JPH10197838A - Optical element superposition device - Google Patents

Abstract

(57) [Abstract] (With correction) [Problem] When bonding a driving substrate and a counter substrate,
Provided is a device for superposing an optical element, which can perform superposition quickly and accurately even if the distance between two alignment marks is large. SOLUTION: When an alternating current is applied to coils 127a and 127b, a vertical movement force acts on a lens holder 125, and when the optical lens 122 comes to a first position, the focal point of the microscope moves to the position on the counter substrate 11A side. Alignment mark A ₁
Fits. On the other hand, when it comes to the second position, the drive substrate 11B
Fit alignment mark B ₁ side. The images of the alignment marks A ₁ and B ₁ are output from the video camera 13 on a monitor as a first image and a second image. When the second image is output on the monitor, it is as if the alignment marks A ₁ and B ₁ formed on the two substrates 11A and 11B are simultaneously observed due to the afterimage phenomenon of the first image. Can be recognized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superposing apparatus for superposing two substrates constituting an optical device such as a liquid crystal display device on the basis of an alignment mark, and more particularly to an optical device having a large gap between the two substrates. The present invention relates to a device for superposing optical elements used for manufacturing elements.

[0002]

2. Description of the Related Art In recent years, with the spread of electronic equipment having a liquid crystal display device such as a liquid crystal projector, demands for higher performance of the liquid crystal display device have increased, and the liquid crystal display device has been improved in definition and brightness. Improvements have been made. In general, a liquid crystal display element used in this liquid crystal display device includes a matrix-shaped pixel portion and a TFT (Thin Film Tran- sition) for controlling pixels.
(a thin-film transistor, thin film transistor), and a counter substrate on which a color filter, a black matrix, and the like are formed. These substrates are superimposed (positioned) on the basis of the alignment mark, and then bonded and integrated.

FIG. 6 shows a schematic configuration at the time of assembling a conventional liquid crystal display element. That is, the drive substrate 11
The opposing substrate 110A is arranged in parallel with the opposing substrate 0B, and an alignment mark a is formed on the opposing substrate 110A and an alignment mark b is formed on the driving substrate 110B. Conventionally, the driving substrate 110B and the opposing substrate 110A
At the time of bonding, the alignment marks a and b were simultaneously observed with the microscope 120, and if they were misaligned, the driving substrate 110B was moved in a horizontal direction by a moving table (not shown) to perform the alignment. Here, a predetermined gap (cell gap) d is provided between the driving substrate 110B and the counter substrate 110A because it is necessary to seal the liquid crystal in a later step. When the size of the gap d is about several microns, both of the alignment marks a and b fall within the depth of focus of the microscope 120, so that they can be accurately overlapped without any problem in visibility. When the alignment of the two substrates 110A and 110B is completed,
Temporary fixing is performed at several locations on the outer peripheral portion of the liquid crystal display element 110 with an instant adhesive, or temporary setting is performed by curing an ultraviolet curable resin with an optical fiber light source. After performing the temporary fixing, the entire liquid crystal display element 110 is heated, and the liquid crystal display element 110 is heated.
The thermosetting resin for sealing is fully cured and bonded. In addition, a halogen lamp is used as a light source (not shown) for illuminating the alignment marks a and b, and the light source (not shown) for irradiating the ultraviolet-curable adhesive with ultraviolet light is as described above. A different light source from the halogen lamp is used.

[0004]

However, in such a conventional method, the driving substrate 110B and the opposing substrate 11 are not provided.
If the gap d between 0A and 0A is as large as several hundred microns, the two alignment marks do not fall within the depth of focus of the microscope, so that the two marks cannot be observed simultaneously with good visibility, and the overlay accuracy However, there was a problem that was reduced. Hereinafter, this point will be described.

