JP2012208181A - Contrast inspection device - Google Patents

Abstract

An object of the present invention is to inspect the contrast of a liquid crystal panel 10 used for a light valve of a projector without using a screen.
Light emitted from a light source 110 is collected by an incident side condensing lens 32, and an S direction component of the light is transmitted through a polarization beam splitter 40 and irradiated to a part of a liquid crystal panel 10. Of the light reflected by the liquid crystal panel 10, the P-direction component is reflected by the polarization beam splitter 40, condensed by the output side condenser lens 34, and guided to the light receiving unit 120. The inspection unit acquires the illuminance information when the white image is displayed on the liquid crystal panel 10 and the illuminance information when the black image is displayed from the light receiving unit 120 and inspects the contrast of the liquid crystal panel 10.
[Selection] Figure 2

Description

  The present invention relates to a contrast inspection apparatus for inspecting the contrast of a liquid crystal panel used for a light valve of a projector, for example.

  The liquid crystal panel is used as a light valve of a projector in addition to a display device of an electronic device. In the projector, a modulated image of about 1 inch diagonally is generated by the liquid crystal panel, and this image is enlarged and projected onto the screen. Since the modulation image generated by the liquid crystal panel is very small, when inspecting the liquid crystal panel, a technique for inspecting an image enlarged and projected on the screen by visual observation or image analysis is proposed in the same manner as an actual machine ( For example, see Patent Document 1).

JP 2004-94140 A

However, in order to inspect the image projected on the screen, a large space for installing the screen is required, so the installation location of the inspection apparatus is limited.
The present invention has been made in view of the above circumstances, and one of its purposes is to provide a technique capable of inspecting the contrast of a liquid crystal panel without using a screen.

  In order to achieve the above object, in the contrast inspection apparatus according to the present invention, the light source and the light emitted by the light source are condensed into a first light flux and irradiated onto a part of the liquid crystal panel. An optical member that condenses the light emitted from the liquid crystal panel into a second light flux and guides it to the light receiving portion; an inspection portion that inspects the contrast of the liquid crystal panel based on the second light flux guided to the light receiving portion; It is characterized by comprising. According to the present invention, the light from the light source is condensed into the first light flux and applied to a part of the liquid crystal panel, and the light emitted from the liquid crystal panel (transmitted light or reflected light) is collected into the second light flux. Since the light is guided to the light receiving portion, a screen and a space for installing the screen are not required. In addition, since the light from the light source is condensed into the first light flux and applied to a part of the liquid crystal panel, a light source with low cost and low power consumption can be used.

In the present invention, it is preferable that the ratio of the first light beam irradiated to a part of the liquid crystal panel and the second light beam guided to the light receiving unit is 1: 1. According to this configuration, since the light receiving unit enters the emitted light from the liquid crystal panel almost as it is, the liquid crystal panel can be appropriately inspected.
Moreover, the aspect whose said light source is LED is also preferable. In the present invention, the liquid crystal panel is irradiated with light condensed on a part rather than the entire surface. For this reason, even an LED whose output is relatively weak compared to other lamps can be irradiated with a luminous flux equivalent to that of a halogen lamp or a xenon lamp.
Here, as the optical member, if the liquid crystal panel to be inspected is a reflection type, the incident side polarizer, the incident side condensing lens, the polarization beam splitter, the phase difference compensator, the output side polarizer, and the output side collector An aspect including an optical lens is preferable, and an aspect including an incident side polarizer, an incident side condensing lens, an output side polarizer, and an output side condensing lens is preferable as long as it is a transmission type.

It is a perspective view which shows the structure of the liquid crystal panel used as a test object. It is a figure which shows the optical structure of the contrast inspection apparatus which concerns on 1st Embodiment. It is a block diagram which shows the structure of the contrast inspection apparatus which concerns on 1st Embodiment. It is a figure which shows the optical structure of the contrast inspection apparatus which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a configuration of a liquid crystal panel 10 to be inspected in the contrast inspection apparatus according to the embodiment. The liquid crystal panel 10 is a reflection type used as a light valve of a projector, and the display unit body 12 reflects light incident from the upper side in the drawing to generate a modulated image. The display unit main body 12 is casing in a frame 14 that is opened at a portion where a modulated image is generated.

