KR20070092577A - An optical sensing system and a color analyzer with the optical sensing system - Google Patents

Abstract

An optical sensing system and a color analyzer with the same are provided to improve accuracy and redundancy due to directionality of a liquid crystal display panel by using a telecentric optical system. An optical sensing system includes a condensing device(420), an optical uniformization device(430), an optical receiver(440), and a signal processing body. The condensing device condenses only a ray having a radial angle less than a predetermined value among rays irradiated from a measuring target area to one rear condensing surface. The optical uniformization device diffuses the ray condensed on the condensing surface. The optical receiver receives a part of the rays transmitted from the optical uniformization device to a rear direction and determines a received optical spectrum range. The signal processing body calculates optical and color characteristics corresponding to an optical signal received by the optical receiver.

Description

Optical sensing system and color analyzer with such optical sensing system {AN OPTICAL SENSING SYSTEM AND A COLOR ANALYZER WITH THE OPTICAL SENSING SYSTEM}

1 illustrates a typical color analyzer.

2 illustrates a typical optical sensing system.

3 illustrates another exemplary optical sensing system.

FIG. 4 is a diagram illustrating the optical branch device of FIG. 3, in which a cross section of a typical optical fiber is separately illustrated in FIG. 4A.

5 illustrates one preferred embodiment of a tristimulus type color analyzer according to the present invention.

FIG. 5A illustrates one preferred embodiment of the optical sensing system of FIG. 5.

FIG. 5B illustrates a preferred arrangement embodiment of the optical receiver in FIG. 5A.

6 illustrates a second embodiment of an optical sensing system in accordance with the present invention.

7 illustrates a third embodiment of an optical sensing system in accordance with the present invention.

8 illustrates a fourth embodiment of an optical sensing system in accordance with the present invention.

FIG. 8A illustrates another preferred embodiment of the lighting device of FIG. 8. FIG.

<Explanation of symbols for main parts of the drawings>

MR: Area to be measured

400: optical sensing system

420: condenser

422: first lens

424: aperture

430: light homogenizing device

440: light receiving device

The present invention relates to an optical sensing system and a color analyzer comprising the system, and more particularly, to an optical sensing system capable of measuring optical and color characteristics of a flat panel display device and a color analyzer including such an optical sensing system.

Electromagnetic waves in the wavelength range of 380 nm to 780 nm form the human eye's visual acuity and are called visible light. In the wavelength range, the human eye detects various different colors such as purple, indigo blue, blue, green, yellow, orange, and red. In 1931, the International Commission on Illumination (CIE) enacted three stimulus XYZ methods to visualize the human eye, displaying color values in various colors, such as digital cameras, displays, and printers. The color display of various color related devices is defined.

Referring to FIG. 1, this figure illustrates a typical color analyzer 1. The color analyzer 1 includes a probe 10 and a signal processing main body 20, and is equipped with an optical sensing system (not shown) inside the probe 10. The optical sensing system receives the light beam of the measurement target region MR of the display panel 2 and converts the received light beam into an electrical signal. The electrical signal is transmitted to the signal processing body 20 through the electric line 30 and processed to analyze the optical and color characteristics of the display panel 2.

Referring to FIG. 2, this figure illustrates a typical optical sensing system 100. The optical sensing system 100 includes a lens 120, a light receiving device 140, and a shot optical device 160. Here, the light receiving device 140 includes a diffuser plate 142, three light spectrum crystal filter plates 144, and three light receivers 146 arranged in parallel. The diffuser plate 142 is located in the focusing plane behind the lens 120, the light spectrum correcting filter plate 144 is located behind the diffuser plate 142, and the three light receivers 146 are corresponding light spectrum correcting filter plates. Respectively located behind 144. The light beam emitted from the measurement target region MR is imaged on the diffuser plate 142 via the lens 120 and then to the optical receiver 146 via the light spectrum correction filter plate 144. Let each be received.

The optical lens device 160 includes a first light reflection surface 162 and a second light reflection surface 164. Here, the first light reflection surface 162 is located on the optical axis A of the lens 120 and has an angle of 45 degrees with the optical axis A. FIG. The light rays from the measurement target region MR are reflected by the second light reflection surface 164 via the first light reflection surface 162. The light beams reflected by the second light reflection surface 164 are parallel to the direction of the optical axis A to allow the user to observe the range of the measurement target region MR.

