TWM628996U - Filter with adjustable and controllable spectrum - Google Patents

Abstract

A filter with adjustable and controllable spectrum includes a first optical filter, a second optical filter, and a third optical filter stacked with each other in a light-incident direction. The first optical filter is disposed on the second optical filter, and the second optical filter is disposed on the third optical filter. When a first voltage is applied, the first optical filter is configured to block the light in a first wavelength interval, and the second optical filter is configured to block the light in a second wavelength interval. When a second voltage is applied, the first optical filter and the second optical filter are configured to pass the light of all wavelengths. The third optical filter is configured to pass the light in the first wavelength interval and the second wavelength interval.

Description

Optical filter with adjustable spectrum

The present invention relates to an optical filter device, and in particular, to an optical filter with adjustable spectrum.

Optical filters have been widely used in various devices, such as photographic equipment, optical instruments, or image sensors. By absorbing or blocking specific wavelengths of light, filters allow the desired wavelengths of light to pass through, allowing the image to display the desired color.

However, under different requirements, users often need to replace different filters to achieve desired effects, which is extremely inconvenient for users. For example, photographers carry a variety of different filters to replace when various filter effects are desired. Therefore, there is an urgent need for a filter technology that can solve the above problems.

In view of this, one object of the present invention is to provide an optical filter with adjustable spectrum, which includes a filter that changes the filter spectrum as the voltage changes. Optical filters and filters with fixed spectrum. The filter spectrum of some of the filters in the filter can be changed by changing the voltage, so the filter can provide light in different wavelength ranges without changing the filter, thereby improving the filter's performance. Convenience and applicability.

According to the above purpose of the present invention, an optical filter with adjustable spectrum is proposed. The optical filter with adjustable spectrum includes a first optical filter, a second optical filter and a third optical filter which are stacked on each other in the light incident direction, the first optical filter is arranged on the second optical filter, the first optical filter The second filter is arranged on the third filter. When the first voltage is applied, the first filter is configured to block the passage of light in the first wavelength range, and the second filter is configured to block the passage of light in the second wavelength range. The first wavelength range light and the second wavelength range light have different wavelengths. When the second voltage is applied, the first filter and the second filter are configured to allow light in all wavelength ranges to pass through. The third filter is configured to allow the light of the first wavelength range and the light of the second wavelength range to pass, and to block the light of other wavelength ranges from passing.

According to an embodiment of the present invention, the above-mentioned first wavelength range light is infrared light wavelength range light.

According to an embodiment of the present invention, the light in the second wavelength range is light in the visible wavelength range.

According to an embodiment of the present invention, the first filter and the second filter include at least two first material layers and at least one second material layer, and the first material layers and the second material layers are alternately stacked. When the first voltage is applied, the first material layer and the second material layer have different refractive indices, and when the second voltage is applied, the first material layer and the second material layer have the same refractive index.

According to an embodiment of the present invention, the at least two first material layers both include silicon oxynitride.

According to an embodiment of the present invention, the at least one second material layer includes a liquid crystal material.

According to an embodiment of the present invention, the third filter is made of a material whose refractive index does not change with voltage.

According to an embodiment of the present invention, the first voltage is 0V.

According to an embodiment of the present invention, the second voltage is about 3V.

According to the above purpose of the present invention, another optical filter with adjustable spectrum is proposed. The optical filter with adjustable spectrum includes a first optical filter, a second optical filter, a third optical filter, and a fourth optical filter which are stacked on each other in the light incident direction, and the first optical filter is arranged on the second optical filter. On the filter, the second filter is arranged on the third filter, and the third filter is arranged on the fourth filter. When the first voltage is applied, the first filter is configured to block the passage of light in the first wavelength range, the second filter is configured to block the passage of light in the second wavelength range, and the fourth filter is configured to block the passage of the third wavelength range The wavelength range light passes through. The first wavelength range light, the second wavelength range light, and the third wavelength range light all contain different wavelengths. When the second voltage is applied, the first filter, the second filter, and the fourth filter are configured to pass light in all wavelength ranges. The third filter is configured to pass light of the first wavelength range, light of the second wavelength range, and light of the third wavelength range, and to block light of other wavelength ranges from passing through.

