JP2013044782A - Optical element, electro-optical device, projection type video device and manufacturing method of optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element that can be identified when used in products and has an identification mark that is not erased or blurred.SOLUTION: An optical element comprises: a translucent substrate 101; a recognition mark M provided in a peripheral region E outside an optical region L of the translucent substrate 101; and an anti-reflection film AR serving as an optical functional film provided on a main surface of the translucent substrate 101 so as to cover the recognition mark M. The recognition mark M has been printed by an ink-jet system on the main surface of the translucent substrate 101. Since the recognition mark M is provided in the peripheral region E outside the optical region of the translucent substrate 101, original function as a dust-proof glass is not inhibited. Since the recognition mark M is directly formed by the ink-jet system on the translucent substrate 101, ink-jet ink does not blur and the recognition mark M can be clearly recognized.

Description

  The present invention relates to an optical element, an electro-optical device including the optical element, a projection-type image device including the electro-optical device, and a method for manufacturing the optical element.

An electro-optical device is incorporated in an electronic apparatus, for example, a projection type video apparatus. As this electro-optical device, a transparent substrate and a liquid crystal light valve are bonded using an acrylic ultraviolet curing adhesive, and the transparent substrate is placed on the glass substrate and the liquid crystal light valve side surface of the glass substrate. There is a conventional example of a two-layer structure in which a light-shielding film is provided, and the light-shielding film is formed by laminating a reflective film that reflects incident light from the outside and an absorption layer that absorbs return light from the liquid crystal light valve side. Yes (Patent Document 1).
In the conventional example shown in Patent Document 1, the light shielding film is configured by stacking a chromium film as a reflection film and a chromium oxide film as an absorption layer. Here, the incident light is reflected on the surface of the reflective film made of a chromium film, and the return light from the liquid crystal light valve is absorbed by the absorption film made of a chromium oxide film to suppress reflection. As described above, the light-shielding film is required to have a function of efficiently reflecting incident light to suppress the transmittance and suppressing reflection of return light from the liquid crystal light valve.

Further, as an electro-optical device, there is a conventional example in which an antireflection film is formed on a light incident surface of a dustproof glass substrate, and a light incident side dustproof glass and a counter substrate of a transmissive liquid crystal panel are bonded together with an adhesive layer (Patent Document 2).
In the conventional example of Patent Document 2, reflection at the interface of the adhesive layer is suppressed by making the refractive index of the adhesive layer close to the refractive index of the light incident side dust-proof glass and the refractive index of the counter substrate. The reflective film is formed on the outer periphery of the light incident surface of the dust-proof glass substrate. As the reflection film, a metal film such as chromium, aluminum, silver or the like is used. An antireflection film is formed on the light incident surface including the reflection film. The rectangular annular pattern of the reflection film of the light incident side dust-proof glass is formed so as to be aligned vertically and horizontally with a cutting margin.

By the way, in recent years, in order to manage the quality of a transparent substrate as an optical element and the quality of an electro-optical device including the transparent substrate so that it can be traced using a lot number or the like, the surface of the optical element may be marked. is there.
In optical elements, it is necessary to mark outside the optical area so as not to affect the optical characteristics, but the surface of the reflective film (chromium, silver, etc.) or antireflection film (dielectric multilayer film) is laser If the marking is formed by deleting in a letter-like manner, the light incident from the deleted region becomes stray light, which causes a problem that the amount of light transmitted through the liquid crystal panel is reduced.

Therefore, it is conceivable to use an ink jet method as a method of marking.
As a conventional example of printing using an ink jet method, for example, there is one that performs ink marking on the surface of a resin tape covering a cable of an optical fiber cable using an ink jet (Patent Document 3).
Furthermore, there is a conventional example in which a protective film is provided on one side of an optical film made of a polarizing film or the like via an adhesive layer, and ink information for identification is formed on the surface of the protective film by an inkjet method (Patent Document 4).

  Moreover, in the polarizing plate with a protective film in which the protective film is detachably pasted on the surface of the polarizing plate, there is a conventional example in which the surface of the protective film is marked with ink jet ink (Patent Document 5). In the conventional example of Patent Document 5, marking with ink jet ink is not particularly limited, and is performed by using one type of letters, numbers, symbols, figures, pictures, or the like, or a combination of two or more types. The marking position is also set appropriately. A bar code can be attached by marking, and a polarizing plate with a protective film can be managed as a bar code, so that shipping number accumulation, delivery quantity, quality information, product number code, etc. can be collectively managed.

Further, in an optical low-pass filter in which an adhesive layer is provided between the first crystal plate and the retardation film, and an adhesive layer is provided between the retardation film and the second crystal plate, the surface of the adhesive layer is optically effective. There is a conventional example in which a mark is formed by an inkjet printer outside an area (Patent Document 6).
Further, there is a conventional example in which a dustproof substrate is attached to a liquid crystal panel, and a mark is formed in a portion other than the effective area of the liquid crystal panel of the dustproof substrate (Patent Document 7). In the conventional example of Patent Document 7, a dustproof substrate is attached to the TFT substrate side of the liquid crystal panel with an adhesive, and the surface of the dustproof substrate opposite to the surface facing the TFT substrate is, for example, an inkjet or laser. A mark is formed by a method such as a metal foil transfer method using a glass or a glass direct marking using a laser.

JP 2008-233733 A JP 2008-170946 A JP-A-1-150105 JP 2000-32422 A JP 2003-014934 A JP 2007-072268 A JP 2009-047880 A

In the conventional examples shown in Patent Documents 1 and 2, there is no mention regarding attaching an identification mark indicating the product number of the optical element in addition to the optical region of the optical element.
In the conventional example shown by patent document 3, since the marking is carried out by the inkjet on the surface of the resin tape, marking will be exposed and there exists a subject that a mark peels off at the time of product use.
In the conventional example shown in Patent Document 4, since the identification ink is formed on the surface of the protective film, the identification ink is exposed and there is a problem that the ink is peeled off. Moreover, the optical material cannot be identified after the protective film is peeled off in order to actually use the optical material.

In the conventional example shown by patent document 5, since the marking is given to the surface of the protective film with the inkjet ink similarly to the conventional example of patent document 4, the peeling accompanying the exposure of the marking or the protective film After peeling off, there is a problem that the polarizing plate cannot be identified.
In the conventional example shown in Patent Document 6, since the mark is provided on the surface of the adhesive layer, depending on the relationship between the ink jet and the material constituting the adhesive layer, the mark may bleed and be accurately identified. There is a problem that cannot be done.
In the conventional example shown in the cited document 7, since the mark is exposed and formed on the surface of the dustproof substrate, the mark may be rubbed or peeled off.