In order to achieve a suitable amount of color, the three light spectral correction filter plates 144 use the XYZ tristimulus values defined by the International Illumination Committee to determine the corresponding optical spectral response function of the corresponding light receiver 146 by the International Illumination Commission. Make it equal to the function. As a result, the electrical signals output from the three optical receivers 146 display the XYZ tristimulus values of the measurement target region MR, respectively.

It should be noted that, as shown in FIG. 2, the light rays emitted at different positions of the measurement target area MR are incident on the optical sensing system 100 and the radiation angles received by the optical receiver 146 are the same. It is not. For example, the radiation angle a1 at which the light beam emitted at position P1 can be received by the light receiver 146 is biased downward in the normal direction of the display panel. However, the radiation angle a2 at which the light rays emitted at position P2 can be received by the light receiver 146 is biased above the normal direction of the display panel. In conventional cathode ray tube displays with little directionality, the radiation angle difference does not affect the measurement results. However, in the liquid crystal display panel and the flexible display which have a distinct directionality, such a difference may significantly affect the accuracy of the measurement result.

Next, in the diameter optical device 160 of the optical sensing system 100 illustrated in FIG. 2, the first light reflection surface 162 is installed on the optical axis A of the lens 120. The presence of the first light reflecting surface 162 significantly reduces the total amount of light that the light receiving device 140 can receive and affects the light quantity utilization of the optical sensing system 100.

Referring to FIG. 3, this figure illustrates another exemplary optical sensing system 200. The optical sensing system 200 is disclosed in Taiwan Patent No. 535004. As shown in the figure, the optical sensing system 200 has a lens 220, an optical branch device 230, and a light receiving device 240. The optical branch device 230 includes one light incident surface 230a and three light emitting surfaces 230b. Here, the light incident surface 230a is located at the focusing plane of the lens 220 to receive the light rays from the lens, and the three light exit surfaces 230b are the three light spectrum correction filter plates of the light receiving device 240 ( Aim each of 244 to provide a light beam to the optical receiver 246. In addition, as shown in Figure 4, the optical branch device 230 is composed of an optical fiber beam. In the light incident surface 230a, the optical fiber beams may be divided into six equal parts, such as A1, A2, A3, A4, A5, and A6. Among them, the optical fiber beams located at the opposite side, for example, A1 and A4, extend to the same light exit surface 230b.

It should be noted that the light incident surface 230a of the optical branch device 230 and the lens 220 constitute a telecentric optical system, and thus the light entrance surface 230a and the lens 220 are formed from different positions in the measurement target region MR. The radiation angles b of light rays incident on the optical surface 230a are made substantially the same. Therefore, the problem that the radiation angles of the measurement target region MR existing in the optical sensing system 100 are not described above does not exist in the optical sensing system 200.

However, as shown in FIG. 4, the optical branch device 230 is composed of an optical fiber beam, and voids g which cannot transmit light rays are necessarily present between individual circular optical fibers. In addition, looking at the cross section of the optical fiber 300, as shown in Figure 4 (A), the optical fiber 300 may be divided into a core 310, a clad 320 and the outer coating layer 330. Here, the area of the core 310 that transmits the light beam generally occupies only one quarter of the cross-sectional area of the optical fiber 300. Accordingly, only less than a quarter of the light rays incident on the light incident surface 230a through the lens 220 may be incident on the light receiver 246, which may seriously affect the light utilization rate of the optical sensing system 200. Affects.

Next, since the optical branch device 230 must form a beam by closely gathering a very large number of optical fibers, its fabrication is difficult and the cost is high. If the quantity of the optical fiber is reduced, the manufacturing cost can be reduced, but the void (g) between each optical fiber is increased, which leads to a decrease in the light utilization rate.

Therefore, in the condition of securing measurement accuracy, how to effectively and simultaneously consider the light utilization rate and manufacturing cost to meet the low luminance measurement requirements has emerged as an important problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color analyzer for solving a problem that is difficult to measure due to the directionality of a liquid crystal display panel by solving a problem in which a radiation angle of light rays incident on an optical sensing system from a measurement target region is inconsistent.