100: filter

110: The first filter

120: Second filter

130: Third filter

140: Fourth filter

D1: incoming light direction

n ₁ : refractive index

n ₂ : refractive index

V ₁ : the first voltage

V ₂ : the second voltage

λ ₁ : light in the first wavelength range

λ ₂ : light in the second wavelength range

The objects, features, advantages, and embodiments of the present disclosure can be more easily understood when read in conjunction with the accompanying drawings. It should be noted that, according to standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased in order to clarify the discussion.

FIG. 1 is a schematic diagram illustrating an optical filter with adjustable spectrum according to an embodiment of the present invention.

FIG. 2 is a graph showing the refractive index curves of the second material layer of a filter of an optical filter with adjustable spectrum according to an embodiment of the present invention when different voltages are applied.

3A and FIG. 3B respectively illustrate transmission spectra of the first filter according to an embodiment of the present invention when different voltages are applied.

4A and FIG. 4B respectively illustrate transmission spectra of the second filter according to an embodiment of the present invention when different voltages are applied.

FIG. 5 illustrates the transmission spectrum of a third filter according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating the transmission spectrum of an optical filter with adjustable spectrum according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating the transmission spectrum of an optical filter with adjustable spectrum according to an embodiment of the present invention.

Embodiments of the present invention are discussed in detail below. It will be appreciated, however, that the embodiments provide many applicable concepts that can be implemented in a wide variety of such specific content. The discussed and disclosed embodiments are provided for illustration only, and are not intended to limit the scope of the present invention. All embodiments of the present invention disclose various features, which may be implemented individually or in combination as desired.

In addition, "first", "second", .

In the application of some optical filters, the optical filters are usually replaced according to the requirements, so as to achieve different filtering effects. However, the replacement of filters often causes inconvenience in use, for example, it is necessary to carry filters of different colors or types or to use a replacement mechanism for replacement. In view of this, the embodiments of the present invention provide an optical filter with adjustable spectrum, which can provide light transmission spectra in different wavelength ranges without changing the optical filter, thereby solving the above problems.

Please refer to FIG. 1 . FIG. 1 illustrates an optical filter with adjustable spectrum according to an embodiment of the present invention. In this embodiment, the filter 100 may mainly include at least three filters. Among these filters, the spectrum of at least two filters can be adjusted, and at least one filter has a fixed spectrum. In the example shown in FIG. 1 , the filter 100 includes a first filter 110 , a second filter 120 , a third filter 130 , and a fourth filter stacked on each other in the light incident direction D1 140. That is, the first filter 110 is arranged on the second filter 120 , the second filter 120 is arranged on the third filter 130 , and the third filter 130 is arranged on the fourth filter 140 . In this way, after the light enters the filter 100, it will pass through the first filter 110, The second filter 120 , the third filter 130 , and the fourth filter 140 .

In the embodiment in which the optical filter 100 only includes the first optical filter 110 , the second optical filter 120 , and the third optical filter 130 , the first optical filter 110 is a filter whose spectrum can be adjusted. For example, the average refractive index of the first filter 110 can be changed by applying energy, so as to change the transmission spectrum of the first filter 110 . In some exemplary examples, the refractive index of the first filter 110 can be changed by applying a voltage. In some examples, the first optical filter 110 may include different material layers, eg, including alternately stacked first material layers and second material layers. For example, when fabricating the first optical filter 110 , the first material layer and the second material layer can be sequentially deposited on the glass substrate to form an alternately stacked structure. The first material layer is a material layer whose refractive index cannot be changed, and the second material layer is a material layer whose refractive index can be changed by applying a voltage.

With such a structural design, the average refractive index of the first filter 110 can be changed by applying a voltage. For example, if the original refractive index of the second material layer is different from that of the first material layer, the refractive index of the second material layer can be changed to be the same as the refractive index of the first material layer by applying a voltage.

Please refer to FIG. 2 . FIG. 2 is a graph showing the refractive index of the second material layer of an optical filter of an optical filter with adjustable spectrum according to an embodiment of the present invention when different voltages are applied. In this example, the refractive index of the first material layer for light in a specific wavelength range is the refractive index n ₁ . When the first voltage V ₁ is applied, for example, the applied voltage is 0V, the original refractive index of the second material layer for the light in the specific wavelength range is the refractive index n ₂ , wherein the refractive index n ₂ is greater than the refractive index n ₁ . Therefore, when the applied voltage is 0V, the light in the specific wavelength range cannot pass through the first filter 110 due to the difference between the refractive index n ₂ of the second material layer and the refractive index n ₁ of the first material layer.