That is, recently, the liquid crystal display element has tended to be employed not only in a direct-view type but also in a projection type display device which projects an image by transmitting light. As this type of projection display device, there is a display device for a projection television. By the way, when the liquid crystal display element is used in a projection display device as described above, it is necessary to increase the number of pixels (picture elements) of the liquid crystal display element in order to improve the magnification at the time of projection. This is because, if an attempt is made to improve the enlargement ratio without increasing the number of pixels, the screen becomes coarse and the display quality deteriorates. However, when the number of pixels of the liquid crystal display element is increased, the area occupied by portions other than the pixels becomes relatively large, and accordingly, the area of the black mask covering the region other than the pixels increases, which contributes to image display. The pixel area relatively decreases, and the aperture ratio of the liquid crystal display element decreases. When the aperture ratio decreases, the display surface of the liquid crystal display element becomes dark, and the image quality deteriorates. Such a drawback becomes a serious problem particularly in the case of an active matrix type liquid crystal display device. Japanese Patent Application Laid-Open No. Sho 60-165621-165624 proposes a technique for preventing such a decrease in image quality due to a decrease in the aperture ratio of a liquid crystal display element. In this prior art, a microlens array is formed on one substrate surface of a liquid crystal display element. This microlens array consists of a number of microlenses corresponding to each pixel of the liquid crystal display element, and in the prior art, light that was blocked by a black mask is condensed on the pixels by the microlenses, thereby brightening the display surface, This prevents the image quality from deteriorating. In a liquid crystal display device having such a microlens array, it is necessary to precisely position each pixel and each microlens.

However, when assembling a liquid crystal display device having such a microlens array by a method as shown in FIG. 6, there are the following problems.

(1) When performing the superposition, the gap between the driving substrate and the opposing substrate is increased by the microlens array to about several hundred microns. Therefore, it is impossible for a normal microscope to simultaneously focus on the alignment marks formed on each of the substrates, and accurate accurate alignment cannot be quickly performed. (2) To perform alignment with high accuracy, it is necessary to recognize the alignment mark with high contrast and high definition. For this purpose, it is usually necessary to use a microscope having a high aperture ratio. The depth becomes shallow, and it becomes impossible to recognize both alignment marks formed on each substrate at the same time. On the other hand, a microscope capable of simultaneously recognizing both at the same time is a microscope with a low aperture ratio at present, and cannot recognize the alignment mark with high contrast and high definition.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the purpose of superposing two substrates on each other.
An object of the present invention is to provide an optical element overlaying device that can quickly and accurately perform overlaying even if the distance between two alignment marks is large.

[0009]

According to the present invention, there is provided an apparatus for overlaying an optical element, comprising: a first substrate on which a first alignment mark is formed; The second substrate on which the second alignment mark is formed is maintained at a predetermined gap, and the first substrate and the second substrate are referenced with reference to the first alignment mark and the second alignment mark. The two substrates are superposed by relatively moving the first and second substrates, and a first position where the first alignment mark is in focus and a second position where the second alignment mark is in focus. An optical lens displaceable along the direction of the optical axis between the first position and the second position, and driving means for reciprocating the optical lens between the first position and the second position. First alignment tool Image forming means for individually forming a clear image of each of the mark and the second alignment mark, and taking in images of the first alignment mark and the second alignment mark formed by the clear image forming means , An image input unit for converting the image into an image signal, and a first alignment mark and a second alignment mark output from the image input unit.
Image display means for displaying one image.

According to another aspect of the present invention, there is provided a device for superimposing an optical element, wherein the first alignment mark is focused on a first alignment mark.
And an optical lens displaceable along the optical axis direction between the first alignment mark and the second alignment mark, the second alignment mark being focused on the second alignment mark. Sharp image forming means for individually forming clear images of the respective alignment marks, and an optical lens for selectively fixing an optical lens in the clear image forming means to a first position and a second position Moving means, image input means for taking in images of the first alignment mark and second alignment mark formed by the clear image forming means, and converting them into image signals, respectively; and output from the image input means. Image display means for displaying two images of the first alignment mark and the second alignment mark.

In the apparatus for superposing optical elements according to the present invention, the first alignment is performed by the reciprocating drive of the optical lens displaceable along the optical axis direction in the clear image forming means by the driving means automatically. The mark and the second alignment mark are selectively focused, and a clear image of each mark is formed. Images of the first alignment mark and the second alignment mark formed by the clear image forming unit are taken into the image input unit and converted into image signals. This image signal is output to the image display means, and these images are displayed clearly. Here, when the optical lens is reciprocated at a high speed, the first alignment mark and the second alignment mark can be recognized as if they were simultaneously observed due to the afterimage phenomenon of the image.