  An object of the present invention is to solve the above-described problems, and is an optical element, an electro-optical device, which can be identified even when the product is used, and the identification mark does not disappear or blur. It is an object of the present invention to provide a projection type video apparatus and a method for manufacturing an optical element.

[Application Example 1]
The optical element according to this application example includes a translucent substrate, a recognition mark provided in a peripheral region outside the optical region of the translucent substrate, and the translucent substrate so as to cover the recognition mark. An optical element including an optical functional film provided on a main surface, wherein the recognition mark is printed on the main surface of the translucent substrate by an ink jet method.
In this application example of this configuration, since the recognition mark is provided in the peripheral region outside the optical region of the translucent substrate, the recognition mark can be recognized without hindering the original function as an optical element. it can. In addition, since the recognition mark is directly formed on the light-transmitting substrate by the ink jet method, the recognition mark can be clearly recognized without ink bleeding compared to the case where it is formed on the adhesive layer. . In the ink jet method, the recognition mark can be made easier to see by setting the color of the ink used to be easier to see than the optical function film. Furthermore, since the recognition mark is covered with the optical functional film, the recognition mark can be used when the product is used, and the recognition mark is not rubbed or peeled off. And the film | membrane which covers a recognition mark is an optical function film indispensable with an optical element, and it is not required to coat | cover another. Therefore, since the formation of the recognition mark can be incorporated in the conventional optical element manufacturing procedure, the manufacturing cost of the optical element can be suppressed.
Here, the recognition mark is information about the product such as the model number of the optical element or the electro-optical device, and other information, and is displayed by numbers, characters, symbols, and the like. The optical region is a region on the main surface that is effectively used as an optical element.

[Application Example 2]
In the optical element according to this application example, the optical function film is an antireflection film.
In this application example having this configuration, since the recognition mark is provided between the antireflection film and the translucent substrate, the function of the antireflection film itself is not impaired.

[Application Example 3]
In the optical element according to this application example, the optical functional film is a light-shielding film provided in a peripheral region outside the optical region of the light-transmitting substrate, and the light-shielding film is incident on the light-transmitting substrate. It has a reflection layer that reflects light and an absorption layer that absorbs the light, and the reflection layer and the absorption layer are sequentially stacked on the surface of the translucent substrate.
In this application example having this configuration, even if light is transmitted through the translucent substrate, the light is reflected by the reflective layer, and the light incident on the absorption layer after passing through the optical region of the translucent substrate is absorbed by the absorption layer. Absorbed in. Therefore, even if there is a recognition mark, the function of the light shielding film itself is not impaired.

[Application Example 4]
In the optical element according to this application example, the recognition mark is provided between the translucent substrate and the reflective layer.
In this application example having this configuration, since the recognition mark is provided between the translucent substrate and the reflective layer, the recognition mark provided directly on the translucent substrate is easily recognized through the translucent substrate.

[Application Example 5]
In the optical element according to this application example, the recognition mark is provided between the reflective layer and the absorbing layer.
In this application example having this configuration, since the recognition mark is provided between the reflection layer and the absorption layer, the recognition mark can be recognized from the back side of the optical element through the absorption layer.

[Application Example 6]
An electro-optical device according to this application example includes the optical element having the above-described configuration and a liquid crystal panel, and a main surface of the translucent substrate on which the recognition mark is not provided is opposed to the liquid crystal panel. It is characterized by that.
In this application example having this configuration, the position of the liquid crystal panel is suitable in the optical element in which the antireflection film is used as the optical function film.

[Application Example 7]
An electro-optical device according to this application example includes the above-described optical element and a liquid crystal panel, and a main surface of the translucent substrate on which the light-shielding film is provided is opposed to the liquid crystal panel. It is characterized by being.
In this application example having this configuration, the position of the liquid crystal panel is suitable in the optical element in which the light shielding film is used as the optical function film.

[Application Example 8]
A projection type video apparatus according to this application example includes a light source, an electro-optical device that modulates light from the light source according to image information, and a projection optical device that projects light modulated by the electro-optical device. The electro-optical device is the above-described electro-optical device.
In this application example having this configuration, it is possible to provide a projection type video apparatus capable of producing the above-described effects.

[Application Example 9]
In the manufacturing method of the optical element according to this application example, the recognition mark is printed by an inkjet method on the main surface of the peripheral region outside the optical region of the translucent substrate, and the optical function film is formed so as to cover the recognition mark. It is provided on the main surface of the translucent substrate.
In this application example having this configuration, an optical element capable of producing the above-described effects can be easily manufactured.

1 is a cross-sectional view of an optical element according to a first embodiment of the present invention. The top view of the optical element concerning a 1st embodiment. FIGS. 3A to 3D are schematic views illustrating a method for manufacturing an optical element according to the first embodiment. FIG. 6 is a cross-sectional view of an electro-optical device according to a second embodiment of the invention. FIG. 6 is a plan view of an electro-optical device according to a second embodiment. FIGS. 4A to 4C are schematic views illustrating a method for manufacturing the electro-optical device. FIGS. (D) and (E) are schematic diagrams for explaining a method of manufacturing the electro-optical device. FIG. 9 is a cross-sectional view illustrating an electro-optical device according to a modification of the second embodiment. FIG. 6 is a cross-sectional view of an electro-optical device according to a third embodiment of the invention. FIG. 9 is a plan view of an electro-optical device according to a third embodiment. FIG. 9 is a cross-sectional view of an electro-optical device according to a fourth embodiment of the invention. FIG. 10 is a rear view of an electro-optical device according to a fourth embodiment. FIG. 10 is a cross-sectional view of an electro-optical device according to a fifth embodiment of the invention. FIG. 3 is a plan view of a side from which light of an optical element constituting the electro-optical device is emitted. The expanded sectional view of the principal part of an electro-optical apparatus. FIGS. 6A to 6C are perspective views illustrating a method for manufacturing an electro-optical device. FIGS. (D) and (E) are perspective views illustrating a method for manufacturing an electro-optical device. FIG. 6 is an enlarged cross-sectional view illustrating a main part of a modified example of the electro-optical device. The expanded sectional view which shows the principal part of the different modification of an electro-optical apparatus. Schematic which shows the projection type video apparatus which concerns on 6th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, in description of each embodiment, the same component is attached | subjected with the same code | symbol, and description is abbreviate | omitted or simplified.
1st Embodiment is described based on FIGS. 1-3.
FIG. 1 shows a cross section of the optical element 100 of the first embodiment, and FIG. 2 shows a plane of the optical element 100. The optical element 100 according to the present embodiment is used in a projection video apparatus, a digital camera, and other electronic devices.
1 and 2, an optical element 100 is a dust-proof glass including a translucent substrate 101 and an antireflection film AR as an optical functional film provided on the surface of the translucent substrate 101. An optical region L is provided in the central portion of the main surface. In FIG. 1, the antireflection film AR is shown to have the same thickness as the translucent substrate 101, but this is for easy understanding of the configuration of the antireflection film AR. The thickness of the antireflection film AR is smaller (thinner) than the thickness of the translucent substrate 101.

