Method for manufacturing display device for automobiles, display panel for automobiles, and display device for automobiles

Abstract

[Problem] To provide a display panel for automobiles with which it is possible to reduce leakage of light without compromising the strength and aesthetic appearance of the display panel for automobiles and without generating abnormal sound in the display panel for automobiles, and a display device for automobiles that comprises the display panel for automobiles. [Solution] In a groove formation step, a groove 23 is formed between display areas AR11, AR12 for performing display with light transmitted from the back side BS to the front side FS of a transparent resin molded body 21 and an end part 21E of the transparent resin molded body 21, and / or between the mutually adjacent display areas AR11, AR12, by cutting processing using computer numerical control along a prescribed shape so as to leave a thickness TH1 in a prescribed range. In a filling body formation step, the groove is filled with a colored resin that blocks light traveling in the transparent resin molded body 21, and a colored resin filling body 22 is formed in the groove.

Description

Manufacturing method for display device for automobile, display panel for automobile, and display device for automobile

[0001] The present invention relates to a method for manufacturing an automotive display device, an automotive display panel, and an automotive display device.

[0002] The instrument panel of an automobile is provided with a display device, such as a navigation system display as described in Patent Document 1 (Japanese Patent No. 7125713) or an icon on a heater control panel.

[0003] Patent No. 7125713

[0004] In automotive display devices, light propagates through the transparent resin molded body of an automotive display panel or heater control panel, and light may leak from, for example, the edge of the transparent resin molded body. If light leaks from the edge of an automotive display panel or heater control panel inside a vehicle at night, the leaked light is very noticeable. To reduce light leakage from the edge of such a transparent resin molded body, a light-blocking device may be provided at the location where the light leaks. However, if the shape of the transparent resin molded body is made complex to provide a light-blocking device, the surface of the transparent resin molded body of the automotive display panel may be marred by sink marks or other defects after molding, which may detract from the aesthetic appearance. If the aesthetic appearance is marred by defects in the surface of the transparent resin molded body, the automotive display panel may be rejected because it is located directly in front of the driver and passengers. Furthermore, instrument panels are likely to be hit by the driver or passengers in traffic accidents, etc., and automotive display panels placed in instrument panels are expected to contribute to protecting the driver and passengers in emergencies such as accidents. Furthermore, in automotive display panels, it is necessary to suppress the reduction in strength and the generation of abnormal noise caused by parts rubbing against each other.

[0005] An object of the present invention is to provide an automotive display panel that does not reduce the strength and aesthetics of the automotive display panel, does not generate abnormal noise in the automotive display panel, and reduces light leakage, and an automotive display device equipped with such an automotive display panel.

[0006] Several embodiments for solving the problems will be described below. These embodiments can be combined as needed. A manufacturing method for an automotive display device according to a first aspect of the present invention includes an injection molding step, a groove forming step, and a filler forming step. In the injection molding step, a transparent resin molded body having a predetermined shape and transmitting light is injection molded. In the groove forming step, grooves are formed by cutting using computer numerical control along a predetermined shape so as to leave a predetermined thickness between a display area that displays using light transmitted from the back surface to the front surface of the transparent resin molded body and an edge of the transparent resin molded body, and / or between adjacent display areas. In the filler forming step, a colored resin filler is formed in the groove by filling the groove with a colored resin that blocks light traveling through the transparent resin molded body. Because the manufacturing method for an automotive display device according to the first aspect includes the groove forming step and the filler forming step, the groove does not need to be formed by injection molding, thereby preventing sink marks and warping that may occur when the groove is formed. Furthermore, since the grooves are filled with colored resin to form colored resin fillers in the grooves, the transparent resin molding around the grooves is integrated with the colored resin filler, and the transparent resin molding is reinforced by the colored resin filler, which suppresses a decrease in the strength of the automotive display panel due to the formation of the grooves and prevents the generation of abnormal noise in the automotive display panel due to automobile vibrations. The colored resin filler in the grooves can reduce light leakage to the edges of the transparent resin molding and / or into adjacent display areas.

[0007] A method for manufacturing an automotive display device according to a second aspect of the present invention is configured in the method for manufacturing an automotive display device according to the first aspect, wherein the predetermined range is 0.5 mm or more and 2 mm or less, and is equal to or less than half the thickness of the transparent resin molding on both sides of the groove. According to the method for manufacturing an automotive display device according to the second aspect, it is possible to appropriately adjust the reduction in light leakage and the suppression of a decrease in the strength of the automotive display panel.

[0008] A manufacturing method for an automotive display device according to a third aspect of the present invention is the same as the manufacturing method for an automotive display device according to the first or second aspect, except that it includes a thinning step in which the display area of ​​the transparent resin molded body is thinned to a predetermined shape by cutting using computer numerical control. According to the manufacturing method for an automotive display device according to the third aspect, molding is facilitated by eliminating the difficulty of molding due to the fluidity of the resin, as in injection molding. Furthermore, thinning the display area by cutting using computer numerical control eliminates the difficulty of molding due to the fluidity of the resin, and can prevent sink marks and warping in the display area.