In another apparatus for superposing optical elements according to the present invention, the optical lens in the sharp image forming means is selectively manually moved to the first position and the second position via the optical lens moving means. Fixed.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention.
1 shows a schematic configuration of a superposition apparatus 10 according to the embodiment. Superposition apparatus 10 according to the present embodiment
Are alignment marks A ₁ , B formed on the opposing substrate 11A and the driving substrate 11B constituting the liquid crystal display element 11.
_1. A microscope 12 as a clear image forming means for forming an enlarged image of A ₂ and B _{2, and} an image formed by the microscope 12 are taken in and alignment marks A _{1 and} A ₂ on the counter substrate 11A side are taken. Is a first image signal, a video camera 13 as image input means for outputting alignment marks B ₁ , B ₂ on the drive board 11B side as a second image signal, and a display for simultaneously displaying image signals. A monitor 14 as a means, and an XY-Y as a substrate moving means for performing positioning with respect to the opposing substrate 11A by slightly moving the driving substrate 11B in the XY biaxial directions and the rotation direction (θ) in a horizontal plane. table 15. Note that the first image signal and the second image signal output from the video camera 13 are respectively captured by the video camera 13 in real time and displayed on the monitor 14.

A color filter, a black matrix, and the like are formed on the opposing substrate 11A, and a plurality of hemispherical microlenses 11a, for example, are integrally formed on the surface thereof. This micro lens 11a is attached to the opposite substrate 11A.
The reason why they are formed integrally with each other is as follows. That is, while it is necessary to increase the number of pixels in response to the demand for miniaturization and high definition of the liquid crystal display element, when the number of pixels is increased, the area occupied by portions other than the pixels becomes relatively large, As a result, the area of the black mask for covering these regions increases, the pixel area contributing to image display decreases, and the aperture ratio of the liquid crystal display element decreases. When the aperture ratio decreases, the display surface of the liquid crystal display element becomes dark, and the image quality deteriorates. In order to prevent the image quality from being deteriorated due to such a decrease in the aperture ratio, a microlens 11a is integrally formed on the counter substrate 11A side, and the light incident by the microlens 11a is placed in the pixel on the drive substrate 11B side. The light is focused. The microlenses 11a can be formed, for example, by selectively etching the base material (glass substrate) of the counter substrate 11A and embedding a transparent resin.

Cross-shaped alignment marks A ₁ and A ₂ , for example, shown in an enlarged manner in FIG. 2A are formed on both left and right sides of the counter substrate 11A. These alignment marks A ₁ and A ₂ are formed by evaporating, for example, Al (aluminum). A cover glass plate 11b for flattening a liquid crystal layer to be filled in a later step is attached to the surface of the microlens 11a formed on the counter substrate 11A. The thickness of the cover glass plate 11b depends on the refractive index of the microlens 11a and the opposing substrate 11A.
, The pixel pitch of the liquid crystal display element 11, and the like.

On the other hand, a pixel portion and a TFT (Thin Fil) for controlling pixels arranged in a matrix
m Transistor, thin film transistor) and the like, and square alignment marks B ₁ , B ₂ having a cross line 20 formed at the center as shown in FIG. Is formed by evaporating Al, for example.

These alignment marks A ₁ , B ₁ , A ₂ , B
The microscope 12 for observing ₂ is constituted by an infinite optical system, and is a microscope having a high aperture ratio that can be recognized with high contrast and high definition. In this embodiment, the internal optical lens is driven at high speed by a control device such as a VCM (Voice Coil Motor) at a frequency of several tens of Hz, preferably 30 Hz or more, so that the optical axis is caused by the afterimage phenomenon on the monitor 14. Alignment marks A ₁ ,
B ₁ , A ₂ , and B ₂ can be recognized as if they were aligned at the same time.