Another object of the present invention is to provide a color analyzer that can solve the problem that low light quantity measurement is difficult by effectively using the light incident on the optical sensing system.

The color analyzer provided by the present invention includes an optical sensing system that acquires light rays emitted from the measurement target region by aiming at one measurement target region on the display panel. The optical sensing system includes a light collecting device, a light homogenizing device and a light receiving device. Here, the light converging device focuses only the light rays whose radiation angles are smaller than a predetermined angle among the light rays emitted from the measurement target region in one rear focusing plane. The optical homogenizing device is located in the focusing plane, diffuses and mixes the light rays focused on the focusing plane, and projects it uniformly backwards within a predetermined first angle range. The light receiving device is located behind the light homogenizing device and serves to receive the light beam projected backward from the light homogenizing device.

The light collecting device includes a lens and an aperture. Here, the lens serves to focus a specific light beam emitted from the measurement target region on the focusing plane behind the lens. The aperture is located at the rear of the lens and at the focusing plane, and also includes the aperture stop. As a result, only light rays having a radiation angle smaller than a predetermined second angle among the light rays emitted from the measurement target region are transmitted to the aperture stop and imaged on the focusing plane.

In an embodiment of the invention the optical homogenizer is a holographic diffuser.

In another embodiment of the invention, the optical sensing system further comprises an illumination device. The lighting device may move in the focusing plane behind the light collecting device to illuminate the measurement target area.

Advantages and spirit of the present invention will be more clearly understood by reference to the following detailed description and the accompanying drawings.

Figure 5 is a block diagram of a preferred embodiment of a three stimulus type color analyzer according to the present invention. The color analyzer includes an optical sensing system 400 and a signal processing body 500. The optical sensing system 400 aims at the measurement target area MR on the display panel to acquire a light beam from the measurement target area MR and converts the light beam into an electrical signal. The electrical signal is transmitted to the signal processing main body 500 through an electric line and calculated to measure and analyze optical and color characteristics of the display panel.

FIG. 5A is an enlarged view of the optical sensing system 400 of FIG. 5. As shown in the figure, the optical sensing system 400 includes a light collecting device 420, a light homogenizing device 430, and a light receiving device 440. In this case, the light concentrating device 420 collects a specific light beam emitted from the measurement target region on the focusing plane FS1 behind the light beam. The light homogenizing device 430 is positioned on the focusing plane FS1 to diffuse and mix the light rays collected on the focusing plane FS1, and uniformly toward the rear in a predetermined first angle x. To be projected. The light receiving device 440 is located at the rear of the light homogenizing device 430 and serves to receive the light beams transmitted backward from the light homogenizing device 430.

The light collecting device 420 includes a first lens 422 and an aperture 424. Here, the first lens 422 serves to focus a specific light beam from the measurement target region MR on the focusing plane FS1 behind it. The aperture 424 is positioned at the focusing plane FS1 behind the first lens 422 and aims at the optical axis A1 of the first lens 422. An aperture stop (AS) of the aperture 424 blocks unnecessary light rays to determine light rays that can enter the light homogenizing device 430.

It should be noted that the light concentrating device 420 constitutes a telecentric optical system, and among the light rays emitted from the measurement target region MR of the display panel, the radiation angle is a predetermined second angle y. Only smaller light rays pass through the aperture stop AS and are collected at the focusing plane FS1 to be incident on the light homogenizing device 430. In other words, the light converging device 420 is projected at different positions of the measurement target region MR so that the light beams incident on the light homogenizing device have the same incident angle y. In addition, thereby, the optical sensing system 400 according to the present invention can be applied to color analysis of the liquid crystal display panel having a clear orientation.

The light receiving device 440 includes a second lens 442, three light receivers 446 and three light spectrum crystal filter plates 444 arranged in parallel. The second lens 442 is positioned behind the optical homogenizer 430, and the distance from the optical homogenizer 430 is one times the focal length f2 of the second lens 442. In other words, the light homogenizing device 430 is located in the focusing plane in front of the second lens 442. Light rays projected toward the rear by the light homogenizing device 430 are converted into parallel light rays through the second lens 442 and then projected onto the light spectrum correcting filter plate 444 and the light receiver 446. It should be noted that the optical spectrum correction filter plates 444 are disposed in front of the individual optical receivers 446, and the three optical spectrum correction filter plates 444 correspond to the tristimulus values XYZ, respectively. Determine the light spectral range that can be received.

