Glass ceramic panel and cooking device having the same

Abstract

The present invention provides a glass ceramic panel and a cooking device having the glass ceramic panel. The glass ceramic panel comprises: a glass ceramic substrate having a smooth upper surface and a protrusion on the lower side; a transparent adhesive layer located below the glass ceramic substrate; and a filter film, the filter film being adhered to the glass ceramic substrate through the adhesive layer. The adhesive layer is pressed into the valleys formed between the protrusions, so that light from below the glass ceramic panel can be transmitted from the glass ceramic panel to the upper side thereof uniformly and without color shift. In this case, light viewed from the upper side of the glass ceramic panel will not produce color shift.

Description

Technical Field

[0001] The invention relates to a glass ceramic panel and a cooking device having the glass ceramic panel. The glass ceramic panel is provided with a light filtering sheet to avoid or at least reduce the color shift or distortion generated by the light emitted from below the glass ceramic panel. Background Art

[0002] Black glass ceramic cooking tops, e.g. CERAN A protrusion is provided on its lower surface side to increase the damage resistance of the cooking panel.

[0003] During the production and installation of the glass ceramic cooking panel, it only contacts other materials, such as oven brackets, conveyor rollers, packaging, etc., at the top of the protrusions, rather than in the valleys between the protrusions. Therefore, possible damage, such as scratches caused by contact with hard materials, is limited to the top of the protrusions. The tops of these protrusions form only a small part of the entire surface of the glass ceramic panel. Therefore, the overall mechanical stability of the glass ceramic panel is enhanced by the protrusions, because most of the surface area of ​​the display panel is free of defects such as scratches. Generally speaking, the glass ceramic panel is 4 mm thick, the height of the protrusions is about 0.5 mm, and the lateral distance between two adjacent protrusions is about 2 mm. The protrusions are produced during the hot forming of the crystallizable pre-glass ("green glass") by rolling with a roller having protrusions.

[0004] At the beginning of the production process, the height of the shape of the roller profile is set to 0.5 mm. During the production process, the roller profile wears due to the interaction between the roller and the hot glass. This causes the height of the protrusion to decrease. When the protrusion height reaches 0.1 mm, the roller is replaced by a "new" roller, regenerating a 0.5 mm high protrusion. The glass ceramic cooking panel has a visible light transmittance (Y value in the CIExyY (1931) color space, also called brightness) of approximately Y = 1.5 to 2%.

[0005] Nowadays, it is very desirable to create a user interface on the glass ceramic panel itself. Such a user interface comprises an input device and a display device. The input device is usually a touch sensor. The display device for the glass ceramic panel is usually an LED 7-segment display. The display device shows the current heating level of the glass ceramic cooking panel in operation. Both the input device and the display device are placed under the glass ceramic panel. The input device senses touch through the glass ceramic panel. The display device emits light, which is transmitted through the panel and can therefore be seen by the user on the other side of the panel.

[0006] Specifically, in the prior art, Figure 1 As shown, the cooking device 100 generally includes a heating area 101, a display area 102 and a touch area 103 in its top view. Figure 2 As can be seen, the cooking device 100 generally includes a heating element 1, a glass ceramic panel 2, a touch sensor 3, and a 7-segment light-emitting display element 4. Among them, the touch sensor 3 and the light-emitting display element 4 are placed below the glass ceramic panel 2. Generally, the light-emitting display element 4 is an LED. In addition, the glass ceramic panel 2 includes a smooth upper surface 21 and a protrusion 22 located on the lower surface side, so that the glass ceramic panel 2 includes a plurality of thick portions 23 and thin portions 24. In addition, the protrusion 22 is in contact with the touch sensor 3 and the light-emitting display element 4 below. In this case, the light emitted by the light-emitting display element 4 passes through the glass ceramic panel 2, namely the thick portion 23 and the thin portion 24, and the transmittance of the light is different when passing through the thick portion 23 and the thin portion 24, and since a valley is formed between the protrusion 22 and the thin portion 24, the light will be refracted at the protrusion 22, such as Figure 2 In this case, the display mark viewed from the upper side of the panel will be distorted or have color aberration, so the protrusions 22 act like a set of lenses, distorting the image of the 7-segment display element.