As is well known, the display unit main body 12 has an electrode formation surface in which an element substrate having individual pixel electrodes for each of a plurality of pixels and a counter substrate having a common electrode common to the plurality of pixels maintain a certain gap. Are bonded so as to face each other, and a liquid crystal is sandwiched between the gaps.
One end of an FPC (Flexible Printed Circuits) substrate 20 is connected to the display unit main body 12. A bare chip driver IC 22 is mounted on the FPC board 20 by COF (Chip On Film) technology, and connected to the display unit main body 12 and provided with a plurality of terminals 26 in the terminal unit 24 on the side opposite to one end. Yes. When the terminal unit 24 is connected to a connector of an inspection unit to be described later and various control signals and video signals are supplied from the inspection unit via the plurality of terminals 26, the driver IC 22 drives the display unit body 12. Thus, the display unit main body 12 is configured to generate a modulated image corresponding to the video signal.

FIG. 2 is a schematic diagram showing an optical system of the contrast inspection apparatus 1 according to the first embodiment.
The contrast inspection apparatus 1 includes a light source 110, an optical member, and a light receiving unit 120. The optical member includes an incident side condensing lens 32, an incident side polarizer 52, a polarization beam splitter 40, a phase difference compensation plate 60, and an emission side. The configuration includes a polarizer 54 and an exit-side condensing lens 34.
In such a configuration, the liquid crystal panel 10 to be inspected is set so that the incident surface (outgoing surface) faces downward with respect to the optical axis 30a of the incident-side condenser lens 32 at the position shown in the figure.

The light source 110 outputs light toward the liquid crystal panel 10, and an LED (Light Emitting Diode) is used in the present embodiment. The diaphragm 72 restricts the light beam output from the light source 110 to a part. The incident side condensing lens 32 receives diffused light emitted from the light source 110 and condenses it toward the liquid crystal panel 10.
The incident side polarizer 52 transmits light in one direction, for example, an S direction component which is a transmission component of the next polarizing beam splitter among incident light. The polarization beam splitter 40 transmits the S-direction component light that has passed through the incident-side polarizer 52 and reflects the P-polarization component light. For example, a wire grid polarizing film is used. Here, the reflecting surface of the polarizing beam splitter 40 is set at 45 degrees counterclockwise with respect to the optical axis 30a in the drawing.

The phase difference compensation plate 60 compensates the phase difference of the liquid crystal panel 10 according to the rotation angle about the optical axis 30a. Actually, the actuator 62 rotates the phase difference compensation plate 60.
In the present embodiment, the incident-side condenser lens 32 and the diaphragm 72 are adjusted so that the diameter φa of the light beam incident on the liquid crystal panel 10 is smaller than the display size in the display unit body 12. For this reason, light enters only a part of the pixels of the display unit main body 12.

The exit side polarizer 54 provided in the 3 o'clock direction (reflection side) in the drawing with respect to the polarization beam splitter 40 transmits light in the P direction component which is a reflection component of the polarization beam splitter 40. The exit side condensing lens 34 receives the light beam reflected by the liquid crystal panel 10 and the polarization beam splitter 40 and condenses it toward the light receiving unit 120. The optical axis 30b of the exit side condensing lens 34 is set at, for example, 90 degrees on the reflecting surface of the polarization beam splitter 40 with respect to the optical axis 30a.
The light receiving unit 120 includes a sensor 122. The sensor 122 detects, for example, the illuminance (the amount of light flux per unit area) of the light received on the light receiving surface, and outputs the illuminance information. In this embodiment, the diameter φb of the light beam incident on the sensor 122 is the same as the diameter φa of the light beam incident on the liquid crystal panel 10, that is, the light beam incident on the sensor 122 is the same as the light beam incident on the liquid crystal panel 10. Thus, the exit side condensing lens 34 is adjusted.