In order to make the amount of light incident on the individual light spectrum crystal filter plates 444 as equal as possible, three optical receivers 446 arranged in parallel when viewed from the optical axis A2 direction of the second lens 442, as shown in FIG. 5B. ) And a corresponding light spectrum correcting filter plate 444 are arranged with the optical axis A2 of the second lens 442 centered on the symmetry.

The light homogenizing device 430 is a holographic diffuser, which allows light rays collected on a focusing plane to be sufficiently diffused and mixed to be projected backwards within a predetermined first angle x. have. Not only can the light amount after diffusion be uniformly distributed by the characteristics of the optical homogenizer, but also the diameter of the light receiving surface of the optical homogenizer is smaller than the diameter of the second lens 442. The homogenizing device can be viewed as a device which can obtain a more excellent homogenizing effect by diffusing the amount of light received by the receiving surface back again in a manner similar to the ideal point light. In addition, in order that the light homogenizing device 430 may be received by the optical receiver 446 as long as it is a light beam projected toward the rear, the predetermined first angle x must be the size of the second lens 442 and the same. It should be adjusted to the focal length f2. In addition, the predetermined first angle x may be somewhat changed when the means used by the optical homogenizing device are different. In a preferred embodiment according to the invention, the predetermined first angle x is greater than 10 degrees and preferably has a range between 15 and 25 degrees.

It should be noted that the above-described holographic diffuser plate is merely a preferred embodiment of the optical homogenization apparatus of the present invention. The optical homogenization apparatus according to the present invention may be implemented using an optical fiber, an optical fiber beam, a light guide tube, or an optical element having a similar material, shape, and configuration. For example, by arranging the optical fiber and the optical beam similarly according to the size and appearance of the holographic diffuser, and designing similarly to the holographic pack diffuser, the purpose of collecting light and radiating the light toward the rear according to a specific angle Can be achieved. In addition to the above-described design method, the light guide tube may employ a funnel-shaped light guide tube, the area of which the light incident surface corresponds to the holographic diffuser and the area of the light emitting surface being the second. Corresponds to the lens 442.

With reference to FIG. 6, this figure illustrates a second embodiment of an optical sensing system in accordance with the present invention. In contrast to receiving optical signals corresponding to XYZ tristimulus values using the three light spectral correction filter plates 444 and three light receivers 446 in the embodiment shown in FIG. 470 was used with photodetectors 474 such as light emitting diodes, linear and planar charge coupling devices (CCD). As shown in the figure, a light spectrum correction filter plate 472 corresponding to the XYZ tristimulus value is disposed on the rotary wheel 470. The rotation of the rotary wheel 470 allows the photodetector 474 to sequentially record the light spectrum corresponding to the XYZ tristimulus values. Note that the rotation wheel 470 may be installed not only in front of the second lens 442 but also in the rear of the second lens 442.

Referring to FIG. 7, this figure illustrates a third embodiment of an optical sensing system according to the present invention. This embodiment uses spectroscopy device 482 instead of light spectral correction filter plate 472. A spectroscopic device 482, such as a light grid, divides the incident light into outgoing light having different emission angles according to the wavelength, and then detects the outgoing light with an appropriate photodetector 484 to correspond to an XYZ tristimulus value. Can be obtained.

In order to provide a convenience for a user to check the detection position of the optical sensing system 400, that is, the position of the measurement target region MR on the display panel, the fourth embodiment of the optical sensing system according to the present invention moves as shown in FIG. 8. Possible lighting devices 450 are installed. The illumination device 450 is moved in the focusing plane FS1 behind the first lens 442 to illuminate the measurement target area MR by aiming the direction of the optical axis A1 of the first lens. In a preferred embodiment, when the illumination device 450 illuminates the measurement target area MR, the light beam from the measurement target area MR is blocked and cannot enter the light homogenization device 430. In addition, as shown in FIG. 8, the illumination device 450 and the aperture 424 may be installed in one switching device 460 to illuminate the measurement target region MR through the switching operation of the switching device 460. Whether the light beam from the measurement target region MR is incident on the optical homogenizer 430 or not. In addition, as shown in FIG. 8A, in another preferred embodiment of the lighting device, the aperture 424 and the lighting device 450 ′ may be separately installed. Here, the position of the aperture 424 is fixed, only the illumination device 450 ′ is movable, and it is determined whether to illuminate the measurement target region MR.