The light-transmitting substrate 101 is a substrate formed of a material such as quartz, alkali-free glass, crystal, sapphire, lithium niobate (LiNbO ₃ : LN), lithium tantalate (LiTaO ₃ : LT), for example. The translucent substrate 101 is formed to have a rectangular outer periphery in a plan view in which the horizontal and vertical dimensions are predetermined dimensions, for example, the vertical dimension is 10 mm to 30 mm and the horizontal dimension is 13 mm to 40 mm.
The optical region L has a rectangular outer periphery in plan view, and the position of each side is set with an appropriate dimension from each side of the translucent substrate 101, for example, 2 mm.
The antireflection film AR includes a low refractive layer and a high refractive layer, for example, a low refractive index silicon oxide (SiO ₂ ) low refractive layer, and a high refractive index titanium oxide (TiO ₂ ) or tantalum oxide (Ta ₂ O _5). ) High refractive layers are alternately stacked.

A recognition mark M is formed on a peripheral portion E which is a main surface of the translucent substrate 101 where the antireflection film AR is provided and is out of the optical region L.
In FIG. 2, the recognition mark M is displayed as a symbol “ABC”. The recognition mark M can be recognized through the antireflection film AR. In the present embodiment, in addition to the characters “ABC”, other alphabets, Japanese characters, characters for constituting other languages, numbers, symbols, figures, barcodes, and the like can be identified. If there is, the kind is not limited. In the present embodiment, the recognition mark M is displayed in a large size so that it can be easily read. However, it may be of a size that can be read by the naked eye or a machine. In FIG. 2, the position where the recognition mark M is displayed is the lower side of the planar rectangular optical element 100, but may be a corner of the optical element 100.

FIG. 3 schematically shows a method for manufacturing the optical element 100 according to the first embodiment.
In FIG. 3A, first, a large substrate 101A is prepared. By dividing the large-sized substrate 101A into a plurality of, in the drawing, nine pieces in the drawing, one substrate of the translucent substrate 101 shown in FIGS. 1 and 2 is obtained.
As shown in FIG. 3B, a recognition mark M “ABC” is printed by an inkjet method at a position corresponding to each light-transmitting substrate 101 of the large-sized substrate 101A.
Here, the ink jet system is generally filled with ink in a pressure chamber provided with a fine nozzle opening having a diameter of 10 to 100 μm and a pressure generating element, and the pressure generating element is electronically controlled to control the inside of the pressure chamber. The ink is pressurized, and the ink is ejected as fine droplets from the nozzle opening with that pressure. Depending on the type of pressure generating element, there are various systems such as a piezo system using a piezoelectric vibrator using a piezo element, and an ink jet system that uses a heating element to generate bubbles by heating ink and using the pressure. In the present embodiment, any inkjet method can be used. The ink is made of a material that does not repel when applied to the translucent substrate 101.
Thereafter, as shown in FIG. 3C, an antireflection film ARA is vapor-deposited on one surface of the large-sized substrate 101A by a method similar to the conventional method. The antireflection film ARA is formed after the recognition mark M printed on the large substrate 101A is dried. In FIG. 3C, the antireflection film ARA is illustrated in a film shape, but this schematically shows that the antireflection film ARA is provided on the large-sized substrate 101A. The prevention film ARA does not mean that the film is formed on the large substrate 101A.
Further, as shown in FIG. 3D, a large substrate 101A is divided into a plurality of parts by a dicing apparatus or other apparatus, and in this embodiment, it is divided into nine parts, and one optical element 100 is manufactured.

Therefore, in the first embodiment, the following operational effects can be achieved.
(1) A translucent substrate 101 on which a recognition mark M is printed by an inkjet method in a peripheral region E that is out of the optical region L, and an optical functional film provided so as to cover the recognition mark M on the translucent substrate 101 The anti-reflection film AR is provided, and the dust-proof glass optical element 100 is configured. Since the recognition mark M is provided in the peripheral area E outside the optical area L of the translucent substrate 101, the recognition mark M can be recognized without impairing the original function as dust-proof glass. In addition, since the recognition mark M is directly formed on the translucent substrate 101 by the ink jet method, the ink for ink jet does not bleed and the recognition mark M can be clearly recognized. Since the recognition mark M is covered with the antireflection film AR, the recognition mark M can be used when the product is used, and the recognition mark M is not rubbed or peeled off. And since the film | membrane which covers the recognition mark M is the antireflection film AR, since it is not necessary to coat | cover separately, the manufacturing cost of an optical element can be held down.

(2) Since the recognition mark M is provided on the main surface of the translucent substrate 101 on the side where the antireflection film AR is provided, and the antireflection film AR is provided so as to cover the recognition mark M, the antireflection film AR The function is not impaired.
(3) In a large-sized substrate 101A in which a plurality of optical regions L are formed on a plane, a plurality of recognition marks M are printed by an ink jet method on a region outside the optical region L, and reflected so as to cover these recognition marks M Since the prevention film ARA is provided on the large substrate 101A and then cut into a predetermined size to manufacture the optical element 100, the plurality of optical elements 100 can be easily manufactured.

