JPS6088902A - Color separation filter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a color separation filter, and more particularly, it is composed of a multilayer interference thin film used in full-color liquid crystal display devices, image pickup tube type color cameras, solid-state color cameras, color digital cameras, etc. The present invention relates to a color separation filter that transmits light of a predetermined wavelength.

Technical background of the invention and its problems Typical color separation filters used in full-color liquid crystal display devices include organic dye filters and multilayer interference film filters. Among these, organic dyed filters are
Since organic dyes are used to dye the filters, they inevitably suffer from poor physical properties such as heat resistance and light resistance. On the other hand, color separation filters made of multilayer interference films have the advantage of being superior in light resistance, heat resistance, chemical resistance, and cleaning resistance because the multilayer interference film is generally made of inorganic materials. Shi, it's attracting attention.

However, this color separation filter made of a multilayer interference film is manufactured by laminating a high refractive index dielectric layer and a low refractive index dielectric layer by laminating a total of about one layer while strictly controlling the optical film thickness. The disadvantage is that the manufacturing process becomes significantly more complex. Note that the optical film thickness is defined as the refractive index of the substance that makes up the film.
It means the value nd when the film thickness is d. Further, this type of color separation filter has the disadvantage that its spectral transmittance characteristics are unstable. In other words, the phenomenon in which the transmittance changes as the wavelength changes in the transmission region (the so-called ripple phenomenon) is recognized to be quite large, and the transmittance is negligibly small even in the reflective head-mounted mode. was there.

OBJECTS OF THE INVENTION AND SUMMARY OF THE INVENTION The present invention aims to solve all at once the drawbacks associated with color separation filters made of multilayer interference films as described above, and has the following objects.

(a) To provide a color separation filter having a spectral transmittance characteristic in which light transmittance due to a change in wavelength and light transmittance in a reflective region is extremely small in a spectral region.

(bJ) Even if the number of laminated films of high refractive index 8 electric layers and low refractive index dielectric layers is reduced compared to the conventional one, the spectral transmittance characteristics are deteriorated, and therefore the manufacturing process is simplified5. Provide color separation filters.

A color separation filter according to the present invention capable of achieving the above objects includes a high refractive index dielectric layer on a substrate having an optical film thickness of -λ for light of a predetermined wavelength λ, and ≠ the optical film thickness 7. In a multilayer interference film type color separation filter provided with a laminate formed by alternately laminating low refractive index dielectric layers of 72 and λ or more layers, there is a layer between the (-) substrate and the laminate. /, / :/, a high refractive index dielectric layer having an optical thickness of J−λ≠ and one and two/
, 2-λ of low refractive index dielectric layers are provided on the substrate in this order, (b) the low refractive index dielectric layer on the side of the laminate farthest from the substrate; a high refractive index dielectric layer having an optical thickness of −λ, a low refractive index dielectric layer having an optical thickness of 2λ, −
A high refractive index dielectric layer having an optical thickness of ≠ ≠ and, if necessary, a low refractive index dielectric layer having an optical thickness of 1/,02,0−λ. , are provided in this order.

Conventionally, in color separation filters made of multilayer interference films,
The optical thickness of the high refractive index dielectric layer and the low refractive index dielectric layer is
It has been thought that it is possible to obtain a color separation filter with excellent spectral transmittance characteristics by strictly controlling −λ, but in the color separation filter of the present invention, By consciously changing the optical film thicknesses of the high refractive index dielectric layer and the low refractive index dielectric layer laminated on the side away from - to specific values such as 7λ, quite unexpectedly, A color separation filter having extremely excellent spectral transmittance characteristics can be obtained.Moreover, as in the present invention, the optical film thickness of the high refractive index dielectric layer and the low refractive index dielectric layer on the side closest to the substrate and the side furthest from the substrate is By setting ? to a specific value, a color separation filter having excellent spectral transmittance characteristics can be obtained even when the number of laminated layers of high refractive index dielectric layers and low refractive index dielectric layers is reduced compared to conventional ones.

3. Detailed Description of the Invention The present invention will be explained below with reference to preferred embodiments shown in the drawings.