[0009] A manufacturing method for an automotive display device according to a fourth aspect of the present invention includes, in the manufacturing method for an automotive display device according to the third aspect, a laminating step of laminating a display using an optically transparent resin or an optically transparent adhesive to a portion of the transparent resin molded body that has been thinned by cutting in the thinning step. According to the manufacturing method for an automotive display device according to the fourth aspect, the visibility of the display can be improved by the optically transparent resin or the optically transparent adhesive that is laminated to the portion of the transparent resin molded body that has been thinned by cutting.

[0010] A manufacturing method for an automotive display device according to a fifth aspect of the present invention is configured such that, in the manufacturing method for an automotive display device according to the fourth aspect, the refractive index of the optical transparent resin or the optical transparent adhesive is equal to or greater than the refractive index of the transparent resin molded body minus 0.1 and equal to or less than the refractive index of the transparent resin molded body plus 0.1. According to the manufacturing method for an automotive display device according to the fifth aspect, by setting the refractive index of the optical transparent resin or the optical transparent adhesive to be equal to or greater than the refractive index of the transparent resin molded body 21 minus 0.1 and equal to or less than the refractive index of the transparent resin molded body 21 plus 0.1, it is possible to improve the visibility of the display compared to when the refractive index is set outside this range.

[0011] According to a sixth aspect of the present invention, an automotive display panel includes a transparent resin molded body having a predetermined shape and a groove formed by cutting along the predetermined shape, the transparent resin molded body being transparent to light, and a colored resin filler formed of a colored resin that blocks light traveling through the transparent resin molded body. The transparent resin molded body has a display area that displays information using light transmitted from the back surface to the front surface. The groove is disposed between the display area and an edge of the transparent resin molded body and / or between adjacent display areas. The thickness of the groove portion of the transparent resin molded body is 0.5 mm to 2 mm, and is half or less the thickness of the transparent resin molded body on both sides of the groove. In the automotive display panel of the sixth aspect, the groove is formed by cutting, thereby preventing sink marks and warping that may occur during groove formation. Furthermore, the colored resin is filled into the groove, and the colored resin filler is formed in the groove. This allows the transparent resin molded body around the groove to be integrated with the colored resin filler, thereby reinforcing the transparent resin molded body with the colored resin filler. This prevents a decrease in the strength of the automotive display panel due to the formation of the groove and prevents abnormal noise from occurring in the automotive display panel due to vehicle vibration. The colored resin filler in the grooves can reduce light leakage to the edges of the transparent resin molded body and / or to adjacent display areas. Furthermore, it is possible to appropriately adjust the reduction in light leakage and the suppression of a decrease in the strength of the automotive display panel. The automotive display panel according to a seventh aspect of the present invention is the automotive display panel of the sixth aspect, wherein the transparent resin molded body is machined to make the display area thinner than the surrounding area. The automotive display panel of the seventh aspect can prevent sink marks and warping from occurring in the display area, thereby providing the display area with a good aesthetic appearance.

[0012] An automotive display device according to an eighth aspect of the present invention comprises a light-transmitting transparent resin molded body having a predetermined shape and a groove formed by cutting along the predetermined shape; a colored resin filler made of a colored resin that fills the groove and blocks light traveling through the transparent resin molded body; and a light source arranged on the back surface of the transparent resin molded body and emitting light that transmits through the transparent resin molded body. The transparent resin molded body has a display area that displays using light transmitted from the back surface to the front surface. The groove is arranged between the display area and an edge of the transparent resin molded body and / or between adjacent display areas. The thickness of the grooved portion of the transparent resin molded body is 0.5 mm or more and 2 mm or less, and is half or less of the thickness of the transparent resin molded body on both sides of the groove. In the automotive display device of the eighth aspect, since the groove is formed by cutting, sink marks and warping during groove formation can be prevented. Furthermore, since the grooves are filled with a colored resin to form a colored resin filler in the grooves, the transparent resin molded body around the grooves is integrated with the colored resin filler, and the transparent resin molded body is reinforced by the colored resin filler. This suppresses a decrease in the strength of the automotive display device due to the formation of the grooves and prevents the generation of abnormal noise in the automotive display device due to vehicle vibration. The colored resin filler in the grooves reduces light leakage to the edges of the transparent resin molded body and / or to adjacent display areas. Furthermore, the reduction in light leakage and the suppression of a decrease in the strength of the automotive display device can be appropriately adjusted. A ninth aspect of the present invention is an automotive display device according to the eighth aspect, wherein the transparent resin molded body has a display area that is made thinner than the surrounding area by cutting. The transparent resin molded body includes an optical transparent resin or an optical transparent adhesive that is bonded to the thin portion of the display area, which displays a display using a light source. The automotive display device of the ninth aspect prevents sink marks and warping in the display area, thereby providing the display area with a good aesthetic appearance. Furthermore, the visibility of the display can be improved by using an optically transparent resin or an optically transparent adhesive that is applied to the portion of the transparent resin molded body that has been thinned by cutting.