[0007] Red LED lighting under black glass ceramic cooking panels is well known. Nowadays, it is desirable to use LEDs with other colors besides red to produce specific lighting effects. It is particularly desirable to use white LEDs or blue LEDs. The problem with white and blue LEDs is that the transmission spectrum of black glass ceramic cooking panels varies strongly in the visible spectrum. Conventional cooking panels have a high transmittance in the red part of the spectrum, while they have a low transmittance in the blue part of the spectrum. Therefore, the light emitted by the white LED will appear yellow instead of white after being transmitted through the cooking panel. Summary of the invention

[0008] An object of the present invention is to provide a glass ceramic panel and a cooking device having the same, wherein light emitted from the bottom of the glass ceramic panel can be transmitted from the bottom of the glass ceramic panel to the top side uniformly and without color shift.

[0009] A glass ceramic panel for a cooking device according to the present invention comprises:

[0010] A glass ceramic substrate having a smooth upper surface and a protrusion on a lower side;

[0011] a transparent adhesive layer disposed below the glass-ceramic substrate;

[0012] A filter film, wherein the filter film is adhered to the glass ceramic substrate through the adhesive layer;

[0013] The adhesive layer is pressed into the valleys formed between the protrusions, so that light from below the glass ceramic panel can be transmitted from the glass ceramic panel to the upper side thereof evenly and without color shift.

[0014] In a preferred embodiment of the present invention, the bonding strength between the glass ceramic substrate and the filter film is determined by a quality factor FOM, which is FOM=temperature*pressure / speed, and is in the range of 24-3700°C*bar / (m / min). Preferably, the quality factor FOM is in the range of 75-1500°C*bar / (m / min), more preferably in the range of 400-800°C*bar / (m / min), in which case the best optical display capability is given. In addition, it is also preferred as required that the quality factor FOM is in the range of 1800-3000°C*bar / (m / min), more preferably in the range of 2100-2500°C*bar / (m / min), in which case the best adhesion is provided between the glass ceramic substrate and the filter film.

[0015] In a preferred embodiment of the present invention, the filter film is a color compensation filter film.

[0016] In another preferred embodiment of the present invention, the thickness of the adhesive layer is half of the height of the protrusion.

[0017] In another preferred embodiment according to the present invention, the height of the protrusion is 0.5 mm, and the thickness of the adhesive base layer is in the range of 0.05-0.25 mm.

[0018] In another preferred embodiment of the present invention, the thickness of the glass ceramic substrate is 4 mm, and the thickness of the filter film and the adhesive layer is less than 0.35 mm.

[0019] Another aspect of the present invention also provides a cooking device, comprising:

[0020] The glass ceramic panel of the present invention; and

[0021] The light-emitting display element is located below the glass ceramic panel, and the light emitted from the light-emitting display element can be transmitted from the glass ceramic panel to the upper side thereof uniformly and without color shift.

[0022] In a preferred embodiment of the present invention, the cooking device further comprises a touch sensor located below the glass ceramic panel.

[0023] In another preferred embodiment of the present invention, the light-emitting display element is a 7-segment LED.

[0024] In the technical solution according to the present invention, since there is a filter film for color compensation under the glass ceramic panel, the light emitted from the light-emitting display element under the glass ceramic panel can obtain color compensation of the filter film without color shift. In addition, the refractive index of the adhesive layer according to the present invention matches the refractive index of the glass ceramic, so that the light-emitting display element has optimal visibility.

[0025] Furthermore, more importantly, since the adhesive layer protrudes into the valleys formed between the protrusions, it can improve distortion or chromatic aberration caused by refraction caused by the protrusions, so that light can be uniformly transmitted from the glass ceramic panel to its upper side.