That is, as shown in FIG. 3, the microscope 12 has a plurality of, for example, four optical lenses 121 to 124 in a lens barrel 120, of which three optical lenses 12 to 124 are provided.
1, 123 and 124 are respectively fixed. The remaining optical lens 122 is held by a lens holder 125 formed of a magnetic material. This lens holder 1
25 is a linear motion guide 1 provided in the longitudinal direction of the lens barrel 120.
The optical lens 122 is moved up and down along with 26 by the following driving means, so that the optical lens 122 can reciprocate along the optical axis direction. The moving range of the optical lens 122 is the opposing substrate 11A, the driving substrate 11B, the micro lens 11a.
And the thickness of the cover glass plate 11b.

A coil 127a and a coil 127b connected in series with each other
Is wound. Coil 127a and Coil 127
In b, the winding directions are opposite to each other, and an alternating current flows under the control of a control device (not shown). Further, a coil 127 is provided on the inner wall surface of the lens barrel 120.
A magnet 128a (for example, S-pole) and a magnet 128b (for example, N-pole) having a ring shape and different polarities are provided at positions facing the coil 127a and the coil 127b, respectively, and form a magnetic circuit together with the coil 127a and the coil 127b. ing. Further, a position detection sensor 129 is provided adjacent to a lower portion of the magnet 128b. The optical lens 122 is detected by the position detection sensor 129, and the moving direction, the moving amount, and the driving speed of the lens holder 125 are managed by PID control or the like according to the detection state. Here, when an alternating current is applied to the coils 127a and 127b, a vertical force acts on the lens holder 125 according to Fleming's left-hand rule, and the optical lens 122 moves at high speed along the optical axis direction in FIG. It reciprocates between a first position indicated by a dotted line and a second position indicated by a two-dot chain line. The above magnetic circuit (coils 127a and 127b and magnets 128a and 128b)
The position detection sensor 129 and a control device (not shown) constitute a driving unit of the present invention.

In the liquid crystal display element 11 used in the present embodiment, the alignment marks A ₁ , A on the counter substrate 11A side.
₂ and the gap D between the alignment mark B _1, B ₂ of the driving substrate 11B side, as compared with the conventional microlens 11a and the thickness of the cover glass plate 11b (several hundred microns)
Just get bigger. If the two sets of marks are separated in the height direction as described above, the two alignment marks do not fall within the depth of focus of the microscope as described above, and the two marks cannot be observed simultaneously with good visibility. However, the overlay accuracy is reduced. Superposition apparatus 10 according to the present embodiment
Is provided with an optical lens 122 that can move at high speed along the optical axis, and the alignment marks A ₁ ,
It focuses quickly on B ₁ , A ₂ and B ₂ .

Hereinafter, the operation of the superposition apparatus 10 will be described with reference to FIGS. That is, when an alternating current is applied to the coils 127a and 127b by a control device (not shown), a vertical force acts on the lens holder 125 according to Fleming's left-hand rule, and the optical lens 122 operates at a high speed (for example, 30 Hz). It reciprocates along a direction between a first position shown by a solid line in FIG. 3 and a second position shown by a two-dot chain line. When the optical lens 122 comes to the first position, the focal point of the microscope 12 is
Fits the alignment marks A ₁ side, a clear image as shown in FIG. 2 (a) is formed. Alignment marks A ₁ of the image at this time is taken into the video camera 13 in real time, and is output as a first image from the video camera 13 on the monitor 14.

The focus of the microscope 12 when the optical lens 122 has come to a second position fit alignment mark B ₁ of the driving substrate 11B side, a clear image as shown in FIG. 2 (b) is formed. Image of the alignment mark B ₁ represents incorporated in the video camera 13 in real time, is output as the second image from the video camera 13 on the monitor 14. Here, when the second image is output on the monitor 14, the operator operates the alignment mark A formed on the two substrates 11A and 11B by the afterimage phenomenon of the first image.
_1, B ₁ and though it is possible to recognize as if it is observed at the same time.