[0013] According to the method for manufacturing an automotive display device of the present invention, it is possible to provide an automotive display device that does not reduce the strength and aesthetics of the automotive display panel, does not generate abnormal noise in the automotive display panel, and reduces light leakage in the automotive display panel. The automotive display panel or automotive display device of the present invention can reduce light leakage while preventing the reduction in strength and aesthetics and the generation of abnormal noise.

[0014] FIG. 1 is a schematic front view of an instrument panel for explaining the arrangement of an automotive display device in the instrument panel. FIG. 2 is a perspective view showing an example of the configuration of an automotive display panel according to a first embodiment. FIG. 3 is a cross-sectional view of an automotive display panel cut along line II in FIG. 2. FIG. 4 is a cross-sectional view of an automotive display panel cut along line II-II in FIG. 2. FIG. 5 is a flowchart showing an example of a manufacturing flow of an automotive display device according to the first embodiment. FIG. 6 is a cross-sectional view showing an example of the configuration of an automotive display panel according to a second embodiment. FIG. 7 is a cross-sectional view showing an example of the configuration of an automotive display panel according to a third embodiment. FIG. 8 is a flowchart showing an example of a manufacturing flow of an automotive display device according to the third embodiment. FIG. 9 is a cross-sectional view showing an example of the configuration of an automotive display panel according to a fourth embodiment. FIG. 10 is a cross-sectional view showing an example of the configuration of an automotive display panel according to a fifth embodiment.

[0015] First Embodiment (1) Configuration of an Automotive Display Device FIG. 1 shows an instrument panel 10 of an automobile. Meters such as a speedometer 11 are installed on the instrument panel 10. The instrument panel 10 also includes a dashboard 12. A steering wheel 90 is disposed in front of the instrument panel 10. An automotive display panel 20 is disposed in the center of the instrument panel 10. The automotive display panel 20 is, for example, a component of a navigation system. A heater control panel 30 is disposed below the automotive display panel 20. When controlling air conditioning, the term "air conditioning control panel" may be used instead of the term "heater control panel." The heater control panel 30 displays, for example, a temperature setting icon, a heater symbol, a mode switching icon, and a power icon. The temperature setting icon is, for example, an icon showing a number or an arrow indicating a temperature. The heater symbol is a symbol represented by a wavy line design. The heater symbol indicates, for example, that the heater is operating. The mode switch icon indicates the mode of the heater (heating, cooling, fan), and the power icon indicates whether the heater is powered on or off.

[0016] (1-1) Automotive Display Panel An example of an automotive display panel 20 is shown in FIG. 2. The automotive display panel 20 includes a transparent resin molded body 21 and a colored resin filler 22, as shown in FIGS. 3 and 4. FIG. 3 shows a cross-sectional view taken along line II in FIG. 2, and FIG. 4 shows a cross-sectional view taken along line II-II in FIG. 2. A trapezoidal transparent first display area AR11, which is included in the transparent resin molded body 21, is located in the center of the automotive display panel 20 when viewed from the front. Approximately rectangular second and third display areas AR12 and AR13 are located below the first display area AR11. An opening 25, in which, for example, a knob is located, is located between the second and third display areas AR12 and AR13. When viewed from the front, a light-shielding area AR2 is located around the display areas AR11, AR12, and AR13 to block light. The transparent resin molding 21 has a predetermined shape. Here, the predetermined shape is a rectangle when viewed from the front, with a cross section curved in an arch shape and an opening 25. The transparent resin molding 21 has a groove 23 formed by cutting. The groove 23 follows the predetermined shape of the transparent resin molding 21. In other words, the groove 23 shown in FIGS. 3 and 4 is curved in an arch shape along the surface of the transparent resin molding 21, which is curved in an arch shape. Here, the groove 23 follows a simple arch-shaped shape, but the predetermined shape along which the groove 23 follows may be a complex three-dimensional shape combining more curves and surfaces than a simple basic shape such as a flat plate and an arch-shaped shape. The transparent resin molding 21 is made of a transparent resin and transmits light. The transparent resin molding 21 may be translucent.