Compared to the conventional optical sensing system shown in FIG. 2, the present invention utilizes a telecentric optical system so that light rays received by the optical sensing system 100 from different positions of the measurement target region MR may be reduced. By having the same emission angle, the orientation of the liquid crystal display panel is prevented from adversely affecting the accuracy and redundancy of the measurement results. At the same time, the present invention allows the total amount of light that the light receiver 446 can receive by using the movable illumination device 450 instead of the optical lens device 160 shown in FIG. 2. As a result, the light quantity utilization rate of the optical sensing system according to the present invention may be improved.

Compared with the conventional optical sensing system 200 shown in FIG. 3, since the present invention uses the optical homogenizing device 430, it is not necessary to use the optical branch device 230 having a high manufacturing cost, thereby greatly reducing the manufacturing cost. can do. Next, although light is provided to the optical receiver 246 in a total reflection manner in the optical fiber of the optical branch device 230, only less than a quarter of the light can be incident on the core of the optical fiber (Fig. 4). And (A) of FIG. 4 simultaneously. In contrast, in the optical sensing system 400 according to the present invention, the light rays passing through the aperture 424 are sufficiently provided in the holographic diffuser plate and then provided to the light receiver 446. Therefore, it is possible to provide a desirable light amount utilization.

The foregoing has described the present invention in detail using preferred embodiments, and is not intended to limit the scope of the present invention. Those skilled in the art can appropriately make very small changes and adjustments without departing from the spirit of the invention, which is also within the scope of the invention.

Claims (10)

An optical sensing system for acquiring light rays emitted from an area to be measured by aiming at one area to be measured on a display panel, A light concentrating device for concentrating only one light beam having a radiation angle smaller than a predetermined angle among light rays emitted from the measurement target region in one rear converging plane; And Located in the focusing plane, the light homogenizing device for diffusing the light rays collected on the focusing plane Optical sensing system comprising a. The method of claim 1, The light collecting device, A first lens for imaging the measurement target region on a focusing plane behind the lens; Only one light beam installed in the focusing plane and including an aperture stop and having a radiation angle smaller than a predetermined second angle among the light rays emitted from the measurement target region passes through the aperture stop. And an aperture for imaging in the focus plane. In the color analyzer of the three stimulus value for measuring the optical characteristics and color characteristics of the display panel, A light concentrating device for converging light rays emitted from the measurement target region to one rear focusing plane; A light homogenizing device positioned in the focusing plane and configured to diffuse the light beams focused on the focusing plane and to be uniformly transmitted backwards within a predetermined first angle range; An optical receiver located behind the optical homogenizer, comprising three or three or more parallel optical receivers for receiving some light beams projected rearward from the optical homogenizer, and corresponding optical receivers A light receiving device, each positioned in front and comprising three or more light spectral correction filter plates that determine the light spectral range received from the light receiver by the tristimulus values; And Signal processing body for calculating the corresponding optical and color characteristics by the optical signal received from the optical receiver Tri-stimulus color analyzer comprising a. The method of claim 3, And a lighting device which is moved in the focusing plane of the light collecting device and illuminates the measurement target area. The method of claim 3, The light collecting device, A first lens for collecting the light rays emitted from the measurement target region; An aperture installed in the focusing plane and including an aperture stop, so that only a ray having a radiation angle smaller than a predetermined second angle among the rays emitted from the measurement target region passes through the aperture stove; Tri-stimulus color analyzer comprising a. The method of claim 3, And said light collecting device comprises a telecentric optical system. The method of claim 3, And the optical homogenizer is a holographic diffuser. The method of claim 3, The light receiving device further includes a second lens, The optical homogenizer is located in the focusing plane in front of the second lens, And the second lens converts all the light beams projected rearward from the light homogenizing device into parallel light beams and projects the light beams onto the plurality of optical receivers. The method of claim 3, And switching to the aperture so as to block light rays from the area to be measured and to illuminate the area to be measured. The method of claim 3, And said predetermined first angle is greater than 10 degrees.

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