[0024] In this state, the alignment mark B of the alignment marks A ₁ and the driving substrate 11B side of the counter substrate 11A side
_{When 1} is shifted from each other as shown by a two-dot chain line in FIG. 2C, for example, the XY-θ table 15 is driven so that the two marks overlap. In the present embodiment, the drive substrate 11B is moved. Note that the positioning is similarly performed for the positioning marks A ₂ and B ₂ . When the positions of the two alignment marks A ₁ , B ₁ , A ₂ , and B ₂ match on the monitor 14, then,
For example, while applying a predetermined pressure between the opposing substrate 11A and the driving substrate 11B by a pressing device (not shown),
An ultraviolet-curable resin previously applied to a position (peripheral portion) (not shown) of one of the substrates is temporarily cured by an optical fiber light source. Thereafter, the entirety of the opposing substrate 11A and the driving substrate 11B is heated, and the thermosetting resin is fully cured to be bonded. Thereby, the driving substrate 11B and the opposing substrate 1
The step of laminating (bonding) with 1A is completed. Thereafter, the drive substrate 11B is driven by a liquid crystal injection device (not shown).
Liquid crystal is injected into a space between the substrate and the counter substrate 11A.

As described above, in the superposing apparatus 10 according to the present embodiment, when observing a mark with the microscope 12, the optical lens 122 is driven at a high speed to drive the drive substrate 11
A and the opposing substrate 11B are individually and quickly focused, and the alignment marks A ₁ , B ₁ and the alignment marks A ₂ , B ₂ are respectively monitored substantially simultaneously.
Displayed above. That is, in the present embodiment, even when the driving substrate 11A and the opposing substrate 11B are largely separated in the height direction, the alignment marks A ₁ and B _{1 are used.}
In addition, the focus can be quickly focused on the alignment marks A ₂ and B ₂ , respectively.
1B can be accurately superimposed. In addition, since the alignment can be performed using the raw information of each mark, even if the position of the base mark is shifted for some reason, quick and accurate correspondence can be taken, and the alignment accuracy can be further improved. improves. Further, since a microscope having a high aperture ratio can be used as the microscope 12, each alignment mark can be recognized with high contrast and high definition.

FIGS. 4 and 5 show a schematic configuration of a superposition apparatus according to a second embodiment of the present invention.
In the present embodiment, the optical lens 122 is manually moved. The same components as those in FIGS. 1, 2, and 3 are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, the optical lens 122 in the microscope 12 is held by a lens holder 130 as shown in FIG. The lens holder 130 can be moved up and down within a certain range in the optical axis direction of the lens barrel 120. On one side surface of the lens holder 130, a lever insertion hole 130a for inserting the lever 131 and a screw hole 130b for screwing the fixing screw 132 are formed. The lens barrel 120 has a lever guide hole 120a corresponding to the lever insertion hole 130a and a screw guide hole 120b corresponding to the screw hole 130b. The upper and lower widths of the lever guide hole 120a and the screw guide hole 120b are set to lengths according to the moving range of the optical lens 122 (the range from the first position to the second position).

Further, in this embodiment, as shown in FIG. 4, an image memory 41 for storing the image signal from the video camera 13 shown in the first embodiment, and an image memory 41 for storing the image signal. An image synthesizing circuit 42 for synthesizing the image signal and the image signal output from the video camera 13 is provided. The configuration other than the image memory 41 and the image composition circuit 42 is the same as that of the first embodiment.

