JP2009265287A - Reflecting mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflecting mirror used for a display device such as a head-up display, distortion generated on the front of a substrate constituting a reflecting surface being reducible. <P>SOLUTION: The reflecting mirror 41 has a reflecting film 45 formed on the front surface (first concave surface) 44 of a substrate 43 made of resin, and a side surface portion 43b of the substrate 43 has a gate portion 43c, formed of a gate trace formed during injection molding of the substrate, at a position apart from the front surface 44 (reflecting film 45). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reflection mirror used in a display device such as a head-up display.

  Conventionally, as a display device using a reflection mirror that reflects display light, there is a head-up display, which is disclosed in Patent Document 1, for example. Such a head-up display described in Patent Document 1 is attached to the inside of an instrument panel (hereinafter referred to as an instrument panel) of a vehicle, and projects display light emitted from a display device onto a windshield (projection member) of the vehicle. A virtual image is displayed to a vehicle user (driver).

  The display device includes a light source, a display that emits display light in accordance with light emission of the light source, a concave mirror (reflection mirror) for reflecting the display light emitted from the display to the windshield, a display and a concave mirror, And a housing having a translucent part that transmits display light reflected by the concave mirror, and projecting the display light reflected by the concave mirror onto the windshield through the translucent part to display a virtual image To do.

  In this case, the concave mirror that is a reflection mirror includes a substrate and a reflection film formed on the front surface of the substrate (a surface facing the display). The substrate is made of resin such as polycarbonate having a predetermined plate thickness, and is molded by injection molding so that the front surface and the back surface facing the front surface form a concave curved surface having a predetermined curvature.

The reflective film is made of a metal such as aluminum and is formed on the front surface of the substrate by means such as vapor deposition. Therefore, the front surface of the concave mirror after the formation of the reflective film is a reflective surface composed of a concave curved surface (that is, a concave surface). The concave mirror configured in this manner has a function of expanding the display light emitted from the display and projecting the expanded display light onto the windshield through the light transmitting portion.
JP 2005-338680 A

  FIG. 6 shows a mold 100 for forming a concave mirror substrate in the prior art. The mold 100 includes an upper mold (movable mold) 101 and a lower mold (fixed mold) 102.

  The upper mold 101 has a first curved surface portion 101a for forming a concave curved surface (concave surface) corresponding to the front surface of the substrate to be a molded product. Further, the lower mold 102 has a second curved surface portion 102a for forming a concave curved surface corresponding to the back surface of the substrate to be a molded product. In this case, the curvature of the second curved surface portion 102a is the first curved surface portion 102a. This is substantially the same as the curvature of the first curved surface portion 101a.

  A molding space 103 corresponding to the shape of the substrate is formed between the upper mold 101 and the lower mold 102, and a gate port 104 communicating with the molding space 103 is provided in the lower mold 102. It becomes. Reference numeral 104 a denotes a resin inflow passage which is located on the right side of the gate port 104 in FIG. 6 so as to communicate with the gate port 104 and flows the molten resin 105 made of polycarbonate resin into the gate port 104.

  The opening width W1 of the molding space 103 on the gate opening 104 side and the opening width W2 of the gate opening 104 communicating with the opening width W1 are substantially the same opening width. Reference numeral 106 denotes a mating surface (so-called parting line) between the upper mold 101 and the lower mold 102, and the mating surface 106 is a horizontal plane continuous to both ends of the first curved surface portion 101 a of the upper mold 101. The region extending from the mating surface 106 to the outer edge of the second curved surface portion 102a in the lower mold 102 is the opening width W2 of the gate port 104.

  In forming a concave mirror substrate using the mold 100, first, the upper mold 101 is pressed against the lower mold 102 to seal the molding space 103, and the molding space is formed through the resin inflow path 104 a and the gate port 104. After injecting molten resin 105 into 103, this molten resin 105 is solidified. Next, the upper mold 101 is removed and moved in a predetermined direction, so that the molten resin 105 solidified in the lower mold 102 remains. Finally, the solidified molten resin 105 is released from the lower mold 102 by an ejector pin (not shown) provided in the lower mold 102, and an unnecessary part (runner part) is cut to form a molded product. The substrate will be completed.