As shown in FIG. 1, the color separation filter according to the present invention has a high refractive index dielectric first layer H1 having an optical film thickness of 2/3λ laminated on a substrate.
0! two! A low refractive index material cylinder 1ML1 having an optical thickness of i-λ is laminated. Then, on this low refractive index dielectric first JiiL1, a high refractive index dielectric fourth layer H2 having an optical thickness of 7λ and a low refractive index dielectric second layer L2 having an optical thickness of 7λ are laminated, and further On this low refractive index dielectric layer L2, three high refractive index dielectric layers H3 having an optical thickness of 7λ and a third low refractive index dielectric layer L5 having an optical thickness of /jλ are laminated. ing. In this way, the high refractive index dielectric layers HK, 5.6 and the low refractive index dielectric layers Lli, 5.6, which similarly have an optical thickness of 7λ, are sequentially and alternately laminated. Then, on the low refractive index dielectric layer t) NL6, a high refractive index dielectric seventh layer H7 having an optical thickness of 7λ and/or 0
:Low refractive index dielectric having an optical film thickness of 1,2λ≠ The seventh layer L7 is laminated in this order. Sara/,
/~7.3 on this low refractive index dielectric cylinder 7 L7.

A high refractive index dielectric layer r layer H8 having an optical thickness of λ is deposited. As described above, the optical film thickness means the value nd when the refractive index of the material constituting the film is n and the film thickness is d.

Next, a color separation filter according to another specific example of the present invention will be explained. This color separation filter is placed on the substrate l, as shown in FIG.

One high refractive index dielectric layer H1 having an optical thickness of λ is i,
10.2 A low refractive index dielectric first layer L1 having an optical thickness of □λ is laminated. And this low refractive index dielectric first layer L1
On top, a high refractive index dielectric second layer H having an optical thickness of 7λ.
A low refractive index dielectric second layer L2 having an optical film thickness of 2 and 7λ is laminated, and this low refractive index dielectric foil 2 layer L2 is further laminated.
A high refractive index dielectric layer 3 having an optical thickness of jλ is formed above.
A layer H5 and a third low refractive index dielectric layer L5≠ having an optical thickness of Lλ are laminated. In this way, the high refractive index dielectric layers 26 and the low refractive index dielectric layers LK, 5.6, which similarly have an optical thickness of 7λ, are sequentially and alternately laminated. Then, on the low refractive index dielectric first layer L6, a high refractive index dielectric seventh layer 7 having an optical thickness of 7λ and □λ preferably M01. -/, 2λ optical film 1, O~1. A seventh layer L7 of low refractive index dielectric material having a thickness of 100 mm is laminated in this order. Furthermore, this low refractive index dielectric cylinder 7 L7
On top /, /云High refractive index with an optical film thickness of 1,3λ /, 0 ~
2.0 refractive index material cylinder r layer H8 and □λ layer L8 are preferably laminated in this order. ing. Furthermore, if the refractive index of the λ1r point is n and its film thickness is d, it means the value nd.

As the substrate l, pine glass, quartz glass,
Transparent substrates such as synthetic quartz plates, optical resin plates, transparent resin films, cathode ray tube substrates, solid-state image sensors, etc. are used.5 As the high refractive index material forming the high refractive index dielectric layer, T
i0z (refractive index n = 2.2), 5b205 (
n = 2, θ≠), CaO2 (n = 2.1I2), Z
Examples include rO2 (n = 10), Zn5 (n = 2.3), and the like. In addition, as a low refractive index material forming a low refractive index dielectric layer, 1.5102 (n = I, uA
), CaF2 (n = 1.23), MgFz (
n = /, 31).

Among these, a combination of Ti0g as a high refractive index material and 902 as a low refractive index material is preferable because of the surface force of stress relaxation between the layers when laminating multiple layers.

The high refractive index dielectric layer and the low refractive index dielectric layer are laminated by a film forming method such as a vapor deposition method or a spuckling method. The optical film thickness of these dielectric layers is controlled by a film thickness monitoring device such as a photoelectric film thickness meter.

The total number of gf layers, the total of the high refractive index dielectric layer and the low refractive index dielectric layer laminated on the substrate, is preferably two or more layers, or f-p, and the transmittance in the reflective area is small. Since the lamination process becomes complicated, from a practical standpoint, about 2OR is sufficient.

In the color separation filter according to the present invention, the optical film thicknesses of the high refractive index dielectric layer and the low refractive index dielectric layer on the side closest to the substrate and the side furthest from the substrate are controlled to specific values.
It has excellent spectral transmittance characteristics, and this excellent spectral transmittance characteristic makes it possible to reduce the total number of laminated layers of optical films, high refractive index dielectric layers and low refractive index dielectric layers with a thickness of Vλ, compared to conventional optical films. It is maintained even if the number of films is decreased compared to the number of multilayer interference films.

Laminated between a high refractive index dielectric layer and a low refractive index dielectric layer that are laminated closest to the substrate, and a high refractive index dielectric layer and a low refractive index dielectric layer that are laminated on the side furthest from the substrate. The high refractive index dielectric layer and the low refractive index dielectric layer are laminated so that each has an optical thickness of 7λ, but this optical thickness has an tolerance of error within a few inches (usually 5 OA or less). It will be done.

