JP2007024763A - Optical measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure brightness without taking time, even if a sensor having no high sensitivity is used. <P>SOLUTION: The optical measuring device 1 comprises an integral sphere 10, having an opening part 17 introducing light in the inside and an inner face 18 capable of reflecting light, a plurality of light introducing means for introducing light advanced from a plurality of measuring spots 14, 15 and 16, respectively, and a measuring instrument 11 for measuring the light amount, by receiving light reflected on the inner face 18 in the inside of the integral sphere 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical measuring apparatus used when measuring surface luminance of a liquid crystal display panel or the like and temporal changes in surface luminance.

  In the development of liquid crystal display panels, surface brightness is one of the evaluation items for display performance. In order to evaluate the surface luminance, measurement is performed by an optical measuring device in a state where display contents of the liquid crystal display panel are set according to designated conditions.

  An example of a conventional measurement is shown in FIG. The surface 2 to be measured is a screen of a liquid crystal display panel. The optical measuring device 51 includes a lens 56 and a measuring instrument 11. In the optical measuring device 51, the light emitted from the measurement spot 54 on the surface to be measured 2 is collected by the lens 56 and received by the measuring instrument 11. The measuring device 11 is also called a luminance meter, and plays a role of deriving luminance from the amount of received light.

In recent years, liquid crystal display panels have improved display quality by aiming to improve contrast and increase surface brightness. For this reason, the display luminance range has been greatly expanded as compared with the conventional case, and the measurement range is required to be sufficiently wide as an optical measurement apparatus. In particular, when measuring a “black screen whose luminance is as close to 0 as possible,” which is important in image expression, luminance such as 1 cd / cm ² or less is measured, and the amount of light received by the optical measuring device is extremely small. A sensor with extremely high sensitivity is required. In addition, when a sensor whose sensitivity is not sufficiently high must be used, there is a method of measuring after increasing the absolute amount of light by integrating the received light. The measurement time becomes long, such as several tens of seconds per measurement.

As an example of integrating light, Japanese Patent Application Laid-Open No. 58-103624 (Patent Document 1) discloses a technique for measuring the luminance distribution and chromaticity distribution of a surface to be measured. In the apparatus disclosed in this document, a light-shielding plate having a minute hole is provided so as to be movable in the imaging plane, and light that is selectively extracted from the imaging plane through the minute hole is inputted. It is configured to integrate with an integrating sphere. In this apparatus, the brightness distribution and the chromaticity distribution of the surface to be measured are obtained by moving the light shielding plate and scanning the microscopic holes in the imaging plane.
JP 58-103624 A

  In any case, integration by the conventional method takes a long time per measurement, which is inappropriate when it is desired to measure the temporal change in surface luminance. The technique of Patent Document 1 also takes time in that scanning is performed by moving the light shielding plate. In addition, the fact that it takes time for one measurement impairs the convenience of measurement and lowers the work efficiency.

  On the other hand, in order to procure sufficiently sensitive sensors, it has been difficult to develop new sensors.

  Therefore, an object of the present invention is to provide an optical measurement device that can measure luminance without taking time even if a sensor that is not highly sensitive is used.

  In order to achieve the above object, an optical measurement apparatus according to the present invention includes an integrating sphere having an opening for entering light and an inner surface capable of reflecting light, and light traveling from a plurality of measurement spots. And a plurality of light guiding means for guiding the light to the opening, and a measuring device for measuring the amount of light by receiving the light reflected by the inner surface inside the integrating sphere.

  According to the present invention, since the light from a plurality of measurement spots is collected by the light guiding means and taken into the integrating sphere to obtain a sufficient amount of light, it is configured to receive the light with a measuring instrument. Even if is used, it is possible to realize an optical measuring device that can measure luminance without taking time.

(Embodiment 1)
(Constitution)
With reference to FIG. 1 and FIG. 2, the optical measuring device 1 in Embodiment 1 based on this invention is demonstrated. As shown in FIG. 1, the optical measuring apparatus 1 includes an integrating sphere 10 having an opening 17 for entering light and an inner surface 18 capable of reflecting light, and a plurality of measurement spots 14, 15, 16. A plurality of light guiding means for guiding the respectively traveling light to the opening 17 and a measuring instrument 11 for measuring the light quantity by receiving the light reflected by the inner surface 18 inside the integrating sphere 10. Prepare. Here, the plurality of light guiding means includes a plurality of mirrors 3, 4, 5 and a plurality of lenses 6, 7, 8. The plurality of mirrors 3, 4, 5 are for reflecting the light traveling from the measurement spots 14, 15, 16 toward the integrating sphere 10. The plurality of lenses 6, 7, and 8 are for collecting the light that is reflected by the plurality of mirrors 3, 4, and 5 and travels toward the integrating sphere 10 in the opening 17. The distance from the mirrors 3, 4, 5 to the opening 17 is substantially equal to the focal length of each lens. The inner surface 18 of the integrating sphere 10 is coated with a white paint such as barium sulfate that has a high diffuse reflectance and does not substantially absorb light.