A second embodiment of the present invention will be described with reference to FIGS.
FIG. 4 shows a cross section of the electro-optical device according to the second embodiment, and FIG. 5 shows a plan view of the electro-optical device.
4, the electro-optical device 1 includes a flat cover glass 10 as an optical element, a liquid crystal panel 20 provided on the cover glass 10, a dustproof glass 24 provided on the liquid crystal panel 20, and a cover for these. A frame (not shown) that holds the peripheral edges of the glass 10, the liquid crystal panel 20, and the dust-proof glass 24, and a cable (not shown) that is connected to the liquid crystal panel 20 and supplies electric power from the outside.

As shown in FIGS. 4 and 5, the cover glass 10 includes a translucent substrate 11 in which the incident light In is incident from one main surface and the optical region L is set at a central portion of the plane, and the translucent substrate. The light-transmitting substrate 11, the light-shielding film 12, and the liquid crystal panel 20 include a light-shielding film 12 serving as an optical functional film that functions as a frame that defines the optical region L of 11 and is provided on a plane on the light emission side. They are bonded to each other with an adhesive layer 13 made of an ultraviolet curable adhesive.
The translucent substrate 11 is a substrate formed of a material such as quartz, alkali-free glass, crystal, sapphire, lithium niobate (LiNbO ₃ : LN), lithium tantalate (LiTaO ₃ : LT), for example. The translucent substrate 11 is formed in an outer peripheral rectangular shape in a plan view in which a vertical dimension is a predetermined dimension, for example, a vertical dimension is 10 mm to 30 mm and a horizontal dimension is 13 mm to 40 mm.
The optical region L has an outer peripheral rectangular shape in plan view, and the position of each side is set with an appropriate dimension from each side of the translucent substrate 11, for example, 2 mm. This dimension differs depending on the type and size of the electro-optical device 1.
An antireflection film AR is provided on the main surface on which light of the translucent substrate 11 is incident.

As shown in FIG. 5, the light shielding film 12 is disposed in the outer peripheral region E that is out of the optical region L, and its main surface is formed in a belt shape having a predetermined width, for example, 2 mm.
The light shielding film 12 has a structure including a reflective layer 121 that reflects light incident on the light transmissive substrate 11 and an absorption layer 122 that is laminated on the reflective layer 121 and absorbs light.
The reflective layer 121 is a high reflectance film, and the absorption layer 122 is a low reflectance film.
Here, as the material constituting the reflection layer 121 and the material constituting the absorption layer 122, for example, the case where the reflection layer 121 is formed from chromium and the absorption layer 122 is formed from chromium oxide can be considered.

  In the electro-optical device 1 having this configuration, when the incident light In enters from outside the optical region L of the translucent substrate 11, it is reflected at the boundary surface between the translucent substrate 11 and the reflective layer 121. When the incident light In is incident obliquely with respect to the normal line of the translucent substrate 11, it passes through the translucent substrate 11, the adhesive layer 13, and the liquid crystal panel 20 and is reflected inside the liquid crystal panel 20 to be reflected light. However, when this reflected light enters the absorption layer 122, it is absorbed by the absorption layer 122. As described above, the light shielding film 12 has a function of efficiently reflecting the incident light In to suppress the transmittance and suppressing the reflected light from the liquid crystal panel 20.

A recognition mark M is formed on the surface of the translucent substrate 11 facing the reflective layer 121 by an ink jet method. In FIG. 3, the recognition mark M is displayed as the symbol “ABC”, as in the first embodiment. In the present embodiment, in consideration of the case where the light shielding film 12 is made of a colored material, the recognition mark M is recognized through the translucent substrate 11. Further, the color of the recognition mark M is set in consideration of the red color (R), the green color (G), and the blue color (B). Also in this embodiment, the position where the recognition mark M is displayed is not limited to the lower side, but may be the corner of the optical element 10.
The adhesive layer 13 is an ultraviolet curable adhesive or other adhesive, and is composed of an adhesive having the same refractive index as that of the translucent substrate 11.

In FIG. 4, the liquid crystal panel 20 is called a liquid crystal light valve, and includes a flat rectangular counter substrate 21 provided on the absorption layer side, a liquid crystal unit 22 laminated on the counter substrate 21, and a liquid crystal A TFT substrate 23 that is stacked on the portion 22 and has the same size as the counter substrate 21, and a dust-proof glass 24 is stacked on the TFT substrate 23.
The liquid crystal unit 22 includes a sealing material 221 provided on the outer peripheral edge of the counter substrate 21 and the TFT substrate 23, and a liquid crystal 222 accommodated in the sealing material 221.

As the counter substrate 21, a quartz substrate or a glass substrate is used.
A transparent electrode that applies a driving voltage to the liquid crystal 222 together with a pixel electrode (not shown) in a region in contact with the liquid crystal 222 on a surface facing the liquid crystal unit 22 of the counter substrate 21, for example, a counter electrode (for example, an ITO electrode made of an ITO film) (Not shown) is formed over the entire surface.
As the TFT substrate 23, a quartz substrate, a glass substrate, or a silicon substrate is used.
The area facing the liquid crystal unit 22 of the TFT substrate 23 and in contact with the liquid crystal 222 is composed of a transparent electrode that forms a pixel and applies the driving voltage of the liquid crystal 222 together with the counter electrode, for example, ITO. A pixel electrode (not shown) is disposed.
A rubbing alignment film (not shown) is provided on the pixel electrode of the TFT substrate 23, and similarly, the rubbing alignment film (see FIG. Not shown). These alignment films are comprised from transparent organic films, such as a polyimide film, for example.
As the dust-proof glass 24, a quartz substrate or a glass substrate is used. The dustproof glass 24 and the TFT substrate 23 are bonded and fixed with an adhesive, and an antireflection film AR is provided on the surface of the dustproof glass 24 opposite to the surface facing the TFT substrate 23.

Next, a method for manufacturing the electro-optical device 1 according to the second embodiment will be described with reference to FIGS.
[Method for Manufacturing Optical Element]
First, as shown in FIG. 6A, a large substrate 11A is prepared. By dividing the large substrate 11A into a plurality (nine in FIG. 6), one substrate of the light-transmitting substrate 11 shown in FIGS. 4 and 5 is obtained.
Printing is performed by an inkjet method in a state where the recognition mark M “ABC” is reversed left and right at a position corresponding to each light-transmitting substrate 11 at a predetermined position of the large-sized substrate 11A. That is, in this embodiment, since the recognition mark M printed on the back surface of the translucent substrate 11 is recognized from the front side of the translucent substrate 11, the recognition mark M printed on the translucent substrate 11 is left and right. Inverted state.
As shown in FIG. 6B, a large-sized substrate is formed by vapor deposition, sputtering, or other methods to form the reflective layer 121 so as to cover the recognition mark M displayed horizontally reversed. As shown in FIG. 6C, a low reflectance layer 122A is formed on the high reflectance layer 121A by vapor deposition, sputtering, or other methods to form the absorption layer 122. Film.