  Here, the unnecessary portion means a solidified molten resin 105 portion remaining in the resin inflow path 104a and the gate port 104 when the upper mold 101 is pulled and moved in a predetermined direction after the molten resin 105 is solidified. Do it. As shown in FIG. 7 which is a front view when the substrate 110 is viewed from the front, the substrate 110 which is a molded product obtained by cutting such unnecessary portions is positioned on the right side in FIG. In the substantially central portion of the side surface portion 112, a gate portion 113 made of a gate mark resulting from the cutting of the unnecessary portion is generated.

  Further, as shown in FIG. 8 which is an XX cross-sectional view of FIG. 7, the substrate 110 has a first curved surface 114 having a concave curved surface corresponding to the shape of the first curved surface portion 101 a of the upper mold 101. In addition to being formed as a concave surface, the back surface 115 is formed as a second concave surface having a concave curved surface corresponding to the shape of the second curved surface portion 102 a of the lower mold 102. The curvature of the front surface (first concave surface) 114 is substantially the same as the curvature of the back surface (second concave surface) 115.

  Here, when the molten resin 105 is injected into the molding space 103 through the gate port 104 and solidified, and further, the runner portion is cut to obtain a substrate 110 as a finished product, as described above, the opening of the molding space 103 is opened. Since the width W1 and the opening width W2 of the gate port 104 are substantially the same opening width, a substantially central portion of the side surface portion 112 corresponding to the gate port 104 is provided from the front surface (first concave surface) 114 to the back surface. A gate mark (gate portion) 113 is formed over substantially the entire region reaching the (second concave surface) 115. Then, a reflective film 116 is deposited on the entire first concave surface 114 after the gate portion 113 is formed so as to be adjacent to the gate portion 113, thereby forming a concave mirror (reflective surface) having the first concave surface 114 of the substrate 110 as a reflective surface. Mirror) 120 is obtained.

  However, the gate mark (gate portion) 113 of the substrate 110 generated by cutting the unnecessary portion is changed from the front surface (first concave surface) 114 to the back surface (second concave surface) 115 before the reflective film 116 is formed. When the first concave surface 114 is located near the gate portion 113, the stress due to the cutting of the unnecessary portion acts on the first concave surface 114, particularly in the vicinity of the gate portion 113. The first concave surface 114 is distorted.

If the reflective film 116 is formed on the entire first concave surface 114 including the first concave surface 114 near the gate portion 113, the reflective film 116 near the gate portion 113 is also distorted. become. That is, with the formation of the reflective film 116, the concave mirror 120 on which the reflective surface is formed is in a state in which a part of the reflective surface is distorted, and the concave mirror 120 in which a part of the reflective surface is distorted is used. When the display device is assembled, there is a problem that the virtual image of the head-up display is distorted.
SUMMARY OF THE INVENTION In order to address the above-described problems, an object of the present invention is to provide a reflection mirror that can reduce distortion generated on the front surface of a substrate constituting a reflection surface.

  The present invention is a reflecting mirror in which a reflecting film is formed on the front surface of a resin substrate, and the side surface of the substrate is formed at a position away from the reflecting film by injection molding. The gate portion is formed.

  According to the present invention, it is possible to provide a reflection mirror that can achieve the initial object and can reduce distortion generated on the front surface of the substrate constituting the reflection surface.

  Hereinafter, an embodiment in which a reflection mirror of the present invention is applied to a head-up display for a vehicle will be described with reference to the accompanying drawings. 1 to 5 show an embodiment of the present invention, FIG. 1 is a schematic view of a head-up display according to the embodiment of the present invention, FIG. 2 is a cross-sectional view of the head-up display according to the embodiment, 3 is a view showing a mold for forming a substrate of the reflecting mirror according to the embodiment, FIG. 4 is a front view of the substrate after forming according to the embodiment, and FIG. 5 is a cross-sectional view taken along line AA of FIG.

  As shown in FIG. 1, the head-up display is configured such that the display light L projected by the display device 12 that is a display unit disposed inside the instrument panel 11 of the vehicle 10 is the windshield 13 of the vehicle 10 that is a projection member. The virtual image V is displayed by reflecting in the direction of the driver (user) 14. In other words, the head-up display emits (projects) display light L emitted from a liquid crystal display (described later) of the display device 12 onto the windshield 13 (the projection member), and a display image (virtual image) obtained by the emission. ) V is made visible to the driver 14. Thus, the driver 14 can observe the virtual image V superimposed on the landscape.

  As shown in FIG. 2, the display device 12 mainly includes a liquid crystal display 20, a first reflector 30, a second reflector 40, and a housing 50.