The present invention will be further explained below with reference to examples, but the present invention is not limited to these examples. Set the glass substrate, then /
X 10 'Torr'! After exhausting the air, the substrate temperature was set to 0° C. for the 33 film. And Tl layered during vacuum deposition
In order to prevent O2 from being reduced to TIO or TI, 02 gas was
Ti o2 introduced at E and then set in the specified hearth
After thoroughly heating the pellet sample (manufactured by Merck & Co., Ltd.) by electron beam heating, the shutter was opened and Tl was deposited on the substrate.
O2 was deposited to an optical thickness of /,jλ. This vapor deposition is
The current value of the electron gun is 2! It was set to OmA.

The thickness of the Ti 02 film to be laminated is measured using a photoelectric film thickness meter by shining light from a projector onto a monitor glass set in advance and measuring the monitor wavelength λ. By receiving the reflected light with a light receiver and monitoring the relationship between the optical film thickness (nd) and the reflectance, the optical film thickness is 2λ. 〇Next, after stopping the introduction of 02 gas, the 5so2 sample (manufactured by Optron) placed in the designated hearth is heated with an electron beam, and after sufficiently preheating, the shutter is opened and the 5to2 film is placed on the TiO2 film. It was deposited to a film thickness of /, /2 optics≠. The optical thickness of the 8302 film is 'lIO2
A photoelectric film thickness meter was used in the same manner as for the film.

By repeating the same operation, the TlO2 film and the 5102 film are sequentially deposited on the stg2 film with the optical film thickness of -4 no λ≠ / / / / / / /, / alternately 7λ, 7λ, Vλ1, jλ, 7λ , 7λ, 7/I
I// λ, jλ, 7λ, jλ; 7→A total of 5 io layers were laminated with optical film thicknesses of 5 and 4, respectively.

Next, as the 13th layer, a TiO2 film having an optical thickness of Vλ was laminated on the Mogami J-Lab's Sl0g film by the same operation as above, and as the lμ layer, an optical film of -to/-λ [IK was turned to the right] A 5i02 film is laminated on the TiO2 film, and finally, a 'rto film having an optical thickness of λ is deposited on this as the first S layer.
The two films were laminated and slowly cooled at step 1 to bring the substrate temperature to 200° C., and then taken out into the atmosphere.

The spectral transmittance characteristics of the obtained multilayer interference film are expressed by the curve in Figure 2 (&
). As can be seen from FIG. 2, the multilayer interference film constituting the color separation filter according to the present invention has the advantage that it is sharp in θ and the light transmittance in the reflective region is extremely small. It has excellent spectral transmittance characteristics.

After forming a masking layer in a predetermined shape on this multilayer interference thin film, the multilayer interference film was dry etched with CF11 gas, and then the masking layer was peeled off to produce a striped color separation filter. In addition, this stripe color separation filter has a monitor wavelength of 6! Since it was set to rOnm, it had cyan characteristics.

A multilayer interference film was prepared in the same manner as in Example 1, except that TiO2 films and 5to2 films were alternately laminated on the comparative example substrate in 16 g layers each with an optical film thickness of 7λ. The spectral transmittance characteristics of this multilayer interference film are shown in curve (b) in Figure λ.

Example 1 A Pyrex glass substrate was set in a part of the substrate holder of a vacuum deposition apparatus in which an optical film thickness gauge was placed, and then /
X10-'Torr'! After exhausting with
O″C.Then, the TlO2 layered during vacuum evaporation
In order to prevent 02 gas from being reduced to TiO or TI, 02 gas was introduced at λX/(f''Torr'!), and then a 'rio2 pellet sample (manufactured by Merck & Co., Ltd.) set in a predetermined hearth was exposed to an electron beam. After sufficient breathing due to heating, the shutter is opened and TlO2 is deposited on the substrate.
, +2 Tλ optical film thickness. This vapor deposition reduces the current value of the electron gun to 1! I set it to Omk. Laminated Ti
The thickness of the O2 film can be measured using a photoelectric film thickness meter by shining light from a projector onto a monitor glass set in advance, setting the monitor wavelength λ to AjOnm, and receiving the reflected light with a receiver. ) and reflectance to obtain a μ optical film thickness of 1/, 2-λ! iii controlled.