As shown in FIG. 7D, the portions corresponding to the optical regions L of the low reflectance layer 122A and the high reflectance layer 121A are etched. Therefore, a mask (not shown) in which an opening having the same size as that of the optical region L is provided in advance is disposed on the low reflectance layer 122A, and an etching solution is immersed from above the mask.
Thereafter, as shown in FIG. 7E, a large-sized substrate is divided into a plurality of pieces by a dicing apparatus or other apparatus to manufacture a cover glass 10 as one optical element.

[Bonding optical elements and liquid crystal panels]
The counter substrate 21, the liquid crystal unit 22, and the TFT substrate 23 are bonded to manufacture the liquid crystal panel 20, and a dustproof glass 24 is bonded to the TFT substrate 23. An ultraviolet curable adhesive constituting the adhesive layer 13 is applied to one of the counter substrate 21 and the optical element 10 of the liquid crystal panel 20 and bonded together, and then the adhesive layer 13 is ultraviolet cured.

Therefore, in 2nd Embodiment, there can exist the following effect other than the same effect as (1) (3) of 1st Embodiment.
(4) Since the optical function film is the light-shielding film 12 in which the reflective layer 121 and the absorption layer 122 are laminated, even if the light passes through the recognition mark M, the light is reflected by the reflective layer 121, and the absorption layer The light incident on 122 is absorbed by the absorption layer, and even if the recognition mark M is provided, the function of the light shielding film 12 itself is not impaired.

(5) Since the electro-optical device 1 includes the optical element 10 described above, the electro-optical device 1 can be identified by providing the type of the electro-optical device or the like as the recognition mark M, and the projection type image The operation of incorporating the electro-optical device 1 into the apparatus and other electronic devices can be easily performed.
In addition, in 2nd Embodiment, it is not limited to the structure which provides the recognition mark M between the translucent board | substrate 11 and the reflection layer 121, but as FIG. 8 shows, the reflection layer 121, the absorption layer 122, and Even if it is provided between the two, the same effects as described above can be obtained. However, if the recognition mark M is provided between the translucent substrate 11 and the reflective layer 121, the recognition mark M provided directly on the translucent substrate 11 can be easily recognized through the translucent substrate 11. On the other hand, as shown in FIG. 8, when the recognition mark M is provided between the reflective layer 121 and the absorption layer 122, the recognition mark M is recognized from the back side of the optical element 10 through the absorption layer 122. be able to.

Next, a third embodiment of the present invention will be described with reference to FIGS. The third embodiment has a structure in which the first embodiment and the second embodiment are combined.
FIG. 9 shows a cross section of the electro-optical device according to the third embodiment, and FIG. 10 shows a plan view of the electro-optical device.
As shown in FIGS. 9 and 10, the cover glass 10 functions as a frame defining the optical region L of the translucent substrate 11 and the translucent substrate 11 and is provided on a plane on the side from which light is emitted. A light shielding film 12 as an optical functional film and an antireflection film AR as an optical functional film provided on the incident side of the light transmissive substrate 11 are provided. The light transmissive substrate 11 and the light shielding film 12 and the liquid crystal panel 20 are bonded. Layers 13 are joined together. Note that the antireflection film AR is shown thick in order to make the structure easy to understand.

  As shown in FIG. 9, the first recognition mark M1 is formed on the surface of the translucent substrate 11 facing the antireflection film AR by the ink jet method. The first recognition mark M1 is formed by the same method as the recognition mark M of the first embodiment. A second recognition mark M2 is formed on the surface of the translucent substrate 11 facing the reflective layer 121 by an ink jet method. The second recognition mark M2 is formed by the same method as the recognition mark M of the second embodiment.

Therefore, in the third embodiment, the following operational effects can be achieved in addition to the operational effects shown in (1) to (5) of the first and second embodiments.
(6) The first recognition mark M1 printed by the ink jet method is provided on the outer surface of the translucent substrate 11 disposed on the light incident side of the liquid crystal panel 20 and out of the optical region L. Since the recognition mark M is covered with the antireflection film AR and the second recognition mark M2 is provided between the light-transmitting substrate 11 and the light-shielding film 12, a large amount of information can only be given to the electro-optical device 1. In addition, when the electro-optical device 1 is installed in the apparatus, even if it is difficult to recognize one identification mark, the other identification mark can be recognized.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. The fourth embodiment is different from the third embodiment in the position where the second recognition mark M2 is provided, and the other configuration is the same as that of the third embodiment.
FIG. 11 shows a cross section of the electro-optical device of the fourth embodiment, and FIG. 12 shows the back surface of the electro-optical device.
As shown in FIG. 11, the electro-optical device 1 includes a flat cover glass 10 as an optical element, a liquid crystal panel 20 provided on the cover glass 10, and a dustproof as an optical element provided on the liquid crystal panel 20. A glass 24, a frame (not shown) that holds the periphery of the cover glass 10, the liquid crystal panel 20, and the dust-proof glass 24, and a cable (not shown) that is connected to the liquid crystal panel 20 and supplies electric power from the outside. Has been.

As shown in FIGS. 11 and 12, the dust-proof glass 24 includes a translucent substrate 240 and an antireflection film AR as an optical functional film. The antireflection film AR is shown thick in order to make the structure easy to understand.
A first recognition mark M1 is formed by an inkjet method on the surface of the translucent substrate 240 facing the antireflection film AR. The first recognition mark M1 is formed by the same method as the recognition mark M of the first embodiment.
A second recognition mark M2 is formed on the surface of the translucent substrate 11 facing the reflective layer 121 by an ink jet method. The second recognition mark M2 is formed by the same method as the recognition mark M of the second embodiment. The second recognition mark M2 is displayed in the same manner as the recognition mark M shown in FIG.