  The liquid crystal display 20 has a light source 21 formed of a light emitting diode mounted on the wiring board R and a front side (directly above) the light source 21 so as to transmit the illumination light from the light source 21 and form the display light L. It is mainly comprised from the TFT type liquid crystal display element 22 located. This means that the light source 21 is disposed behind (directly below) the liquid crystal display element 22, and the liquid crystal display element 22 displays predetermined information (information to be described later) by the light emitted from the light source 21. I mean. The liquid crystal display 20 is provided in the housing 50 such that the surface on the emission side of the display light L faces a cold mirror (to be described later) of the first reflector 30, and the optical axis of the display light L is on the cold mirror. Fixed and held at a crossing position and orientation.

  Further, the liquid crystal display element 22 emits and displays information (for example, the speed of the vehicle and the engine speed) to be displayed by an element driving circuit (not shown) by numerical values. The liquid crystal display 20 outputs display light L composed of light in the visible wavelength range. For example, a light source 21 that emits red light (mainly emission wavelength range of 610 to 640 nm) can be applied. Needless to say, the information to be displayed is not limited to the speed of the vehicle and the engine speed, and any display form can be adopted.

  The first reflector 30 includes a cold mirror 31 and an attachment member 32 for attaching and fixing the cold mirror 31 using predetermined attachment means. The cold mirror 31 includes a substantially rectangular glass substrate 31a and a reflective layer 31b formed on one surface of the glass substrate 31a (a surface facing a concave mirror described later of the second reflector 40). The reflective layer 31b is made of multilayer interference films having different film thicknesses, and is formed by a method such as vapor deposition. Further, the cold mirror 31 is disposed in an inclined state at a position where the display light L emitted from the liquid crystal display 20 (liquid crystal display element 22) is reflected toward the second reflector 40 (the concave mirror). .

  The cold mirror 31 reflects light in the visible wavelength range (450 to 750 nm) including the emission wavelength range of the liquid crystal display 20 with a high reflectance (for example, 80% or more), and lowers light outside the visible wavelength range. It reflects with reflectivity. In this case, a cold mirror 31 that reflects light in the infrared wavelength region other than the visible wavelength region (infrared rays or heat rays of sunlight) with a low reflectance (for example, 15% or less) is applied. The light that is not reflected by the reflective layer 31 b is configured to pass through the cold mirror 31. The attachment member 32 is made of, for example, a black synthetic resin material and is fixed to the housing 50.

  The second reflector 40 includes a concave mirror 41 that is a reflection mirror that reflects the display light L from the cold mirror 31 and a mirror holder 42 that holds the concave mirror 41.

  The concave mirror 41 includes a substrate 43 made of resin (for example, polycarbonate) and a reflective film 45 made of a metal such as aluminum deposited on the front surface 44 of the substrate 43 (that is, the surface facing the reflective layer 31b of the cold mirror 31). In this case, the front surface 44 is a concave curved surface (concave surface) having a predetermined curvature. Therefore, when the reflection film 45 is formed on the concave front surface 44, the front surface 44 becomes a reflection surface for reflecting the display light L from the cold mirror 31 to the light-transmitting cover side described later of the housing 50. . The concave mirror 41 is disposed in an inclined state at a position where the reflective film 45 (the reflective surface) faces the cold mirror 31 and the translucent cover and faces the translucent cover.

  The concave mirror 41 is for reflecting (projecting) the display light L from the cold mirror 31 toward the translucent cover (the windshield 13 of the vehicle 10). This means that the concave mirror 41 enlarges the display light L reflected by the cold mirror 31 and projects the enlarged display light L onto the windshield 13 through the translucent cover. The concave mirror 41 is bonded to the mirror holder 42 with a double-sided adhesive tape. The mirror holder 42 is made of synthetic resin (for example, ABS resin) and is fixed to the housing 50.

  The housing 50 is made of, for example, a black light-shielding synthetic resin material, and is formed in a substantially box shape. The housing 50 holds the liquid crystal display 20 and the first and second reflectors 30 and 40 in the space 51 that is the internal space. And includes an opening window 52 in which an upper portion (on the side of the windshield 13) of the concave mirror 41 in the second reflector 40 is opened.

  The housing 50 is provided with a translucent cover 53 which is a translucent part so as to close the opening window part 52. The translucent cover 53 is made of a translucent synthetic resin material (for example, acrylic resin), is formed in a curved shape (curved surface shape), and transmits light that allows the display light L reflected by the concave mirror 41 to pass (pass). It has a function as a sex member. In other words, the display light L reflected by the concave mirror 41 is projected onto the windshield 13 through the translucent cover 53 formed in the housing 50, whereby the virtual image V is displayed to the driver 14.