[0017] The colored resin filler 22 is made of a colored resin filled in the groove 23. The colored resin filler 22 made of a colored resin can block light traveling through the transparent resin molded body 21. Such colored resin filler 22 is arranged along the predetermined shape of the transparent resin molded body 21, thereby reducing light leaking from the end 21E of the transparent resin molded body 21. Because the colored resin filler 22 fills the groove 23, it is firmly bonded to the transparent resin molded body 21. In other words, the colored resin filler 22 is integrated with the transparent resin molded body 21. Because the colored resin filler 22 and the transparent resin molded body 21 are integrated, even if stress is applied to the transparent resin molded body 21 due to, for example, automobile vibration, no displacement occurs between the colored resin filler 22 and the transparent resin molded body 21, thereby preventing the generation of abnormal noises associated with automobile vibration. Furthermore, by distributing stress between the colored resin filler 22 and the transparent resin molded body 21, stress does not concentrate in the portion of the transparent resin molded body 21 that has been thinned by the grooves 23, and therefore, even if the grooves 23 are formed, a decrease in the strength and aesthetics of the automotive display panel 20 made of the transparent resin molded body 21 is prevented. The display areas AR11, AR12, and AR13 of the transparent resin molded body 21 are areas where display is performed using light that transmits from the back surface BS to the front surface FS. The grooves 23 are located between the display areas AR11, AR12, and AR13 and the end portion 21E.

[0018] The thickness TH1 of the transparent resin molding 21 at the groove 23 is 0.5 mm or more and 2 mm or less, and is set to half or less of the thickness TH2 of the transparent resin molding 21 on both sides of the groove 23. The width of the groove 23 is, for example, 1 mm or more and 5 mm or less. The automotive display panel 20 shown in Figures 2 to 4 includes a partial light-shielding film 26. The partial light-shielding film 26 is transparent in the portions corresponding to the display areas AR11, AR12, and AR13, and is colored, for example, black in the portion corresponding to the light-shielding area AR1. The light-shielding area AR1 may be colored a color other than black as long as it can block light traveling from the back surface BS to the front surface FS of the transparent resin molding 21 so as not to be emitted from the automotive display panel 20. The light-shielding area AR1 is formed, for example, by printing ink over the entire surface of the light-shielding area AR1. The partial light-shielding film 26 is, for example, a decorative film. The partial light-shielding film 26 is provided on the surface FS of the transparent resin molded body 21 by, for example, insert molding when the transparent resin molded body 21 is injection molded.

[0019] (1-2) Automotive Display Device The automotive display device 1 includes an automotive display panel 20, a liquid crystal display 2, and a light source 3. The liquid crystal display 2 and light source 3 are disposed on the side of the back surface BS of the transparent resin molding 21. The light source 3 serves as a backlight for the liquid crystal display 2. Disposed on the side of the back surface BS means that they do not have to be in direct contact with the back surface BS of the transparent resin molding 21. Of course, they may be disposed so as to be in direct contact with the back surface BS of the transparent resin molding 21. Light emitted from the light source 3 passes through the liquid crystal display 2 and the transparent resin molding 21, and is emitted from the display areas AR11, AR12, and AR13 to the outside of the automotive display device 1. However, the light emitted from the light source 3 that passes through the transparent resin molding 21 toward the end 21E of the transparent resin molding 21 is blocked by the colored resin filler 22, and therefore is reduced compared to when the colored resin filler 22 is not present. Instead of the liquid crystal display 2 and the light source 3, a self-luminous display such as an organic light-emitting diode (OLED) display or a plasma display may be used. When an organic EL display or a plasma display is used, since it is a self-luminous type, it serves as a light source itself, and therefore there is no need to provide a separate light source.

[0020] (2) Manufacturing Method of Automotive Display Device The manufacturing method of the above-described automotive display device 1 will be described with reference to the flowchart of FIG. 5 . In the injection molding process (step S1), a transparent resin molded body 21 is injection molded. The transparent resin molded body 21 molded in the injection molding process does not yet have the grooves 23 formed therein. In other words, the predetermined shape of the transparent resin molded body 21 is the shape shown in FIGS. 2 to 4 excluding the grooves 23. The transparent resin molded body 21 is molded from a transparent resin and transmits light. Examples of transparent resins include polycarbonate resin (PC) and polymethyl methacrylate resin (PMMA). In the injection molding process, a partial light-shielding film 26 may be placed in a mold, and the partial light-shielding film 26 may be provided on the surface FS of the transparent resin molded body 21 by insert molding simultaneously with the injection molding. Alternatively, the partial light-shielding film 26 may be bonded to the surface FS of the transparent resin molded body 21 after injection molding. In the groove forming process (step S2), the groove 23 is formed by cutting using computerized numerical control (CNC) along a predetermined shape of the transparent resin molded body 21 so as to leave a predetermined thickness TH1. Using CNC makes it possible to form the groove 23 along the three-dimensional shape of the transparent resin molded body 21. In the transparent resin molded body 21 shown in FIGS. 3 and 4 , the groove 23 is formed along an arched curved shape. For example, the thickness TH1 of the transparent resin molded body 21 in the portion where the groove 23 is formed is a constant thickness, e.g., 0.5 mm. Alternatively, the thickness TH1 of the transparent resin molded body 21 in the portion where the groove 23 is formed may be formed so that it varies in the range of 0.5 mm to 1 mm, assuming that the thickness TH2 of the transparent resin molded body 21 around the groove 23 is 3 mm. When the transparent resin molded body 21 is used in an automotive display device 1, the thickness TH2 of the transparent resin molded body 21 is, for example, 2 mm to 4 mm.