[0026] Another aspect of the present invention provides a method for manufacturing the above-mentioned glass-ceramic panel, which comprises the following steps:

[0027] Step S1: providing a glass ceramic substrate and a filter membrane, wherein the glass ceramic substrate has a protrusion on the lower surface side thereof, and the filter membrane comprises a filter membrane, an adhesive layer and a release paper;

[0028] Step S3: removing the release paper;

[0029] Step S4: preliminarily bonding the adhesive layer of the filter membrane to the glass ceramic substrate;

[0030] Step S5: laminating the filter membrane and the glass ceramic substrate so that the adhesive layer is pressed into the valleys formed between the protrusions to form the glass ceramic panel.

[0031] In a preferred embodiment of the present invention, before step S1, the method further comprises step S01: measuring the height of the protrusion, and then in step S1, selecting the filter film so that the thickness of the adhesive layer is half of the height of the protrusion.

[0032] In another preferred embodiment of the present invention, the size of the release paper is slightly larger than the filter film and the adhesive layer to facilitate removal of the release paper.

[0033] In another preferred embodiment of the present invention, in step S5, the filter membrane and the glass ceramic substrate are laminated by a hot lamination process. In the hot lamination process, the glass ceramic substrate and the filter membrane are first heated to a temperature in the range of 150°C-200°C. In addition, the pressure roller is also heated to a temperature in the range of 150°C-200°C, and then the glass ceramic substrate and the filter membrane are moved through two opposing pressure rollers at a speed of 0.5-1.5 m / min, and the two pressure rollers apply a pressure of 1-3 bar to the glass ceramic substrate and the filter membrane. According to the method of the present invention, the highest bonding strength is achieved by high temperature, low speed and high pressure without damaging the glass ceramic substrate and the filter membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a top view of a cooking device according to the prior art.

[0035] Figure 2 It is a schematic cross-sectional block diagram of the structure of a cooking device according to the prior art.

[0036] Figure 3 It is a schematic diagram of light transmission of a glass ceramic panel according to the prior art.

[0037] Figure 4 is a schematic cross-sectional block diagram of the structure of a cooking device according to the present invention.

[0038] Figure 5 Schematic diagram of light transmission of the glass ceramic panel according to the present invention.

[0039] Figure 6 It is a comparison diagram of the display effects of the glass-ceramic panel according to the prior art and the present invention.

[0040] Figure 7 The invention relates to a method for adhering a filter film to a glass ceramic substrate.

[0041] Figure 8 Schematic diagram of the filter membrane provided according to the present invention. DETAILED DESCRIPTION

[0042] like Figure 4As shown, the cooking device according to the present invention includes a heating element 10, a glass ceramic panel 20, a touch sensor 30, and a 7-segment light-emitting display element 40. The touch sensor 30 and the light-emitting display element 40 are placed below the glass ceramic panel 2. The light-emitting display element 40 is preferably a 7-segment LED, which can be a dot-shaped or line-shaped LED, and the display pattern is preferably text, numbers or symbols. In addition, the glass ceramic panel 20 includes a glass ceramic substrate 200, which has a smooth upper surface 201 and protrusions 202 located on the lower surface side, so that the glass ceramic substrate 200 includes valleys 203 located between the protrusions. In addition, as shown Figure 5 As shown, the glass ceramic panel 20 according to the present invention includes a filter film 205 adhered to the lower side of the glass ceramic substrate 200 for color compensation. The filter film 205 is adhered to the protrusions 202 on the lower surface side of the glass ceramic substrate 200 through an adhesive layer 206 and protrudes into the valleys formed between the protrusions 202.

[0043] The following describes in detail how to adhere the filter film 205 to the protrusion 202 on the lower surface side of the glass ceramic substrate 200, that is, the method for manufacturing the glass ceramic panel 2 according to the present invention. Figure 7 shown.