The operation of the superposition device 40 will be described below with reference to FIGS. 2, 4 and 5. That is, first, the lens holder 130 is fixed at the uppermost position with the fixing screw 132, and the optical lens 122 is positioned at the first position indicated by the solid line. The focus of this time the microscope 12 is fit with the alignment marks A ₁ of the counter substrate 11A side, a clear image as shown in FIG. 2 (a) is formed.
Image of the alignment mark A ₁ is received by the video camera 13, it is outputted from the video camera 13 as a first image signal. The first image signal output from the video camera 13 is temporarily stored in the image memory 41. Next, as the focal point of the microscope 12 is aligned with the alignment mark B ₁ of the driving substrate 11B side, and insert the lever 131 to the lever insertion hole 130a of the lens holder 130, by fixing by a fixing screw 132 pressed downward Optical lens 1
22 is positioned at a second position indicated by a two-dot chain line.
At this second position, a clear image as shown in FIG. 2B is formed as described above. Image of the alignment mark B ₁ represents incorporated in the video camera 13, is outputted from the video camera 13 as the second image signal.
The second image signal output from the video camera 13 is input to one input terminal of the image synthesis circuit 42. At the same time, the other input terminal of the image synthesizing circuit 42 receives the first image signal once stored in the image memory 41. The image synthesizing circuit 42 alternately selects the first image signal and the second image signal and outputs them to the monitor 14. Here, each of the first image signal and the second image signal has information of one field, and one frame is composed of these two signals. Thus, two images for the alignment marks A and B are displayed at the same time. When the XY-θ table 15 is moved for correction when the alignment marks A and B are shifted, the shape of the alignment marks A ₁ and B ₁ is changed at predetermined time intervals by the video camera. 13 to the image memory 41. Therefore, the latest shape of the alignment marks A ₁ and B ₁ is always stored in the image memory 41, and the monitor 14 can know the alignment status in real time. Note that the positioning is similarly performed for the positioning marks A ₂ and B ₂ . Alignment marks A ₁ , B ₁ , A ₂ ,
Step after the position of the B ₂ match is the same as in the first embodiment.

As described above, in the superposing apparatus 40 according to the present embodiment, when observing the mark with the microscope 12, the optical lens 122 is moved up and down together with the lens holder 130 in the optical axis direction to move the drive substrate 11A and the opposing substrate. 11
B and the image on the counter substrate 11A side (the alignment mark A
₁ , A ₂ ) are once fetched into the image memory 41, and then displayed on the monitor 14 at the same time as the focused image (positioning marks B ₁ , B ₂ ) on the drive board 11B side. Therefore, the images of the alignment marks A ₁ , B ₁ , A ₂ , and B ₂ displayed on the monitor 14 are clear. Therefore, similarly to the first embodiment, also in the present embodiment, the drive substrate 11A and the opposing substrate 1
1B, even if it is greatly separated in the height direction,
The driving substrate 11A and the opposing substrate 11B can be accurately positioned. Also, by improving the accuracy of the superposition, it is possible to sufficiently bring out the light condensing effect on the pixels on the drive substrate 11B side by the microlenses 11a provided on the counter substrate 11A side, and to achieve high luminance. be able to.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, and can be variously modified. For example, in the above embodiment, the image (first alignment marks A ₁ , A ₂ ) on the opposing substrate 11A side is taken into the video camera 13 first. The two alignment marks B ₁ and B ₂ ) may be taken into the video camera 13 first, and in this case, the opposite substrate 11A may be moved for superposition. Also,
In the second embodiment, the images of the opposing substrate 11A and the driving substrate 11B output from the video camera 13 are alternately selected by the image synthesizing circuit 42 and displayed on the monitor 14 as they are. May be displayed after the arithmetic processing is performed.

The shape, position, number, etc., of each alignment mark are not limited to those of the above-described embodiment, but may be arbitrary. Furthermore, in the above-described embodiment, the liquid crystal display element 11 including the counter substrate 11A and the driving substrate 11B integrated with the microlens is described as the object to be superimposed. The present invention can be generally applied to a device including two substrates separated from each other.

[0032]

As described above, according to the optical element superimposing apparatus according to the first and fourth aspects, the optical lens displaceable along the optical axis direction and the optical lens for reciprocatingly driving the optical lens. The drive means automatically drives the optical lens back and forth in the optical axis direction, and the image display means displays the two images of the first alignment mark and the second alignment mark individually. Therefore, it is possible to quickly focus on the alignment marks on the first substrate and the second substrate, respectively.
Even if the marks on the two substrates are far apart from each other, it is possible to perform the superposition quickly and accurately.

Further, according to the optical element overlapping device according to the second and third aspects, the optical lens can be manually moved in the optical axis direction, so that the first substrate and the second substrate can be similarly moved. The focus can be individually adjusted on each of the alignment marks on the substrates, and even if the positions of the marks on the two substrates are far apart from each other, it is possible to perform the overlay with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a superposition apparatus according to a first embodiment of the present invention.