[0021] The thickness TH1 of the transparent resin molded body 21 where the groove 23 is formed is preferably 0.5 mm or more and 2 mm or less, and is preferably half or less than the thickness TH2 of the transparent resin molded body on both sides of the groove 23. If the thickness TH1 of the transparent resin molded body 21 where the groove 23 is formed is too thick, more light will leak from the end 21E, etc. If the thickness TH1 of the transparent resin molded body 21 where the groove 23 is formed is too thin, the rigidity of the automotive display panel 20 will be reduced. The preferred range of the thickness TH1 described above is set by taking into account the balance between these two factors. Forming the groove 23 by injection molding may cause sink marks and warping in the transparent resin molded body 21, but forming the groove 23 by computer numerical control cutting can prevent sink marks and warping. The groove 23 is formed at least between the display areas AR11, AR12, and AR13 and the end 21E of the transparent resin molded body 21, and between adjacent display areas AR11, AR12, and AR13. In this first embodiment, for example, grooves 23 are formed around the entire periphery of the display region AR11. However, for example, if measures are taken to prevent light leaking from the top of the automotive display panel 20 from being radiated into the vehicle interior using other sealing materials, the formation of grooves above the display region AR11 may be omitted. In the filler formation step (step S3), a colored resin is filled into the grooves 23 to form colored resin fillers 22. The colored resin has the function of blocking light traveling through the transparent resin molded body 21 from the display regions AR11, AR12, and AR13 toward the end 21E and / or the adjacent display regions AR11, AR12, and AR13. Light traveling toward the adjacent display regions refers to light traveling from the display region AR11 toward the display regions AR12 and AR13, light from the display region AR12 toward the display regions AR11 and AR13, and light from the display region AR13 toward the display regions AR11 and AR12.

[0022] Colored resins are resins that are colored by mixing colorants into them. Examples of colorants include pigments and dyes. Resins that make up colored resins include thermoplastic resins, thermosetting resins, and UV-curable resins. Examples of thermoplastic resins include polypropylene resin. Examples of thermosetting resins include urethane resin. Examples of UV-curable resins include acrylic resin. Thermoplastic resins, as materials for colored resins, are excellent in processability because they soften with heat, and are easy to uniformly mix with pigments, making it easy to achieve a uniform color distribution. They are also suitable for recycling because they can be softened and remolded by heat. In the assembly process (step S4), the automotive display device 1 is assembled. In this assembly process, the automotive display panel 20 is combined with the liquid crystal display 2 and light source 3. Alternatively, other displays and light sources, such as an organic electroluminescence (EL) display or a plasma display, can be used instead of the liquid crystal display 2 and light source 3.

[0023] Second Embodiment (3) Configuration and Manufacture of Automotive Display Device In the first embodiment, various information and images are displayed using a liquid crystal display 2, an organic EL display, or a plasma display. However, some automotive display devices 1 display information by switching between on and off, such as the icons on the heater control panel 30. In FIG. 6 , the partial light-shielding film 26 in the display areas AR14, AR15, AR16, and AR17 of the automotive display device 1 according to the second embodiment is printed with a light-transmitting icon pattern that allows only light to pass through. Four LEDs 3L corresponding to the display areas AR14, AR15, AR16, and AR17 are arranged on the back surface BS as light sources 3. A power icon is arranged in the display area AR14, and when the LED 3L corresponding to the display area AR14 is lit, the power icon lights up. The light of the power icon informs the driver that the heater is on. In the automotive display panel 20 of the automotive display device 1 of the second embodiment, similar to the first embodiment, colored resin fillers 22 (grooves 23) are disposed between adjacent display areas AR14, AR15, AR16, and AR17. Furthermore, colored resin fillers 22 (grooves 23) are disposed between the display areas AR14 and AR17 and the end 21E of the transparent resin molded body 21. For example, even if the power icon is illuminated, the colored resin fillers 22 are disposed between the display area AR14 of the power icon and the adjacent display area AR15, thereby preventing leakage of light for illuminating the power icon into the display area AR15. The automotive display device 1 of the second embodiment can be manufactured using the same manufacturing flow as the automotive display device 1 of the first embodiment, and therefore, a description of the manufacturing method for the automotive display device 1 of the second embodiment will be omitted here.

