Light emitting device and display unit using the light emitting device and reading device

• US 20050117190A1
• Filed: 02/27/2003
• Published: 06/02/2005
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Seo, Mitsuyoshi, Yamanaka, Atsushi, Iwauchi, Kenichi, Oohara, Akemi
• Granted Patent: US 7,510,300 B2
• Time in Patent Office: Days
• US Class Current: 359/237
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/37 Converter circuits

Abstract

A light emitting device provided with a plurality of types of light sources having different light emitting colors and with a light emission control means for allowing light to emit, during a specified period of monitoring a light emitting intensity, from at least one light source out of the plurality of types of light sources at a light emitting intensity different from that available outside the specified period. Accordingly, when a plurality of types of light sources are used, the light emitting intensities of a plurality of types of light sources can be monitored with light sensors of types fewer than the types of light sources to control while points and a brightness characteristics.

Claims

1-52. -52. (canceled)

53. A light emitting device comprising:

multiple types of light sources emitting light of different colors;

a light detection means for monitoring emission intensity of at least one light source among the multiple types of light sources; and

a light emission control means which performs control to provide a light emitting period in which all of the multiple types of the light sources emit light at a same time at predetermined emission intensities and a monitoring period in which at least one of the multiple types of the light sources emits light at emission intensity different from that in the light emitting period in which all of the multiple types of the light sources emit light at the same time, wherein

the light emission control means controls the emission intensity of the at least one light source among the multiple types of the light sources based on emission intensity information from the light detection means in the monitoring period to adjust composite light from the multiple types of the light sources to have a desired luminance or chromaticity.

54. A light emitting device according to claim 53, wherein the light emission control means turns off at least one light source among the multiple types of the light sources in the monitoring period.

55. A light emitting device according to claim 54, wherein the light emission control means shifts either timing to turn on each light source or timing to turn off each light source.

56. A light emitting device according to claim 53, wherein the light emission control means decreases the emission intensity of at least one light source among the multiple types of the light sources in the monitoring period.

57. A light emitting device according to claim 56, wherein the light emission control means shifts either timing to make the emission intensity of each light source to the predetermined emission intensity or timing to decrease the emission intensity.

58. A light emitting device according to claim 53, wherein the light emission control means increases the emission intensity of at least one light source among the multiple types of the light sources in the monitoring period.

59. A light emitting device according to claim 58, wherein the light emission control means shifts either timing to make the emission intensity of each light source to the predetermined emission intensity or timing to increase the emission intensity.

60. A light emitting device according to claim 53, wherein the light detection means has spectral sensitivity characteristics approximately matching luminosity factor characteristics with the light emission wavelength of the at least one light source among the multiple types of light sources being a center.

61. A light emitting device according to claim 53, wherein the light detection means comprises a luminosity factor filter for blocking infrared radiation.

62. A light emitting device according to claim 53, comprising a period in which all of the multiple types of the light sources are turned off, wherein

the light detection means monitors amount of light in a state that all of the multiple types of the light sources are turned off.

63. A light emitting device according to claim 53, comprising:

a light source unit including a plurality of three types of light sources;

a light guide plate for uniformly irradiating a plane with light from the light source unit; and

an optical sensor as a light detection means provided in the vicinity of the light guide plate.

64. A light emitting device according to claim 53, comprising:

a first light source unit including a plurality of one or two types of light sources;

a first light guide plate for uniformly irradiating a plane with light from the first light source unit;

a second light source unit including one or two type of light sources different from the above light sources;

a second light guide plate for uniformly irradiating a plane with light from the second light source unit and the first light guide plate; and

an optical sensor as a light detection means provided in the vicinity of the first and the second light guide plates.

65. A display apparatus using a light emitting device according to claim 53.

66. A display apparatus using a light emitting device according to claim 53, wherein:

when a level of a luminance signal included in an input video signal is equal to or less than the threshold value, the monitoring period is started.

67. A display apparatus using a light emitting device according to claim 53, wherein:

in the monitoring period, a size of a drive signal of the display apparatus is extended.

68. A read apparatus using a light emitting device according to claim 53.