JP2008262039A - Luminous device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a luminous device which can be thinned. <P>SOLUTION: A first transmission reflection member 28 reflects a part of light emitted by a luminous element 27 and reflects the other part. A second transmission reflection member 29 reflects a part of light transmitted by the first transmission reflection member 28 and transmits the other part. A reflection member 31 reflects at least a part of light transmitted by the second transmission reflection member 29. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device having a light emitting element such as a light emitting diode and illuminating a liquid crystal display panel or the like.

Conventionally, various head-up display devices for vehicles have been proposed, and for example, disclosed in Patent Document 1. Such a head-up display device 1 for a vehicle projects a display light L on a semi-transmissive plate called a windshield 2 or a combiner of the vehicle to display a virtual image V (see FIG. 3). The vehicle head-up display device 1 includes a housing 3 in which a liquid crystal display 4 and a reflection mirror 5 are accommodated, and the display light L emitted from the liquid crystal display 4 is reflected by the reflection mirror 5 to provide a translucent cover. 6 is projected onto the windshield 2 or the semi-transmissive plate (see FIG. 4).
The liquid crystal display 4 includes a liquid crystal display panel 7, a light emitting element 8 that transmits and illuminates the liquid crystal display panel 7, and a case body 9 that supports the liquid crystal display panel 7.
Japanese Patent No. 3718741

However, since the liquid crystal display panel 7 is arranged at a predetermined interval from the light emitting element 8 in order to prevent luminance unevenness of the liquid crystal display panel 7 that is transmitted and illuminated by the light emitting element 8, the thickness of the liquid crystal display 4 is reduced. There was a problem that the width W1 in the vertical direction was large.
The present invention has been made in view of this problem, and provides a light-emitting device that can be thinned.

  According to the first aspect of the present invention, the light-emitting element 27 and the first transmissive reflecting member that reflects the part L2 of the light L1 emitted from the light-emitting element 27 and transmits the other part L3. 28, a second transmission / reflection member 29 that reflects part L4 of the light L3 that has passed through the first transmission / reflection member 28, and transmits the other part L5, and the second transmission / reflection member 29. And a reflecting member 31 that reflects at least a part L8 of the light L5 that has passed therethrough.

  In the present invention, as described in claim 2, the transmittance of the second transmissive reflecting member 29 is lower than the transmittance of the first transmissive reflecting member 28.

  The light emitted from the light emitting element can be reflected by the plurality of transmitting and reflecting members and the reflecting member, so that the light emitting device can be thinned.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in which the present invention is applied to a vehicle head-up display device will be described with reference to the accompanying drawings.

  The vehicle head-up display device 21 has a liquid crystal display 22 and a reflector 23 accommodated in a housing 24. The liquid crystal display 22 includes a liquid crystal display panel 25 and a light emitting device 26 that transmits and illuminates the liquid crystal display panel 25. The liquid crystal display panel 25 has a polarizing member attached to the front and back surfaces of a liquid crystal cell. The light emitting device 26 includes a light emitting element 27, a first transmission / reflection member 28, a second transmission / reflection member 29, a third transmission / reflection member 30, a reflection member 31, and a case body 32.

  The reflector 23 includes a reflection mirror 36, a holding member 37, and a stepping motor 38. The reflection mirror 36 is formed by depositing a metal (for example, aluminum) on a resin (for example, polycarbonate) to form a reflection surface 36a. The reflecting surface 36a is a concave surface so that a virtual image is enlarged and displayed. The reflection mirror 36 is bonded to the holding member 37 with a double-sided adhesive tape. The holding member 37 is made of resin (for example, ABS), and the gear portion 40 and the shaft portion 41 are integrally formed. The shaft portion 41 is pivotally supported by the housing 24.

  A gear 42 is attached to the rotating shaft of the stepping motor 38, and the gear 42 is meshed with the gear portion 40 of the holding member 37. The reflection mirror 36 is supported in a rotatable state together with the holding member 37, and the reflection mirror 36 can be rotated by the stepping motor 38 to adjust the projection direction of the display light L. The user operates a push button switch (not shown) to adjust the angular position of the reflection mirror 36 so that the display light L is reflected at the position of the user's eyes (that is, the virtual image can be visually recognized).