In such a configuration, the light emitted from the light source 110 spreads as the distance from the light source 110 increases. It will be. Of the light emitted from the incident side condensing lens 32, only the S direction component passes through the incident side polarizer 52 and the polarizing beam splitter 40, and passes through the phase difference compensator 60 to the liquid crystal panel 10 with a diameter φa. Incident with a luminous flux of.
The light incident on the liquid crystal panel 10 is reflected while being modulated. At this time, the reflected light has a spread again. The reflected light of the liquid crystal panel 10 enters the polarization beam splitter 40 through the phase difference compensation plate 60 again. Of this incident light, only the P-polarized light component is reflected and transmitted through the output-side polarizer 54. Although this transmitted light has a spread, when it enters the exit-side condensing lens 34, it condenses as it goes toward the light receiving unit 120, and enters the sensor 122 with a light beam having the same diameter as the liquid crystal panel 10. .

FIG. 3 is a diagram showing an electrical configuration of the contrast inspection apparatus 1.
As shown in the figure, the inspection unit 80 includes a connector 82. When the terminal portion 24 of the liquid crystal panel 10 to be inspected is connected to the connector 82, the inspection portion 80 operates as follows.
That is, the inspection unit 80 first displays, for example, a white image in which all of the pixels are white pixels on the liquid crystal panel 10 in which the terminal unit 24 is connected to the connector 82, and then a black image in which the pixels are black pixels. A video signal and a control signal for displaying the image are supplied. Secondly, the inspection unit 80 applies the illuminance information when the white image is displayed and the illuminance information when the black image is displayed from the light receiving unit 120 (sensor 122) to the displayed black image. Find the brightness ratio of the white image. Third, the inspection unit 80 operates the actuator 62 to rotate the phase difference compensation plate 60 by a minute angle (for example, 0.2 degrees) with respect to the optical axis in a predetermined direction (for example, clockwise as viewed from the light source 110). Let Thereafter, the inspection unit 80 repeats the first to third operations until the ratio reaches the maximum value. When this operation is repeatedly executed, the ratio of the brightness of the white image to the black image is obtained in the liquid crystal panel 10 while the phase difference compensation plate 60 rotates by a minute angle. When the ratio reaches the maximum value, it can be considered that the phase difference compensation plate 60 is adjusted to a point where the phase difference of the liquid crystal panel 10 is optimally compensated. Therefore, the inspection unit 80 outputs the maximum value of the ratio as the contrast (ratio) of the liquid crystal panel 10.
Although the phase difference of the liquid crystal panel 10 varies from one individual to another, it is almost limited to a certain range. Therefore, it is not necessary to rotate the phase difference compensator 60 by knowing 360 degrees all around. For this reason, the time required for the inspection is short.

According to the first embodiment, the diffused light emitted from the light source 110 is collected by the incident side condensing lens 32 and irradiated to a part of the liquid crystal panel 10. The reflected light of the liquid crystal panel 10 becomes diffused light again, but is condensed by the output side condensing lens 34 and guided to the light receiving unit 120. Therefore, it is not necessary to use a screen for inspection, and the installation location is limited. Hateful. For this reason, it is possible to inspect in a space-saving manner.
Further, in contrast inspection, which is the ratio of white to black, ambient light at the time of detecting black can be a major factor in error, but in the present embodiment, the light receiving unit 120 includes the liquid crystal panel 10. Since the reflected light is collected and incident, it is not easily affected by stray light. For this reason, it is possible to improve the contrast inspection accuracy particularly for the reflective liquid crystal panel 10 capable of displaying a high contrast as in the present embodiment.
Since the condensed light is irradiated not on the entire surface of the liquid crystal panel 10 but on a part thereof, a light flux equivalent to that of a halogen lamp or a xenon lamp can be incident on the liquid crystal panel 10 even if an LED having a weak output is used as the light source 110. it can. For this reason, the liquid crystal panel 10 before being incorporated into the projector can be subjected to contrast inspection at a low cost and with low power consumption and with the same luminous flux as when incorporated.
Further, in the present embodiment, the light beam irradiated on the liquid crystal panel 10 and the light beam reaching the sensor 122 are the same. For this reason, since the illuminance detected by the sensor 122, that is, the amount of light flux per unit area is equal to the illuminance of light emitted from the liquid crystal panel 10, the performance of the liquid crystal panel 10 can also be more accurately inspected. become.