To allow the light in the specific wavelength range to pass through the first filter 110, a second voltage V ₂ can be applied to the first filter 110 to change the refractive index of the second material layer for the light in the specific wavelength range from The refractive index n ₂ is changed to the same refractive index n ₁ as the first material layer, so that the average refractive index of the first filter 110 becomes the refractive index n ₁ . In this way, when the second voltage V ₂ is applied, the first filter 110 has a transmission spectrum that allows light to pass through the specific wavelength range.

In some cases, if the original refractive index of the second material layer is the same as that of the first material layer, the refractive index of the second material layer can also be changed to be different from the refractive index of the first material layer by applying a voltage, Thereby, the transmission spectrum of the first filter 110 is changed. In some other examples, other methods can also be used to change the average refractive index of the first optical filter 110 , such as applying a magnetic field, sound waves, pressure, or thermal energy.

In some examples, the first optical filter 110 has at least three material layers, that is, the first optical filter 110 has at least two first material layers and at least one second material layer. In some other examples, the first filter 110 may include a greater number of first material layers and second material layers. The number of the first material layer and the second material layer included in the first optical filter 110 can be determined according to the accuracy of the required transmission spectrum. For example, if the first filter 110 needs to accurately filter out light in a specific wavelength range, the first filter 110 needs to include more The number of stacked material layers, whereby the formed transmission spectrum can more clearly define the end wavelengths of the light in the wavelength range to be filtered.

The thicknesses of the first material layer and the second material layer can be adjusted according to requirements. For example, various thicknesses of the first material layer and the second material layer can be deposited according to the wavelength range of the transmission spectrum to be formed by the first optical filter 110 . In this way, a filter can be formed that allows light in different wavelength ranges to pass through or blocks the transmission spectrum of light in different wavelength ranges.

Through the structural design of the alternately stacked first material layers and second material layers with different thicknesses and numbers, the average refractive index of the first optical filter 110 can be changed by adjusting the applied voltage, and then the first material layer 110 can be changed. The transmission spectrum of the filter 110 . For example, when the applied voltage is 0V, the first filter 110 can block the light of the first wavelength range from passing through; and when different voltages are applied, the first filter 110 can pass the light of all wavelength ranges pass.

The second filter 120 is also a filter with adjustable spectrum. Similar to the first filter 110 , the second filter 120 may include different material layers, such as alternately stacked first material layers and second material layers of different thicknesses. Therefore, the refractive index of the second material layer of the second filter 120 can also be changed by applying a voltage, thereby changing the transmission spectrum of the second filter 120 . The difference from the first filter 110 is that when the applied voltage is 0V, the second filter 120 blocks the passage of light in the second wavelength range. The second wavelength range light and the first wavelength range light have different wavelengths.

The third filter 130 is a filter with a fixed spectrum, such as a bandpass filter. For example, the third filter 130 can be a dual bandpass filter, And it has a transmission spectrum that allows the light of the first wavelength range and the light of the second wavelength range to pass, and blocks the light of other wavelength ranges to pass through. The third filter 130 can be made of a material whose refractive index does not change with voltage. In this way, the optical filter 100 can achieve various spectral outputs by using the first optical filter 110 and the second optical filter 120 with adjustable transmission spectrum, and the third optical filter 130 with fixed transmission spectrum.

In the embodiment in which the optical filter 100 further includes a fourth optical filter 140, the fourth optical filter 140 can also be a filter with adjustable spectrum. Similar to the first filter 110 and the second filter 120 described above, the fourth filter 140 may also include alternately stacked first material layers and second material layers with different thicknesses. Therefore, the refractive index of the second material layer of the fourth filter 140 can also be changed by adjusting the applied voltage, and the transmission spectrum of the fourth filter 140 can be changed. The difference from the first filter 110 and the second filter 120 is that when the applied voltage is 0V, the fourth filter 140 blocks the passage of light in the third wavelength range. The third wavelength range light and the first wavelength range light and the second wavelength range light have different wavelengths. In such an example, the third filter 130 has the function of allowing the light of the first wavelength range, the light of the second wavelength range, and the light of the third wavelength range to pass, and blocking the light of other wavelength ranges from passing through. spectrum. At this time, the third filter 130 is a triple bandpass filter.