Next, after stopping the introduction of 02 gas, the 5102 sample (manufactured by Optron) set at a predetermined nose was heated with an electron beam, and after sufficient breheating, the shutter was opened and the 8102 film was replaced with a TiO2 film. 7 on top. The optical film was deposited to an optical film thickness of /λ. The optical thickness of the 5102 film is TIO
The measurement was carried out using an optical film thickness meter in the same manner as in 2l1I4.

By repeating the same operation, Ti02 film and 5102
The films were sequentially laminated with 5 layers each, for a total of 10 layers, each having an optical film thickness of ////ノλ, 7λ, 7λ, and 7λ.

Next, as the 13th layer, a TlO2 film having an optical thickness of Vλ was laminated on the uppermost 3sozlI layer by the same operation as above, and a 5to2 film having an optical thickness of Lλ including Lλ was laminated as the 74th layer. Then, on top of this, a 13th layer and finally a 5102 film having an optical thickness of 7λ was laminated on top of this, with the first layer being the first layer, and the substrate was slowly cooled in a trench where the temperature reached 0. After that, it was taken out into the atmosphere.

The color separation filter made of the multilayer interference film obtained in this way has excellent spectral transmittance characteristics such that the light transmittance in the same category as the color separation filter of Example 1 is extremely small/less than 100%. was.

Example 3 An aluminum reverse etching pattern of a predetermined shape was formed on a Pyrex glass substrate using a conventional technique. Next, TiO2, which is a high refractive index dielectric material, and 5f02, which is a low refractive dielectric material, are placed on the substrate using a vacuum winding device equipped with an optical film thickness meter at a wavelength monitored by the optical film thickness meter. 6! Onm is the optical film thickness nd (n: refractive index, d:
59.The thickness of the film gradually increases. One layer was deposited in this order to form a multilayer interference film having cyan characteristics on the aluminum pattern. Next, a stripe pattern with cyan characteristics was obtained by stripping the aluminum (1) from this.Next, a film of cadmium sulfide was formed on the cyan pattern by vacuum evaporation, and then dry etching was performed. A silicon dioxide film was further layered on the resulting substrate to a thickness of !μm by vacuum evaporation, and the surface was polished to a smooth surface to form a color for frequency separation type image pickup tubes. A separation filter was produced.The spectral transmittance characteristics of the obtained filter had ideal characteristics as a color separation filter.

[Brief explanation of drawings]

1 and 2 are 1+fT plane views of the color separation filter according to the present invention, and FIG. 3 is a diagram showing the spectral transmittance characteristics of the color separation thermal filter according to the present invention and the conventional color separation filter. be. l... Color separation filter λ... Substrate Hl, 2. -1... High refractive index electric layer Ll, 2...
・ ... Low refractive index dielectric layer applicant's agent

Claims (1)

[Claims] 4. On a substrate, an optical film for light with a predetermined wavelength λ, a high refractive index dielectric layer having a thickness of l or Vλ, and a low refractive index dielectric layer having an optical film thickness of l or 7λ. In a multilayer interference film type color separation filter provided with a laminate in which two or more layers are alternately laminated, (a) between the substrate and the laminate, no.
A high refractive index dielectric layer having an optical thickness of ≠ and/or 0−;
(b) low refractive index dielectric layers having an optical thickness of 2λ are provided on the substrate in this order; , −λ
A high refractive index dielectric layer having an optical thickness of /, 0 nim2
A low refractive index dielectric layer having an optical thickness of λ and a high refractive index dielectric layer having an optical thickness of ´°' to ´°8λ are provided in this order. Color separation filter. 2. On the substrate, the optical film thickness for light with a predetermined wavelength λ is Lλ
A multilayer interference film type in which a laminate is provided in which a high refractive index dielectric layer having an optical thickness ≠ λ and a low refractive index dielectric layer having an optical thickness ≠ λ are alternately stacked on top In the color separation filter, /, /~/, J (a) between the substrate and the laminate, 4! A high refractive index dielectric layer having an optical thickness of -1λ and a low refractive index dielectric layer having an optical thickness of l+O~7.2 □λ are provided on the substrate in this order. b) on the low refractive index dielectric layer on the side of the laminate that is farthest from the substrate, a high refractive index dielectric layer having an optical thickness of λ/, and an optical thickness of 2 λ; ≠ A low refractive index dielectric layer having an optical thickness of il: i, sλ, a high refractive index dielectric layer having an optical thickness of θ to λ, O, and a low refractive index dielectric layer having an optical thickness of 7 λ, A patent claim characterized in that color separation filters 0 to 3 are provided in this order, the high refractive index dielectric layer is configured as TlO2, and the low refractive index dielectric layer is configured as 8102. The color separation filter according to the first or second range.