Next, a second embodiment of the present invention will be described.
In the second embodiment, the transmissive liquid crystal panel 10 is an inspection target. The configuration of the transmissive liquid crystal panel 10 is almost the same as that of FIG. 2, but light incident from the upper side in FIG. 2 is modulated and emitted downward, so that the frame 14 emits in the same manner as the incident side. The side is also open.

FIG. 4 is a schematic diagram showing an optical system of a contrast inspection apparatus according to the second embodiment.
In the second embodiment, since the transmissive liquid crystal panel 10 is an inspection target, the output side polarizer 54, the output side condensing lens 34, and the light receiving unit 120 are coaxially aligned with the optical axis 30a and emitted from the back surface of the liquid crystal panel 10. The configuration is arranged on the side.

In the second embodiment as described above, when inspecting the contrast of the transmissive liquid crystal panel 10, as in the first embodiment, it is not necessary to use a screen and it is difficult to be affected by stray light. It can also be increased.
Further, the transmissive liquid crystal panel 10 before being incorporated into the projector can be subjected to contrast inspection at a low cost and with low power consumption and with the same luminous flux as when incorporated. Furthermore, if the light beam applied to the liquid crystal panel 10 and the light beam reaching the sensor 122 are the same, the performance of the liquid crystal panel 10 can be more accurately inspected.

The present invention is not limited to the first and second embodiments described above, and various applications and modifications are possible as follows.
For example, in the first and second embodiments, an LED is used as the light source 110, but the same type as the projector incorporating the liquid crystal panel 10 such as a halogen lamp or a xenon lamp, or an example other than the LED as a solid light source You may use the semiconductor laser which is. By using a halogen lamp, a xenon lamp, etc., it becomes possible to inspect with light having the same wavelength as the projector to be incorporated. Furthermore, in the present embodiment, since the light is condensed and incident on a part of the liquid crystal panel 10, the amount of light can be reduced even when a halogen lamp, a xenon lamp, or the like is used as the light source, thereby extending the life of the lamp. It is done. For this reason, the inspection cost can be reduced.

In the embodiment, the incident side polarizer 52 is disposed on the exit side of the incident side condensing lens 32, but may be on the incident side. Similarly, although the exit side polarizer 54 is disposed on the entrance side of the exit side condenser lens 34, it may be disposed on the exit side.
In the embodiment, a diaphragm different from the diaphragm 72 may be provided between the emission side condensing lens 34 and the light receiving unit 120 to freely adjust the light flux reaching the sensor 122.

DESCRIPTION OF SYMBOLS 1 ... Inspection apparatus, 10 ... Liquid crystal panel, 32 ... Incident side condensing lens, 34 ... Outlet side condensing lens, 40 ... Polarizing beam splitter, 52 ... Incident side polarizer, 54 ... Outgoing side polarizer, 60 ... Phase difference Compensation plate, 80 ... inspection unit, 110 ... light source, 120 ... light receiving unit.

Claims (5)

A light source;
An optical member that condenses the light emitted by the light source into a first light flux and irradiates a part of the liquid crystal panel, and condenses the emitted light from the liquid crystal panel into a second light flux and guides it to the light receiving unit. When,
An inspection unit for inspecting the contrast of the liquid crystal panel based on the second light flux guided to the light receiving unit;
A contrast inspection apparatus comprising: 2. The contrast inspection according to claim 1, wherein a ratio of the first light beam irradiated to a part of the liquid crystal panel and the second light beam guided to the light receiving unit is 1: 1. apparatus. The contrast inspection apparatus according to claim 1, wherein the light source is an LED. The liquid crystal panel is a reflective type,
As the optical member,
The contrast inspection apparatus according to claim 1, comprising an incident side polarizer, an incident side condensing lens, a polarizing beam splitter, a phase difference compensator, an exit side polarizer, and an exit side condensing lens. . The liquid crystal panel is a transmissive type,
As the optical member,
The contrast inspection apparatus according to claim 1, 2, or 3, further comprising an incident side polarizer, an incident side condensing lens, an exit side polarizer, and an exit side condensing lens.

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