FIG. 2 is a view for explaining a display state of two alignment marks on a monitor by the superposition apparatus of FIG. 1;

FIG. 3 is a cross-sectional view illustrating a specific configuration inside a microscope of the superposing apparatus in FIG.

FIG. 4 is a block diagram illustrating a schematic configuration of a superposition apparatus according to a second embodiment of the present invention.

5 is a cross-sectional view illustrating a configuration of a main part of the superposing apparatus in FIG.

FIG. 6 is a view for explaining a method of superposing a driving substrate and a counter substrate in a conventional liquid crystal display element.

[Explanation of symbols]

11: liquid crystal display element, 11A: counter substrate, 11B: drive substrate, 11a: micro lens, 11b: cover glass plate, 12: microscope, 13: video camera, 14: monitor, 15: XY-θ table, 120 ... Barrel, 12
1, 122, 123, 124: optical lens, 125: lens holder, 126: linear guide, 127a, 127b
... Coil, 128a, 128b ... Magnet, 129 ... Position detection sensor, 41 ... Image memory, 42 ... Image synthesis circuit, A
_{1, B 1, A 2,} B 2 ... alignment mark

Claims (4)

[Claims] A first substrate on which a first alignment mark is formed; and a second substrate on which a second alignment mark serving as a reference for overlaying the first substrate is formed. While maintaining a predetermined gap, the first substrate and the second substrate are relatively moved with respect to the first alignment mark and the second alignment mark, thereby obtaining 2
In a superposing apparatus for superposing two substrates, a first position in focus on the first alignment mark and a second position in focus on the second alignment mark
An optical lens displaceable along the optical axis direction between the first position and the second position, and driving means for reciprocating the optical lens between a first position and a second position. First alignment mark and second alignment mark
A clear image forming means for individually forming a clear image of each of the positioning marks, and images of the first positioning mark and the second positioning mark formed by the clear image forming means are taken in, and the respective image signals are read. An optical system comprising: an image input unit for converting the image into an image; and an image display unit for displaying two images of the first alignment mark and the second alignment mark output from the image input unit. A device for superposing elements. 2. A first substrate on which a first alignment mark is formed, and a second substrate on which a second alignment mark serving as a reference for superposition on the first substrate is formed. While maintaining a predetermined gap, the first substrate and the second substrate are relatively moved with respect to the first alignment mark and the second alignment mark, thereby obtaining 2
In a superposing apparatus for superposing two substrates, a first position in focus on the first alignment mark and a second position in focus on the second alignment mark
A clear image forming means for individually forming clear images of the first alignment mark and the second alignment mark by using the optical lens displaceable along the optical axis direction between the first alignment mark and the second alignment mark. An optical lens moving means for selectively fixing an optical lens in the clear image forming means at a first position and a second position; and a first alignment mark formed by the clear image forming means. Image input means for taking in an image of the second alignment mark and converting the image into an image signal, and two images of the first alignment mark and the second alignment mark output from the image input means And an image display means for displaying an image. 3. An image storage means for temporarily storing an image signal for an alignment mark output first among image signals output from the image input means, and stored in the image storage means. Image synthesizing means for synthesizing the obtained image signal and an image signal for an alignment mark to be output later from the image input means, wherein the image display means comprises a first alignment synthesized by the image synthesizing means. 3. The apparatus according to claim 2, wherein two images of the mark and the second alignment mark are displayed simultaneously. 4. A first substrate to be superimposed is a driving substrate for a liquid crystal display element having a pixel portion in which a plurality of pixels are arranged in a matrix, while the second substrate is a driving substrate for the liquid crystal display device. A microlens for condensing light is formed on the pixel portion, and a transparent plate for flattening a liquid crystal layer is provided between the microlens and the driving substrate. The gap between the first alignment mark formed on the side of the substrate and the second alignment mark formed on the side of the driving substrate is determined by the thickness of the microlens, the thickness of the transparent plate, and the filling of the liquid crystal. 2. The apparatus according to claim 1, wherein the size is set to include the height of the space.