  The plurality of measurement spots 14, 15, and 16 are a plurality of regions in the flat measured surface 2, each having a diameter of about several centimeters. Preferably, the plurality of mirrors 3, 4, 5 are respectively arranged in the normal direction of the surface to be measured 2 when viewed from the plurality of measurement spots 14, 15, 16. Mirrors 3, 4, and 5 are disposed at a distance of several tens of centimeters from the surface to be measured 2 in the normal direction. Light emitted from the measurement spot 14 in the normal direction is reflected by the mirror 3, passes through the lens 6, and enters the opening 17. The light emitted from the measurement spot 15 in the normal direction is reflected by the mirror 4, passes through the lens 7, and enters the opening 17. Light emitted from the measurement spot 16 in the normal direction is reflected by the mirror 5, passes through the lens 8, and enters the opening 17. These three optical paths are respectively secured, and the mirrors 3, 4, 5 and the lenses 6, 7, 8 are respectively arranged at positions that do not disturb the other optical paths.

  More preferably, the optical measurement apparatus 1 includes a light shielding plate 9 disposed outside the opening 17, and the light shielding plate 9 has a minute hole 9 a smaller than the opening 17 at a position overlapping the opening 17. FIG. 2 shows an enlarged cross section near the opening 17 in FIG. The light shielding plate 9 is in close contact with the opening 17 of the integrating sphere 10. The micro hole 9a is a through hole having a diameter of several mm or less. When the optical measuring device 1 includes such a light shielding plate 9, the above-described light guiding means is for guiding light to the opening 17 through the minute hole 9a. Therefore, the light guiding means should adjust the positional relationship so that the light necessary for the measurement from each measurement spot just passes through the minute hole 9a. The distance from the lenses 6, 7, 8 to the minute hole 9 a is preferably set to the focal length of each lens.

(Action / Effect)
In the optical measurement apparatus 1 in the present embodiment, the light of a plurality of measurement spots is simultaneously taken into the integrating sphere 10 by the light guiding means, and the result obtained by adding or integrating these lights by the integrating sphere 10 is received by the measuring instrument 11. Therefore, the amount of light incident on the measuring instrument 11 can be increased even if the light to be measured 2 itself is weak. In this embodiment, the number of measurement spots is 3, and three mirrors and lenses are prepared. However, the number of measurement spots may be any number other than 3 as long as it is 2 or more. The larger the number, the more light can be guided into the integrating sphere 10, and the amount of light incident on the measuring instrument 11 can be increased, which is preferable.

  In the present embodiment, since the light shielding plate 9 having the minute hole 9a smaller than the opening 17 is provided, the light unnecessary for the measurement deviates from the position of the minute hole 9a and is shielded by the light shielding plate 9, so that the measurement is truly performed. Only the necessary light passes through the microhole 9 a and enters the integrating sphere 10 from the opening 17.

  When measuring the luminance of the surface to be measured that emits light uniformly, according to the present invention, the area of the measurement spot can be easily enlarged. Even in low-luminance measurement where the radiated light of the object to be measured is weak, according to the present invention, the amount of light received by the sensor can be easily increased to a level that can be detected by the sensor. Even if it is, it becomes possible to lower the measurement lower limit. Moreover, it does not take much time to increase the amount of light received by the sensor.

  Even if the light emitted from the surface to be measured is polarized, in the present invention, the light is irregularly reflected in the integrating sphere, whereby the polarization error can be suppressed.

  In general, when the sensitivity of a sensor is increased, noise increases. However, according to the present invention, increase in sensor noise can be avoided.

  In the beginning of this specification, the luminance measurement of the liquid crystal display panel has been described as an example of the purpose of use of the optical measurement device. However, the optical measurement device according to the present invention is not limited to the measurement of the luminance of the liquid crystal display panel, and has a wide area. It can be widely used for general purposes of measuring the amount of light emitted from the surface of the object it has.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

It is a conceptual diagram of the optical measuring device in Embodiment 1 based on this invention. It is a partial expanded sectional view of the optical measuring device in Embodiment 1 based on this invention. It is a conceptual diagram of the luminance measurement based on a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,51 Optical measuring apparatus, 2 surface to be measured, 3, 4, 5 mirror, 6, 7, 8, 56 lens, 9 light-shielding plate, 9a micropore, 10 integrating sphere, 11 measuring instrument, 14, 15, 16, 54 Measurement spot, 17 (integral sphere) opening, 18 (integral sphere) inner surface.

Claims (5)

An integrating sphere having an opening for entering light and an inner surface capable of reflecting light;
A plurality of light guiding means for guiding the light respectively traveling from a plurality of measurement spots to the opening;
An optical measuring device comprising: a measuring device for measuring the amount of light by receiving the light reflected by the inner surface inside the integrating sphere.   The optical measurement apparatus according to claim 1, wherein the light guiding unit includes a plurality of mirrors for reflecting light traveling from a measurement spot toward the integrating sphere.   The optical measurement apparatus according to claim 2, wherein the light guiding unit includes a lens that collects light that is reflected by the mirror and travels toward the integrating sphere at the opening.   The plurality of measurement spots are a plurality of regions in a flat surface to be measured, and the plurality of mirrors are respectively disposed in a normal direction of the surface to be measured as viewed from the plurality of measurement spots. The optical measuring device according to claim 2 or 3.   A light-shielding plate disposed outside the opening, wherein the light-shielding plate has a microhole smaller than the opening at a position overlapping the opening, and the light guiding means passes through the microhole. The optical measuring device according to claim 1, wherein the optical measuring device is for guiding light to the light source.

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