[0024] Third Embodiment (4) Configuration and Manufacturing of Automotive Display Device In the automotive display device 1 of the first embodiment, the shape of the transparent resin molded body 21 in the area where the liquid crystal display 2 and light source 3 are located remains the same as the shape formed by injection molding. An example of the configuration of the automotive display device 1 according to the third embodiment is shown in FIG. 7 . As shown in FIG. 7 , in the automotive display device 1 according to the third embodiment, the transparent resin molded body 21 in the display area AR11 corresponding to the area where the liquid crystal display 2 and light source 3 are located is made thinner than the periphery RN1 of the display area AR11 by machining using computer numerical control. In other words, the following equation holds: (thickness TH3 of the transparent resin molded body 21 in the thinned portion P1 corresponding to the display area AR11) < (thickness TH4 of the periphery RN1 of the display area AR11). When the transparent resin molded body 21 is used in the automotive display device 1, the thickness TH4 of the periphery RN1 of the display area AR11 is, for example, 2 mm to 4 mm. Furthermore, the difference (TH4-TH3) between the thickness TH3 of the transparent resin molding 21 at the thinned portion P1 and the thickness TH4 of the periphery RN1 of the display region AR11 is, for example, 0.5 mm to 2 mm. While FIG. 7 depicts the wall between the periphery RN1 of the display region AR11 and the thinned portion P1 as inclined, this wall may be formed perpendicular to the surface of the thinned portion P1 or the surface of the periphery RN1. A vertical wall is convenient for storing the OCR fluid, making it easier to bond, for example, the liquid crystal display 2. A manufacturing flow for the automotive display device 1 according to the third embodiment is shown in FIG. 8. The manufacturing flow for the automotive display device 1 according to the third embodiment differs from the manufacturing flow for the first embodiment shown in FIG. 5 in that it includes a thinning process (step S2'). In the thinning step, similarly to the groove forming step (step S2), cutting using computer numerical control (CNC) is performed to thin the display area AR11 of the transparent resin molding 21 along a predetermined shape of the transparent resin molding 21. Here, the case where the thinning step (step S2') is performed after the groove forming step (step S2) has been described, but the order of performing these steps may be reversed.Thinning a wide area such as the display area AR11 is difficult due to the fluidity of the resin, since the transparent resin molded body 21 is originally thin, for example, at 3 mm. Thinning the display area AR11 by injection molding may cause sink marks and warping in the transparent resin molded body 21. In contrast, thinning the display area AR11 by cutting using computer numerical control eliminates the molding difficulties caused by the fluidity of the resin, and makes it possible to prevent sink marks and warping.

[0025] Fourth Embodiment (5) Configuration and Manufacture of Automotive Display Device In the automotive display device 1 of the third embodiment, the liquid crystal display 2 and light source 3 are disposed on the back surface BS of the thinned transparent resin molded body 21. In the third embodiment, cutting marks remain on the back surface BS of the thinned transparent resin molded body 21. In the automotive display device 1 of the third embodiment, the cut portion is polished to remove the cutting marks. Alternatively, in the automotive display device 1 of the third embodiment, a coating agent is applied to the cut portion to remove the cutting marks. However, in the automotive display device 1 of the third embodiment, an air layer is interposed between the liquid crystal display 2 and light source 3 and the back surface BS of the transparent resin molded body 21. In the automotive display device 1 of the fourth embodiment, an optical clear resin 41 or an optical clear adhesive 42 is disposed between the liquid crystal display 2 and the portion P1 of the display area AR11 that is thinner than the surrounding area due to cutting (see FIG. 9 ). The optically transparent resin 41 or optically transparent adhesive 42 placed in the cutting traces penetrates into the unevenness of the cutting traces, preventing diffused reflections that occur in the cutting traces. Comparing the optically transparent resin 41 and the optically transparent adhesive 42, the optically transparent resin 41 has higher fluidity and is more effective at filling cutting traces, making it preferable for use in the cut portions of the transparent resin molded body 21. However, the optically transparent adhesive 42 is a tape-shaped adhesive, which is easier to work with. Furthermore, because the liquid crystal display 2 and the optically transparent resin 41 or the optically transparent adhesive 42 are in close contact with each other, reflections at the interface between the air and the resin are prevented, suppressing a decrease in the amount of light traveling from the liquid crystal display 2 toward the surface FS of the automotive display panel 20. As a result, reduced visibility due to cutting traces can be prevented.