Accordingly, the filter 100 may include any number of spectrally tunable filters and a fixed spectral filter. In this way, the optical filter 100 can filter out light in different wavelength ranges through different combinations of filters according to requirements.

In some examples, the first filter 110 , the second filter 120 , and the fourth filter 140 respectively include alternately stacked first material layers and second material layers with different layers and/or different thicknesses. In some demonstrative examples, the first material layer includes silicon oxynitride (SiN _x O _y ), and the second material layer includes liquid crystal material (LC-H). The first material layer is a material layer with an invariable refractive index, and the second material layer is a material layer with a variable refractive index.

The following is an example of the optical filter 100 including the first optical filter 110 , the second optical filter 120 , and the third optical filter 130 , to illustrate the spectral regulation design of the optical filter 100 . Please refer to FIGS. 3A, 3B, 4A, 4B, and 5. FIGS. 3A and 3B respectively illustrate transmission spectra of the first optical filter according to an embodiment of the present invention when different voltages are applied, 4A and 4B respectively illustrate transmission spectra of the second filter according to an embodiment of the present invention when different voltages are applied, and FIG. 5 illustrates the third filter according to an embodiment of the present invention The transmission spectrum of the film.

As shown in FIG. 3A , when the applied voltage is 0V, the first filter 110 can block the light of the first wavelength range λ ₁ from passing through, and can allow the light of other wavelength ranges to pass through. On the other hand, as shown in FIG. 3B, when a voltage of about 3V is applied, the refractive index of the second material layer in the first filter 110 is changed to be the same as that of the first material layer due to the action of the voltage, so that the A filter 110 allows light to pass through all wavelength bands. In some embodiments, the first wavelength range light λ ₁ is light in the infrared wavelength range from about 920 nm to about 940 nm.

As shown in FIG. 4A , when the applied voltage is 0V, the second filter 120 can block the second wavelength range light λ ₂ from passing through, and allow other wavelength range light to pass through. On the other hand, as shown in FIG. 4B, when a voltage of about 3V is applied, the refractive index of the second material layer in the second filter 120 is changed to be the same as that of the first material layer due to the action of the voltage, so that the first material layer is changed. The second filter 120 can pass light in all wavelength bands. In some embodiments, the second wavelength range light λ ₂ is light in the visible wavelength range from about 400 nm to about 640 nm.

As shown in FIG. 5 , in order to match the wavelength range light that the first filter 110 and the second filter 120 can filter, the third filter 130 has a wavelength range that allows the first wavelength range light λ ₁ and the second The wavelength band light λ ₂ passes through and blocks the transmission spectrum through which other wavelength band light passes.

Please refer to FIG. 6 . FIG. 6 illustrates the transmission spectrum of the optical filter with adjustable spectrum according to an embodiment of the present invention. In this embodiment, if the filter 100 wants to filter out the second wavelength range light λ ₂ as shown in FIG. A voltage of 0V is applied, and a voltage of about 3V is applied to the second filter 120 . In this way, the first filter 110 can exhibit the transmission spectrum as shown in FIG. 3A , and the second filter 120 can exhibit the transmission spectrum as shown in FIG. 4B .

In this case, when the light passes through the first filter 110 along the light incident direction D1 , the first wavelength range light λ ₁ is blocked by the first filter 110 . At this time, since the second filter 120 can allow all wavelength range light to pass, the remaining wavelength range light filtered by the first filter 110 will all pass through the second filter 120 . When the remaining wavelength range light passes through the third filter 130, since the first wavelength range light λ1 has been filtered by the first filter 110, only the _second wavelength range light _λ2 can pass through the first wavelength range light λ2. Three filters 130 . Thereby, the filter 100 can generate a transmission spectrum through which only the second wavelength range light λ ₂ can pass, as shown in FIG. 6 .

Please refer to FIG. 7 . FIG. 7 illustrates the transmission spectrum of the optical filter with adjustable spectrum according to an embodiment of the present invention. In this embodiment, if the filter 100 wants to filter out the light of the first wavelength range λ ₁ as shown in FIG. A voltage of about 3V is applied, and a voltage of 0V is applied to the second filter 120 . Thereby, the first filter 110 can exhibit the transmission spectrum as shown in FIG. 3B , and the second filter 120 can exhibit the transmission spectrum as shown in FIG. 4A .

