for the design of a light guide used for an internally illuminated signboard or the like already installed on the exterior of a building or the like. In this case, by photographing with a digital camera, the luminance detecting means detects the luminance of the large light guide when using these large light guides as a distribution on the matrix plane, and divides the luminance data at each matrix position. The digital data can be sent to the arithmetic means 30 as digital data in pixel units. In using these luminance detecting means 20, as shown in FIG. 2, an image scanner 120 as a luminance detecting means can be installed at a position adjacent to the surface of the light guide 200. Scanner 12
0 and a diffuser 130 for adjusting the exposure.
Can be interposed. This diffuser 130
Thus, the exposure state is adjusted so that the gradation at the brightest position of the light guide 200 is accurately converted into data, and the light guide 200 is adjusted.
Can be detected. In addition, in FIG.
0 is not shown and is behind the light guide 200 (the back side of the paper).
Located in. The dark box 50 is, as shown in FIG.
0, the light guide 200, and at least the detection surface of the luminance detection means 20 are configured to be isolated from external light and to block external light. As the dark box means, a case like a box-shaped dark box used as a photographic device may be used. However, the light source 10, the light guide 200, and the detection surface of the luminance detection means 20 are surrounded by external light. It is not necessarily required to be box-shaped as long as a closed space for light guide luminance detection is formed in isolation from light and light from the outside of the present design device can be blocked. Therefore, the light source and the luminance detecting means may be set in a dark room, and the light guide may be arranged at a predetermined position therebetween. In this case, if the luminance detecting means has an image pickup surface having a size of, for example, about 30 cm square like the image scanner 120, the light source 10, the light guide 200, and the luminance detecting means 20 and the light source 10, the light guide 200, and the luminance detecting means 20
The dark box 50 can be configured so as to surround the detection surface 20 </ b> S of FIG. On the other hand, if the light source 10 and the luminance detecting means 20 are, for example, both small, the dark box 50 may be configured to surround all of them and house them so as to be isolated from external light. Good. For example, the light source 10 and the light guide 200 are arranged such that the right side portion (centering on the position of the luminance detecting means 20) of the dark box 50 in FIG.
In addition, a luminance detecting means 20 may be accommodated. The arithmetic means 30 uses a large number of luminance data to increase the number of repetitions of the calculation to secure a desired calculation accuracy and to obtain a gradation pattern which can correspond to the luminance distribution of the light guide. The program can be composed. That is, similarly to the conventional method, the brightness of the position may be calculated from the light guide surface position as shown in FIG. 5, and at the same time, an intermediate value between the two is calculated. For this purpose, not only a well-known linear interpolation method but also a method of applying various functional curves can be used. As described above, calculating the luminance data as a planar distribution by a program ensures the reproducibility of creating a gradation pattern, and sets a program for denser distribution data with a desired accuracy. be able to. Therefore, it is possible to eliminate the ambiguity of conventionally setting an intermediate value by trial and error relying on the designer's can, and furthermore, from the positional relationship with the light guide position and the value at both ends of light and dark. The brightness value can be set so as to be smoothly connected. Thus, a gradation pattern can be obtained by calculating luminance data in accordance with the program only by placing the light guide at a predetermined position.
Therefore, a precise gradation pattern can be obtained without the need for manual calculation and without calculation errors due to manual calculation. Further, according to the present design apparatus, in the processing of the luminance data, the luminance data is sent to, for example, image retouching software or a so-called image processing software such as Photoshop (Adobe Systems), and the software is used. It is also possible to easily correct the shading difference, and it is also possible to calculate the gradation pattern so as to obtain a screen display closer to a more natural viewing characteristic. As described above, if the calculation is performed using the calculation means, no manual calculation is required, so that the work of designing and manufacturing the gradation pattern can be saved, and the design of the gradation pattern can be made more efficient. Various programs can be set so as to obtain a precise gradation pattern by using the luminance data. Therefore, if an operation is performed in accordance with such a program, at least skill and experience can achieve a desired accuracy corresponding to the setting of the program. Can be obtained. Next, a gradation pattern designing method performed by using such a gradation pattern measuring apparatus will be described. FIG. 3 is a flowchart showing the procedure of the design method. The light guide 200 is, as shown in FIG.
For example, it is inserted at a predetermined position in the gradation pattern designing apparatus 100. As described above, the light source and the luminance detecting means may be set in a dark room, and the light guide may be arranged at a predetermined position therebetween. After being arranged as described above, light is incident on the light guide from the light source, and light is emitted from the surface side of the light guide (step S10). The light emitted from the light guide is not uniform parallel light because the light incident on the light guide undergoes an attenuating action in the light guide. In the light in this state, the luminance of the surface of the light guide is measured for each of a plurality of luminance detecting means whose positional relationship is known (step S20). A gradation pattern is calculated based on each luminance data (step S3).
0). A light guide is designed as designed based on the gradation pattern. As described above, since the brightness data array obtained by using the present measuring device indicates the brightness pattern on the surface of the light guide, the light guide is adjacent to the light source described above. It is possible to easily obtain a brightness data array corresponding to the brightness pattern of the light guide simply by arranging the light guide and light incident on the light guide. Further, since a predetermined arithmetic processing can be performed on the luminance data array, a gradation pattern of the light guide according to the arithmetic processing can be easily obtained. As the predetermined arithmetic processing, various programs can be set so as to efficiently obtain a precise light guide gradation pattern using the luminance data array. -A gradation pattern having desired accuracy corresponding to at least the setting of the program can be easily obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram according to an embodiment of the present invention. FIG. 2 is an explanatory side view showing an outline of the design apparatus according to the embodiment of the present invention. FIG. 3 is a flowchart showing an operation of the measuring device according to the embodiment of the present invention. FIGS. 4A and 4B are a plan view and a side view schematically showing a conventional light guide and a gradation pattern. FIGS. 5A and 5B are a plan view of a light guide 200 and a side view schematically showing the magnitude of luminance data. [Description of Signs] 10 light source, 20 luminance detecting means, 30 arithmetic means, 5
0: dark box, 100: design equipment

Claims (1)

Claims: 1. A light source and, when a light guide is disposed adjacent to the light source, light incident from the light source and propagating through the light guide radiates from the light guide. A plurality of brightness detection means for respectively detecting the brightness of the light guide that is generated, the light source, the light guide, and a dark box means surrounding the detection surface of the brightness detection means and being isolated from external light; Wherein the plurality of luminance detecting means have a known positional relationship with each other.