Therefore, in the fourth embodiment, the following effects can be obtained in addition to the effects shown in (1) to (6) of the third embodiment and the second embodiment.
(7) Since the first recognition mark M1 is displayed from the back side of the electro-optical device 1 and the second recognition mark M2 is displayed from the front side, the recognition marks M1, M2 are displayed from both sides of the electro-optical device 1. Therefore, when the electro-optical device 1 is installed, the second recognition mark displayed on the other surface even if the first recognition mark M1 displayed on one surface is not visible. Since M2 will be visible, the usefulness at the time of product use improves.

Next, a fifth embodiment of the present invention will be described with reference to FIGS. The fifth embodiment is different from the fourth embodiment in that an identification mark having a different structure is used instead of the second recognition mark M2 in the fourth embodiment.
FIG. 13 shows a cross section of the electro-optical device according to the fifth embodiment, FIG. 14 shows a plane on the side from which light of the optical element constituting the electro-optical device is emitted, and FIG. 15 shows the electro-optical device. The enlarged cross section of the principal part of is shown.
In FIG. 13, the electro-optical device 1 includes a flat cover glass 10, a liquid crystal panel 20 provided on the cover glass 10, a dustproof glass 24 as an optical element provided on the liquid crystal panel 20, and these covers. A frame (not shown) that holds the peripheral edges of the glass 10, the liquid crystal panel 20, and the dust-proof glass 24, and a cable (not shown) that is connected to the liquid crystal panel 20 and supplies electric power from the outside.
The dust-proof glass 24 includes a translucent substrate 240 and an antireflection film AR as an optical functional film, and a recognition mark M is provided between the translucent substrate 240 and the antireflection film AR.

As illustrated in FIGS. 13 and 15, the light shielding film 12 includes a reflective layer 121 and an absorption layer 122. In this absorption layer 122, a recess 2 constituting the identification mark m is formed. The depth of this recess 2 is the same as the thickness of the absorption layer 122 in FIG. It is formed through. The edge of the recess 2 is separated from the edge of the absorption layer 122 on a plane.
The reflective layer 121 is a high reflectance film, and the absorption layer 122 is a low reflectance film.
Here, as a combination of the material constituting the reflective layer 121 and the material constituting the absorption layer 122, [1] When the reflection layer 121 is formed from chromium and the absorption layer 122 is formed from chromium oxide, [2] When the reflective layer 121 is formed from chromium and the absorption layer 122 is formed from titanium dioxide (TiO ₂ ), [3] When the reflective layer 121 is formed from aluminum and the absorption layer 122 is formed from chromium oxide, 4] The reflective layer 121 may be formed from silver and the absorbing layer 122 may be formed from titanium dioxide or chromium oxide.

  In the electro-optical device 1 having this configuration, as shown in FIG. 15, when incident light In enters from outside the optical region L of the translucent substrate 11, the boundary between the translucent substrate 11 and the reflective layer 121. Reflected by the surface. When the incident light In is incident obliquely with respect to the normal line of the translucent substrate 11, it passes through the translucent substrate 11, the adhesive layer 13, and the liquid crystal panel 20 and is reflected inside the liquid crystal panel 20 to be reflected by the reflected light Rf. However, when the reflected light Rf is incident on the absorbing layer 122, the reflected light Rf is absorbed by the absorbing layer 122 without being reflected again (without generating the reflected light Rf indicated by an imaginary line). As described above, the light shielding film 12 has a function of efficiently reflecting the incident light In to suppress the transmittance and suppressing the reflected light from the liquid crystal panel 20. The reflective layer 121 also has a role of reflecting light toward the light source and reusing the light.

In FIG. 14, the identification mark m is displayed as a symbol “ABC”. In the present embodiment, in addition to the characters “ABC”, other alphabets, Japanese characters, characters for constituting other languages, numbers, symbols, figures, barcodes, and the like can be identified. If there is, the kind is not limited. Further, in the present embodiment, the identification mark m is displayed in a large size so that it can be easily read. The position where the identification mark m is displayed is the lower side of the planar rectangular optical element 10 in FIG. 14, but may be the corner of the optical element 10.
“ABC” is recognized as an identification mark on the translucent substrate 11 from the incident light side plane due to the difference in color caused by the difference in material between the reflective layer 121 and the absorbing layer 122.
The adhesive layer 13 is an ultraviolet curable adhesive or other adhesive, and is composed of an adhesive having the same refractive index as that of the translucent substrate 11.

Next, a method for manufacturing the electro-optical device 1 of the present embodiment will be described.
[Method for producing cover glass]
The manufacturing method of the cover glass 10 is demonstrated based on FIG.16 and FIG.17.
As shown in FIG. 16A, first, a large substrate 11A is prepared. By dividing a plurality of large substrates 11A, nine in the figure, one substrate of the translucent substrate 11 shown in FIGS. 3 to 15 is obtained. An antireflection film AR is formed on one surface of the large substrate 11A by vapor deposition.
As shown in FIG. 16B, a high reflectivity layer 121A is formed by vapor deposition, sputtering, or other methods to form the reflective layer 121 on one surface of the large substrate 11A where the antireflection film AR is not formed. Then, on the high reflectivity layer 121A, the low reflectivity layer 122A is formed by vapor deposition, sputtering, or other methods in order to form the absorption layer 122. Here, the film thickness of the high reflectance layer 121A and the reflection layer 121 is the same, and the film thickness of the low reflectance layer 122A and the absorption layer 122 is the same. In the case where the material of the high reflectivity layer 121A is chromium and the material of the low reflectivity layer 122A is chromium oxide, the high reflectivity layer 121A is deposited on the main surface of the large substrate 11A, and then the deposition furnace ( An oxygen (O ₂ ) gas is introduced into the chamber), vapor deposition is performed while oxidizing chromium, and oxygen is mixed with sputtering, and sputtering is performed to form a film with a low reflectance layer 122A. Further, an etching stopper layer, for example, a layer of SiO ₂ is sandwiched between the high reflectance layer 121A and the low reflectance layer 122A which is an absorption layer, if necessary.