[0026] To prevent a decrease in visibility, it is preferable that the refractive index of the optical transparent resin 41 or the optical transparent adhesive 42 be within plus or minus 0.1 of the refractive index of the transparent resin molded body 21 (refractive index of the transparent resin molded body 21 - 0.1 ≦ refractive index of the optical transparent resin 41 or the optical transparent adhesive 42 ≦ refractive index of the transparent resin molded body 21 + 0.1). For example, if the transparent resin molded body 21 is a polycarbonate resin (refractive index 1.58), it is preferable to use an optical transparent resin 41 or an optical transparent adhesive 42 having a refractive index of 1.48 to 1.68 for bonding the transparent resin molded body 21 to the liquid crystal display 2. For example, if the transparent resin molded body 21 is a polymethyl methacrylate resin (refractive index 1.49), it is preferable to use an optical transparent resin 41 or an optical transparent adhesive 42 having a refractive index of 1.39 to 1.59 for bonding the transparent resin molded body 21 to the liquid crystal display 2. The optically transparent resin 41 or the optically transparent adhesive 42 is used in the assembly process (step S4) of Figure 8 to bond the liquid crystal display 2 to the thinned portion P1 of the optically transparent resin 41. The bonding process is a process of bonding the liquid crystal display 2 to the portion P1 that has been thinned by cutting in the thinning process using the optically transparent resin 41 or the optically transparent adhesive 42. After assembly, the optically transparent resin 41 or the optically transparent adhesive 42 is in close contact with the liquid crystal display 2 and the optically transparent resin 41. Note that even when an organic EL display or a plasma display is used instead of the liquid crystal display 2, the organic EL display or the plasma display can be bonded to the transparent resin molded body 21 using the optically transparent resin 41 or the optically transparent adhesive 42.

[0027] Fifth Embodiment (6) Configuration and Manufacture of Automotive Display Device FIG. 10 shows an example of the configuration of an automotive display device according to the fifth embodiment. The automotive display device 1 shown in FIG. 10 differs from the automotive display device 1 of the fourth embodiment shown in FIG. 9 in that a boss 50 is provided on the rear surface BS of the transparent resin molded body 21, and the transmittance of the boss 50 is adjusted to make it difficult to see from outside the automotive display panel 20. The structure provided on the rear surface BS of the transparent resin molded body 21 may be something other than the boss 50, such as a rib or a clip seat. To make the structure provided on the rear surface BS of the transparent resin molded body 21 difficult to see, at least one of a pigment and a colorant is added to the transparent resin molded body 21. The preferred range of total light transmittance to make the structure provided on the rear surface BS of the transparent resin molded body 21 difficult to see is 20% or more and 70% or less. The total light transmittance is measured in accordance with JIS K7375. The fifth embodiment of the automotive display device 1 can be manufactured using the same manufacturing flow as the fourth embodiment of the automotive display device 1, except that the resin and mold used for the transparent resin molding 21 are different, so here we will omit the explanation of the manufacturing method for the fifth embodiment of the automotive display device 1.

[0028] (7) Modifications In the above embodiments, the automotive display device 1 has been described with a focus on cases where it has a function solely for display. However, the automotive display device 1 may also be provided with a touch sensor and function as both a display device and an input device. The touch sensor is disposed in a position where input can be performed by touching the automotive display panel 20. The touch sensor is disposed, for example, on the front surface FS or back surface BS of the transparent resin molding 21. When the touch sensor is disposed on the front surface FS of the transparent resin molding 21, for example, the touch sensor is disposed between the transparent resin molding 21 and the partial light-shielding film 26. When the touch sensor is disposed on the back surface BS of the transparent resin molding 21, for example, the touch sensor is disposed between the transparent resin molding 21 and the liquid crystal display 2.

[0029] (8) Features (8-1) The manufacturing method of the automotive display device 1 according to the first to fifth embodiments described above includes a groove forming step of forming grooves 23 by cutting using computer numerical control along a predetermined shape so as to leave a predetermined thickness between the display regions AR11 to AR17 and the end 21E of the transparent resin molded body 21, and / or between adjacent display regions AR11 to AR17, and a filler forming step of filling the grooves 23 with a colored resin to form a colored resin filler 22 in the grooves 23. As a result, since the grooves 23 are not formed by injection molding, sink marks and warping can be prevented when forming the grooves 23. Furthermore, since the colored resin is filled into the grooves 23 to form the colored resin filler 22 in the grooves 23, the transparent resin molded body 21 around the grooves 23 is integrated with the colored resin filler 22, and the transparent resin molded body 21 is reinforced by the colored resin filler 22. As a result, it is possible to suppress deterioration in the strength and appearance of the automotive display panel 20 due to the formation of the grooves 23, and to prevent abnormal noise caused by vehicle vibrations. Furthermore, the colored resin filler 22 in the grooves 23 can reduce light leaking into the end 21E of the transparent resin molded body 21 and / or the adjacent display areas AR11 to AR17.