  The display device 12 is configured by the above-described units. FIG. 3 shows a mold 60 for molding (injection molding) the substrate 43 of the concave mirror 41 which is one component of the display device 12. The mold 60 includes an upper mold (movable mold) 61 and a lower mold (fixed mold) 62.

  The upper mold 61 has a first curved surface portion 61a corresponding to the shape of the front surface 44 of the substrate 43 that is a molded product. The lower mold 62 has a second curved surface portion 62a corresponding to the shape of the back surface (described later) of the substrate 43 located on the side opposite to the front surface 44. In this case, the second curved surface portion 62a has a second curved surface portion 62a. The curvature is substantially the same as the curvature of the first curved surface portion 61a.

  A molding space 63 corresponding to the shape of the substrate 43 is formed between the upper mold 61 and the lower mold 62, and a gate port 64 communicating with the molding space 63 is provided in the lower mold 62. It will be. In addition, 64a is a resin inflow path for pouring molten resin, which will be described later, into the gate port 64, which is located to the right of the gate port 64 in FIG. 3 so as to communicate with the gate port 64.

  In the case of the present embodiment, the first opening width T1 of the molding space 63 on the gate opening 64 side and the second opening width T2 of the gate opening 64 communicating with the first opening width T1 are the same opening width. The second opening width T2 is communicated with the first opening width T1 so that the second opening width T2 is slightly narrower than the first opening width T1. Specifically, in FIG. 3, the second opening width T2 on the gate port 64 side is set slightly smaller than the first opening width T1 on the molding space 63 side, and the second opening width T2 is set to the first opening width T1. Is configured to communicate with the lower side of the first opening width T1.

  Note that PL is a mating surface (so-called parting line) between the upper mold 61 and the lower mold 62. The mating surface PL is composed of a first mating surface PL1 and a second mating surface PL2.

  Although the detailed illustration is omitted, the first mating surface PL1 is a mating surface of the molds 61 and 62 in a place excluding the boundary region between the molding space 63 and the gate port 64 and the region in the vicinity thereof. Suppose that it is comprised so that it may continue in an end part of the 1st curved surface part 61a. On the other hand, the second mating surface PL2 is a mating surface of the molds 61 and 62 in the boundary region between the molding space 63 and the gate port 64 and the region in the vicinity thereof, and is one step higher than the first mating surface PL1. It is assumed that it is formed at a low position. A region extending from the second mating surface PL2 to the outer edge of the second curved surface portion 62a in the lower mold 62 is the second opening width T2 of the gate port 64.

  In forming the substrate 43 using the mold 60, first, the upper mold 61 is pressed against the lower mold 62 to seal the molding space 63, and the molding space 63 is formed through the resin inflow path 64 a and the gate port 64. After injecting a molten resin 65 made of polycarbonate resin or the like, the molten resin 65 is solidified. Next, the upper mold 61 is removed and moved in a predetermined direction, whereby the molten resin 65 solidified in the lower mold 62 remains. Finally, the solidified molten resin 65 is released from the lower mold 62 by an ejector pin (not shown) provided in the lower mold 62, and an unnecessary part (runner part) is cut to form a molded product. A substrate 43 is completed.

  The unnecessary portion mentioned here means the solidified molten resin 65 portion remaining in the gate port 64 and the resin inflow passage 64a when the upper mold 61 is pulled and moved in a predetermined direction after the molten resin 65 is solidified. Do it. As shown in FIG. 4 which is a diagram when the substrate 43 is viewed from the front, the substrate 43 which is a molded product obtained by cutting such unnecessary portions has a side surface located on the right side in FIG. 4 among the four side surfaces 43a. In a substantially central portion of the portion 43b, a gate portion 43c is formed which is formed of a gate mark accompanying the cut of the unnecessary portion.

  In the case of the present embodiment, the outer shape of the substrate 43 is formed in a substantially rectangular shape, and the gate portion 43 c is a substantially central portion of the side surface portion 43 b formed along a direction substantially orthogonal to the longitudinal direction of the substrate 43. For example, the gate part 43c is formed along the longitudinal direction of the substrate 43, for example, the side part 43a (that is, the side part 43a located above or below the base part 43 in FIG. 4). It is good also as a structure located in the approximate center part.