Thereafter, as shown in FIG. 16C, the recess 2 is formed by etching in the low reflectance layer 122A constituting the absorption layer 122, and an identification mark “ABC” is formed at a position corresponding to each light-transmitting substrate 11. Display m.
Therefore, a photoresist is applied to the entire surface of the multilayer film including the high reflectance layer 121A and the low reflectance layer 122A formed on the large substrate 11A. Then, using an exposure device such as a stepper or a mask aligner (not shown), the photo mask is overlaid and exposed in a marking pattern. Thereafter, development is performed to remove the resist corresponding to the recognition mark M. Further, only the low reflectance layer 122A constituting the absorption layer 122 of the multilayer film constituting the light shielding film layer 1 is etched by etching the region where the multilayer film that becomes the light shielding film layer 12 is exposed in a marking shape after the resist is removed. By removing (half etching) by etching, the recess 2 is formed. Here, half-etching is stopped by using the etching stopper layer made of SiO ₂ or the like as described above. In the case where the etching stopper layer is not provided, the time is managed for half etching. Thereafter, the resist is peeled off.

As shown in FIG. 17D, the light shielding film layer 12 is formed in a frame shape, and the substrate main surface in the region of the optical region L is exposed. First, a photoresist is applied to the entire surface of the multilayer film of the high reflectance layer 121A and the low reflectance layer 122A corresponding to the light shielding film 12, and further, using an exposure device such as a stepper or a mask aligner (not shown), The pattern is exposed by overlaying a photomask (according to the shape of the frame). Thereafter, development is performed to remove unnecessary portions, that is, the resist on the optical region L. The resist is removed, and the region where the multilayer film of the high reflectance layer 121A and the low reflectance layer 122A is exposed is etched to pattern the light shielding film layer 12 in a frame shape (only the portion where the resist is removed is etched). When the etching stopper layer is provided, a different type from the etching solution used in the above-described process, that is, an etching solution capable of etching and removing the etching stopper layer is used. Thereafter, the resist is peeled off.
Furthermore, as shown in FIG. 17E, a large substrate 11A is divided into a plurality of pieces by a dicing apparatus or other apparatus, and in this embodiment, it is divided into nine pieces, and one cover glass 10 is manufactured.

[Join of cover glass, liquid crystal panel, dustproof glass]
The liquid crystal panel 20 is manufactured by bonding the counter substrate 21, the liquid crystal unit 22, and the TFT substrate 23, and an ultraviolet curable adhesive that forms the adhesive layer 13 on one of the counter substrate 21 and the cover glass 10 of the liquid crystal panel 20. After applying the agent and bonding them together, the adhesive layer 13 is cured with ultraviolet rays.
Further, the recognition mark M is printed on one surface of the translucent substrate 240 constituting the dustproof glass 24 by an ink jet method, and the antireflection film AR is formed thereon by vapor deposition or other methods. The dust-proof glass 24 is bonded to the liquid crystal panel 20 with an adhesive to manufacture the electro-optical device 1.

Therefore, in the fifth embodiment, the following operational effects can be achieved in addition to the same operational effects as in the fourth embodiment.
(8) The cover glass 10 is provided in the translucent substrate 11 in which the optical region L is provided on the main surface, and in the peripheral region E off the optical region L of the translucent substrate 11 and is incident on the translucent substrate 11. And a light-shielding film 12 having an absorption layer 122 that absorbs light, and a recess 2 that is formed in the thickness direction of the absorption layer 122 in a peripheral region E that is out of the optical region L. An identification mark m is provided. In the present embodiment, since the identification mark m is in a region outside the optical region of the translucent substrate 11, the original function as the optical element 10 is not hindered and the identification mark m can be recognized. In addition, since the identification mark m is formed not on the reflective layer 121 but on the absorbing layer 122, stray light in the optical element 10 can be reduced.

(9) The depth of the recess 2 is the same as the thickness of the absorption layer 122, that is, since the recess 2 is formed through the absorption layer 122, based on the color difference between the absorption layer 122 and the reflection layer 121, The recognition mark M can be easily recognized.

(10) In manufacturing the cover glass 10, a high reflectance layer 121A constituting the reflective layer 121 is formed on the translucent substrate 11, and the low reflectance layer constituting the absorbing layer 122 is formed on the high reflectance layer 121A. Since 122A is formed and the concave portion 2 constituting the recognition mark M is formed by etching in the thickness direction of the low reflectance layer 122A, the concave portion 2 can be easily formed by simple means of etching. Therefore, the cover glass 10 can be manufactured at low cost.

(11) If the high reflectivity layer 121A is formed from chromium and the low reflectivity layer 122A is formed from chromium oxide, chromium oxide can be formed by sputtering with oxygen mixed with chromium. Film formation can be performed easily.

In the fifth embodiment, the configuration of the light shielding film 12 is not limited to the configuration shown in FIGS. 13 and 15, and may be the configuration shown in FIGS. 18 and 19, for example.
FIG. 18 shows an enlarged cross section of the main part of an electro-optical device according to a modification of the fifth embodiment.
18, the electro-optical device 1 includes a flat cover glass 30, a liquid crystal panel 20 provided on the cover glass 30, a dustproof glass 24 (see FIG. 13), the cover glass 30, and the liquid crystal panel 20. And a frame (not shown) that holds the periphery of the dustproof glass 24 and a cable (not shown) that is connected to the liquid crystal panel 20 and supplies electric power from the outside.

The cover glass 30 includes a light-transmitting substrate 11 and a light-shielding film 32 that functions as a frame that defines the optical region L of the light-transmitting substrate 11, and the light-transmitting substrate 11, the light-shielding film 32, the liquid crystal panel 20, and the like. Are bonded to each other by an adhesive layer 13.
The light shielding film 32 has a structure including a reflective layer 121 and an absorption layer 122 and a third layer 123 that absorbs light provided between the reflection layer 121 and the absorption layer 122.
The reflective layer 121 is composed of a high reflectance layer made of chrome.
The absorption layer 122 is composed of a low reflectivity layer made of chromium oxide, and the concave portion 2 constituting the recognition mark M is formed as in the first embodiment.
The third layer 123 is made of a material that absorbs light and is less likely to be corroded by the etchant than chromium oxide that is the material of the absorption layer 122, for example, titanium oxide.
The size of the third layer 123 on the plane is the same as the size of the reflective layer 121 and the absorption layer 122 on the plane.