[0044] First, in step S1, a sheet-shaped filter film 25, such as a color compensation film, is provided. Figure 8 As shown, the filter membrane 25 is composed of a filter membrane 205, an adhesive layer 206 and a release paper 207, wherein the filter membrane 205 and the adhesive layer 206 are usually integrated, and the other side of the adhesive layer 206 has a release paper 207, and the release paper 207 is a sheet material that is at least slightly larger than the filter membrane 205 in size.

[0045] Then, in step S2, a double-sided tape is adhered to the side of the filter film 205 opposite to the release paper 207, wherein the adhesive force between the double-sided tape and the filter film 205 must be greater than the adhesive force between the adhesive layer 206 and the release paper. According to the present invention, any double-sided tape with sufficiently strong adhesive force can be used, such as double-sided tape from TESA or 3M.

[0046] In step S3, the double-sided tape is pulled to remove the filter film 205 from the release paper 207. Since the adhesive force between the double-sided tape and the filter film 205 is greater than the adhesive force between the adhesive layer 206 and the release paper 207, the filter film 205 and the adhesive layer 206 are easily separated from the release paper 207 by simply pulling the double-sided tape.

[0047] In step S4, the filter film 205 and the adhesive layer 206 are transferred to the glass ceramic substrate 200 and aligned to the desired position. The filter film 205 and the adhesive layer 206 are placed on the glass ceramic substrate 200 so that the adhesive layer 206 of the filter film 25 faces the protrusion 202 of the glass ceramic substrate 200, and the adhesive layer 206 on the filter film 25 contacts the protrusion 202 of the glass ceramic substrate 200. Then, the filter film 25 is pressed onto the glass ceramic substrate 200 to cause preliminary bonding between the filter film 25 and the glass ceramic substrate 200.

[0048] Then, in step S5, a final bond is formed between the adhesive layer 206 of the filter membrane 25 and the glass ceramic substrate 200 by a heat lamination process. Specifically, the glass ceramic substrate 200 and the filter membrane 25 are first heated to at least 150° C. and not more than 200° C. In this temperature range, the adhesive layer 206 will soften, but will not damage the filter membrane 205 and the adhesive layer 206. If the glass ceramic substrate 200, the filter membrane 205 and the adhesive layer 206 are heated to more than 200° C., the filter membrane 205 and the adhesive layer 206 thereon may be damaged. In this case, the glass ceramic substrate 200 with the filter membrane 205 moves through two pressing rollers at a speed of 0.5-1.5 m / min, wherein the two pressing rollers are preferably heated to 150° C.-200° C., preferably heated to the same temperature as the glass ceramic substrate 200 and the filter membrane 205, to enhance the effect of the heat lamination process. The pressure applied to the glass ceramic substrate 200 and the filter film 205 by the pressure roller can be adjusted between 1-3 bar. In the technical solution according to the present invention, high temperature, low speed and high pressure can achieve the highest bonding strength without damaging the glass ceramic substrate 200 and the filter film 205. Through this combination of temperature and pressure, the adhesive layer 206 becomes soft and can be pressed into the valleys between the protrusions 202 without generating bubbles or other defects, so the optical transmission performance of the glass ceramic panel 2 is not significantly affected.

[0049] In addition, the index to measure the bonding strength is the quality factor FOM, which can be calculated as follows:

[0050] FOM = temperature*pressure / speed.

[0051] In the technical solution according to the present invention, FOM is in the range of 24-3700°C*bar / (m / min). In a preferred embodiment, FOM is in the range of 75-1500°C*bar / (m / min), in particular in the range of 400-800°C*bar / (m / min). In this case, the best optical display performance is given. In another preferred embodiment, FOM is in the range of 1800-3000°C*bar / (m / min), in particular in the range of 2100-2500°C*bar / (m / min). In this case, the best adhesion is provided, in particular, the best adhesion can be provided at high temperatures throughout the entire life cycle of the glass ceramic panel.