When the light passes through the first filter 110 along the light incident direction D1 , light in all wavelength ranges will pass through the first filter 110 . When the light passes through the second filter 120 , the second wavelength range light λ ₂ is blocked by the second filter 120 . When the remaining wavelength band light passes through the third filter 130, since the _second wavelength band light λ2 has been blocked by the second filter 120, only the _first wavelength band light λ1 can pass through The third filter 130 . Thereby, the filter 100 can generate a transmission spectrum through which only the first wavelength range light λ ₁ can pass.

By applying different voltages to the first filter 110 and the second filter 120 to change the transmission spectrum, the filter 100 can provide different wavelength ranges without changing the filter. Light penetration spectrum. In this way, the inconvenience caused by replacing the optical filter can be effectively reduced, and the practicality of the optical filter 100 can be improved.

To sum up, one of the advantages of the present invention is that the filter with adjustable spectrum of the present invention includes a filter for changing the filter spectrum as the voltage changes and a filter for fixing the spectrum. The filter spectrum of some of the filters in the filter can be changed by changing the voltage, so the filter can provide light in different wavelength ranges without changing the filter, thereby improving the filter's performance. Convenience and applicability.

The embodiments of the present invention have been disclosed above with examples, but they are not intended to limit the present invention. Those skilled in the art can make various changes, substitutions, and changes without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection shall be determined by the scope of the appended patent application.

100: filter

110: The first filter

120: Second filter

130: Third filter

140: Fourth filter

D1: incoming light direction

Claims (10)

An optical filter with adjustable spectrum, comprising: a first optical filter, a second optical filter, and a third optical filter stacked on each other in a light incident direction, the first optical filter is arranged on On the second filter, the second filter is disposed on the third filter, wherein when a first voltage is applied, the first filter is configured to block light in a first wavelength range Pass, the second filter is configured to block a second wavelength range light from passing through, wherein the first wavelength range light and the second wavelength range light have different wavelengths, when a second voltage is applied, each A first filter and the second filter are configured to pass light of all wavelength bands, and the third filter is configured to pass light of the first wavelength band and light of the second wavelength band pass through, and block the passage of light in other wavelength ranges. The optical filter with adjustable spectrum according to claim 1, wherein the first wavelength range light is an infrared light wavelength range light. The optical filter with adjustable spectrum according to claim 2, wherein the second wavelength range light is a visible light wavelength range light. The optical filter with adjustable spectrum as claimed in claim 1, wherein each of the first optical filter and the second optical filter comprises at least two first material layers and at least one second material layer, the at least two second material layers A material layer is alternately stacked with the at least one second material layer, wherein when the first voltage is applied, the at least one The two first material layers and the at least one second material layer have different refractive indices, and when the second voltage is applied, the at least two first material layers and the at least one second material layer have the same refractive index. The optical filter with adjustable spectrum as claimed in claim 4, wherein each of the at least two first material layers comprises silicon oxynitride. The optical filter with adjustable spectrum according to claim 5, wherein the at least one second material layer comprises a liquid crystal material. The optical filter with adjustable spectrum as claimed in claim 1, wherein the third optical filter is composed of a material whose refractive index does not change with voltage. The optical filter with adjustable spectrum according to claim 1, wherein the first voltage is 0V. The optical filter with adjustable spectrum as claimed in claim 8, wherein the second voltage is 3V. An optical filter with adjustable spectrum, comprising: a first optical filter, a second optical filter, a third optical filter, and a fourth optical filter stacked on each other in a light incident direction, the The first filter is arranged on the second filter, the second filter is arranged on the third filter, The third filter is disposed on the fourth filter, wherein when a first voltage is applied, the first filter is configured to block the passage of light in a first wavelength range, and the second filter The fourth filter is configured to block the passage of light of a second wavelength range, the fourth filter is configured to block the passage of light of a third wavelength range, wherein the light of the first wavelength range, the light of the second wavelength range, and the light of the first wavelength range The three wavelength ranges of light all contain different wavelengths. When a second voltage is applied, each of the first filter, the second filter, and the fourth filter is configured to allow all wavelength ranges to pass through. , and the third filter is configured to allow the light of the first wavelength range, the light of the second wavelength range, and the light of the third wavelength range to pass through, and to block the light of other wavelength ranges from passing through.

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