The method of manufacturing the above cover glass 30 is almost the same as that of the first embodiment, and a high-reflectance layer 121A for forming the reflective layer 121 is formed on the large substrate 11A by vapor deposition, sputtering, or other methods. Thereafter, an intermediate layer constituting the third layer 123 is formed by vapor deposition, sputtering or the like in accordance with the size of the large substrate 11A, and an absorption layer 122 is formed on the intermediate layer constituting the third layer 123. In order to achieve this, the low reflectance layer 122A is formed by vapor deposition, sputtering, or other methods.
After the recess 2 constituting the recognition mark M is formed in the low reflectance layer 122A by etching, etching is performed to form the optical region L in the central portion of the low reflectance layer 122A, the intermediate layer, and the high reflectance layer 121A. To do.
In the light shielding film 32 shown in FIG. 18, since the third layer 123 that absorbs light is provided between the absorption layer 122 and the reflection layer 121, the third layer 123 together with the absorption layer 122 is used for the electro-optical device 1. Internal stray light can be reduced.
Since the third layer 123 is made of titanium oxide, which is less susceptible to corrosion by the etchant than the absorbing layer 122, the third layer 123 has a function as an etching stopper. Therefore, the absorption layer 122 can be sufficiently etched, and accordingly, the recognition mark M can be provided that is easy to recognize by forming the recess 2 reliably.

FIG. 19 shows an example in which the shape of the recess formed in the absorption layer 122 is different from that in FIG. In FIG. 19, the absorption layer 122 is formed with a recess 4 constituting the identification mark m, and the depth of the recess 4 is smaller than the thickness of the absorption layer 122 unlike the structure of FIG. 15, in other words, The absorption layer 122 is halfway through the thickness. In the present embodiment, the identification mark m can be recognized by the shade when the concave portion 4 is irradiated with light.
The recess 4 can be formed by laser irradiation as well as etching. When etching is used, the etching is performed by adjusting the concentration of the etching solution and the etching time.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
The sixth embodiment is a projection type video apparatus (projection type liquid crystal projector) using the electro-optical device 1 described in detail above as a light valve.
FIG. 20 shows a schematic configuration of the projection type video apparatus.
In FIG. 20, a projection type video apparatus 1100 according to the present embodiment prepares three liquid crystal modules including a liquid crystal device having a drive circuit mounted on a TFT array substrate, and is used as RGB light valves 100R, 100G, and 100B, respectively. It is configured as the projector used. The electro-optical device 1 is used for these light valves 100R, 100G, and 100B.
In the projection type image device 1100, when projection light is emitted from a lamp unit 1102 of a white light source such as a metal halide lamp, light components R and G corresponding to the three primary colors of RGB are obtained by three mirrors 1106 and two dichroic mirrors 1108. , B and led to the light valves 100R, 100G, 100B corresponding to the respective colors. At this time, the B light is guided through a relay lens system 1121 including an entrance lens 1122, a relay lens 1123, and an exit lens 1124 in order to prevent light loss due to a long optical path. The light components corresponding to the three primary colors modulated by the light valves 100R, 100G, and 100B are synthesized again by the dichroic prism 1112 and then projected as a color image on the screen 1120 via the projection lens 1114 as the projection optical device. Is done.

Therefore, in the sixth embodiment, the same operational effects as those of the second embodiment can be achieved, and the following operational effects can be achieved.
(12) Since the lamp unit 1102, the electro-optical device 1 that modulates light from the lamp unit 1102 according to image information, and the projection lens 1114 that projects the light modulated by the electro-optical device 1 are provided. It is possible to provide a projection type video apparatus capable of producing the above-described effects.

Note that the present invention is not limited to the above-described embodiment, and includes the following modifications as long as the object of the present invention can be achieved.
For example, in the above-described embodiment, the electro-optical device 1 is used for a projection-type image device, but in the present invention, it can also be used for an electronic device such as a digital camera. Further, as an example of the electro-optical device 1, an optical low-pass filter may be used.
Further, in each of the embodiments, the light shielding films 12 and 32 are formed along the four sides of the planar rectangular translucent substrate 11, but the present invention is not limited to this.
Further, in manufacturing the optical elements 10 and 100, the large-sized substrate 101A is used. However, a light-transmitting substrate 11 or 101 obtained by dividing the substrate 101A may be used.

  The present invention can be used for a projection type video apparatus and other electronic devices.

  DESCRIPTION OF SYMBOLS 1 ... Electro-optical device, 10, 100 ... Optical element, 11, 101, 240 ... Translucent substrate, 12, 32 ... Light-shielding film (optical function film), 13 ... Adhesive layer, 20 ... Liquid crystal panel, 21 ... Opposite substrate , 22 ... Liquid crystal part, 23 ... TFT substrate, 24 ... Dust-proof glass, 121 ... Reflective layer, 122 ... Absorbing layer, 1100 ... Projection type image device, L ... Optical region, E ... Peripheral region, M ... Recognition mark, M1 ... 1st recognition mark M2 ... 2nd identification mark, AR ... Antireflection film (optical functional film)

Claims (9)

A translucent substrate;
A recognition mark provided in a peripheral region outside the optical region of the translucent substrate;
An optical functional film provided on the main surface of the translucent substrate so as to cover the recognition mark;
An optical element comprising:
The optical element, wherein the recognition mark is printed on the main surface of the translucent substrate by an ink jet method. The optical element according to claim 1,
The optical element, wherein the optical functional film is an antireflection film. The optical element according to claim 1,
The optical functional film is a light shielding film provided in a peripheral region off the optical region of the translucent substrate, and the light shielding film includes a reflective layer that reflects light incident on the translucent substrate; An absorption layer that absorbs light,
The reflection layer and the absorption layer are laminated in order on the surface of the translucent substrate. The optical element according to claim 3,
The optical element, wherein the recognition mark is provided between the translucent substrate and the reflective layer. The optical element according to claim 3,
The optical element according to claim 3, wherein the recognition mark is provided between the reflective layer and the absorbing layer. An optical element according to claim 1 or 2, and a liquid crystal panel,
An electro-optical device, wherein a main surface of the translucent substrate on which the recognition mark is not provided is opposed to the liquid crystal panel. An optical element according to any one of claims 3 to 5, and a liquid crystal panel,
An electro-optical device, wherein a main surface of the light-transmitting substrate on the side where the light-shielding film is provided is opposed to the liquid crystal panel. A light source, an electro-optical device that modulates light from the light source according to image information, and a projection optical device that projects light modulated by the electro-optical device,
8. The projection type image device according to claim 6, wherein the electro-optical device is an electro-optical device.   A recognition mark is printed on the main surface of the peripheral region outside the optical region of the translucent substrate by an ink jet method, and an optical functional film is provided on the main surface of the translucent substrate so as to cover the recognition mark. A method for manufacturing an optical element.

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