[0052] The inventors have found that the best results can be achieved if the thickness of the adhesive layer 206 is about half the height of the protrusion 202. Therefore, the thickness of the adhesive layer 206 is in the range of 0.05-0.25 mm. If the thickness of the adhesive layer 206 is less than 0.05 mm, the bonding force is not strong enough. In addition, the total thickness of the adhesive layer 206 and the filter film 205 does not exceed 0.35 mm before bonding. Generally speaking, the total thickness of the adhesive layer 206 and the filter film 205 becomes smaller after bonding. If this total thickness is greater, the sensitivity of the touch sensor under the cooking panel will decrease because the distance between the touch sensor and the touch surface increases. This is because the glass ceramic panel is usually 4 mm thick. Adding a layer of about 0.4 mm to the total thickness of the glass ceramic panel increases the distance between the upper touch surface and the lower touch sensor by about 10%, which reduces the sensitivity. As the distance increases, the sensitivity decreases linearly. Thus, the sensitivity will decrease by 10% or more if the distance increases by about 10%.

[0053] In addition, in a preferred embodiment, the filter film 205 can have an adhesive layer 206 of different thicknesses. In an optional step S01 before step S1, it is preferred to use a white light interferometer to measure the height of the protrusion, and select a filter film 25 with an adhesive layer 206 of appropriate thickness based on the measured protrusion height. This optional step S01 can be performed in two different ways. One way is to select the thickness of the adhesive layer 206 to be half the height of the protrusion 202 to obtain the best adhesion. Another way is to select the thickness of the adhesive layer 206 so that the total thickness of the glass ceramic panel 2 including the protrusion 202, the adhesive layer 206 and the filter film 205 is constant throughout the production process. In this embodiment, the wear of the roller used for molding can be compensated. In this way, the distance between the touch surface on the upper side of the glass ceramic panel 2 and the touch sensor on the lower side remains constant, which provides the best touch effect for user input.

[0054] According to one embodiment of the present invention, the adhesive is highly transparent, does not absorb light and does not scatter light, so that the best display performance can be obtained. For example, the adhesive can be an acrylate-based adhesive, and does not absorb or spread additives such as pigments, colorants or particles, and more particularly, does not contain TiO 2 The adhesive layer according to the present invention is resistant to high temperatures and does not chemically crack or turn yellow at high temperatures.

[0055] According to the present invention, the filter film 205 can be a color compensation filter film. In addition, preferably, the color compensation filter film can be volume-colored, that is, it is uniformly colored throughout its entire volume. Optionally, the color filter film can also be surface-colored by applying a colored coating. Volume-colored filters are more scratch-resistant and high-temperature-resistant, while surface-colored filters are cheaper. If such a colored filter film is combined with an LED that (almost) emits monochromatic light (for example, blue), the color of the light emitted by the LED will not be changed by the filter film. Only in the case of a multi-color light source, such as a white LED, the color of the light emitted will be changed by the color compensation filter film. Figure 5-6 However, in this case, the filter film reduces the visibility of the LED through the glass ceramic panel, which improves the "invisible display".

[0056] According to the present invention, the bonding between the filter film 205 and the glass ceramic substrate 202 is as free of bubbles as possible. 2 It is acceptable for the filter film to contain less than 10 bubbles with a size less than 0.5 mm or preferably less than 0.1 mm.

[0057] In addition, the refractive index of the adhesive layer according to the present invention is matched to the refractive index of the glass ceramic to provide the display with optimal visibility. Preferably, the refractive index of the adhesive layer is 1.5-1.65, preferably 1.55-1.6.

Claims

1. A glass ceramic panel for a cooking device, comprising: A glass ceramic substrate having a smooth upper surface and a protrusion on a lower side; a transparent adhesive layer disposed below the glass-ceramic substrate; A filter film, wherein the filter film is adhered to the glass ceramic substrate through the adhesive layer; It is characterized in that the adhesive layer is pressed into the valleys formed between the protrusions, so that the light from below the glass-ceramic panel can be transmitted from the glass-ceramic panel to its upper side evenly and without color shift, wherein the thickness of the adhesive layer is half of the height of the protrusions, wherein the bonding strength between the glass-ceramic substrate and the filter film is determined by the quality factor FOM, which is FOM = temperature * pressure / speed, which is in the range of 24-3700℃*bar / (m / min).