  Further, as shown in FIG. 5, the front surface 44 of the substrate 43 is formed as a first concave surface having a concave curved surface corresponding to the shape of the first curved surface portion 61 a of the upper mold 61, and the rear surface 46 thereof. Is formed as a second concave surface having a concave curved surface corresponding to the shape of the second curved surface portion 62 a of the lower mold 62. The curvature of the front surface (first concave surface) 44 is substantially the same as the curvature of the back surface (second concave surface) 46.

  Here, as described above, the molten resin 65 is injected into the molding space 63 through the resin inflow path 64a and the gate port 64, solidified, and the runner portion is cut to obtain the finished substrate 43. The second opening width T2 on the gate port 64 side is set to be slightly smaller than the first opening width T1 on the molding space 63 side, and the second opening width T2 avoids the upper side of the first opening width T1, It communicates with the lower side of the opening width T1.

  Accordingly, in the substantially central portion of the side surface portion 43 b corresponding to the gate port 64, a position away from the front surface 44 rather than a substantially entire region from the front surface 44 to the back surface 46 (that is, the concave mirror 41 after the reflective film 45 is formed on the substrate 43. In this case, a gate portion (gate mark) 43c corresponding to the shape of the gate port 64 is formed at a position apart from the reflective film 45 by a predetermined distance without being adjacent to the reflective film 45 (see FIG. 5). Then, by forming a reflective film 45 on the entire front surface (first concave surface) 44 of the substrate 43 having the gate portion 43c, a concave mirror (reflective mirror) 41 having the first concave surface 44 as the reflective surface is obtained. It is done.

  At this time, since the gate portion 43c is provided at a predetermined distance from the front surface 44, stress due to the cut of the runner portion is less likely to act on the front surface 44 side. It is possible to reduce the distortion generated at the 44 positions on the front surface which is the (surrounding). Thereby, the substrate 43 in which the distortion of the front surface 44 is suppressed can be obtained. Accordingly, when the display device 12 is assembled using the concave mirror (reflection mirror) 41 after the reflection film 45 is formed on the entire front surface 44 in which distortion is suppressed in this way, the problem that the virtual image of the head-up display is distorted is It will be resolved.

  As described above, in the present embodiment, the concave mirror (reflection mirror) 41 is formed by forming the reflective film 45 on the front surface (first concave surface) 44 of the substrate 43 made of resin, The gate portion 43c formed of a gate mark when the substrate 43 is formed by injection molding is formed at a position away from the front surface 44 (that is, the reflective film 45), so that the stress due to the cut of the runner portion is reduced by the front surface. Since it becomes difficult to act on the 44 side, the distortion of the front surface 44 constituting the reflection surface can be reduced.

  In the present embodiment, an example in which the concave mirror 41 is employed as the reflection mirror has been described. However, instead of the concave mirror 41, a convex mirror or a plane mirror may be employed.

  In the present embodiment, the example in which the display light L emitted from the liquid crystal display element 22 is projected onto the windshield 13 has been described. However, for example, a combiner that reflects the display light L on the windshield 13 in the direction of the driver 14 well. A film may be provided, or the display light L may be projected onto a dedicated reflecting member different from the windshield 13.

It is the schematic of the head-up display by embodiment of this invention. It is sectional drawing of the head-up display by the embodiment. It is a figure which shows the metal mold | die which shape | molds the board | substrate of the reflective mirror by the same embodiment. It is a front view of the board | substrate after the shaping | molding by the same embodiment. It is AA sectional drawing of FIG. It is a figure which shows the metal mold | die which shape | molds the board | substrate of the reflective mirror by a prior art. It is a front view of the board | substrate after a shaping | molding by a prior art. It is XX sectional drawing of FIG.

Explanation of symbols

40 Second reflector 41 Concave mirror (reflection mirror)
43 Substrate 43b Side part 43c Gate part (gate trace)
44 Front (first concave surface)
45 Reflective film 46 Back surface (second concave surface)
60 mold 61 upper mold (movable mold)
62 Lower mold (fixed mold)
63 Molding space 64 Gate port 65 Molten resin PL Mating surface (parting line)
PL1 first mating surface PL2 second mating surface T1 first opening width T2 second opening width

Claims (1)

A reflection mirror formed by forming a reflection film on the front surface of a substrate made of resin,
A reflection mirror, wherein a gate portion for molding the substrate by injection molding is formed on a side surface portion of the substrate at a position away from the reflection film.

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