[0030] (8-2) By setting the thickness TH1 (see FIG. 4) of the transparent resin molded body 21 remaining when forming the groove 23 to 0.5 mm or more and 2 mm or less, and half or less of the thickness TH2 (see FIG. 4) of the transparent resin molded body 21 on both sides of the groove 23, it is possible to appropriately adjust the reduction in light leakage and the suppression of a decrease in the strength of the automotive display panel 20. (8-3) As described in the third and fourth embodiments, when the display region AR11 of the transparent resin molded body 21 is thinned to a predetermined shape by cutting using computer numerical control, molding difficulties due to the fluidity of the resin, such as injection molding, are eliminated, making molding easier. Furthermore, thinning the display region AR11 by cutting using computer numerical control eliminates molding difficulties due to the fluidity of the resin, and it is possible to prevent sink marks and warpage from occurring in the display region AR11.

[0031] (8-4) As described in the fourth embodiment, by bonding, for example, a liquid crystal display 2, an organic EL display, or a plasma display to the portion P1 of the transparent resin molded body 21 that has been thinned by cutting, using the optical transparent resin 41 or the optical transparent adhesive 42, the visibility of the display can be improved. (8-5) The refractive index of the optical transparent resin 41 or the optical transparent adhesive 42 is preferably set to a value equal to or greater than the refractive index of the transparent resin molded body 21 minus 0.1 and equal to or less than the refractive index of the transparent resin molded body 21 plus 0.1. Setting the refractive index of the optical transparent resin 41 or the optical transparent adhesive 42 within this range can improve the visibility of the display. While the first to fifth embodiments of the present invention have been described above, the present invention is not limited to these embodiments and various modifications are possible without departing from the spirit and scope of the invention. In particular, the multiple embodiments and modifications described herein can be arbitrarily combined as needed.

[0032] REFERENCE SIGNS LIST 1 Automotive display device 2 Liquid crystal display 3 Light source 3L LED 20 Automotive display panel 21 Transparent resin molded body 21E End 22 Colored resin filler 23 Groove 41 Optical transparent resin 42 Optical transparent adhesive AR11 to AR17 Display area

Claims

1. A method for manufacturing a display device for an automobile, comprising: an injection molding process for injection molding a transparent resin molded body having a predetermined shape and transmitting light; a groove forming process for forming a groove by cutting using computer numerical control along the predetermined shape so as to leave a predetermined thickness between a display area which displays using light transmitted from the back surface of the transparent resin molded body to the front surface and the edge of the transparent resin molded body, and / or between adjacent display areas; and a filler forming process for filling the groove with a colored resin which blocks light traveling through the transparent resin molded body, to form a colored resin filler in the groove.

2. The method for manufacturing an automobile display device according to claim 1, wherein the specified range is between 0.5 mm and 2 mm, and is equal to or less than half the thickness of the transparent resin molding on both sides of the groove.

3. A method for manufacturing an automotive display device as described in claim 1 or 2, further comprising a thinning process for thinning the display area of ​​the transparent resin molding to conform to the specified shape by cutting using computer numerical control.

4. A method for manufacturing an automotive display device as described in claim 3, further comprising a bonding process of bonding a display to the portion that has been thinned by cutting in the thinning process using an optical clear resin or an optical clear adhesive.

5. A method for manufacturing an automotive display device as described in claim 4, wherein the refractive index of the optically transparent resin or the optically transparent adhesive is equal to or greater than the refractive index of the transparent resin molding minus 0.1 and equal to or less than the refractive index of the transparent resin molding plus 0.

1.

6. A display panel for an automobile comprising: a light-transmitting transparent resin molding having a predetermined shape and a groove formed by cutting along the predetermined shape; and a colored resin filler made of a colored resin that fills the groove and blocks light traveling through the transparent resin molding, wherein the transparent resin molding has a display area that displays with light that transmits from the back surface to the front surface, the groove being disposed between the display area and an end of the transparent resin molding and / or between adjacent display areas, and the thickness of the groove portion of the transparent resin molding is 0.5 mm or more and 2 mm or less, and is half or less the thickness of the transparent resin molding on both sides of the groove.

7. The automotive display panel according to claim 6, wherein the display area of ​​the transparent resin molding is made thinner than the surrounding area of ​​the display area by cutting.

8. A display device for an automobile comprising: a light-transmitting transparent resin molded body having a predetermined shape and a groove formed by cutting along the predetermined shape; a colored resin filler made of a colored resin that fills the groove and blocks light traveling through the transparent resin molded body; and a light source that is arranged on the back surface side of the transparent resin molded body and emits light that transmits through the transparent resin molded body, wherein the transparent resin molded body has a display area that displays using light that transmits from the back surface to the front surface, the groove is arranged between the display area and an end of the transparent resin molded body and / or between adjacent display areas, and the thickness of the groove portion of the transparent resin molded body is 0.5 mm or more and 2 mm or less, and is half or less the thickness of the transparent resin molded body on both sides of the groove.

9. The automotive display device described in claim 8, wherein the transparent resin molding has a display area that is made thinner than the surrounding area by cutting, and the transparent resin molding is provided with an optical clear resin or an optical clear adhesive that bonds a display that displays using the light source to the thin portion of the display area.

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