2. The glass ceramic panel for a cooking device according to claim 1, characterized in that: The figure of merit FOM is in the range of 75-1500° C.*bar / (m / min).

3. The glass ceramic panel for a cooking device according to claim 1, characterized in that: The figure of merit FOM is in the range of 400-800° C.*bar / (m / min).

4. The glass ceramic panel for a cooking device according to claim 1, characterized in that: The figure of merit FOM is in the range of 1800-3000° C.*bar / (m / min).

5. The glass ceramic panel for a cooking device according to claim 1, characterized in that: The figure of merit FOM is in the range of 2100-2500° C.*bar / (m / min).

6. The glass ceramic panel for a cooking device according to claim 1, characterized in that: The filter film is a color compensation filter film.

7. The glass ceramic panel for a cooking device according to claim 1, characterized in that: The height of the protrusions is 0.5 mm, and the thickness of the adhesive base layer is in the range of 0.05-0.25 mm.

8. The glass ceramic panel for a cooking device according to claim 1, characterized in that: The thickness of the glass ceramic substrate is 4 mm, and the thickness of the filter film and the adhesive layer is less than 0.35 mm.

9. A cooking device, characterized in that: include: A glass ceramic panel for a cooking device according to any one of claims 1 to 8; as well as The light-emitting display element is located below the glass ceramic panel, and the light emitted from the light-emitting display element can be transmitted from the glass ceramic panel to the upper side thereof uniformly and without color shift.

10. The cooking device according to claim 9, characterized in that: Also included is a touch sensor located below the glass ceramic panel.

11. The cooking device according to claim 9, characterized in that: The light emitting display element is an LED.

12. The cooking device according to claim 9, characterized in that: The light-emitting display element is a 7-segment LED.

13. The cooking device according to claim 9, characterized in that: The light-emitting display element is a dot-shaped LED.

14. The cooking device according to claim 9, characterized in that The light-emitting display element is a linear LED.

15. The cooking device according to claim 9, characterized in that The light-emitting display element is an LED, and its display pattern is text, numbers or symbols.

16. A method for manufacturing a glass ceramic panel according to any one of claims 1 to 8, comprising the following steps: Step S1: providing a glass ceramic substrate and a filter membrane, wherein the glass ceramic substrate has a protrusion on its lower surface side, and the filter membrane comprises a filter membrane, an adhesive layer and a release paper, wherein: The thickness of the adhesive layer is half the height of the protrusion; Step S3: removing the release paper; Step S4: preliminarily bonding the adhesive layer of the filter membrane to the glass ceramic substrate; Step S5: Laminating the filter membrane and the glass-ceramic substrate so that the adhesive layer is pressed into the valleys formed between the protrusions to form the glass-ceramic panel, wherein in the lamination process, the glass-ceramic substrate and the filter membrane are first heated to a temperature in the range of 150°C-200°C, and the glass-ceramic substrate and the filter membrane are moved through two opposing pressure rollers at a speed of 0.5-1.5 m / min, and the two pressure rollers apply a pressure of between 1-3 bar to the glass-ceramic substrate and the filter membrane.

17. The method according to claim 16, characterized in that Before the step S1, the method further comprises a step S01: measuring the height of the protrusion, and then in the step S1, selecting the filter film so that the thickness of the adhesive layer is half of the height of the protrusion.

18. The method according to claim 16, characterized in that The size of the release paper is slightly larger than the filter film and the adhesive layer, so as to facilitate the removal of the release paper.

19. The method according to claim 16, characterized in that In the step S5, the filter membrane and the glass ceramic substrate are laminated by a thermal lamination process.

20. The method of claim 16, wherein the press roll is heated to a temperature in the range of 150°C to 200°C.

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