  The housing 24 accommodates the liquid crystal display 22, the reflector 23, and the like. The housing 24 is formed with a window 24b through which the display light L is emitted, and a translucent cover 48 is disposed on the window 24b. The translucent cover 48 is made of a translucent resin (for example, acrylic) and has a curved shape. The housing 24 is provided with light shielding walls 24c and 24d. The light shielding wall 24c is formed so as to hang obliquely from the upper part of the housing 24, and prevents a phenomenon (washout) in which external light such as sunlight enters the liquid crystal display 22 and makes it difficult to see a virtual image. . The light shielding wall 24 d is erected at the lower part of the housing 24.

  Reference numeral 51 denotes an external light sensor such as a photodiode. The external light sensor 51 is mounted on the circuit board 52. The external light sensor 51 mounted on the circuit board 52 is fixed to a holding part that hangs down from the upper part of the housing 24. The external light sensor 51 receives light that has passed through the translucent cover 48, detects the brightness in front of the vehicle, and outputs illuminance data for adjusting the light emission luminance of the light emitting element 27. 53 is a cylindrical body, and this cylindrical body 53 is integrally formed with the light shielding wall 24c. The cylindrical body 53 has a substantially cylindrical shape and regulates the angular range of light incident on the external light sensor 51.

Next, the light emitting device 26 having the light emitting element 27, the first transmission / reflection member 28, the second transmission / reflection member 29, the third transmission / reflection member 30, and the reflection plate 31 will be described in detail.
The light emitting element 26 is made of, for example, a white light emitting diode, and is disposed behind the liquid crystal display panel 25. The first transmission / reflection member 28, the second transmission / reflection member 29, and the third transmission / reflection member 30 are, for example, beam splitters having no wavelength selectivity.

  The reflectance of the first transmission / reflection member 28 is about 25% (transmission is about 75%), the reflectance of the second transmission / reflection member 29 is about 33% (transmission is about 66%), and the third transmission The reflectance of the reflecting member 30 is about 50% (transmittance is about 50%). The first transmission / reflection member 28, the second transmission / reflection member 29, the third transmission / reflection member 30, and the reflection member 31 are inclined with respect to the optical axis of the light emitting element 27 at an angle of about 45 °.

  A part L2 of the light L1 emitted from the light emitting element 27 is reflected by the first transmission / reflection member 28, and the other part L3 transmits the first transmission / reflection member 28. A part L4 of the light L3 that has passed through the first transmission / reflection member 28 is reflected by the second transmission / reflection member 29, and the other part L5 passes through the second transmission / reflection member 29. The part L6 of the light L5 that has passed through the second transmission / reflection member 29 is reflected by the third transmission / reflection member 30, and the other part L7 transmits through the third transmission / reflection member 30. The light L7 that has passed through the third transmission / reflection member 30 is reflected by the reflection member 31.

  According to the present embodiment, the light emitted from the light emitting element 27 is reflected by the first, second, and third transmission / reflection members 28, 29, and 30 and the reflection member 31, and the liquid crystal display panel 25 is substantially omitted. Transmitting illumination can be performed with uniform brightness, and the interval between the light emitting element 27 and the liquid crystal display panel 25 can be reduced, so that the width W2 of the light emitting device 26 can be reduced.

Sectional drawing which shows embodiment of this invention. The principal part enlarged view of embodiment same as the above. The general-view figure which shows a prior art example. Sectional drawing which shows a prior art example same as the above.

Explanation of symbols

27 Light emitting element 28 First transmission / reflection member 29 Second transmission / reflection member 30 Third transmission / reflection member 31 Reflection member

Claims (2)

  A light-emitting element, a first transmission / reflection member that reflects part of the light emitted from the light-emitting element and transmits the other part, and a part of the light transmitted through the first transmission / reflection member are reflected And a second transmissive reflecting member that transmits the other part and a reflective member that reflects the light transmitted through the second transmissive reflecting member.   The light-emitting device according to claim 1, wherein the transmittance of the second transmissive reflecting member is lower than the transmittance of the first transmissive reflecting member.

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